Methods of fabricating a selectively deposited tungsten nitride layer and metal wiring using a tungsten nitride layer

• US 6,087,257 A
• Filed: 11/15/1996
• Issued: 07/11/2000
• Est. Priority Date: 11/12/1996
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ko, Dae-hong, Park, Byung-lyul, Lee, Sang-in, Ha, Jung-min
• Primary Examiner(s): Fahmy, Wael
• Assistant Examiner(s): EATON, KURT M
• Application Number:
  US08/751,153
• Time in Patent Office: 1,334 Days
• Field of Search: 438/756, 438/203, 438/190, 438/629, 438/641, 438/674, 438/675, 438/680, 438/685, 438/909, 438/935
• US Class Current: 438/675
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76855 After-treatment introducing at least one additional element into the layer
• CPC Class Codes: H01L 21/76879 by selective deposition of conductive material in the vias, e.g. selective C.V.D. on semiconductor material, plating plating on semiconductors in general H01L21/288

Abstract

Methods for fabricating a tungsten nitride layer in a semiconductor substrate having an insulating layer formed thereon. The methods include forming a contact hole through the insulating layer. A tungsten nitride layer is then selectively deposited only in the contact hole by selectively reacting a nitrogen-containing gas with a tungsten source gas so as to prevent formation of tungsten nitride layer on the insulating layer outside the contact hole. Methods or fabricating metal wiring utilizing the methods of fabricating a tungsten nitride layer are also provided.

Claims

1. A method for fabricating a tungsten nitride layer in a semiconductor substrate having an insulating layer formed thereon, comprising the steps of:

forming a contact hole through the insulating layer;

forming an ohmic layer by forming a titanium silicide layer in the contact hole; and

then

selectively depositing a tungsten nitride layer only in the contact hole and sidewalls of the contact hole by selectively reacting a nitrogen-containing gas and a tungsten source gas by controlling flow rates of the nitrogen-containing gas and the tungsten source gas such that the flow rate of the nitrogen containing gas is from about 2 to about 7 times the flow rate of the tungsten source gas, so as to prevent formation of tungsten nitride layer on the insulating layer outside the contact hole.

2. A method of fabricating a tungsten nitride layer according to claim 1, wherein said step of selectively depositing a tungsten nitride layer comprises selectively reacting a gas mixture of a nitrogen-containing gas and a tungsten source gas with a reducing agent gas thereby facilitating the reaction of the nitrogen-containing gas with the tungsten source gas.

3. A method of fabricating a tungsten nitride layer according to claim 2, wherein said step of selectively reacting comprises the steps of:

placing the semiconductor substrate in a process chamber;

injecting nitrogen containing gas into the process chamber at a controlled flow rate;

injecting a tungsten source gas into the process chamber at a controlled flow rate;

injecting a reducing agent gas into the process chamber at a controlled flow rate; and

wherein the flow rate of the nitrogen containing gas, the flow rate of the tungsten source gas and the flow rate of the reducing agent gas are controlled so as to prevent formation of tungsten nitride on the insulating layer outside the contact hole.

4. A method for fabricating a tungsten nitride layer according to claim 1, wherein a conductive layer is formed of a material selected from the group consisting of aluminum (Al), tungsten (W), molybdenum (Mo), cobalt (Co), titanium (Ti), copper (Cu), platinum (Pt), a silicide compounds of aluminum, tungsten, molybdenum, cobalt, titanium, copper and platinum, and alloys of aluminum, tungsten, molybdenum, cobalt, titanium, copper and platinum and exposed by the contact hole.

5. A method for fabricating a tungsten nitride layer according to claim 1, wherein the insulating layer is formed of a material selected from the group consisting of silicon oxide, silicon nitride, doped silicon oxide and doped silicon nitride.

6. A method for fabricating a tungsten nitride layer according to claim 1, wherein the tungsten source gas is selected from the group consisting of WF₆ and WC16.

7. A method for fabricating a tungsten nitride layer according to claim 1, wherein the nitrogen-containing gas is selected from the group consisting of N₂, NH₃, and methyl hydrazine.

8. A method for fabricating a tungsten nitride layer according to claim 2, wherein said reducing agent gas is selected from the group consisting of H₂, SiH₄, SiH₂ Cl₂, and PH₃.

9. A method for fabricating a tungsten nitride layer according to claim 3, wherein the flow rate of the nitrogen-containing gas is from about 0.5 to about 100 times the flow rate of the tungsten source gas.

10. A method for fabricating a tungsten nitride layer according to claim 3, wherein the flow rate of the reducing agent gas is from about 0 to about 500 times the flow rate of the tungsten source gas.

11. A method for fabricating a tungsten nitride layer according to claim 10, wherein the flow-rate of the reducing agent gas is from about 20 to about 50 times the flow rate of the tungsten source gas.

12. A method for fabricating a tungsten nitride layer according to claim 1, wherein the contact hole is formed so as to extend into a conductive region exposed by the contact hole so as to provide a portion of a side-wall of the contact hole formed of a conductive material.

13. A method for fabricating metal wiring for a semiconductor device, comprising the steps of:

(a) forming a contact hole through an insulating layer to expose a conductive region;

(b) forming an ohmic layer of tungsten silicide on the conductive region exposed by the contact hole;

(c) forming, in a process chamber, a tungsten nitride layer on the ohmic layer and sidewalls of the contact hole by selectively reacting a nitrogen-containing gas and a tungsten source gas at a temperature in a range of from about 200 to about 700°

C. by controlling flow rates of the nitrogen-containing gas and the tungsten source gas so that the flow rate of the nitrogen-containing gas is from about 2 to about 7 times the flow rate of the tungsten source gas, so as to control the location for formation of the tungsten nitride layer to prevent formation of a tungsten nitride layer on the insulating layer outside the contact hole; and

(d) forming a metal layer on the tungsten nitride layer in situ in the same process chamber.

14. A method of fabricating metal wiring according to claim 13, wherein said step of forming a tungsten nitride layer comprises depositing a tungsten nitride layer on the ohmic layer in-situ by selectively reacting a gas mixture of a nitrogen-containing gas and a tungsten source gas with a reducing agent gas.

15. A method of fabricating metal wiring according to claim 14, wherein said step of forming a tungsten nitride layer comprises the following steps:

placing the semiconductor device in a process chamber;

injecting nitrogen containing gas into the process chamber at a controlled flow rate;

injecting a tungsten source gas into the process chamber at a controlled flow rate;

injecting a reducing agent gas into the process chamber at a controlled flow rate; and

wherein the flow rate of the nitrogen containing gas, the flow rate of the tungsten source gas and the flow rate of the reducing agent gas are controlled so as to control the location for formation of the tungsten nitride layer.

16. A method of fabricating metal wiring for a semiconductor device according to claim 13, wherein the conductive region comprises doped silicon and wherein said step of forming an ohmic layer comprises the steps of:

depositing a tungsten nitride layer on the conductive layer exposed by the contact hole; and

forming an ohmic layer of tungsten silicide by thermally treating the tungsten nitride layer and the conductive layer so that tungsten of the tungsten nitride layer reacts with silicon of the conductive layer to produce a tungsten silicide layer.

17. A method of fabricating metal wiring for a semiconductor device according to claim 13, wherein the conductive region is formed of silicon doped with P⁺ impurities.

18. A method of fabricating metal wiring for a semiconductor device according to claim 13, wherein the conductive region is formed of a material selected from the group consisting of aluminum (Al), tungsten (W), molybdenum (Mo), cobalt (Co), titanium (Ti), copper (Cu), platinum (Pt), a silicide compound of aluminum (Al), tungsten (W), molybdenum (Mo), cobalt (Co), titanium (Ti), copper (Cu) and platinum (Pt), and an alloy of aluminum (Al), tungsten (W), molybdenum (Mo), cobalt (Co), titanium (Ti), copper (Cu) and platinum (Pt).

19. A method of fabricating metal wiring for a semiconductor device according to claim 13, wherein the insulating layer is formed of a material selected from the group consisting of silicon oxide, silicon nitride, doped silicon oxide and doped silicon nitride.

20. A method of fabricating metal wiring for a semiconductor device according to claim 13, wherein the tungsten source gas is selected from the group consisting of WF₆ and WCl₆.

21. A method of fabricating metal wiring for a semiconductor device according to claim 13, wherein the nitrogen-containing gas is selected from the group consisting of N₂, NH₃, and methyl hydrazine.

22. A method of fabricating metal wiring for a semiconductor device according to claim 14, wherein the reducing agent gas is selected from the group consisting of H₂, SiH₄, SiH₂ Cl₂, and PH₃.

23. A method of fabricating metal wiring for a semiconductor device according to claim 15, wherein the flow rate of the reducing agent gas is from about 0 to about 500 times the flow rate of the tungsten source gas.

24. A method of fabricating metal wiring for a semiconductor device according to claim 13, wherein the metal layer is formed of a material selected from the group consisting of aluminum (Al), tungsten (W), molybdenum (Mo), cobalt (Co), titanium (Ti), copper (Cu), platinum (Pt), a silicide compound of aluminum (Al), tungsten (W), molybdenum (Mo), cobalt (Co), titanium (Ti), copper (Cu) and platinum (Pt), and an alloy of aluminum (Al), tungsten (W), molybdenum (Mo), cobalt (Co), titanium (Ti), copper (Cu) and platinum (Pt).