| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for highly selectively etching an underlying silicon oxide film in a semiconductor device, when processing a wiring layer and a silicon substrate at the same time. SOLUTION: When a wiring layer and a silicon substrate are processed at the same time, a flow rate of oxygen in a mixture gas such halogen gases as chlorine gas and an oxygen gas is set at 30-60%, with respect to the total gas low rate. A gas pressure in a reaction chamber 204 is first set at 1×10<-6> torr or lower by a vacuum pump 211, and then a mixture gas containing an O2 gas and a Cl gas in a proportion of 25 sccm of O2 gas and 45 sccm of Cl gas are introduced separately through respective gas inlet pipes 210. Next, a magnetic field is made by an exciting coil, and about 1.75 kW microwave is guided from a microwave oscillator 203 into a plasma generation chamber 201 for generating a plasma of the mixture gas. Further, about 40 W of high-frequency power is applied form a high-frequency power source 208 to an electrode 206 for applying a bias electric field on a semiconductor substrate 207 fixed by an electrostatic attraction thereon for etching the substrate.
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