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Patent EP0168763A2 successfully refreshed from Google Patents.
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EP0168763A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Method for fabricating a master recording disc

Assignee: Victor Company of Japan Ltd
•
Filing: 1985-07-10
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Granted: —
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Expires: 2005-07-10
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Abstract

Abstract In a method of fabricating a master recording disc, a photoresist layer is formed on a glass substrate to form a master blank, which is revolved and exposed to an intensity-modulated laser beam so that a series of optically excited regions is formed in track turns in the photoresist layer. The optically excited regions are removed, forming a series of pits in the photoresist layer. An etchant gas is sputtered onto the master blank until the pits in the photoresist layer extend through the boundary surface of the photoresist layer and the glass substrate to a desired depth and pits having side walls tapered in a direction away from the boundary surface are formed in the substrate. The photoresist layer which remains on the glass substrate is finally removed.

Inventors

  • 👤 Noboru Kawai
  • 👤 Toshiro Abe
  • 👤 Kei Murata

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-31 02:51
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/0057; G11B23/0064; G11B23/0085; G11B7/00; G11B7/24; G11B7/26; G11B7/261; Y; Y10; Y10S; Y10S430/00; Y10S430/146

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 194 words
A method for fabricating a master recording disc using a master blank (12) comprising a glass substrate (10) and a photoresist layer (11), wherein the master blank is revolved and the photoresist layer is exposed to a laser beam which is modulated in intensity with a signal to be reproduced so that a series of optically excited regions is formed in track turns in said photoresist layer and said optically excited regions are removed to form a series of pits (13) in said photoresist layer, and wherein an etchant gas is used in an etching process to increase the depth of said pits (13), and the photoresist layer is removed after the etching process, characterized in that said photoresist layer (11) is directly deposited on said glass substrate (10) and in that said master blank is sputtered with said etchant gas until the pits (13) in said photoresist layer extend through and beyond the boundary surface of the photoresist layer (11) and the glass substrate (10) to a desired depth from said boundary surface and pits (14) having side walls tapered in a direction away from said boundary surface are formed in said substrate.
Claim 2
Independent Claim 194 words
A method for fabricating a master recording disc using a master blank (12) comprising a glass substrate (10) and a photoresist layer (11), wherein the master blank is revolved and the photoresist layer is exposed to a laser beam which is modulated in intensity with a signal to be reproduced so that a series of optically excited regions is formed in track turns in said photoresist layer and said optically excited regions are removed to form a series of pits (13) in said photoresist layer, and wherein an etchant gas is used in an etching process to increase the depth of said pits (13), and the photoresist layer is removed after the etching process, characterized in that said photoresist layer (11) is directly deposited on said glass substrate (10) and in that said master blank is sputtered with said etchant gas until the pits (13) in said photoresist layer extend through and beyond the boundary surface of the photoresist layer (11) and the glass substrate (10) to a desired depth from said boundary surface and pits (14) having side walls tapered in a direction away from said boundary surface are formed in said substrate.
Claim 3
Dependent Claim 39 words
A method as claimed in claim 1, characterized in that said glass substrate is composed of 90 or less weight percent of Si0 2 and 10 or more weight percent of a composition which is inactive to said etchant.
Claim 4
Dependent Claim 18 words
A method as claimed in claim 1 or 2, characterized in that said etchant is CF 4 .
Claim 5
Dependent Claim 21 words
A method as claimed in claim 3, characterized in that said photoresist layer has a thickness of about 4000 angstrom units.

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