Process development for MMIC based RF modules for reliable and better performance

This article describes parameter optimization of novel packaging techniques for packaging of MMIC dice in aluminium housings. The developed packaging processes are implemented in aerospace modules for overcoming various challenges. The MMIC die is hermetically sealed and interconnected to the microstrip lines on alumina substrate. RF & DC feedthrus are soldered to aluminium housing to provide hermetic electrical I/O connections to MMICs. Thermosonic ribbon bonding process is used to interconnect the ribbon to MMIC die. The ribbon bonding process parameters are optimized to achieve required pull strength. The wire and ribbon effects on insertion loss are measured practically and compared. Also, RF connectors are ribbon bonded to 50 Ω lines as compared to conventional soldering process. Parallel gap welding technique is used for ribbon interconnection on RF connector pin. The developed processes are qualified and used in RF modules of aerospace systems.