Automated direct patterned wafer inspection
US5513275A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 9, 1994 |
| Grant date | Apr 30, 1996 |
| Priority date | — |
| Expiry date | Jun 9, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30148
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Disclosed is a new self-reference signal processing technique for detecting the location of any nonregularities and defects in a periodic two-dimensional signal or image. Using high-resolution spectral estimation algorithms, the proposed technique first extracts the period and structure of repeated patterns from the image to sub-pixel resolution in both directions, and then produces a defect-free reference image for making comparison with the actual image. Since the technique acquires all its needed information from a single image, on the contrary to the existing methods, there is no need for a database image, a scaling procedure, or any apriori knowledge about the repetition period of the patterns.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.