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US5242849A
Expired / Lapsed
US
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Method for the fabrication of MOS devices
Assignee: United Microelectronics Corp
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Filing: 1992-05-22
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Granted: 1993-09-07
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Expires: 2012-05-22
Abstract
Abstract After the formation of SiO 2 films that are field oxide films and P + -type diffusion layers that are stopper channels, the Si 3 N 4 films are subjected to an isotropic etching process, thereby removing the regions adjacent to the edges of the SiO 2 films of the Si 3 N 4 films. By using the Si 3 N 4 and SiO 2 films as a mask, N-type impurities are implanted into the Si substrate adjacent to the edges of the SiO 2 films. Then the P + -type diffusion layers disappear adjacent to the edges of the SiO 2 films and the P + -type diffusion layers are isolated from the N + -type diffusion layers, whereby semiconductor devices that are faster and are highly reliable and dependable in operation can be fabricated.
Inventors
- 👤 Yasuo Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:03
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0125; H10W10/0126; H10W10/10; H10W10/13
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
172 words
A method of fabrication of MOS devices characterized by comprising a first step for writing a predetermined pattern of antioxidant film on a semiconductor substrate; a second step for forming, by using said antioxidant film formed in said first step as a mask, field oxide films for electrical isolation of circuit elements on said semiconductor substrate; a third step for forming channel stoppers below said field oxide films formed in said second step; the concentration of impurities of the same conductivity type as said semiconductor substrate in said channel stoppers being higher than that of said semiconductor substrate; a fourth step for removing the edges of said antioxidant film formed in said first step, thereby leaving a portion of said antioxidant film remaining; and a fifth step for diffusing or implanting the impurities of conductivity type opposite that of said impurities in said channel stoppers into said semiconductor substrate by using the remaining portion of said antioxidant film not removed by said fourth step and using said field oxide films as masks.
Claim 2
Independent Claim
172 words
A method of fabrication of MOS devices characterized by comprising a first step for writing a predetermined pattern of antioxidant film on a semiconductor substrate; a second step for forming, by using said antioxidant film formed in said first step as a mask, field oxide films for electrical isolation of circuit elements on said semiconductor substrate; a third step for forming channel stoppers below said field oxide films formed in said second step; the concentration of impurities of the same conductivity type as said semiconductor substrate in said channel stoppers being higher than that of said semiconductor substrate; a fourth step for removing the edges of said antioxidant film formed in said first step, thereby leaving a portion of said antioxidant film remaining; and a fifth step for diffusing or implanting the impurities of conductivity type opposite that of said impurities in said channel stoppers into said semiconductor substrate by using the remaining portion of said antioxidant film not removed by said fourth step and using said field oxide films as masks.
Claim 3
Dependent Claim
59 words
A method for the fabrication of MOS devices as defined in claim 1, characterized in that in said second and third steps of said method, BF 2 is implanted into said semiconductor substrate by using said antioxidant film as a mask and said BF 2 implanted semiconductor substrate is subjected to thermal oxidation, thereby forming said field oxide films.
Claim 4
Dependent Claim
58 words
A method for the fabrication of MOS devices as set forth in claim 1, characterized in that in said second and third steps of said method, by using said antioxidant film as a mask, boron is implanted into said semiconductor substrate and said boron implanted semiconductor substrate is subjected to thermal oxidation, thereby forming said field oxide films.
Claim 5
Dependent Claim
48 words
A method for the fabrication of MOS devices as defined in claim 1, characterized in that said second and third steps of said method includes a step for forming said channel stoppers below said antioxidant film by thermal diffusion simultaneous with the formation of said field oxide films.
Claim 6
Dependent Claim
32 words
A method for the fabrication of MOS devices as defined in claim 1, characterized in that said fourth step for removing the edges of said antioxidant film includes an isotropic etching process.
Claim 7
Dependent Claim
48 words
A method for the fabrication of MOS devices as defined in claim 1, characterized in that said fourth step of said method for removing the edges of said antioxidant film further includes a step for carrying out selective etching of said field oxide films by a photolithographic technique.
Claim 8
Dependent Claim
39 words
A method for the fabrication of MOS devices as defined in claim 1, characterized in that said fourth step of said method includes a step for selectively removing the region of said antioxidant film covering said field oxide films.
Claim 9
Dependent Claim
61 words
A method for the fabrication of MOS devices as defined in claim 1, characterized in that said fifth step of said method includes a step for diffusing or implanting said impurities of opposite conductivity type into said semiconductor substrate to eliminate a part of said channel stoppers adjacent to said field oxide films, thereby isolating the channel stoppers from active regions.
Claim 10
Dependent Claim
34 words
A method for the fabrication of MOS devices as defined in claim 1, characterized in that in said fifth step of said method, phosphorus ions are implanted as said impurities into said semiconductor substrate.
Claim 11
Dependent Claim
34 words
A method for the fabrication of MOS devices as defined in claim 1, characterized in that in said fifth step of said method, arsenic ions are implanted as said impurities into said semiconductor substrate.
Claim 12
Dependent Claim
33 words
A method for the fabrication of MOS devices as defined in claim 1, characterized in that in said first step of said method, said antioxidant film contains a Si 3 N 4 film.
Claim 13
Dependent Claim
43 words
A method for the fabrication of MOS devices as defined in claim 1, characterized in that in said first step of said method, said antioxidant film includes a compound film consisting of a Si 3 N 4 film and a polycrystalline silicon film.
References Cited (Backward Citations)
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