Nano-level 3-D shape extraction of precise parts using combination of multiple wave-length lasers

To improve the productivity of very large scale of LSIs or large LCD panels, not only the technologies to inspect the LSIs or the LCDs but to repair them are required. To remove the less than one-micrometer contaminants on the LSIs, it is required to extract their 3-D shape, precisely. To meet with these requirements, a nano-level 3-D shape extraction method has been developed. Here, the basic idea of the method and the simulation result are described. To extract a nano-level 3-D shape, the method using some interference images is effective. Interference image is produced by light reflected by LSI and light, which is not reflected by LSI. At this time, if the light, which is not reflected by LSI, is changed at regular intervals, the brightness of same coordinate of interference images change like a sine wave. When each heights of LSI differ between coordinates, the brightness of interference image differs. And the phases of brightness pattern differ according to height between each pixel. To measure heights from these phases, the pattern matching method was used and compared it with template images. The algorithm and system to process at the same times it taken in interference images is described. Also, to meet with the requirement to measure more than wave-length, the combination method of multiple wavelength lasers has been introduced. It enables to measure 100 um height differences with nano-level accuracy