Flip-Chip Assembly of RF MEMS for Microwave Hybrid Circuitry Available to Purchase

XCom Wireless is a small business specializing in RF MEMS-enabled tunable filters and phase shifters for next-generation communications systems. XCom has developed a high-yielding flip-chip assembly and packaging technique for implementing RF MEMS devices into fully-packaged chip-scale hybrid integrated circuitry for radio and microwave frequency applications through 25 GHz. This paper discusses the packaging approach employed, performance and reliability aspects, and lessons learned. The packaging is similar to a hybrid module approach, with discrete RF MEMS component dies flip-chipped into larger packages containing large-area integrated passives. The first level of interconnect is a pure gold flip chip for high yield strength and reliability with small dies. The use of first-level flip-chip and second-level BGAs allows the extremely large bandwidth MEMS devices to maintain high performance characteristics.