Patent US4923645A successfully refreshed from Google Patents.
US4036723A
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RF bias sputtering method for producing insulating films free of surface irregularities
Assignee: International Business Machines Corp
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Filing: 1976-06-01
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Granted: 1977-07-19
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Expires: 1996-06-01
Abstract
Abstract An insulating film substantially free from surface irregularities is RF bias sputtered onto a smooth polycrystalline or micro-roughened surface. Controlled sputtering is performed first at a low reemission coefficient and then, after a substantially continuous layer of insulative amorphous film is deposited over the substrate, increasing the reemission coefficient to a second higher level. A low reemission coefficient is about 0.25 and a high coefficient is about 0.7.
Inventors
- 👤 Bradford Clyde Schwartz
- 👤 Ralph Donald Silkensen
- 👤 Gerald Steving
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:15
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/02; C23C14/024; C23C14/22; C23C14/34
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
111 words
In the method of forming an electrically insulative coating having a surface smoothness value of 250 A or less, peak to valley, over a polycrystalline or a microroughened substrate having surface irregularities of as great as 500 A, the steps of: Rf bias sputtering a first substantially continuous layer of electrically insulative material over said substrate at a reemission coefficient of about 0.35 or lower; and then Rf bias sputtering a second layer of said electrically insulative material over said first layer of electrically insulative material at a reemission coefficient of about 0.6 or greater to provide a surface smoothness of at least about 250 A, peak to valley, or smoother.
Claim 2
Dependent Claim
111 words
In the method of forming an electrically insulative coating having a surface smoothness value of 250 A or less, peak to valley, over a polycrystalline or a microroughened substrate having surface irregularities of as great as 500 A, the steps of: Rf bias sputtering a first substantially continuous layer of electrically insulative material over said substrate at a reemission coefficient of about 0.35 or lower; and then Rf bias sputtering a second layer of said electrically insulative material over said first layer of electrically insulative material at a reemission coefficient of about 0.6 or greater to provide a surface smoothness of at least about 250 A, peak to valley, or smoother.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein said polycrystalline substrate is a ceramic.
Claim 4
Dependent Claim
10 words
The method of claim 2 wherein said ceramic is ferrite.
Claim 5
Dependent Claim
12 words
The method of claim 1 wherein said electrically insulative material is amorphous.
Claim 6
Dependent Claim
30 words
The method of claim 4 wherein said electrically insulative material selected from the group consisting of Al 2 O 3 , SiO 2 , and Si 3 N 4 .
Claim 7
Dependent Claim
26 words
The method of claim 4 wherein sputtering of said first electrically insulative layer is at a reemission coefficient in the range of about 0.15 to 0.35.
Claim 8
Dependent Claim
31 words
The method of claim 1 wherein said electrically insulative material is selected from the group consisting of Al 2 O 3 , SiO 2 , and Si 3 N 4 .
Claim 9
Dependent Claim
24 words
The method of claim 7 wherein said second insulative layer is sputtered at a reemission coefficient in the range of about 0.6 to 0.8.
Claim 10
Dependent Claim
22 words
The method of claim 1 wherein said first electrically insulative layer is sputtered at a reemission coefficient of about 0.15 to 0.35.
Claim 11
Dependent Claim
19 words
The method of claim 1 wherein said first insulative layer is sputtered at a reemission coefficient of about 0.25.
Claim 12
Dependent Claim
25 words
The method of claim 1 wherein said second electrically insulative layer is sputtered at a reemission coefficient in the range of about 0.6 to 0.8.
Claim 13
Dependent Claim
42 words
The method of claim 1 wherein said insulative layer having a surface smoothness value of about 250 A or less, peak to valley, is partially coated with material in the form of a raised pattern having a thickness of about 500 A.
Claim 14
Dependent Claim
10 words
The method of claim 12 wherein said material is magnetic.
Claim 15
Dependent Claim
58 words
The method of claim 13 wherein said magnetic material is permalloy exhibiting an H ce of about 1.5 oe or less, an H k within the range of about 2.5 to 5.5 oe, and an H ch of about 1.5 oe or less, a β of about 5° or less, and an α of about 10° or less.
Claim 16
Dependent Claim
92 words
The method of claim 12 wherein said insulative layer having a surface smoothness value of about 250 A or less, peak to valley, is partially coated with metallic magnetic permalloy in the form of a raised line pattern having a thickness of about 500 A and exhibiting an H ce of about 1.5 oe or less, an H k within the range of about 2.5 to 5.5 oe, an H ch of about 1.5 oe or less, a β of about 5° or less, and an α of about 10° or less.
Claim 17
Dependent Claim
104 words
In the method of forming an electrically insulative coating having a surface smoothness value of about 250 A or less, peak to valley, over a polycrystalline ferrite substrate, the steps of: Rf bias sputtering a first substantially continuous layer of electrically insulative amorphous Al 2 O 3 over said ferrite at a reemission coefficient of about 0.25; Rf bias sputtering a second layer of electrically insulative Al 2 O 3 over said first layer of electrically insulative amorphous Al 2 O 3 at a reemission coefficient of about 0.7 to provide a surface smoothness value of about 250 A or less, peak to valley.
Claim 18
Dependent Claim
104 words
In the method of forming an electrically insulative coating having a surface smoothness value of about 250 A or less, peak to valley, over a polycrystalline ferrite substrate, the steps of: Rf bias sputtering a first substantially continuous layer of electrically insulative amorphous Al 2 O 3 over said ferrite at a reemission coefficient of about 0.25; Rf bias sputtering a second layer of electrically insulative Al 2 O 3 over said first layer of electrically insulative amorphous Al 2 O 3 at a reemission coefficient of about 0.7 to provide a surface smoothness value of about 250 A or less, peak to valley.
Claim 19
Dependent Claim
113 words
In the method of forming an electrically insulative coating having a surface smoothness value of about 250 A or less, peak to valley, over a substrate having a raised pattern having a thickness of about 500 A, the steps of: Rf bias sputtering a first substantially continuous layer of electrically insulative material over said substrate and raised pattern at a reemission coefficient of about 0.35 or lower; and then Rf bias sputtering a second layer of said electrically insulative material over said first layer of said electrically insulative material at a reemission coefficient of about 0.6 or greater, to provide a surface smoothness value of about 250 A or less, peak to valley.
Claim 20
Dependent Claim
113 words
In the method of forming an electrically insulative coating having a surface smoothness value of about 250 A or less, peak to valley, over a substrate having a raised pattern having a thickness of about 500 A, the steps of: Rf bias sputtering a first substantially continuous layer of electrically insulative material over said substrate and raised pattern at a reemission coefficient of about 0.35 or lower; and then Rf bias sputtering a second layer of said electrically insulative material over said first layer of said electrically insulative material at a reemission coefficient of about 0.6 or greater, to provide a surface smoothness value of about 250 A or less, peak to valley.
Claim 21
Dependent Claim
62 words
The method of claim 17 wherein the raised pattern includes magnetic material, the first layer of electrically insulative material is sputtered at a reemission coefficient in the range of about 0.15 to 0.35, and is amorphous, and wherein said insulative material is selected from the group consisting of Al 2 O 3 , SiO 2 , and Si 3 N 4 .
Claim 22
Dependent Claim
58 words
The method of claim 18 wherein said magnetic material is permalloy exhibiting an H ce of about 1.5 oe or less, an H k within the range of about 2.5 to 5.5 oe, and an H ch of about 1.5 oe or less, a β of about 5° or less, and an α of about 10° or less.
Claim 23
Dependent Claim
38 words
The method of claim 19 wherein a magnetic head is formed by forming conductive connections to said permalloy, coating said permalloy and conductive connections with insulation, and placing additional ferrite on the insulation to form a magnetic head.
Claim 24
Dependent Claim
20 words
The method of claim 17 wherein the reemission coefficient for sputtering of the second layer is no greater than 0.8.
Claim 25
Dependent Claim
18 words
The method of claim 17 wherein the reemission coefficient for sputtering the first layer is at least 0.15.
References Cited (Backward Citations)
US3983022A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-18 | 1981-01-17 | 1981-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-18 | 1985-01-17 | 1985-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-18 | 1989-01-17 | 1989-07-19 | $7700.00 | Window Closed / Lapsed |