Repair of carbon depletion in low-k dielectric films
View Patent ↗A method of repairing damaged low-k dielectric materials is disclosed. Plasma-based processes, which are commonly used in semiconductor device manufacturing, frequently damage carbon-containing, low-k dielectric materials. Upon exposure to moisture, the damaged dielectric material may form silanol groups. In preferred embodiments, a two-step approach converts the silanol to a suitable organic group. The first step includes using a halogenating reagent to convert the silanol to a silicon halide. The second step includes using a derivatization reagent, preferably an organometallic compound, to replace the halide with the suitable organic group. In a preferred embodiment, the halogenating agent includes thionyl chloride and the organometallic compound includes an alkyllithium, preferably methyllithium. In another preferred embodiment, the organometallic compound comprises a Grignard reagent. Embodiments disclosed herein advantageously enable the manufacturer to engineer the density, polarization, and ionization properties of the low-k dielectric material by selective incorporation of the organic group.
1. A method of fabricating a semiconductor device comprising:
forming an active device on a substrate;
depositing a carbon-containing, low-k insulator over the active device;
exposing the insulator to a plasma;
forming a silicon halide by reacting a silanol in the insulator with a halogenating agent; and
performing a derivatizing reaction with the silicon halide.
2. The method of claim 1 , wherein the low-k insulator comprises a carbon-doped oxide.
3. The method of claim 1 , wherein the low-k insulator comprises porous silica.
4. The method of claim 1 , wherein the low-k insulator comprises OSG.
5. The method of claim 1 , wherein the halogenating agent is selected from the group consisting essentially of thionyl chloride, sulfuryl chloride and carboxydichloride.
6. The method of claim 1 , wherein the halogenating agent is selected from the group consisting essentially of a chloride compound, a bromide compound, and an iodide compound, or a combination thereof.
7. The method of claim 1 , wherein the derivatizing reaction includes using an organometallic compound.
8. The method of claim 7 , wherein the organometallic compound is a Grignard reagent.
9. The method of claim 7 , wherein the organometallic compound is lithium dialkylcopper.
10. The method of claim 7 , wherein the organometailic compound is trimethyl aluminum.
11. The method of claim 7 , wherein the organometallic compound is methyl lithium.
12. The method of claim 1 , wherein the derivatizing reaction includes using a compound corresponding to the general formula R A R B R C C(R D X):
wherein R A , R B , R C , and R D are independently hydrogen or an alkyl group; and
X is selected from the group consisting of Br, I, O-alkyl, O-fluorosulfonate, and O-triflate.
13. The method of claim 1 , wherein the derivatizing reaction includes using a compound corresponding to the general formula R A R B R C CX:
wherein R A , R B , and R C are independently hydrogen or an alkyl group; and
X is selected from the group consisting of Br, I, O-alkyl, O-fluorosulfonate, and O-triflate.
14. The method of claim 1 , wherein the derivatizing reaction includes using a compound corresponding to the general formula R A R B C═CHR C , wherein R A-C are independently hydrogen or an alkyl group.
15. The method of claim 14 , wherein the derivatizing reaction further includes using a Lewis acid.
16. The method of claim 1 , wherein the derivatizing reaction includes using a silylation agent.
17. The method of claim 16 , wherein the silylation agent corresponds to the general formula R A R B R C Si(R D X):
wherein R A , R B , R C , and R D are independently hydrogen or an alkyl group; and
X is selected from the group consisting of Br, I, O-alkyl, O-fluorosulfonate, and O-triflate.
18. The method of claim 16 , wherein the silylation agent corresponds to the general formula R A R B R C SiX:
wherein R A , R B , and R C , are independently alkyl, aryl, or hydrogen; and
X is selected from the group consisting of Br, I, O-alkyl, O-fluorosulfonate, and O-triflate.
19. A method of fabricating a semiconductor device comprising:
depositing a carbon-containing dielectric on an active device;
halogenating the carbon-containing dielectric; and
derivatizing the carbon-containing dielectric after halogenating.
20. The method of claim 19 , further comprising exposing the carbon-containing dielectric to a plasma.
21. The method of claim 20 , wherein the carbon-containing dielectric further comprises an organosilicate glass.
22. The method of claim 19 , wherein halogenating the carbon-containing dielectric further comprises using thionyl chloride, sulfuryl chloride, or carboxydichloride.
23. The method of claim 19 , wherein derivatizing the carbon-containing dielectric after halogenating further comprises using an alkyl lithium compound or a Grignard reagent.
24. The method of claim 19 , wherein derivatizing the carbon-containing dielectric after halogenating further comprises using a compound corresponding to the general formula R A R B R C Si(R D X) or R A R B R C C(R D X):
wherein R A , R B , R C , and R D are independently hydrogen or an alkyl group; and
X is selected from the group consisting of Br, I, O-alkyl, O-fluorosulfonate, and O-triflate.