Patent ID: 8679358
Filing Date: 2014-03-25
Classification: H01L

Abstract:
1. A plasma etching method for forming, via a mask layer, a hole in a silicon oxide film under the mask layer using plasma of a processing gas including carbon (C) and fluorine (F), the plasma etching method comprising: a preparation process for performing a plasma etching process using a processing gas including a first processing gas containing carbon (C) and fluorine (F), a ratio (C/F) of carbon (C) to fluorine (F) of the first processing gas having a first value; investigating a relationship between residual amounts of the mask layer and bowing CDs of the hole which is formed at the silicon oxide film; and obtaining, in advance, a residual amount of the mask layer corresponding to a variation point where a variation amount of the bowing CD is increased; a first plasma etching process using the processing gas including the first processing gas until a residual amount of the mask layer reaches the variation point after the preparation process; and a second plasma etching process that is performed after the first plasma etching process, wherein the second plasma etching process is performed by using a processing gas including at least a second processing gas containing carbon (C) and fluorine (F), and a ratio (C/F) of carbon (C) to fluorine (F) of the second processing gas is smaller than the first value.