PLASMA-ENHANCED DEPOSITION PROCESS FOR FORMING A METAL OXIDE THIN FILM AND RELATED STRUCTURES

• US 20090269941A1
• Filed: 04/25/2008
• Published: 10/29/2009
• Est. Priority Date: 04/25/2008
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM America Incorporated (ASM International NV)
• Inventors: Marcus, Steven, Raisanen, Petri
• Granted Patent: US 8,383,525 B2
• Time in Patent Office: Days
• US Class Current: 438/778
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/45536 Use of plasma, radiation or electromagnetic fields
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• 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 21/31641 Deposition of Zirconium oxides, e.g. ZrO2

Abstract

Methods of forming metal oxide thin films and related structures are provided. One embodiment of the methods includes conducting a plurality of cycles of deposition on a substrate. Each cycle includes supplying oxygen gas and an inert gas into a reaction space substantially continuously during the cycle. A metal precursor is supplied into the reaction space for a first duration. The metal precursor is a cyclopentadienyl compound of the metal. After the metal precursor is supplied, the continuously flowing oxygen gas is activated for a second duration to generate a plasma in the reaction space. The cycle is conducted at a temperature below about 400° C. The methods can be performed after forming a structure on the substrate, wherein the structure is formed of a material which is physically and/or chemically unstable at a high temperature.

Claims

1. A method of forming a metal oxide thin film over a substrate, the method comprising:

conducting a deposition cycle comprising;

supplying oxygen gas and an inert gas into a reaction space substantially continuously during the cycle, wherein a substrate is disposed in the reaction space;

supplying a metal precursor into the reaction space, the metal precursor comprising a cyclopentadienyl compound of the metal; and

activating the oxygen gas to expose the substrate to plasma-excited oxygen species in the reaction space.

2. The method of claim 1, wherein activating the oxygen gas comprises generating an in-situ plasma in the reaction space.

3. The method of claim 1, wherein the cycle is conducted at a temperature below about 400°

C.

4. The method of claim 3, wherein the cycle is conducted at a temperature between about 100°

C. and about 250°

C.

5. The method of claim 1, wherein the substrate includes a structure pre-formed thereon, and wherein the structure is formed of a material that is unstable at a temperature greater than about 250°

C.

6. The method of claim 5, wherein the material is unstable at a temperature greater than about 100°

C.

7. The method of claim 6, wherein the material comprises at least one of low-k dielectric materials, organic semiconductor materials, and organic light emitting materials.

8. The method of claim 1, wherein the metal is selected from the group consisting of Zr, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, Lu, Sr, Ba, Hf, Ta, Y, Ti, and Nb.

9. The method of claim 8, wherein the cyclopentadienyl compound is selected from the group consisting of mono-cyclopentadienyl compounds and bis-cyclopentadienyl compounds.

10. The method of claim 9, wherein the bis-cyclopentadienyl compound is represented by Formula 1:

(R¹Cp)₂MR²R³ 

 

Formula 1

wherein Cp is a cyclopentadienyl ligand;

wherein M is a metal selected from the group consisting of Zr, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, Lu, Sr, Ba, Hf, Ta, Y, Ti, and Nb;

wherein R¹ is hydrogen, a C5-C6 alkyl group, a C5-C6 alkoxy group, or an amido group; and

wherein R² and R³ are the same as or different from each other, and each of R² and R³ is a C5-C6 alkyl group, a C5-C6 alkoxy group, or an amido group.

11. The method of claim 9, wherein the mono-cyclopentadienyl compound is represented by Formula 2:

(R¹Cp)MR²R³R⁴ 

 

Formula 2

wherein Cp is a cyclopentadienyl ligand;

wherein M is a metal selected from Zr, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, Lu, Sr, Ba, Hf, Ta, Y, Ti, and Nb;

wherein R¹ is hydrogen, a C5-C6 alkyl group, a C5-C6 alkoxy group, or an amido group; and

wherein R², R³, and R⁴ are the same as or different from one another and each of R², R³, and R⁴ is a C5-C6 alkyl group, a C5-C6 alkoxy group, or an amido group.

12. The method of claim 1, wherein the cycle is conducted for a duration of about 400 milliseconds to about 8,000 milliseconds.

13. The method of claim 12, wherein supplying the metal precursor comprises supplying the metal precursor for a period of time between about 200 milliseconds and about 2,000 milliseconds.

14. The method of claim 12, wherein activating the oxygen gas comprises applying RF power to the reaction space for a period of time between about 200 milliseconds and about 2,000 milliseconds.

15. The method of claim 1, wherein the cycle further comprises purging excess metal precursor from the reaction space after supplying the metal precursor and before activating the oxygen gas.

16. The method of claim 15, wherein purging the excess metal precursor comprises flowing the oxygen gas and the inert gas.

17. The method of claim 1, wherein the cycle does not include purging excess metal precursor from the reaction space after supplying the metal precursor and before activating the oxygen gas.

18. The method of claim 1, wherein the cycle further comprises purging excess activated oxygen gas after activating the oxygen gas.

19. The method of claim 18, wherein purging the excess activated oxygen gas comprises flowing the oxygen gas and the inert gas.

20. The method of claim 1, wherein the inert gas comprises argon (Ar) gas.

21. The method of claim 1, further comprising repeating the cycle until a metal oxide film of a selected thickness is formed.

30. An integrated circuit device comprising:

a substrate; and

a metal oxide film formed over the substrate, the metal oxide film being made by the method of claim 1.

31. The device of claim 30, further comprising a structure formed of a material that is unstable at a temperature greater than about 250°

C.

32. The device of claim 31, wherein the material is unstable at a temperature greater than about 100°

C.

33. The device of claim 32, wherein the material comprises at least one selected from the group consisting of a low-k dielectric material, an organic semiconductor material, and an organic light emitting material.

22. A method of making an integrated circuit device, the method comprising:

loading a substrate into a reaction space; and

conducting a plurality of deposition cycles at a temperature of about 200°

C. or less to form a layer, each cycle comprising;

supplying oxygen gas substantially continuously into the reaction space during the cycle; and

supplying a metal precursor into the reaction space for a first duration, the first duration lasting less than an entirety of the cycle, the metal precursor comprising a cyclopentadienyl compound of the metal,

wherein the layer is deposited at a growth rate of about 0.40 Å

/cycle or greater, and

wherein the deposited layer has a thickness uniformity of about 1.0 σ

or less.

23. The method of claim 22, wherein conducting the deposition cycles comprises conducting plasma-enhanced atomic layer deposition (PEALD) cycles.

24. The method of claim 22, wherein each cycle further comprises applying radio frequency (RF) power to the reaction space for a second duration to generate oxygen plasma after supplying the metal precursor.

25. The method of claim 22, wherein the cycle further comprises supplying an inert gas substantially continuously into the reaction space during the cycle.

26. The method of claim 25, wherein the second duration starts about 0 milliseconds to about 50 milliseconds after the end of the first duration.

27. The method of claim 25, wherein the plurality of cycles comprises a first cycle and a second cycle immediately following the first cycle, and wherein the first duration of the second cycle starts about 0 milliseconds to about 50 milliseconds after the end of the second duration of the first cycle.

28. The method of claim 22, further comprising forming a structure over the substrate prior to conducting the cycles, wherein the structure is formed of a material that is unstable at a temperature greater than about 200°

C.

29. The method of claim 22, the deposited layer has a k value of about 35 or higher.