Semiconductor wafer cassette mapper with emitter and detector arrays for slot interrogation
US5225691A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 1992 |
| Grant date | Jul 6, 1993 |
| Priority date | — |
| Expiry date | May 18, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S414/137
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A semiconductor wafer cassette mapper detects the presence absence of a semiconductor wafer in a particular corresponding pair of slots of the wafer cassette, as well as a cross slotted condition in which a wafer is not aligned in a corresponding pair of slots. The wafer cassette mapper includes a base member for receiving a standard slotted wafer cassette, the base member including transmitter and receiver modules on opposite sides thereof. The transmitter and receiver modules include like pluralities of inwardly facing, aligned light apertures. Each of the light apertures in the transmitter module contains a light emitting infrared transmitter, and each of the light apertures in the receiver module contains an infrared receiver. Control circuitry selectively activates the light emitting transmitters for a predetermined period of time and selectively interrogates the infrared receivers during that period of time to determine if a particular receiver has received light transmitted by a selected transmitter. Logic circuitry then processes this information to determine if a particular wafer position is empty and if a cross slotted condition exists.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.