SIL(Solid Immersion Lens) is well investigated for optical pickup application because of its capability of high resolution. We applied this technique to microscopy, especially for precise observation of semiconductors. And also we applied it to fault isolation techniques like emission microscopy , OBIRCH(Optical Beam Induced Resistance Change) and TIVA,SEI. We found significant enhancement of resolution and sensitvity by using SIL. Applying this technique to emission microscopy, we should be aware of optical absorption charactristics of SIL lens materials. We investigated proper SIL lens materials for emission microscopy and laser scanning applications, and checked performance of Si(Silicon)-SIL and GaP(Gallium phosphide)-SIL. We also compared combinations of some kinds of SILs and detectors like C-CCD(cooled CCD) camera, MCT(HgCdTe) camera and position sensitive detector with InGaAs photo cathode II(image intensifier).