| With the development of MEMS, the surface profile has become one of the important factors of MEMS fabrication, simulation, quality evaluation and control. In general, MEMS devices are mm size in overall and um size in local. Thus, the testing technical is required to have high spatial resolution and large field of view.This paper set up a measurement system of the surface profile of microstructures based on image mosaic and phase-stepping microscopic interferometry. In experiments, the new system succeed to meet the requirement of high spatial resolution and large view. The major works in paper are following:1. This paper searched and compared appropriate matching algorithms in either time domain or frequency domain, such as matching criteria, improved matching criteria, digital image algorithm, and correlative function.2. The errors of single measurements, as well as those introduced by the stitching process were considered. In order to eliminate the out of plan warp, a compensation method was advanced: the initial amendment was carried through the unity of the sub-region coordinates, and then amending the gray of adjacent images one by one.3. Setting up a large view measurement system of the surface profile of microstructures based on the section of original phase-stepping microscopic interferometry and added in a section of scanning location. The section of scanning location was including stepping motor, driver, SCM, elevating platform, etc.4. Testing and measurement experiments. There was a single measurement experiment using triangle step-height standard and a compared experiment that curved surface was measured by using different view microscopic, to validate the system's measuring precision and feasibility. Besides, the proportion of the overlaps in the matched images could also affect the measurement greatly, and comparison experiments were taken to analytics. Then the surface profile of different microstructures was matched by using different matching methods. |
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