| 摘要 |
PURPOSE: A method for controlling the etching selectivity between a doped oxide layer and an undoped oxide layer is provided to be capable of reducing the etching selectivity by minimizing the adsorbed moisture of the doped oxide layer before carrying out an etching process. CONSTITUTION: An oxide layer is formed on the upper portion of a wafer. The moisture existing on the surface of the oxide layer, is removed by flowing high temperature N2 gas to the wafer during the stabilizing step. Then, an etching process is carried out by using HF gas and vapor of deionized water. Preferably, the N2 gas is flowed at the temperature of 100-350 °C. Preferably, the stabilizing step is carried out for 5-10 minutes.
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