US5244534A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Two-step chemical mechanical polishing process for producing flush and protruding tungsten plugs
Assignee: Round Rock Research LLC
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Filing: 1992-01-24
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Granted: 1993-09-14
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Expires: 2012-01-24
Abstract
Abstract A method for forming conductive plugs within an insulation material is described. The inventive process results in a plug of a material such as tungsten which is more even with the insulation layer surface than conventional plug formation techniques. Conventional processes result in recessed plugs which are not easily or reliably coupled with subsequent layers of sputtered aluminum or other conductors. The inventive process uses a two-step chemical mechanical planarization technique. An insulation layer with contact holes is formed, and a metal layer is formed thereover. A polishing pad rotates against the wafer surface while a slurry selective to the metal removes the metal overlying the wafer surface, and also recesses the metal within the contact holes due to the chemical nature and fibrous element of the polishing pad. A second CMP step uses a slurry having an acid or base selective to the insulation material to remove the insulator from around the metal. The slurry also contains abrasive materials which polish the metal surface so as to make the metal level with the insulation layer surface. Removal of the insulation material can continue, thereby producing a slightly protruding plug which result sin a more reliable contact from the substrate to subsequent conductive layers.
Inventors
- 👤 Chris C. Yu
- 👤 Trung T. Doan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 00:48
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/092; C; C23; C23F; C23F3/00; H10P; H10P52/00; H10P52/40; H10P52/403; H10W20/031; H10W20/062
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
165 words
A method of producing a conductive plug in an insulation layer, comprising the steps of: a) removing a portion of the insulation layer to form a contact hole within the insulation layer; b) applying a layer of conductive material to a surface of the insulation layer, thereby filling said contact hole with said conductive material and resulting in a layer of said conductive material over said insulation layer surface; c) removing at least a portion of said conductive material from said surface of the insulation layer and leaving said contact hole substantially filled with said conductive material, said removing being performed by chemical mechanical planarization with a slurry comprising an abrasive material and an oxidizing component, said oxidizing component comprising hydrogen peroxide and water wherein a ratio by volume of hydrogen peroxide to water is in the range of 1:0 to 1:1; d) removing some of the insulation layer to lower said insulation layer surface with respect to an upper surface of said conductive material.
Claim 2
Independent Claim
165 words
A method of producing a conductive plug in an insulation layer, comprising the steps of: a) removing a portion of the insulation layer to form a contact hole within the insulation layer; b) applying a layer of conductive material to a surface of the insulation layer, thereby filling said contact hole with said conductive material and resulting in a layer of said conductive material over said insulation layer surface; c) removing at least a portion of said conductive material from said surface of the insulation layer and leaving said contact hole substantially filled with said conductive material, said removing being performed by chemical mechanical planarization with a slurry comprising an abrasive material and an oxidizing component, said oxidizing component comprising hydrogen peroxide and water wherein a ratio by volume of hydrogen peroxide to water is in the range of 1:0 to 1:1; d) removing some of the insulation layer to lower said insulation layer surface with respect to an upper surface of said conductive material.
Claim 3
Dependent Claim
13 words
The method of claim 1, wherein said contact hole is formed by etching.
Claim 4
Dependent Claim
15 words
The method of claim 1, wherein said conductive layer is formed by chemical vapor deposition.
Claim 5
Dependent Claim
12 words
The method of claim 1, wherein said abrasive material comprises aluminum oxide.
Claim 6
Dependent Claim
14 words
The method of claim 1, wherein step d) is done by chemical mechanical planarization.
Claim 7
Dependent Claim
30 words
The method of claim 5, wherein step d) comprises the use of a slurry having an abrasive material and a compound which selectively removes a portion of the insulation layer.
Claim 8
Dependent Claim
11 words
The method of claim 6, wherein said abrasive material comprises silica.
Claim 9
Dependent Claim
11 words
The method of claim 6, wherein said compound comprises potassium hydroxide.
Claim 10
Dependent Claim
19 words
The method of claim 1, wherein between 0.5KÅ and 3KÅ of the substrate material is removed during step d).
Claim 11
Dependent Claim
25 words
The method of claim 1, wherein step d) continues until said insulation layer surface is substantially even with said upper surface of said conductive material.
Claim 12
Dependent Claim
36 words
The method of claim 1, wherein step d) continues until said insulation layer surface is lower than said upper surface of said conductive material, thereby resulting in said conductive material protruding from said insulation layer surface.
Claim 13
Dependent Claim
11 words
The method of claim 1, wherein the plug formed comprises tungsten.
Claim 14
Dependent Claim
23 words
The method of claim 12, wherein during step c) a portion of said tungsten reacts with said hydrogen peroxide to form tungsten oxide.
Claim 15
Dependent Claim
14 words
The method of claim 1, wherein the insulation layer comprises an insulating dielectric layer.
Claim 16
Dependent Claim
20 words
The method of claim 14, wherein between 0.5 KÅ and 3KÅ of the substrate material is removed in step d).
Claim 17
Dependent Claim
11 words
The method of claim 1, wherein the substrate material comprises polyimide.
Claim 18
Independent Claim
180 words
A method of chemical mechanical planarization of an oxide material, comprising the steps of: a) etching a portion of the oxide material to form a contact hole within said oxide material; b) applying a layer of tungsten to a surface of the oxide material, thereby filling said contact hole with said tungsten and resulting in a layer of said tungsten material over said oxide material; c) chemically and mechanically removing at least a portion of said tungsten from said surface of said oxide material with a first solution comprising H 2 O 2 water, and an abrasive material, and leaving said contact hole substantially filed with said tungsten, wherein a ratio by a volume of said H 2 O 2 to said water is in the range of 1:0 to 1:1; d) chemically and mechanically removing a portion of the oxide material with a second solution comprising KOH and an abrasive material to lower said surface of said oxide material with respect to an upper surface of said tungsten; whereby a plug of tungsten is formed in said contact hole.
Claim 19
Independent Claim
180 words
A method of chemical mechanical planarization of an oxide material, comprising the steps of: a) etching a portion of the oxide material to form a contact hole within said oxide material; b) applying a layer of tungsten to a surface of the oxide material, thereby filling said contact hole with said tungsten and resulting in a layer of said tungsten material over said oxide material; c) chemically and mechanically removing at least a portion of said tungsten from said surface of said oxide material with a first solution comprising H 2 O 2 water, and an abrasive material, and leaving said contact hole substantially filed with said tungsten, wherein a ratio by a volume of said H 2 O 2 to said water is in the range of 1:0 to 1:1; d) chemically and mechanically removing a portion of the oxide material with a second solution comprising KOH and an abrasive material to lower said surface of said oxide material with respect to an upper surface of said tungsten; whereby a plug of tungsten is formed in said contact hole.
Claim 20
Dependent Claim
19 words
The method of claim 17, wherein between 0.5KÅ and 3KÅ of said oxide material is removed during step d).
Claim 21
Dependent Claim
26 words
The method of claim 17, wherein step d) continues until said surface of said oxide material is substantially even with said upper surface of said tungsten.
Claim 22
Dependent Claim
36 words
The method of claim 17, wherein step d) continues until said surface of said oxide material is lower than said upper surface of said conductive material, thereby resulting in said tungsten protruding from the oxide material.
Claim 23
Independent Claim
238 words
A method of producing a conductive plug in an insulation layer, comprising the steps of: a) removing a portion of the insulation layer to form a contact hole within the insulation layer; b) applying a layer of conductive material to a surface of the insulation layer, thereby filling said contact hole with said conductive material and resulting in a layer of said conductive material over said insulation layer surface; c) removing at least a portion of said conductive material from said surface of the insulation layer and leaving said contact hole substantially filled with said conductive material; d) removing some of the insulation layer by chemical mechanical planarization using a slurry, said slurry having an abrasive material and a compound which selectively removes a portion of said insulation layer to lower said insulation layer surface with respect to an upper surface of said conductive material; e) removing at least a portion of said conductive material from said surface of the insulation layer and leaving said contact hole substantially filled with said conductive material, said removing being performed by chemical mechanical planarization with a slurry comprising an abrasive material and an oxidizing component and a carrier, wherein a ratio by volume of the oxidizing component to the carrier is in the range of 1:0 to 1:1; f) removing some of the insulation layer to lower said insulation layer surface with respect to an upper surface of said conductive material.
Claim 24
Independent Claim
238 words
A method of producing a conductive plug in an insulation layer, comprising the steps of: a) removing a portion of the insulation layer to form a contact hole within the insulation layer; b) applying a layer of conductive material to a surface of the insulation layer, thereby filling said contact hole with said conductive material and resulting in a layer of said conductive material over said insulation layer surface; c) removing at least a portion of said conductive material from said surface of the insulation layer and leaving said contact hole substantially filled with said conductive material; d) removing some of the insulation layer by chemical mechanical planarization using a slurry, said slurry having an abrasive material and a compound which selectively removes a portion of said insulation layer to lower said insulation layer surface with respect to an upper surface of said conductive material; e) removing at least a portion of said conductive material from said surface of the insulation layer and leaving said contact hole substantially filled with said conductive material, said removing being performed by chemical mechanical planarization with a slurry comprising an abrasive material and an oxidizing component and a carrier, wherein a ratio by volume of the oxidizing component to the carrier is in the range of 1:0 to 1:1; f) removing some of the insulation layer to lower said insulation layer surface with respect to an upper surface of said conductive material.
Claim 25
Dependent Claim
11 words
The method of claim 21, wherein said abrasive material comprises silica.
Claim 26
Dependent Claim
11 words
The method of claim 21, wherein said compound comprises potassium hydroxide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1996-09-13 | 1997-03-15 | 1997-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-13 | 2001-03-15 | 2001-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-13 | 2005-03-15 | 2005-09-14 | $7700.00 | Window Closed / Lapsed |