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US6284613B1 Expired / Lapsed US ⏱️ 0.0 years remaining

Method for forming a T-gate for better salicidation

Assignee: GlobalFoundries Singapore Pte Ltd
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Filing: 1999-11-05
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Granted: 2001-09-04
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Expires: 2019-11-05
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Abstract

Abstract A method for a T-gate and salicide process that allows narrow bottom gate widths below 0.25 μm and wide top gate widths to allow silicide gate contacts on the top of the T-gate. A dummy gate composed of an insulating material is formed over the substrate. Then we form LDD regions adjacent to the dummy gate preferably by ion implanting f (I/I) impurity ions into the substrate using the dummy gate as a mask. A pad oxide layer and dielectric layer are formed over the substrate surface. The dielectric layer over the dummy gate is removed preferably by a CMP process. We then remove the dummy gate to form a gate opening exposing the substrate surface. A gate dielectric layer is formed over the substrate surface in the gate opening. We form a polysilicon layer over the dielectric layer and the substrate surface in the gate opening. The polysilicon layer is patterned to form a T-gate. The dielectric layer is removed. We forming source/drain (S/D) regions adjacent to the T-gate by an Ion implant process. A silicide layer is formed over the T-gate and the substrate to form silicide contacts to the SID regions and gate contacts to the T-gate. Then we form a dielectric layer (ILD) over the T-gate and substrate. We form contact opening through the dielectric layer to expose the S/D regions and T-gate. We form contacts to the S/D regions and to the T-gate.

Inventors

  • 👤 Chivukula Subrahmanyam
  • 👤 Yelehanka Ramachandramurthy Pradeep
  • 👤 Ramakrishnan Rajagopal

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 08:00
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10D30/0227; H10D30/60; H10D30/601; H10D30/605; H10D64/00; H10D64/20; H10D64/27; H10D64/311; H10D64/411; H10D64/511; H10D64/517; H10D64/518; H10D64/01; H10D64/017

Claims Analysis

Total Claims: 12
Claim 1
Independent Claim 280 words
A method of forming a T-gate used with a salicide process for a semiconductor devices, comprising the steps of: a) patterning an insulating layer to form a dummy gate over a substrate; said substrate having a substrate surface; said insulation layer is patterned by forming a dummy gate resist pattern over said insulating layer using a first gate optical mask; said dummy gate resist pattern is exposed using said first optical mask, and etching said insulating layer using said dummy gate resist pattern as an etch mask; b) forming LDD regions adjacent to said dummy gate by ion implanting (I/I) impurity ions into said substrate using said dummy gate as a mask; c) forming a pad oxide layer over said substrate surface; d) forming a dielectric layer over said pad oxide layer and said dummy gate and removing said dielectric layer from over said dummy gate; e) removing said dummy gate forming a gate opening exposing said substrate surface; f) forming a gate dielectric layer over said substrate surface in said gate opening; g) forming a gate layer over said dielectric layer and said substrate surface in said gate opening; h) patterning said gate layer to form a T-gate; said T-gate filling said gate opening and extending laterally over a portion of said dielectric layer; said gate layer is patterned by using a T-gate resist pattern formed by using said first gate optical mask by over exposing a resist layer through said first optical gate mask so that the T-gate resist pattern is between 60% and 100% wider than said dummy gate resist; and i) removing said dielectric layer and said pad oxide layer leaving said T-gate over said substrate.
Claim 2
Independent Claim 280 words
A method of forming a T-gate used with a salicide process for a semiconductor devices, comprising the steps of: a) patterning an insulating layer to form a dummy gate over a substrate; said substrate having a substrate surface; said insulation layer is patterned by forming a dummy gate resist pattern over said insulating layer using a first gate optical mask; said dummy gate resist pattern is exposed using said first optical mask, and etching said insulating layer using said dummy gate resist pattern as an etch mask; b) forming LDD regions adjacent to said dummy gate by ion implanting (I/I) impurity ions into said substrate using said dummy gate as a mask; c) forming a pad oxide layer over said substrate surface; d) forming a dielectric layer over said pad oxide layer and said dummy gate and removing said dielectric layer from over said dummy gate; e) removing said dummy gate forming a gate opening exposing said substrate surface; f) forming a gate dielectric layer over said substrate surface in said gate opening; g) forming a gate layer over said dielectric layer and said substrate surface in said gate opening; h) patterning said gate layer to form a T-gate; said T-gate filling said gate opening and extending laterally over a portion of said dielectric layer; said gate layer is patterned by using a T-gate resist pattern formed by using said first gate optical mask by over exposing a resist layer through said first optical gate mask so that the T-gate resist pattern is between 60% and 100% wider than said dummy gate resist; and i) removing said dielectric layer and said pad oxide layer leaving said T-gate over said substrate.
Claim 3
Dependent Claim 95 words
The method of claim 1 which further includes at the end the following steps: a) forming source/drain (S/D) regions adjacent to said T-gate by an Ion implant process; b) forming a silicide layer over said T-gate and said substrate to form silicide contacts to the source/drain (S/D) regions and gate contacts to the T-gate; c) forming an interlevel dielectric layer over the T-gate and substrate; d) forming contact opening through said interlevel dielectric layer to expose said source/drain (S/D) regions and T-gate; and e) forming contacts to said source/drain (S/D) regions and to said T-gate.
Claim 4
Dependent Claim 14 words
The method of claim 1 wherein said insulating layer is comprised of silicon oxide.
Claim 5
Dependent Claim 19 words
The method of claim 1 wherein said dummy gate has a width of between about 0.1 and 0.35 μm.
Claim 6
Dependent Claim 13 words
The method of claim 1 wherein said dielectric layer comprised of silicon nitride.
Claim 7
Dependent Claim 19 words
The method of claim 1 wherein said gate opening having a width of between about 0.1 and 0.25 μm.
Claim 8
Dependent Claim 50 words
The method of claim 1 wherein said T-gate having a gate top with a top width of between about 0.25 and 0.5 μm and a top height between 500 and 2000 Å; and a bottom width between 0.1 and 0.35 μm; and a bottom height between 1500 and 3500 Å.
Claim 9
Dependent Claim 50 words
The method of claim 1 wherein said T-gate having a gate top with a top width of between about 0.35 and 0.5 μm and a top height between 500 and 2000 Å; and a bottom width between 0.1 and 0.25 μm; and a bottom height between 1500 and 3500 Å.
Claim 10
Dependent Claim 13 words
The method of claim 1 wherein said gate layer is comprised of polysilicon.
Claim 11
Independent Claim 420 words
A method of forming a T-gate and using a salicide process; comprising the steps of: a) forming an insulating layer over a substrate; b) forming a dummy gate resist pattern over said insulating layer using a first gate optical mask; c) patterning said insulating layer to form a dummy gate over said substrate; said substrate having a substrate surface; d) removing said gate resist pattern; e) forming LDD regions adjacent to said dummy gate by ion implanting (I/I) impurity ions into said substrate using said dummy gate as a mask; f) forming a pad oxide layer over said substrate surface; g) forming a dielectric layer over said pad oxide layer and said dummy gate and removing said dielectric layer from over said dummy gate; h) removing said dummy gate forming a gate opening exposing said substrate surface; i) forming a gate dielectric layer over said substrate surface in said gate opening; said gate opening having a width of between about 0.1 and 0.35 μm. j) forming a gate layer over said dielectric layer and said substrate surface in said gate opening; said gate layer is comprised of polysilicon; k) patterning said gate layer to form a T-gate by forming a T-gate resist pattern and etching said gate layer; said T-gate filling said gate opening and extending laterally over a portion of said dielectric layer; said gate layer is pattern using a T-gate resist pattern that is formed by exposing a resist layer using said first gate optical mask; said T-gate resist pattern is between 60% and 100% wider than said dummy gate resist pattern and where said T-gate resist pattern is formed by overexposing a resist layer thorough said first gate optical mask; said T-gate has a gate top with a top width of between about 0.35 and 0.5 μm and a top height between 500 and 2000 Å; and a bottom width between 0.1 and 0.35 μm; and a bottom height between 1500 and 3500 Å; l) removing said dielectric layer and said pad oxide layer leaving said T-gate over said substrate; m) forming source/drain (S/D) regions adjacent to said T-gate by an Ion implant process; n) forming a silicide layer over said T-gate and said substrate; to form silicide contacts to said source/drain (S/D) regions and gate contacts to the T-gate; o) forming a dielectric layer over the T-gate and substrate; p) forming contact opening through said dielectric layer to expose said source/drain regions and T-gate; and q) forming contacts to said source/drain regions and to said T-gate.
Claim 12
Independent Claim 420 words
A method of forming a T-gate and using a salicide process; comprising the steps of: a) forming an insulating layer over a substrate; b) forming a dummy gate resist pattern over said insulating layer using a first gate optical mask; c) patterning said insulating layer to form a dummy gate over said substrate; said substrate having a substrate surface; d) removing said gate resist pattern; e) forming LDD regions adjacent to said dummy gate by ion implanting (I/I) impurity ions into said substrate using said dummy gate as a mask; f) forming a pad oxide layer over said substrate surface; g) forming a dielectric layer over said pad oxide layer and said dummy gate and removing said dielectric layer from over said dummy gate; h) removing said dummy gate forming a gate opening exposing said substrate surface; i) forming a gate dielectric layer over said substrate surface in said gate opening; said gate opening having a width of between about 0.1 and 0.35 μm. j) forming a gate layer over said dielectric layer and said substrate surface in said gate opening; said gate layer is comprised of polysilicon; k) patterning said gate layer to form a T-gate by forming a T-gate resist pattern and etching said gate layer; said T-gate filling said gate opening and extending laterally over a portion of said dielectric layer; said gate layer is pattern using a T-gate resist pattern that is formed by exposing a resist layer using said first gate optical mask; said T-gate resist pattern is between 60% and 100% wider than said dummy gate resist pattern and where said T-gate resist pattern is formed by overexposing a resist layer thorough said first gate optical mask; said T-gate has a gate top with a top width of between about 0.35 and 0.5 μm and a top height between 500 and 2000 Å; and a bottom width between 0.1 and 0.35 μm; and a bottom height between 1500 and 3500 Å; l) removing said dielectric layer and said pad oxide layer leaving said T-gate over said substrate; m) forming source/drain (S/D) regions adjacent to said T-gate by an Ion implant process; n) forming a silicide layer over said T-gate and said substrate; to form silicide contacts to said source/drain (S/D) regions and gate contacts to the T-gate; o) forming a dielectric layer over the T-gate and substrate; p) forming contact opening through said dielectric layer to expose said source/drain regions and T-gate; and q) forming contacts to said source/drain regions and to said T-gate.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2004-09-03 2005-03-05 2005-09-04 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2008-09-03 2009-03-05 2009-09-04 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2012-09-03 2013-03-05 2013-09-04 $7700.00 Window Closed / Lapsed

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