EP0166474A1
Expired / Lapsed
EP
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Method of manufacturing a semiconductor device comprising a silicon body, in which a sunken oxide layer is locally provided
Assignee: Koninklijke Philips NV
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Filing: 1985-05-15
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Granted: —
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Expires: 2005-05-15
Abstract
Abstract In this method, after a first oxidation mask (21) has been provided on a surface of the silicon body (1), a depression (40) with side walls (41) extending below the first oxidation mask (21) is formed in the silicon body (1). Subsequently, afterthe side walls (41) have been provided with a second oxidation mask (70), an oxidation treatment is carried out. According to the invention, the depression (40) is provided in a manner such that the side walls (41) areflat and enclose an angle (42) of 25° to 45° with the original surface, while the second oxidation mask (70) is formed by a 5 to 50 nm thick layer (71) of silicon nitride or silicon oxynitride, which is applied directly or separated therefrom by a layer of silicon oxide (72) having a thickness of less than 5 nm to the side walls. The method leads to a very flat structure.
Inventors
- 👤 Jan Gerard Dil
- 👤 Johan Willem Bartsen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 04:26
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6308; H10P14/6309; H10P14/61; H10P14/6322; H10P14/6326; H10P14/6328; H10P14/6334; H10P14/65; H10P14/6502; H10P14/6508; H10P14/6512; H10P14/69; H10P14/692; H10P14/6921; H10P14/6922; H10P14/6927; H10P14/694; H10P14/6943; H10P14/69433; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/0128; H10W10/10; H10W10/13; H10P14/69215
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
175 words
A method of manufacturing a semiconductor device comprising a silicon body, in which a sunken oxide layer is locally provided, in which method, after a first oxidation mask has been locally provided on a surface of the silicon body, a depression with side walls extending at least in part below the first oxidation mask is formed in the silicon body, whereupon the silicon body is subjected to an oxidation treatment after a second oxidation mask adjoining the first oxidation mask has been provided on the side walls of the depression, characterized in that the depression is provided in a manner such that its side walls have a comparatively flat surface which encloses an angle of 25° to 45° with theoriginal surface of the silicon body, and in that the second oxidation mask is formed by a 5 to 50 nm thick layer of silicon nitride or silicon oxynitride which is applied to the side wall of the depression directly or separated therefrom by a silicon oxide layer having a thickness of less than 5 nm.
Claim 2
Independent Claim
175 words
A method of manufacturing a semiconductor device comprising a silicon body, in which a sunken oxide layer is locally provided, in which method, after a first oxidation mask has been locally provided on a surface of the silicon body, a depression with side walls extending at least in part below the first oxidation mask is formed in the silicon body, whereupon the silicon body is subjected to an oxidation treatment after a second oxidation mask adjoining the first oxidation mask has been provided on the side walls of the depression, characterized in that the depression is provided in a manner such that its side walls have a comparatively flat surface which encloses an angle of 25° to 45° with theoriginal surface of the silicon body, and in that the second oxidation mask is formed by a 5 to 50 nm thick layer of silicon nitride or silicon oxynitride which is applied to the side wall of the depression directly or separated therefrom by a silicon oxide layer having a thickness of less than 5 nm.
Claim 3
Dependent Claim
88 words
A method as claimed in Claim 1, characterized in that the depression is formed by subjecting the silicon body, after the first oxidation mask has been provided, to an oxidation treatment and then removing the oxide thus formed, the first oxidation mask being constituted by a 5 to 50 nm thick layer of silicon nitride or silicon oxynitride which is applied to the surface of the silicon body directly or separated therefrom by a layer of silicon oxide having a thickness of less than 5 n M .
Claim 4
Dependent Claim
110 words
A method as claimed in Claim 1 or 2, characterized in that to provide the second oxidation mask after the depression has been formed, the silicon body is, successively covered by a 5 to 50 nm thick layer of silicon nitride or silicon oxynitride and a layer of silicon oxide and in that it then is subjected to an anisotropic etching treatment in which the layer of silicon oxide is removed except below edges of the first oxidation mask projecting above the depression, whereupon exposed silicon nitride or silicon oxynitride is subjected to an etching treatment until the depression has an uncovered bottom, after which remaining silicon oxide is removed.
Claim 5
Dependent Claim
39 words
A method as claimed in Claim 3, characterized in that the first oxidation mask is provided in a thickness of 20 to 50 nm and the second oxidation mask is provided in a thickness of 10 to 20 nm.
Claim 6
Dependent Claim
50 words
A method as claimed in Claim 3 or 4, characterized in that the layer of silicon oxide is etched away anisotropically in a plasma produced in a gas containing CP 3 H and Ar, and the layer of silicon nitride or silicon oxynitride is etched away in hot phosphoric acid.
Claim 7
Independent Claim
68 words
A method as claimed in any one of the preceding Claims, characterized in that the layer of silicon nitride or silicon oxynitride of the first and second oxidation masks is formed by passing over the silicon body at a temperature of 800 to 850°C and a pressure of 10 to 50 Pa, a reaction gas which contains ammonia, dichlorosilane and for the formation of silicon oxynitride laughing gas.
Claim 8
Dependent Claim
32 words
A method as claimed in Claim 6, characterized in that in the reaction gas a volume of laughing gas is included which is at most six times larger than that of ammonia.
Claim 9
Dependent Claim
39 words
A method as claimed in Claim 6 or 7, characterized in that before deposition of the layer of silicon nitride or silicon oxynitride the silicon body is treated in a 60 to 70 % solution of fuming nitric acid.
Claim 10
Dependent Claim
49 words
A method as claimed in Claim 8, characterized in that before deposition of the layer of silicon nitride or silicon oxynitride, but after treatment in nitric acid, the semiconductor body is subjected to a heat treatment at a temperature of 800 to 1200 0 C is an ammonia-containing atmosphere.
Claim 11
Independent Claim
52 words
A method as claimed in any one of the preceding Claims, characterized in that the oxidation treatment is carried out by passing steam over the silicon body at a temperature of 800 to 1100°C and a pressure of 1 to 20 atm. with up to 50 % by volume of oxygen added.
References Cited (Backward Citations)
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