OPTICAL MARKER LAYER FOR ETCH ENDPOINT DETERMINATION

• US 20020192845A1
• Filed: 06/14/2001
• Published: 12/19/2002
• Est. Priority Date: 06/14/2001
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Xia, Li-Qun, Kim, Yunsang, Yieh, Ellie, Nguyen, Huong Thanh
• Granted Patent: US 6,511,920 B2
• Time in Patent Office: Days
• US Class Current: 438/9
• CPC Class Codes: H01L 21/76813 involving a partial via etch
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76829 characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers
• CPC Class Codes: H01L 21/76832 Multiple layers
• CPC Class Codes: H01L 22/24 Optical enhancement of defects or not directly visible states, e.g. selective electrolytic deposition, bubbles in liquids, light emission, colour change voltage contrast G01R31/311
• CPC Class Codes: Y10S 438/931 Silicon carbide semiconductor

Abstract

A method of forming an optical marker layer for etch endpoint determination in integrated circuit fabrication processes is disclosed. The optical marker layer is used in conjunction with organic and/or carbon-containing material layers that are used as bulk insulating materials and barrier materials. The optical marker layer is formed on the bulk insulating material layer and/or the barrier material layer by incorporating an optical marker into the surface thereof. The optical marker is incorporated into the surface of the bulk insulating material layer and/or the barrier material layer by treating such layer with an optical marker-containing gas. The optical marker layer provides an optical marker emission spectrum when it is etched during a subsequent patterning step.

Claims

1. A method of forming an optical marker layer for etch endpoint determination, comprising:

forming a first carbon-containing layer on a substrate;

forming an optical marker layer on the first carbon-containing layer by positioning the substrate in a process chamber, providing an optical marker-containing atmosphere to the process chamber, and treating the first carbon-containing layer with the optical marker-containing atmosphere to incorporate the optical marker therein; and

forming a second carbon-containing layer on the optical marker layer.

2. The method of claim 1 wherein the first carbon-containing layer and the second carbon-containing layer each comprise an organosilicate material or silicon carbide.

3. The method of claim 1 wherein the optical marker-containing atmosphere includes a gas mixture comprising one or more gases selected from the group consisting of ammonia (NH₃), nitrogen (N₂), oxygen (O₂), argon (Ar), and helium (He).

4. The method of claim 1 wherein the process chamber is maintained at a temperature within a range of about 50°

C. to about 400°

C.

5. The method of claim 1 wherein the process chamber is maintained at a pressure within a range of about 1 torr to about 10 torr.

6. The method of claim 3 wherein the optical marker-containing atmosphere comprises a plasma.

7. The method of claim 6 wherein the plasma is generated by applying an electric field to the gas mixture in the process chamber.

8. The method of claim 7 wherein the electric field is a radio frequency (RF) power.

9. The method of claim 8 wherein the RF power is within a range of about 1 watt/cm² to about 100 watts/cm².

10. The method of claim 1 wherein the first carbon-containing layer is treated for less than about 100 seconds.

11. The method of claim 1 wherein the optical marker layer has a thickness of about 100 Å

to about 200 Å

.

13. The method of claim 12 wherein the optical marker layer is used to determine the etch endpoint when the vias are defined in the second carbon-containing layer.

14. The method of claim 12 wherein the conductive material filling the vias and interconnects is selected from the group of copper (Cu), aluminum (Al), tungsten (W), and combinations thereof.

15. The method of claim 12 wherein the first carbon-containing layer and the second carbon-containing layer each comprise an organosilicate material or silicon carbide.

16. The method of claim 12 wherein the optical marker-containing atmosphere comprises a gas mixture including one or more gases selected from the group consisting of ammonia (NH₃), nitrogen (N₂), oxygen (O₂), argon (Ar), and helium (He).

17. The method of claim 12 wherein the process chamber is maintained at a temperature within a range of about 50°

C. to about 400°

C.

18. The method of claim 12 wherein the process chamber is maintained at a pressure within a range of about 1 torr to about 10 torr.

19. The method of claim 16 wherein the optical marker-containing atmosphere comprises a plasma.

20. The method of claim 19 wherein the plasma is generated by applying an electric field to the gas mixture in the process chamber.

21. The method of claim 20 wherein the electric field is a radio frequency (RF) power.

22. The method of claim 21 wherein the RF power is within a range of about 1 watt/cm² to about 100 watts/cm².

23. The method of claim 12 wherein the first carbon-containing layer is treated for less than about 100 seconds.

24. The method of claim 12 wherein the optical marker layer has a thickness of about 100 Å

to about 200 Å

.

26. The method of claim 25 wherein the optical marker layer is used to determine the etch endpoint when the vias are defined in the second carbon-containing layer.

12. A method of fabricating a damascene structure, comprising:

(a) forming a barrier layer on a substrate having a metal layer thereon;

(b) forming a first carbon-containing layer on the barrier layer;

(c) forming an optical marker layer on the first carbon-containing layer by positioning the substrate in a process chamber, providing an optical marker-containing atmosphere to the process chamber, and treating the first carbon-containing layer with the optical marker-containing atmosphere to incorporate the optical marker therein;

(d) forming a second carbon-containing layer on the optical marker layer;

(e) patterning the second carbon-containing layer to define vias therein;

(f) patterning the second carbon-containing layer to define interconnects therethrough, wherein the interconnects are positioned over the vias, and wherein the via pattern is transferred through the first carbon-containing layer when the interconnects are defined in the second carbon-containing layer; and

(g) filling the vias and interconnects with a conductive material.

25. A method of fabricating a damascene structure, comprising:

(a) forming a first barrier layer on a substrate having a metal layer thereon;

(b) forming a first carbon-containing layer on the first barrier layer;

(c) forming a second barrier layer on the first carbon-containing layer;

(d) forming an optical marker layer on the second barrier layer by positioning the substrate in a process chamber, providing an optical marker-containing atmosphere to the process chamber, and treating the second barrier layer with the optical marker-containing atmosphere to incorporate the optical marker therein;

(e) forming a second carbon-containing layer on the optical marker layer;

(f) patterning the second carbon-containing layer to define vias therein;

(g) patterning the second carbon-containing layer to define interconnects therethrough, wherein the interconnects are positioned over the vias, and wherein the via pattern is transferred through both the second barrier layer and the first carbon-containing layer when the interconnects are defined in the second carbon-containing layer; and

(h) filling the vias and interconnects with a conductive material.