Method of repairing a low dielectric constant material layer

• US 6,521,547 B1
• Filed: 09/07/2001
• Issued: 02/18/2003
• Est. Priority Date: 09/07/2001
• Status: Active Grant

• Current Assignee: Marlin Semiconductor Limited (f/k/a Sandyford Semiconductor Limited) (Vector Capital Corporation)
• Original Assignee: United Microelectronics Corporation
• Inventors: Chang, Ting-Chang, Mor, Yi-Shien, Liu, Po-Tsun
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): Nhu, David
• Application Number:
  US09/682,479
• Time in Patent Office: 529 Days
• Field of Search: 438/637, 438/680, 438/689, 438/706, 438/745, 438/780, 438/781, 438/789, 438/790
• US Class Current: 438/781
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/31058 of organic layers
• CPC Class Codes: H01L 21/31138 by dry-etching
• CPC Class Codes: H01L 21/76802 by forming openings in dielectrics

Abstract

A method of repairing a low dielectric constant (low k) material layer starts with coating a photoresist layer on the low k material layer on a semiconductor wafer. After transferring a pattern of the photoresist layer to the low k material layer, an oxygen plasma ashing process is performed to remove the photoresist layer. Finally, by contacting the low k material layer with a solution of alkyl silane comprising an alkyl group and halo substituent, Si—OH bonds formed in the low k layer during the oxygen plasma ashing process are removed so as to repair damage to the low k material layer caused by the oxygen plasma ashing process, and to enhance a surface of the low k material layer to a hydrophobic surface to prevent moisture adhering to the surface of the low k material layer.

Claims

1. A method of repairing a low dielectric constant (low k) material layer, the method comprising:

providing a semiconductor wafer with a low k material layer;

coating a photoresist layer on the low k material layer;

forming an opening to expose a portion of the low k material layer;

dry etching the low k material layer through the opening to transfer a pattern in the photoresist layer to the low k material layer;

performing an oxygen plasma ashing process to remove the photoresist layer; and

contacting the low k material layer with a hexane solution of alkyl silane comprising an alkyl group and halo substituent;

wherein the hexane solution of alkyl silane comprising the alkyl group and halo substituent is employed to remove Si—

OH bonds formed in the low k layer during the oxygen plasma ashing process to repair damage to the low k material layer caused by the oxygen plasma ashing process, and to enhance a surface of the low k material layer to a hydrophobic surface to prevent moisture adhering to the surface of the low k material layer.

2. The method of claim 1 wherein the low k material layer is a silicon oxide based (SiO₂-based) low k material layer.

3. The method of claim 1 wherein the low k material layer comprises hydrogen silsesquioxane (HSQ), methyl silsesquioxane (MSQ), hybrid-organic-siloxane-polymer (HOSP), or sol-gel.

4. The method of claim 1 wherein a hydrogen plasma pretreatment is performed on the low k material layer before coating the photoresist layer on the low k material layer.

5. The method of claim 1 wherein the alkyl silane comprising the alkyl group and halo substituent is an alkyl silane comprising a mono-halo substituent.

6. The method of claim 5 wherein the alkyl silane comprising the alkyl group and halo substituent is composed of trimethylchlorosilane (Si(CH₃)₃Cl), dimethylchlorosilane (Si(CH₃)₂HCl), ethylchlorosilane (Si(C₂H₅)H₂Cl), propylchlorosilane (Si(C₃H₇)H₂Cl), ethylbromosilane (Si(C₂H₅)H₂Br), or propylbromosilane (Si(C₃H₇)H₂Br).

7. The method of claim 1 wherein the hexane solution of alkyl silane comprising the alkyl group and halo substituent is a hexane solution with trimethylchlorosilane (TMCS) of a volumetric concentration that is less than 8%.

8. A method of repairing a low dielectric constant (low k) material layer, the method comprising:

providing a semiconductor wafer with a low k material layer;

coating a photoresist layer on the low k material layer;

forming an opening to expose a portion of the low k material layer;

dry etching the low k material layer through the opening to transfer a pattern in the photoresist layer to the low k material layer;

performing a photoresist ashing process to remove the photoresist layer; and

performing at least one surface repairing process to contact the low k material layer with a hexane solution of alkyl silane comprising an alkyl group and halo substituent;

wherein the hexane solution of alkyl silane comprising the alkyl group and halo substituent is employed to remove Si—

OH bonds formed in the low k layer during the photoresist ashing process, to repair the damage of the low k material layer caused by the photoresist ashing process, and to enhance a surface of the low k material layer to a hydrophobic surface.

9. The method of claim 8 wherein the low k material layer comprises hydrogen silsesquioxane (HSQ), methyl silsesquioxane (MSQ), hybrid-organic-siloxane-polymer (HOSP), or sol-gel.

10. The method of claim 8 wherein the photoresist ashing process is performed with an oxygen plasma supply.

11. The method of claim 8 wherein the photoresist ashing process is performed with an ozone plasma supply.

12. The method of claim 8 wherein a hydrogen plasma pretreatment is performed on the low k material layer before coating the photoresist layer on the low k material layer.

13. The method of claim 8 wherein the hexane solution of alkyl silane comprising the alkyl group and halo substituent is a hexane solution with trimethylchlorosilane (TMCS) of a volumetric concentration that is less than 8%.

14. The method of claim 8 wherein the alkyl silane comprising the alkyl group and halo substituent is a liquid phase alkyl silane comprising the alkyl group and halo substituent.

15. The method of claim 8 wherein the alkyl silane comprising the alkyl group and halo substituent is an alkyl silane comprising a mono-halo substituent.

16. The method of claim 15 wherein the alkyl silane comprising the alkyl group and halo substituent is composed of trimethylchlorosilane (Si(CH₃)₃Cl), dimethylchlorosilane (Si(CH₃)₂HCl), ethylchlorosilane (Si(C₂H₅)H₂Cl), propylchlorosilane (Si(C₃H₇)H₂Cl), ethylbromosilane (Si(C₂H₅)H₂Br) or propylbromosilane (Si(C₃H₇)H₂Br).