Spectral reflectometry sensor for a feedback loop in the polishing of material samples

Abstract

A machine and method for measuring surface roughness of a material during polishing for material characterization. The machine comprises a stage for supporting the material, a laser diode generating a laser beam directed toward the stage, a beamshaper for shaping the laser beam, a beamsplitter for splitting the beam into portions with one portion directed toward the material, a photodetector for measuring intensity of reflective light from the material surface, and a control system programmed to create maps of surface roughness based on measured reflective light intensity at different positions. The method comprises polishing with successive grits, measuring surface roughness using reflective light to create maps after each polishing step, and comparing the maps to determine changes in reflected light. The feedback loop automates polishing without predetermined recipes and enables error detection during the polishing process.

Dependencies are inferred from the claim text.