EP0425419A2
Expired / Lapsed
EP
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Methods and apparatus for contamination control in plasma processing
Assignee: International Business Machines Corp
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Filing: 1990-09-28
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Granted: —
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Expires: 2010-09-28
Abstract
Abstract Contamination levels in plasma processes are reduced during plasma processing, by prevention of formation of particles, by preventing entry of particles externally introduced or by removing particles spontaneously formed from chemical and/or mechanical sources. Some techniques for prevention of formation of particles include interruption of the plasma by pulsing the source of plasma energy periodically, or application of energy to provide mechanical agitation such as mechanical shockwaves, acoustic stress, ultrasonic stress, vibrational stress, thermal stress, and pressure stress. Following a period of applied stress, a tool is pumped out (if a plasma is used, the glow is first discontinued), vented, opened and flaked or particulate material is cleaned from the lower electrode and other surfaces. A burst of filtered air or nitrogen, or a vacuum cleaner is used for removal of deposition debris while the vented tool is open. Following this procedure, the tool is then be used.for product runs. Alternatively, improvement of semiconductor process yields can be achieved by addition of reagents to getter chemical precursors of contamination particulates and by filtration of particulates from feedgas before plasma processing. The efficiency and endpoint for the applied stress are determined, by laser light scattering, using a pulsed or continuous laser source, e.g. a HeNe laser.
Inventors
- 👤 Reid Stuart Bennett
- 👤 Albert Rogers Ellingboe
- 👤 George Gordon Gifford
- 👤 Jyothi Singh
- 👤 Kurt Lindsay Haller
- 👤 John Slaton Mckillop
- 👤 Gary Stewart Selwyn
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 20:53
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32431; H01J37/32798; H01J37/32853; H01J37/32862; C; C23; C23C; C23C16/00; C23C16/44; C23C16/4401; C23C16/50; C23C16/515; H01J2237/00; H01J2237/02; H01J2237/022; Y; Y10; Y10S; Y10S156/00; Y10S156/916
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
35 words
A method of prevention of plasma contamination in a plasma reactor system comprising : applying electrostatic, electromagnetic, mechanical, thermal, pressure, hygroscopic or chemical means to eliminate particle contamination in situ in said plasma reactor system.
Claim 2
Independent Claim
35 words
A method of prevention of plasma contamination in a plasma reactor system comprising : applying electrostatic, electromagnetic, mechanical, thermal, pressure, hygroscopic or chemical means to eliminate particle contamination in situ in said plasma reactor system.
Claim 3
Dependent Claim
124 words
A method in accordance with claim 1 for prevention of plasma contamination comprising performing a plasma process including the steps as follows : a) applying an RF voltage to establish a plasma within said reactor, b) periodically interrupting said RF voltage for a brief interval and reestablishing said RF voltage after said brief interval, providing a series of momentary interruptions of said RF voltage and said plasma periodically, between longer periods of time during which said RF voltage is applied causing said plasma to be applied in said reactor during said longer periods, and c) continuously repeating the application of said RF voltage to said reactor interrupted by said brief intervals of interruption of said RF voltage until the completion of said plasma process.
Claim 4
Dependent Claim
46 words
A method in accordance with claim 1 wherein forces are applied within said reactor for moving particles potentially leading to contamination across said plasma reactor to a space separate from the active region of said reactor to reduce contamination within said active region of said reactor.
Claim 5
Dependent Claim
23 words
A method in accordance with claim 3 comprising moving particle contamination across, said plasma reactor by the use of a directed electromagnetic wave.
Claim 6
Dependent Claim
22 words
A method in accordance with claim 3 comprising : moving particle contamination across said plasma reactor by the use of standing waves.
Claim 7
Dependent Claim
15 words
A method in accordance with claim 5 wherein said standing waves comprise an electromagnetic waves.
Claim 8
Dependent Claim
17 words
A method in accordance with claim 6 wherein said standing electromagnetic waves have a controllable phase shift.
Claim 9
Dependent Claim
28 words
A method in accordance with claim 6 wherein said electromagnetic waves comprise a microwave field having a controllable phase shift from opposite regions of regions of said reactor.
Claim 10
Dependent Claim
29 words
A method in accordance with claim 3 comprising moving particle contamination across a plasma reactor to reduce contamination by the use of a pulsed, continuous or ramped magnetic field.
Claim 11
Dependent Claim
26 words
A method in accordance with claim 3 comprising moving particle contamination across a plasma reactor to reduce contamination by the use of a directed acoustic wave.
Claim 12
Dependent Claim
26 words
A method in accordance with claim 3 comprising moving particle contamination across a plasma reactor to reduce contamination by the use gf a standing acoustic wave.
Claim 13
Dependent Claim
29 words
A method in accordance with claim 3 comprising moving particle contamination across a plasma reactor to reduce contamination by the use of an acoustic wave generated by a transducer.
Claim 14
Dependent Claim
34 words
A method in accordance with claim 3 comprising moving particle contamination across a plasma reactor to reduce contamination by the use of an acoustic wave generated by a pulsed gas flux in the tool.
Claim 15
Dependent Claim
37 words
A method in accordance with claim 3 comprising moving particle contamination across a plasma reactor to reduce contamination by the use of a standing acoustic wave generated by two transducers located on opposite sides of said reactor.
Claim 16
Dependent Claim
24 words
A method in accordance with claim 3 comprising moving particle contamination across said plasma reactor to reduce contamination by the use of particle beams.
Claim 17
Dependent Claim
25 words
A method in accordance with claim 3 comprising moving particle contamination across said plasma reactor to reduce contamination by the use of electromagnetic radiation pressure.
Claim 18
Dependent Claim
20 words
A method in accordance with claim 16 wherein said electromagnetic radiation pressure comprises light from lasers or incoherent light sources.
Claim 19
Dependent Claim
25 words
A method in accordance with claim 3 comprising moving particle contamination across said plasma reactor to reduce contamination by the use of a thermal gradient.
Claim 20
Dependent Claim
27 words
A method in accordance with claim 1 wherein a stress is applied to said plasma reactor to remove said particles from said reactor walls and electrode surfaces.
Claim 21
Dependent Claim
34 words
A method in accordance with claim 19 wherein said stress comprises an energy field mechanically agitating said reactor to transfer energy to said particles, whereby said particles are prepared for removal from said reactor.
Claim 22
Dependent Claim
14 words
A method in accordance with claim 19 wherein said stress comprises a mechanical shockwave.
Claim 23
Dependent Claim
14 words
A method in accordance with claim 19 wherein said stress comprises an acoustic stress.
Claim 24
Dependent Claim
14 words
A method in accordance with claim 19 wherein said stress comprises an ultrasonic stress.
Claim 25
Dependent Claim
14 words
A method in accordance with claim 19 wherein said stress comprises a vibrational stress.
Claim 26
Dependent Claim
14 words
A method in accordance with claim 19 wherein said stress comprises a thermal stress.
Claim 27
Dependent Claim
14 words
A method in accordance with claim 19 wherein said stress comprises a pressure stress.
Claim 28
Independent Claim
146 words
A method for performing a plasma procless including the steps as follows a) loading a work piece into an RF plasma chamber, b) applying an RF voltage to establish a plasma within said chamber, said plasma being exposed to said work piece to perform a plasma process upon at least one surface of said work piece, c) periodically interrupting said RF voltage for a brief interval and reestablishing said RF voltage after said brief interval, providing a series of momentary interruptions of said RF voltage and said plasma periodically, between longer periods of time during which said RF voltage is applied causing said plasma to be applied to said work piece during said longer periods, and d) continuously repeating the application of said RF voltage to said chamber interrupted by said brief intervals of interruption of said RF voltage until the completion of said plasma process.
Claim 29
Independent Claim
146 words
A method for performing a plasma procless including the steps as follows a) loading a work piece into an RF plasma chamber, b) applying an RF voltage to establish a plasma within said chamber, said plasma being exposed to said work piece to perform a plasma process upon at least one surface of said work piece, c) periodically interrupting said RF voltage for a brief interval and reestablishing said RF voltage after said brief interval, providing a series of momentary interruptions of said RF voltage and said plasma periodically, between longer periods of time during which said RF voltage is applied causing said plasma to be applied to said work piece during said longer periods, and d) continuously repeating the application of said RF voltage to said chamber interrupted by said brief intervals of interruption of said RF voltage until the completion of said plasma process.
Claim 30
Independent Claim
80 words
A method of removing contamination from a plasma reactor comprising removing a deposit layer on an inner surface of said reactor comprising contamination within a plasma reactor by application to said chamber of an external stress, at a time between successive times of operation of said plasma within said reactor, said applied stress being sufficient tp cause fracture of said deposit layer on the surfaces of said chamber and to cause flakes or particles to be loosened from said surfaces.
Claim 31
Independent Claim
80 words
A method of removing contamination from a plasma reactor comprising removing a deposit layer on an inner surface of said reactor comprising contamination within a plasma reactor by application to said chamber of an external stress, at a time between successive times of operation of said plasma within said reactor, said applied stress being sufficient tp cause fracture of said deposit layer on the surfaces of said chamber and to cause flakes or particles to be loosened from said surfaces.
Claim 32
Dependent Claim
31 words
A method in accordance with claim 1 of reducing particulate contamination in process plasmas by addition of trace amounts of the order of less than about 5% of fluorinated feed gas.
Claim 33
Dependent Claim
33 words
A method in accordance with claim 1 of reducing particulate contamination in process plasmas by addition of trace amounts of the order of less than about 5% of CF₄ or NF₃ feed gas.
Claim 34
Dependent Claim
30 words
A method in accordance with claim 1 of reducing water, oxygen or absorbed organic chemicals from the interiors of said reactor with a pre-process plasma exposure with a reactive gas.
Claim 35
Dependent Claim
33 words
A method in accordance with claim 31 comprising pre-process exposure of CF₄ or NF₃ plasmas whereby reduction in the water, oxygen or absorbed organic chemicals from the interiors of plasma chambers is achieved.
Claim 36
Dependent Claim
28 words
A method in accordance with claim 1 of reducing water content of process feed gas by the use of a hygroscopic filter prior to entering the process chamber.
Claim 37
Dependent Claim
29 words
A method in accordance with claim 33 of reducing water content of process feed gas by the use of a silica gel filter prior to entering the process chamber.
Claim 38
Dependent Claim
38 words
A method in accordance with claim 33 of reducing water content of process feed gas by the mixture of small amounts of SiF₄ with the process gases, before the silica gel filter prior to entering the process chamber.
Claim 39
Dependent Claim
60 words
A method in accordance with claim 33 comprising mixing into the feed gas a mixture of small amounts of SiF₄ with the process gases, in the presence of an inductive plasma in the silica gel filter prior to introduction of the feed gases into the processing chamber, whereby the water and hydrogenous material content of said feed gas is reduced.
Claim 40
Dependent Claim
51 words
A method in accordance with claim 1 including the steps of a) exposing said reactor to a coherent eight source for producing in situ light scattering in said reactor, and b) detecting said light scattering within said reactor whereby contamination inside said reactor can be measured by analyzing said light scattering.
Claim 41
Dependent Claim
20 words
A method in accordance with claim 37 wherein said coherent light source comprises a HeNe laser or a diode laser.
Claim 42
Dependent Claim
39 words
A method in accordance with claim 37 including producing video signals from the results of said step (b) of detecting said light scattering by employing video circuitry to detect contamination as indicated by the data signals from step b.
Claim 43
Dependent Claim
20 words
A method in accordance with claim 27 wherein the duty cycle of said RF voltage is greater than about 0.90.
Claim 44
Dependent Claim
14 words
Apparatus for implementing the method of any one of the claims 1 to 40.
References Cited (Backward Citations)
No citation records indexed.
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