| 摘要 |
PROBLEM TO BE SOLVED: To improve the step coverage of upper-layer wiring by forming a narrow deep hole which is controlled to have a tapered cross section through an interlayer insulating film. SOLUTION: At the etching of an interlayer insulating film 2 for forming a contact hole 8, a fixed amount of nitrogen gas is added in addition to fluorocarbon, one or more kinds of gases of the hydrogen substitution products of fluorocarbon, and argon gas as carrier gases. Consequently, the generating rate of a fluorine radical is decreased, and the reaction between tungsten wiring 1 constituting an underlying film and fluorine is accelerated at the etching, and accordingly, a sidewall protective film 4 composed of a fluorine compound is formed on the sidewall of the contact hole 8, resulting in a tapered contact hole 8. Consequently, the reliability of aluminum wiring 5 which is successively formed as upper-layer wiring is improved, because the step coverage of the wiring is improved.
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