Silicon Dioxide Thin Films by ALD

• US 20090209081A1
• Filed: 12/19/2008
• Published: 08/20/2009
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM International NV
• Inventors: MATERO, Raija H., Haukka, Suvi P.
• Granted Patent: US 8,501,637 B2
• Time in Patent Office: Days
• US Class Current: 438/400
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/402 Silicon dioxide
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02219 the compound comprising silicon and nitrogen
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/31608 Deposition of SiO2 H01L21/31625, H01L21/31629 and H01L21/31633 take precedence

Abstract

Methods are provided for depositing silicon dioxide containing thin films on a substrate by atomic layer deposition ALD. By using disilane compounds as the silicon source, good deposition rates and uniformity are obtained.

Claims

1. An atomic layer deposition (ALD) process for producing a thin film comprising silicon dioxide on a substrate comprising a deposition cycle comprising:

contacting a substrate with a vaporized silicon compound such that the silicon compound adsorbs to the substrate; and

converting the adsorbed silicon compound into silicon dioxide by contacting it with a reactive vaporized oxygen source compound;

wherein the silicon compound has a Si—

Si bond and formula of;

R^III_3-x(R^IIR^IN)_x—

Si—

Si—

(N—

R^IR^II)_yR^III_3-y,

wherein the x is selected from 1 to 3;

y is selected from 1 to 3;

R^I is selected from the group consisting of hydrogen, alkyl and substituted alkyl;

R^II is selected from the group consisting of alkyl and substituted alkyl; and

R^III is selected from the group consisting of hydrogen, hydroxide (—

OH), amino (—

NH₂), alkoxy, alkyl and substituted alkyl;

and wherein each x, y, R^III, R^II and R^I can be selected independently from each other.

2. The process of claim 1, wherein the silicon compound is hexakis(monoalkylamino)disilane (R^II—

NH)₃—

Si—

Si—

(NH—

R^II)₃.

3. The process of claim 1, wherein the silicon compound is hexakis(ethylamino)disilane (Et-NH)₃—

Si—

Si—

(NH-Et)₃.

4. The process of claim 1, wherein the deposition cycle is repeated until a silicon dioxide thin film of the desired thickness is formed.

5. The process of claim 1, wherein the temperature of the silicon compound is held above 60°

C. during deposition.

6. The process of claim 5, wherein the deposition temperature is from about 150°

C. to 350°

C.

7. The process of claim 5, wherein the deposition temperature is from about 250°

C. to 300°

C.

8. The process of claim 1, wherein growth rate of the film is above 0.8 Å

/cycle.

9. The process of claim 1, wherein growth rate of the film is above 1.0 Å

/cycle.

10. The process of claim 1, wherein contacting a substrate with a vaporized silicon compound comprises supplying the silicon compound in a pulse of about 0.1 to about 5 seconds.

11. The process of claim 1, wherein contacting a substrate with a vaporized oxygen source compound comprises supplying an oxygen source compound in a pulse of about 0.1 to about 5 seconds.

12. The process of claim 1, wherein the process is performed in a flow-type reactor.

13. The process of claim 1, wherein the process is performed in a batch ALD reactor capable of processing more than one substrate.

14. The process of claim 13, wherein the process conditions are selected such that the thickness variation from substrate to substrate processed in the batch ALD reactor is less than about 0.5%.

15. The process of claim 13, wherein the thickness variation within each wafer processed in the batch ALD reactor is less than about 0.5%.

16. The process of claim 13, wherein the batch ALD reactor is capable of processing more than 100 wafers in one batch.

17. The process of claim 1, wherein the oxygen source compound comprises ozone.

18. The process of claim 17, wherein the ozone comprises a mixture of ozone/oxygen, ozone having concentration from about 5 vol-% to about 40 vol-%.

19. The process of claim 1, wherein the oxygen source compound comprises atomic oxygen.

20. The process of claim 1, wherein the oxygen source compound is selected from the group consisting of oxygen plasma and oxygen radicals.

21. The process of claim 1, wherein the deposited film has less than 2 at-% of nitrogen as an impurity.

22. The process of claim 1, wherein the deposited film has less than 1 at-% of carbon as an impurity.

23. The process of claim 1, wherein the process is used for filling trenches.

24. The process of claim 1, wherein the step coverage of the process is more than 90%.

25. The process of claim 1, wherein the process is used for depositing spacers.

26. A method for forming a silicon dioxide thin film on a substrate in a reaction chamber by atomic layer deposition, the method comprising a deposition cycle comprising:

providing a vapor phase pulse of a first reactant comprising a first silicon source precursor to the reaction chamber such that it forms no more than a monolayer on the substrate;

removing excess first reactant from the reaction chamber;

providing a vapor phase pulse of a second reactant comprising an oxygen source to the reaction chamber; and

removing excess second reactant and any reaction byproducts from the reaction chamber;

wherein the providing and removing steps are repeated until a thin silicon dioxide film of a desired thickness is obtained, and wherein the silicon compound is hexakis(monoalkylamino)disilane (R^II—

NH)₃—

Si—

Si—

(NH—

R^II)₃ and R^II is selected from the group consisting of alkyl and substituted alkyl.

27. The method of claim 26, wherein the deposition temperature is from about 150°

C. to 350°

C.

28. A method for forming a silicon dioxide thin film by atomic layer deposition on a substrate in a reaction chamber comprising:

alternately and sequentially providing a vapor phase reactant pulse comprising a silicon precursor and a vapor phase reactant pulse comprising an oxygen precursor to the reaction chamber;

wherein the vapor phase reactant pulses are repeated until a thin film of a desired thickness is obtained;

wherein the silicon compound is hexakis(ethylamino)disilane (Et-NH)₃—

Si—

Si—

(NH-Et)₃.

29. The method of claim 28, wherein the deposition temperature is from about 250°

C. to 300°

C.