US5223081A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for roughening a silicon or polysilicon surface for a semiconductor substrate
Assignee: Micron Technology Inc
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Filing: 1991-07-03
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Granted: 1993-06-29
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Expires: 2011-07-03
Abstract
Abstract This invention relates to a method for roughening a silicon or polysilicon substrate of a semiconductor. The method includes the steps of: depositing a metal layer onto the substrate, heating the metal layer and substrate through to form a metal silicide on the substrate by reaction of the metal layer and substrate, and removing the metal silicide and a metal oxide by selective etching to expose the roughened surface. The actual etching process may be a two-step procedure. A first etch uses ammonium hydroxide and hydrogen peroxide to remove the oxide layer formed with the silicide. A second etch uses hydrofluoric acid to remove the silicide.
Inventors
- 👤 Trung T. Doan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:08
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/692; H10D1/711; H10D1/712; H10P; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667; Y; Y10; Y10S; Y10S438/00; Y10S438/964
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
102 words
In semiconductor manufacture a method for roughening a surface of a silicon or polysilicon substrate comprising: depositing a metal layer on the substrate; heating the substrate and metal layer in an atmosphere to initiate a chemical reaction between the metal layer and substrate to from a metal silicide layer on the substrate and to form a metal oxide-nitride layer on the metal silicide layer; removing the metal oxide-nitride layer with an etchant; and then removing the metal silicide layer with a selective etchant, thereby exposing a roughened surface area on the substrate t a boundary of the substrate and metal silicide layer.
Claim 2
Dependent Claim
102 words
In semiconductor manufacture a method for roughening a surface of a silicon or polysilicon substrate comprising: depositing a metal layer on the substrate; heating the substrate and metal layer in an atmosphere to initiate a chemical reaction between the metal layer and substrate to from a metal silicide layer on the substrate and to form a metal oxide-nitride layer on the metal silicide layer; removing the metal oxide-nitride layer with an etchant; and then removing the metal silicide layer with a selective etchant, thereby exposing a roughened surface area on the substrate t a boundary of the substrate and metal silicide layer.
Claim 3
Dependent Claim
25 words
The method as recited in claim 1 wherein: the metal layer is deposited to a thickness of between about 50 and about 3000 Angstrom (Å).
Claim 4
Dependent Claim
17 words
The method as recited in claim 2 and wherein: the metal layer thickness is about 500 Å.
Claim 5
Dependent Claim
16 words
The method as recited in claim 1 and wherein: the metal layer is a refractory metal.
Claim 6
Dependent Claim
15 words
The method as recited in claim 4 and wherein: the metal layer is titanium (Ti).
Claim 7
Dependent Claim
29 words
The method as recited in claim 5 and wherein: the metal silicide layer is titanium silicide (TiSi x ) and is removed by exposure to a hydrofluoric acid solution.
Claim 8
Dependent Claim
41 words
The method as recited in claim 6 and wherein: the metal oxide-nitride layer is titanium oxide-nitride (TiN x O y ) and is removed with a solution of ammonium hydroxide (NH 4 OH) and hydrogen peroxide (H 2 O 2 ).
Claim 9
Dependent Claim
131 words
In semiconductor manufacture a method for roughening a surface of a silicon or polysilicon substrate comprising: depositing a titanium layer on the substrate; heating the substrate and titanium layer in an atmosphere to a temperature for causing a chemical reaction that creates a titanium silicide (TiSi x ) layer on the substrate with a rough and irregular grain boundary and a titanium oxide-nitride (TiN x O y ) layer on the titanium silicide (TiSi x ) layer; and then removing the titanium oxide-nitride (TiN x O y ) layer with an etchant and removing the titanium silicide (TiSi x ) layer with an etchant selective to titanium silicide (TiSi x ) thereby exposing a roughened surface area on the substrate at the boundary between the silicide, and silicon or polysilicon substrate.
Claim 10
Dependent Claim
131 words
In semiconductor manufacture a method for roughening a surface of a silicon or polysilicon substrate comprising: depositing a titanium layer on the substrate; heating the substrate and titanium layer in an atmosphere to a temperature for causing a chemical reaction that creates a titanium silicide (TiSi x ) layer on the substrate with a rough and irregular grain boundary and a titanium oxide-nitride (TiN x O y ) layer on the titanium silicide (TiSi x ) layer; and then removing the titanium oxide-nitride (TiN x O y ) layer with an etchant and removing the titanium silicide (TiSi x ) layer with an etchant selective to titanium silicide (TiSi x ) thereby exposing a roughened surface area on the substrate at the boundary between the silicide, and silicon or polysilicon substrate.
Claim 11
Dependent Claim
37 words
The method as recited in claim 8 and wherein: the titanium oxide-nitride (TiN x O y ) layer is removed with a solution of ammonium hydroxide (NH 4 OH) and hydrogen peroxide (H 2 O 2 ).
Claim 12
Dependent Claim
41 words
The method as stated in claim 9 and wherein: the titanium oxide-nitirde (TiN x O y ) layer is removed by exposing the titanium oxide-nitride (TiN x O y ) layer to a 1:1 solution of ammonium hydroxide and hydrogen peroxide.
Claim 13
Dependent Claim
26 words
The method as stated in claim 9 and wherein: the titanium layer thickness is deposited to a thickness between about 50 and about 3000 Angstrom (Å).
Claim 14
Dependent Claim
17 words
The method as stated in claim 11 and wherein: the titanium layer thickness is about 500 Å.
Claim 15
Dependent Claim
31 words
The method as stated in claim 8 and wherein: the titanium silicide (TiSi x ) layer is removed by exposing the titanium silicide (TiSi x ) to a hydrofluoric acid solution.
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| 3.5 Years (Year 4) | 1996-06-28 | 1996-12-28 | 1997-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-28 | 2000-12-28 | 2001-06-29 | $3760.00 | Window Closed / Lapsed |
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