US6007405A
Expired / Lapsed
US
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Method and apparatus for endpoint detection for chemical mechanical polishing using electrical lapping
Assignee: Siemens AG
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Filing: 1998-07-17
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Granted: 1999-12-28
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Expires: 2018-07-17
Abstract
Abstract A chemical mechanical polisher for polishing a surface of a semiconductor wafer is disclosed. The polisher comprises: a polishing table for holding a polishing pad; a rotatable wafer chuck for holding said semiconductor wafer against said polishing pad; an electrical lapping guide secured to said wafer chuck, said electrical lapping guide comprising: a polishable resistive sensor that has a variable resistance dependent upon the amount of material removed from said resistive sensor during polishing; and a bias means for applying a bias to said resistive sensor such that said resistive sensor is in contact with said polishing pad during polishing; a resistance sensing means for determining said variable resistance of said resistive sensor; and a microprocessor for determining the amount of material polished from said resistive sensor based upon said variable resistance.
Inventors
- 👤 Len Mei
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 08:32
CPC Classifications
B; B24; B24B; B24B37/00; B24B37/005; B24B37/013; B24B49/00; B24B49/02; B24B49/04; B24B49/10
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
114 words
A chemical mechanical polisher for polishing a surface of a semiconductor wafer, the chemical mechanical polisher comprising: a polishing table for holding a polishing pad; a rotatable wafer chuck for holding said semiconductor wafer against said polishing pad; an electrical lapping guide secured to said wafer chuck, said electrical lapping guide comprising: a polishable resistive sensor that has a variable resistance dependent upon the amount of material removed from said resistive sensor during polishing; and a bias means for applying a bias to said resistive sensor such that said resistive sensor is in contact with said polishing pad during polishing; and a resistance sensing means for determining said variable resistance of said resistive sensor.
Claim 2
Dependent Claim
114 words
A chemical mechanical polisher for polishing a surface of a semiconductor wafer, the chemical mechanical polisher comprising: a polishing table for holding a polishing pad; a rotatable wafer chuck for holding said semiconductor wafer against said polishing pad; an electrical lapping guide secured to said wafer chuck, said electrical lapping guide comprising: a polishable resistive sensor that has a variable resistance dependent upon the amount of material removed from said resistive sensor during polishing; and a bias means for applying a bias to said resistive sensor such that said resistive sensor is in contact with said polishing pad during polishing; and a resistance sensing means for determining said variable resistance of said resistive sensor.
Claim 3
Dependent Claim
25 words
The apparatus of claim 1, further including a microprocessor for determining the amount of material polished from said resistive sensor based upon said variable resistance.
Claim 4
Dependent Claim
44 words
The apparatus of claim 1, wherein said resistance sensing means comprises: a voltage source for applying a voltage to said resistive sensor; a current detector for detecting a current flow rate that is indicative of the amount of current flowing through said resistive sensor.
Claim 5
Dependent Claim
39 words
The apparatus of claim 1, wherein said resistance sensing means comprises: a current source for applying a current to said resistive sensor; a voltage detector for detecting a voltage that is indicative of the voltage across said resistive sensor.
Claim 6
Dependent Claim
18 words
The apparatus of claim 1 wherein a plurality of electrical lapping guides are attached to said wafer chuck.
Claim 7
Dependent Claim
12 words
The apparatus of claim 1 wherein said bias means is a spring.
Claim 8
Dependent Claim
20 words
The apparatus of claim 1 wherein said bias means is operative to provide an adjustable bias to said resistive sensor.
Claim 9
Dependent Claim
17 words
The apparatus of claim 1 wherein said resistive sensor is an array of resistors connected in parallel.
Claim 10
Dependent Claim
20 words
The apparatus of claim 8 wherein said array of resistors are formed from thin film polysilicon on a semiconductor substrate.
Claim 11
Dependent Claim
54 words
The apparatus of claim 1 wherein said resistive sensor includes at least two arrays of resistors, each array of resistors connected in parallel and formed from alternating blank portions and resistor elements, said at least two arrays of resistors connected in series and having their blank portions and resistor elements offset from each other.
Claim 12
Independent Claim
138 words
A method of determining the amount of material removed from a semiconductor wafer during a polishing by a chemical mechanical polisher, said polisher including a polishing table for holding a polishing pad and a rotatable wafer chuck for holding said semiconductor wafer against said polishing pad, the method comprising the steps of: securing an electrical lapping guide to said wafer chuck, said electrical lapping guide comprising: a polishable resistive sensor that has a variable resistance dependent upon the amount of material removed from said resistive sensor during polishing; and a bias means for applying a bias to said resistive sensor such that said resistive sensor is in contact with said polishing pad during polishing; determining said variable resistance of said resistive sensor; and determining the amount of material polished from said resistive sensor based upon said variable resistance.
Claim 13
Independent Claim
138 words
A method of determining the amount of material removed from a semiconductor wafer during a polishing by a chemical mechanical polisher, said polisher including a polishing table for holding a polishing pad and a rotatable wafer chuck for holding said semiconductor wafer against said polishing pad, the method comprising the steps of: securing an electrical lapping guide to said wafer chuck, said electrical lapping guide comprising: a polishable resistive sensor that has a variable resistance dependent upon the amount of material removed from said resistive sensor during polishing; and a bias means for applying a bias to said resistive sensor such that said resistive sensor is in contact with said polishing pad during polishing; determining said variable resistance of said resistive sensor; and determining the amount of material polished from said resistive sensor based upon said variable resistance.
Claim 14
Dependent Claim
27 words
The method of claim 11 further including the step of stopping said polishing when the amount of material polished from said resistive sensor reaches a predetermined threshold.
Claim 15
Dependent Claim
53 words
The method of claim 11 wherein said step of determining said variable resistance comprises: applying a voltage to said resistive sensor; detecting a current flow rate that is indicative of the amount of current flowing through said resistive sensor; and determining said variable resistance as said voltage divided by said current flow rate.
Claim 16
Dependent Claim
46 words
The method of claim 11, wherein said step of determining said variable resistance comprises: applying a current to said resistive sensor; detecting a voltage that is indicative of the voltage across said resistive sensor; and determining said variable resistance as said voltage divided by said current.
Claim 17
Dependent Claim
134 words
A chemical mechanical polisher for polishing a surface of a semiconductor wafer, the chemical mechanical polisher comprising: a polishing table for holding a polishing pad; a rotatable wafer chuck for holding said semiconductor wafer against said polishing pad; an electrical lapping guide secured to said wafer chuck, said electrical lapping guide comprising: a polishable resistive sensor that has a variable resistance dependent upon the amount of material removed from said resistive sensor during polishing; and a bias means for applying a bias to said resistive sensor such that said resistive sensor is in contact with said polishing pad during polishing; a voltage source for applying a voltage to said resistive sensor; and a current detector for detecting a current flow rate that is indicative of the amount of current flowing through said resistive sensor.
Claim 18
Dependent Claim
134 words
A chemical mechanical polisher for polishing a surface of a semiconductor wafer, the chemical mechanical polisher comprising: a polishing table for holding a polishing pad; a rotatable wafer chuck for holding said semiconductor wafer against said polishing pad; an electrical lapping guide secured to said wafer chuck, said electrical lapping guide comprising: a polishable resistive sensor that has a variable resistance dependent upon the amount of material removed from said resistive sensor during polishing; and a bias means for applying a bias to said resistive sensor such that said resistive sensor is in contact with said polishing pad during polishing; a voltage source for applying a voltage to said resistive sensor; and a current detector for detecting a current flow rate that is indicative of the amount of current flowing through said resistive sensor.
Claim 19
Dependent Claim
26 words
The apparatus of claim 15 further including a microprocessor for determining the amount of material polished from said resistive sensor based upon said current flow rate.
Claim 20
Dependent Claim
18 words
The apparatus of claim 15 wherein a plurality of electrical lapping guides are attached to said wafer chuck.
Claim 21
Dependent Claim
12 words
The apparatus of claim 15 wherein said bias means is a spring.
Claim 22
Dependent Claim
20 words
The apparatus of claim 15 wherein said bias means is operative to provide an adjustable bias to said resistive sensor.
Claim 23
Dependent Claim
17 words
The apparatus of claim 15 wherein said resistive sensor is an array of resistors connected in parallel.
Claim 24
Dependent Claim
54 words
The apparatus of claim 15 wherein said resistive sensor includes at least two arrays of resistors, each array of resistors connected in parallel and formed from alternating blank portions and resistor elements, said at least two arrays of resistors connected in series and having their blank portions and resistor elements offset from each other.
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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) | 2002-12-27 | 2003-06-28 | 2003-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-12-27 | 2007-06-28 | 2007-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-12-27 | 2011-06-28 | 2011-12-28 | $7700.00 | Window Closed / Lapsed |