Chemical mechanical polishing system and method for optimization and control of film removal uniformity
US5653622A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1995 |
| Grant date | Aug 5, 1997 |
| Priority date | — |
| Expiry date | Jul 25, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB24B53/017
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A chemical mechanical polishing system for processing semiconductor wafers has a polishing arm and carrier assembly that press the topside surface of a semiconductor wafer against a motor driven, rotating polishing pad. Improved uniformity of material removal, as well as improved stability of material removal rate, is achieved through the use of a controller that applies a variable wafer backside pressure to the wafers being polished. More specifically, a control subsystem maintains a wafer count, corresponding to how many wafers have been polished by the polishing pad. The control subsystem regulates the backside pressure applied to each wafer in accordance with a predetermined function such that the backside pressure increases monotonically as the wafer count increases. In the preferred embodiment, the control system regulates the backside pressure in accordance with a linear function of the form: Backside Pressure=A+(B.times.Wafer Count). Whenever a new polishing pad is mounted, the wafer count value is reset to a predefined minimum wafer count value and the backside pressure for the next wafer to be polished is reset to a preset minimum backside pressure value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.