In-line process monitoring of advanced packaging process using Focused Beam Ellipsometry

[Display omitted] •Fully automated laser-based ellipsometry for on product wafer measurements.•Complete process characterization of advanced packaging applications.•Superior fleet matching on multi-layer stacks using feed forward metrology.•Accurate, high throughput measurements. The growing need for smaller, faster devices that consume less power at low cost has led to advances in wafer level packaging. The increasingly complex process employed at OSATs has generated a need for more advanced and automated measurement techniques. In this paper, we present results from the adoption of Focused Beam Ellipsometry in the characterization of thickness and optical constants of various single and multi-layer dielectrics films, thick photoresists on both blanket and product wafers. Measurements are routinely made post-deposition, post-etch and pre- and post CMP process. Wafer stress/wafer bow measurements provide information on the mechanical integrity of the films. The rapid non-contact, non-destructive technology enables full wafer characterization and provides information in minutes on product wafers.