US5084402A
Expired / Lapsed
US
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Method of fabricating a semiconductor substrate, and semiconductor device, having thick oxide films and groove isolation
Assignee: HITACHI IND
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Filing: 1989-05-17
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Granted: 1992-01-28
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Expires: 2009-05-17
Abstract
Abstract A semiconductor device employing a new isolation process is disclosed, wherein an isolation area is a region in which a burying material is buried in a deep groove formed in a semiconductor body with a substantially constant width by anisotropic dry etching, semiconductor elements are formed in selected ones of semiconductor regions isolated by the isolation area, and others of the semiconductor regions, with no semiconductor element formed therein, have their whole surface covered with a thick oxide film which is produced by the local oxidation of the semiconductor body. The new isolation process is well-suited for a bipolar type semiconductor device, wherein the deep groove is formed so as to reach a semiconductor substrate through an N + -type buried layer, and a thick oxide film formed simultaneously with the aforementioned thick oxide film isolates the base region and collector contact region of a bipolar transistor.
Inventors
- 👤 Akihisa Uchida
- 👤 Daisuke Okaka
- 👤 Toshihiko Takakura
- 👤 Katsumi Ogiue
- 👤 Yoichi Tamaki
- 👤 Masao Kawamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:33
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/012; H10W10/041; H10W10/10; H10W10/13; H10W10/17; H10W10/40; Y; Y10; Y10S; Y10S438/00; Y10S438/981
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
104 words
A method of manufacturing a semiconductor substrate, comprising the steps of: (a) selectively forming a thick oxidation film on an inactive region of a main surface of a semiconductor body, said inactive region being a region in which semiconductor elements are not formed, said thick oxidation film being formed by thermal oxidation of said semiconductor body; and (b) after the step (a), forming a groove in said semiconductor body so as to surround active regions of said main surface in which said semiconductor elements are to be formed, said groove being formed in a region of the semiconductor body other than the inactive region.
Claim 2
Independent Claim
104 words
A method of manufacturing a semiconductor substrate, comprising the steps of: (a) selectively forming a thick oxidation film on an inactive region of a main surface of a semiconductor body, said inactive region being a region in which semiconductor elements are not formed, said thick oxidation film being formed by thermal oxidation of said semiconductor body; and (b) after the step (a), forming a groove in said semiconductor body so as to surround active regions of said main surface in which said semiconductor elements are to be formed, said groove being formed in a region of the semiconductor body other than the inactive region.
Claim 3
Dependent Claim
38 words
A method according to claim 1, wherein, after forming said groove, said groove is filled with a material so as to form an isolation structure, whereby the filled groove acts as an isolation structure for a semiconductor device.
Claim 4
Dependent Claim
30 words
A method of manufacturing a semiconductor device, comprising the steps of: (1) forming a semiconductor substrate according to claim 2; and (2) forming said semiconductor elements in said active regions.
Claim 5
Dependent Claim
49 words
A method according to claim 1, wherein said selectively forming a thick oxide film includes selectively providing a patterned oxidation resistant layer on the semiconductor body, and thermally oxidizing said semiconductor body by local thermal oxidation of the semiconductor body using said patterned oxidation resistant layer as a mask.
Claim 6
Dependent Claim
79 words
A method according to claim 1, wherein said semiconductor body includes a first semiconductor region, of a first conductivity type, extending in said first portion of the semiconductor body to a major surface of the semiconductor body, with a semiconductor material, of the first conductivity type, under the first semiconductor region; wherein the thick oxide film is selectively formed on said major surface; and wherein said groove is formed extending from said major surface into said first semiconductor region.
Claim 7
Dependent Claim
98 words
A method according to claim 1, wherein the selectively forming a thick oxide film includes forming a first patterned oxidation resistant layer on a first area of the semiconductor body, forming a second patterned oxidation resistant layer on a second area of the semiconductor body, and locally thermally oxidizing the semiconductor body using the first and second patterned oxidation resistant layers on a mask to form the thick oxide film; and wherein the forming a groove includes removing the second patterned oxidation resistant layer and forming the groove at the location of the second patterned oxidation resistant layer.
Claim 8
Dependent Claim
104 words
A method according to claim 6, wherein the first patterned oxidation resistant layer comprises a first film of oxidation resistant material formed on the semiconductor body and a second film on the first film, and the second patterned oxidation resistant layer includes another film of oxidation resistant material formed on the semiconductor body; and wherein the forming a groove includes removing said another film of oxidation resistant material so as to expose a part of the semiconductor body while leaving at least a portion of said first film of oxidation resistant material, the groove being formed at the exposed part of the semiconductor body.
Claim 9
Dependent Claim
64 words
A method according to claim 6, wherein the first patterned oxidation resistant layer includes first and second stacked films, the second film being stacked on the first film; and wherein, in removing the second patterned oxidation resistant layer, at least the first stacked film is left such that the semiconductor body is not exposed in the area of the first patterned oxidation resistant layer.
Claim 10
Dependent Claim
31 words
A method according to claim 8, wherein the removing the second patterned oxidation resistant layer is performed so as to expose the semiconductor body under the second patterned oxidation resistant layer.
Claim 11
Dependent Claim
19 words
A method according to claim 1, wherein said groove is formed using said thick oxidation film as a mask.
Claim 12
Dependent Claim
34 words
A method according to claim 10, comprising the further step of forming wiring layers on the thick oxidation film on the inactive region, said wiring layers being used for interconnecting between the semiconductor elements.
Claim 13
Dependent Claim
32 words
A method according to claim 1, wherein said groove is sufficiently deep extending from the main surface so as to electrically isolate the semiconductor elements to be formed in the active regions.
Claim 14
Dependent Claim
34 words
A method according to claim 1, comprising the further step of forming wiring layers on the thick oxidation film on the inactive region, said wiring layer being used for interconnecting between the semiconductor elements.
Claim 15
Independent Claim
128 words
A method of manufacturing a semiconductor substrate, comprising the steps of: (a) selectively forming a thick oxidation film on an inactive region of a main surface of a semiconductor body, said inactive region being a region in which semiconductor elements are not formed, said thick oxidation film being formed by thermal oxidation of said semiconductor body; (b) after the step (a), forming a groove in said semiconductor body so as to surround active regions of said main surface in which said semiconductor elements are to be formed, said groove being formed in a region of the semiconductor body other than the inactive region; and (c) forming wiring layers on the thick oxidation film on the inactive region, said wiring layers being used for interconnecting between the semiconductor elements.
Claim 16
Independent Claim
128 words
A method of manufacturing a semiconductor substrate, comprising the steps of: (a) selectively forming a thick oxidation film on an inactive region of a main surface of a semiconductor body, said inactive region being a region in which semiconductor elements are not formed, said thick oxidation film being formed by thermal oxidation of said semiconductor body; (b) after the step (a), forming a groove in said semiconductor body so as to surround active regions of said main surface in which said semiconductor elements are to be formed, said groove being formed in a region of the semiconductor body other than the inactive region; and (c) forming wiring layers on the thick oxidation film on the inactive region, said wiring layers being used for interconnecting between the semiconductor elements.
Claim 17
Dependent Claim
32 words
A method according to claim 14, wherein said groove is sufficiently deep extending from the main surface so as to electrically isolate the semiconductor elements to be formed in the active regions.
Claim 18
Dependent Claim
18 words
A method according to claim 14, wherein said material used to fill said groove is an insulating material.
Claim 19
Dependent Claim
33 words
A method according to claim 14, including the further step of covering surfaces of the semiconductor body exposed within the groove with an insulating material, prior to filling said groove with said material.
Claim 20
Dependent Claim
36 words
A method according to claim 17, wherein said material filling said groove is an electrically conducting material, and wherein the method includes the further step of forming an insulating material on said material filling the groove.
Claim 21
Dependent Claim
15 words
A method according to claim 14, wherein the groove is formed by reactive ion etching.
Claim 22
Dependent Claim
16 words
A method according to claim 14, wherein the groove is formed adjacent said thick oxide film.
Claim 23
Independent Claim
226 words
A method of manufacturing a semiconductor device, comprising the steps of: (a) selectively forming an oxidation impermeable mask on a main surface of a semiconductor body, said mask covering a plurality of first regions of said main surface in which semiconductor elements are to be respectively formed and a second region of said main surface in which an isolation region is to be formed, wherein said second region surrounds each of said plurality of first regions; (b) oxidizing a third region of said main surface exposed from said oxidation impermeable mask by employing said oxidation impermeable mask, thereby to selectively form a thick oxide film in said third region; (c) after the step (b), grooving said second region of said main surface of said semiconductor body, thereby to form an isolation groove in said second region, said isolation groove extending with a depth electrically isolating said main surface of said semiconductor body into said plurality of said first regions; (d) filling said isolation groove with a material so as to form an isolation structure; (e) forming said semiconductor elements in said first regions, each of said semiconductor elements having a thin oxidation film which is thinner than said thick oxide film; and (f) forming wiring layers on said thick oxide film in said third region, said wiring layers being used for interconnecting between said semiconductor elements.
Claim 24
Independent Claim
226 words
A method of manufacturing a semiconductor device, comprising the steps of: (a) selectively forming an oxidation impermeable mask on a main surface of a semiconductor body, said mask covering a plurality of first regions of said main surface in which semiconductor elements are to be respectively formed and a second region of said main surface in which an isolation region is to be formed, wherein said second region surrounds each of said plurality of first regions; (b) oxidizing a third region of said main surface exposed from said oxidation impermeable mask by employing said oxidation impermeable mask, thereby to selectively form a thick oxide film in said third region; (c) after the step (b), grooving said second region of said main surface of said semiconductor body, thereby to form an isolation groove in said second region, said isolation groove extending with a depth electrically isolating said main surface of said semiconductor body into said plurality of said first regions; (d) filling said isolation groove with a material so as to form an isolation structure; (e) forming said semiconductor elements in said first regions, each of said semiconductor elements having a thin oxidation film which is thinner than said thick oxide film; and (f) forming wiring layers on said thick oxide film in said third region, said wiring layers being used for interconnecting between said semiconductor elements.
Claim 25
Dependent Claim
42 words
A method according to claim 21, including a further step of removing said oxidation impermeable mask on said second region of said main surface of said semiconductor body, prior to grooving said second region of said main surface of said semiconductor body.
Claim 26
Independent Claim
331 words
A method of manufacturing a semiconductor device, comprising the steps of: (a) preparing a semiconductor body including a semiconductor substrate of a first conductivity type, a buried semiconductor layer of a second conductivity type opposite to said first conductivity type, said buried semiconductor layer being provided on said substrate, and an epitaxial semiconductor layer of said second conductivity type, said epitaxial semiconductor layer being provided on said buried semiconductor layer, said semiconductor body having a main surface corresponding to an upper surface of said epitaxial semiconductor layer; (b) selectively forming an oxidation impermeable mask on said main surface of said semiconductor body, said mask covering a plurality of first regions of said main surface in which semiconductor elements are to respectively formed and a second region of said main surface in which an isolation region is to be formed, wherein said second region surrounds each of said plurality of said first regions; (c) oxidizing a third region of said main surface exposed from said oxidation impermeable mask by employing said oxidation impermeable mask, thereby to selectively form a thick oxide film in said third region; (d) after the step (c), grooving said second region of said main surface of said semiconductor body, thereby to form an isolation groove in said second region, wherein said isolation groove reaches said semiconductor substrate of said first conductivity type through said buried semiconductor layer and electrically isolates said main surface of said semiconductor body into said plurality of said first regions; (e) filling said isolation groove with a material so as to form an isolation structure; (f) forming bipolar transistors in said first regions, each said bipolar transistor having at least one PN junction extending to said main surface and a thin oxide film covering said PN junction, wherein said thin oxide film is thinner than said thick oxide film; and (g) forming wiring layers on said thick oxide film in said third region, said wiring layers being used for interconnecting between said bipolar transistors.
Claim 27
Independent Claim
331 words
A method of manufacturing a semiconductor device, comprising the steps of: (a) preparing a semiconductor body including a semiconductor substrate of a first conductivity type, a buried semiconductor layer of a second conductivity type opposite to said first conductivity type, said buried semiconductor layer being provided on said substrate, and an epitaxial semiconductor layer of said second conductivity type, said epitaxial semiconductor layer being provided on said buried semiconductor layer, said semiconductor body having a main surface corresponding to an upper surface of said epitaxial semiconductor layer; (b) selectively forming an oxidation impermeable mask on said main surface of said semiconductor body, said mask covering a plurality of first regions of said main surface in which semiconductor elements are to respectively formed and a second region of said main surface in which an isolation region is to be formed, wherein said second region surrounds each of said plurality of said first regions; (c) oxidizing a third region of said main surface exposed from said oxidation impermeable mask by employing said oxidation impermeable mask, thereby to selectively form a thick oxide film in said third region; (d) after the step (c), grooving said second region of said main surface of said semiconductor body, thereby to form an isolation groove in said second region, wherein said isolation groove reaches said semiconductor substrate of said first conductivity type through said buried semiconductor layer and electrically isolates said main surface of said semiconductor body into said plurality of said first regions; (e) filling said isolation groove with a material so as to form an isolation structure; (f) forming bipolar transistors in said first regions, each said bipolar transistor having at least one PN junction extending to said main surface and a thin oxide film covering said PN junction, wherein said thin oxide film is thinner than said thick oxide film; and (g) forming wiring layers on said thick oxide film in said third region, said wiring layers being used for interconnecting between said bipolar transistors.
Claim 28
Dependent Claim
42 words
A method according to claim 23, including a further step of removing said oxidation impermeable mask on said second region of said main surface of said semiconductor body, prior to grooving said second region of said main surface of said semiconductor body.
Claim 29
Dependent Claim
60 words
A method according to claim 23, wherein the step of forming bipolar transistors includes a step of introducing an impurity of said first conductivity type into each of said first regions, thereby to form a doped semiconductor region of said first conductivity type in each of said first regions, serving as a base region of each of said bipolar transistors.
Claim 30
Dependent Claim
35 words
A method according to claim 25, wherein said doped semiconductor region of said first conductivity type together with said epitaxial semiconductor layer of said second conductivity type forms said PN junction of said bipolar transistor.
Claim 31
Dependent Claim
44 words
A method according to claim 26, wherein said epitaxial semiconductor layer of said second conductivity type in said first region is a collector region of said bipolar transistor, and wherein said thin oxide film covers said PN junction of said base and collector regions.
Claim 32
Independent Claim
245 words
A method of manufacturing a semiconductor device, comprising the steps of: (a) forming a thin oxide film on a main surface of a semiconductor body; (b) selectively forming an oxidation impermeable mask on said thin oxide film on said main surface of said semiconductor body, said mask covering a plurality of first regions of said main surface in which semiconductor elements are to be respectively formed and a second region of said main surface in which an isolation region is to be formed, wherein said second region surrounds each of said plurality of said first regions; (c) oxidizing a third region of said main surface exposed from said oxidation impermeable mask by employing said oxidation impermeable mask, thereby to selectively form a thick oxide film in said third region thicker than said thin oxide film, the third region being a separate region from the second region; (d) after the step (c), grooving said second region of said main surface of said semiconductor body, thereby to form an isolation groove in said second region, said isolation groove extending with a depth electrically isolating said main surface of said semiconductor body into said plurality of said first regions; (e) filling said isolation groove with a material so as to form an isolation structure; (f) forming said semiconductor elements in said first regions; and (g) forming wiring layers on said thick oxide film in said third region, said wiring layers being used for interconnecting between said semiconductor elements.
Claim 33
Independent Claim
245 words
A method of manufacturing a semiconductor device, comprising the steps of: (a) forming a thin oxide film on a main surface of a semiconductor body; (b) selectively forming an oxidation impermeable mask on said thin oxide film on said main surface of said semiconductor body, said mask covering a plurality of first regions of said main surface in which semiconductor elements are to be respectively formed and a second region of said main surface in which an isolation region is to be formed, wherein said second region surrounds each of said plurality of said first regions; (c) oxidizing a third region of said main surface exposed from said oxidation impermeable mask by employing said oxidation impermeable mask, thereby to selectively form a thick oxide film in said third region thicker than said thin oxide film, the third region being a separate region from the second region; (d) after the step (c), grooving said second region of said main surface of said semiconductor body, thereby to form an isolation groove in said second region, said isolation groove extending with a depth electrically isolating said main surface of said semiconductor body into said plurality of said first regions; (e) filling said isolation groove with a material so as to form an isolation structure; (f) forming said semiconductor elements in said first regions; and (g) forming wiring layers on said thick oxide film in said third region, said wiring layers being used for interconnecting between said semiconductor elements.
Claim 34
Dependent Claim
21 words
A method according to claim 28, wherein the step of forming said semiconductor elements includes a step of forming bipolar transistors.
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