Patent US5653622A successfully refreshed from Google Patents.
US5653622A
Expired / Lapsed
US
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Chemical mechanical polishing system and method for optimization and control of film removal uniformity
Assignee: Philips Semiconductors Inc
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Filing: 1995-07-25
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Granted: 1997-08-05
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Expires: 2015-07-25
Abstract
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×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.
Inventors
- 👤 Charles Drill
- 👤 Milind G. Weling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:41
CPC Classifications
B; B24; B24B; B24B37/00; B24B37/04; B24B37/07; B24B37/10; B24B37/105; B24B37/107; B24B49/00; B24B49/16; B24B53/00; B24B53/017
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
118 words
A chemical mechanical polishing (CMP) system, comprising: a motor driven polishing pad; a wafer carrier for holding a semiconductor wafer against the polishing pad such that a topside surface of the wafer is polished by said polishing pad; a pressure subsystem, coupled to the wafer carrier, for applying a controllable amount of pressure to a backside of the wafer held by the wafer carrier; and a control subsystem coupled to said pressure subsystem for maintaining a wafer count, corresponding to how many wafers have been polished by said polishing pad, and for regulating said backside pressure applied to said wafer in accordance with a predetermined function such that said backside pressure increases monotonically as said wafer count increases.
Claim 2
Dependent Claim
118 words
A chemical mechanical polishing (CMP) system, comprising: a motor driven polishing pad; a wafer carrier for holding a semiconductor wafer against the polishing pad such that a topside surface of the wafer is polished by said polishing pad; a pressure subsystem, coupled to the wafer carrier, for applying a controllable amount of pressure to a backside of the wafer held by the wafer carrier; and a control subsystem coupled to said pressure subsystem for maintaining a wafer count, corresponding to how many wafers have been polished by said polishing pad, and for regulating said backside pressure applied to said wafer in accordance with a predetermined function such that said backside pressure increases monotonically as said wafer count increases.
Claim 3
Dependent Claim
26 words
The CMP system of claim 1, wherein said control system regulates said backside pressure in accordance with a linear function of the form: Backside pressure=A+(B×Wafer Count).
Claim 4
Dependent Claim
47 words
The CMP system of claim 2, wherein whenever a new polishing pad is mounted, said control system resets said wafer count to a predefined minimum wafer count value and resets the backside pressure for the next wafer to be polished to a preset minimum backside pressure value.
Claim 5
Dependent Claim
47 words
The CMP system of claim 1, wherein whenever a new polishing pad is mounted, said control system, resets said wafer count to a predefined minimum wafer count value and resets the backside pressure for the next wafer to be polished to a preset minimum backside pressure value.
Claim 6
Independent Claim
91 words
A method of chemical mechanical polishing semiconductor wafers, comprising the steps of: holding a semiconductor wafer against a motor driven polishing pad such that a topside surface of the wafer is polished by said polishing pad; applying a controllable amount of pressure to a backside of the wafer; maintaining a wafer count, corresponding to how many wafers have been polished by said polishing pad; and regulating said backside pressure applied to said wafer in accordance with a predetermined function such that said backside pressure increases monotonically as said wafer count increases.
Claim 7
Independent Claim
91 words
A method of chemical mechanical polishing semiconductor wafers, comprising the steps of: holding a semiconductor wafer against a motor driven polishing pad such that a topside surface of the wafer is polished by said polishing pad; applying a controllable amount of pressure to a backside of the wafer; maintaining a wafer count, corresponding to how many wafers have been polished by said polishing pad; and regulating said backside pressure applied to said wafer in accordance with a predetermined function such that said backside pressure increases monotonically as said wafer count increases.
Claim 8
Dependent Claim
25 words
The method of claim 5, wherein said regulating step regulates said backside pressure in accordance with a linear function of the form: Backside pressure=A+(B×Wafer Count).
Claim 9
Dependent Claim
44 words
The method of claim 6, wherein whenever a new polishing pad is mounted, said wafer count is reset to a predefined minimum wafer count value and resets the backside pressure for the next wafer to be polished to a preset minimum backside pressure value.
Claim 10
Dependent Claim
44 words
The method of claim 5, wherein whenever a new polishing pad is mounted, said wafer count is reset to a predefined minimum wafer count value and resets the backside pressure for the next wafer to be polished to a preset minimum backside pressure value.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-08-04 | 2001-02-03 | 2001-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-04 | 2005-02-03 | 2005-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-04 | 2009-02-03 | 2009-08-05 | $7700.00 | Window Closed / Lapsed |