Removal of surface passivation

• US 9,490,145 B2
• Filed: 02/23/2015
• Issued: 11/08/2016
• Est. Priority Date: 02/23/2015
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Niskanen, Antti Juhani, Anttila, Jaakko
• Primary Examiner(s): Lee, Cheung
• Application Number:
  US14/628,799
• Publication Number:
  US 20160247695A1
• Time in Patent Office: 624 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02074 the processing being a planarization of conductive layers
• CPC Class Codes: H01L 21/02225 characterised by the process for the formation of the insulating layer
• CPC Class Codes: H01L 21/02334 in-situ cleaning after layer formation, e.g. removing process residues
• CPC Class Codes: H01L 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/30621 Vapour phase etching
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/32135 by vapour etching only
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 21/76883 Post-treatment or after-treatment of the conductive material

Abstract

Methods for removing a passivation film from a copper surface can include exposing the passivation film to a vapor phase organic reactant, for example at a temperature of 100° C. to 400° C. In some embodiments, the passivation film may have been formed by exposure of the copper surface to benzotriazole, such as can occur during a chemical mechanical planarization process. The methods can be performed as part of a process for integrated circuit fabrication. A second material can be selectively deposited on the cleaned copper surface relative to another surface of the substrate.

Claims

1. A method for removing a passivation film from a substrate, the method comprising:

providing the substrate comprising a passivation film on a metal surface, wherein the passivation film was formed by exposure of the metal surface to a passivation agent comprising a hydrocarbon; and

exposing the passivation film to a vapor phase organic reactant at a temperature of 100°

C. to 400°

C., wherein the passivation film is not exposed to a plasma during exposure of the passivation film to the vapor phase organic reactant.

2. The method of claim 1, wherein the vapor phase organic reactant comprises carboxylic acid.

3. The method of claim 1, wherein the vapor phase organic reactant comprises formic acid.

4. The method of claim 1, wherein the passivation agent comprises an aromatic hydrocarbon.

5. The method of claim 1, wherein the passivation agent comprises benzotriazole.

6. The method of claim 1, further comprising repeating exposing the passivation film to the vapor phase organic reactant at least 10 times.

7. The method of claim 1, wherein the metal surface is a copper surface.

8. The method of claim 1, wherein the substrate further comprises a dielectric material, and wherein a surface chemistry of the dielectric material is substantially unaffected by exposing the passivation film to the vapor phase organic reactant.

9. A method for integrated circuit fabrication, comprising:

providing a substrate comprising a passivation film on a copper surface that was subjected to a chemical mechanical planarization process;

performing a cleaning process for removing the passivation film from the copper surface, wherein performing the cleaning process comprises;

contacting the passivation film with a vapor phase organic reactant at a process temperature of 100°

C. to 400°

C.,

wherein the vapor phase organic reactant has the formula R—

COOH, the R being a hydrogen, or a C₁-C₃ alkyl, and

wherein the cleaning process is substantially free of plasma activated reactants.

10. The method of claim 9, wherein during the chemical mechanical planarization process the copper surface was exposed to benzotriazole.

11. The method of claim 9, wherein the vapor phase organic reactant comprises formic acid.

12. The method of claim 9, wherein the substrate further comprises a dielectric material, and wherein a surface chemistry of the dielectric material is substantially unaffected by the cleaning process.

13. The method of claim 9, wherein the process temperature is 200°

C. to 250°

C.

14. A method of integrated circuit fabrication, comprising:

cleaning a copper surface of a substrate by removing a passivation film that was formed on the copper surface by exposure to a hydrocarbon passivation agent,

wherein cleaning comprises contacting the passivation film with a vapor phase organic reactant substantially without exposing the substrate to a plasma; and

selectively depositing a second material on the cleaned copper surface relative to a second surface on the substrate.

15. The method of claim 14, wherein the passivation agent comprises benzotriazole and the vapor phase organic reactant comprises a carboxylic acid.

16. The method of claim 14, wherein the passivation film comprises a coordination complex formed by the copper and the passivation agent.

17. The method of claim 14, wherein the passivation film is removed at a process temperature of 100°

C. to 400°

C.

18. The method of claim 14, wherein the second material comprises an electrically conductive material.

19. The method of claim 18, wherein the second material comprises tungsten.

20. The method of claim 14, wherein the second material comprises an electrically insulating material.

21. The method of claim 14, wherein the second surface comprises a dielectric material, and wherein the second material is substantially not deposited on the dielectric material.