Patent US6079426A successfully refreshed from Google Patents.
US6079426A
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Method and apparatus for determining the endpoint in a plasma cleaning process
Assignee: Applied Materials Inc
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Filing: 1997-07-02
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Granted: 2000-06-27
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Expires: 2017-07-02
Abstract
Abstract Apparatus and methods are disclosed for utilizing a plasma cleaning operation of a CVD system incorporating cleaning process endpoint detection. In one embodiment, the cleaning process is performed at a constant exhaust capacity and the endpoint detection is in response to a specified rate of change of chamber pressure. In another embodiment, a servo-controlled exhaust system maintains a controlled chamber pressure and the endpoint detection is in response to a specified control signal. In a preferred embodiment, nitrogen trifluoride is converted into a plasma containing free fluorine radicals in a magnetron-powered remote microwave plasma generator. The remotely produced free fluorine radicals are used to remove silicon nitride deposits from a substrate processing chamber. The use of such a remote plasma system provides an efficient cleaning process that takes as little as half the time compared to similar in situ plasma cleaning processes. The incorporation of endpoint detection provides optimal cleaning time for the remote plasma cleaning process.
Inventors
- 👤 Sudhakar Subrahmanyam
- 👤 Tsutomu Tanaka
- 👤 Mukul Kelkar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:37
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32917; H01J37/32935; C; C23; C23C; C23C16/00; C23C16/44; C23C16/4401; C23C16/4405; H01J37/32963; H01J2237/00; H01J2237/32; H01J2237/33; H01J2237/335; Y; Y10; Y10S; Y10S156/00; Y10S156/916
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
70 words
A method of cleaning silicon nitride deposits from a substrate processing chamber, the method comprising: (a) exposing a chamber to a plasma formed from a cleaning gas to clean the silicon nitride deposits from the substrate processing chamber; (b) measuring a pressure level wit said chamber to determine a specified rate of change of pressure; and (c) extinguishing said plasma in response to said specified rate of change of pressure.
Claim 2
Independent Claim
70 words
A method of cleaning silicon nitride deposits from a substrate processing chamber, the method comprising: (a) exposing a chamber to a plasma formed from a cleaning gas to clean the silicon nitride deposits from the substrate processing chamber; (b) measuring a pressure level wit said chamber to determine a specified rate of change of pressure; and (c) extinguishing said plasma in response to said specified rate of change of pressure.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein said cleaning gas includes at least one halogen element.
Claim 4
Dependent Claim
13 words
The method of claim 2 wherein said cleaning gas comprises NF 3 .
Claim 5
Dependent Claim
20 words
The method of claim 1 therein said specified rate of change of pressure is essentially a zero rate of change.
Claim 6
Dependent Claim
20 words
The method of claim 1 wherein said extinguishing of said plasma is accomplished by turning off a plasma power supply.
Claim 7
Independent Claim
63 words
A method of cleaning deposits from a substrate processing chamber, the method comprising: (a) exposing a chamber to a plasma formed from a cleaning gas; (b) measuring a pressure level within said chamber to determine a specified rate of change of pressure; (c) waiting a period of time; and (d) extinguishing said plasma in response to said specified rate of change of pressure.
Claim 8
Independent Claim
63 words
A method of cleaning deposits from a substrate processing chamber, the method comprising: (a) exposing a chamber to a plasma formed from a cleaning gas; (b) measuring a pressure level within said chamber to determine a specified rate of change of pressure; (c) waiting a period of time; and (d) extinguishing said plasma in response to said specified rate of change of pressure.
Claim 9
Dependent Claim
23 words
The method of claim 6 wherein said plasma flows from said remote microwave plasma generator into said chamber through a gas distribution faceplate.
Claim 10
Dependent Claim
32 words
The method of claim 6 wherein said period of time is between about 5%-30% of the time between said step (a) and said determination of said specified rate of change of pressure.
Claim 11
Dependent Claim
22 words
The method of claim 1 wherein said detecting of said specified rate of change of pressure occurs after a peak chamber pressure.
Claim 12
Dependent Claim
26 words
The method of claim 1 wherein said chamber is exposed to said plasma at an initial pressure of between about 50 mtorr and about 1.5 torr.
Claim 13
Independent Claim
101 words
A method for cleaning oxide residue or nitride residue from a substrate processing chamber, the method comprising: a) exposing a chamber to a plasma formed in a remote plasma generator from a cleaning gas; b) establishing a controlled pressure in said chamber; c) monitoring a step signal to a stepper motor, said stepper motor being coupled to a valve and being capable of adjusting said valve in response to said step signal, to detect a specified rate of change of said step signal; and d) extinguishing said plasma in response to detecting said specified rate of change of said step signal.
Claim 14
Independent Claim
101 words
A method for cleaning oxide residue or nitride residue from a substrate processing chamber, the method comprising: a) exposing a chamber to a plasma formed in a remote plasma generator from a cleaning gas; b) establishing a controlled pressure in said chamber; c) monitoring a step signal to a stepper motor, said stepper motor being coupled to a valve and being capable of adjusting said valve in response to said step signal, to detect a specified rate of change of said step signal; and d) extinguishing said plasma in response to detecting said specified rate of change of said step signal.
Claim 15
Dependent Claim
19 words
The method of claim 11 wherein said controlled pressure of step (b) is between about 0.05 and 1.5 torr.
Claim 16
Dependent Claim
12 words
The method of claim 11 wherein said cleaning gas comprises a halogen.
Claim 17
Dependent Claim
11 words
The method of claim 11 wherein said cleaning gas comprises fluorine.
Claim 18
Dependent Claim
13 words
The method of claim 11 wherein said cleaning gas comprises NF 3 .
Claim 19
Dependent Claim
19 words
The method of claim 1 wherein said specified rate of change of pressure occurs essentially at a maximum pressure.
Claim 20
Dependent Claim
193 words
A substrate processing system comprising: a processing chamber; a plasma system configured to provide a plasma in said processing chamber; a gas delivery system configured to deliver a cleaning gas to said plasma system; a vacuum system configured to evacuate said processing chamber, said vacuum system including a chamber pressure sensing device producing a pressure signal; a controller configured to control said gas delivery system, said vacuum system, and said plasma system; and a memory, coupled to said controller, having a computer-readable program embedded therein for directing operation of said substrate processing system, said computer-readable program including: i) a first set of computer instructions for controlling said gas delivery system to flow said cleaning gas to said plasma system; ii) a second set of computer instructions to read said pressure signal to determine a rate of change of chamber pressure, said specified rate of change of chamber pressure being stored in said memory; iii) a third set of computer instructions for controlling said plasma system to energize said plasma system to produce a plasma from said cleaning gas, and to extinguish said plasma in response to said specified rate of change of pressure.
Claim 21
Dependent Claim
193 words
A substrate processing system comprising: a processing chamber; a plasma system configured to provide a plasma in said processing chamber; a gas delivery system configured to deliver a cleaning gas to said plasma system; a vacuum system configured to evacuate said processing chamber, said vacuum system including a chamber pressure sensing device producing a pressure signal; a controller configured to control said gas delivery system, said vacuum system, and said plasma system; and a memory, coupled to said controller, having a computer-readable program embedded therein for directing operation of said substrate processing system, said computer-readable program including: i) a first set of computer instructions for controlling said gas delivery system to flow said cleaning gas to said plasma system; ii) a second set of computer instructions to read said pressure signal to determine a rate of change of chamber pressure, said specified rate of change of chamber pressure being stored in said memory; iii) a third set of computer instructions for controlling said plasma system to energize said plasma system to produce a plasma from said cleaning gas, and to extinguish said plasma in response to said specified rate of change of pressure.
Claim 22
Dependent Claim
16 words
The method of claim 11 wherein the remote plasma generator is a remote microwave plasma generator.
Claim 23
Independent Claim
94 words
A method of cleaning silicon nitride deposits from a substrate processing chamber, the method comprising: (a) flowing NF 3 into a remote plasma generator; (b) forming a plasma from the NF 3 in the remote plasma generator, the plasma containing plasma species; (c) flowing the plasma species from the remote plasma generator into the substrate processing chamber through a gas distribution faceplate; (d) measuring a pressure level within said chamber to determine a specified rate of change of pressure; and (e) extinguishing the plasma in response to the specified rate of change of pressure.
Claim 24
Independent Claim
94 words
A method of cleaning silicon nitride deposits from a substrate processing chamber, the method comprising: (a) flowing NF 3 into a remote plasma generator; (b) forming a plasma from the NF 3 in the remote plasma generator, the plasma containing plasma species; (c) flowing the plasma species from the remote plasma generator into the substrate processing chamber through a gas distribution faceplate; (d) measuring a pressure level within said chamber to determine a specified rate of change of pressure; and (e) extinguishing the plasma in response to the specified rate of change of pressure.
Claim 25
Independent Claim
102 words
A method of cleaning silicon nitride deposits from a substrate processing chamber, the method comprising: a) flowing NF 3 into a remote plasma generator; b) forming a plasma from the NF 3 in the remote plasma generator, the plasma containing plasma species; c) flowing the plasma species from the remote plasma generator into the substrate processing chamber through a gas distribution faceplate; d) measuring a pressure level within said chamber to determine a rate of change of pressure; and e) in response to detecting a specified rate of change of pressure, waiting a selected period of time and then extinguishing the plasma.
Claim 26
Independent Claim
102 words
A method of cleaning silicon nitride deposits from a substrate processing chamber, the method comprising: a) flowing NF 3 into a remote plasma generator; b) forming a plasma from the NF 3 in the remote plasma generator, the plasma containing plasma species; c) flowing the plasma species from the remote plasma generator into the substrate processing chamber through a gas distribution faceplate; d) measuring a pressure level within said chamber to determine a rate of change of pressure; and e) in response to detecting a specified rate of change of pressure, waiting a selected period of time and then extinguishing the plasma.
Claim 27
Independent Claim
109 words
A method of cleaning silicon nitride deposits from a substrate processing chamber, the method comprising: (a) flowing NF 3 into a remote plasma generator; (b) forming a plasma from the NF 3 in the remote plasma generator, the plasma containing plasma species; (c) flowing the plasma species from the remote plasma generator into the substrate processing chamber through a gas distribution faceplate; (d) establishing a controlled pressure in the substrate processing chamber; (e) monitoring a pressure control signal to detect a specified rate of change of the pressure control signal; and (f) extinguishing the plasma in response to detecting the specified rate of change of the pressure control signal.
Claim 28
Independent Claim
109 words
A method of cleaning silicon nitride deposits from a substrate processing chamber, the method comprising: (a) flowing NF 3 into a remote plasma generator; (b) forming a plasma from the NF 3 in the remote plasma generator, the plasma containing plasma species; (c) flowing the plasma species from the remote plasma generator into the substrate processing chamber through a gas distribution faceplate; (d) establishing a controlled pressure in the substrate processing chamber; (e) monitoring a pressure control signal to detect a specified rate of change of the pressure control signal; and (f) extinguishing the plasma in response to detecting the specified rate of change of the pressure control signal.
Claim 29
Independent Claim
60 words
A method of setting a chamber operating pressure, the method comprising: (a) determining a minimum pressure attainable by each of a plurality of vacuum chamber substrate processing systems; and (b) setting a controlled pressure set-point for each of at least two of the plurality of vacuum chamber substrate processing systems, wherein the controlled pressure set-point is above the minimum pressure.
Claim 30
Independent Claim
60 words
A method of setting a chamber operating pressure, the method comprising: (a) determining a minimum pressure attainable by each of a plurality of vacuum chamber substrate processing systems; and (b) setting a controlled pressure set-point for each of at least two of the plurality of vacuum chamber substrate processing systems, wherein the controlled pressure set-point is above the minimum pressure.
Claim 31
Independent Claim
109 words
A method of detecting an endpoint of a process occurring in a substrate processing chamber having a vacuum system and a throttle valve fluidly coupled between the vacuum system and the chamber, the method comprising: (a) performing a process in the substrate processing chamber; (b) monitoring a control signal that corresponds to a position of the throttle valve; wherein said control signal is generated according to a difference between a measured value of a pressure in said process chamber and a target value for said pressure; and (c) determining an endpoint of said process in response to a behavior of said control signal; and subsequently (d) terminating said process.
Claim 32
Independent Claim
109 words
A method of detecting an endpoint of a process occurring in a substrate processing chamber having a vacuum system and a throttle valve fluidly coupled between the vacuum system and the chamber, the method comprising: (a) performing a process in the substrate processing chamber; (b) monitoring a control signal that corresponds to a position of the throttle valve; wherein said control signal is generated according to a difference between a measured value of a pressure in said process chamber and a target value for said pressure; and (c) determining an endpoint of said process in response to a behavior of said control signal; and subsequently (d) terminating said process.
Claim 33
Dependent Claim
19 words
The method of claim 23 wherein said behavior of said control signal corresponds to a constant closed loop signal.
Claim 34
Dependent Claim
22 words
The method of claim 23, wherein said (c) includes distinguishing said behavior of said control signal from an open loop control signal.
Claim 35
Dependent Claim
34 words
The method of claim 23, further comprising: between said (c) and said (d), in response to detecting a specified change of said control signal, waiting a selected period of time before terminating said process.
Claim 36
Dependent Claim
12 words
The method of claim 23, wherein said process is a cleaning process.
Claim 37
Dependent Claim
13 words
The method of claim 27, wherein said cleaning process uses a remote plasma.
Claim 38
Dependent Claim
20 words
The method of claim 28, wherein said cleaning process removes silicon nitride deposits from exposed surfaces within the processing chamber.
References Cited (Backward Citations)
JPS63129629A
Cited
US5211825A
Cited
US5252178A
Cited
JPH06224163A
Cited
US5413670A
Cited
JPH0982645A
Cited
JPH09143742A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-06-27 | 2003-12-27 | 2004-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-06-27 | 2007-12-27 | 2008-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-06-27 | 2011-12-27 | 2012-06-27 | $7700.00 | Window Closed / Lapsed |