Toward extreme throughput nanotopography metrology with atomic force microscope arrays

Achieving angstrom-level precision measurement in the Z axis has become critical for semiconductor process control in applications such as hybrid bonding copper pad recess. The only technique that can achieve ground truth measurements in the Z axis with sufficient lateral resolution is atomic force microscopy (AFM). We present an AFM technology based on micro-electro-mechanical systems (MEMS) that is exceptionally scalable due to the small footprint (1 mm2) of each scan head. In this work, we present a system with an array of 10 scan heads where all scan heads can navigate, approach and scan 10 sites simultaneously across a 300-mm wafer radius. As a demonstration, the same target on 10 adjacent dies of hybrid bonding copper pads was scanned and analyzed. We show a path towards throughput of hundreds of thousands of dies per hour with AFM and discuss the possibility for throughput that would enable inspection with AFM.