Method of fabricating contact plug

• US 6,706,626 B2
• Filed: 07/24/2002
• Issued: 03/16/2004
• Est. Priority Date: 04/16/2002
• Status: Active Grant

• Current Assignee: Macronix International Co., Ltd.
• Original Assignee: Macronix International Co., Ltd.
• Inventors: Huang, Chi-Tung
• Primary Examiner(s): NGUYEN, THANH T
• Application Number:
  US10/064,525
• Publication Number:
  US 20030194859A1
• Time in Patent Office: 601 Days
• Field of Search: 438/618, 438/621-630, 438/637-640, 438/643-645, 438/648-649, 438/652-656, 438/660, 438/663-664, 438/672, 438/678, 438/681, 438/682-683, 438/685, 438/687-688
• US Class Current: 438/653
• CPC Class Codes: H01L 21/76846 Layer combinations
• CPC Class Codes: H01L 21/76855 After-treatment introducing at least one additional element into the layer
• CPC Class Codes: H01L 21/76862 Bombardment with particles, e.g. treatment in noble gas plasmas; UV irradiation

Abstract

A method for manufacturing contact plug is disclosed. A dielectric layer is formed over a substrate having a conductive region. A contact opening is formed in the dielectric layer and exposing the conductive region within the opening. A first refractory metal layer is formed over the dielectric layer, and the sidewalls and bottom of the contact opening. A first refractory metal nitride layer is formed on the first refractory metal layer. A first plasma treatment step is carried out to transform the first refractory metal nitride layer into a first metal nitrided barrier layer. A thermal-process is carried out to form metal silicide on the conductive region. A second refractory metal nitride layer is formed on the first metal nitride barrier layer. A second plasma treatment step is carried out to transform the second refractory metal nitride layer into a second metal nitrided barrier layer. A conductive metal layer is deposited over the resulting structure and then the top surface is planarized to remove portions of the conductive metal layer, the second metal nitride barrier layer, the first metal nitride barrier layer, and the first refractory metal layer until the dielectric layer is exposed.

Claims

1. A method for fabricating contact plug, the method comprising the steps of:

providing a semiconductor substrate having a conductive region formed thereon;

forming a dielectric layer over the substrate;

forming a contact opening in the dielectric layer, wherein the conductive region is exposed within the contact opening;

forming a first refractory metal layer over the dielectric layer and the contact opening;

forming a first refractory metal nitride layer on the first refractory metal layer, wherein the first refractory metal nitride layer is formed by performing a metalorganic chemical deposition method;

performing a first plasma treatment to transform the first refractory metal nitride layer into a first metal nitrided barrier layer;

performing a thermal-process to trigger a reaction between the first refractory metal layer and the silicon atoms in the conductive region to form a metal silicide on the conductive region;

forming a second refractory metal nitride layer on the first metal nitrided barrier layer, wherein the second refractory metal nitride layer is formed by performing a metalorganic chemical deposition method;

performing a second plasma treatment to transform the second refractory metal nitride layer into a second metal nitrided barrier layer; and

forming a conductive layer over the second metal barrier layer to fill the contact opening.

2. The method according to claim 1, wherein the thermal process comprises a rapid-thermal-process (RTP).

3. The method according to claim 2, the RTP is carried out at a temperature of 550°

C. to 700°

C. and for a duration of 3-180 seconds.

4. The method according to claim 1, wherein the first and the second plasma treatment comprises plasma gas including nitrogen and hydrogen.

5. The method of claim 1, wherein the thickness of the first and the second refractory metal nitride layers is 120-160 angstroms.

6. The method of claim 1, wherein the thickness of the first and the second metal nitride barrier layers is 40-60 angstroms.

7. The method according to claim 1, wherein before the step of the forming the first refractory metal layer further comprises a pre-cleaning step.

8. The method according to claim 6, wherein the pre-cleaning step use a plasma gas containing argon gas.

9. The method according to claim 1, wherein the material of the conductive layer is selected from a group consisting of copper, aluminum and tungsten and alloys thereof.

10. The method according to claim 1, wherein the material of the second and third refractory metal nitride layer comprises of titanium nitride or tantalum nitride.

11. The method according to claim 1, wherein the conductive region is selected form a group consisting of a doped region, a silicon-based gate structure and silicon-based conductive line.

12. A method for fabricating contact plug, the method comprising the steps of:

providing a semiconductor substrate having a conductive region formed thereon;

forming a dielectric layer over the substrate;

forming a contact opening in the dielectric layer, wherein the conductive region is exposed within the contact opening;

forming a first refractory metal layer over the dielectric layer and the contact opening;

forming a multi-layered metal nitride barrier layer, wherein the multi-layered metal nitride barrier layer is formed by performing a multiple cycle of depositing a first refractory metal nitride layer and then performing a first plasma gas treatment, wherein the first refractory metal nitride layer is deposited by performing a metalorganic chemical deposition process;

performing a thermal-process to trigger a reaction between the first refractory metal layer and the silicon atoms in the conductive region to form a metal silicide on the conductive region;

forming a second refractory metal nitride layer on the multi-layered metal nitride barrier layer, wherein the second refractory metal nitride layer is formed by performing a metalorganic chemical deposition method;

performing a second plasma treatment to transform the second refractory nitride metal layers into a metal nitride barrier layer; and

forming a conductive layer over the metal nitride barrier layer filling contact opening.

13. The method according to claim 12, wherein the thermal process comprises a rapid-thermal-process (RTP).

14. The method according to claim 12, wherein the RTP is carried out at a temperature of 550 to 700°

C. and for a duration of 3-180 seconds.

15. The method according to claim 12, wherein the first and the second plasma treatment comprises a plasma gas including nitrogen and hydrogen.

16. The method according to claim 12, wherein the material of the conductive layer is selected from a group consisting of copper, aluminum and tungsten and alloys thereof.

17. The method according to claim 12, wherein the material of the first and the second refractory metal nitride layers comprises of titanium nitride or tantalum nitride.

18. The method according to claim 12, wherein the conductive region is selected from a group consisting of a doped region, a silicon-based gate structure and a silicon-based conductive line.