Patent US5453397A successfully refreshed from Google Patents.
US5453397A
Expired / Lapsed
US
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Manufacture of semiconductor device with field oxide
Assignee: Fujitsu VLSI Ltd
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Filing: 1994-09-12
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Granted: 1995-09-26
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Expires: 2014-09-12
Abstract
Abstract A method of manufacturing a semiconductor device capable of isolating fine pattern elements by using LOCOS. The method includes the steps of: (a) forming a relatively thick first nitride film pattern on the surface of a semiconductor substrate having an oxide film; (b) wet-etching the oxide film by using the first nitride film as a mask; (c) filling the under-etch region of the first nitride film with nitride and forming a second nitride film thinner than the first nitride film on the exposed surface of the semiconductor substrate; (d) thermally oxidizing all the exposed second nitride film in a dry oxygen atmosphere to form an oxide film on the surface of the semiconductor substrate at least at the region not covered with tile first nitride film; and (e) forming a thermal oxide film on the semiconductor substrate not covered with the first nitride film at a temperature lower than the oxidation temperature at the step (d).
Inventors
- 👤 Taiji Ema
- 👤 Masaya Katayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:50
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/10; H10W10/13; H10P; H10P14/00; H10P14/60; H10P14/61; H10W10/01; H10W10/011; H10W10/012; H10W10/0125; H10W10/0126
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
231 words
A method of manufacturing a semiconductor device comprising the steps of: (a) forming a first oxide film on the surface of a semiconductor substrate and forming a first patterned nitride film on the surface of said first oxide film; (b) isotropically etching said first oxide film by using said first nitride film as a mask to partially expose the surface of said semiconductor substrate and form a hollow just under the end portion of said first nitride film; (c) forming a second oxide film thinner than said first oxide film at least on the exposed surface of said semiconductor substrate and on the inner surface of said hollow; (d) depositing a nitride film on said semiconductor substrate to form a second nitride film on the surface of said second oxide film at least at the region excepting the inner surface of said hollow and form a nitride region filling the inside of said hollow; (e) thermally oxidizing said second nitride film outside the hollow in a dry atmosphere to convert said second nitride film outside the hollow into a third oxide film combined with said second oxide film; and (f) thermally oxidizing the surface of said semiconductor substrate at the region not covered with the resultant remaining portion of said first nitride film at a temperature lower than the oxidation temperature at the step (e), to form a field oxide film.
Claim 2
Independent Claim
231 words
A method of manufacturing a semiconductor device comprising the steps of: (a) forming a first oxide film on the surface of a semiconductor substrate and forming a first patterned nitride film on the surface of said first oxide film; (b) isotropically etching said first oxide film by using said first nitride film as a mask to partially expose the surface of said semiconductor substrate and form a hollow just under the end portion of said first nitride film; (c) forming a second oxide film thinner than said first oxide film at least on the exposed surface of said semiconductor substrate and on the inner surface of said hollow; (d) depositing a nitride film on said semiconductor substrate to form a second nitride film on the surface of said second oxide film at least at the region excepting the inner surface of said hollow and form a nitride region filling the inside of said hollow; (e) thermally oxidizing said second nitride film outside the hollow in a dry atmosphere to convert said second nitride film outside the hollow into a third oxide film combined with said second oxide film; and (f) thermally oxidizing the surface of said semiconductor substrate at the region not covered with the resultant remaining portion of said first nitride film at a temperature lower than the oxidation temperature at the step (e), to form a field oxide film.
Claim 3
Dependent Claim
20 words
A method according to claim 1, wherein said first oxide film has a thickness of about 15 to 40 nm.
Claim 4
Dependent Claim
19 words
A method according to claim 1, wherein the oxidation temperature at the step (f) is lower than 950° C.
Claim 5
Dependent Claim
18 words
A method according to claim 3, wherein the oxidation temperature at the step (f) is about 900° C.
Claim 6
Dependent Claim
20 words
A method according to claim 1, wherein the oxidation temperature at the step (e) is at least about 1200° C.
Claim 7
Dependent Claim
45 words
A method according to claim 1, further comprising a step of implanting first impurity ions through said first nitride film by using a resist film pattern having an opening over a region of the surface of said semiconductor substrate, between the steps (d) and (e).
Claim 8
Dependent Claim
42 words
A method according to claim 6, wherein the step (e) includes a step of diffusing said first impurity ions into said semiconductor substrate by maintaining said semiconductor substrate at a sufficient temperature for a sufficient time after forming said third oxide film.
Claim 9
Dependent Claim
47 words
A method according to claim 1, further comprising a step of etching and removing said third oxide film and a step of forming a fourth oxide film thinner than said third oxide film on the surface of said exposed semiconductor surface, between the steps (e) and (f).
Claim 10
Dependent Claim
41 words
A method according to claim 8, further comprising a step of implanting impurity ions into a predetermined region by using said first nitride film as a mask after the formation of said fourth oxide film, to form a channel stop layer.
Claim 11
Dependent Claim
20 words
A method according to claim 1, wherein said second oxide film has a thickness of about 5 nm or less.
Claim 12
Dependent Claim
20 words
A method according to claim 10, wherein said first oxide film has a thickness of about 20 to 40 nm.
Claim 13
Dependent Claim
20 words
A method according to claim 10, wherein the oxidation temperature at the step (e) is about 1200° C. or higher.
Claim 14
Dependent Claim
20 words
A method according to claim 12, wherein the oxidation temperature at the step (f) is about 900° C. or lower.
References Cited (Backward Citations)
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