SUMMARY

Large area high throughput metrology plays an important role in several technologies like MEMS. In current metrology systems the parallel operation of multiple metrology probes in a tool has been hindered by their bulky sizes. This study approaches this problem by developing a metrology technique based on miniaturized scanning grating interferometers (μSGIs). Miniaturization of the interferometer is realized by novel micromachined tunable gratings fabricated using SOI substrates. These stress free flat grating show sufficient motion (~500nm), bandwidth (~50kHz) and low damping ratio (~0.05). Optical setups have been developed for testing the performance of μSGIs and preliminary results show a sub-picometer resolution. To achieve high resolution parallel operation and to reduce ambient noise the study has developed a novel control algorithm, implemented on FPGA. It has shown significant reduction of vibration noise (30-40dB in 400Hz bandwidth) and non-linearities. To analyze and simulate similar optical metrology system with active micro-components, separate tools are developed for mechanical, control and optical sub-systems; results show good agreement with experimental data. Remaining effort focuses on miniaturization of optical setup, extending the range of operation and demonstrating the parallel operation of μSGIs.