Claims
- 1. A method for etching a chromium film formed on a substrate, comprising the steps of:
- (a) providing a chromium film formed on a substrate,
- (b) forming a coating film having a predetermined pattern on the chromium film, to selectively expose the chromium film, and
- (c) etching the exposed chromium film with an etchant comprising at least 2 mol/l of nitric acid, the concentration of nitric acid in the etchant and the temperature of the etchant being sufficient to cause a decrease in the contact area of the chromium film with the coating film, whereby sidewall surfaces of a remaining pattern of the etched chromium film are tapered.
- 2. The method according to claim 1, wherein the coating film comprises a resist and the concentation of nitric acid in the etchant and the temperature of the etchant are sufficient to strip a portion of the resist from the chromium film while etching the chromium film.
- 3. The method according to claim 2, wherein the resist comprises a phenol novolak resin as a principal chain.
Priority Claims (2)
Number |
Date |
Country |
Kind |
62-245035 |
Sep 1987 |
JPX |
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62-253423 |
Oct 1987 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 07/249,905 filed Sep. 27, 1988, now U.S. Pat. No. 5,007,984.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4725375 |
Fujii et al. |
Feb 1988 |
|
5007984 |
Tsutsumi et al. |
Apr 1991 |
|
Non-Patent Literature Citations (1)
Entry |
Janus, "Chemical Etch Rate Studies on Sputtered Chromium Films", J. Electrochem. Soc., vol. 119, No. 3, Mar. 1972, pp. 392-396. |
Continuations (1)
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Number |
Date |
Country |
Parent |
249905 |
Sep 1988 |
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