Patent EP0235750A2 successfully refreshed from Google Patents.
US4443294A
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US
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Process for forming magnetic film pattern
Assignee: Hitachi Ltd
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Filing: 1982-06-09
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Granted: 1984-04-17
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Expires: 2002-06-09
Abstract
Abstract In forming a magnetic film pattern of permalloy by photoetching, the permalloy magnetic film formed on a substrate is etched in an etching solution containing ferric chloride, hydrochloric acid and phosphoric acid, thereby gradually reducing the thickness of the film pattern at the side edges in a tapered state. The permalloy magnetic film can be easily taper-etched without any deterioration of magnetic properties of permalloy magnetic film and substrate surface, but with a greatly improved yield of magnetic film head production and a greatly improved reliability.
Inventors
- 👤 Masahide Suenaga
- 👤 Yukihisa Tsukada
- 👤 Hiroshi Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:11
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16; C23F1/28; G11B5/31; G11B5/3163; H; H01; H01F; H01F41/00; H01F41/32; H01F41/34; G11B5/3109; G11B5/3116; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49036; Y10T29/49043; Y10T29/49044; Y10T29/49046
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
58 words
A process for forming a magnetic film pattern, which comprises: forming a permalloy film on a substrate, forming a mask on the permalloy film with a photoresist, etching the side edges of the permalloy film into a gradually reduced state of film thickness with an etching solution containing FeCl 3 , HCl and H 3 PO 4 .
Claim 2
Dependent Claim
58 words
A process for forming a magnetic film pattern, which comprises: forming a permalloy film on a substrate, forming a mask on the permalloy film with a photoresist, etching the side edges of the permalloy film into a gradually reduced state of film thickness with an etching solution containing FeCl 3 , HCl and H 3 PO 4 .
Claim 3
Dependent Claim
42 words
The process according to claim 1, wherein a photoresist of positive type is used as a masking material and the etching solution contains 6-24 g of FeCl 3 , 10-45 cc of HCl, and 15-110 cc of H 3 PO 4 .
Claim 4
Dependent Claim
46 words
The process according to claim 1, wherein a photoresist of positive type is used as a masking material, and the etching solution contains 10-40 g of FeCl 3 .6H 2 O, 30-130 cc of 35% HCl and 20-130 cc of 85% H 3 PO 4 .
Claim 5
Dependent Claim
20 words
The process according to claim 2 or 3, wherein the etching solution is kept at a temperature of 30°-70° C.
Claim 6
Dependent Claim
45 words
The process according to claim 1, wherein a photoresist of negative type is used as a masking material, and the etching solution contains not more than 48 g of FeCl 3 , 10-45 cc of HCl, and 15-110 cc of H 3 PO 4 .
Claim 7
Dependent Claim
49 words
The process according to claim 1, wherein a photoresist of negative type is used as a masking material, and the etching solution contains not more than 80 g of FeCl 3 .6H 2 O, 30-130 cc of 35% HCl and 20--130 cc of 85% H 3 PO 4 .
Claim 8
Dependent Claim
20 words
The process according to claim 5 or 6, wherein the etching temperature is kept at a temperature of 10°-90° C.
Claim 9
Dependent Claim
106 words
A process for producing a thin film magnetic head, which comprises: forming a permalloy film on a substrate, forming a mask on the permalloy film by a photoresist, etching the side edges of the permalloy film into a gradually reduced state of film thickness with an etching solution containing FeCl 3 , HCl and H 3 PO 4 , thereby forming a magnetic film pattern, forming a magnetoresistive film on the magnetic film pattern through an insulating film, forming a conductor with connection to the magnetoresistive film, and forming an upper magnetic layer of permalloy on the magnetoresistive film and the conductor through an insulating film.
Claim 10
Dependent Claim
106 words
A process for producing a thin film magnetic head, which comprises: forming a permalloy film on a substrate, forming a mask on the permalloy film by a photoresist, etching the side edges of the permalloy film into a gradually reduced state of film thickness with an etching solution containing FeCl 3 , HCl and H 3 PO 4 , thereby forming a magnetic film pattern, forming a magnetoresistive film on the magnetic film pattern through an insulating film, forming a conductor with connection to the magnetoresistive film, and forming an upper magnetic layer of permalloy on the magnetoresistive film and the conductor through an insulating film.
Claim 11
Dependent Claim
93 words
A process for producing a thin film magnetic head, which comprises: forming a permalloy film on a substrate, forming a mask on the permalloy film with a photoresist, etching the side edges of the permalloy film into a gradually reduced state of film thickness with an etching solution containing FeCl 3 , HCl and H 3 PO 4 , thereby forming a magnetic film pattern, forming a conductor on the magnetic film pattern through an insulating film, and forming an upper magnetic layer of permalloy film on the conductor through an insulating film.
Claim 12
Dependent Claim
93 words
A process for producing a thin film magnetic head, which comprises: forming a permalloy film on a substrate, forming a mask on the permalloy film with a photoresist, etching the side edges of the permalloy film into a gradually reduced state of film thickness with an etching solution containing FeCl 3 , HCl and H 3 PO 4 , thereby forming a magnetic film pattern, forming a conductor on the magnetic film pattern through an insulating film, and forming an upper magnetic layer of permalloy film on the conductor through an insulating film.
Claim 13
Dependent Claim
55 words
The process according to claim 8 or 9, wherein a photoresist of positive type is used as a masking material, the etching solution contains 6-24 g of FeCl 3 , 10-45 cc of HCl, and 15-110 cc of H 3 PO 4 , and the etching solution is kept at a temperature of 30°-70° C.
Claim 14
Dependent Claim
59 words
The process according to claim 8 or 9, wherein a photoresist of positive type is used as a masking material, the etching solution contains 10-40 g of FeCl 3 .6H 2 O, 30-130 cc of 35% HCl, and 20-130 cc of 85% H 3 PO 4 , and the etching solution is kept at a temperature of 30°-70° C.
Claim 15
Dependent Claim
55 words
The process according to claim 8 or 9, wherein a photoresist of negative type is used as a masking material, the etching solution contains not more than 48 g of FeCl 3 , 10-45 cc of HCl and 15-110 cc of H 3 PO 4 , and the etching solution is kept at 10°-90° C.
Claim 16
Dependent Claim
62 words
The process according to claim 8 or 9, wherein a photoresist of negative type is used as a masking material, the etching solution contains not more than 80 g of FeCl 3 .6H 2 O, 30-130 cc of 35% HCl, and 20-130 cc of 85% H 3 PO 4 , and the etching solution is kept at a temperature of 10°-90° C.
Claim 17
Dependent Claim
35 words
The process according to claim 1, 8 or 9, wherein said etching the side edges of the permalloy film into a gradually reduced state of film thickness reduces the side edges into a tapered state.
References Cited (Backward Citations)
US3677843A
Cited
JPS4941243A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-17 | 1987-10-17 | 1988-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-17 | 1991-10-17 | 1992-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-17 | 1995-10-17 | 1996-04-17 | $7700.00 | Window Closed / Lapsed |