Study On Silicon Piezoresistive Pressuresensor Packaging

In order to solve problems about chip bonding defects, device structure deformation, uneven distribution of stress, stress that created by packaging is not isolated sufficiently, temperature drift and other issues in pressure sensor packaging process, plastic packaging and metal isolated packaging of silicon piezoresistive pressure sensor are researched through calculation of the pressure sensor theory, finite element analysis of packaging process to influence the size and distribution of the pressure sensor stress, material object test and comparative validation and other methods.The various components type of the plastic compound and their impacts on plastic packaging are analyzed. After plastic packaging, pressure sensor chip is bonded with base tightly and cracks and holes are not appeared. Watkins fracture and leakage of glue phenomenon are also not appeared. The performances of pressure sensor with plastic packaging are as follows: resistance to hydrostatic of 3.5MPa with pressure time for 180 days, resistance to impact pressure of 1.6MPa with pressure cycles for 100,000 times, the maximum zero temperature coefficient of +0.08%FS/℃, the maximum linearity of +0.45%FS, operating temperature range of﹣20~+80℃, storage temperature range of﹣55~+150℃.The influences of thickness, depth and number of corrugation of corrugated diaphragm, soft glue and hard glue to pressure sensor are researched by finite element method, material object test and comparative validation in metal isolated packaging. Isolated outer casing and cavity structure, ceramic base structure, silicone oil to be handled and temperature compensation are also researched. After metal isolated packaging, the performances of pressure sensor for measuring medium adapting to 316 L stainless steel are as follows: the maximum zero output of +2mV, the maximum zero temperature deviation of ±1%FS, the maximum linearity of +0.25%FS, full scale temperature deviation of ±1%FS, operating temperature range of﹣40~+125℃, storage temperature range of﹣50~+125℃, pressure cycles for 1×108 times.