| abstract |
Provided is a miniaturized and high-density semiconductor device. A semiconductor device includes: a first layer; a second layer on the first layer; a third layer on the second layer; and a fourth layer on the third layer, wherein the first layer has a first transistor, the first The second layer has a first insulating film and a first conductive film. The first conductive film has a function of electrically connecting the first transistor and the second transistor through an opening provided in the first insulating film, and the third layer has a Two insulating films and a second conductive film, the second conductive film has a function of electrically connecting the first transistor, the second transistor and the first conductive film through an opening provided in the second insulating film, and the fourth layer has The second transistor, the channel formation region of the first transistor has a single crystal semiconductor, the channel formation region of the second transistor has an oxide semiconductor, and the width of the bottom surface of the second conductive film is 5 nm or less. |