Process and Modelling Aspects of Polyimide Over Silicon for RF Circuits Realization and its Implementation

The integration of RF circuits with CMOS on the same substrate is challenging and imposes lot of constraint in practical realization due to inherent losses associated with silicon Si substrate. Various mitigation techniques are proposed to overcome the same which are either process intensive or introduces multiple deleterious effects at RF frequencies. Polyimide is used both in microelectronics and MEMS industry as it can act both as a photo-resist and also having key dielectric properties. The processes presented with polyimide are standard and can be easily integratable with the existing CMOS processes. Fabrication steps and simulation study of the band pass filter topologies over polyimide are presented and the same are fabricated with the proposed process steps. Further this article details the modelling, theoretical aspects, various process steps and actual implementation with the realization of the band pass filter topology using the proposed methodology.