US 12,394,655 B2
Subsurface alignment metrology system for packaging applications
Venkatakaushik Voleti, San Jose, CA (US); Keith Buckley Wells, Santa Cruz, CA (US); and Mehdi Vaez-Iravani, Los Gatos, CA (US)
Assigned to APPLIED MATERIALS, INC., Santa Clara, CA (US)
Filed by Applied Materials, Inc., Santa Clara, CA (US)
Filed on Nov. 23, 2022, as Appl. No. 17/993,096.
Prior Publication US 2024/0170317 A1, May 23, 2024
Int. Cl. H01L 21/68 (2006.01); H01L 23/00 (2006.01)
CPC H01L 21/681 (2013.01) [H01L 24/80 (2013.01); H01L 2224/8013 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An apparatus for detecting metrology data, comprising:
a source using a laser configured to illuminate a focal point through silicon, wherein the source uses only a single wavelength that is greater than 1100 nm and configured with sufficient light penetration into the silicon at a desired focal plane within the silicon to generate a diffraction-limited focus for subsurface imaging;
an optical lens configured to form an illumination beam when illuminated by the source;
an acousto-optic scanner configured to move the illumination beam back and forth in a scanning pattern;
a splitter configured to allow the illumination beam to be directed at a metrology sampling location while allowing a reflection beam caused by the illumination beam to pass through the splitter to a detector;
a set of optics configured to focus the illumination beam at a focal point in a Z direction to obtain subsurface images; and
a substrate platform configured to hold a substrate and to move the substrate in an X direction and a Y direction based on a metrology data acquisition pattern,
wherein the apparatus is configured to obtain metrology data for a semiconductor packaging process.