Evaluation of a low-temperature fabrication technology for silicon-ceramic composite substrates

We evaluate a low-temperature fabrication process of silicon-ceramic-composite substrates that is dry film photoresist based interlayer film set between the silicon and the ceramic substrate. Adequate adhesion to silicon as well as to low-temperature cofired ceramics (LTCC) together with the existing long-term experience render polymeric photoresists as intriguing interlayer bond film. Due to their superior film thickness homogeneity and the fact that pre-defined surface features can be effectively balanced, we utilized in our study the commercial dry film photoresists Ordyl FP 415 and Ordyl SY 330. We fabricated in this regard successfully silicon-ceramic composite substrate that fully enabled UV-laser photolithography as well as plasma dry etching of silicon structures. We discuss furthermore, aspects of the utilized thermal treatment procedure comprising parameters like the interface bond strength as well as the wafer bow, the possibilities and limitations of an interface patterning and the overall long-term stability in wet and dry environment.