| abstract |
A semiconductor device that is miniaturized and densified is provided. A semiconductor device comprising: 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 second layer has a first insulating film and a first conductive film, and the first conductive film has a function of electrically connecting the first transistor and the second transistor through an opening portion provided in the first insulating film, and the third layer has a function a second insulating film having a function of electrically connecting the first transistor and the second transistor to the first conductive film by an opening portion provided in the second insulating film, and a second conductive film In 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. |