Wafer attracting and fixing device
US4521995A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 20, 1981 |
| Grant date | Jun 11, 1985 |
| Priority date | — |
| Expiry date | May 20, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/6838
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A work head for attracting and fixing an IC silicon wafer is comprised of an attracting disc and a base seat surrounding the periphery of the attracting disk. The attracting disc is of an inorganic substance shaped and sintered so that the upper layer of the attracting disc is composed of a porous body of porous grain and the lower layer the attracting body is formed with a slightly coarse body of porous grain. The base seat is made airtight, being formed and sintered with the same substance as the attracting disc. The attracting disc and the base seat are coupled with glass having a low melting point. The attracting disc is connected to a connecting hole drilled through the base seat and further to a water injecting hole and air sucking hole of a lower base. Before the wafer is attracted, water is injected from the injection hole for soaking the attracting surface. The surface tension of water transfers the wafer to the center of the attracting surface. Hereafter, the wafer is attracted onto the attracting surface by sucking air out. After the working, water is injected again for floating the wafer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.