Research On Key Technology Of MEMS Wafer Level Vacuum Packaging Based On TSV

MEMS (Micro Electro Mechanical System) is a micro system that integrate micro mechanical element, micro sensor, micro actuator and signal processing&control circuit. Many MEMS devices, like accelerometer, gyroscope and resonator, need vacuum packaging in order to reduce the damping of mechanical part moving, improve quality factor and increase property of device as well. However, development in MEMS vacuum packaging at home and abroad is not mature. So MEMS vacuum packaging is a project that in dire need to be researched on. TSV (Through Silicon Via) is a new interconnected technology that used in high density 3-dimensional packaging. A new structure and technique of MEMS vacuum packaging is proposed. TSV technique is used in MEMS wafer level vacuum packaging based on the need of wafer level vacuum packaging and characteristics of TSV. The detailed contents for this article are as follows:(1) TSV technology used in MEMS wafer level vacuum packaging is proposed.(2) According to the project need, the characteristics of several wafer bonding processes are compared. The structural design, process design and mask pattern design of Au-Si bonding scheme are completed. The processes of lithography, cavity etching and Au-Si bonding are completed as well. The Au-Si boding process parameters are optimized by multiple tests.(3) The characteristic of TSV is researched. TSV process design is completed based on the need and particularity of MEMS wafer level vacuum packaging. The processes of TSV technique including through-hole etching, insulating layer manufacture, metal film deposition and electroplating filling are completed as well, and the electroplating filling process parameters are optimized by multiple tests.(4) A scheme using film resistor (pirani gage) is propounded to resolve the problem of vacuum changes inside package and real Time monitoring. The dimension of pirani gage is received by structural design and calculation. Pirani gage manufacture and the research on characteristics of pirani gage are completed.(5) The vacuum packaging quality of this article are tested and evaluated, including leakage rate test (including rough test and accurate test) and bonding strength test.