Nano-level 3-D measurement system using combination of 3-wavelength laser lights

To improve the productivity of very large scale of TSIs or large LCD panels, the nano-technologies to inspect the TSIs are required. To remove the less than one-micrometer contaminants on the TSIs, it is required to extract their positions and 3-D shapes, precisely. To meet with these requirements, a nano-level 3-D shape extraction method has been introduced and the measurement results are described. Here, the basic idea of this method and the measurement result using improvement method are described. To extract a nano-level 3-D shape, the method using laser interference images is effective. Interference image is produced by light reflected by TSI and by reference mirror. At this time, if the position of reference light is changed at regular intervals, the brightness of same coordinate of interference images change like a sine wave. When position heights of TSI differ between two coordinates, the brightness of interference image differs and the phases of brightness pattern differ according to height between each pixel. And combining with different wavelength laser lights, different brightness is able to measure more than one wavelength. Took-up table method is used to combine the multi-wavelength laser light measurement.