Ultra-thin full-frame high-temperature-resistant semiconductor strain gauge and preparation method therefor

A method for preparing an ultra-thin full-frame high-temperature resistant semiconductor strain gauge, specifically including the following steps:

• (1) taking a high-resistance silicon wafer with a thickness of 400-600 μm as a sacrificial layer, oxidizing the surface of the high-resistance silicon wafer, bonding another high-resistance silicon wafer onto the oxidized high-resistance silicon wafer, and thinning the upper high-resistance silicon wafer with a thinning machine to form a high-resistance silicon substrate layer;
• (2) growing a silicon dioxide oxide layer on the surface of the high-resistance silicon substrate layer, and growing a sub-nanocrystalline silicon thin film by low-pressure chemical vapor deposition (LPCVD);
• then performing photolithography for the heavy boron doping region and ion implantation with the photoresist mask in place;
• after heavy boron ion implantation, performing annealing and redistribution;
• subsequently performing photolithography for the resistance region and ion implantation with the photoresist mask in place;
• after light boron ion implantation, performing annealing and redistribution;
• (3) performing photolithography for the lead hole, depositing aluminum by evaporation, etching reversely, and alloying;
• then performing photolithography for the hole region and dry etching with the photoresist mask in place;
• performing deep ICP etching to a depth of 10 μm until self-termination, then removing the surface photoresist and depositing an insulating passivation layer;
• subsequently performing photolithography for the aluminum pressure feet and removing the surface photoresist;
• protecting the front side of the wafer, and etching away the sacrificial layer on the back side to form a semiconductor strain gauge with a thickness of 9-12 μm.