The main objective of my research project is the development of an innovative method of dielectric constant reduction with the use of controlled internal porosity in LTCC structures. For this purpose, an experimental glass-ceramic green tape (doped with starch as pore former) was created.

1. Reduction of dielectric constant of LTCC
with useof controlled porosity
BeataSynkiewicz
PBSResearch Project - ActiSkan

2. ∗ To examine the effect of controlled porosity on LTCC
parameters, two experimental glass-ceramic powders were
performed.
∗ First composition based on glass type E with low content of
alkali substrates (mainly SiO2, Al2O3, CaO, B2O3) and on Al2O3
ceramics.
∗ Second composition was created basing on first one but
doped in a weight ratio of 1:1 with starch powder (for porosity
obtainment during co-firing process).
∗ Glass ceramic powders were a basis for slurries, which in the
next step were tape casted to get LTCC green tapes.
METHODOLOGY

3. ∗ During co-firing (in 900 °C), starch component was
burnt out with other organic ingredients, leaving
empty spaces in the structure. The sintered samples
were of good quality, without deformations and
delamination.
EFFECT OF CO-FIRING
∗ The porosity is shown on
SEM images of material
cross-section
∗ 1. Cross-section of LTCC multilayer structure
made of glass-ceramic tape with porosity
caused by graphite (SEM images)
2. The structures after co-firing
1
2

4. ∗ For examination of
electric permittivity, in
the final step, silver
electrodes were manually
printed at both sides of
experimental samples.
The parallel capacitance
was measured at
frequency of 1 KHz -2 MHz
(in room temperature)
using RLC Quad Tech
device. In the next step,
dielectric constant was
calculated.
RESULTS

5. ∗ The percentage decrease of dielectric constant after applying
a 50% admixture of starch powder in the internal layers of the
LTCC, was about 56%.
∗ Application of non-porous glass-ceramic covers resulted in
greater mechanical strength of the structure and its smooth
surface, allowing printing with conductive paste at both sides
of the sample
CONCLUSIONS

6. ∗ The percentage decrease of dielectric constant after applying
a 50% admixture of starch powder in the internal layers of the
LTCC, was about 56%.
∗ Application of non-porous glass-ceramic covers resulted in
greater mechanical strength of the structure and its smooth
surface, allowing printing with conductive paste at both sides
of the sample
CONCLUSIONS