Claims
- 1. A method of producing a molding die for an information recording medium, having a mold surface with a prescribed unevenness pattern comprising a projection; said projection having different etching velocities along its projected thickness; said projection defining a pair of convergent opposite inclining side slopes, each slope of said pair forming an acute inclining angle with respect to an extension of said mold surface; said method comprising the steps of:
- forming a pattern-forming layer on a substrate, said pattern-forming layer comprising a common metal element throughout the thickness of the pattern-forming layer and an additional element differing in composition from the common metal element in the thickness direction of the pattern-forming layer, the pattern-forming layer having an etching velocity which is variable in the thickness direction of the pattern-forming layer by varying a proportion of the common metal element with respect to the additional element; and
- etching the pattern-forming layer with an etchant having an unchanging composition to remove the pattern-forming layer selectively and to form said projection.
- 2. A method of producing a molding die for an information recording medium, having a mold surface with a prescribed unevenness pattern comprising a projection; said projection defining a pair of convergent opposite inclining side slopes, each slope of said pair forming an acute inclining angle with respect to an extension of said mold surface; said method comprising the steps of:
- forming on a substrate a pattern-forming layer having a substantially uniform etching velocity in the thickness direction of the pattern-forming layer; and
- etching the pattern-forming layer according to a reactive ion etching process using an etchant gas while changing the etchant gas composition to remove the pattern-forming layer selectively and to form said projection.
- 3. A method according to claim 1, wherein said forming step is performed by sputtering by use of a target with an atmosphere around it, while changing said atmosphere around the target.
- 4. A method according to claim 1, wherein said forming step is performed by sputtering by use of a Cr target with an atmosphere around it, while changing said atmosphere around the target from N.sub.2 and O.sub.2 to N.sub.2.
- 5. A method according to claim 2, wherein said etching step is performed using an etchant gas containing a mixture of CCl.sub.4 and Ar, while changing the ratio of CCl.sub.4 to Ar in said mixture.
Priority Claims (2)
Number |
Date |
Country |
Kind |
62-329680 |
Dec 1987 |
JPX |
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63-103797 |
Apr 1988 |
JPX |
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Parent Case Info
This application is a division of application Ser. No. 07/811,900, filed Dec. 20, 1991, now U.S. Pat. No. 5,234,633, issued Aug. 10, 1992, which in turn is a continuation of application Ser. No. 07/718,906, filed Jun. 24, 1991, now abandoned, which in turn is a continuation of application Ser. No. 07/657,388, filed Feb. 19, 1991, now abandoned, which in turn is a continuation of application Ser. No. 07/290,640, filed Dec. 27, 1988, now abandoned.
US Referenced Citations (18)
Foreign Referenced Citations (6)
Number |
Date |
Country |
0156372 |
Oct 1985 |
EPX |
2028705 |
Oct 1970 |
FRX |
2261860 |
Sep 1975 |
FRX |
1422508 |
Feb 1969 |
DEX |
61-51634 |
Mar 1986 |
JPX |
1-312749 |
Dec 1989 |
JPX |
Non-Patent Literature Citations (4)
Entry |
IBM Technical Disclosure Bulletin, vol. 30, No. 5 (1987), 306:311. |
Patent Abstracts of Japan, vol. 9, No. 111 (M-379) (1985). |
Ahrens, Funkschau, No. 21 (1982), Herstellung einer LV-Bildplatte, 65:68. |
M. Eichlseder, et al., Ind. Prod. Eng., vol. 11, No. 3 (1987), 150:151. |
Divisions (1)
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Number |
Date |
Country |
Parent |
811900 |
Dec 1991 |
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Continuations (3)
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Number |
Date |
Country |
Parent |
718906 |
Jun 1991 |
|
Parent |
657388 |
Feb 1991 |
|
Parent |
290640 |
Dec 1988 |
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