EP0523856A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of via formation for multilevel interconnect integrated circuits
Assignee: STMicroelectronics lnc USA
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Filing: 1992-06-17
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Granted: —
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Expires: 2012-06-17
Abstract
Abstract A method is provided for depositing a silicon nitride layer (38) to protect and isolate underlying layers (16,20) during wet etching. The silicon nitride layer (38) maintains the integrity of interconnect leads, bond pads, and die boundaries by acting as a wet etch stop. The silicon nitride layer (38) stops the chemicals used in a wet etch from reaching underlying layers (16,20) in the integrated circuit.
Inventors
- 👤 Alexander Kalnitsky
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 20:45
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/081; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; Y; Y10; Y10S; Y10S438/00; Y10S438/97
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
124 words
A contact structure on a semiconductor integrated circuit, comprising: a conductive element; a first dielectric layer overlying said conductive element; a second dielectric layer overlying said first dielectric layer; a third dielectric layer overlying said second dielectric layer; wherein said second dielectric layer is made of material that is not etched by a chemical wet etch that etches said third dielectric layer; an opening through said first, second and third dielectric layers to expose a portion of said conductive element; wherein the upper portion of said opening is the result of a chemical wet etch; a second conductive element overlying portions of said third dielectric layer and extending into said opening; wherein said second conductive element makes electrical contact with said first conductive element.
Claim 2
Dependent Claim
12 words
The contact structure of claim 1, wherein said conductive element is interconnect.
Claim 3
Dependent Claim
21 words
The contact structure of claim 1, wherein the upper portion of said opening extends only partially through said third dielectric layer.
Claim 4
Dependent Claim
159 words
A contact structure on a semiconductor integrated circuit, comprising: a conductive region; a first dielectric layer overlying said conductive region; an opening through said dielectric layer to expose a portion of said conductive region; a first conductive layer overlying portions of said first dielectric layer and extending into said opening; wherein said first conductive layer makes electrical contact with said conductive region; a second dielectric layer overlying said first conductive layer and said first dielectric layer; a third dielectric layer overlying portions of said second dielectric layer; a fourth dielectric layer overlying said second and third dielectric layers; a fifth dielectric layer overlying said fourth dielectric layer; a second opening through said fifth, fourth, third and second dielectric layers to expose a portion of said first conductive layer; and a second conductive layer overlying portions of said fifth dielectric layer and extending into said second opening; wherein said second conductive layer makes electrical contact with said first conductive layer.
Claim 5
Dependent Claim
16 words
The contact structure of claim 4, wherein said third dielectric layer comprises a spin on glass.
Claim 6
Dependent Claim
28 words
The contact structure of claim 5, wherein the upper surface of said third dielectric layer is more nearly planar than the upper surface of said second dielectric layer.
Claim 7
Dependent Claim
18 words
The contact structure of claim 4, wherein said second and fifth dielectric layers comprise substantially undoped silicon oxide.
Claim 8
Dependent Claim
17 words
The contact structure of claim 4, wherein said first and second conductive layers comprise a conductive metal.
Claim 9
Dependent Claim
17 words
The contact structure of claim 4, wherein said first and second conductive layers comprise silicided polycrystalline silicon.
Claim 10
Dependent Claim
14 words
The contact structure of claim 4, wherein said fourth dielectric layer comprises silicon nitride.
Claim 11
Dependent Claim
21 words
The contact structure of claim 4, wherein said second, fourth and fifth dielectric layers are conformal with their respective underlying structure.
Claim 12
Dependent Claim
21 words
The contact structure of claim 4, wherein the upper portion of said second opening is the result of a wet etch.
Claim 13
Dependent Claim
34 words
The contact structure of claim 1 or 2, wherein the lower portion of said opening, the upper portion of which is the result of a wet etch, is the result of an anisotropic etch.
Claim 14
Dependent Claim
29 words
The contact structure of claim 13, wherein during an anisotropic etch the second dielectric layer is etched away at the same time and along with said third dielectric layer.
Claim 15
Independent Claim
128 words
A method for forming an integrated circuit contact structure, comprising the steps of: forming a conductive element; forming a first dielectric layer over the conductive element; forming a second dielectric layer over said first dielectric layer; forming a third dielectric layer over said second dielectric layer, wherein the second dielectric layer is made of a material that is not etched by a chemical wet etch that etches said third dielectric layer; deposit and pattern a photoresist layer over said third dielectric layer; form an opening through said first, second and third dielectric layers by performing an isotropic chemical etch through a portion of the third dielectric layer, followed by an anisotropic etch through the first, second and third dielectric layers to expose a portion of the conductive element.
Claim 16
Dependent Claim
29 words
The contact structure of claim 1, or the method of claim 15, wherein filler regions are formed along vertical sidewalls and in lower topographical areas on the integrated circuit.
Claim 17
Dependent Claim
16 words
The contact structure or method of claim 16, wherein said filler regions comprise spin on glass.
Claim 18
Dependent Claim
23 words
The method of claim 17, wherein the filler regions are etched back to make the surface of a dielectric layer more nearly planar.
Claim 19
Dependent Claim
24 words
The method of claim 15, wherein said second dielectric layer is made of silicon nitride, and said third dielectric layer is made of oxide.
Claim 20
Dependent Claim
35 words
The method of claim 15, wherein a second conductive element is deposited and patterned over a portion of said third dielectric layer and extends into said opening to make electrical contact with the conductive element.
Claim 21
Dependent Claim
66 words
The method of claim 15, wherein formation of said first conductive element comprises the steps of: forming a lower dielectric layer over an underlying conductive region; forming an opening through the lower dielectric layer to a conductive area in the underlying conductive region; forming a conductor layer over portions of the lower dielectric layer and extending into the opening to make contact with the conductive area.
Claim 22
Dependent Claim
19 words
The method of claim 21, wherein said conductive area is a portion of interconnect underlying the lower dielectric layer.
Claim 23
Independent Claim
110 words
A method for forming an integrated circuit contact structure, comprising the steps of: forming a conductive element; forming a first dielectric layer over said conductive element; forming a second dielectric layer over said first dielectric layer; forming a third dielectric layer over said second dielectric layer; wherein said second dielectric layer is made of material that is not etched by a chemical wet etch which etches said third dielectric layer; deposit and pattern a photoresist layer over said third dielectric layer; forming an opening through said third dielectric layer; wherein at least a portion of the opening is formed by etching said third dielectric layer with a chemical isotropic etch.
Claim 24
Dependent Claim
21 words
The method of claim 23, wherein the chemical isotropic etch forms an opening only part way through the third dielectric layer.
Claim 25
Dependent Claim
24 words
The method of claim 23, wherein the chemical isotropic etch is followed by an anisotropic etch to expose a portion of said conductive element.
References Cited (Backward Citations)
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