On-axix mask and wafer alignment system
US5966216A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 14, 1997 |
| Grant date | Oct 12, 1999 |
| Priority date | — |
| Expiry date | Feb 14, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/70
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An on-axis through the lens optical alignment system for use in semiconductor manufacturing using step and scan photolithographic techniques. An optical alignment system uses a partially common path with the projection optics (16) optical axis (38) in order to detect alignment targets on a wafer (10) and a mask (20). The relative position of the mask (20) and wafer (10) is detected during a single simultaneous scan, and the mask (20) and wafer (10) are resultantly aligned. This provides advantages over prior art multiple channel off-axis through the lens alignment systems and single channel non-through the lens alignment systems. A detailed optical apparatus (60) is disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.