Method and apparatus for measurement and control of photomask to substrate alignment
US7935546B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 6, 2008 |
| Grant date | May 3, 2011 |
| Priority date | — |
| Expiry date | Sep 25, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7076
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method, structure, system of aligning a substrate to a photomask. The method includes: directing incident light through a pattern of clear regions transparent to the incident light in an opaque-to-the-incident-light region of a photomask, through a lens and onto a photodiode formed in a substrate, the photodiodes electrically connected to a light emitting diode formed in the substrate, the light emitting diode emitting light of different wavelength than a wavelength of the incident lights; measuring an intensity of emitted light from light emitting diode; and adjusting alignment of the photomask to the substrate based on the measured intensity of emitted light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.