Etching method and plasma processing apparatus

摘要

A method of etching an etching target layer containing polycrystalline silicon includes preparing a target object including the etching target layer and a mask formed on the etching target layer; and etching the etching target layer with the mask. Further, the mask includes a first mask portion formed of polycrystalline silicon and a second mask portion interposed between the first mask portion and the etching target layer and formed of silicon oxide. Furthermore, in the etching of the etching target layer, a first gas for etching the etching target layer, a second gas for removing a deposit adhering to the mask, and a third gas for protecting the first mask portion are supplied into a processing vessel in which the target object is accommodated, and plasma of these gases is generated within the processing vessel.

主权项

1. A method of etching an etching target layer containing polycrystalline silicon, the method comprising:
preparing a target object including the etching target layer and a mask formed on the etching target layer, the mask including a first mask portion formed of polycrystalline silicon and a second mask portion interposed between the first mask portion and the etching target layer and formed of silicon oxide; supplying a first gas for etching the etching target layer, a second gas for removing a deposit adhering to the mask, and a third gas for protecting the first mask portion into a processing vessel in which the target object is accommodated; generating a plasma of the first, second and third gases within the processing vessel; forming a protective film on an upper surface and a side surface of the first mask portion by reacting O radicals generated by dissociation of the third gas with polycrystalline silicon on the upper and the side surfaces of the first mask portion; and etching the etching target layer with the mask, wherein the first mask portion and the second mask portion are in direct contact with each other, and an upper side of the first mask portion is exposed to the plasma.