Semiconductor device and method for manufacturing the same

摘要

A miniaturized transistor having high electric characteristics is provided with high yield. In a semiconductor device including the transistor, high performance, high reliability, and high productivity are achieved. In a semiconductor device including a transistor in which an oxide semiconductor film, a gate insulating film, and a gate electrode layer on side surfaces of which sidewall insulating layers are provided are stacked in this order, source and drain electrode layers are provided in contact with the oxide semiconductor film and the sidewall insulating layers. In a process for manufacturing the semiconductor device, a conductive film and an interlayer insulating film are stacked to cover the oxide semiconductor film, the sidewall insulating layers, and the gate electrode layer, and the interlayer insulating film and the conductive film over the gate electrode layer are removed by a chemical mechanical polishing method, so that the source and drain electrode layers are formed.

主权项

1. A method for manufacturing a semiconductor device comprising steps of:
forming an oxide insulating film; forming an oxide semiconductor film over the oxide insulating film; forming a gate insulating film over the oxide semiconductor film; forming a gate electrode layer and a first insulating film overlapping with the oxide semiconductor film over the gate insulating film; selectively introducing a dopant into the oxide semiconductor film using the gate electrode layer and the first insulating film as masks; forming a sidewall insulating layer covering a side surface of the gate electrode layer and a side surface of the first insulating film over the gate insulating film; forming a conductive film over the oxide semiconductor film, the gate insulating film, the gate electrode layer, the first insulating film, and the sidewall insulating layer; forming an interlayer insulating film over the conductive film; and removing the interlayer insulating film and the conductive film by a chemical mechanical polishing method to expose the gate electrode layer and form a source electrode layer and a drain electrode layer, and to form a groove between the interlayer insulating film and the sidewall insulating layer, forming a second insulating film so that the second insulating film fills the groove and is in contact with the source electrode layer and the drain electrode layer, wherein a top surface of the source electrode layer and a top surface of the drain electrode layer are lower than a top surface of the sidewall insulating layer and a top surface of the interlayer insulating film, wherein the top surface of the sidewall insulating layer and the top surface of the interlayer insulating film are aligned with each other, wherein an outer surface of each of the source electrode layer and the drain electrode layer is stepped, wherein an inner surface of each of the source electrode layer and the drain electrode layer is in direct contact with the sidewall insulating layer and the oxide semiconductor film, and wherein the outer surface of each of the source electrode layer and the drain electrode layer is opposite to the inner surface of each of the source electrode layer and the drain electrode layer.