Full-field microsurface profilometry using image correlation without vertical scanning
Journal
Optics Letters
Journal Volume
44
Journal Issue
14
Pages
3534-3537
Date Issued
2019
Author(s)
Abstract
A full-field microprofilometry involving innovative image correlation was developed for profile measurement without vertical scanning. High-speed optical inspection has become critical for confirming precise dimensions in semiconductor fabrication such as microbumping in 3D stacked ICs and precision manufacturing. A digital micromirror device (DMD) is designed to serve as a point-light-source array in a quasiconfocal optical configuration and perform lateral scanning to minimize signal crosstalk between neighboring testing points. More importantly, multiple diffractive images are detected and measured with a prebuilt depth-correlated database to extract the height information of a tested surface. A 100-nm repeatability can be realized in the absence of a detector pinhole and without vertical scanning, thus achieving high-speed submicrometer-scale surface profilometry.
Type
journal article