| Embedded capacitor technology can increase silicon packing efficiency, improve electrical performance, and reduce assembly cost compared with traditional discrete capacitor technology. Developing a suitable material that satisfies electrical, reliability, and processing requirements is one of the major challenges of incorporating capacitors into a printed wiring board (PWB). Polymer-ceramic composites have been of great interest as embedded capacitor material because they combine the processability of polymers with the high dielectric constant of ceramics. A novel nano-structure polymer-ceramic composite with very high dielectric constant (ϵr ∼ 150, a record for the highest reported ϵr value of the polymer ceramic nano composite) has been developed in this work. High dielectric constant is obtained by increasing the dielectric constant of the epoxy matrix (ϵr > 6) and using the combination of lead magnesium niobate-lead titanate (PMN PT)/barium titanate (BaTiO3) as ceramic filler. This nano-composite has low curing temperature (<200°C), thus it is multi-chip-module laminate (MCM-L) process compatible. An embedded capacitor prototype with capacitance density of 35 nF/cm2 has been manufactured using this nano-composite and spin coating technology. This novel nano-composite can be used for embedded capacitors in PWBs. In order to overcome the poor adhesion of the polymer ceramic composite, an ultra high dielectric constant epoxy silver composite was developed. This novel material has a very high dielectric constant (ϵ r > 2000), low dielectric loss and excellent mechanical properties. Investigations have been conducted to study the silver flake effect, gold flake effect, photo definability and dielectric loss control of the polymer metal composite. Embedded capacitor was demonstrated on flexible substrate using the high K epoxy silver composite.; The design of embedded passives is very important to its practical application. However, there is still no mature commercial CAD tool available for embedded passive design. Computer simulation and modeling have been conducted for embedded capacitors and resistors. The commercial finite element software was used for the modeling work, which includes thermal tolerance analyses, and the electric interference prediction of embedded capacitor. Attention was given to the effects of material properties and the geometry of the embedded passives. Finite element method (FEM) model provides a good picture about the distribution, electric performance and tolerance of embedded passives. This FEM simulation is very helpful for the design and manufacture. |
