Part locating, mask alignment and mask alignment verification system
US3989385A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1974 |
| Grant date | Nov 2, 1976 |
| Priority date | — |
| Expiry date | Sep 16, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/70
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and apparatus for locating target patterns with reference to a fixed axis. The apparatus includes a collimated light source providing a light beam to a rotating prism and optical flat producing a rotating light beam. A lens whose axis is the fixed axis focuses the beam to a spot on a surface containing a pattern comprising regularly spaced light scattering surfaces. A light sensor detects light from the rotating beam scattered by the target. An incremental shaft encoder provides a real time indication of spot position. The light sensor output provides a measure of target location and orientation with reference to the lens axis. The encoder can be used to control sampling apparatus and an A/D converter to provide regular digital samples of the light sensor output. The method includes providing a target with regularly spaced light scattering areas, rotating a light beam about an axis, detecting the scattered light and determining from the relative radial spot position at the time scattered light is detected the relationship between the beam axis and the target axis and orientation. The basic apparatus and method referred to above is useful in the manufacture of integrated ci…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.