| 摘要 |
PROBLEM TO BE SOLVED: To provide a plasma etching method which is capable of increasing an etching rate selection ratio between an oxide film as a lower layer and a tungsten film or a tungsten silicide film. SOLUTION: As a work, an oxide film 2 is formed on a silicon substrate 1, and a tungsten film 3 as an etching target material is formed on the oxide film 2. When the tungsten film 3 is subjected to etching using a photoresist film 4 covering the tungsten film 3 as a mask, a mixed gas of SF6 and SiF4 as fluorine gas series, O2, Cl2, and N2 is used as etching gas. The above fluorine series and chlorine series etching seeds etch both the tungsten film 3 and the oxide film 2. The reaction products produced by the chlorine series etching seeds have a higher vapor pressure than the reaction products produced by the fluorine series etching seeds, so that the etching rate of chlorine series etching seeds is slow, the reaction products of the fluorine series etching seeds are attached to the oxide film 2 and the tungsten film 3 and conducive to an improvement in shape controllability. COPYRIGHT: (C)2004,JPO&NCIPI
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