Method for cleaning a gate stack

• US 7,396,773 B1
• Filed: 12/06/2002
• Issued: 07/08/2008
• Est. Priority Date: 12/06/2002
• Status: Expired due to Fees

• Current Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Blosse, Alain, Ramkumar, Krishnaswamy
• Primary Examiner(s): Tran, Binh X
• Application Number:
  US10/313,283
• Time in Patent Office: 2,041 Days
• Field of Search: 438/745, 438/747, 438/750, 438/753, 438/754
• US Class Current: 438/747
• CPC Class Codes: C11D 2111/22 Electronic devices, e.g. PCBs or semiconductors
• CPC Class Codes: C11D 7/261 Alcohols; Phenols
• CPC Class Codes: C11D 7/263 Ethers
• CPC Class Codes: C11D 7/3218 Alkanolamines or alkanolimines
• CPC Class Codes: C11D 7/3227 Ethers thereof
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• CPC Class Codes: H01L 21/02071 the processing being a delineation, e.g. RIE, of conductive layers
• CPC Class Codes: H01L 21/28247 passivation or protection of the electrode, e.g. using re-oxidation
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/31138 by dry-etching
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: H01L 21/32137 of silicon-containing layers

Abstract

A method of making a semiconductor structure, comprises cleaning a gate stack with a cleaning solution. The gate stack comprises a gate layer, a metallic layer on the gate layer, and a etch-stop layer on the metallic layer. The gate layer is on a semiconductor substrate, the cleaning solution is a non-oxidizing cleaning solution, and the metallic layer comprises an easily oxidized metal.

Claims

1. A method of making a semiconductor structure, comprising:

cleaning a gate stack with a cleaning solution;

wherein the gate stack comprises a gate layer, a metallic layer on the gate layer, and an etch-stop layer on the metallic layer,

the gate layer is on a semiconductor substrate,

the cleaning solution is a non-oxidizing cleaning solution,

the metallic layer comprises an easily oxidized metal, and

the cleaning solution consists essentially of;

(a) at least one member selected from the group consisting of an amino alcohol and amino ether,

(b) at least one member selected from the group consisting of an aromatic alcohol, aliphatic polyol, and aliphatic polyol ether, and

(c) a hydroxyl amine.

2. The method of claim 1, wherein the metallic layer comprises tungsten or titanium.

3. The method of claim 1, wherein the cleaning solution consists essentially of:

(a) an amino alkoxy alcohol having 2-12 carbon atoms,

(b) an aromatic diol or triol, and

(c) hydroxylamine or an alkylhydroxylamine containing 1-6 carbon atoms.

4. The method of claim 1, wherein the cleaning solution consists essentially of 2-(2 aminoethoxy)ethanol, hydroxylamine, and catechol.

5. The method of claim 1, wherein the etch-stop layer has a thickness of at least 1100 angstroms.

6. The method of claim 1, further comprising, prior to the cleaning:

applying a photoresist on the etch-stop layer;

patterning the photoresist; and

etching the etch-stop layer.

7. The method of claim 6, further comprising ashing the photoresist prior to the cleaning.

8. A method of making a semiconductor device, comprising:

forming a semiconductor structure by the method of claim 1, and

forming a semiconductor device from the semiconductor structure.

9. A method of making an electronic device, comprising:

forming a semiconductor device by the method of claim 8, and

forming an electronic device comprising the semiconductor device.

10. A method of making a semiconductor structure, comprising:

cleaning a gate stack comprising a metallic layer with a solution;

wherein the metallic layer is on a gate layer,

the gate layer is on a semiconductor substrate,

an etch-stop layer is on the metallic layer,

the metallic layer comprises tungsten and has a thickness of at most 450 angstroms, and

the cleaning solution consists essentially of;

(a) an amino alkoxy alcohol having 2-12 carbon atoms,

(b) an aromatic diol or triol, and

(c) hydroxylamine or an alkylhydroxylamine containing 1-6 carbon atoms.

11. The method of claim 10, wherein the gate is on an isolation region in the substrate, and the width of the isolation region under the gate is at most 0.4 microns.

12. The method of claim 10, wherein the cleaning solution consists essentially of 2-(2 aminoethoxy)ethanol, hydroxylamine, and catechol.

13. The method of claim 10, wherein the etch-stop layer has a thickness of at least 1100 angstroms.

14. The method of claim 10, further comprising, prior to the cleaning:

applying a photoresist on the etch-stop layer;

patterning the photoresist; and

etching the etch-stop layer.

15. The method of claim 14, further comprising ashing the photoresist prior to the cleaning.

16. A method of making a semiconductor structure, comprising:

removing photoresist;

wherein the photoresist is on a etch-stop layer,

the etch-stop layer is on a metallic layer,

the metallic layer has a thickness of at most 450 angstroms and is on a gate layer,

the gate layer is on a semiconductor substrate, and

the removing comprises ashing and applying a cleaning solution consisting essentially of;

(a) at least one member selected from the group consisting of an amino alcohol and amino ether,

(b) at least one member selected from the group consisting of an aromatic alcohol, aliphatic polyol, and aliphatic polyol ether, and

(c) a hydroxylamine.

17. The method of claim 16, wherein the cleaning solution consists essentially of:

(a) an amino alkoxy alcohol having 2-12 carbon atoms,

(b) an aromatic diol or triol, and

(c) hydroxylamine or an alkylhydroxylamine containing 1-6 carbon atoms.

18. The method of claim 16, wherein the cleaning solution consists essentially of 2-(2 aminoethoxy)ethanol, hydroxylamine, and catechol.

19. The method of claim 16, wherein the removing further comprises downstream plasma ashing.

20. The method of claim 16, further comprising, prior to the removing:

applying the photoresist on the etch-stop layer;

patterning the photoresist; and

etching the etch-stop layer.

21. The method of claim 16, wherein the gate comprises a P⁺ region and an N⁺ region.

22. The method of claim 16, wherein the etch-stop layer has a thickness of at least 1100 angstroms.