Verifying alignment of multiple die on a substrate

Abstract

A top-down inspection system and method employs a strategy using specific geometric shaped metal alignment markers on a semiconductor die and a laminate that can be inspected using an IR camera. The metal alignment markers will align at room temperature to assess the die alignment prior to reflowing it. As silicon is transparent to IR wavelengths the system allows for the IR light to pass through the die to the laminate to see alignment features on the die and the laminate concurrently. The specific markers are placed in at least two separate locations preferably >0.5*die size apart. The robust alignment markers are substantially resistant to degradation caused by semiconductor device fabrication steps. The metal alignment markers can be small geometrical shapes to provide a more symmetrical signal which is more resistant to variability in prior processing steps than the standard marker design.