US4724043A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for forming a master mold for optical storage disks
Assignee: International Business Machines Corp
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Filing: 1986-12-24
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Granted: 1988-02-09
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Expires: 2006-12-24
Abstract
Abstract A method for forming a master mold for optical storage disks includes thermally growing an oxide or nitride layer on a semiconductor wafer. The thermally grown layer is then coated with a photoresist. The photoresist is exposed to a laser beam to form a data pattern and developed. The oxide or nitride under the developed pattern is etched and the photoresist stripped to provide a semiconductor master mold for optical disks.
Inventors
- 👤 Albert S. Bergendahl
- 👤 Paul E. Cade
- 👤 Norman T. Gonnella
- 👤 Francis S. Luecke
- 👤 Kurt E. Petersen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:09
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/0057; G11B7/00; G11B7/24; G11B7/26; G11B7/261
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
173 words
A process for forming a master mold for insertion in a molding jig used for making optical storage disks having data pits of a predetermined depth, the steps including: thermally creating a layer of etchable material on a surface of a single-crystalline semiconductor substrate, said substrate and said etchable layer forming a monolithic structure with the thickness of said etchable layer corresponding to the predetermined depth of data pits to be molded in an optical storage disk, applying a photoresist layer on said layer of etchable material, exposing said photoresist layer to generate a data pattern in the photoresist layer, developing and removing portions of the exposed photoresist to produce a data pattern mask, etching said layer of etchable material, through said mask, down to the semiconductor substrate effectively forming pits in the monolithic structure, said pits having a depth corresponding to the predetermined depth of data pits to be molded in an optical disk, and removing the remaining photoresist to form a master mold for insertion in the optical disk molding jig.
Claim 2
Dependent Claim
173 words
A process for forming a master mold for insertion in a molding jig used for making optical storage disks having data pits of a predetermined depth, the steps including: thermally creating a layer of etchable material on a surface of a single-crystalline semiconductor substrate, said substrate and said etchable layer forming a monolithic structure with the thickness of said etchable layer corresponding to the predetermined depth of data pits to be molded in an optical storage disk, applying a photoresist layer on said layer of etchable material, exposing said photoresist layer to generate a data pattern in the photoresist layer, developing and removing portions of the exposed photoresist to produce a data pattern mask, etching said layer of etchable material, through said mask, down to the semiconductor substrate effectively forming pits in the monolithic structure, said pits having a depth corresponding to the predetermined depth of data pits to be molded in an optical disk, and removing the remaining photoresist to form a master mold for insertion in the optical disk molding jig.
Claim 3
Dependent Claim
21 words
A process according to claim 1 wherein said single crystalline semiconductor substrate is selected from a group including silicon and germanium.
Claim 4
Dependent Claim
28 words
A process according to claim 1 wherein said semiconductor substrate is silicon and said layer of etchable material is silicon oxide and is thermally grown on said substrate.
Claim 5
Dependent Claim
18 words
A process according to claim 1 wherein the photoresist layer in said applying step is a positive photoresist.
Claim 6
Dependent Claim
15 words
A process according to claim 1 wherein said applying step is accomplished by spin coating.
Claim 7
Dependent Claim
24 words
A process according to claim 1 wherein the photoresist layer is exposed to a laser beam modulated according to the data to be stored.
Claim 8
Dependent Claim
32 words
A process according to claim 4 wherein the exposed photoresist is developed using a method allowing removal to occur at the portions of the photoresist layer not exposed to the laser beam.
Claim 9
Dependent Claim
17 words
A process according to claim 5 wherein said thermally created layer is etched by reactive ion etching.
Claim 10
Dependent Claim
16 words
A process according to claim 5 wherein said thermally created layer is etched by sputter etching.
Claim 11
Dependent Claim
17 words
A process according to claim 5 wherein said thermally created layer is etched by aqueous chemical etching.
Claim 12
Dependent Claim
36 words
A process according to claim 1 wherein said semiconductor substrate is silicon and said layer of etchable material is selected from a group including silicon oxide and silicon nitride and is chemical-vapor deposited on said substrate.
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) | 1991-02-08 | 1991-08-10 | 1992-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-08 | 1995-08-10 | 1996-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-08 | 1999-08-10 | 2000-02-09 | $7700.00 | Window Closed / Lapsed |