Method and apparatus for aligning mask and wafer members
US4326805A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 11, 1980 |
| Grant date | Apr 27, 1982 |
| Priority date | — |
| Expiry date | Apr 11, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/703
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Zone plate patterns (12,20,61,62) formed on spaced-apart mask and wafer members (10,60) are utilized for alignment purposes in the fabrication of integrated circuits. By providing off-axis illumination of the patterns, a significant mask-to-wafer alignment capability is provided in an X-ray lithographic system. This capability includes being able to correct for so-called magnification errors that arise from physical distortions in the mask and/or wafer or in other components of the system. These errors are compensated for by utilizing the zone plate patterns to form alignment marks that serve as a basis for adjusting the mask-to-wafer separation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.