Deposition-plasma cure cycle process to enhance film quality of silicon dioxide

• US 7,902,080 B2
• Filed: 05/25/2007
• Issued: 03/08/2011
• Est. Priority Date: 05/30/2006
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Chen, Xiaolin, Nemani, Srinivas D., Venkataraman, Shankar
• Primary Examiner(s): Vinh; Lan
• Application Number:
  US11/753,968
• Publication Number:
  US 20070281448A1
• Time in Patent Office: 1,383 Days
• Field of Search: 438/706, 438/713, 438/725, 438/714, 438/743, 438/710, 438/723, 216/58, 216/80
• US Class Current: 438/723
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/402 Silicon dioxide
• 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 21/02216 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 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC

Abstract

Methods of filling a gap on a substrate with silicon oxide are described. The methods may include the steps of introducing an organo-silicon precursor and an oxygen precursor to a deposition chamber, reacting the precursors to form a first silicon oxide layer in the gap on the substrate, and etching the first silicon oxide layer to reduce the carbon content in the layer. The methods may also include forming a second silicon oxide layer on the first layer, and etching the second layer to reduce the carbon content in the second layer. The silicon oxide layers are annealed after the gap is filled.

Claims

1. A method of filling a gap on a substrate with silicon oxide, the method comprising:

introducing an organo-silicon precursor and an oxygen precursor to a deposition chamber;

reacting the precursors to form a first silicon oxide layer in the gap on the substrate;

etching the first silicon oxide layer to reduce the carbon content in the layer;

forming a second silicon oxide layer on the first layer, and etching the second layer to reduce the carbon content in the layer, wherein the etching operation of the first and second silicon oxide layers comprises;

exposing the layer to a first plasma having a first density, wherein the first plasma dissociates larger carbon molecules in the layer, and

exposing the layer to a second plasma having a second density that is higher than the first density, wherein the second plasma dissociates silicon-hydroxide bonds in the layer; and

annealing the silicon oxide layers after the gap is filled.

2. The method of claim 1, wherein the organo-silicon precursor comprises dimethylsilane, trimethylsilane, tetramethylsilane, diethylsilane, tetramethylorthosilicate (TMOS), tetraethylorthosilicate (TEOS), octamethyltrisiloxane (OMTS), octamethylcyclotetrasiloxane (OMCTS), tetramethylcyclotetrasiloxane (TOMCATS), DMDMOS, DEMS, methyl triethoxysilane (MTES), phenyldimethylsilane, or phenylsilane.

3. The method of claim 1, wherein the first and second silicon oxide layers each have a thickness from about 100 Å

to about 200 Å

.

4. The method of claim 1, wherein the annealed silicon oxide layers have a wet etch rate ratio (WERR) of about 2:

1 or less.

5. The method of claim 1, wherein the annealed silicon oxide layers have a wet etch rate ratio (WERR) of about 1.8:

1 to about 1.4;

1.

6. The method of claim 1, wherein the annealed silicon oxide layers have a k-value of about 4.0 or less.

7. The method of claim 1, wherein the method further comprises pretreating the substrate with a high-density plasma before introducing the precursors to the deposition chamber.

8. The method of claim 1, wherein the gap has a height to width aspect ratio of about 5:

1 or more.

9. The method of claim 1, wherein the gap has a height to width aspect ratio of about 13:

1 or more.

10. The method of claim 1, wherein the annealing of the silicon oxide layers comprises an anneal in a dry non-reactive gas at a temperature of about 800°

C. or more.

11. The method of claim 10, wherein the non-reactive gas is nitrogen (N₂) and the temperature is 900°

C.

12. The method of claim 1, wherein the method includes forming additional silicon oxide layers on the first and second layers, and wherein each additional silicon oxide layer has a thickness of about 50 Å

to about 500 Å

.

13. The method of claim 12, wherein the additional silicon oxide layers are etched in the same manner as the first and second silicon oxide layers.

14. The method of claim 12, wherein a total thickness of the silicon oxide layers is about 500 Å

to about 10,000 Å

.

15. The method of claim 1, wherein the oxygen precursor comprises atomic oxygen that is generated outside the deposition chamber.

16. The method of claim 15, wherein the atomic oxygen is formed by:

forming a plasma from a gas mixture comprising argon; and

introducing an oxygen precursor to the plasma, wherein the oxygen precursor dissociates to form the atomic oxygen.

17. The method of claim 16, wherein the oxygen precursor is selected from the group consisting of molecular oxygen, ozone, and nitrogen dioxide.

18. The method of claim 15, wherein the atomic oxygen is formed by:

introducing an oxygen precursor into a photodissociation chamber; and

exposing the oxygen precursor to ultraviolet light, wherein the ultraviolet light dissociates the oxygen precursor to form atomic oxygen.

19. The method of claim 15, wherein the organo-silicon precursor and the atomic oxygen are not mixed until after being introduced into the deposition chamber.

20. A method of forming a multilayer silicon oxide film on a substrate, the method comprising:

forming a plurality of silicon oxide layers on the substrate, wherein each silicon oxide layer has a thickness of about 100 Å

to about 200 Å

, and wherein each layer is formed by;

(i) introducing an organo-silicon precursor and an atomic oxygen precursor to a reaction chamber,

(ii) reacting the precursors to form the layer on the substrate, and

(iii) etching the layer to reduce impurities in the layer, wherein the etching of the layer comprises;

exposing the layer to a first plasma having a first density, wherein the first plasma dissociates larger carbon molecules in the layer, and

exposing the layer to a second plasma having a second density that is higher than the first density, wherein the second plasma dissociates silicon-hydroxide bonds in the layer; and

annealing the plurality of layers.

21. The method of claim 20, wherein the atomic oxygen precursor is generated outside the deposition chamber, and wherein the organo-silicon and atomic oxygen precursors are not mixed until after being introduced into the reaction chamber.

22. The method of claim 20, wherein the annealing of the plurality of layers comprises a thermal anneal, a steam anneal, a plasma anneal, an ultraviolet light anneal, an e-beam anneal, or a microwave anneal.

23. The method of claim 20, wherein each of the plurality of layers is formed at a rate of about 125 Å

/min to about 2 μ

m/min.

24. The method of claim 20, wherein each of the layers is etched in about 3 minutes or less.

25. The method of claim 20, wherein the plurality of layers is annealed in about 30 minutes or less.

26. The method of claim 20, wherein the plurality of layers have a wet etch rate ratio (WERR) of about 1.8:

1 to about 1.4;

1.

27. The method of claim 20, wherein the plurality of layers have a—

value of about 4.0 or less.

28. The method of claim 20, wherein the multilayer silicon oxide film has a thickness of about 1000 Å

to about 3000 Å

.

29. The method of claim 20, wherein the annealing of the plurality of layers comprises:

heating the substrate at a first anneal temperature in the presence of steam; and

heating the substrate at a second anneal temperature in dry nitrogen.

30. The method of claim 29, wherein the first anneal temperature is about 650°

C. and the second anneal temperature is about 900°

C.