Semiconductor wafer surface inspection apparatus and method
US4740708A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 6, 1987 |
| Grant date | Apr 26, 1988 |
| Priority date | — |
| Expiry date | Jan 6, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/0655
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system and procedure for the inspection of the surface of a semiconductor wafer ascertains that particulate contaminants have been adequately cleaned from the surface during the manufacture of integrated electric circuits. The wafer is advanced in a first direction and is optically scanned in a second direction, transverse to the first direction, for recording intensities of light reflected normally from the wafer surface as a function of location on the scan line. A high intensity reflection is indicative of a smooth flat surface suitable for inspection of particles by an integrating hemisphere with plural photodetectors therein. A weak reflection is indicative of undulations and patterned regions which are unfavorable for examination of particles on the wafer surface. A second scan is offset sideways to compensate for motion of the wafer so as to rescan the same line as the first scan. The photodetectors in the integrating sphere are gated on and off during the second scan at the locations of suitable inspection sites determined from the first scan.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.