UV TREATMENT FOR CARBON-CONTAINING LOW-K DIELECTRIC REPAIR IN SEMICONDUCTOR PROCESSING
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.