Optical design of laser scanning interferometer confocal microscope system

As semiconductor devices, optical components and micromechanical devices are increasingly miniaturized, the demand for the detection of their three-dimensional microstructures, scratch defects, etc. is growing. To this end, an interferometric confocal laser microscopy system with high resolution and fast scanning speed is designed. The composition and working principle of the laser confocal interferometric microscope are briefly introduced, and the optimization design method and results of the optical system are given in detail. The imaging quality is analyzed and evaluated based on the point diagram and modulation transfer function of the system. The results show that the designed confocal microscope lens has a lateral resolution of 625 nm and an axial resolution of 4.24 μm. The interferometric confocal microscopy system has both high resolution and high precision detection capabilities, and can detect defects with a minimum depth of 10 nm.