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

• US 20040029400A1
• Filed: 07/31/2003
• Published: 02/12/2004
• Est. Priority Date: 02/11/1998
• Status: Active Grant

• 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
• Granted Patent: US 6,784,119 B2
• Time in Patent Office: Days
• US Class Current: 438/778
• 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 selected from the group consisting of dimethylsilanediol, diphenylsilanediol, dimethyldimethoxysilane, diethyldiethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, 1,3-bis(silanomethylene)disiloxane, bis(1-methyldisiloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)propane, 1,3,5,7-tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclopentasiloxane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3,5-trisilanetetrahydropyran, and 2,5-disilanetetrahydrofuran to deposit a dielectric layer comprising silicon, oxygen, and carbon on the substrate; and

depositing a layer comprising silicon, carbon, and hydrogen on the dielectric layer.

2. The method of claim 1, wherein the organosilicon compound is octamethylcyclotetrasiloxane.

3. The method of claim 1, wherein the layer comprising silicon, carbon, and hydrogen is deposited from a gas mixture comprising a compound selected from the group consisting of methylsilane, dimethysilane, trimethylsilane, diethylsilane, propylsilane, vinylmethylsilane, 1,1,2,2-tetramethyldisilane, hexamethyldisilane, 1,1,2,2,3,3-hexamethyltrisilane, 1,1,2,3,3-pentamethyltrisilane, dimethyldisilanoethane, dimethyldisilanopropane, tetramethyldisilanoethane, and tetramethyldisilanopropane.

4. The method of claim 1, wherein the layer comprising silicon, carbon, and hydrogen further comprises a dopant and is deposited from a gas mixture comprising the dopant.

5. The method of claim 4, wherein the gas mixture further comprises a silicon source, and the ratio of the silicon source to the dopant in the gas mixture is between about 1:

1 to about 1;

100.

6. The method of claim 1, wherein the organosilicon compound is reacted in the absence of an oxidizer other than the organosilicon compound.

7. The method of claim 1, wherein the layer comprising silicon, carbon, and hydrogen is deposited by a plasma process.

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

9. A method for processing a substrate, comprising:

reacting a gas mixture comprising an organosilicon compound selected from the group consisting of methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, dimethylsilanediol, ethylsilane, phenylsilane, diphenylsilane, diphenylsilanediol, methylphenylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilanopropane, 1,3,5-trisilano-2,4,6-trimethylene, dimethyldimethoxysilane, diethyldiethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, 1,3-bis(silanomethylene)disiloxane, bis(1-methyldisiloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)propane, 1,3,5,7-tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclopentasiloxane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3,5-trisilanetetrahydropyran, and 2,5-disilanetetrahydrofuran, 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; and

depositing an oxygen doped silicon carbide layer on the dielectric layer by reacting an alkylsilane and oxygen in a plasma of an inert gas.

10. The method of claim 9, wherein the gas mixture further comprises an oxidizing gas.

11. The method of claim 10, wherein the oxidizing gas is selected from the group consisting of oxygen (O₂), ozone (O₃), nitrous oxide (N₂O), carbon monoxide (CO), carbon dioxide (CO₂), water (H₂O), and combinations thereof.

12. The method of claim 9, wherein the alkylsilane is selected from the group consisting of methylsilane, dimethysilane, trimethylsilane, diethylsilane, propylsilane, vinylmethylsilane, 1,1,2,2-tetramethyldisilane, hexamethyldisilane, 1,1,2,2,3,3-hexamethyltrisilane, 1,1,2,3,3-pentamethyltrisilane, dimethyldisilanoethane, dimethyldisilanopropane, tetramethyldisilanoethane, and tetramethyldisilanopropane.

13. The method of claim 9, wherein the inert gas is selected from the group consisting of helium, argon, and nitrogen.

14. The method of claim 9, wherein the plasma is formed at between about 0.3 W/cm² and about 3.2 W/cm².

15. A method for processing a substrate, comprising:

reacting an organosilicon compound selected from the group consisting of dimethylsilanediol, diphenylsilanediol, dimethyldimethoxysilane, diethyldiethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, 1,3-bis(silanomethylene)disiloxane, bis(1-methyldisiloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)propane, 1,3,5,7-tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclopentasiloxane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3,5-trisilanetetrahydropyran, and 2,5-disilanetetrahydrofuran to deposit a dielectric layer comprising silicon, oxygen, and carbon on the substrate; and

depositing an oxygen doped silicon carbide layer on the dielectric layer.

16. The method of claim 15, wherein the organosilicon compound is octamethylcyclotetrasiloxane.

17. The method of claim 15, wherein the oxygen doped silicon carbide layer is deposited from a gas mixture comprising oxygen and a compound selected from the group consisting of methylsilane, dimethysilane, trimethylsilane, diethylsilane, propylsilane, vinylmethylsilane, 1,1,2,2-tetramethyldisilane, hexamethyldisilane, 1,1,2,2,3,3-hexamethyltrisilane, 1,1,2,3,3-pentamethyltrisilane, dimethyldisilanoethane, dimethyldisilanopropane, tetramethyldisilanoethane, and tetramethyldisilanopropane.

18. The method of claim 15, wherein the organosilicon compound is reacted in the absence of an oxidizer other than the organosilicon compound.

19. The method of claim 15, the oxygen doped silicon carbide layer is deposited by a plasma process.

20. The method of claim 15, wherein the dielectric layer has a dielectric constant of about 3 or less.