Patent ID: 7727412

Claim:
A dry etching method comprising: a starting structure preparing step of preparing a starting structure including a layer to be processed, an intermediate layer, a first mask layer and a second mask layer, these layers being arranged in this order; a second mask layer processing step of processing the second mask layer in a predetermined pattern; a first mask layer processing step of removing the first mask layer on a bottom of a groove of the pattern by dry etching while particles removed and scattered from the first mask layer adhere to a side face of the second mask layer; an intermediate layer processing step of removing the intermediate layer on a bottom of the groove of the pattern by dry etching and forming a step portion along a peripheral portion of the intermediate layer corresponding to an outline of the pattern following the particles adhering to the side face of the second mask layer, the step portion projecting toward an opposite side to the layer to be processed; a layer-to-be-processed processing step of removing the layer to be processed on a bottom of the groove by dry etching to process the layer to be processed in the pattern; and an intermediate layer removal step of removing substantially completely the intermediate layer on the layer to be processed after the layer-to-be-processed processing step, wherein the first mask layer does not remain on the intermediate layer at the end of the layer-to-be-processed processing step.