Device and method for positioning a notched wafer
US5851102A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1997 |
| Grant date | Dec 22, 1998 |
| Priority date | — |
| Expiry date | Sep 16, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S414/136
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A detector is provided to optically monitor the outer periphery of a wafer rotated by rotation of a rotary stage, so as to detect how much the center of the wafer placed on the rotary inspection stage is offset from the rotational center of the rotary stage as well as an angular position, on the stage, of a V-shaped notch formed in the wafer. From the detected eccentricity of the wafer, it is determined whether a precise positioning operation, using at least three positioning pins, to locate the center of the wafer at the rotational center of the rotary stage should be performed or not. When the detected eccentricity is so great as to necessitate the precise positioning operation, one of the positioning pins is caused to fit into the V-shaped notch of the wafer on the basis of the detected angular position of the notch and then the precise positioning of the wafer is performed using the other two positioning pins. In this manner, the wafer can be properly positioned so that the center of the wafer lies exactly at the rotational center of the rotary stage, using the at least three positioning pins.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.