Parallel MEMS AFM for high-throughput semiconductor metrology and inspection

In this work, an AFM platform that could meet the throughput requirements for inline measurement is demonstrated by MEMS AFM devices capable of 3 degrees of freedom (XYZ) movement and is self-sensing. Each MEMS AFM device occupies a footprint of 1 mm² and is mass-manufactured using a scalable CMOS-MEMS process. Furthermore, these MEMS AFMs are low mass and overcome the fundamental speed limitations of traditional bulk piezoelectric scanners. Two relevant applications for semiconductor metrology and inspection are explored using MEMS AFM devices on IPneutral AMAG7 193i test structures. Two specific examples of applications of after etch inspection — line edge roughness metrology and rapid defect inspection — were demonstrated. An array of four simultaneously scanning parallel AFMs is also presented, and topography data collected from a nanoimprinted polymer is shown. The CMOS-MEMS manufacturing process enables the possibility of scaling AFMs to achieve simultaneous scanning of thousands of sites. The massive parallelization of AFMs enables true wafer map sampling and paves the path toward parts per billion defect control and massive metrology with high wafer coverage.