System for achieving a parallel relationship between surfaces of wafer and reticle of half-field dyson stepper
US5329332A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1992 |
| Grant date | Jul 12, 1994 |
| Priority date | — |
| Expiry date | Dec 21, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/70
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is tilt-sensing means that employs a point source of alternate 1st or 2nd divergent light beams which, after passing through collimating lenses of the Half-Field Dyson projection optics of the stepper, are separately incident on and reflected from a reflective pattern disposed on the surface of a reticle and from a reflective surface of a wafer, together with two-dimensional position detection means responsive to the position of each of the reflected alternate 1st or 2nd divergent light beams, for independently sensing the angular position of the surface of the reticle and the angular position of the surface of the wafer to determine thereby whether or not the surface of the reticle and the surface of the wafer are substantially parallel to one another. This permits adjustment means of the stepper, which is responsive to the respective surfaces having been determined by the tilt-sensing means to be not parallel to one another, to angularly adjust the angular position of at least one of the reticle and the wafer to bring the respective surfaces thereof into a substantially parallel relationship with one another.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.