Lithographic projection apparatus with an alignment system for aligning substrate on mask
US6297876A · kind A · utility
93Cited by
14References
35Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 6, 1998 |
| Grant date | Oct 2, 2001 |
| Priority date | — |
| Expiry date | Mar 6, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/70
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A lithographic projection apparatus with an off-axis alignment unit for aligning a substrate alignment mark (P1) with respect to a reference (RGP) is described. This unit comprises a structure (WEP) of deflection elements (80-86) which give the sub-beams having different diffraction orders coming from the diffractive substrate mark (P1) different directions so that these sub-beams are incident on separate reference gratings (90-96) and can be detected by separate detectors (DET). This unit also provides the possibility of aligning asymmetrical alignment marks with great accuracy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.