US4963239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sputtering process and an apparatus for carrying out the same
Assignee: Hitachi Ltd
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Filing: 1989-01-26
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Granted: 1990-10-16
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Expires: 2009-01-26
Abstract
Abstract A sputtering process of a substrate biasing system and an apparatus for carrying out the same, capable of forming a film in satisfactory surface coverage over stepped underlying layer. The present invention solves problems in the quality of films formed by the conventional sputtering process of a substrate biasing system by regulating the bias potential of a substrate on which a film is to be formed so that the kinetic energy of ions of a sputtering gas falling on the substrate is varied periodically. The bias potential is regulated by periodically varying the amplitude of the output of a radio frequency (or dc) bias power supply or by changing the duty factor of a voltage pulse stream of the output of the radio frequency (or dc) bias power supply.
Inventors
- 👤 Hideaki Shimamura
- 👤 Masao Sakata
- 👤 Shigeru Kobayashi
- 👤 Yuji Yoneoka
- 👤 Tsuneaki Kamei
- 👤 Tsuneyoshi Kawahito
- 👤 Shoyo Fujita
- 👤 Hiroshi Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:58
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/22; C23C14/34; C23C14/3435; C23C14/345; H; H01; H01J; H01J37/00; H01J37/32; H01J37/32431; H01J37/32697; H01J37/32706; H01J37/34
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
67 words
A sputtering process comprising continuously applying a bias voltage having a single polarity to a substrate electrode in a vacuum atmosphere during forming of a film over the surface of a substrate, varying the applied bias voltage and controlling a duty factor of the applied bias voltage so that the magnitude of the kinetic energy of ions of a sputtering gas impacting the substrate is varied periodically.
Claim 2
Dependent Claim
67 words
A sputtering process comprising continuously applying a bias voltage having a single polarity to a substrate electrode in a vacuum atmosphere during forming of a film over the surface of a substrate, varying the applied bias voltage and controlling a duty factor of the applied bias voltage so that the magnitude of the kinetic energy of ions of a sputtering gas impacting the substrate is varied periodically.
Claim 3
Dependent Claim
19 words
A sputtering process according to claim 1, wherein the waveform of said bias voltage is a voltage pulse stream.
Claim 4
Dependent Claim
27 words
A sputtering process according to claim 2, wherein the step of said voltage pulse is always on the negative side of the floating voltage of the substrate.
Claim 5
Dependent Claim
29 words
A sputtering process according to claim 2, wherein the form of the voltage pulse stream of said bias voltage is varied during one portion of a film forming operation.
Claim 6
Dependent Claim
18 words
A sputtering process according to claim 1, wherein the said bias voltage is a radio frequency bias voltage.
Claim 7
Dependent Claim
31 words
A sputtering process according to claim 5, wherein the average voltage waveform with respect to time of said bias voltage is a waveform of a frequency not higher than 1 MHz.
Claim 8
Dependent Claim
100 words
A sputtering process according to claim 5, wherein a waveform of an average voltage determined from a first envelope passing through a plurality of upper peak points of a voltage waveform of said bias voltage, and a second envelope passing through a plurality of lower peak points of the voltage waveform of said bias voltage is controlled such that the average voltage is of a negative polarity in a period where the amplitude of said radio frequency bias voltage is at a maximum and in a period where the amplitude of said radio frequency bias voltage is at a minimum.
Claim 9
Dependent Claim
54 words
A sputtering process according to claim 7, wherein the carrier of the voltage waveform of said bias voltage is a radio frequency wave of 5 MHz or higher, and the repetition frequency of first and second envelopes passing through the peak points of the voltage waveform of the carrier is 1 MHz or lower.
Claim 10
Dependent Claim
25 words
A sputtering process according to claim 5, wherein the voltage waveform of said bias voltage is varied during one portion of a film forming operation.
Claim 11
Dependent Claim
41 words
A sputtering process according to claim 1, further comprising optionally changing the position of a plasma by varying the ratio between currents supplied respectively to a plurality of annular exciting coils disposed coaxially with a target used to produce sputtered particles.
Claim 12
Dependent Claim
21 words
A sputtering process according to claim 1, further comprising utilizing a filter for giving directivity to particles sputtered from a target.
Claim 13
Dependent Claim
24 words
A sputtering process according to claim 11, wherein the variation of voltage applied to said filter is synchronous with that of said bias voltage.
Claim 14
Dependent Claim
142 words
A sputtering apparatus comprising: a vacuum vessel; a sputtering electrode disposed within the vacuum vessel; a sputtering power supply connected to the sputtering electrode; evacuating means for evacuating the vacuum vessel; sputtering gas supply means; a substrate bias electrode for holding a substrate on which a film is to be formed and for continuously applying a bias voltage having a single polarity to the substrate; a bias voltage power supply means for continuously applying the bias voltage of a single polarity to the substrate bias electrode for application to the substrate and for controlling the intensity of ions of a sputtering gas on the substrate; and means for varying the applied bias voltage and for controlling the duty factor of the applied bias voltage so that the kinetic energy of the ions of the sputtering gas impacting the substrate is varied periodically.
Claim 15
Dependent Claim
142 words
A sputtering apparatus comprising: a vacuum vessel; a sputtering electrode disposed within the vacuum vessel; a sputtering power supply connected to the sputtering electrode; evacuating means for evacuating the vacuum vessel; sputtering gas supply means; a substrate bias electrode for holding a substrate on which a film is to be formed and for continuously applying a bias voltage having a single polarity to the substrate; a bias voltage power supply means for continuously applying the bias voltage of a single polarity to the substrate bias electrode for application to the substrate and for controlling the intensity of ions of a sputtering gas on the substrate; and means for varying the applied bias voltage and for controlling the duty factor of the applied bias voltage so that the kinetic energy of the ions of the sputtering gas impacting the substrate is varied periodically.
Claim 16
Dependent Claim
20 words
A sputtering apparatus according to claim 13, wherein the voltage waveform of said bias voltage is a voltage pulse stream.
Claim 17
Dependent Claim
21 words
A sputtering apparatus according to claim 13, wherein the voltage waveform of said bias voltage is a radio frequency voltage waveform.
Claim 18
Dependent Claim
27 words
A sputtering apparatus according to claim 15, wherein the tim-average voltage waveform of said bias voltage is a waveform of a frequency of 1 MHz or below.
Claim 19
Dependent Claim
104 words
A sputtering apparatus according to claim 15, wherein a waveform of an average voltage determined from a first envelope passing through a plurality of upper peak points of a voltage waveform of said bias voltage, and a second envelope passing through a plurality of lower peak points of the voltage waveform of said bias voltage is controlled such that the average voltage is of a negative polarity during a period where the amplitude of the waveform of said radio frequency bias voltage is a maximum and during a period where the amplitude of the waveform of said radio frequency bias voltage is a minimum.
Claim 20
Dependent Claim
56 words
A sputtering apparatus according to claim 17, wherein the carrier wave of the voltage waveform of said bias voltage is a radio frequency wave of 5 MHz or higher, and the repetition frequency of the voltage waveforms of first and second envelopes passing respectively through peak points of the carrier wave is 1 MHz or below.
Claim 21
Dependent Claim
34 words
A sputtering apparatus according to claim 13, wherein said bias voltage includes a plurality of voltage pulses having a step which is always on the negative side of the floating voltage of the substrate.
Claim 22
Dependent Claim
50 words
A sputtering apparatus according to claim 13, further comprising a sputtering mechanism including a plurality of annular exciting coils disposed coaxially with the sputtering electrode and capable of optionally changing the position of a plasma by varying the ratios between currents supplied respectively to the plurality of annular exciting coils.
Claim 23
Dependent Claim
21 words
A sputtering apparatus according to claim 13, further comprising utilizing a filter for giving, directivity to particles sputtered from a target.
Claim 24
Dependent Claim
25 words
A sputtering apparatus according to claim 21, wherein the variation of the voltage applied to said filter is synchronous with that of the bias voltage.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-10-15 | 1994-04-16 | 1994-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-15 | 1998-04-16 | 1998-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-15 | 2002-04-16 | 2002-10-16 | $7700.00 | Window Closed / Lapsed |