To meet the demand for the efficient preparation of the suspended structure of medical uncooled thermal infrared detectors, this paper proposes a front-opening rapid wet etching process based on <100>-oriented silicon wafers. Three types of <100>-oriented slit-shaped opening structures, namely the zigzag type, the strip type, and the composite type, are designed. Combined with the SiO2/Si3N4 stress-compensated composite film, after 120 minutes of anisotropic etching in a KOH solution with a molar concentration of 30% at a water bath temperature of 80 ℃, the high-precision release of the suspended structure is achieved. The experimental results show that the composite opening significantly improves the penetration efficiency of the etching solution by adding auxiliary openings in the cantilever beam area. Compared with the back-side sacrificial layer etching method, the etching time is shortened by 60%. The effect is far better than that of the front-side sacrificial layer etching, with the release area reaching over 98% and the yield rate increased to 95%. On this basis, by adopting a single-side processing flow that is fully compatible with the CMOS process, P/N polysilicon thermopiles and amorphous silicon microbolometer units are successfully fabricated. In the detection of ear temperature/forehead temperature, a temperature measurement accuracy of ±0.1 ℃ and a response time of less than 500 milliseconds are achieved, meeting the requirements of medical-grade equipment for high precision and rapid response. The integrated process flow of “crystal orientation design-stress regulation-etching optimization” proposed in this study provides a reliable solution for the batch preparation of high-performance suspended structures and has important application value in the field of wearable health monitoring devices.