Analysis of thermal deformation patterns and accuracy impact in welding corrugated diaphragms of piezoresistive pressure sensors

Abstract High-precision diffused silicon piezoresistive pressure sensors are widely used in industrial automation, aerospace, and other fields. During their metal encapsulation process, corrugated diaphragms are often connected to the core using laser welding technology. However, it remains unclear how the deformation of the corrugated diaphragm, induced by thermal stresses during this process, impacts sensor accuracy. Therefore, this paper investigates the evolution patterns of corrugated diaphragm morphology induced by laser welding thermal effects and quantitatively evaluates the mechanism by which this evolution affects sensor accuracy. First, we established and validated a coupled thermal-deformation finite element simulation model against actual morphology measurements. Second, based on elastic mechanics theory, the relationship between corrugated diaphragm deformation and sensor output error was derived. Finally, the ‘welding thermal effect-corrugated diaphragm deformation-sensor accuracy’ mechanism was established, enabling analysis of the sensor’s full-scale error, sensitivity offset, and hysteresis error. Results indicate that welding thermal effects cause diaphragm deformation (average corrugation height difference