Patent ID: 9455337
Filing Date: 2016-09-27
CPC Classification: H01L

Claim Text:
1. A method for manufacturing a semiconductor device, comprising the steps of: forming a first conductive layer; forming a first insulating layer over the first conductive layer; forming a second conductive layer over the first insulating layer using the same material as the first conductive layer; forming a third conductive layer over the second conductive layer; forming a second insulating layer over the third conductive layer; forming a resist mask over the second insulating layer; forming a first opening by etching the second insulating layer using the resist mask as a mask; forming a second opening by processing the first opening and etching the third conductive layer using the second insulating layer as a mask; forming a third opening by processing the second opening and etching the second conductive layer using the third conductive layer as a mask; forming a fourth opening by processing the third opening and etching the first insulating layer using the third conductive layer and the second conductive layer as a mask; forming a fifth opening by processing the fourth opening and etching the first conductive layer using the third conductive layer and the second conductive layer as a mask; forming a sixth opening by processing the fifth opening and etching the first insulating layer using the third conductive layer, the second conductive layer, and the first conductive layer as a mask; and forming a contact plug in the sixth opening.