Renesas Electronics Corporation

Renesas Technology Corp.

Hideyuki Yashima

Yasuhiro Taniguchi

Kazuyoshi Shiba

Shinichiro Abe

Hideaki Yamakoshi

Processing of memory cells forming a nonvolatile memory in a semiconductor device. A second polysilicon film is formed in such a manner as to cover a first polysilicon film and a dummy gate electrode. Thus, the second polysilicon film is formed reflecting the shapes of a step difference portion and a gap groove. Particularly, in the second polysilicon film covering the gap groove, a concave part is formed. Subsequently, over the second polysilicon film, an antireflection film is formed. Thus, the antireflection film having high flowability flows from the higher region to the lower region of the step difference portion, but is stored in a sufficient amount in the concave part. Accordingly, the antireflection film is supplied from the concave part so as to compensate for the amount of the antireflection film to flow out therefrom.

Semiconductor device utilizing dummy gate to enhance processing precision

In a memory cell array on a main surface of a semiconductor substrate, a floating gate electrode for accumulating charges for information is arranged. The floating gate electrode is covered with a cap insulating film and a pattern of an first insulating film formed thereon. Further, over the entire main surface of the semiconductor substrate, an second insulating film is deposited so that it covers the pattern of the first insulating film and a gate electrode. The second insulating film is formed by a silicon nitride film formed by a plasma CVD method. The first insulating film is formed by a silicon nitride film formed by a low-pressure CVD method. By the provision of such an first insulating film, it is possible to suppress or prevent water or hydrogen ions from diffusing to the floating gate electrode, and therefore, the data retention characteristics of a flash memory can be improved.

Semiconductor device and a method of manufacturing the same

In processing memory cells for forming a nonvolatile memory in a semiconductor device, a second polysilicon film is formed in such a manner as to cover a first polysilicon film and a dummy gate electrode. Thus, the second polysilicon film is formed reflecting the shapes of a step difference portion and a gap groove. Particularly, in the second polysilicon film covering the gap groove, a concave part is formed. Subsequently, over the second polysilicon film, an antireflection film is formed. Thus, the antireflection film having high flowability flows from the higher region to the lower region of the step difference portion, but is stored in a sufficient amount in the concave part. Accordingly, the antireflection film is supplied from the concave part so as to compensate for the amount of the antireflection film to flow out therefrom.

Method for manufacturing a semiconductor device including memory cell formation region

In a memory cell array on a main surface of a semiconductor substrate, a floating gate electrode for accumulating charges for information is arranged. The floating gate electrode is covered with a cap insulating film and a pattern of a first insulating film formed thereon. Further, over the entire main surface of the semiconductor substrate, a second insulating film is deposited so that it covers the pattern of the first insulating film and a gate electrode. The second insulating film is formed by a silicon nitride film formed by a plasma CVD method. The first insulating film is formed by a silicon nitride film formed by a low-pressure CVD method. By the provision of such a first insulating film, it is possible to suppress or prevent water or hydrogen ions from diffusing to the floating gate electrode, and therefore, the data retention characteristics of a flash memory can be improved.

Growing community of inventors

Tokyo, Japan

Hideyuki Yashima