Machine-independent alignment system and method
US6898306B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 14, 2001 |
| Grant date | May 24, 2005 |
| Priority date | — |
| Expiry date | Jan 27, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T7/30
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of measuring machine alignment offset of an optical machine having an alignment system, so that subsequent processing of substrates on set of optical machines can be performed in a machine-independent manner. The optical machine forms overlayed images of first and second patterns formed on either one or two reticles onto a substrate at respective first and second levels. The method of the invention includes forming a virtual zero-offset alignment pattern and a virtual zero-offset metrology pattern and imaging first and second metrology patterns on the substrate at the first and second levels, respectively. The second metrology pattern is aligned to the first metrology pattern using the zero-offset alignment pattern so that the exposures are performed in an overlayed manner. The first and second metrology patterns are based on the virtual zero-offset metrology pattern. An image of the overlayed first and second metrology patterns formed on the substrate is obtained using the alignment system of the optical machine. The virtual zero-offset metrology pattern is compared to corresponding portions of the image of the overlayed metrology patterns to deduce an offset from an idea…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.