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US 5,413,672 AGranted
Method of etching sendust and method of pattern-etching sendust and chromium films
AssigneeNGK Insulators, Ltd.
InventorsEigo Hirotsuji, Naoya Fukuda
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AssigneeNGK Insulators, Ltd.
InventorsEigo Hirotsuji, Naoya Fukuda
Estimating the term…
An etching method for etching a sendust film formed on a substrate is disclosed. In this method, a mixture of acid solutions of nitric acid and hydrochloric acid is used as an etching liquid. The etching is desirably effected while the sendust film is directly or indirectly held in electrical connection with a ferrite member, with an area of a portion of the ferrite member which contacts the etching liquid being twice to twelve times a total area of etched portions of the sendust film. Also disclosed is a method for pattern-etching a sendust film, and a chromium base film formed between the sendust film and a substrate, which includes the steps of: (a) etching the sendust film to form a predetermined sendust pattern; and (b) etching the chromium base film to form a chromium pattern which conforms to the predetermined sendust pattern, such that the chromium base film is directly or indirectly held in electrical connection with a chromium bulk.
An etching method for etching a sendust film formed on a substrate, comprising the step of etching the sendust film using a mixture of acid solutions of nitric acid and hydrochloric acid, wherein said mixture is prepared such that a molar ratio of hydrochloric acid to nitric acid is within a range of 1:1 to 1:5.5.
An etching method for pattern-etching a sendust film, and a chromium base film formed between the sendust film and a substrate, comprising the steps of:
An etching method for etching a sendust film formed on a substrate, comprising the steps of:
Dependencies are inferred from the claim text.