Uv treatment for carbon-containing low-k dielectric repair in semiconductor processing

Abstract

A method for the ultraviolet (UV) treatment of carbon-containing low-k dielectric enables process-induced damage repair. The method is particularly applicable in the context of damascene processing. A method provides for forming a semiconductor device by depositing a carbon-containing low-k dielectric layer on a substrate and forming a trench in the low-k dielectric layer, the trench having sidewalls ending at a bottom. The trench is then exposed to UV radiation and, optionally a gas phase source of —CH 3 groups, to repair damage to the carbon-containing low-k material of the trench sidewalls and bottom caused by the trench formation process (generally etching, ashing, and wet or dry cleaning). A similar treatment, with or without the gas phase source of —CH 3 groups, may be applied to repair damage caused in a subsequent planarization operation.

1 . A method of forming a semiconductor device in damascene processing, comprising:
 receiving in a processing chamber a semiconductor device substrate comprising a planarized surface having conductive features in a carbon-containing low-k dielectric layer;   exposing the planarized surface to UV radiation;   whereby planarization-induced low-k dielectric damage on the surface is repaired without substantially altering the dielectric properties.   
     
     
         2 . The method of  claim 1 , wherein the conductive features are comprised of metal. 
     
     
         3 . The method of  claim 2 , wherein oxide is removed from the metal surface. 
     
     
         4 . The method of  claim 1 , further comprising exposing the planarized surface to a gas phase source of —CH 3  groups. 
     
     
         5 . The method of  claim 4 , wherein the gas phase source of —CH 3  groups comprises one or more selected from the group consisting of organo-silanes, -silazanes, and -siloxanes; acetaldehyde; alkanes; alkenes; and alkynes. 
     
     
         6 . The method of  claim 5 , wherein the gas phase source of —CH 3  groups comprises one or more selected from the group consisting of dichlorodimethylsilane (DCDMS), chlorotrimethylsilane (CTMS), hexamethyldisilazane (HMDS), hexamethyldisiloxane (HMDSO), tetravinyltetramethylcyclotetrasiloxane (TVTMCTS), acetaldehyde, methane, ethane, ethylene, acetylene, and combinations thereof. 
     
     
         7 . The method of  claim 6 , wherein the gas phase source of —CH 3  groups comprises one or more selected from the group consisting of dichlorodimethylsilane (DCDMS), chlorotrimethylsilane (CTMS), hexamethyldisilazane (HMDS), hexamethyldisiloxane (HMDSO), tetravinyltetramethylcyclotetrasiloxane (TVTMCTS), and combinations thereof. 
     
     
         8 . The method of  claim 2 , wherein the metal is copper. 
     
     
         9 . The method of  claim 1 , wherein the UV radiation has a power density of about 500 mW-5 W/cm 2  and a wavelength from about 150-500 nm, and the exposure is conducted at a temperature of about room temperature up to 450° C. for less than 20 minutes. 
     
     
         10 . The method of  claim 1 , wherein the UV radiation has a power density of about 1-3 W/cm 2  and a wavelength from about 200-400 nm, and the exposure is conducted at a temperature of about 200-400° C. for less than 5 minutes. 
     
     
         11 . The method of  claim 1 , wherein the carbon-containing low-k dielectric comprises CDO. 
     
     
         12 . A method of forming a semiconductor device, comprising:
 receiving in a processing chamber a semiconductor device substrate comprising a carbon-containing low-k dielectric layer, the semiconductor device substrate having been damaged by a semiconductor processing operation;   exposing the low-k dielectric layer to UV radiation such that processing-induced low-k dielectric damage to the dielectric is repaired without substantially altering the dielectric properties.   
     
     
         13 . The method of  claim 12 , further comprising exposing the low-k dielectric layer to a gas phase source of —CH 3  groups. 
     
     
         14 . The method of  claim 13 , wherein the gas phase source of —CH 3  groups comprises one or more selected from the group consisting of organo-silanes, -silazanes, and -siloxanes; acetaldehyde; alkanes; alkenes; and alkynes. 
     
     
         15 . The method of  claim 14 , wherein the gas phase source of —CH 3  groups comprises one or more selected from the group consisting of dichlorodimethylsilane (DCDMS), chlorotrimethylsilane (CTMS), hexamethyldisilazane (HMDS), hexamethyldisiloxane (HMDSO), tetravinyltetramethylcyclotetrasiloxane (TVTMCTS), acetaldehyde, methane, ethane, ethylene, acetylene, and combinations thereof. 
     
     
         16 . The method of  claim 15 , wherein the gas phase source of —CH 3  groups comprises one or more selected from the group consisting of dichlorodimethylsilane (DCDMS), chlorotrimethylsilane (CTMS), hexamethyldisilazane (HMDS), hexamethyldisiloxane (HMDSO), tetravinyltetramethylcyclotetrasiloxane (TVTMCTS), and combinations thereof. 
     
     
         17 . The method of  claim 12 , wherein the UV radiation has a power density of about 500 mW-5 W/cm 2  and a wavelength from about 150-500 nm, and the exposure is conducted at a temperature of about room temperature up to 450° C. for less than 20 minutes. 
     
     
         18 . The method of  claim 12 , wherein the UV radiation has a power density of about 1-3 W/cm 2  and a wavelength from about 200-400 nm, and the exposure is conducted at a temperature of about 200-400° C. for less than 5 minutes. 
     
     
         19 . The method of  claim 12 , wherein the carbon-containing low-k dielectric comprises CDO. 
     
     
         20 . The method of  claim 12 , where the device substrate further comprises metal features.