US5793192A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods and apparatuses for clamping and declamping a semiconductor wafer in a wafer processing system
Assignee: Lam Research Corp
•
Filing: 1996-06-28
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Granted: 1998-08-11
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Expires: 2016-06-28
Abstract
Abstract A method for clamping a wafer to an electrostatic chuck having a substantially resistive dielectric layer disposed thereon. The method includes the step of providing a build-up voltage having a first polarity to a pole of the electrostatic chuck to cause a potential difference to build up between a first region of the substantially resistive dielectric layer and a second region of the wafer that overlies at least a portion of the first region. This potential difference gives rise to a clamping force to clamp the wafer to the electrostatic chuck. The method further includes the step of terminating the build-up voltage when the clamping force substantially reaches a predefined level. There is further included the step of providing a holding voltage to the pole of the electrostatic chuck to substantially maintain the clamping force at the predefined level. This holding voltage has the first polarity and a magnitude that is lower than a magnitude of the build-up voltage. There is further included the step of providing a declamping voltage to the pole of the electrostatic chuck to substantially remove the clamping force, the declamping voltage having a polarity that is opposite to the first polarity.
Inventors
- 👤 Marc B. Kubly
- 👤 Neil Martin Paul Benjamin
- 👤 Steven Douglas Germain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:36
CPC Classifications
H; H02; H02N; H02N13/00; H10; H10P; H10P72/00; H10P72/70; H10P72/72; H10P72/722; Y; Y10; Y10T; Y10T279/00; Y10T279/23
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
218 words
A control system for controlling a direct current power supply, said direct current power supply supplying direct current voltages to a pole of an electrostatic chuck having a substantially resistive dielectric layer disposed thereon to clamp a wafer to said electrostatic chuck, comprising: a control circuit electrically coupled to said direct current power supply for causing said direct current power supply to output said direct current voltages at: a build-up voltage having a first polarity during a build-up period to cause a potential difference to build up between a first region of said substantially resistive dielectric layer and a second region of said wafer that overlies at least a portion of said first region, said potential difference giving rise to a clamping force to clamp said wafer to said electrostatic chuck, said build-up period terminating when said clamping force substantially reaches a predefined level; a holding voltage during a holding period to substantially maintain said clamping force at said predefined level, said holding voltage having said first polarity and a magnitude that is lower than a magnitude of said build-up voltage, said holding voltage being output during processing of said wafer; and a declamping voltage during a declamping period to substantially remove said clamping force, said declamping voltage having a polarity that is opposite to said first polarity.
Claim 2
Dependent Claim
218 words
A control system for controlling a direct current power supply, said direct current power supply supplying direct current voltages to a pole of an electrostatic chuck having a substantially resistive dielectric layer disposed thereon to clamp a wafer to said electrostatic chuck, comprising: a control circuit electrically coupled to said direct current power supply for causing said direct current power supply to output said direct current voltages at: a build-up voltage having a first polarity during a build-up period to cause a potential difference to build up between a first region of said substantially resistive dielectric layer and a second region of said wafer that overlies at least a portion of said first region, said potential difference giving rise to a clamping force to clamp said wafer to said electrostatic chuck, said build-up period terminating when said clamping force substantially reaches a predefined level; a holding voltage during a holding period to substantially maintain said clamping force at said predefined level, said holding voltage having said first polarity and a magnitude that is lower than a magnitude of said build-up voltage, said holding voltage being output during processing of said wafer; and a declamping voltage during a declamping period to substantially remove said clamping force, said declamping voltage having a polarity that is opposite to said first polarity.
Claim 3
Dependent Claim
33 words
The control system of claim 1 wherein said clamping force represents an electrostatic force between said wafer and said chuck that is sufficient to stabilize thermal transfer at a predefined level during processing.
Claim 4
Dependent Claim
21 words
The control system of claim 1 wherein a magnitude of said declamping voltage substantially equals said magnitude of said build-up voltage.
Claim 5
Dependent Claim
15 words
The control system of claim 1 wherein said electrostatic chuck is a bipolar electrostatic chuck.
Claim 6
Dependent Claim
33 words
The control system of claim 4 further comprising a bias compensation circuit coupled to said control circuit for adjusting said direct current voltages responsive to an induced direct current bias on said wafer.
Claim 7
Dependent Claim
36 words
The control system of claim 1 wherein at least one of said build-up voltage, said holding voltage, and said declamping voltage is generated responsive to signals from a digital processing apparatus coupled to said control circuit.
Claim 8
Dependent Claim
31 words
The control system of claim 6 wherein at least one of said build-up period, said holding period, and said declamping period is generated responsive to signals from said digital processing apparatus.
Claim 9
Dependent Claim
15 words
The control system of claim 1 wherein said control circuit represents an analog control circuit.
Claim 10
Dependent Claim
19 words
The control system of claim 1 wherein said declamping period ends when said potential difference is about zero volt.
Claim 11
Dependent Claim
20 words
The control system of claim 1 wherein said build up voltage level is supplied by a substantially square wave pulse.
Claim 12
Independent Claim
159 words
A method for clamping a wafer to an electrostatic chuck having a substantially resistive dielectric layer disposed thereon, comprising: providing a build-up voltage having a first polarity to a pole of said electrostatic chuck to cause a potential difference to build up between a first region of said substantially resistive dielectric layer and a second region of said wafer that overlies at least a portion of said first region, said potential difference giving rise to a clamping force to clamp said wafer to said electrostatic chuck; terminating said step of providing said build-up voltage when said clamping force substantially reaches a predefined level; and providing a holding voltage to said pole of said electrostatic chuck to substantially maintain said clamping force at said predefined level, said holding voltage having said first polarity and a magnitude that is lower than a magnitude of said build-up voltage, wherein step of providing the holding voltage is applied during processing of said wafer.
Claim 13
Independent Claim
159 words
A method for clamping a wafer to an electrostatic chuck having a substantially resistive dielectric layer disposed thereon, comprising: providing a build-up voltage having a first polarity to a pole of said electrostatic chuck to cause a potential difference to build up between a first region of said substantially resistive dielectric layer and a second region of said wafer that overlies at least a portion of said first region, said potential difference giving rise to a clamping force to clamp said wafer to said electrostatic chuck; terminating said step of providing said build-up voltage when said clamping force substantially reaches a predefined level; and providing a holding voltage to said pole of said electrostatic chuck to substantially maintain said clamping force at said predefined level, said holding voltage having said first polarity and a magnitude that is lower than a magnitude of said build-up voltage, wherein step of providing the holding voltage is applied during processing of said wafer.
Claim 14
Dependent Claim
40 words
The method of claim 11 further comprising the step of providing a declamping voltage to said pole of said electrostatic chuck to substantially remove said clamping force, said declamping voltage having a polarity that is opposite to said first polarity.
Claim 15
Dependent Claim
20 words
The method of claim 12 wherein a magnitude of said declamping voltage substantially equals said magnitude of said build-up voltage.
Claim 16
Dependent Claim
35 words
The method of claim 12 wherein at least one of said build-up voltage, said holding voltage, and said declamping voltage is generated responsive to signals from a digital processing apparatus coupled to said control circuit.
Claim 17
Dependent Claim
34 words
The method of claim 12 wherein at least one of said build-up voltage, said holding voltage, and said declamping voltage is generated responsive to signals from an analog circuit coupled to said control circuit.
Claim 18
Dependent Claim
35 words
The method of claim 12 further comprising the step of adjusting at least one of said build-up voltage, said holding voltage, and said declamping voltage responsive to an induced direct current bias on said wafer.
Claim 19
Dependent Claim
33 words
The method of claim 11 wherein said clamping force represents an electrostatic force between said wafer and said chuck that is sufficient to facilitate stable thermal transfer at a predefined level during processing.
Claim 20
Dependent Claim
14 words
The method of claim 11 wherein said electrostatic chuck is a bipolar electrostatic chuck.
Claim 21
Dependent Claim
26 words
The method of claim 11 further comprising the step of terminating said step of providing said declamping voltage when said potential difference is about zero volt.
Claim 22
Dependent Claim
17 words
The method of claim 11 wherein said build-up voltage is provided as a substantially square wave pulse.
Claim 23
Independent Claim
246 words
An apparatus for controlling a direct current power supply, said direct current power supply supplying voltages to an electrostatic chuck having a substantially resistive dielectric layer disposed thereon to effect clamping of a wafer to said electrostatic chuck, comprising: means, coupled to said direct current power supply, for generating a first control signal, said direct current power supply providing, responsive to said first control signal, a build-up voltage having a first polarity to a pole of said electrostatic chuck to cause a potential difference to build up between a first region of said substantially resistive dielectric layer and a second region of said wafer that overlies at least a portion of said first region, said potential difference giving rise to a clamping force to clamp said wafer to said electrostatic chuck; means, coupled to said direct current power supply, for generating a second control signal, said direct current power supply terminating, responsive to said second control signal, said build-up voltage when said clamping force substantially reaches a predefined level; and means, coupled to said direct current power supply, for generating a third control signal, said direct current power supply providing, responsive to said third control signal, a holding voltage to said pole of said electrostatic chuck to substantially maintain said clamping force at said predefined level, said holding voltage having said first polarity and a magnitude that is lower than a magnitude of said build-up voltage, the holding voltage being provided during processing of said wafer.
Claim 24
Independent Claim
246 words
An apparatus for controlling a direct current power supply, said direct current power supply supplying voltages to an electrostatic chuck having a substantially resistive dielectric layer disposed thereon to effect clamping of a wafer to said electrostatic chuck, comprising: means, coupled to said direct current power supply, for generating a first control signal, said direct current power supply providing, responsive to said first control signal, a build-up voltage having a first polarity to a pole of said electrostatic chuck to cause a potential difference to build up between a first region of said substantially resistive dielectric layer and a second region of said wafer that overlies at least a portion of said first region, said potential difference giving rise to a clamping force to clamp said wafer to said electrostatic chuck; means, coupled to said direct current power supply, for generating a second control signal, said direct current power supply terminating, responsive to said second control signal, said build-up voltage when said clamping force substantially reaches a predefined level; and means, coupled to said direct current power supply, for generating a third control signal, said direct current power supply providing, responsive to said third control signal, a holding voltage to said pole of said electrostatic chuck to substantially maintain said clamping force at said predefined level, said holding voltage having said first polarity and a magnitude that is lower than a magnitude of said build-up voltage, the holding voltage being provided during processing of said wafer.
Claim 25
Dependent Claim
62 words
The apparatus of claim 21 further comprising means, coupled to said direct current power supply, for generating a fourth control signal, said direct current power supply providing, responsive to said fourth control signal, a declamping voltage to said pole of said electrostatic chuck to substantially remove said clamping force, said declamping voltage having a polarity that is opposite to said first polarity.
Claim 26
Dependent Claim
20 words
The apparatus of claim 22 wherein a magnitude of said declamping voltage substantially equals said magnitude of said build-up voltage.
Claim 27
Dependent Claim
41 words
The apparatus of claim 22 further comprising means, coupled to said direct current power supply, for adjusting at least one of said build-up voltage, said holding voltage, and said declamping voltage responsive to an induced direct current bias on said wafer.
Claim 28
Dependent Claim
22 words
The control system of claim 1 wherein the magnitude of said declamping voltage is greater than a magnitude of the holding voltage.
Claim 29
Dependent Claim
21 words
The control system of claim 25 wherein said declamping voltage magnitude is greater than twice said magnitude of said holding voltage.
Claim 30
Dependent Claim
21 words
The method of claim 12 wherein the magnitude of said declamping voltage is greater than a magnitude of the holding voltage.
Claim 31
Dependent Claim
20 words
The method of claim 27 wherein said declamping voltage magnitude is greater than twice said magnitude of said holding voltage.
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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) | 2001-08-10 | 2002-02-09 | 2002-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-10 | 2006-02-09 | 2006-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-10 | 2010-02-09 | 2010-08-11 | $7700.00 | Window Closed / Lapsed |