Semiconductor device and method for manufacturing semiconductor device

A method for manufacturing a semiconductor device, the method comprising:

• 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,
• processing the second conductive layer to form a first opening portion comprising a region overlapping with the first conductive layer,
• processing the first insulating layer to form a second opening portion that comprises a region overlapping with the first opening portion and reaches the first conductive layer,
• forming a conductive film covering the first opening portion and the second opening portion,
• performing anisotropic etching on the conductive film to form a third conductive layer that comprises a region in contact with the first conductive layer and has an uppermost portion positioned below an end portion of a bottom surface of the second conductive layer on the first opening portion side,
• forming an insulating film covering the second conductive layer and the third conductive layer,
• performing anisotropic etching on the insulating film until at least part of a top surface of the second conductive layer is exposed to form a second insulating layer covering the third conductive layer,
• forming a semiconductor layer comprising a region in contact with the first conductive layer and a region in contact with the second conductive layer,
• forming a third insulating layer comprising a region positioned in the second opening portion, and
• forming, over the third insulating layer, a fourth conductive layer comprising a region positioned in the second opening portion.

A method for manufacturing a semiconductor device, the method comprising:

• forming a first conductive layer,
• forming a first insulating layer over the first conductive layer,
• processing the first insulating layer to form a first opening portion reaching the first conductive layer,
• forming a conductive film covering the first opening portion,
• performing anisotropic etching on the conductive film to form a second conductive layer that comprises a region in contact with the first conductive layer and has an uppermost portion positioned below an end portion of a top surface of the first insulating layer on the first opening portion side,
• forming a second insulating layer covering the first conductive layer, the second conductive layer, and the first insulating layer,
• forming, over the second insulating layer, a third conductive layer comprising a second opening portion comprising a region overlapping with the first opening portion,
• forming, in the second insulating layer, a third opening portion reaching the first conductive layer in the first opening portion,
• forming a semiconductor layer comprising a region in contact with the first conductive layer and a region in contact with the third conductive layer,
• forming a third insulating layer comprising a region positioned in the first opening portion, and
• forming, over the third insulating layer, a fourth conductive layer comprising a region positioned in the first opening portion.