Application of plasma cleaning process in MEMS filter micro-assembly

To solve the problems of low efficiency and high void rate in the process of the MEMS filter (die) attach and increase the strength of wire bonding between the die and microwave circuit board, plasma cleaning process was introduced in the micro-assembly process of the MEMS filter switch module. The spreading area of the solder melted on the copper was analyzed before and after the plasma cleaning process. Process parameters including plasma flow, radio frequency time and radio frequency power were optimized by the orthogonal test. It is demonstrated that the plasma cleaning process is effective to decrease the void rates in die attach and enhance the wire bonding strength, thus improve the reliability of the MEMS filter module micro-assembly.