System and method for analyzing topological features on a surface
US6137570A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1998 |
| Grant date | Oct 24, 2000 |
| Priority date | — |
| Expiry date | Jun 30, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/95692
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed is a method and apparatus for using far field scattered and diffracted light to determine whether a collection of topological features on a surface (e.g., a semiconductor wafer) conforms to an expected condition or quality. This determination is made by comparing the far field diffraction pattern of a surface under consideration with a corresponding diffraction pattern (a "baseline"). If the baseline diffraction pattern and far field diffraction pattern varies by more than a prescribed amount or in characteristic ways, it is inferred that the surface features are defective. The method may be implemented as a die-to-die comparison of far field diffraction patterns of two dies on a semiconductor wafer. The portion of the far field scattered and diffracted light sensitive to a relevant condition or quality can also be reimaged to obtain an improved signal-to-noise ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.