Method of decreasing the K value in SiOC layer deposited by chemical vapor deposition

• US 6,627,532 B1
• Filed: 10/05/2000
• Issued: 09/30/2003
• Est. Priority Date: 02/11/1998
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Lu, Yung-Cheng, Xia, Li-Qun, Gaillard, Frederic, Yieh, Ellie, Jeng, Shin-Puu, Yau, Wai-Fan, Liu, Kuowei, Lim, Tian-Hoe
• Primary Examiner(s): Zarabian, Amir
• Assistant Examiner(s): VOCKRODT, JEFF B
• Application Number:
  US09/679,843
• Time in Patent Office: 1,090 Days
• Field of Search: 438/623, 438/624, 438/622, 438/637, 438/638, 438/763, 438/780, 438/781, 438/787, 438/788, 438/789
• US Class Current: 438/623
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02167 the material being a silicon carbide not containing oxygen, e.g. SiC, SiC:H or silicon carbonitrides H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02208 the precursor containing a compound comprising Si
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/02304 formation of intermediate layers, e.g. buffer layers, layers to improve adhesion, lattice match or diffusion barriers
• CPC Class Codes: H01L 21/02362 formation of intermediate layers, e.g. capping layers or diffusion barriers
• CPC Class Codes: H01L 21/314 Inorganic layers H01L21/3105, H01L21/32 take precedence
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: H01L 21/76801 characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing
• CPC Class Codes: H01L 21/7681 involving one or more buried masks
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors
• CPC Class Codes: H01L 21/76828 thermal treatment
• CPC Class Codes: H01L 21/76834 : formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence

Abstract

A method for processing a substrate comprising depositing a dielectric layer comprising silicon, oxygen, and carbon on the substrate by chemical vapor deposition, wherein the dielectric layer has a carbon content of at least 1% by atomic weight and a dielectric constant of less than about 3, and depositing a silicon and carbon containing layer on the dielectric layer. The dielectric constant of a dielectric layer deposited by reaction of an organosilicon compound having three or more methyl groups is significantly reduced by further depositing an amorphous hydrogenated silicon carbide layer by reaction of an alkylsilane in a plasma of a relatively inert gas.

Claims

1. A method for processing a substrate, comprising:

reacting an organosilicon compound including at least a structure of;

 

with an oxidizing gas selected from the group consisting of N₂O, O₂, O₃, and combinations thereof, to deposit a dielectric layer comprising silicon, oxygen, and carbon on the substrate, wherein the dielectric layer has a carbon content of at least 1% by atomic weight and a dielectric constant of less than about 3;

depositing a silicon and carbon containing layer on the dielectric layer; and

annealing the dielectric layer comprising silicon, oxygen, and carbon and the silicon and carbon containing layer.

2. The method of claim 1, wherein the organosilicon compound is selected from the group of trimethylsilane, 1,1,3,3-tetramethyldisiloxane, 2,2-bis (1-methyldisiloxanyl) propane, 1,3,5,7-tetramethylcyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclo-pentasiloxane, fluorinated carbon derivatives thereof, and combinations thereof.

3. The method of claim 1, wherein the organosilicon compound comprises three or more alkyl groups.

4. The method of claim 1, wherein the organosilicon compound comprises trimethylsilane and the oxidizing gas comprises ozone.

5. The method of claim 1, wherein the dielectric layer has a dielectric constant of about 3 or less.

6. A method for processing a substrate, comprising:

reacting an organosilicon compound comprising 1,3,5,7-tetramethylcyclotetrasiloxane with an oxidizing gas to deposit a dielectric layer comprising silicon, oxygen, and carbon on the substrate, wherein the dielectric layer has a carbon content of at least 1% by atomic weight and a dielectric constant of less than about 3;

depositing a silicon and carbon containing layer on the dielectric layer; and

annealing the dielectric layer comprising silicon, oxygen, and carbon and the silicon and carbon containing layer.

7. A method for processing a substrate, comprising:

reacting an organosilicon compound including at least a structure of;

 

with an oxidizing gas to deposit a dielectric layer comprising silicon, oxygen, and carbon on the substrate, wherein the dielectric layer has a carbon content of at least 1% by atomic weight and a dielectric constant of less than about 3;

depositing a silicon and carbon containing layer on the dielectric layer; and

annealing the dielectric layer comprising silicon, oxygen, and carbon and the silicon and carbon containing layer, wherein the dielectric constant of the dielectric layer is reduced by depositing the silicon and carbon containing layer.

8. A method for processing a substrate, comprising:

reacting an organosilicon compound including at least a structure of;

 

with an oxidizing gas to deposit a dielectric layer comprising silicon, oxygen, and carbon on the substrate, wherein the dielectric layer has a carbon content of at least 1% by atomic weight and a dielectric constant of less than about 3;

depositing a silicon and carbon containing layer on the dielectric layer; and

annealing the dielectric layer comprising silicon, oxygen, and carbon and the silicon and carbon containing layer, wherein the silicon and carbon containing layer is a silicon carbide layer deposited by introducing an alkylsilane compound and a relatively inert gas into a processing chamber and initiating a plasma, and the dielectric constant of the dielectric layer is reduced by depositing the silicon carbide layer.

9. The method of claim 8, wherein the alkylsilane compound is trimethylsilane.

10. The method of claim 8, wherein the plasma is generated by supplying a RF power density between about 4.3 watts per square centimeter and about 10.0 watts per square centimeter above the substrate.

11. A method for processing a substrate, comprising:

depositing a dielectric layer on the substrate by reacting an organosilicon compound and an oxidizing gas selected from the group consisting of N₂O, O₂, O₃, and combinations thereof, wherein the dielectric layer has a carbon content of at least 1% by atomic weight and a dielectric constant of less than about 3 and the organosilicon compound has a structure comprising at least;

reducing the dielectric constant of the dielectric layer by depositing a silicon carbide layer or a doped silicon carbide layer on the dielectric layer; and

annealing the dielectric layer comprising silicon, oxygen, and carbon and the silicon and carbon containing layer.

12. The method of claim 11, wherein the dielectric layer is deposited from an organosilicon compound selected from the group of trimethylsilane, 1,1,3,3-tetramethyldisiloxane, 2,2-bis(1-methyidisiloxanyl)propane, 1,3,5,7-tetramethylcyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclo-pentasiloxane, fluorinated carbon derivatives thereof, and combinations thereof.

13. The method of claim 11, wherein the organosilicon compound comprises three or more alkyl groups.

14. The method of claim 11, wherein the organosilicon compound comprises trimethylsilane and the oxidizing gas comprises ozone.

15. The method of claim 11, wherein the organosilicon compound comprises 1,3,5,7-tetramethylcyclotetrasiloxane.

16. The method of claim 11, wherein the dielectric layer has a carbon content between about 1% and about 50% by atomic weight prior to depositing the silicon carbide layer.

17. The method of claim 11, wherein the dielectric layer has a dielectric constant of about 3 or less prior to depositing the silicon carbide layer.

18. The method of claim 11, wherein the silicon carbide layer is deposited by introducing an alkylsilane compound and a relatively inert gas into a processing chamber and initiating a plasma.

19. The method of claim 18, wherein the alkylsilane compound is trimethylsilane.

20. The method of claim 18, wherein the dielectric constant of the dielectric layer is less than about 2.4 after depositing the silicon carbide layer.

21. The method of claim 18, wherein the plasma is generated by supplying a RF power density between about 4.3 watts per square centimeter and about 10.0 watts per square centimeter above the substrate.

22. The method of claim 18, wherein the silicon carbide layer is deposited at plasma conditions that remove carbon from the dielectric layer without reducing dielectric layer thickness.

23. A method for processing a substrate, comprising:

depositing a dielectric layer on the substrate by reacting an organosilane compound having three or more alkyl groups with ozone, wherein the dielectric layer has a carbon content between about 5% and about 50% by atomic weight and a dielectric constant less than about 3; and

depositing a silicon carbide layer or a doped silicon carbide layer on the dielectric layer by reacting an alkylsilane compound at plasma conditions sufficient to reduce the dielectric constant of the dielectric layer.

24. The method of claim 23, wherein the organosilicon compound is trimethylsilane and the alkylsilane compound is trimethylsilane.

25. The method of claim 23, wherein the organosilicon compound is 1,3,5,7-tetramethylcyclotetrasiloxane.

26. The method of claim 23, wherein the dielectric layer has a dielectric constant of about 2.4 or less after depositing the silicon carbide layer.

27. The method of claim 23, wherein the plasma is generated by supplying a RF power density between about 4.3 watts per square centimeter and about 10.0 watts per square centimeter above the substrate.