Microtechnologies: Past, present and future

MICROTECHNOLOGIES:
Past, Present and future
Further presentations:
www.symbaloo.com/mix/manufacturingtechnology
Dr. Endika Gandarias Mintegi

MICROTECHNOLOGIES: Past, Present and Future
AUTHOR
by E. Gandarias
Dr. ENDIKA GANDARIAS MINTEGI
Mechanical and Manufacturing department
Mondragon Unibertsitatea - www.mondragon.edu
(Basque Country)
www.linkedin.com/in/endika-gandarias-mintegi-91174653

INDEX
1. INTRODUCTION__________________________________ 2
2. HISTORICAL BACKGROUND________________________ 2
3. TERMINOLOGY __________________________________ 4
3.1. MicroStructures or MicroSystems Technologies/
MicroElectroMechanicalSystems (MST/MEMS)
3.2. MicroEngineering Technologies (MET)
4. MICROMANUFACTURING RESEARCH & DEVELOPMENT_
7
4.1. Research policy in Asia
4.2. Research policy in USA
4.3. Research policy in Europe
5. MARKET EXPECTATIONS__________________________11
6. MICROMANUFACTURING APPLICATIONS____________ 14
6.1. Automotive & Transport means
6.2. Information technology & Telecommunications
6.3. Health & Biotechnologies
6.4. Instrumentation
7. MICROMANUFACTURING TECHNOLOGY
CLASSIFICATION__________________________________
19
7.1. MEMS processes
7.2. Energy assisted processes
7.3. Mechanical processes
7.4. Replication techniques
7.5. Handling, assembly, packaging, quality assurance &
metrology
8. FUTURE CHALLENGES___________________________ 34
9. BIBLIOGRAPHICAL REFERENCES __________________ 36
by E. Gandarias 3

by E. Gandarias

1. INTRODUCTION
As Dr. Richard Feynman stated in the late 1950s, world’s miniaturization technology
has advanced at an astonishing pace. The forerunner of this technology was mostly the
electronics industry with its need for manufacturing processes for electronic
components, like printed circuit boards and Integrated Circuits (IC). However, currently
the market of miniature technologies supports in general, a very fast growing market in
a broad field of applications, especially in the medical, biotechnology,
telecommunications and energy fields.
This chapter represents a general review of the microtechnologies and many
illustrations have been included in order to provide a better understanding. Aspects
such as the historical background, terminology, research & development efforts in
various countries, market expectations & future trends, technology classification and
application and future trends will be analysed.
2. HISTORICAL BACKGROUND
Since the forties and through the next decade, many important advances were
made in the field of microtechnologies; a significant one was the invention of transistors
by Bardeen, Brattain and Shockley that fetched them the Nobel Prize in Physics in
1956 (see Fig. 2.1). Transistor had a tremendous impact on computer design, replacing
costly, energy-inefficient and unreliable vacuum tubes, as a device that could act as an
electric switch. Another important advancement, upon which the current IC industry
was built, was the oxide-masking process developed at Bell Labs in 1954 [1
].
Not long after these inventions, the idea to extend this technology to more
sophisticated geometries arose. In fact, miniaturised devices were already invented,
but their dimensions were too large to be considered micro-devices.
Inspired by the performance of biological systems and their ability to perform
functions and store information within their microscopic volumes, R. Feynman
discussed the possibilities of making miniaturised mechanical devices. Although he

a b
Fig. 2.1 The first transistor: (a) invented in 1947 at Bell Labs [2
]; (b) transistor
inventors William Shockley (seated), John Bardeen (in glasses), and Walter
Brattain [3
].
Fig. 2.2 The first IC, invented in 1958 by Jack Kilby, Texas Instruments,
contained a total of five components (transistors, resistors and capacitors)
[Error: Reference source not found]. Today's Pentium-IV processor contains
over 125 million transistors on it. [4
].
was building on the techniques available during his time, Feynman made spectacular
speculations about the development of the miniaturization industry in terms of both
manufacturing and potential processing and operating problems [5
, 6
].
By the 1970s, the IC industry had made considerable progress since its first
appearance at Texas Instruments in the late fifties (see Fig. 2.2).
In a few decades the continuous advances involved a considerable improvement of
productivity and quality of life through proliferation of computers, electronic
communication and consumer electronics.
Most frequently cited trend in this development is probably the integration level
achieved in the circuits, usually expressed as Moore’s Law, which states that the
number of components per chip doubles every 2 years. Other principal trends are
shown in Table 2.1.
Nowadays, society demands that the success achieved in the miniaturization of
microelectronics should be extended to other fields. This miniaturization involves many
improvements, mentioned as follows.

• Energy and materials consumption during manufacturing;
• Lightness and portability;
• Increase of selectivity and sensitivity;
• Use of more intelligent materials with structures at the nanoscale;
• Taking advantage of scaling when scaling works in the micro domain (e.g.
improved thermal management, etc.);
• Minimally invasive techniques;
• Exploitation of new effects through the breakdown of continuum theory in
the micro domain;
• Cost/performance advantages.
TREND EXAMPLE
Integration level Components/chip, Moore’s Law
Cost Cost per function
Speed Microprocessor clock rate, GHz
Power Laptop or cell phone battery life
Compactness Small and light-weight products
Functionality Non-volatile memory, imager
Table 2.1 Improvement trends for ICs enabled by feature scaling [7
].
These technologies integrated into Micromanufacturing Technologies present an
important role for the current and future industry. They bridge the gap between the
nano and macro worlds and they are completely changing the thinking as to how, when
or where products should be manufactured (e.g. on-site, on-demand, in the hospital
operating room or on-board a warship).
3. TERMINOLOGY
3.1. MicroStructures or MicroSystems Technologies/
MicroElectroMechanicalSystems (MST/MEMS)
Micromachining techniques were developed over thirty years ago as a result of
semiconductor technology. It was found that, through selective doping and etching, one
could produce three-dimensional elements on a silicon wafer.
This technology became known worldwide as MST (MicroStructures or
MicroSystems Technology). Somewhat more recently, companies in the United States
adopted the term MEMS (MicroElectroMechanical Systems) as the descriptor of
choice, whereas the rest of the world chose to stay with the original term MST. The
difference in nomenclature has created substantial confusion in this emerging industry,
and may actually have inhibited its growth.

Etymologically, the term MEMS places limitations on the technology and, therefore,
MEMS should more rightly be considered a subset of MST rather than a broad-based
descriptor. A true MEMS device must include both electrical and mechanical
components which, consequently imply that there must be at least one moving or
deformable part and that electricity must enter into its operation in some fashion.
3.2 MicroEngineering Technologies (MET)
While micro-scale technologies were well established in the semiconductor and
microelectronics fields, the same cannot be said for manufacturing micro features and
products in materials different from silicon.
These technologies are generally classified as MicroEngineering Technologies
(MET) and refer to the creation of high-precision three-dimensional (3D) products using
a variety of materials and possessing features with sizes ranging from tens of microns
to a few millimetres (See Fig. 2.3).
Fig. 2.3 Dimensional size for the micro-mechanical machining [8
].
There is no clear agreement either defining the micro engineering or what a micro
product or micro component is considered. Most authors talk about micro engineering
simply in terms of size but L. Alting et al. [9
] gave a more general view that has been
accepted in this thesis.
Micro engineering is closely related to the whole process of conception, design and
manufacture of micro products and thus, cannot be totally expressed without a
definition of the concept of micro product itself.
It is difficult to give an exact definition of a term that seems to be only size-related in
a rapidly changing era. The definition should, therefore, contain the philosophy and
characteristics of a micro product. Of course a micro product is characterised by small
dimensions, either of the product itself, or of functional features or structures of the
product.
From a geometrical point of view, micro products can be classified as two-
dimensional structures (2D) (optical gratings), 2D-structures with a third dimension
(2½D) (fluid sensors) and real three-dimensional structures (3D) (components for
hearing aids). The geometry affects the possible manufacturing methods and the
associated production support in terms of handling, assembly and metrology.
Another important characteristic of micro products is integration. The reason for
miniaturization has to be taken into account in order to distinguish between those

products that need to be “small” to reach a more compact and portable version, and
those products whose functionality is achievable only by virtue of their small
dimensions.
Finally, a micro product is usually constituted by several components. Thus it is
apparent to distinguish between a micro product and a micro component.
Thus, the definition of micro engineering accepted is as follows: Micro engineering
deals with development and manufacture of products, whose functional features, or at
least one dimension, are in the order of μm. The products are usually characterised by
a high-degree of integration of functionalities and components.
The creation of truly three-dimensional miniature parts with a high aspect ratio is
always a challenge in micromachining in terms of achievable accuracy and relative
accuracies. Whereas the absolute accuracy (feature size) that can be reached in
micromachining is excellent from millimetres range down to less than 1 µm, the relative
accuracy is rather bad. In traditional manufacturing of precision parts; relative
accuracies of 10-6
can be attained, but these relative accuracies cannot be reached in
micromachining [10
]. Fig. 2.4 shows habitual range of sizes to clarify about the range of
sizes, accuracies, and relative accuracies one talks in micromachining.
Fig. 2.4 Precision machining in terms of absolute sizes and absolute & relative
tolerances [Error: Reference source not found].
With some processes, surface finishes as good as 1 nm can be created, which are
approximately ten times the size of an atom. If the relative accuracy of a house, which
is not considered to be a precision part is compared with the relative accuracy of a

lithography based micromachine, it is noticed that both are approximately the same.
The optimum level in relative accuracies is usually achieved at sizes that are bigger
than micromachined features. In general, it is seen that the smaller the micromachined
part is, the more difficult it is to achieve a good relative accuracy.
Other challenges that need to be considered in micromachining are the assembly
and handling of the small parts, and the strict requirements for the alignment and
positioning accuracy of the tools.
4. MICROMANUFACTURING RESEARCH &
DEVELOPMENT
In general, R&D infrastructures and governmental support are key factors for
promoting technological and industrial competitiveness of a country. In the case of
microtechnologies, this is even truer when considering the deeply rooted risk in this
sector and the need for basic research.
Considering the three main world economic regions Europe, USA and Japan with
respect to microtechnologies, they differ considerably in the areas of research policy,
application level and market penetration.
USA and Japan appear to have recognised ahead of Europe the importance of
micro and nano technologies as the engine for the growth of their industrial system. In
the case of nanotechnologies in particular, the efforts of USA and Japan have been
significantly more intense, especially in the USA leading various fields of application.
However, emphasis on micromanufacturing R&D is lagging far behind in USA
compared with the rest of the world despite the previously realised vast investment.
This will undoubtedly have serious long-term implications, since it is well-recognised
that micromanufacturing will be a critical enabling technology in bridging the gap
between nano-science and technology developments, and their realization in useful
products and processes.
Table 2.2 reports all trends that micromanufacturing technologies are supporting.
Table 2.2 Summary of the relative status of international micromanufacturing technology
development (2005) [].

4.1. Research policy in Asia
Activity in Asia is basically focused on Japan, Korea, Singapore and Taiwan. The
effort realised in Australia and Hong Kong is remarkable as well although, the activities
in these countries have been mostly pushed by universities.
Both Japan and Korea support large, multi-year country-wide programs in
micromanufacturing and micro-factories, although in Korea this has been a very recent
phenomenon. In Japan, the 10-Year Micromachine Program (1991-2001) constituted a
major government investment that started a number of initiatives with industry that
continue even today. Major successes include micromanufacturing and assembly
systems at Olympus, Seiko, Hitachi, Fanuc, and Mitsubishi. In Korea, the Korean
Institute of Machinery and Metals (KIMM) was awarded a major government contract
for micro-factory development (saving energy, saving space and saving resources)
[Error: Reference source not found] (see Fig. 2.5).
Fig. 2.5 Micro-factory project [11
].
In Japan, both the National Institute for Advanced Industrial Science & Technology
and The Institute of Physical & Chemical Research (RIKEN) have missions heavily
oriented towards R&D for industrial application, and both make major efforts directed
towards micromanufacturing with very impressive results. In both laboratories, the R&D
programs are producing very sophisticated, complex, and highly innovative processing
methods. It is interesting to note that most of the micromanufacturing equipment
developed could be classified as somewhat exotic in nature, directed toward
sophisticated, low-volume, high-precision needs of specific products and devices, and
requiring a significant investment costing between several $100K to $1 million.
The companies that have been strong over the past two to three decades in
manufacturing leadership, e.g. FANUC (controls), Matsushita Electric (consumer
products), Mitsubishi Electric (electronic products, devices) and Olympus (optics),

seem to have invested heavily in micromanufacturing technologies continuously over
the last fifteen or so years [12
].
Regarding the relationship between the universities and companies in Japan,
companies expect universities to teach fundamental principles and provide broad
scientific education, whereas they provide focused and application-oriented special
training during the early years of employment. The government policy related to
intellectual property (IP) provides a favourable situation for industry regarding
university-based innovations and inventor-ship under government funding. Companies
can purchase licenses from the government, that owns all such funded IP, to
commercialize university-based inventions.
In Taiwan, there is some institutional government investment, but it is mostly
through large corporations with strong product focus, typical of Japan’s “branding”
strategy. The Industrial Technology Research Institute (ITRI) is the major government-
supported laboratory conducting research in support of Taiwan’s high-technology
industries, with a large segment being devoted to micromanufacturing research and
development. Another government facility, the Metal Industries Research Institute
(MIRI) is initiating a program in micro/meso-scale manufacturing methods (M4
) [13
].
4.2 Research policy in USA
The USA is surely the leading country for microtechnologies in many application
fields due to the vast efforts realised in the development of IC since the late sixties, and
the impulse given to the evolution of the silicon microfabrication technologies. This
allowed American companies, especially in California (Silicon Valley) a relatively quick
access to such sophisticated processing technologies that are essential for the
development of microsystems. Over the last 20 years, the USA emphasised MEMS,
and many start-up companies were promoted; thanks to the positive conditions to
produce low volume-price rates.
Public support policies started slowly in MEMS field were principally pushed by the
National Science Foundation (NSF) with less than $1million per year. However, the
Defence Department is currently the biggest investor with funds exceeding $50 millions
per year.
Nevertheless, the effort devoted to R&D is limited at present with respect to the
effort in production due to a change in the USA government’s investment policy. The
USA government regards nanotechnologies as a national priority, emphasising the
impact of such technologies mainly on structural (mechanical) properties of new
materials, on diagnosis and therapy, and on storing, processing and transmitting data.
This matter has relegated all investments in micromanufacturing technologies aside,
which is allowing Asian and European countries to gradually reduce the difference in
the state of the art micromanufacturing technologies with USA [Error: Reference source
not found].
4.3. Research policy in Europe

Historically, in the European Union there were no dedicated programs targeting the
specific needs and requirements of microtechnologies, and its development has been
strongly linked to research centres and universities.
During the past few years, there has been an increase in government investment in
institutions. The emphasis seems to be on creating an enabling infrastructure to
support the conversion of research results into technologies to the point that they are
attractive to companies for application and commercialization [Error: Reference source
not found].
Opportunities for micro systems can also be found in EURIMUS II program, an
industrial initiative inside the EUREKA programme to support the development of
products and systems exploiting microtechnologies as well as enabling technologies,
manufacturing and equipment for all application domains [14
].
Additional support is provided by two other initiatives: NEXUS (Network of
Excellence in Multifunctional Microsystems) and EUROPRACTICE. Established in
1992 with European Community support, NEXUS aims to promote R&D and
commercialisation of MEMS and microsystems through the creation of a set of co-
ordinated forums for discussion and exchange of information among researchers and
workers in the MST field. EUROPRACTICE, which links together several European
competence centres (also includes non European Union (EU) participants), provides
support in designing, prototyping and manufacturing of micro systems [15
].
More recently, inside the VI EU´s Framework Programme, the Multi-Material Micro
Manufacture (4M) Network of Excellence has been created. Its main aim is to improve
research collaboration in the development of Micro and Nano Technology (MNT) for the
batch-manufacture of micro-components and devices in a variety of materials for future
microsystem products.
Furthermore, many projects related to microtechnologies have been approved, like
LAUNCH-MICRO (MicroTechnologies for Re-launching European Machine
Manufacturing SMEs), PROFORM (an innovative manufacture process concept for a
flexible and cost effective production of the vehicle body in white: Profile forming),
MASMICRO (integration of manufacturing systems for mass-manufacture of
miniature/micro products bulk forming), Nano-CMM (universal and flexible 3D
coordinate metrology for micro and nano components production), PHODYE (new
photonic systems on a chip based on dyes for sensor applications scalable at wafer
fabrication) or Production4micro (production technologies for micro systems).
It is clear that Europe, inside and outside the EU, is stepping up its effort to increase
its competitiveness in this field with respect to USA and Japan. However, the situation
of the development varies from country to country mainly due to a bigger investment in
recent years in micromanufacturing R&D; Germany, France, UK, Switzerland and some
of the Scandinavian countries seem to be already better placed than others in this
effort.
The great investments realised in the field of microtechnologies by Germany has led
it to the third position in the world, just behind the USA and Japan. There is a mix of
government and private/industry funding and projects tend to be long-term. Emphasis
is on refining and fine-tuning technologies to make them commercially attractive and
easily adapted. Links with universities seem to be very important to success. The

“Fraunhofer System”, which is a splendid case, is a major driving force for
micromanufacturing research, technology development and commercialization with
strong ties with the university system and industry obtaining impressive results. On the
other hand, there is abundant evidence of the desire to commercialize smaller
micromanufacturing machine tools and accessories on a commodity basis, examples
include Kugler’s Flycutter and MicroTURN machines, the Carl Zeiss F25 small-scale
CMM, the Klocke Nanotechnik microscale robotic systems, etc. [Error: Reference
source not found].
5. MARKET EXPECTATIONS
According to a study of the European NEXUS organization (Network of Excellence
in Multifunctional Microsystems), the worldwide market for Microsystems (including
MEMS/MST) technologies is growing at an average rate of 11% per year from $36
billion in 2005 to $52 billion in 2009. This analysis includes a break-out of the market
for 1st
level package MEMS/MST, e.g. the inkjet head of an inkjet printer, from $11.5
billion in 2004 to $25 billion in 2009 [Error: Reference source not found].
Fig. 2.6 offers a broad view of the current market segmentation along MNT
functionality and maturity.
Fig. 2.6 Typology of microsystems markets [Error: Reference source not
found].
NEXUS “Market Analysis for MEMS and Microsystems III, 2005-2009” report states
that MST/MEMS sensors and actuators consolidate their position in established
Information Technology (IT) peripheral markets for read/write heads and inkjet heads,
in addition to creating new opportunities in areas such as microphones, memories,
micro energy sources and chip coolers (see Fig. 2.7) [Error: Reference source not
found].
EnablingMNT market researchers (an international team of experts in the business
of micro and nano technologies) expect the automotive sector to remain a major
application field with several high-volume safety products including air bags and tire
pressure monitoring systems.

The major boost to the growing market will be the consumer electronics segment,
which is forecast to almost quadruple its share from 6% of the MST/MEMS market in
2004 to 22% in 2009. Experts see rear and front projection TVs for home theatre, as
well as HDDs serving the increasing storage requirements of digital equipment such as
DVD recorders, digital cameras, camcorders and portable MP3 players. A big driving
force is the mobile phone, which already features motion sensors and is amenable to a
variety of additional sensors and functions like liquid lenses for camera zoom,
fingerprint sensors, micro-fuel cell power sources, gas sensors and weather
barometers (see Fig. 2.8).
Fig. 2.7 Total market for 26 MST/MEMS products, 2004-2009 [Error: Reference source
not found].
Fig. 2.8 Market Analysis for MEMS and Microsystems III 2004 – 2009 [Error:
Reference source not found].

Concerning the total amount expected to be invested in MST and MET, MET are far
behind MST because they are emerging technologies. However, regarding expansion
percentage expectations, MET present a sharp promising growth and extension to
many applications and fields.
Microsystems have experienced a strong evolution since the appearance of the
initial read/write and inkjet heads and the first micro acceleration sensors used in
airbags. Existing microsystem markets worth a few billion euros (e.g. inkjet heads)
attest the economical interest of microsystems. It should be noted that the overall
microsystem market growth depends equally on established (e.g. pressure sensor,
inkjet) and new (e.g. displays) applications. These trends are summarised in Fig. 2.9.
Automotive remains a driving force for microsystem innovation by offering high
volume applications with only a few major customers. Microsystem supply chain for
automotive shows that it can innovate on all levels (materials, components, systems,
usage).
The biomedical and telecommunications sectors are also major drivers for current
and future microsystems development. In this field, for example, in-vitro diagnostics
(mostly biochips, bio arrays and micro plates) are expected to become a very strong
large-volume market.
Fig. 2.9 Microtechnologies Timeline [Error: Reference source not found].

Fig. 2.10 Transistors Per IC Trends [Error: Reference source not found].
The IT field depends strongly on miniaturization capabilities. The engine that
powers the computer revolution is micromanufacturing. Micromanufacturing packs
more and more devices into each chip devices that switch faster and consume less
energy. In 1945, computers used vacuum tubes with the size of a thumb. As shown in
Fig. 2.10, today they use transistors so small that a hundred of them could sit on the
tiny, round, transversal section of a cut off hair.
All signs point to a revolution that advances to the limits set by natural law and the
molecular graininess of matter. Trends in miniaturization point to remarkable results
around 2015; device sizes will shrink to molecular dimensions and switching energies
will reduce to the scale of molecular vibrations. With devices like these, a million
modern supercomputers could fit in a pocket. Although detailed studies already show
how such devices can work and how they can be made, using molecules as building
blocks, will require vast efforts before results are obtained.
6. MICROMANUFACTURING APPLICATIONS
Miniaturization was first conceived for military applications in the 1960s. However,
information technology and communications were the first sectors to use the
techniques, developed and paid by the military for industrial and consumer products.
Without such investments in miniaturization, PCs, mobile phones and the Internet
would not have been possible these days.
In forecasting the trend, it is expected that the progress of society will be tightly
connected with technological evolution, affecting both the available products and the
services offered. The most spectacular results in the progress of miniaturization will
probably be seen in the increase of processing power of mainframe computers and
PCs [Error: Reference source not found].
There is an increasing demand to make existing products smaller, producing
microcomponents with tolerances in the submicron range. The broad range of industrial

applications for micro machined components could be divided in the following fields
(see Fig. 2.11):
• Automotive & transport means;
• Information technologies (IT) & Telecommunications;
• Health and biotechnologies;
• Instrumentation & sensors.
Many of these applications will have a drastic increase in the world market in the
upcoming years.
IT and Health/Biotech, with around 60% and 30% respectively of the total, have
majority of the market. However, Telecommunication that somewhere between 5% and
7% of the total at present, is showing one of the highest rates of growth, and in the
future, it will be one of the main driving forces for micro and especially, nano
technologies [Error: Reference source not found].
Applications in the Automotive and Telecommunication sectors have gained
increasing ground during the last few years and their share of the market continues to
expand.
Instrumentation, namely sensors, has a high degree of overlap with the other three
sectors considered. There are also other rather interesting applications for these
miniaturised systems, such as, sensors for environmental control or in domotics that
justifies separate treatment.
The situation and trends in the four specified application fields is illustrated in more
detail in the following sections. Some of the products listed below have been in the
market for quite a substantial length of time, but many did not even exist until recently.

Fig. 2.11 Principal micromanufacturing industrial application fields.
6.1 Automotive & Transport means
Automotive applications for microtechnologies address problems mainly related to
the increase in safety, quality and reliability requirements. There is a strong demand for
better economy of operation as well as more comfortable transport means and the
production of environmentally sustainable components.
The present range of commercial products refers to micro system technology (MST)
products and to miniaturised electronics and systems (see Fig. 2.12). However,
microtechnologies will also find their way in other fields such as new types of paints,
new catalysts and new materials, all of which could greatly influence the characteristics
and the use of the next generation cars.
In a complex electronic/electro-mechanical system such as the modern car, the
need for effective, accurate, reliable and low-cost electronics and sensors are pressing.
Whereas in 1980, electronics accounted for merely 2% of the total cost of the car,
today it has reached almost 30% [Error: Reference source not found]. There are 20 to
100 sensors installed in a modern automobile depending on the make and model.
Some of the most demanding sensors positioned currently in cars are accelerometers
(airbag release), micro-nozzle systems (injection system), pressure sensors (gas
recirculation), gyroscopes (navigation), level, light & temperature sensors (oil/gas
indicator, turn on lights and outside/inside temperature measurement), parking sensors
(collision avoidance) and air flow sensors (air/flow ratio control) [16
].
AUTOMOTIVE &
TRANSPORT MEANS
INFORMATION TECHNOLOGIES
& TELECOMMUNICATIONS
HEALTH &
BIOTECHNOLOGIESINSTRUMENTATION &
SENSORS

a
b c d
Fig. 2.12 Automotive and transport mean applications; (a) Some micromachining
applications in automotive sensing [17
]; (b) MS7000 Series accelerometer [18
];
(c) Diesel fuel injection nozzle [19
]; (d) Silicon Micro Ring Gyro [20
].
6.2 Information technology & Telecommunications
It is hard to deny that our society evolves towards an information society. As a
matter of fact, today every citizen, at least in the developed countries, is in position to
receive, store, process and transmit a huge quantity of information, much more than
even few years ago, and this quantity of information will steadily increase in the next
years.
Microtechnology has been one of the driving forces pushing this trend, since each
progress in information storage, processing and sharing is accompanied by a progress
in reduction of the geometrical features of the used devices. Besides this, demand for
increasing the performance and for reducing the costs have been main factors in this
trend.

A b c
d e
Fig. 2.13 IT & Telecommunication applications; (a) Toshiba's 0.85 inch hard disk drive
can store 4 GB of data [21
]; (b) Single nozzle (diameter 5 µm) [22
]; (c) Micro-
mirrors fabricated on the surface of a silicon wafer for an image projector [23
];
(d) Virtual keyboard [24
]; (e) Acceleration Sensing Glove [25
].
This application area today also constitutes the largest micromanufacturing
technologies market dominated principally by two products, namely, the hard disk drive
heads (HDD) and ink-jet print heads. Other important applications involve magneto-
optical heads, projection displays, electronic papers, gyroscopes, optical switches,
attenuators, gain equalizers, micro-relays, RF components, etc. [Error: Reference
source not found] (see Fig. 2.13).
6.3. Health & Biotechnologies
Many promising expectative claim that health & biotechnologies field will have a
pervasive and profound impact on the future of microtechnologies. Demand to address
problems like miniaturization of existing devices, increasing in biocompatibility and
functionality, or decreasing in time for measuring and analysis are needed.
Medical and biomedical markets show promise in a wide variety of applications as
shown in Fig. 2.14 [Error: Reference source not found]. They could be grouped as:
• Implantable systems: cardiac pacemakers, implantable hearing aids;
• Diagnostic systems: blood pressure sensors, glucose sensors;
• Minimal-invasive surgery or non-invasive surgery: endoscopy, tools for
minimally invasive surgery (see Fig. 2.15);
• Pharmaceutical applications: intelligent drug delivery systems and smart
pharmaceuticals;
• Biotechnical applications: biochip/lab-on a chip technology, nano particles in
gene technology and therapy;
• Biofunctional devices: tissue engineering for bioartificial organs and skin.

A b c
d e f
Fig. 2.14 Health & biotechnology applications; (a) In Vivo Magnetically guided Micro-
Robots ETH Zurich [Error: Reference source not found]; (b) Hearing aid device
[26
]; (c) Microfluidic cytological tool, for cell counting and separation [27
]; (d) Bucal
Tubes and brackets for dental applications [28
]; (e) Lilliput chip for microbiological
diagnostic system [29
]; (f) Micro-gripper for surgery [30
].
Fig. 2.15 World Market Share of Minimally Invasive Surgery Products [Error: Reference
source not found].
6.4. Instrumentation
The term instrumentation can be referred to a wide range of products and
microtechnologies can have a profound impact. The pursued goals are broad due to
the variety in products; large-scale miniaturization, user’s comfort increase, reduction of
energy & raw material consumption & product’s final cost, autonomous and remote
control, easy maintenance, improvement of environment quality, etc.

Sensors take a large relevancy in this field since they make feasible the detection,
determination or measurement of physical and chemical parameters in sectors like
ambient conditions control, industrial automation, house control and domotics, agro-
industrial production control or metrology (see Fig. 2.16). Today, the market for sensors
is segmented into pressure, temperature, acceleration, flow and force where pressure
and temperature sensors cover practically two thirds of the market [Error: Reference
source not found].
7. MICROMANUFACTURING TECHNOLOGY
CLASSIFICATION
The number and diversity of technologies to produce microcomponents and
microproducts is enormous. Those could be classified first as top-down manufacturing
methods; starting from bigger building blocks and reducing them into smaller pieces.
Second as bottom-up manufacturing methods, in which small particles such as
atoms/molecules are added for the construction of bigger functional structures. And
third as either the development of entirely new technologies or combination of existing
technologies.
a b c
d e f
Fig. 2.16 Instrumentation applications; (a) Silicon micromechanical microphone for a
mobile telephone or a hearing aid [31
]; (b) Gas sensor microchip [32
]; (c) Wireless
micro-weather station (size of a film canister) [33
]; (d) Micro-spectrometer [34
]; (e)
Biometric device [35
]; (f) Gas sensor with oil isolation [Error: Reference source
not found].

Similarly, many other classifications for micromanufaturing technologies have been
reported. Mazusawa [Error: Reference source not found] for instance, classified
micromachining technologies according to their working principle or phenomena giving
the advantages and disadvantages of each of them. Table 2.3 depicts these
considerations combined with a description of the process/material interaction.
Madou listed most popular miniaturization techniques with their respective
characteristics organising as traditional or non-traditional methods and lithographic or
non-lithographic method and gave an extensive overview of the existing
microfabrication technologies [2] (see Table 2.4).
Some other authors divided the micromanufacturing technologies in removal,
deposition and molding [36
], others from University Nebraska-Lincoln made a
classification considering technologies which used tools (solid or image) or masks
(anisotropic and isotropic) [37
], etc.
Working Principle
Material interaction
Subtractive
Mass
containing
Additive Joining
Mechanical force
Cutting
Grinding
Blasting
Ultrasonic
machining
Rolling
Deep drawing
Forging
Punching
Ultrasound
Cold pressure
welding
Melting/Vaporization
(Thermal)
EDM
LBM
EBM
CVD
PVD
Welding
Soldering
Bonding
Ablation LBM
Dissolution
ECM
Isot.& anisot.
etching
Reactive ion
etching
Solidification
Casting
Injection
moulding
Recomposition
Electroforming
Chemical
deposition
Polymerisation/Lamination
Stereo-lithography
Photo-forming
Polymer
deposition
Gluing
Sintering
Combination of
mechanical and
thermal principles
Table 2.3 Overview of technologies for manufacturing of micro products by Mazusawa
[38
].

Miniaturization methods (Fundamentals of Microfabrication)
Traditional techniques
(not involving
photolithography-
defined mask)
Non traditional
techniques (involving
photolithography-
defined mask)
Non traditional
techniques (not using
photolithography-
defined mask)
AFM, STM (A,S), (Se)
Self-assembled monolayers
LIGA (S/A)
UV transparent resists (S/A)
Molded polysilicon HEXSIL (S/A)
Erect polysilicon (S/A)
Micromolding (A), (Ba)
Photofabrication (S)
Photochemical milling (S)
Wet etching of anisotropic material (S)
Dry etching (S)
Polysilicon surface micromach. (S/A)
SOI (S)
LBM (S/A), (Se)
PBM (S/A), (Se/Ba)
Stereolithography (A), (Se)
Ultraprecision mechanical mach. (S), (Se)
Microdispensing (A), (Se/Ba)
Injection molding, hot embossing (A), (Ba)
Power blasting (S), (Se)
Abrasive water jet (S), (Se)
Chemical Milling (S), (Ba)
Electrochemical machining (S/A), (Ba)
EDM (S), (Se)
EDWC (S), (Se)
EBM (S/A), (Se)
Continuous deposition (A), (C)
FIB (S/A), (Se)
Hybrid thick film (A), (Ba)
A=Additive C=ContinuousS=SerialBa=BatchS=Subtractive
Table 2.4 Classification of miniaturization methods by Madou [Error: Reference source
not found].
However, Brinksmeier’s classification [Error: Reference source not found] (see Fig.
2.17) is currently one of the most widespread and it is the accepted one in this thesis.
The machining of precision parts and micro structures is subdivided into two general
types of technologies having different origins; MicroSystem Technologies (MST) and
MicroEngineering Technologies (MET). MST are qualified for the manufacture of
products of Micro Electro Mechanical Systems (MEMS) and Micro Opto Electro
Mechanical Systems (MOEMS). MET comprise the production of highly precise
mechanical components, moulds and microstructured surfaces.
Next, regardless of its origin, Brinksmeier classifies the micromanufacturing
technologies in four groups:
• MEMS processes, like UV-lithography, silicon-micromachining and LIGA.
• Energy assisted processes like Laser Beam Machining, Focused Ion Beam
Machining, Electron Beam Machining and Micro Electro Discharge
Machining.
• Mechanical processes like diamond machining (e.g. turning, milling, drilling
and polishing), micromilling or microgrinding.
• Replication techniques like forming, injection moulding or casting. These
technologies are suggested in a class on their own, although they require a
previous micromanufacturing step to achieve the moulds.
• In addition to these four groups, Brinksmeier includes an additional group
where important steps for micromanufacturing such as handling, assembly
and metrology appear.

Fig. 2.17 shows graphically the Brinksmeier´s classification although it should be
mentioned that groups are not fully independent among themselves and that, there can
be an overlapping between the categories. The size of the arrows indicates how
frequently each group of processes are employed in the MST and MET technologies.
In the following sections most widespread processes and production systems used
in micromanufacturing will be exposed briefly.
7.1 MEMS processes
The manufacturing processes related to the Micro Electro Mechanical Systems
(MEMS) and microelectronics fields are based on 2D or planar technologies. This
implies the construction of components or products is on or in flat wafers.
MEMS products take their starting point in a prepared wafer (usually silicon) cleaned
and oxidised. Then, they are formed by creating patterns in the various layers of the
wafer. Pattern transfer consists of a photographical transfer of the desired pattern to a
photosensitive film covering the wafer, followed by a chemical or physical process to
remove or add material in order to create the pattern [Error: Reference source not
found]. This basic flow of MEMS micromachining is depicted in Fig. 2.18.
Photo-lithography is the basic technique used in pattern transferring between many
others like X-ray lithography, charged particle beam lithography, extreme ultra violet
lithography, etc. Besides these, the potential of the emerging lithography methods is
Microsystem Technologies
(MST)
Microengineering Technologies
(MET)
MEMS
processes
Replication
techniques
Mechanical
processes
Energy assisted
processes
Handling, assembly, packaging, quality assurance and metrology
T
e
c
h
n
o
l
o
g
i
e
s
Origin
Micro
Product
Micro
Product
Fig. 2.17 Process technologies for machining of precision parts and microstructures by
Brinksmeier [Error: Reference source not found].

noticeable, e.g. stereo-lithography, in which the possibility to build truly 3D
microstructures is present (see Fig. 2.19a).
Most usual chemical or physical processes mentioned above are listed in Table 2.5.
Fig. 2.18 Basic flow of MEMS micromachining.
The microfabrication by MEMS processes is currently accomplished by three major
technologies, namely, bulk micromachining, surface micromachining and micromolding
(LIGA). These techniques group different processes mentioned before.
7.1.1 Bulk Micromachining
In bulk micromachining processes, a portion of the substrate (bulk) is
removed in order to create free-standing mechanical structures (such as beams
and membranes) or unique three-dimensional features (such as cavities,
through wafer holes) by orientation dependent (isotropic) and/or orientation
independent (anisotropic) etchants (see Fig. 2.19b-c). Bulk micromachining can
be applied to silicon, glass, gallium arsenide and other materials of interests [39
].
This technique was the conventional one utilised in the IC industry; therefore,
it was also adapted and utilised, in microfabrication of MEMS, first among other
techniques from the IC industry [Error: Reference source not found].

Thin film deposition
(additive processes)
Etching
(material removal)
CVD
• Atmospheric pressure
• Low pressure
• Plasma enhanced
• Vapour phase epitaxy
PVD
• Vacuum evaporation
• Molecular beam epitaxy
• Sputtering
Electrochemical deposition
• Electroplating
• Electroless plating
Spin-on deposition
Wet etching
• Isotropic wet etching
• Anisotropic wet etching (single
crystal)
Dry etching
• Vapour etching
• Plasma etching
• Reactive ion etching
Table 2.5 Thin film deposition techniques and etching techniques [Error:
7.1.2. Surface Micromachining
At first glance, surface micromachining may look similar to bulk
micromachining. However, some sharp differences exist between the two
techniques. In bulk micromachining, the three dimensional structure is built by
etching the substrate (e.g. polysilicon or single crystal silicon), whereas in
surface micromachining, the structure is built through layer by layer deposition
(See Fig. 2.19d). Besides this, in surface micromachining, shapes in the XY-
plane are not restricted by crystallography as is the case for bulk processes.
Table 2.6 compares bulk and surface micromachining.
Some of the limitations associated with surface micromachining, as outlined
in Table 2.6, have been overcome by process modification and/or alternative
designs.
7.1.3. LIGA & Micromolding
LIGA is a combination of processes used to manufacture high aspect ratio
microstructures with height in the millimetre range, lateral submicronic precision
and very smooth walls (See Fig. 2.19e-f). Components made of a large variety
of materials can be manufactured; polymers, metals, alloys and ceramics.
LIGA was developed by the Forschungszentrum Karlsruhe. It stands for
LIthographie (lithography), Galvanoformung (electroplating) and Abformung
(moulding), which are the main steps of the process.
The original LIGA process starts with an X-ray lithography on a conductive
substrate coated with PMMA. The cavities are then filled with metal by

electroplating. The resulting metal structure can be used as a tool for ceramic
sintering or plastic replication (hot embossing or injection moulding).
Bulk Micromachining Surface Micromachining
z-dimension restricted by wafer thickness
No annealing needed
Devices can be built from single crystal Si
Can use crystallography for dimensional control
Stiction is not a concern
z-dimension restricted by deposition
technique used
Annealing at high temperatures needed
Only Polysilicon can be used
Crystallography dimensional control at
possible
Surface stiction possibility
Table 2.6 Comparison between bulk and surface micromachining techniques [Error:
a b c
d e f
Fig. 2.19 LIGA & micromolding applications: (a) 3D Micro stereo-lithography
components [40
]; (b) V-grooves by bulk micromachining (anisotropic) [Error:
Reference source not found]; (c) Silicon micro air turbine by bulk micromachining
[41
]; (d) Micro-gripper by surface micromachining [42
]; (e) SU-8 with aspect ratio 
60:1 wall by LIGA [Error: Reference source not found]; (f) SU-8 micro gear by UV
LIGA [Error: Reference source not found].
7.2. Energy assisted processes

Energy assisted processes, similarly called electro-thermal processes, comprise
Laser Beam Machining (LBM), Focused Ion Beam (FIB), Electron Beam Machining
(EBM), Micro Electro Discharge Machining (MicroEDM) and Plasma Beam Machining.
7.2.1. Laser Beam Machining (LBM)
The use of laser technology in processing of materials for micro products has
been reported over the last decade [43
]-[Error: Reference source not found], and
is now used routinely in many industries. Laser beams are used both to remove
material and to join components (heat treatment, welding, ablation, deposition,
etching, lithography, photo-polymerization, etc.) [Error: Reference source not
found].
The use of lasers in micromanufacturing is closely connected to the
characteristics of the laser and depending on that, lasers can be used for a
broad range of materials [44
]. Metals, ceramics, glass, polymers and
semiconductors are the most widely used materials for micro products, and all
of these materials can be processed by one or more laser technologies (see
Fig. 2.21a) [45
].
The parameters such as wavelength, power, pulse duration and pulse
repetition rates are the main ones to be chosen and controlled.
7.2.2. Micro Electro Discharge Machining (MEDM)
Electrical discharge machining (EDM) is a relatively slow manufacturing
process which has traditionally been used to machine unusual designs in hard
and brittle metals. Material is removed (melting and partly vaporization) by high
frequency electrical sparks, which are generated by pulsing a high voltage
between the cathode tool and a workpiece anode. The workpiece and the tool
are submerged in a dielectric fluid [Error: Reference source not found]. The
process requires the workpiece material to be conductive and the hardness is
not critical. Electrodes are usually made from graphite, copper, or even silver
(see Fig. 2.21b).
Typical machining technologies for MEDM are Wire-EDM (WEDM), Sinking-
EDM (SEDM), EDM-drilling, EDM milling and WEDG (Wire Electro Discharge
Grinding). WEDM and SEDM are two major types of EDM.
In the wire EDM process, thin wires with diameters as small as 20µm are
used as electrodes (see Fig. 2.21c). This process is primarily used for producing
2D structures and for manufacturing electrodes [Error: Reference source not
found].
Regarding the SEDM, the manufacture of the electrode is an essential step
since it determines the resulting quality of the manufactured feature. The
electrode tool is shaped in the form of the desired cavity or simple shaped, in
order to avoid the significant wear suffered while machining [46
]. Holes diameters

as small as 5 µm are reported with aspect ratios in the interval of 10-20 [47
-48
],
micro grooves and even complex formed 3D structures [Error: Reference source
not found].
7.2.3. Electron Beam Machining (EBM)
Electron-beam removal of materials is another fast-growing thermal
technique. Instead of electrical sparks, this method uses a stream of focused,
high-velocity electrons from an electron gun to melt and vaporize the workpiece
material.
The electron beam is used to write on an electron-sensitive film or create
surface modifications of materials (see Fig. 2.21d). The basic techniques are
highly developed for IC mask production and are particularly useful for the
production of structured surfaces such as binary optics [49
]. A typical cross-
sectional diameter of the beam is 10 to 200 µm at the point of impact on the
workpiece [Error: Reference source not found].
7.2.4. Focused Ion Beam (FIB)
Some authors classify Focused Ion Beam (FIB) as a pure mechanical
machining technique in which the drill bit is replaced with a stream of energetic
ions though it is not very extended yet. A liquid metal ion source (e.g. gallium) is
used rather than an argon beam, and the ion beam is focused down to a
submicron diameter [Error: Reference source not found].
A principal capability of the dual beam FIB is either the removal or addition of
material (see Fig. 2.20). These processes are assisted through several gas
micro-nozzle injectors with a gaseous material for a locally reactive
environment. Focused ion beam machining is an alternative way of machining
Fig. 2.20 Focused Ion Beam dual beam capability [50
].
fine structures and extremely fine details, even 3D structures with spot sizes
down to 10-50 nm [51
]-[52
], [53
] (see Fig. 2.21e) [54
].

7.2.5. Plasma Beam Machining (PBM)
Plasma spraying is a particle method adapted towards fast deposition of thick
films (>30µm) and in terms of future micromachining applications, the method
might enable the batch fabrication of solid state gas sensors. However, the
technique is currently of marginal use in micromachining (see Fig. 2.21f).
a b c
d e f
Fig. 2.21 Energy assisted processes applications: (a) Micro gearwheel made of sapphire
machined by UV LBM [55
]; (b) Rod, machined by WEDG, diameter: 12 μm [56
]; (c) Die to
extrude polymer for fishing line production using 30 m wire by WEDM [57
]; (d) Filter
body with Ø100 m 3,5 million micro-holes in 316 S/S by EBM [58
]; (e) Bull sculpture
machined in diamond by FIB [59
]; (f) Aero-engine turbine with a thermal barrier coating
by PBM [60
].
7.3. Mechanical processes
Mechanical processes are mainly employed for the direct manufacture of small
numbers of precision parts. These processes comprise micro-cutting processes,
microgrinding and ultrasonic machining.
In mechanical machining, various factors such as deformation of the workpiece and
tool, vibration, thermal deformation, inaccuracies of machine tools, etc., are major
concerns regarding attainable machining accuracy [Error: Reference source not found].
7.3.1. Micro-cutting processes
Micro-cutting processes are characterised by mechanical interaction of a
sharp tool with the workpiece material causing breakage inside the material

along defined paths; eventually leading to removal of the useless part of the
workpiece in the form of chips. In order to realize such a process, the tool
material must be harder than the workpiece material, and no thermally activated
diffusion has to take place between tool and workpiece material [Error:
Most common micro-cutting technologies are diamond turning, diamond
milling, micromilling, diamond drilling and diamond polishing of structures.
Micro-cutting has the advantage that the tools in these processes contact the
workpiece during machining leading to a strong geometric correlation of tool
path and generated surface. The major drawback of processes of this type is
that the machining force may influence machining accuracy and the limit of
machinable size because of elastic deformation of the micro tool and/or the
workpiece [Error: Reference source not found].
Diamond turning
Micro machining is gaining popularity and micro diamond turning is one of the
most suitable machining processes for micro-optical device fabrication [61
].
This process is also known as Single-Point Diamond Turning (SPDT). The
process of diamond turning is widely used to manufacture high-quality aspheric
optical elements from glass, crystals, metals, acrylic and other materials (see
Fig. 2.22). Optical elements produced by the means of diamond turning are
used in optical assemblies in telescopes, TV projectors, missile guidance
systems, scientific research instruments, and numerous other systems and
devices.
Tool alignment is an essential pre-condition for achieving the desired quality
in diamond turning (tilt errors in X-Y, X-Z and Y-Z planes).
Fig. 2.22 Diamond turning [62
].

Fig. 2.23 Diamond milling processes for the fabrication of microstructured
surfaces [Error: Reference source not found].
Diamond milling
In diamond milling, mainly two different types of processes for the generation
of microstructures can be found; circumferential milling, so called fly-cutting (V-
shaped monocrystalline diamond tool), and ball-end milling (Fig. 2.23).
Typical applications of fly cutting are micro prisms and reflective arrays, and
embossing rollers for circumferential milling (see Fig. 2.26a-b).
Micromilling
The micro-cutting of traditionally used materials in manufacturing such as
steel, aluminium, brass, etc. with tungsten carbide tools can meet many of the
demands of miniaturised components (see Fig. 2.26c).
Many micromanufacturing processes lack the ability to structure different
materials from silicon or polymer, and they are not suitable to generate three-
dimensional geometries for small and medium lot sizes. Micromilling is a
promising approach to overcome these limits of common microfabrication
technologies and it will be analysed in detail in Chapter 3.
Diamond drilling
For special applications, diamond turning and milling processes applying
mono-crystalline diamond tools may not be useful due to their geometric and
cinematic limitations. Therefore, diamond contour boring has been developed
for the manufacture of micro structured optical moulds (see Fig. 2.24).
Fig. 2.24 Contour boring with half-arc monocrystalline diamond tools [Error:

a b
Fig. 2.25 Polishing of structures: (a) pin-type tool; (b) wheel-type tool
[Error: Reference source not found].
Polishing
If surface quality of structured high-precision molds for the replication of
optical components is not sufficient to meet the increasing demands concerning
surface roughness, form and accuracy, subsequent polishing of the structured
molds may be necessary (see Fig. 2.25). The feasibility for polishing of
structures has been demonstrated [63
].
7.3.2. Microgrinding
Microgrinding is applied for the manufacture of precision parts made of hard
materials; glass lenses, silicon, ceramic, etc. (see Fig. 2.26d). It can be used for
the fabrication of pins, grooves and micro-cavities with dimensions in the
micrometer range.
Microgrinding has some constraints in wheel size and shape that limits
achievable quality and geometry of micro parts and structured surfaces.
Moreover, difficulty in grinding tool-making and preparation including truing and
dressing also hampers the widespread application of diamond grinding into
micro fabrication significantly.
7.3.3. Ultrasonic Machining (USM)
USM, also called ultrasonic impact grinding, is a method in which a tool and
free abrasives are used. The tool that is vibrated at ultrasonic frequency drives
the abrasive to create a brittle breakage on the workpiece surface. The shape
and dimensions of the workpiece depend on those of the tool. Since material
removal is based on brittle breakage, this method is suitable for machining
brittle materials such as glass, ceramics, silicon and graphite (almost any hard
material) [64
-65
] (see Fig. 2.26e-f).
The major problems are the accuracy of the setup and the dynamics of the
equipment. Ultrasonic vibration of the machining head makes accurate tool
holding difficult [Error: Reference source not found].

a b c
d e f
Fig. 2.26 Mechanical processes applications: (a) Micro-car (L =7 mm, W=2.3 mm &
H=3 mm) and rice grains by diamond machining [66
]; (b) Plastic fresnel lens
replicated from diamond machined moulds for photovoltaic panel [Error:
Reference source not found]; (c) Mould for gearwheel milled in steel by
micromilling [Error: Reference source not found]; (d) Ra<5nm component by
microgrinding [67
]; (e) A micro-hole in quartz glass machined by USM [68
]; (f)
Micro-devices produced by USM [69
].
7.4. Replication techniques
In many manufacturing cases, the final objective is mass production. The
economic mass production of microparts and microstructures is achieved mainly by
replication techniques like Micro-Injection Moulding, hot embossing and micro-casting;
though other forming processes in an incipient stage (cold forging, bending, punching,
deep drawing, extrusion, etc.) are growing rapidly [70
].
7.4.1. Micro-injection moulding
Micro injection moulding is based on heating a thermoplastic material until it
melts, thermostatting the moulds’ parts, injecting the melt with a controlled
injection pressure into the micromould cavity, and cooling the manufactured
goods.
Micro injection compression moulding and thin-wall injection moulding are
two good Micro Injection Moulding candidates for microfabrication [Error:
Reference source not found] (see Fig. 2.27a).
7.4.2. Hot embossing
10mm

The process of hot embossing of thermoplastic polymers involves the plastic
flow of material around a tool that has a shape inverse of the desired part
shape. The material is first heated to a point between the glass transition
temperature (Tg) and the melting temperature (Tl) and then, the tool is pressed
into the material uniaxially [71
]. It takes place in a machine frame similar to that of
a press. The frame delivers the embossing force of the order of 5 to 20 tons.
Hot embossing provides several advantages as compared with micro
injection moulding, such as relatively low costs for embossing tools, a simple
process, and a high replication accuracy for small features. However, it has the
inconvenient with regards to the micro injection moulding of elevated residual
stresses on moulded parts and the capability only for low aspect ratio [Error:
Reference source not found] (see Fig. 2.27b).
7.4.3. Casting
For new product development, an attractive way of rapid prototyping is
casting. This method called soft lithography has been used by many
researchers because of its simplicity (see Fig. 2.27c).
However, the long cycle time and polymerization shrinkage make it difficult
for mass production in most industrial applications [Error: Reference source not
found].
7.4.4. Microforming
The term microforming refers to the shaping technologies (cold forging,
bending, punching, deep drawing, extrusion, etc.), with at least two dimensions
under the millimetre range, particularly appropriate for mass production of
metallic parts. In this field, metal forming takes up quite a special position due to
its well-known advantages of high production rates, minimised or zero material
loss, excellent mechanical properties of the final product and close tolerances
making it suitable for near net shape or even net shape production. Considering
sheet metal working as well as bulk metal forming, the large potential of this
technology to be applied in the microworld is opened up. Typical examples are
the production of leadframes and connector pins (see Fig. 2.27d-e-f).
a b c

d e f
Fig. 2.27 Replication techniques applications: (a) MIM piezosensor [72
] ; (b) Replicated
sol-gel micro-optical elements by hot embossing [73
]; (c) Aluminium casting [74
];
(d) Micro springs and filaments [75
] ;(e) Micro extrusion part in comparison with an ant
(diameter 500 µm / 300 µm, wall thickness of the cup 50 µm) [76
]; (f)Pins used for IC
carriers [Error: Reference source not found].
7.5. Handling, assembly, packaging, quality assurance &
metrology
Manipulation and assembly of micro parts is an issue facing new problems (small
joining tolerances, surface forces dominating effect or even micro-device breakage for
excessive force, positioning errors due to changes in temperature, vibrations or
contamination [56]) that there were not encountered in conventional size production.
Besides this, handling and packaging of micro components is crucial to their
application, and currently makes more than even 80% of the total costs in some
applications [Error: Reference source not found] (see Fig. 2.28a-b).
Regarding quality assurance and metrology, process control is the key to the
successful manufacture of micro scale devices and products. Functional tests of micro
a B c
Fig. 2.28 Handling, assembly, packaging, quality assurance & metrology
applications: (a) Surgical microtool microgripper with a size of two grains of salt
[77
]; (b) Electro Microfluidic Packaging [78
]; (c) 3D Zeiss F-25 CMM 7.5nm
resolution & 250nm uncertainty for 1cm3
volume [79
].
products are important to determine product performance. This implies dynamic testing
under various operating conditions, and the simultaneous monitoring of product
performance.

Standardization in the field of micro technology is required if some sort of unified
language has to be developed. Input from both the MEMS and the precision-
engineering world are necessary in order to define common guidelines regarding
tolerances, measuring instruments as well as measurement and calibration methods
[80
].
Moreover, in the case of small product dimensions, the ratio between surface area
and dimensions causes metrological problems. As product dimensions become
smaller, the ability to distinguish between surface and linear dimension becomes more
difficult. There is a need for instruments capable of measuring real 3D micro products
though a few attempts have been made in this direction (see Fig. 2.28c).
8. FUTURE CHALLENGES
Currently existing idea that microfabrication technologies and microproducts will
have an excellent industrial and commercial acceptance is generalised, and market
expectations reveal an enormous potential.
However, there are some challenges to be faced if more rapid spread, and an
improved acceptance are sought [81
-82
]:
Production capacity. A massive implementation of the microtechnologies in industry
requires the possibility to obtain large batch production of microcomponents at a
reduced cost. In consequence, new manufacturing processes, new machines and other
production means should be developed, or current microtechnologies should be
adapted as well.
Packaging and assembly techniques. The packaging and assembly techniques
allow microsystems to connect with external applications. Existing techniques involve
a significant increase of the final microsystems prices. Thus, more economical and
novel techniques with an easy connection and suitability for aggressive
environmental conditions are required.
New materials. Microsystems requirements vary depending on their application.
Satisfying these needs means using one or another type of material. Generally, the
need to reduce fabrication costs and large batch production of microcomponents,
materials’ biocompatibility, the possibility to work within aggressive environments,
special behaviour over certain physical properties, and other factors demand using
alternative materials to silicon, like polymers, metals, ceramics, composites, etc. or
the development of new materials modifying the internal structure at nanometric
scale.
Specific engineering tools. An adequate microsystem design and simulation
helps to reduce errors and save time and money. The design and simulation tools
should be specific for each fabrication technology and adapted to work with high
precisions and reduced dimensions including appropriate material libraries for
microcomponents considering the scale effect.

Standardization. If a higher acceptance of microsystems is sought, costs and
development time should be reduced. Standardization results in an effective way to
reduce them, increasing the demand to produce microcomponents, overcoming the
economies of scale, and making possible the construction of microsystems by
means of the integration of modular blocks. Industry needs to be active and aware of
standardization matters as well as being effective in getting its standards accepted in
the markets.
Qualified workforce and multidisciplinary teams. An education system capable of
delivering the required diversity and multidisciplinarity in a skilled research, design
and production workforce is needed. It is imperative to note that the increasing
complexity of the technology requires significant multidisciplinary education and
training programmes. Demand is already outstripping the supply of talent.
Infrastructure creation. A research environment and adequate infrastructure
capable of supporting visionary and industrially relevant advanced pre-production
research activities, including validation processes (such as pilot lines), that facilitate
the rapid introduction of innovative technologies into manufacturing systems,
products and services to deliver world-class results in a timely manner should be
constructed.
Financial and institutional support. A favourable legal and financial environment
(including fast-responding regulatory support) would speed-up participation from the
major actors of the critical value chains for the huge and ever-increasing investments
required in the competitive globalised market. Strategic public-private partnerships
should be rewarded, in which strong user industries share their long-term visions
with research partners, and a critical mass of resources is mobilised in the most
coherent possible way.
9. BIBLIOGRAPHICAL REFERENCES

1 [] IC Knowledge, Website: www.icknowledge.com, 2002.
2 [] Bell laboratories, Website: www.bell-labs.com
3 [] IEEE-virtual-museum, Website: www.ieee-virtual-museum.org
4 [] Intel Corporation, Website: www.intel.com
5 [] R. Feynman., There’s plenty of room at the bottom, Journal of Microelectromechanical
Systems, 1 (1):60–66, 1992.
6 [] R. Feynman. Infinitesimal machinery, Journal of Microelectromechanical Systems, 2
(1):4–14, 1993.
7 [] The international technology roadmap for semiconductors, ITRS reports, 2005.
8 [] J. Chae, S.S. Park, T. Freiheit, Investigation of micro-cutting operations, International
Journal of Machine Tools and Manufacture, 46 (3-4):313-332, 2006.
9 [] L. Alting, F. Kimura, H.N. Hansen, G. Bissacco, Micro Engineering, Annals of CIRP 52
(2):635-658, 2003.
10 [] M.J. Madou, Fundamentals of Microfabrication, CRC Press, ISBN 0-8493-0826-7,
2001.
11 [] Mechanical Engineering Laboratory (MEL), Website: www.aist.go.jp,
Japan.
12 [] Programa de Microtecnologias. Investigacion Estrategica. Plan de Ciencia,
Tecnología e Innovación (PCTI) 2001-2004 del Gobierno Vasco.
13 [] Reports on Micro and Nano Technologies, MINATECH European Project, VDI/VDE-IT
GmbH, Germany, 2001.
14 [] EURIMUS II, Eureka Industrial Initiative for Microsystems Uses, Blue Book, Grenoble,
2003.
15 [] NEXUS, Website: www.nexus-mems.com
16 [] M.P. Groover, Fundamentals of Modern Manufacturing 2/e, John Wiley & Sons, Inc,
2002.
17 [] SUSS Micro Tec AG, Website: www.suss.com
18 [] World of Microsystems, 2nd Edition CD-Room, Yole Development, 2000-2003.
19 [] Physikalisch-Technische Bundesanstalt (PTB), Website: www.ptb.de, Germany.
20 [] Microsensors Inc., Website: www.microsensors.com
21 [] B. Choudhary, S. Singh, The bright future of mobile computing. Smartphone & Pocket
PC magazine, 2005.
22 [] B. Mukhopadhyay, A micromachined continuous ink jet print head for high resolution
printing, Microsensor and Actuator Technology (MAT), TU Berlin, 2005.
23 [] SINTEF, Website: www.sintef.no, Norway.
24 [] Virtual Devices, Inc, Website: www.virtualdevices.net, USA.
25 [] S. Hollar, J.K. Perng, K.S.J. Pister, Wireless static hand gesture recognition with
accelerometers - The acceleration sensing glove, Berkeley's Sensor and Actuator Center,
University of California, 2000.
26 [] LAUNCH-MICRO European Project, Website: http://193.146.78.41:8080/lmpro
27 [] D. Erickson, D. Li, Integrated microfluidic devices, Anal of Helvetica Chimica Acta
507:11-26, 2004.
28 [] Dentaurum, Website: www.dentaurum.de, Germany.
29 [] STEAG MicroParts, Website: www.microparts.de, Germany.
30 [] B. Braun Corporate, Website: www.bbraun.com, USA.
31 [] Tekes, Website: www.tekes.fi, Finland.

32 [] P. Althainz, J. Goschnick, S. Ehrmann, H. J. Ache, Multisensor microsystem for
contaminants in air, Karlsruhe Micronose, Sensors and Actuators B, 33:72-76, 1996.
33 [] D. Culler, D. Estrin, M. Srivastava, Overview of sensor networks, IEEE Computer
Society 37 (8):41–49, 2004.
34 [] STEAG microParts, Website: www.steag-microparts.de
35 [] FingerTIP Infineon, Website: www.infineon.com
36 [] S.T. Smith, Meso systems considerations, M4 Workshop on Micro/Meso Mechanical
Manufacturing. Centre for Precision Metrology, Northwestern University, USA, 2000.
37 [] E. Brinksmeier, O. Riemer, R.Stern, Machining of precision parts and microstructures,
Proc. 10th International Conference on Precision Engineering (ICPE), Japan, 2001.
38 [] T. Masuzawa, State of the art of micromachining, Annals of CIRP 49:473–88, 2000.
39 [] C. Liu, Foundations of MEMS, ISBN 0-13-147286-0, Publisher: Prentice Hall,
University of Illinois at Urbana-Chapaign, 2006.
40 [] R. Lawes, M4 technology Microsystems Event, Council for the Central Laboratory of
the Research Councils (CCLRC), 2003.
41 [] M. Esashi, K. Minami, T. Ono, Silicon bulk micromachining and nanomachining,
Condensed Matter News 6:31-44, Tohoku University, Japan, 1998.
42 [] C.G. Keller, R.T. Howe, Hexsil tweezers for teleoperated micro-assembly, IEEE Micro
Electro Mechanical Systems Workshop, p. 72-77, 1997.
43 [] M. Gower, N. Rizvi, Applications of laser ablation to microengineering, Proc. of SPIE,
High-power laser ablation III 4065:452-460, 2000.
44 [] H.K. Tönshoff, A. Ostendorf, S. Nolte, G. Kamlage, T. Wagner, F. Korte, T. Bauer, New
applications of femtosecond lasers in micromachining, Proceedings of the 1st Euspen Topical
Conference on Fabrication and Metrology in Nanotechnology, p. 10-17, Denmark, 2000.
45 [] J. Meijer, K. Du, D. Hoffmann, V.S. Kovalenko, A. Ostendorf, R. Poprawe, W. Schulz,
Laser machining by short and ultrashort pulses, state of the art and new opportunities in the
age of the photons, Annals of the CIRP 51(2):531-550, 2002.
46 [] Z.Y. Yu, T. Masuzawa, M. Fujino, Micro-EDM for three-dimensional cavities –
development of uniform wear method, Annals of the CIRP 47(1):169-172, 1998.
47 [] Z.Y. Yu, K.P. Rajurkar, H. Shen, High aspect ratio and complex shaped blind micro
holes by micro EDM, Annals of the CIRP 51(1):359-362, 2002.
48 [] Y. Li, M. Guo, Z. Zhou, M. Hu Micro electro discharge machine with an inchworm type
of micro feed mechanism Precision Engineering, 26: 7-14, 2002.
49 [] C.J. Evans, J.B. Bryan, , “Structured”, “Textured” or “Engineered” Surfaces, Annals of
the CIRP, 48 (2):541-556, 1999.
50 [] Fibics incorporated, Website: www.fibics.com
51 [] D.P. Adams, M.J. Vasile, G. Benavides, A.N. Campbell, Micromilling of metal alloys
with focused ion beam-fabricated tools, Precision Engineering 25:107-113, 2001.
52 [] D.P. Adams, M.J. Vasile M.J., Krishnan A.S.M., 2000, Microgrooving and
microthreading tools for fabricating curvilinear features, Precision Engineering 24:347- 356.
53 [] F. Morrissey, Micro and nano structuring using focused ion beam and dualbeam
technolgies, Proc. of the 3rd Euspen International Conference, Netherlands, p. 475-478, 2002.
54 [] S.D. Senturia, Microsystem design, ISBN 0-306-47601-0, Kluwer Academic
Publishers, USA, 2001.
55 [] E. Brinksmeier, O. Riemer, Metal Cutting of Microstructures. International Conference
on Multi-Material Micro Manufacture (4M), Germany, 2005.
56 [] Institut für Produktionstechnik (WBK), University of Karlsruhe, Website: www.wbk-
ka.de
57 [] Manufacturing Engineering Centre (MEC), Cardiff University, Website:
www.mec.cf.ac.uk

58 [] Acceleron, Inc, Website: www.acceleron-enbeam.com
59 [] Norsam Technologies, Inc., Website: www.norsam.com
60 [] TWI Ltd., Website: www.twi.co.uk
61 [] H.S. Lim, M. Rahman, Design and development of a fast tool servo for micro lathe,
National University of Singapore.
62 [] J. Fleischer, Manufacturing of Micro Moulds by Conventional and Energy Assisted
Processes, International Conference on Multi-Material Micro Manufacture (4M), Germany,
2005.
63 [] E. Brinksmeier, O. Riemer, A. Gessenharter, L. Autschbach, Polishing of Structured
Molds, Annals of the CIRP 53(1):247, 2004.
64 [] K. Egashira, T. Masuzawa, M. Fujino, X. Sun, Application of USM to Micromachining
by On-the-machine Tool Fabrication, International Journal of Electrical Machining 2:31-36,
1997.
65 [] K. Egashira, T.Masuzawa. Microultrasonic Machining by the Application of Workpiece
Vibration, Annals of the CIRP 48(1): 131-134, 1999.
66 [] A. Teshigahara, M. Watanabe, N. Kawahara, Y. Ohtsuka, T. Hattori, Performance of a
7-mm microfabricated car, Journal of Microelectromechanical Systems 4:76-80, 1995.
67 [] Cranfield University, Website: www.cranfield.ac.uk.
68 [] K. Egashira, K. Mizutani, Ultrasonic Vibration Drilling of Microholes in Glass, Annals of
the CIRP 51(1):339-342, 2002.
69 [] Bullen Ultrasonics, Inc., Website: www.bullen-ultrasonics.com
70 [] M. Geiger, M. Kleiner, R. Eckstein, N. Tiesler, U. Engel, Microforming, Annals of the
CIRP 50(2):445-462, 2001.
71 [] D. Hardt, B. Ganesan, W. Qi, M. Dirckx, A. Rzepniewski, Process Control in Micro-
Embossing: A Review, Innovation in Manufacturing Systems and Technology (IMST)
Collection, Massachusetts Institute of Technology, 2004.
72 [] Miniature Tool and Die Inc., Website: www.miniaturetool.com
73 [] Centre Suisse d'Electronique et de Microtechnique SA (CSEM), Website:
www.csem.ch
74 [] Sigma Time Compression Technologies (TCT), Website: www.sigmatct.com
75 [] WAFIOS Aktiengesellschaft, Website: www.wafios.de
76 [] Lehrstuhl für Fertigungstechnologie (LFT), Erlangen, Germany, Website: www.lft.uni-
erlangen.de
77 [] Livermore National Laboratory’s Microtechnology Center, Website: www.llnl.gov
78 [] D. Erickson, D. Li, Integrated microfluidic devices, Analytica Chimica Acta 507:11-26,
2004.
79 [] Carl Zeiss Inc., Website: www.zeiss.com
80 [] R.K. Leach, The importance of metrology and standardisation for micro-systems
technology, National Physical Laboratory, UK. 2002
81 [] Microtecnologías y Microsistemas. Tendencias tecnológicas a medio y largo plazo.
OPTI Fundation, 2003.
82 [] Vision 2020, Nanoelectronics at the centre of change. European Commission. Report
of the High Level Group, 2004.

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