Grinding process and apparatus for planarizing sawed wafers
US5964646A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 17, 1997 |
| Grant date | Oct 12, 1999 |
| Priority date | — |
| Expiry date | Nov 17, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB24B41/06
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method and apparatus for planarizing silicon wafers initially having wavy surfaces, such as might result from having been cut from a boule by means of a wire saw. A vacuum is applied to one side of a porous ceramic plate, and a perforated resilient pad is applied to the opposite side of the porous ceramic plate. The resilient pad is affixed to the ceramic plate by a peelable adhesive, and the vacuum extends through the perforations of the resilient pad to permit a wafer to be mounted on the exposed side of the resilient pad. The perforations in the resilient pad are distributed uniformally across the wafer, so that the atmospheric pressure pushing the wafer against the resilient pad is also uniform across the wafer. However, the wafer is not deformed while it is held in place for grinding. Because the wafer is not held in an elastically deformed condition while it is ground, the wafer has no tendency to spring back to its original wavy shape. Once one side of the wafer has been planarized, conventional methods can be employed to planarize the second surface of the wafer and to make uniform its thickness. The method is fully compatible with existing grinding machines and, except f…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.