ALD method to improve surface coverage

• US 6,355,561 B1
• Filed: 11/21/2000
• Issued: 03/12/2002
• Est. Priority Date: 11/21/2000
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Sandhu, Gurtej, Derderian, Garo J.
• Primary Examiner(s): LEBENTRITT, MICHAEL
• Application Number:
  US09/716,288
• Time in Patent Office: 476 Days
• Field of Search: 438/676, 438/687, 438/680, 438/685, 438/798, 438/681, 438/643, 427/582, 427/584, 427/250, 427/255.2, 117/104, 117/99, 117/102, 117/103, 117/952
• US Class Current: 438/676
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• 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 21/28167 on single crystalline silicon, e.g. using a liquid, i.e. chemical oxidation
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76868 Forming or treating discontinuous thin films, e.g. repair, enhancement or reinforcement of discontinuous thin films
• CPC Class Codes: H01L 29/51 Insulating materials associated therewith for MIS structures on thin film semiconductor H01L29/4908

Abstract

A method of depositing a thin film on a substrate in a semiconductor device using Atomic Layer Deposition (ALD) process parameters exposes the substrate to at least one adherent material in a quantity sufficient for the material to adsorb onto the substrate and thereby form an initiation layer. The initiation layer presents at least one first reactive moiety which is then chemically reacted with at least one first reaction material using atomic layer deposition conditions to form a second reactive moiety. The second reactive moiety is then chemically reacted with at least one second reaction material under process conditions sufficient to form a reaction layer over the initiation layer. The process may be repeated to form successive reaction layers over the initiation layer. The adherent material constituting the initiation layer is preferably one which is not substantially degraded by the atomic layer deposition parameters. The initiation layer together with one or more reaction layer(s) constitutes the final film.

Claims

1. A method of depositing a film on a substrate of a semiconductor device, comprising:

a) exposing said substrate to at least one adherent material in a quantity sufficient for said material to adsorb onto said substrate to thereby form an initiation layer, said initiation layer presenting at least one first reactive moiety;

b) chemically reacting said first reactive moiety with at least one first reaction material to form a second reactive moiety; and

c) chemically reacting said second reactive moiety with at least one second reaction material, wherein said steps a) through c) are performed under atomic layer deposition conditions sufficient to form at least one reaction layer over said initiation layer, whereby said initiation layer material is not substantially degraded during said steps b) and c).

2. The method of claim 1, further comprising the step of again reacting said first reaction material with said second reaction material after completion of step c) to form at least one additional reaction layer over said at least one reaction layer.

3. The method of claim 2, wherein said step of again reacting is performed at least five times.

4. The method of claim 3, wherein said step of again reacting is performed at least ten times.

5. The method of claim 1, wherein a level of adsorption by said adherent material is equal to or greater than about 30% after formation of said initiation layer.

6. The method of claim 5, wherein a level of adsorption by said adherent material is greater than about 50%.

7. The method of claim 6, wherein said level is at least about 80%.

8. The method of claim 7, wherein said level is at least about 90%.

9. The method of claim 1, wherein said moiety is sterically favored to react with said at least one first reaction material.

10. The method of claim 1, wherein said adherent material is substantially substrate independent.

11. The method of claim 10, wherein said substrate is comprised of silicon or a silicon-containing compound or alloy.

12. The method of claim 10, wherein said substrate comprises silicon.

13. The method of claim 1, wherein said moiety is a sterically favored ligand group.

14. The method of claim 1, wherein said atomic layer deposition is performed at a temperature within the range of about 100 to about 600°

C.

15. The method of claim 14, wherein said atomic layer deposition is performed at a temperature within the range of about 200 to about 400°

C.

16. The method of claim 15, wherein said atomic layer deposition is performed at a temperature within the range of about 250 to about 350°

C.

17. The method of claim 14, wherein said atomic layer deposition is performed at an operating pressure within the range of about 1.0 milliTorr to about 10 Torr.

18. The method of claim 17, wherein said atomic layer deposition is performed at an operating pressure within the range of about 30 milliTorr to about 1 Torr.

19. The method of claim 1, wherein said adherent material is at least one member selected from the group consisting of titanium-containing compounds.

20. The method of claim 19, wherein said at least one first reaction material is at least one gaseous nitrogen-containing compound, and said adherent material is at least one member from the group of tetrakisdimethylamino titanium and titanium chloride.

21. The method of claim 20, wherein said at least one first reaction material is at least one member selected from the group consisting of nitric oxide, nitrous oxide, nitrogen and ammonia.

22. The method of claim 21, wherein said at least one first reaction material is selected from the group consisting of nitrogen and ammonia.

23. The method of claim 22, wherein said at least one first reaction material is ammonia.

24. The method of claim 20, wherein said at least one second reaction material is at least one member selected from the group consisting of metal bearing compounds.

25. The method of claim 24, wherein said at least one second reaction material is at least one member selected from the group consisting of tungsten-containing compounds.

26. The method of claim 25, wherein said at least one second reaction material is tungsten fluoride (WF₆) and said reaction layer is comprised of WNx.

27. The method of claim 1, wherein steps a), b) and c) are repeated at least twice on different parts of said substrate.

28. The method of claim 2, further comprising the step of repeating steps a), b) and c) on different parts of said substrate.

29. A method of depositing a film on a substrate in a semiconductor device, comprising:

a) exposing said substrate to tetrakisdimethylamino titanium in a quantity sufficient for said compound to adsorb onto said substrate in a manner such that said adsorbed material forms an initiation layer over said substrate and further presents at least one reactive dimethylamino ligand;

b) reacting said at least one dimethylamino ligand with at least one first reaction material selected from the group consisting of nitrogen-bearing compounds to thereby form a second reactive moiety; and

c) reacting said second reactive moiety with a tungsten-bearing compound, wherein said steps a) through c) are performed using an atomic layer deposition process at a temperature of about 250°

C. to about 350°

C. so as to form a reaction layer of tungsten nitride (WNx) over said initiation layer, whereby said initiation layer is not substantially degraded by said atomic layer deposition process.

30. The method of claim 29, wherein said nitrogen-bearing compound is at least one member selected from the group consisting of nitrogen and ammonia gases.

31. The method of claim 29, wherein said tungsten-bearing compound is tungsten hexafluoride.

32. The method of claim 29, wherein said initiation layer is at least about 95% intact after said atomic layer deposition process.

33. A method of depositing a film on a substrate of a semiconductor device, comprising:

a) exposing said substrate to at least one chemisorbent material in a quantity sufficient for said material to stick onto said substrate to thereby form an initiation layer, said initiation layer presenting at least one first reactive moiety;

b) chemically reacting said first reactive moiety with at least one first reaction material to form a second reactive moiety; and

c) chemically reacting said second reactive moiety with at least one second reaction material, wherein said steps a) through c) are performed under atomic layer deposition conditions sufficient to form at least one reaction layer over said initiation layer, whereby said initiation layer material is not substantially degraded during said steps b) and c).