2. Outline
• Introduction
• LTCC (Low Temperature Cofired Ceramics)
– LTCC materials
– LTCC Passive integration
– LTCC feature forming
– Zero shrink tape: ideal way for integration?
• LTCC Applications
– Wireless
– Automotive, energy and others
• Summary
Steve Dai, SICCAS LTCC Seminar 7_16_2007
3. Introduction
Why Passive Integration?
• Device miniaturization
• Greater component density for increased functionality
• High speed signal process requires
– Lower equivalent series inductors
– Tighter control of parasitic R, C and L
• Higher assembly yield
• Lower system cost
• Better reliability
* Robert Heistand, ED Online #2718, Feb 2, 2003
Steve Dai, SICCAS LTCC Seminar 7_16_2007
4. Introduction
Paths to Passive Integration – technologies
Characteristics PCB (Printing LTCC Thin film on
Circuit Board, (MCM-C) Si/glass
MCM-L) (MCM-D)
Substrates FR-4, BT, FR-5 Ceramic Si, Glass, Sapphire
Dielectric Constant (εr) 4.9 / 3.9 / 4.7 7 -12 12 / 5 / 10
Loss Tangent (1 GHz) .015 /.009/.010 .0003 -.003 .005/ .003 / .0001
Thermal σ(W / m-K) .2 -.4 2.5 100 / 1.7 / 42
CTE (ppm) 15 / 15 / 13 6 2.6 / 1 / 8
# of Layers 8 30 6
Conductors Cu Ag, Ag/Pd, Au, Pt, Cu Al, Cu, Au
Electrical ρ (10-8 Ω-m) 1.7 1.2~1.7 2.6 / 1.7 / 2.1
Thermal ρ (W/m-K) 398 398~428 247~398
Line Width (μm) 100 75 5
Process Variation 10 -15 % 2 –4 % 2 –4 %
RF Frequency < 10 GHz <25 GHz < 50 GHz
# Iterations to Spec 5 5 5
Iteration Time 1 week 2 weeks 2-4 weeks
Iteration Cost1 $.5 K $2 K $10 K
* From INEMI
Steve Dai, SICCAS LTCC Seminar 7_16_2007
5. Introduction
Paths to Passive Integration – a comparison
Technology Integration Advantages Disadvantage
method
Thin film on Lithographically defined
L/C/R
Precision L/C/R value Low inductance
High tolerance Equipment costly
Si/glass Sequential build up of High component density Limited selection on film
layers
(MCM-D) Cost effective for dies < materials
20 mm2 Materials compatibility
Thick film on Screen printed L/C/R on
sintered ceramic
Low cost process No precise Rs
High packaging density Ls difficult to form
ceramics substrates (e.g. Al2O3) Module reliability - auto Process time and yield
Sequential build up of
(MCM-C) multiple layers
applications due to sequential
buildup
PCB (Printing Discrete L/C/R buried in
laminated structure
Low cost process Lack high K dielectric
Multilayer structure R limited, trimming
Circuit Board, Sequential or parallel Cu conductor PCB not RF friendly
MCM-L) process No CAD tool for PCB
passive layout
LTCC Screen printed L/C/R on
“green” ceramics tapes
Parallel layer process Cofireability of materials
High layer counts~ 100 No high K dielectric
(MCM-C) Parallel multi layer and RF friendly materials No precise Rs
final cofired structure Module reliability Inductor limited
* Robert Heistand, ED Online #2718, Feb 2, 2003
Steve Dai, SICCAS LTCC Seminar 7_16_2007
6. Introduction
LTCC market potential
* From Paumonok, in millions of US$
LTCC market driven by RF wireless applications
– Loss conductors, Ag
– Temperature stable base dielectric, Tf ~ 0 ppm/°C
– Precision stack capacitor – resonator
– Fast turn around
– Infrastructure
– Competitive cost
Steve Dai, SICCAS LTCC Seminar 7_16_2007
9. Common LTCC Base Dielectrics
Steve Dai, SICCAS LTCC Seminar 7_16_2007
10. LTCC Base Dielectric
a comparison
Green Sintered
Type 1:
Unreactive, glass as bonding
agent
Example: DuPont 951
Type 2:
Re-crystallizeable, glass re-
crystallize to form high Q
phases
Example: Ferro A6
Type 3:
Reactive, glass as both bonding
agent and ingredients for high
Q crystalline phases
Example: Motorola T2000
Glass Al2O3 Crystalline phase
Steve Dai, SICCAS LTCC Seminar 7_16_2007
12. T2000 TEM Microstructure
Al2O3 particles from 3 μm to <1 μm High Q phases formed in reaction
Al2O3 dissolves/diffuses into glass Particle size/S.A.
Sintering T and t
Heating rate
Steve Dai, SICCAS LTCC Seminar 7_16_2007
13. T2000 Temperature Stability
1.006
T f Measurement
1.248 Tf Measurement
1.246 TiO 2 added 1.004
Resonant frequency (10 9 Hz)
No TiO 2
1.244
Normalized Frequency
1.002
1.242
1.000
1.24
1.238
T f =4.2 ppm/°C 0.998 T2000: 0.6 ppm/C
1.236 FerroA6: -48 ppm/C
T f =-78.5 ppm/°C DuPont 943: -58 ppm/C
1.234 0.996 DuPont 951: -69 ppm/C
Hereaus: -76 ppm/C
1.232
-40 -20 0 20 40 60 80 0.994
Temperature (°C) -50 -30 -10 10 30 50 70 90
Temperature (C)
Compensation of Tf (temp coef of resonant freq):
Need negative Tk material, TiO2 (TK =-750 ppm/°C)
Tf= -(1/2)Tk - α, α is thermal coefficient of expansion
Tf of T2000 is -80 ppm/°C without compensation
Can be continuously tuned near 0 ppm/°C
Steve Dai, SICCAS LTCC Seminar 7_16_2007
15. LTCC Passive Integration
Embedded high K dielectrics
BZN Cofired in LTCC
BZN high K dielectric
Ag
Dielectric properties of low fire BZN K80
T2000
“Higher K Low Loss Dielectric Ceramic Cofireable with a Commercial LTCC Tape System”,
Weiming Zhang, J. Thomas Hochheomer, Christina Modes, Peter Barnwell and Steve Dai, IMAPS
annual meeting, Oct. 2001, Baltimore, USA. To be published on IMAPS proceedings.
10 μm
Critical:
Lower sintering from 1050 to 850 C with 0.5~3.0 wt%
glass
Steve Dai, SICCAS LTCC Seminar 7_16_2007
16. LTCC Conductors
Common conductors and Ag/Pd paste
20
15
Observation
Dimentional Change (%)
10
• Glassy sintered surface 5
with mixed Ag/Pd 0
conductor -5
Dieletric
• No surface glass -10 Ag/Pd alloy
Ag/Pd mixture
observed with alloy -15
* courtesy T. Garino - Sandia National Labs, Albuquerque, NM
Ag/Pd -20
300 350 400 450 500 550 600 650 700 750 800 850 900 950
Temperaure (°C)
Ag: 962 ºC Pd: 1772 ºC
Unusual large expansion in
Ag/Pd mixture in 350-400 ºC.
Kirkendall Effect?
Steve Dai, SICCAS LTCC Seminar 7_16_2007
17. LTCC Passive Integration
Embedded resistor
RuO2 based
Screen Direct
embedded resistor
print write
to
Dielectric properties of low fire BZN
t
P. Yang, D. Dimos, M. A. Rodriguez, R. F.
Huang, S. Dai, D. Wilcox., MRS Proc 542 (1999)
Steve Dai, SICCAS LTCC Seminar 7_16_2007
19. LTCC Passive Integration
integrated magnetic materials
HeraLock with cofired ferrite A. Feingold, et al., IMAPS 2001
transformer, F. Lautenhiser and E.
Amaya, ICAPS 2002
Steve Dai, SICCAS LTCC Seminar 7_16_2007
20. LTCC Integration
piezoelectric/piezoresistive Materials
PZT/LTCC membrane, W. Hermel, P. Otschik, A. Schonecker, Fraunhofer IKTS, Dresden
Piezoresistive pressure sensor on LTCC membrane for integrated pressure
LTCC. Sensitivity: 1.3 mV/kPa sensor, L Golonka, Wroclaw University
Steve Dai, SICCAS LTCC Seminar 7_16_2007
21. LTCC Passive Integration
Status
Embedded L Embedded C Cofired R
(5 ~ 200 nH)
Paste Layer Embedded Surface
(up to 25 (50~70 (10 Ω/sq ~ trimmable
nf/cm2 with pf/cm2) 100 kΩ/sq) (10 Ω/sq ~ 1
K800) MΩ/sq)
± 5% ± 30% ± 5% ± 30% ± 2%
Steve Dai, SICCAS LTCC Seminar 7_16_2007
24. LTCC Feature Forming
microchannels
Sintering cavity without fugitive material M. R. Gongora-Rubio et
al.,Sensors and Actuators
(2001)
Compensate sagging with supported structure
Integrated UV Light Source
Controlled firing of fugitive carbon black paste
Dia. =150 μm V
Thickness = 110 μm
Gas: Ne G. Eden, B. Vojak, Univ. of
V = 100- 200 V Illinois, Urbana, Illinois,
(Courtesy of T. Garino, Sandia) I = 2 mA
Steve Dai, SICCAS LTCC Seminar 7_16_2007 Pressure = 200-800 Torr
25. LTCC Feature Forming
suspended structure
Antennae
Suspended Inductors
1 mm
Unfired 1 mm
Fired
K. A. Peterson et al., CICMT (2005)
Steve Dai, SICCAS LTCC Seminar 7_16_2007
26. LTCC Feature Forming
released moving parts
Pneumatically driven functional-as-
released wheels (3 mm)
Setter as fugitive
materials
K. A. Peterson et al., CICMT (2005)
Wheel free to
rotate
Steve Dai, SICCAS LTCC Seminar 7_16_2007
27. LTCC Feature Forming
Unconventional Forming and Physical Insertion
Ion Mobility Spectrometer Heated gas feed tube
Rolled IMS drift tube
1 cm
Thermistor
Contact
buried
heater
12 mm I.D.
K. A. Peterson et al., CICMT (2005)
(Courtesy of K. A. Peterson
and K. B. Pfeifer, Sandia)
Steve Dai, SICCAS LTCC Seminar 7_16_2007
28. Zero-shrink LTCC Tape
transfer tape
Al2O3 tape Al2O3 tape Al2O3
LTCC Module Sinter LTCC Module LTCC Module
removal
Al2O3 tape
Al2O3 tape
Compatible lamination process
Limited LTCC layers
Require backend Al2O3 removal from surface
Post fire surface electrode patterns
Steve Dai, SICCAS LTCC Seminar 7_16_2007
30. Zero-shrink LTCC Tape
Heralock HL2000 (courtesy of Hereaus)
Full ground plane
Needs no extra processing
Virtually zero x & y shrinkage
Very precise dimensional control
Fires flat
Cavities readily available
Allows novel structures
Steve Dai, SICCAS LTCC Seminar 7_16_2007
31. LTCC Applications
RF building blocks
ANT
C7
C8
Z1
Multilayer Capacitor
Z4
C1 Z2 D1 Z3 C4
TX RX
Vertically Coiled C2 C3 D2
C5
Transmission Line BIAS
C6
Metal
Dielectric Paste Metal
Horizontally Coiled
Dielectric Tape Transmission Line
Dielectric Paste Capacitor
Steve Dai, SICCAS LTCC Seminar 7_16_2007
33. LTCC Applications
Wireless modules
IMST radar sensor IMST transceiver
module
RF moduels, Micro Systems Kyocera PA module – size reduction via passive
Engineering GmbH integration
Steve Dai, SICCAS LTCC Seminar 7_16_2007
34. LTCC Applications
automotive – slow yet stable growth
Bosch electronic turbo charger
• working temperature up to
155°C
• high vibration stress up to 50g
• direct engine mountability
• high packaging density (Thick
Film -> LTCC)
Delphi Delco LTCC ABS controller Delphi Delco LTCC ECU
Steve Dai, SICCAS LTCC Seminar 7_16_2007
35. LTCC Applications
Direct Methanol Fuel cell Concept for Fuel Cell with integrated
pumping and control
Gold
Flow Field Current Air Holes
(anode side) Collector (cathode side)
Working Fuel Cell
Steve Dai, SICCAS LTCC Seminar 7_16_2007
Assembled Fuel Cell
36. LTCC Applications
Micro cooling
Heat pipes Heat spreader
layout of microchannels
grey: line + printed resistor,
black: cooling channel)
Microchannel cooling
Heat pipes formed with LTCC micro channels as heat spreader (Kinzy Jones,
FIU) (H. Thust, Ilmenau TU)
Steve Dai, SICCAS LTCC Seminar 7_16_2007
37. LTCC Applications
Optoelectronic packaging
WAVEGUIDE
Demodulator IC
Input/Output
Integrated laser and
optical modulator
ELECTRICAL
Input/Output
Embedded optical Photo detector
switches
Coax cable
Polyme r optical
waveguide embedded in
LTCC
LTCC Fibre
alignment
groove
Ball grid array mounting Transimpedance
amplifier (flip chip)
Photo detector array MEMS package with integrated
Embedded passives
heaters and thermistors (L.
Silicon V-groove (resistors/capacitors) Golonka, Wroclaw U.)
Multilayer LTCC
Fibre Optic
Input/Output substrate
CMAC’s System In a Package Vision
Steve Dai, SICCAS LTCC Seminar 7_16_2007
38. Summary
LTCC is powerful platform integration technology with wide applications
Wireless applications is the fastest growth area
Material challenges:
Base and integrated high K Dielectrics
Improved Conductors (Au, Ag, Ag/Pd, Pt, Cu, etc)
Precision cofired resistors
Magnetic materials
Functional materials (Ferroelectric, piezoelectric, magnetic, sensing, …)
Process Challenges
Combination of tape and thick film processes
Thin film process for fine feature forming
Interconnect technologies
Modeling on sintering of dissimilar materials
Integration and Assembly Challenges
Application driven
Technologically innovative
Knowledge-based understanding
Steve Dai, SICCAS LTCC Seminar 7_16_2007
39. Backup slides
Methanol Reformer
Cell Phone
Receiver
15 mm
fuel integrated
ENERGY reformers modules
5 mm
MICROSYSTEM WIRELESS
Direct FUNCTIONS on-chip COMMUNICATIONS
Methanol power
Fuel Cell ICs amplifiers
sensors
fuel NEW
Micro Hollow Cathode cells MATERIALS & filters
8 mm
Discharge (MHCD) PROCESSES
light pumps
UV light source
sources 8.5 mm
Power Amplifier
temperature chemical
reactors PCR
E-chip control Pumping/
Mixing
V cell sorting
Integrated BioChip
Technology LIFE DNA
Steve Dai, SICCAS LTCC Seminar 7_16_2007 SCIENCES amplification
40. Backup slides
~
~
LNA Bypass
Impedance Power and Bias Capacitors Bandpass Filter
Matching
Line
To
Bias Amplifier
Circuit
Trap From
Filter Amplifier
1 cm X 1 cm
Switch w/
Harmonic 41 components/sq. cm
Filter To Mixer
Switch Image Reject Filter
Transmit Antenna Bias
Steve Dai, SICCAS LTCC Seminar 7_16_2007
