Patent ID: 9728422
Date: 2017-08-08
CPC Classifications: H01L

Claim:
1. A dry etching method for a laminated film, the laminated film comprising at least one silicon layer and at least one silicon oxide layer laminated together, the dry etching method comprising: applying a mask with an opening to the laminated film; generating a plasma gas from a dry etching agent; bringing the plasma gas into contact with the laminated film through the opening of the mask; and etching the laminated film with the plasma gas under the application of a bias voltage, thereby forming a through hole in the laminated film in a direction perpendicular to an in-plane direction of the laminated film, wherein the dry etching agent comprises: an unsaturated hydrofluorocarbon represented by the following formula: C iodine heptafluoride, wherein the volume of the iodine heptafluoride in the dry etching agent is 0.1 to 1.0 times the volume of the unsaturated hydrofluorocarbon in the dry etching agent.