Insulating layers in semiconductor devices having a multi-layer nanolaminate structure of SiNx thin film and BN thin film and methods for forming the same

• US 6,740,977 B2
• Filed: 04/24/2003
• Issued: 05/25/2004
• Est. Priority Date: 04/24/2002
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hyung, Yong-Woo, Kim, Young-Seok, Kang, Man-Sug, Ahn, Jae-Young
• Primary Examiner(s): Fourson, George
• Assistant Examiner(s): Toledo, Fernando L.
• Application Number:
  US10/422,283
• Publication Number:
  US 20030201540A1
• Time in Patent Office: 397 Days
• Field of Search: 257/760, 438/624, 438/643, 438/778
• US Class Current: 257/760
• CPC Class Codes: C23C 16/342 Boron nitride
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/45529 specially adapted for making a layer stack of alternating different compositions or gradient compositions
• CPC Class Codes: C23C 16/45536 Use of plasma, radiation or electromagnetic fields
• CPC Class Codes: H01L 21/02112 characterised by the material of the layer
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/28185 with a treatment, e.g. annealing, after the formation of the gate insulator and before the formation of the definitive gate conductor
• CPC Class Codes: H01L 21/28202 in a nitrogen-containing ambient, e.g. nitride deposition, growth, oxynitridation, NH3 nitridation, N2O oxidation, thermal nitridation, RTN, plasma nitridation, RPN
• CPC Class Codes: H01L 21/318 composed of nitrides
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: H01L 21/3211 Nitridation of silicon-containing layers
• CPC Class Codes: H01L 21/76828 thermal treatment
• CPC Class Codes: H01L 21/76832 Multiple layers
• CPC Class Codes: H01L 23/3192 Multilayer coating
• CPC Class Codes: H01L 23/53295 Stacked insulating layers
• CPC Class Codes: H01L 29/511 with a compositional variation, e.g. multilayer structures H01L29/516 takes precedence
• CPC Class Codes: H01L 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/19041 : being a capacitor

Abstract

The present invention discloses a novel insulating layer for use in semiconductor devices, the insulating layer having a multi-layer nanolaminate structure consisting of alternating boron nitride thin films and silicon nitride thin films, each of a controlled, desired thickness, together with methods for forming the same.

The insulating layer of the present invention has a multi-layer nanolaminate structure consisting of alternating boron nitride thin films and silicon nitride thin filmsformed by the steps of: (a) depositing a silicon nitride thin film on a wafer, (b) depositing a boron nitride thin film on the silicon nitride thin film, and (c) forming the multi-layer nanolaminate thin film by alternately repeating steps (a) and (b).

Claims

1. A semiconductor device having improved etching properties comprising a wafer having an insulating layer with bottom and top portions along at least a surface thereof, wherein said insulating layer is specially prepared with alternating thin film layers of silicon nitride and boron nitride, each being of a controlled thickness, so as to exhibit the properties of a relatively low dielectric constant and a relatively low etching rate during high temperature, wet chemical etch processing, said insulating layer consisting essentially of at least two silicon nitride thin film layers, each such silicon nitride thin film layer representing about 25-35 silicon nitride ALD deposition cycles, said silicon nitride thin film layers alternating with at least two boron nitride thin film layers, each such boron nitride thin film layer representing about 35-45 boron nitride ALD deposition cycles.

2. A semiconductor device according to claim 1, wherein the thickness of each silicon nitride thin film layer is more than that of a monolayer of silicon nitride, but less than about 200 Å

.

3. A semiconductor device according to claim 1, wherein the thickness of each boron nitride thin film layer is more than that of a monolayer of boron nitride, but less than about 200 Å

.

4. A semiconductor device according to claim 1, wherein the thin film layer adjacent to a surface of said wafer is a silicon nitride thin film.

5. A semiconductor device according to claim 1, wherein the thin film layers which form the bottom and the top portions of said insulating layer are silicon nitride thin films.

6. A semiconductor device according to claim 1, wherein said insulating layer comprises two of said silicon nitride thin film layers alternating with two of said boron nitride thin film layers.

7. A semiconductor device according to claim 1, wherein said insulating layer comprises more than two of said silicon nitride thin film layers alternating with at least two of said boron nitride thin film layers.

8. A semiconductor device according to claim 1, wherein each silicon nitride thin film layer comprises sequential depositions of 30 monolayers of silicon nitride.

9. A semiconductor device according to claim 1, wherein each boron nitride thin film layer comprises sequential depositions of 40 monolayers of boron nitride.

10. A semiconductor device according to claim 1, wherein each silicon nitride thin film layer is of substantially uniform thickness.

11. A semiconductor device according to claim 1, wherein each boron nitride thin film layer is of substantially uniform thickness.

12. A method for forming an insulating layer specially prepared with alternating thin film layers of silicon nitride and boron nitride, each being of a controlled thickness, so as to exhibit the properties of a relatively low dielectric constant and a relatively low etching rate during high temperature, wet chemical etch processing on at least a surface of a semiconductor device, said method comprising the steps of:

(a) forming a silicon nitride thin film representing about 25-35 silicon nitride ALD deposition cycles on a surface of a semiconductor wafer;

(b) forming a boron nitride thin film representing about 35-45 boron nitride ALD deposition cycles on the previously formed silicon nitride thin film; and

,

(c) forming a multi-layer nanolaminate thin film on the surface of the wafer by alternately repeating steps (a) and (b).

13. A method according to claim 12, wherein during the deposition cycles the temperature of the wafer is maintained at about 400°

C. to about 600°

C., and the deposition pressure is maintained at about 1 to 3 torr.

14. A method according to claim 12, wherein the silicon nitride thin films and the boron nitride thin films are sequentially deposited in-situ.

15. A method according to claim 12, wherein a depositing cycle for forming each silicon nitride thin film comprises the sequential steps of:

introducing a first silicon nitride process gas containing silicon Si to a chamber containing the wafer such that at least a portion of said first silicon nitride process gas is adsorbed on a surface of the wafer;

introducing a substantially inert second silicon nitride process gas to the chamber to purge the chamber and to exhaust unadsorbed first silicon nitride process gas;

introducing a third silicon nitride process gas containing a reactive nitrogen entity to the chamber to react with the first silicon nitride process gas adsorbed on the wafer surface; and

,

introducing a substantially inert fourth silicon nitride process gas to the chamber to purge the chamber and to exhaust unreacted third silicon nitride process gas and reaction by-products.

16. A method according to claim 15, wherein the first silicon nitride process gas is selected from the group consisting of SiH₂Cl₂, SiCl₄, Si₂Cl₆, and SiH₄.

17. A method according to claim 15, wherein the second silicon nitride process gas and the fourth silicon nitride process gas are each selected from the group consisting of argon, helium and nitrogen gas.

18. A method according to claim 15, wherein the third silicon nitride process gas is selected from one of either NH₃ or N₂H₄ in the form of a gas or as a radical type, or, alternatively, a mixture of N₂ and H₂ as a mixture of a radical type.

19. A method according to claim 12, wherein a depositing cycle for forming each boron nitride thin film comprises the sequential steps of:

introducing a first boron nitride process gas containing boron B to a chamber containing the wafer such that at least a portion of said first boron nitride process gas is adsorbed on a surface of a previously-deposited silicon nitride thin film;

introducing a substantially inert second boron nitride process gas to the chamber to purge the chamber and to exhaust unadsorbed first boron nitride process gas;

introducing a third boron nitride process gas containing a reactive nitrogen entity to the chamber to react with the first boron nitride process gas adsorbed on the silicon nitride thin film; and

,

introducing a substantially inert fourth boron nitride process gas to the chamber to purge the chamber and to exhaust unreacted third boron nitride process gas and reaction by-products.

20. A method according to claim 19, wherein the first boron nitride process gas is selected from the group consisting of BCl₃, BBr₃, B₂H₆, and BF₃.

21. A method according to claim 19, wherein the second boron nitride process gas and the fourth boron nitride process gas are each selected from the group consisting of argon, helium and nitrogen gas.

22. A method according to claim 19, wherein the third boron nitride process gas is selected from one of either NH₃ or N₂H₄ in the form of a gas or as a radical type, or, alternatively, a mixture of N₂ and H₂ as a mixture of a radical type.

23. A semiconductor device having improved etching properties comprising a wafer having an insulating layer specially prepared to exhibit the properties of a relatively low dielectric constant below about 5 and a relatively low etching rate below about 10 Å

/min, during high temperature, wet chemical etch processing formed along at least a surface thereof, said insulating layer being formed by the process of;

(a) forming a silicon nitride thin film representing about 25-35 silicon nitride ALD deposition cycles on a surface of a semiconductor wafer;

(b) forming a boron nitride thin film representing about 35-45 boron nitride ALD deposition cycles on the previously formed silicon nitride thin film; and

,

(c) forming a multi-layer nanolaminate thin film on the surface of the wafer by alternately repeating steps (a) and (b).

24. A semiconductor device according to claim 23 wherein during the deposition cycles the temperature of the wafer is maintained at about 400°

C. to about 600°

C., and the deposition pressure is maintained at about 1 to 3 torr.

25. A semiconductor device according to claim 23 wherein the silicon nitride thin films and the boron nitride thin films are sequentially deposited in-situ.

26. A semiconductor device according to claim 23 wherein a depositing cycle for forming each silicon nitride thin film comprises the sequential steps of:

introducing a first silicon nitride process gas containing silicon Si to a chamber containing the wafer such that at least a portion of said first silicon nitride process gas is adsorbed on a surface of the wafer;

introducing a substantially inert second silicon nitride process gas to the chamber to purge the chamber and to exhaust unadsorbed first silicon nitride process gas;

introducing a third silicon nitride process gas containing a reactive nitrogen entity to the chamber to react with the first silicon nitride process gas adsorbed on the wafer surface; and

,

introducing a substantially inert fourth silicon nitride process gas to the chamber to purge the chamber and to exhaust unreacted third silicon nitride process gas and reaction by-products;

and, wherein a depositing cycle for forming each boron nitride thin film comprises the sequential steps of;

introducing a first boron nitride process gas containing boron B to a chamber containing the wafer such that at least a portion of said first boron nitride process gas is adsorbed on a surface of a previously-deposited silicon nitride thin film;

introducing a substantially inert second boron nitride process gas to the chamber to purge the chamber and to exhaust unadsorbed first boron nitride process gas;

introducing a third boron nitride process gas containing a reactive nitrogen entity to the chamber to react with the first boron nitride process gas adsorbed on the silicon nitride thin film; and

,

introducing a substantially inert fourth boron nitride process gas to the chamber to purge the chamber and to exhaust unreacted third boron nitride process gas and reaction by-products.

27. A semiconductor device according to claim 23 wherein each silicon nitride thin film layer is of substantially uniform thickness and wherein each boron nitride thin film layer is of substantially uniform thickness.

28. A semiconductor device according to claim 23 wherein the number of depositing cycles used for forming each silicon nitride thin film is 30 times, and the number of depositing cycles used for forming each boron nitride thin film is 40 times.

29. A semiconductor device according to claim 26, wherein the first silicon nitride process gas is selected from the group consisting of SiH₂Cl₂, SiCl₄, Si₂Cl₆, and SiH₄.

30. A semiconductor device according to claim 26, wherein the second silicon nitride process gas and the fourth silicon nitride process gas are each selected from the group consisiting of argon, helium and nitrogen gas.

31. A semiconductor device according to claim 26, wherein the third silicon nitride process gas is selected from one of either NH₃ or N₂H₄ in the form of a gas or as a radical type, or, alternatively, a mixture of N₂ and H₂ as a mixture of a radical type.

32. A semiconductor device according to claim 26, wherein the first boron nitride process gas is selected from the group consisting of BCl₃, BBr₃, B₂H₆, and BF₃.

33. A semiconductor device according to claim 26, wherein the second boron nitride process gas and the fourth boron nitride process gas are each selected from the group consisting of argon, helium and nitrogen gas.

34. A semiconductor device according to claim 26, wherein the third boron nitride process gas is selected from one of either NH₃ or N₂H₄ in the form of a gas or as a radical type, or, alternatively, a mixture of N₂ and H₂ as a mixture of a radical type.