Study On Silicon-based Embedded Microwave Multichip Module Package

Over the past few years, MMCMs (Microwave Multichip Module) have been more and more widely used in various applications of wireless communication. MMCMs integrate several MMICs (Microwave Monolithic Integrated Circuit) in a single package to form a complete microwave module, and thus, have much higher efficiency in dimension, functionality, usability and maintainability than previous microwave systems assembled with first-level packaged MMICs. Modern communication systems have forced MMCMs to implement stronger functions and endure higher power. Meanwhile, the permitted size of MMCM package gets increasingly and incredibly small with the rise of working frequency. So, a main task people face in MMCM area is to design good package structures and procedures, so that they can not only meet the needs of high calorific, mechanical and electric performance, but also reduce the package size while enhance functionality. Conventional MMCM package technologies are usually base on techniques like single-layer or multi-layer ceramic substrates, wire-bonding or flip-chip as chip-to-package interconnects, thick or thin film and flexible materials as dielectrics. Although those technologies show some extent of excellence in some kind(s) of performance, they do have defects in at least one of the following aspects—heat-sinking, microwave performance, ease of fabrication and cost. Silicon is one of the best heat-conducting and etchable substrates that can be used to enhance heat-sinking and process compatibility with IC technology. BCB/Au multilayer transmission lines are ultra low-lost interconnects that can serve to raise microwave performance of MMCM packages. Based on those two points, two kinds of silicon-based embedded MMCM package (SBEMP) structures are raised in this paper, which can well combine the excellence of those .First, two SBEMP—front-SBEMP and back-SBEMP are introduced concerned with its whole performance. Then, main fabricating processes of SBEMP are discussed and major parameters of them are studied. Last but not least, microwave performance of signal-conducting paths in package is studied with 3D-electromagnetic simulation and experiments, and bandpass filters that can be integrated in package are also studied.