Method for forming micro contacts of semiconductor device

Claim 1

A method for forming micro contacts of a semiconductor device, comprising the steps of: forming a gate oxide film on a semiconductor substrate; forming a polysilicon film for a gate electrode over the gate oxide film; forming a first insulating film over the resulting structure obtained after the formation of the polysilicon film; sequentially etching the first insulating film, the polysilicon film and the gate oxide film using a gate electrode mask, thereby forming a gate electrode and a pattern of the gate oxide film while partially exposing the semiconductor substrate; implanting low concentration impurity ions in the exposed portion of the semiconductor substrate under a condition that the first insulating film is used as a mask; forming insulating film spacers on side walls of the first insulating film and gate electrode; implanting high concentration impurity ions in the exposed portion of the semiconductor substrate under a condition that the upper structure disposed on the semiconductor substrate is used as a mask, thereby forming a source/drain region; forming a pad conductive layer to a desired thickness over the resulting structure obtained after the formation of the source/drain region; forming a second insulating film over the pad conductive layer, thereby planarizing the structure; forming a photoresist film pattern on the second insulating film using a contact mask; etching the second insulating film using the photoresist film pattern as a mask such that the pad conductive layer is partially exposed; removing the photoresist film pattern; selectively growing the exposed portion of the pad conductive layer, thereby forming a second conductive layer; etching the second insulating film using the second conductive layer as a mask, thereby forming a pattern of the second insulating film; etching both the pad conductive layer and the second conductive layer; forming a third insulating film over the resulting structure obtained after the etching of the second conductive layer, thereby planarizing the structure; fully etching the structure planarized by the third insulating film until the second insulating film pattern is exposed, and then planarizing the resulting structure; forming a third conductive layer for a bit line to a desired thickness over the planarized structure; and etching the third conductive layer using a bit line mask, thereby forming a bit line which is in contact with the semiconductor substrate.

Claim 2

A method for forming micro contacts of a semiconductor device, comprising the steps of: forming a gate oxide film on a semiconductor substrate; forming a polysilicon film for a gate electrode over the gate oxide film; forming a first insulating film over the resulting structure obtained after the formation of the polysilicon film; sequentially etching the first insulating film, the polysilicon film and the gate oxide film using a gate electrode mask, thereby forming a gate electrode and a pattern of the gate oxide film while partially exposing the semiconductor substrate; implanting low concentration impurity ions in the exposed portion of the semiconductor substrate under a condition that the first insulating film is used as a mask; forming insulating film spacers on side walls of the first insulating film and gate electrode; implanting high concentration impurity ions in the exposed portion of the semiconductor substrate under a condition that the upper structure disposed on the semiconductor substrate is used as a mask, thereby forming a source/drain region; forming a pad conductive layer to a desired thickness over the resulting structure obtained after the formation of the source/drain region; forming a second insulating film over the pad conductive layer, thereby planarizing the structure; forming a photoresist film pattern on the second insulating film using a contact mask; etching the second insulating film using the photoresist film pattern as a mask such that the pad conductive layer is partially exposed; removing the photoresist film pattern; selectively growing the exposed portion of the pad conductive layer, thereby forming a second conductive layer; etching the second insulating film using the second conductive layer as a mask, thereby forming a pattern of the second insulating film; etching both the pad conductive layer and the second conductive layer; forming a third insulating film over the resulting structure obtained after the etching of the second conductive layer, thereby planarizing the structure; fully etching the structure planarized by the third insulating film until the second insulating film pattern is exposed, and then planarizing the resulting structure; forming a third conductive layer for a bit line to a desired thickness over the planarized structure; and etching the third conductive layer using a bit line mask, thereby forming a bit line which is in contact with the semiconductor substrate.