EP0264692A2
Expired / Lapsed
EP
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Method of forming a bridge contact
Assignee: International Business Machines Corp
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Filing: 1987-10-02
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Granted: —
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Expires: 2007-10-02
Abstract
Abstract A method of forming a bridge contact between silicon regions (24, 32) on a substrate (10) that are separated by a first insulating region (32A) having a first lateral length, without forming a bridge contact between silicon regions on the substrate that are separated by other insulating regions that have lateral lengths that are greater than that of said first insulating region (32A), comprising the steps of: forming a refractory metal layer (14) on the substrate (10) under conditions such that said refractory metal has a substantially columnar grain structure; sintering the substrate under conditions that limit lateral silicon diffusion, so that a silicide (14A) is formed over all of said silicon regions and said first insulation region (32A) without forming a silicide over said other insulating regions; and exposing the substrate to an etchant that preferentially removes portions of said refractory metal that did not react to form said silicide (14A), without appreciably removing said silicide. The method in particular uses a self-aligned silicide reaction to form a bridging contact between portions of a semiconductor surface that are separated by a thin insulating layer.
Inventors
- 👤 Nicky Chau-Chun Lu
- 👤 Brian John Machesney
- 👤 Rick Lawrence Mohler
- 👤 Glen Lester Miles
- 👤 Chung-Yu Ting
- 👤 Stephen David Warley
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 12:04
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/0698; H10D; H10D62/00; H10D62/80; H10D62/83; H10D64/00; H10D64/60; H10D64/62; H10W20/064; H10W20/40; H10W20/482; H10W20/483; Y; Y10; Y10S; Y10S148/00; Y10S148/019; Y10S148/147
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
147 words
A method of forming a bridge contact between silicon regions on a substrate that are separated by a first insulating region having a first lateral length, without forming a bridge contact between silicon regions on the substrate that are separated by other insulating regions that have lateral lengths that are greater than that of said first insulating region, comprising the steps of: forming a refractory metal layer on the substrate under conditions such that said refractory metal has a substantially columnar grain structure; sintering the substrate under conditions that limit lateral silicon diffusion, so that a silicide is formed over all of said silicon regions and said first insulation region without forming a silicide over said other insulating regions; and exposing the substrate to an etchant that preferentially removes portions of said refractory metal that did not react to form said silicide, without appreciably removing said silicide.
Claim 2
Independent Claim
147 words
A method of forming a bridge contact between silicon regions on a substrate that are separated by a first insulating region having a first lateral length, without forming a bridge contact between silicon regions on the substrate that are separated by other insulating regions that have lateral lengths that are greater than that of said first insulating region, comprising the steps of: forming a refractory metal layer on the substrate under conditions such that said refractory metal has a substantially columnar grain structure; sintering the substrate under conditions that limit lateral silicon diffusion, so that a silicide is formed over all of said silicon regions and said first insulation region without forming a silicide over said other insulating regions; and exposing the substrate to an etchant that preferentially removes portions of said refractory metal that did not react to form said silicide, without appreciably removing said silicide.
Claim 3
Independent Claim
147 words
A method of forming a silicide bridge contact between two relatively coplanar silicon regions on a substrate that are separated by a first insulating region having a small lateral length, without forming a bridge contact between other silicon regions on the substrate that are separated by other insulating regions having lateral lengths that are greater than the lateral length of said first insulating layer, comprising the steps of: forming a layer of refractory metal under conditions such that the metal has a substantially columnar grain structure; sintering the substrate under conditions that limit the lateral formation of silicide, said refractory metal reacting with the substrate to form a silicide above said silicon regions and said first insulating region without forming a silicide above said other insulating regions; and exposing the substrate to an etchant that preferentially removes remaining portions of said refractory metal without removing said silicide.
Claim 4
Independent Claim
147 words
A method of forming a silicide bridge contact between two relatively coplanar silicon regions on a substrate that are separated by a first insulating region having a small lateral length, without forming a bridge contact between other silicon regions on the substrate that are separated by other insulating regions having lateral lengths that are greater than the lateral length of said first insulating layer, comprising the steps of: forming a layer of refractory metal under conditions such that the metal has a substantially columnar grain structure; sintering the substrate under conditions that limit the lateral formation of silicide, said refractory metal reacting with the substrate to form a silicide above said silicon regions and said first insulating region without forming a silicide above said other insulating regions; and exposing the substrate to an etchant that preferentially removes remaining portions of said refractory metal without removing said silicide.
Claim 5
Dependent Claim
34 words
Method according to claim 1 or 2, wherein said refractory metal has a grain shape in which lower portions of said grains have a lateral length that approximates that of said first insulating region.
Claim 6
Dependent Claim
21 words
Method according to any one of claims 1 to 3, wherein said refractory metal has a minimal amount of matrix material.
Claim 7
Dependent Claim
28 words
Method according to any one of claims 1 to 4, wherein said refractory metal is selected from the group consisting of titanium, tungsten, cobalt, molybdenum, nickel and tantalum.
Claim 8
Dependent Claim
32 words
Method according to any one of claims 1 to 5, wherein said substrate is sintered in a nitrogen ambient, preferably at approximately 700°C in a 95% nitrogen - 5 % hydrogen ambient.
Claim 9
Independent Claim
177 words
A method of forming a silicide bridge contact between two relatively coplanar silicon regions on a substrate that are separated by a thin insulating region having a small lateral length, without forming a bridge contact between other silicon regions on the substrate that are separated by other insulating regions having lateral lengths that are appreciably greater than the lateral length of the thin insulating layer, comprising the steps of: forming a layer of titanium metal on the substrate, the substrate being heated to a temperature at which the titanium has a substantially columnar grain structure with a minimal amount of matrix material, said grains having a lateral length that approximates said lateral length of said thin insulating region; sintering the substrate at approximately 700°C in a nitrogen atmosphere, said refractory metal reacting with the substrate to form a silicide above said silicon regions and said thin insulating region without forming a silicide above said other insulating regions; and exposing the substrate to an acid that preferentially removes remaining portions of said refractory metal without removing said silicide.
Claim 10
Independent Claim
177 words
A method of forming a silicide bridge contact between two relatively coplanar silicon regions on a substrate that are separated by a thin insulating region having a small lateral length, without forming a bridge contact between other silicon regions on the substrate that are separated by other insulating regions having lateral lengths that are appreciably greater than the lateral length of the thin insulating layer, comprising the steps of: forming a layer of titanium metal on the substrate, the substrate being heated to a temperature at which the titanium has a substantially columnar grain structure with a minimal amount of matrix material, said grains having a lateral length that approximates said lateral length of said thin insulating region; sintering the substrate at approximately 700°C in a nitrogen atmosphere, said refractory metal reacting with the substrate to form a silicide above said silicon regions and said thin insulating region without forming a silicide above said other insulating regions; and exposing the substrate to an acid that preferentially removes remaining portions of said refractory metal without removing said silicide.
Claim 11
Dependent Claim
30 words
Method according to any one of claims 1 to 7, wherein said refractory metal is formed on the substrate by evaporation techniques, preferably from a plurality of offset evaporation sources.
Claim 12
Dependent Claim
29 words
Method according to any one of claims 1 to 8, wherein said refractory metal is titanium being formed on the substrate at a temperature of approximately 370°C or higher.
Claim 13
Dependent Claim
39 words
Method according to any one of claims 1 to 9, wherein said etchant comprises a 10:1 mixture of hydrogen peroxide and sulfuric acid, respectively, or a 5:1:1 mixture of deionized water, 58% concentrated NH₄OH, and 30% concentrated H₂O₂, respectively.
References Cited (Backward Citations)
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