Removal of surface passivation
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.
1. A method of removing copper-containing particles from a dielectric substrate surface, comprising:
contacting the dielectric substrate surface comprising copper-containing particles with a vapor phase organic reactant in a plurality of cycles without exposing the substrate to a plasma, such that copper-containing particles are removed from the surface, and
wherein the vapor phase organic reactant interacts with the copper-containing particles to reduce a size of the copper-containing particles.
2. The method of claim 1 , wherein the copper-containing particles are removed from a substrate surface that does not otherwise comprise copper.
3. The method of claim 1 , wherein the copper-containing particles are removed from a dielectric surface of the substrate.
4. The method of claim 1 , wherein the vapor phase organic reactant interacts with the copper-containing particles to form one or more volatile byproducts.
5. The method of claim 1 , wherein the vapor phase organic reactant is an alcohol, an aldehyde, or has the formula R—COOH, where R is hydrogen or a C1 to C3 alkyl.
6. The method of claim 1 , wherein the vapor phase organic reactant comprises a carboxylic acid.
7. The method of claim 1 , wherein the vapor phase organic reactant comprises formic acid.
8. The method of claim 1 , wherein the substrate surface is contacted with the vapor phase organic reactant at a temperature of 100° C. to 400° C.
9. The method of claim 1 , wherein greater than 70% of the copper-containing particles that were present on the substrate surface are removed from the substrate surface when the substrate surface comprising copper-containing particles is contacted with the vapor phase organic reactant.
10. The method of claim 1 , wherein the copper-containing particles have a longest dimension of up to 20 nm.
11. The method of claim 1 , wherein the copper-containing particles form a passivation layer on the substrate surface prior to contacting the substrate surface with the vapor-phase organic reactant.
12. The method of claim 1 , wherein the substrate comprises a copper surface that has been subject to chemical mechanical polishing prior to contacting the substrate surface with the vapor phase organic reactant.
13. The method of claim 12 , wherein the chemical mechanical polishing comprises exposing the copper surface to benzotriazole.
14. A method for removing at least a portion of a passivation film comprising copper particles from a dielectric substrate surface, the method comprising:
exposing the passivation film to a vapor phase organic reactant in a plurality of cycles, wherein the vapor phase organic reactant is an alcohol, an aldehyde or has the formula R—COOH, where R is hydrogen or a C1 to C3 alkyl,
wherein the passivation film was formed on the dielectric substrate surface by subjecting a copper surface on the substrate to chemical mechanical polishing, and
wherein the passivation film is not exposed to a plasma during exposure of the passivation film to the vapor phase organic reactant.
15. The method of claim 14 , wherein the passivation film is exposed to the vapor phase organic reactant at a temperature of 100° C. to 400° C.
16. The method of claim 14 , wherein the vapor phase organic reactant comprises carboxylic acid.
17. The method of claim 14 , wherein the vapor phase organic reactant comprises formic acid.
18. The method of claim 14 , wherein the passivation film is exposed to the vapor phase organic reactant at least 10 times.
19. The method of claim 14 , wherein chemical mechanical polishing comprises exposing the copper surface to benzotriazole.