“A research on high-precision non-contact measurement of semiconductor wafer thickness has made significant progress. This study proposes a wafer thickness measurement method based on laser confocal technology, which achieves high-precision aiming and positioning of the upper and lower surfaces of the wafer, and accurately calculates the physical coordinates of each sampling point through ray tracing algorithm. The experimental results show that the axial resolution of this method is better than 5nm, the scanning range can reach 5.7mm, and the measurement repeatability is good, with a single measurement time of less than 400ms. This study not only provides a new technology for high-precision and non-destructive online measurement of semiconductor wafer thickness, but also offers new ideas for research and applications in related fields.”