# US 4,394,438 A · Method of manufacturing an optically readable information carrier using deep U.V. radiation

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- Number: US 4,394,438 A
- Document ID: US4394438A
- Status: Granted
- Kind: A
- Application number: 06/291,703
- Filed: 1981-08-10
- Granted: 1983-07-19
- Earliest claimed: 1980-12-22
- Assignees: U.S. Philips Corporation
- Inventors: Pieter Van Pelt; Gerardus J. M. Lippits
- Web page: https://patentgrep.com/patent/US4394438A

## CPC

- G11B 7/261: {Preparing a master, e.g. exposing photoresist, electroforming}
- G03F 7/0005: {Production of optical devices or components in so far as characterised by the lithographic processes or materials used therefor}
- G03F 7/039: Macromolecular compounds which are photodegradable, e.g. positive electron resists (G03F7/075 takes precedence; macromolecular quinonediazides G03F7/023)
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)

## Abstract

A method of manufacturing an optically readable information carrier in which a substrate 1 which is provided on at least one surface with a material which is sensitive to deep ultraviolet light having a wavelength from 190-300 nm, is exposed to deep ultraviolet light via a contact mask 2 which on one side has a layer 4 of a material which is not permeable to deep ultraviolet light in which an information track 5, 6 has been provided, after which the exposed plate is developed and if desired is provided with a reflection layer.

## Claims

### Claim 1

A method of manufacturing an optically readable information carrier in which a substrate plate is provided on one side or on both sides with an optical structure which structure comprises an information track of information areas situated alternatively at a higher and a lower level, characterized in that a substrate plate which is manufactured entirely from polymethylmethacrylate is exposed, according to a lithographic process, to deep ultraviolet light through a mask which is brought into contact with a surface of said substrate plate, said mask comprising a supporting plate which is transparent to deep ultraviolet light, said supporting plate being provided on the side facing the substrate with a layer of material impermeable to deep ultraviolet light, in which layer a pattern is provided corresponding to the optical structure to be provided in the substrate plate and the substrate plate thus exposed through said mask is then treated with a developer capable of disolving the exposed parts of said polymethylmethacrylate thereby dissolving the exposed parts of said polymethylmethylacrylate and forming an information track on said substrate plate.

### Claim 2 (depends on 1)

A method as claimed in claim 1, characterized in that a mask is used which comprises a supporting plate manufactured from quartz which is provided on one side with a layer of metal or metal oxide in which the pattern has been etched.

### Claim 3 (depends on 1)

A method as claimed in claim 1, characterized in that a mask is provided on one or both surfaces of a substrate plate manufactured from polymethylmethacrylate, said mask comprising a supporting plate of quartz and a layer of metal or metal-oxide provided on the side of the substrate plate in which layer a pattern has been etched, the substrate plate is exposed via the mask for 1-15 minutes to deep ultraviolet light having a wavelength from 200-240 nm originating from a gas discharge lamp having a metal vapour plasma and a light intensity from 150-1500 mJ/cm.sup.2 on the substrate plate, the mask is removed and the exposed substrate plate is treated for at most a few minutes with a developer which comprises a mixture of methylisobutylketone and isopropanol or a mixture of isopropanol and water.