Method of improving moisture resistance of low dielectric constant films

• US 6,245,690 B1
• Filed: 11/04/1998
• Issued: 06/12/2001
• Est. Priority Date: 11/04/1998
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Lu, Yung-Cheng, Yau, Wai-Fan, Moghadam, Farhad, Chopra, Nasreen Gazala, Mandal, Robert, Cheung, David
• Primary Examiner(s): MEEKS, TIMOTHY HOWARD
• Application Number:
  US09/187,460
• Time in Patent Office: 951 Days
• Field of Search: 427/376.2, 427/387, 427/489, 427/492, 427/497, 427/503, 427/509, 427/515, 427/577, 427/578, 427/579, 427/249.15, 427/255.37, 427/255.6, 438/780, 438/781, 438/789, 438/790
• US Class Current: 438/780
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/56 After-treatment
• 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 21/02164 the material being a silicon oxide, e.g. SiO2
• 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 21/02211 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 21/02282 liquid deposition, e.g. spin-coating, sol-gel techniques, spray coating
• 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 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/02343 treatment by exposure to a liquid
• CPC Class Codes: H01L 21/02359 treatment to change the surface groups of the insulating layer
• CPC Class Codes: H01L 21/3125 layers comprising silazane compounds
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: H01L 21/76807 for dual damascene structures

Abstract

A method and apparatus for depositing a low dielectric constant film includes depositing a silicon oxide based film, preferably by reaction of an organosilicon compound and an oxidizing gas at a low RF power level from about 10 W to about 500 W, exposing the silicon oxide based film to water or a hydrophobic-imparting surfactant such as hexamethyldisilazane, and curing the silicon oxide based film at an elevated temperature. Dissociation of the oxidizing gas can be increased in a separate microwave chamber to assist in controlling the carbon content of the deposited film. The moisture resistance of the silicon oxide based films is enhanced.

Claims

1. A method for depositing a low dielectric constant film, comprising:

depositing a silicon oxide based film comprising carbon-silicon bonds and a carbon content of between about 1% and about 50% by atomic weight on a substrate wherein the silicon oxide based film is located between conductive interconnects or conductive contacts/vias;

exposing the silicon oxide based film to a hydrophobic-imparting surfactant; and

then

curing the silicon oxide based film.

2. The method of claim 1, wherein the silicon oxide based film is deposited by reacting one or more silicon compounds that contain carbon with an oxidizing gas at an RF power level between about 10 W and about 500 W.

3. The method of claim 1, wherein the one or more silicon compounds are selected from the group consisting of methylsilane, dimethylsilane, trimethylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilano-propane, 1,3,5-trisilano-2,4,6-trimethylene, 1,3-dimethyldisiloxane, 1,3-bis(silanomethylene)disiloxane, bis(1-methyldisiloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)-propane, 2,4,6,8-tetramethyl-cyclotetrasiloxane, 2,4,6,8,10-pentamethylcyclopentasiloxane, 1,3,5,7-tetrasilano-2,6-dioxy4,8-dimethylene, fluorinated carbon derivatives thereof, and combinations thereof.

4. The method of claim 1, wherein the hydrophobic-imparting surfactant is selected from the group consisting of hexamethyldisilazane, trimethyl-silyldiethylamine, phenyldimethylsilyldimethylamine, trimethoxysilyldimethylamine, tris(trifluoromethyl)-silyldimethylamine, bis(trimethyl-silyl)hydrazine, 1-phenyldimethyl-silyl-2-methyl-hydrazine, 1-trimethoxysilyl-2-methyl-hydrazine, 1-tris(trifluoromethyl-silyl)-2-methyl-hydrazine, trimethylchlorosilane, and combinations thereof, and the silicon oxide based film is cured at a temperature between about 100°

C. and about 450°

C.

5. The method of claim 4, wherein the silicon oxide-based film is cured at a temperature at or above about 400°

C.

6. The method of claim 1, wherein the silicon oxide based film has a carbon content between about 5% and about 30% by atomic weight.

7. The method of claim 1, wherein the silicon oxide-based film is exposed to the hydrophobic-imparting surfactant and heated to a temperature between about 10°

C. and about 100°

C.

8. The method of claim 1, wherein the oxidizing gas is N₂O or O₂.

9. The method of claim 1, wherein the silicon oxide based film is deposited at a chamber pressure from about 0.2 Torr to about 2 Torr.

10. The method of claim 1, wherein the silicon oxide based film is deposited at a substrate temperature from about −

20°

C. to about 400°

C.

11. The method of claim 1, wherein the silicon oxide based film has a dielectric constant of about 3 or less.

12. A method for depositing a low dielectric constant film, comprising:

depositing a silicon oxide based film comprising carbon-silicon bonds and a carbon content of between about 1% and about 50% by atomic weight on a substrate by reacting one or more silicon compounds that contain carbon with an oxidizing gas at an RF power level between about 10 W and about 250 W, wherein the silicon oxide based film is located between conductive interconnects or conductive contacts/vias;

exposing the silicon oxide-based film to a hydrophobic-imparting surfactant and heating the silicon oxide-based film to a temperature between about 10°

C. and about 100°

C.; and

then

curing the silicon oxide based film at a temperature between about 100°

C. and about 400°

C.

13. The method of claim 12, wherein the one or more silicon compounds are selected from the group consisting of methylsilane, dimethylsilane, trimethylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilanopropane, 1,3,5-trisilano-2,4,6-trimethylene, 1,3-dimethyldisiloxane, 1,3-bis(silanomethylene)disiloxane, bis(1-methyldi-siloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)propane, 2,4,6,8-tetra-methylcyclotetra-siloxane, 2,4,6,8,10-pentamethylcyclopentasiloxane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, fluorinated carbon derivatives thereof, and combinations thereof.

14. The method process of claim 12, wherein the hydrophobic-imparting surfactant is selected from the group consisting of hexamethyldisilazane, trimethylsilyldiethylamine, phenyldimethylsilyldimethylamine, trimethoxysilyldimethylamine, tris(trifluoromethyl)-silyldimethylamine, bis(trimethyl-silyl)hydrazine, 1-phenyldimethylsilyl-2-methyl-hydrazine, 1-trimethoxysilyl-2-methyl-hydrazine, 1-tris(trifluoromethylsilyl)-2-methyl-hydrazine, trimethylchlorosilane and combinations thereof.

15. The method of claim 14, wherein the hydrophobic-imparting surfactant is hexamethyldisilazane.

16. The method of claim 12, wherein the silicon oxide based film has a carbon content between about 5% and 30% by atomic weight.

17. The method of claim 12, wherein the oxidizing gas is N₂O or O₂.

18. The method of claim 12, wherein the silicon oxide based film is deposited at a chamber pressure of between about 0.2 Torr and about 2 Torr.

19. The method of claim 12, wherein the silicon oxide based film is deposited at a substrate temperature of between about −

20°

C. and about 400°

C.

20. The method of claim 12, wherein the silicon oxide based film has a dielectric constant of about 3 or less.