Process for positioning a mask relative to a workpiece and device for performing the process
US5777747A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 29, 1995 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Nov 29, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/70
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A process and apparatus for positioning a mask relative to a workpiece in which the relative positions of the alignment marks of the alignment mark of the mask and the workpiece can be easily recognized are achieved according to the invention by the fact that alignment light is emitted onto the mask alignment marks, projected images of the alignment marks of the mask are recorded by alignment units and undergo image processing, the relative positions are determined and stored, then emission of alignment light is stopped, alignment light is then emitted onto the alignment marks of the workpiece from the partial illumination systems, the alignment marks of the workpiece are recorded and undergo image processing, the relative positions thereof are determined and stored, data of the relative positions of the alignment marks of the mask and workpiece are computed, and relative movement of the workpiece and the mask is produced to position the two alignment marks one on top of the other.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.