Die Attach Strength Study On MEMS Pressure Sensor

Pressure sensor is one kind of important sensor of IoT (Internet of Things). It iswidely used in automotive, medical, industry and consumer industries. MEMSpiezoresistive pressure sensor is widely used in different kind of application comparingother types’ pressure sensor since its low cost, high sensitivity, good linearity and smallsize.Manufacturing process of MEMS piezoresistive pressure sensor is complex. Dieattach is one of the key processes. It decides stability, accuracy and reliability ofproduct. It requires adequate die attach strength, sealing performance.To address low die shear force problem, study test method of die shear test method,properties of adherends (gold plated surface and fluorosilicone adhesive), relevantprocess and its flow (plasma clean, cure, baking, aging and etc.) then figure outautomation die shear test method to get more reasonable data, confirm plasma cleanduration time, optimize cure condition and process flow (remove baking, replaced withaging process, and move aging process from "after oil fill" to "before oil fill". Thegained advantage is that reduce cost and improve efficiency with guaranteed quality.Mechanism of die shear strength promotion is discussed based on some lab analysis,such as TOF-SIMS DMA, XPS and. Gold surface attains relative clean surface andhigher surface energy after plasma clean, so it can be easier wetted by adhesive and thisis one important factor for good adhesion. Baking can improve modulus of elasticity. Itcontributes die shear strength promotion for this cohesive die shear fracture mode.