Method and apparatus for determining endpoint during a polishing process
US5830041A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1996 |
| Grant date | Nov 3, 1998 |
| Priority date | — |
| Expiry date | Nov 4, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB24B49/16
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method and apparatus for determining a planar end point on a workpiece such as a semiconductor wafer in a polishing process for polishing the workpiece to a flat mirror finish. The workpiece having an uneven surface is held by a top ring and pressed against a polishing platen. The workpiece is moved relative to the polishing platen to polish the workpiece, and a change in a frictional force between the workpiece and the polishing platen is detected. A reference time when the workpiece having an uneven surface is polished to a flat surface is determined based on the change of the frictional force between the workpiece and the polishing platen. The time when a certain period of polishing time from the reference time elapses is determined as an endpoint on the workpiece.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.