Methods of forming an ALD-inhibiting layer using a self-assembled monolayer

• US 20170114451A1
• Filed: 10/17/2016
• Published: 04/27/2017
• Est. Priority Date: 10/21/2015
• Status: Active Grant

• Current Assignee: Veeco Instruments Incorporated
• Original Assignee: Ultratech Incorporated (Veeco Instruments Incorporated)
• Inventors: Lecordier, Laurent
• Granted Patent: US 10,316,406 B2
• Time in Patent Office: Days
• CPC Class Codes: C22B 15/00 Obtaining copper
• CPC Class Codes: C22B 5/12 by gases
• CPC Class Codes: C23C 16/0272 Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• CPC Class Codes: C23C 16/04 Coating on selected surface areas, e.g. using masks
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C23C 16/45527 characterized by the ALD cycle, e.g. different flows or temperatures during half-reactions, unusual pulsing sequence, use of precursor mixtures or auxiliary reactants or activations
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/321 After 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

Methods of forming an ALD-inhibiting layer using a layer of SAM molecules include providing a metalized substrate having a metal M and an oxide layer of the metal M. A reduction gas that includes a metal Q is used to reduce the oxide layer of the metal M, leaving a layer of form of M+MQ_yO_x atop the metal M. The SAM molecules are provided as a vapor and form an ALD-inhibiting SAM layer on the M+MQ_yO_x layer. Methods of performing S-ALD using the ALD-inhibiting SAM layer are also disclosed.

Claims

1. A method of forming an ALD-inhibiting layer on a metal M covered with an oxide layer of the metal M (“

metal-oxide layer”

), comprising;

a) reducing the metal-oxide layer by exposing the metal-oxide layer to a reduction gas that includes a metal Q to form a M+MQ_xO_y layer on the metal M; and

b) exposing the M+MQ_xO_y layer to self-assembled-monolayer “

SAM”

) molecules in a vapor phase, wherein the SAM molecules form on the M+MQ_xO_y layer a SAM layer that is ALD inhibiting.

2. The method according to claim 1, wherein:

the metal M is Cu, Ni, Fe or Co; and

the metal Q is Al, Hf, Zr, Si, Ti or Zn.

3. The method according to claim 1, wherein the SAM molecules are thiol molecules.

4. The method according to claim 1, wherein:

the metal M is copper;

the metal-oxide layer is made from copper oxide;

the reduction gas comprises trimethylaluminum (TMA);

the SAM molecules are thiol molecules; and

the M+MQ_xO_y layer is Cu+CuAlO₂layer.

5. The method according to claim 1, wherein act a) is carried out at a temperature of between 120°

C. and 250°

C.

6. The method according to claim 1, wherein acts a) and b) are carried out in a vacuum condition less than 1 Torr.

7. The method according to claim 1, wherein the metal-oxide layer has a thickness in the range from 1 nm to 5 nm.

8. The method according to claim 1, wherein the ALD-inhibiting layer substantially inhibits the formation of an ALD film thereon for at least 100 ALD cycles.

9. The method according to claim 8, wherein the ALD-inhibiting layer substantially inhibits the formation of an ALD film thereon for at least 150 ALD cycles.

10. The method according to claim 1, further comprising forming the metal M as a patterned metal layer on a semiconductor substrate.

11. The method according to claim 1, wherein the metal M is formed as a pattern on a dielectric layer of a semiconductor substrate, and further comprising performing selective-area ALD by:

performing an ALD process on the dielectric layer and the SAM layer that covers the metal M, thereby forming an ALD film on the dielectric layer but not the SAM layer.

12. The method according to claim 11, wherein the dielectric layer is an oxide layer.

13. The method according to claim 11, further comprising removing the SAM layer.

14. The method according to claim 1, wherein act a) is performed in less than 720 seconds.

15. A method of performing selective-area atomic layer deposition (“

S-ALD”

), comprising;

a) defining a layer of metal M (“

metal layer”

) on a dielectric layer supported by a semiconductor substrate, wherein the metal layer defines a pattern, and wherein the metal layer is covered by a layer of oxide of the metal M (“

metal-oxide layer”

);

b) reducing the metal-oxide layer by exposing the metal-oxide layer to a reduction gas that includes a metal Q to form a M+MQ_xO_y layer on the metal layer;

c) exposing the M+MQ_xO_y layer and the dielectric layer to self-assembled-monolayer (SAM) molecules in a vapor phase, wherein the SAM molecules form on the M+MQ_xO_y layer a SAM layer to define an ALD-inhibiting layer, and wherein no SAM layer is formed on the dielectric layer; and

d) performing an ALD process to deposit an ALD film, wherein the ALD film forms on the dielectric layer but not on the SAM layer.

16. The method according to claim 15, wherein:

the metal M is Cu, Ni, Fe or Co; and

the metal Q is Al, Hf, Zr, Si, Ti or Zn.

17. The method according to claim 15, further comprising an act e) of removing the SAM layer.

18. The method according to claim 15, wherein act b) is performed within 720 seconds.

19. The method according to claim 15, wherein the SAM molecules consist of thiol molecules.

20. The method according to claim 15, wherein the dielectric layer comprises an SiO₂ layer.

21. The method according to claim 15, wherein:

the metal M is copper;

the metal-oxide layer is made from copper oxide;

the reduction gas comprises trimethylaluminum (TMA);

the SAM molecules are thiol molecules; and

the M+MQ_xO_y layer is Cu+CuAlO₂ Layer.

22. The method according to claim 15, wherein the SAM layer substantially inhibits the formation of an ALD film thereon for at least 100 ALD cycles.

23. The method according to claim 22, wherein the SAM layer substantially inhibits the formation of an ALD film thereon for at least 150 ALD cycles.

24. The method according to claim 15, wherein act b) is carried out at a temperature of between 120°

C. and 250°

C.

25. The method according to claim 15, wherein acts b) and c) are carried out in a vacuum condition less than 1 Torr.

26. The method according to claim 15, wherein the metal-oxide layer has a thickness in the range from 1 nm to 5 nm.

27. The method according to claim 15, wherein the reduction gas comprises trimethylaluminum (TMA) or alkyl amide.

28. The method according to claim 15, wherein acts b), c) and d) are carried out in a single ALD chamber.