Active solid-state devices (e.g. – transistors – solid-state diode – Field effect device – Having insulated electrode
Reexamination Certificate
1997-07-14
2003-08-19
Cao, Phat X. (Department: 2814)
Active solid-state devices (e.g., transistors, solid-state diode
Field effect device
Having insulated electrode
C257S413000, C257S388000, C257S410000
Reexamination Certificate
active
06608356
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device and a manufacturing method therefor, and more particularly to structures of a gate electrode and a bit contact of a highly integrated DRAM and a manufacturing method therefor.
A conventional method of manufacturing a MOS transistor having a conventional metal gate electrode will now be described with reference to FIG.
1
.
As shown in
FIG. 1A
, a gate insulation film
212
is formed on a P-type silicon semiconductor substrate
211
, and then a polysilicon film
213
, a barrier metal
214
for preventing reactions between polysilicon and a tungsten film and a tungsten film
215
are deposited. Then, a known lithography method and RIE (Reactive Ion Etching) method are employed to pattern gate electrodes. Then, gate electrodes are used as mask for ion implantation for implanting N-type impurities so that a source/drain diffusion regions
216
are formed in the semiconductor substrate
211
.
Then, a silicon nitride film
217
is deposited on the overall surface, as shown in FIG.
1
B. Then, etching back is performed by the RIE method so that side wall spacers of the silicon nitride film
217
are formed on the side walls of the gate electrodes.
The above-mentioned conventional manufacturing method cannot form a contact hole of a type which approaches gate electrodes in a self alignment manner. That is, the contact hole can be formed when an insulation film
218
is formed on the overall surface, and then a contact hole
219
is formed in the insulation film
218
by using a mask (not shown), as shown in FIG.
1
C. What is worse, the tungsten film is exposed to a portion of the gate electrode after the gate electrodes have been formed (see FIG.
1
B). As a result, there arises a problem in that the side walls of the gates cannot be oxidized and thus RIE damages or ion implantation damages cannot be restored. When the silicon nitride films
217
serving as the side wall spacers have been formed, the quality of the silicon nitride films deposited on the metal deteriorates as compared with the silicon nitride film deposited on the insulation film or polysilicon. Therefore, there arises a problem in that side walls having a satisfactory quality cannot be formed.
BRIEF SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a semiconductor apparatus capable of forming a contact hole adjacent to a gate electrode in a self alignment manner and a manufacturing method therefor.
According to one aspect of the present invention, there is provided a method of manufacturing a semiconductor device comprising a step of forming a gate insulation film on a semiconductor substrate; a step of forming, on the gate insulation film, a gate electrode formed by a first conductive film; a step of forming, on the semiconductor substrate, source/drain diffusion layers; a step of forming, on a side wall of the gate electrode, a spacer formed by a first insulation film; a step of forming a second insulation film on the overall surface and etching back the second insulation film to the same height as that of the gate electrode so that the surface is flattened; a step of etching the gate electrode in the direction of the depth thereof to have a predetermined thickness so as to form a first stepped portion from the first insulation film; a step of filling up the first stepped portion by a second conductive film; a step of etching the second conductive film in the direction of the depth thereof to have a predetermined thickness so as to form a second stepped portion from the first insulation film; and a step of filling up the second stepped portion by a third insulation film.
According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device comprising a step of forming a gate insulation film on a semiconductor substrate; a step of forming, on the gate insulation film, a gate electrode formed by a first conductive film; a step of forming, on the semiconductor substrate, source/drain diffusion layers; a step of forming, on a side wall of the gate electrode, a spacer formed by a first insulation film; a step of forming a second insulation film on the overall surface and etching back the second insulation film to the same height as that of the gate electrode so that the surface is flattened; a step of etching the gate electrode in the direction of the depth thereof to have a predetermined thickness so as to form a first stepped portion from the first insulation film; a step of filling up the first stepped portion by a second conductive film; a step of etching the second conductive film in the direction of the depth thereof to have a predetermined thickness so as to form a second stepped portion from the first insulation film; a step of filling up the second stepped portion by a third insulation film; and a step of etching the second insulation film by a selective etching method using the third insulation film as a mask so as to form a contact hole adjacent to the gate electrode.
According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device comprising a step of forming a gate insulation film on a semiconductor substrate; a step of forming a first conductive film on the gate insulation film; a step of forming a dummy film on the first conductive film; a step of patterning the dummy film and the first conductive film to form a gate electrode; a step of forming, on the semiconductor substrate, source/drain diffusion layers; a step of forming, on the side wall of the dummy film and the first conductive film, a spacer formed by the first insulation film; a step of forming a second insulation film on the overall surface and etching back the second insulation film to the same height as that of the gate electrode so that the surface is flattened; a step of etching the dummy film to form a first stepped portion from the first insulation film; a step of filling up the first stepped portion by the second conductive film; a step of etching the second conductive film in a direction of the depth thereof to have a predetermined thickness so as to form a second stepped portion from the first insulation film; and a step of filling up the second stepped portion by a third insulation film.
According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device comprising a step of forming a gate insulation film on a semiconductor substrate; a step of forming a first conductive film on the gate insulation film; a step of forming a dummy film on the first conductive film; a step of patterning the dummy film and the first conductive film to form a gate electrode; a step of forming, on the semiconductor substrate, source/drain diffusion layers; a step of forming, on a side wall of the dummy film and the first conductive film, a spacer formed by the first insulation film; a step of forming a second insulation film on the overall surface and etching back the second insulation film to the same height as that of the gate electrode so that the surface is flattened; a step of etching the dummy film to form a first stepped portion from the first insulation film; a step of filling up the first stepped portion by the second conductive film; a step of etching the second conductive film in a direction of the depth thereof to have a predetermined thickness so as to form a second stepped portion from the first insulation film; a step of filling up the second stepped portion by a third insulation film; and a step of etching the second insulation film by a selective etching method using the third insulation film as a mask so that a contact hole adjacent to the gate electrode is formed.
According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device comprising a step of forming a gate insulation film on a semiconductor substrate; a step of forming, on the gate insulation film, a gate electrode formed by a first conductive film
Hayasaka Nobuo
Kohyama Yusuke
Okumura Katsuya
Banner & Witcoff , Ltd.
Cao Phat X.
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