Method and system for reducing the impact of across-wafer variations on critical dimension measurements
US7588868B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 2004 |
| Grant date | Sep 15, 2009 |
| Priority date | — |
| Expiry date | Sep 26, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70641
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
First and second exposures of a mask onto a wafer are performed such that the exposure field of the second exposure partially overlaps the exposure field of the first exposure. A characteristic of a set of features is determined, and a value of a parameter of an optical proximity correction model is determined. An alignment feature can be used to align a measurement tool. In yet another embodiment, pupil intensity distribution of an imaging system is measured by exposing an image field of a radiation detector with a bright feature, positioning the detector at a distance away from the image plane, and exposing the image field of the detector with a bright feature, resulting in a cumulative exposure of the image field of the detector from the two exposures. A characteristic of a spatial pattern in the cumulative exposure of the image field of the detector is then determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.