Method and apparatus for measuring alignment of layers in photolithographic processes
US7349105B2 · kind B2 · utility
15Cited by
4References
18Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 1, 2004 |
| Grant date | Mar 25, 2008 |
| Priority date | — |
| Expiry date | Nov 25, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70633
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
According to a first embodiment of the invention, a first and second reticle are used to form layers using a photolithographic process. The first and second reticles each include a grating positioned so that when the reticles are printed, the two gratings will at least partially overlap each other. The two gratings produce an interference pattern, which is used to measure overlay error.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.