Design and Fabrication of MEMS Based Microphone Module by Using 3D Chip-on-Chip Package Available to Purchase

Packaging of the MEMS based microphone is very important as the sensing diaphragm is very fragile. A suitable packaging method is required for the MEMS based microphone. In order to have a better understanding of packaging related issues of microphone, commercially available MEMS based microphone package is studied. Based on the preliminary study, a 3D Chip-on-Chip modulus is selected. The detail process flow of the mentioned package will be discussed in the following sections. Flip chip with lead free solder bumps are used in the proposed 3D Chip-on-Chip modulus. In contrast, wire bonds are used in the commercial MEMS based microphone for electrical connections while die attached is used to provide the mechanical support. The advantages of using flip chip over wire bond in both manufacturability and reliability aspects are discussed. Several MEMS based microphone packaging related issues are studied and evaluated. The detail fabrication and assembly process flow will be presented. A prototype package with MEMS device is fabricated. It can be shown that the proposed 3D Chip-on-Chip modulus is feasible for packaging MEMS based microphone.