METHOD OF CLEANING SILICON SURFACE

摘要

In the first step, a silicon oxide film (21) on a silicon surface (22) is etched away using a CHF3 gas. After the silicon oxide film is removed, organic matter (23) of the CxFy group remains on the silicon surface. In the second step, the organic matter (23) is etched away using a NF3 gas. The silicon oxide film (21) is etched in preference to underlying silicon (22) by using the CHF3 gas. A F radical is easily formed from the NF3 gas used for removing the organic matter (23). At the time of forming this F radical, no residue is formed which makes the silicon surface (22) dirty. Consequently, a clear silicon surface (22) is obtained.