Method for forming field oxide of semiconductor devices

专利摘要:
PURPOSE: A method for forming a field oxide is provided to simplify manufacturing process and prevent a damage of sides of field oxide by forming a spacer using oxidation process. CONSTITUTION: After depositing a pad oxide(15) on a semiconductor substrate(10), a field region(25) is defined by etching the pad oxide(15). A nitride layer(30) is deposited on the field region(25). A trench(35) is formed by etching the field region(25) and the silicon substrate(10). After depositing a trench oxide(43) at sides of the trench, a field oxide(45) is formed by filling and polishing the trench. By removing the remained nitride layer(30), a spaced part(50) is formed. Then, by performing oxidation process, a spacer(55) is formed at the spaced part(50).
公开号:KR20000027813A
申请号:KR1019980045843
申请日:1998-10-29
公开日:2000-05-15
发明作者:임재영
申请人:김영환；현대전자산업 주식회사；
IPC主号:

专利说明:

Field oxide film formation method of semiconductor device
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the formation of field oxide films, and in particular, trenches are formed in semiconductor substrates, field oxide films are formed therein to remove residual nitride films, and spacers are formed by an oxidation process to simplify the process. The present invention relates to a method of forming a field oxide film of a semiconductor device to prevent side surfaces from being damaged to improve leakage current.
In general, in order to form transistors and capacitors on a semiconductor substrate, an isolation region is formed in the semiconductor substrate to prevent electrical conduction with an electrically energized active region and to separate devices from each other. Will form.
As such, in the process for forming the field oxide film formed by growing the pad oxide film to separate the devices, the nitride film is etched by masking the pad oxide film and the nitride film on the semiconductor substrate and the etched device isolation region is formed. There is a LOCOS process (Local Oxidation of silicon) to form a field oxide film in the film, and in addition, a PBL that grows a field oxide film by buffering a polysilicon film acting as a buffer between the pad oxide film and the nitride film of the LOCOS process Poly Buffered LOCOS process is used.
In addition, by forming a trench having a constant depth in the semiconductor substrate, depositing an oxide film on the trench, and etching an unnecessary portion of the oxide film by a chemical mechanical polishing process, an element isolation region is formed on the semiconductor substrate. The Shallow Trench Isolation (STI) process to be formed has been widely used in recent years, and the present invention proposes a new process for forming a field oxide film using the STI process.
1 to 3 are views sequentially showing a state in which a field oxide film is formed by forming a trench in a conventional semiconductor device, and FIG. 1 shows a pad oxide film 2 to be insulated with a predetermined thickness on a semiconductor substrate 1. ), The nitride film 3 acting as a protection between the upper and lower layers is applied thereon, the photosensitive film is coated on the nitride film 3 of the portion where the trench is to be formed, and the trench is exposed. 4) shows a state of forming.
2 shows the trench oxide film 5 by oxidatively growing on the inner wall surface of the trench 4 by wet oxidation at a high temperature in order to prevent leakage current due to concentration of a field effect in the portion where the trench 4 is formed. ) Is shown.
FIG. 3 shows that the field oxide film 6 is formed by removing the unnecessary portion by etching after the capfill oxide film is filled in the trench 4 on the trench oxide film 4 by a cap filling process. The oxide film is deposited on the edge of the field oxide film 6 by chemical vapor deposition, and the spacer 7 is formed by etching.
However, conventionally, the gap filling oxide film is deposited in the trench 5, and then the gap filling oxide film is polished and formed by etching, and the nitride film 3 laminated on the pad oxide film 2 is etched. By removing the field oxide film 7 slightly exposed to the upper surface, at this time, since the damage caused by etching occurs in the side portion of the field oxide film 7, spacers 8 are formed on both side surfaces of the field oxide film 7. However, it is often formed, but the role is often insufficient to increase the leakage current has a problem of lowering the characteristics of the device.
An object of the present invention is to form a field oxide film forming portion on the pad oxide film by masking etching after laminating the pad oxide film on the semiconductor substrate, the nitride film is laminated therein, the trench is formed in the substrate through the nitride film by the etching process, The purpose is to improve the leakage current by forming a field oxide film therein to remove the remaining nitride film and forming a spacer by an oxidation process to simplify the process and prevent damage to the side portions of the field oxide film.
1 to 3 are views sequentially showing a field oxide film forming method of a conventional general semiconductor device,
4 to 12 are views sequentially showing a field oxide film forming method of a semiconductor device according to the present invention.
* Description of the symbols for the main parts of the drawings *
10: semiconductor substrate 15: pad oxide film
20: photosensitive film 25: field oxide film forming site
30: nitride film 35: trench
40: gap peeling oxide film 45: field oxide film
50: space part 55: spacer
The object of the present invention is to form a field oxide film forming region by laminating a pad oxide film on a semiconductor substrate and etching the pad oxide film with a photosensitive film; Removing a photoresist film remaining on the pad oxide film, and then depositing a nitride film on the field oxide film forming portion; Forming a trench by etching the nitride film and the semiconductor substrate to a predetermined depth with a narrower width than the field oxide film forming portion of the pad oxide film; Stacking a trench oxide film on a side surface of the trench and then stacking a gap peeling oxide film in the trench to form a field oxide film by chemical mechanical polishing; It is achieved by providing a method for forming a field oxide film of a semiconductor device comprising removing a nitride film remaining in the side portion of the field oxide film and forming a spacer in an oxide film deposition process in a space formed between the pad oxide film and the side portion of the field oxide film.
The thickness of the pad oxide film is 300 to 500 kPa, the deposition thickness of the nitride film is 800 to 1200 kPa, and the thickness of the trench oxide film is 280 to 320 kPa.
And after laminating the gap peeling oxide film to annealing in an atmosphere of nitrogen gas at a temperature of 1000 ~ 1200 ℃, and when forming a spacer in the space 50 between the pad oxide film and the field oxide film Proceeding to a temperature of 1000 ~ 1200 ℃ to form a thickness of 400 ~ 600Å.
Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.
4 to 12 are views sequentially showing a field oxide film forming method of a semiconductor device according to the present invention.
FIG. 4 shows a state in which the pad oxide film 15 is laminated on the semiconductor substrate 10 with a thickness of 300 to 500 kPa, and then the photosensitive film 20 having the contact portion is stacked on the pad oxide film 15.
FIG. 5 illustrates a state in which the pad oxide film 15 is etched through the contact portion of the photosensitive film 20 to form the field oxide film forming portion 25.
6 and 7 show a state in which the nitride film 30 is laminated on the field oxide film forming portion 25 with a thickness of 800 to 1200 Å after removing the photoresist film 20 remaining on the pad oxide film 15. Doing.
FIG. 8 illustrates a state in which the trench 35 is formed by etching the nitride film 30 and the semiconductor substrate 10 to a predetermined depth with a width narrower than that of the field oxide film forming portion 25 of the pad oxide film 15. Doing.
9 and 10 show a trench oxide film 43 having a thickness of 280 to 320 micrometers on the side surface of the trench 35, and then a gap peeling oxide film 40 is stacked in the trench 35 to form a chemical mechanical polishing method. The state in which the field oxide film 45 is formed by polishing is shown.
At this time, after the lamination of the gap peeling oxide film further comprises the step of annealing in an atmosphere of nitrogen gas at a temperature of 1000 ~ 1200 ℃.
11 illustrates a state in which the space 50 is exposed between the pad oxide film 15 and the side surface of the field oxide film 45 after removing the nitride film 30 remaining on the side surface of the field oxide film 45. have.
FIG. 12 shows a state in which the spacer 55 is formed to a thickness of 400 to 600 kPa at a temperature of 1000 to 1200 占 폚 by an oxide film deposition process in the space 50.
As described above, when the field oxide film forming method for a semiconductor device according to the present invention is used, a pad oxide film is laminated on a semiconductor substrate, and then a field oxide film forming portion is formed on the pad oxide film by masking etching, and a nitrite film is stacked therein. In the etching process, a trench is formed in the substrate through the nitride film, a field oxide film is formed therein, and the spacer is formed in the space formed by removing the nitride film remaining in the side portion of the field oxide film by the oxidation process. It is a very useful and effective invention to improve the leakage current by simplifying and preventing the side surface portion of the field oxide film from being damaged.

权利要求:
Claims (6)
[1" claim-type="Currently amended] Stacking a pad oxide film on a semiconductor substrate and etching the pad oxide film with a photosensitive film to form a field oxide film forming portion;
Removing a photoresist film remaining on the pad oxide film, and then depositing a nitride film on the field oxide film forming portion;
Forming a trench by etching the nitride film and the semiconductor substrate to a predetermined depth with a narrower width than the field oxide film forming portion of the pad oxide film;
Stacking a trench oxide film on a side surface of the trench and then stacking a gap peeling oxide film in the trench to form a field oxide film by chemical mechanical polishing;
Removing the nitride film remaining in the side surface portion of the field oxide film, and forming a spacer by an oxide film deposition process in a space formed between the pad oxide film and the side surface portion of the field oxide film. .
[2" claim-type="Currently amended] The method of forming a field oxide film of a semiconductor device according to claim 1, wherein the deposition thickness of said pad oxide film is 300 to 500 kPa.
[3" claim-type="Currently amended] The method of forming a field oxide film of a semiconductor device according to claim 1, wherein the deposition thickness of said nitride film is 800-1200 GPa.
[4" claim-type="Currently amended] 2. The method of forming a field oxide film of a semiconductor device according to claim 1, wherein the trench oxide film has a thickness of 280 to 320 GPa.
[5" claim-type="Currently amended] The method of claim 1, further comprising annealing in an atmosphere of nitrogen gas at a temperature of 1000 to 1200 ° C. after stacking the gap peeling oxide film.
[6" claim-type="Currently amended] The field of a semiconductor device according to claim 1, wherein when the spacer is formed in the space portion 50 between the pad oxide film and the field oxide film, it is formed at a thickness of 400 to 600 kPa by proceeding at a temperature of 1000 to 1200 占 폚. Oxide film formation method.

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引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

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法律状态:
1998-10-29|Application filed by 김영환, 현대전자산업 주식회사

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1998-10-29|Priority to KR1019980045843A

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2000-05-15|Publication of KR20000027813A

优先权:

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申请号 | 申请日 | 专利标题

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KR1019980045843A|KR20000027813A|1998-10-29|1998-10-29|Method for forming field oxide of semiconductor devices|