Semiconductor device and manufacturing method thereof

A semiconductor device comprising a first transistor, a second transistor, and a capacitor, the semiconductor device comprising:

• a first insulating film over a substrate;
• a first semiconductor layer including silicon over the first insulating film;
• a second insulating film over the first semiconductor layer;
• a first conductive layer over the second insulating film;
• a third insulating film over the first conductive layer;
• a second semiconductor layer including an oxide semiconductor over the third insulating film;
• a fourth insulating film over the second semiconductor layer;
• a second conductive layer over the fourth insulating film;
• a fifth insulating film over the second conductive layer;
• and
• a third conductive layer below the second semiconductor layer,
• wherein the first conductive layer is configured to be a gate electrode of the first transistor,
• wherein the second conductive layer is configured to be a first gate electrode of the second transistor,
• wherein the third conductive layer is configured to be a second gate electrode of the second transistor,
• wherein the first semiconductor layer is in electrical contact with the second semiconductor layer through a fourth conductive layer,
• wherein the fourth conductive layer is in contact with one of a source and a drain of the second semiconductor layer,
• wherein the fourth conductive layer has a region provided in an opening provided in the fifth insulating film,
• wherein a fifth conductive layer is in contact with the other of the source and the drain of the second semiconductor layer,
• wherein the fifth conductive layer is configured to be one electrode of the capacitor, and
• wherein the second semiconductor layer overlaps the first semiconductor layer in a region where the first conductive layer and the third conductive layer do not overlap each other.