US5817568A
Expired / Lapsed
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Method of forming a trench isolation region
Assignee: Winbond Electronics Corp
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Filing: 1997-06-27
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Granted: 1998-10-06
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Expires: 2017-06-27
Abstract
Abstract A method, using multi-trench formation techniques, to define the respective depths of trenches having different widths. The method includes forming a buffer oxide layer and a polishing stop layer, in sequence, above a semiconductor substrate. Then, the buffer oxide layer, the polishing stop layer and the semiconductor substrate are defined to form at least one narrow trench. Thereafter, the buffer oxide layer, the polishing stop layer and the semiconductor substrate are again defined to form at least one wide trench whose depth is less than that of the narrow trench. Alternatively, the wide trench may be etch-defined first, followed by the narrow trench. However, in both cases the depth of the wide trench will be less than that of the narrow trench. Subsequently, an oxide layer is formed, which fills the narrow and wide trenches. Next, a portion of the oxide layer and a portion of the polishing stop layer are removed to form a planarized surface. Finally, the polishing stop layer and the buffer oxide layer are removed.
Inventors
- 👤 Shun-Haw Chao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:52
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/0145; H10W10/10; H10W10/17; Y; Y10; Y10S; Y10S148/00; Y10S148/05
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
155 words
A method of forming a trench isolation region, comprising: forming, in sequence, a buffer oxide layer and a polishing stop layer above a semiconductor substrate; defining, in a first operation, the polishing stop layer, the buffer oxide layer and the semiconductor substrate to form at least one first trench; defining, in a second operation, the polishing stop layer, the buffer oxide layer and the semiconductor substrate to form at least one second trench, wherein the first trench and the second trench have different widths, and wherein a wider of the trenches has a depth which is shallower than a depth of a narrower of the trenches; filling the first trench and the second trench with an oxide layer; removing a portion of the oxide layer and a portion of the polishing stop layer, using chemical-mechanical polishing, to form a planarized surface; and removing the buffer oxide layer and a remainder of the polishing stop layer.
Claim 2
Independent Claim
155 words
A method of forming a trench isolation region, comprising: forming, in sequence, a buffer oxide layer and a polishing stop layer above a semiconductor substrate; defining, in a first operation, the polishing stop layer, the buffer oxide layer and the semiconductor substrate to form at least one first trench; defining, in a second operation, the polishing stop layer, the buffer oxide layer and the semiconductor substrate to form at least one second trench, wherein the first trench and the second trench have different widths, and wherein a wider of the trenches has a depth which is shallower than a depth of a narrower of the trenches; filling the first trench and the second trench with an oxide layer; removing a portion of the oxide layer and a portion of the polishing stop layer, using chemical-mechanical polishing, to form a planarized surface; and removing the buffer oxide layer and a remainder of the polishing stop layer.
Claim 3
Dependent Claim
31 words
The method according to claim 1, wherein said defining, in a second operation, includes forming the second trench with a width that is greater than the width of the first trench.
Claim 4
Dependent Claim
26 words
The method according to claim 2, wherein said defining, in a first operation, includes forming the first trench to a depth greater than about 0.6 μm.
Claim 5
Dependent Claim
38 words
The method according to claim 2, wherein said defining, in a second operation, includes forming the second trench with a width that is greater than about 1.0 μm, and a depth that is smaller than about 0.6 μm.
Claim 6
Dependent Claim
31 words
The method according to claim 1, wherein said defining, in a second operation, includes forming the second trench with a width that is narrower than the width of the first trench.
Claim 7
Dependent Claim
38 words
The method according to claim 5, wherein said defining, in a first operation, includes forming the first trench with a width that is greater than about 10 μm, and a depth that is smaller than about 0.6 μm.
Claim 8
Dependent Claim
26 words
The method according to claim 5, wherein said defining, in a second operation, includes forming the second trench to a depth greater than about 0.6 μm.
Claim 9
Dependent Claim
30 words
The method according to claim 1, wherein said forming includes using thermal oxidation, at a temperature between about 600° C. and about 1250° C., to form the buffer oxide layer.
Claim 10
Dependent Claim
26 words
The method according to claim 1, wherein said forming includes forming the buffer oxide layer to a thickness between about 0.01 μm and about 5 μm.
Claim 11
Dependent Claim
18 words
The method according to claim 1, wherein said forming includes comprising the polishing stop layer of a polysilicon.
Claim 12
Dependent Claim
26 words
The method according to claim 1, wherein said forming includes forming the polishing stop layer to a thickness between about 0.05 μm and about 5 μm.
Claim 13
Dependent Claim
19 words
The method according to claim 1, wherein said forming includes comprising the polishing stop layer of a silicon nitride.
Claim 14
Dependent Claim
19 words
The method according to claim 1, wherein said filling includes using sub-atmospheric vapor deposition to form the oxide layer.
Claim 15
Dependent Claim
20 words
The method according to claim 1, wherein said filling includes using tetra-ethyl-ortho-silicate/ozone as reactive gases to form the oxide layer.
Claim 16
Independent Claim
172 words
A method of forming a trench isolation region, comprising: forming, in sequence, a buffer oxide layer, a polishing stop layer and a mask oxide layer, above a semiconductor substrate; defining, in a first operation, the mask oxide layer, the polishing stop layer, the buffer oxide layer and the semiconductor substrate to form at least one first trench; defining, in a second operation, the mask oxide layer, the polishing stop layer, the buffer oxide layer and the semiconductor substrate to form at least one second trench, wherein the first trench and the second trench have different widths, and wherein a wider of the trenches has a depth which is shallower than a depth of a narrower of the trenches; removing the mask oxide layer; filling the first trench and the second trench with an oxide layer; removing a portion of the oxide layer and a portion of the polishing stop layer, using chemical-mechanical polishing, to form a planarized surface; and removing the buffer oxide layer and a remainder of the polishing stop layer.
Claim 17
Independent Claim
172 words
A method of forming a trench isolation region, comprising: forming, in sequence, a buffer oxide layer, a polishing stop layer and a mask oxide layer, above a semiconductor substrate; defining, in a first operation, the mask oxide layer, the polishing stop layer, the buffer oxide layer and the semiconductor substrate to form at least one first trench; defining, in a second operation, the mask oxide layer, the polishing stop layer, the buffer oxide layer and the semiconductor substrate to form at least one second trench, wherein the first trench and the second trench have different widths, and wherein a wider of the trenches has a depth which is shallower than a depth of a narrower of the trenches; removing the mask oxide layer; filling the first trench and the second trench with an oxide layer; removing a portion of the oxide layer and a portion of the polishing stop layer, using chemical-mechanical polishing, to form a planarized surface; and removing the buffer oxide layer and a remainder of the polishing stop layer.
Claim 18
Dependent Claim
31 words
The method according to claim 15, wherein said defining, in a second operation, includes forming the second trench with a width that is greater than the width of the first trench.
Claim 19
Dependent Claim
26 words
The method according to claim 16, wherein said defining, in a first operation, includes forming the first trench to a depth greater than about 0.6 μm.
Claim 20
Dependent Claim
38 words
The method according to claim 16, wherein said defining, in a second operation, includes forming the second trench with a width that is greater than about 1.0 μm, and a depth that is smaller than about 0.6 μm.
Claim 21
Dependent Claim
31 words
The method according to claim 15, wherein said defining, in a second operation, includes forming the second trench with a width that is narrower than the width of the first trench.
Claim 22
Dependent Claim
38 words
The method according to claim 19, wherein said defining, in a first operation, includes forming the first trench with a width that is greater than about 1.0 μm, and a depth that is smaller than about 0.6 μm.
Claim 23
Dependent Claim
26 words
The method according to claim 19, wherein said defining, in a second operation, includes forming the second trench to a depth greater than about 0.6 μm.
Claim 24
Dependent Claim
30 words
The method according to claim 15, wherein said forming includes using thermal oxidation, at a temperature between about 600° C. and about 1250° C., to form the buffer oxide layer.
Claim 25
Dependent Claim
26 words
The method according to claim 15, wherein said forming includes forming the buffer oxide layer to a thickness between about 0.01 μm and about 5 μm.
Claim 26
Dependent Claim
18 words
The method according to claim 15, wherein said forming includes comprising the polishing stop layer of a polysilicon.
Claim 27
Dependent Claim
26 words
The method according to claim 15, wherein said forming includes forming the polishing stop layer to a thickness between about 0.05 μm and about 5 μm.
Claim 28
Dependent Claim
19 words
The method according to claim 15, wherein said forming includes comprising the polishing stop layer of a silicon nitride.
Claim 29
Dependent Claim
20 words
The method according to claim 15, wherein said forming includes using chemical vapor deposition to form the mask oxide layer.
Claim 30
Dependent Claim
19 words
The method according to claim 15, wherein said filling includes using sub-atmospheric vapor deposition to form the oxide layer.
Claim 31
Dependent Claim
20 words
The method according to claim 15, wherein said filling includes using tetra-ethyl-ortho-silicate/ozone as reactive gases to form the oxide layer.
References Cited (Backward Citations)
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