Large area defect monitor tool for manufacture of clean surfaces
US5801824A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 25, 1996 |
| Grant date | Sep 1, 1998 |
| Priority date | — |
| Expiry date | Nov 25, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/9501
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and resulting system for directing generally collimated illumination from a source at an oblique angle to a surface under inspection (SUS) to produce scattered nonspecular energy substantially normal to the SUS and for observing the scattered nonspecular energy in one of a plurality of fractional windows of a viewed image of the SUS via a plurality of focussing elements. Such arrangement results in simultaneous and significant throughput and sensitivity enhancement over existing art. The method can be enhanced further wherein the observing step is performed through suitable relative motion of the scattering image over the imaging plane to permit over sampling. Furthermore, the DMT is significantly simplified because imaging is utilized to electronically scan the wafer instead of using opto-mechanical scanning means. Imaging sensors with an aggregate 2000.times.2000 pixel resolution could image a 200 mm wafer to 100 microns pitch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.