METHOD TO IMPROVE WITHIN WAFER UNIFORMITY OF CMP PROCESS

• US 20140015107A1
• Filed: 07/12/2012
• Published: 01/16/2014
• Est. Priority Date: 07/12/2012
• Status: Abandoned Application

• Current Assignee: Macronix International Co., Ltd.
• Original Assignee: Macronix International Co., Ltd.
• Inventors: Chen, Chun-Fu, Su, Chin-Ta, Chen, Ching-Kun
• Application Number:
  US13/547,333
• Publication Number:
  US 20140015107A1
• Time in Patent Office: Days
• US Class Current: 257/618
• CPC Class Codes: B24B 37/015 Temperature control
• CPC Class Codes: H01L 21/3212 by chemical mechanical polishing [CMP]
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32

Abstract

Closed loop control may be used to improve uniformity of within wafer uniformity using chemical mechanical planarization. For example, closed loop control may be used to determine a control profile for a chemical mechanical planarization process to more uniformly and consistently achieve the desired extent of variation of within wafer uniformity of a semiconductor wafer.

Claims

1. A system for controlling a thickness profile of a wafer comprising:

a control model;

a chemical mechanical planarization tool; and

at least one sensor,

wherein the control model receives the thickness profile of the wafer measured by the at least one sensor and determines a control profile for the chemical mechanical planarization tool.

2. The system of claim 1, wherein the control profile comprises a plurality of control variables for a polishing head of the chemical mechanical planarization tool.

3. The system of claim 2, wherein the plurality of control variables comprise a plurality of heat applied to a series of points across the polishing head.

4. The system of claim 2, wherein the plurality of control variables comprise a plurality of temperatures applied to a series of points across the polishing head.

5. The system of claim 1, wherein the chemical mechanical planarization tool is a metal chemical mechanical planarization tool and the thickness profile is a metal thickness profile.

6. The system of claim 5, wherein the metal chemical mechanical planarization tool is a copper chemical mechanical planarization tool and the metal thickness profile is a copper thickness profile.

7. The system of claim 5, wherein the metal chemical mechanical planarization tool is a tungsten chemical mechanical planarization tool and the metal thickness profile is a tungsten thickness profile.

8. A chemical mechanical planarization tool comprising a polishing head having a plurality of heat applied to a series of points across the polishing head, wherein the plurality of heat applied to the series of points is controlled to achieve a desired thickness profile of a wafer that is polished using the chemical mechanical planarization tool.

9. The chemical mechanical planarization tool of claim 8 additionally comprising a plurality of temperatures applied to the series of points across the polishing head, wherein the plurality of heat applied to the series of points determines a desired temperature profile.

10. The chemical mechanical planarization tool of claim 8 additionally comprising a plurality of pressures applied to another series of points across the polishing head, wherein the plurality of heat applied to the series of points and the plurality of pressures applied to the another series of points determines the desired thickness profile.

11. A method for controlling a thickness profile of a wafer, comprising:

specifying a target for the thickness profile;

measuring the thickness profile of the wafer;

determining a control profile for a chemical mechanical planarization process using the measured thickness profile, the target, and a control model;

applying the control profile to the chemical mechanical planarization process; and

polishing the wafer using the chemical mechanical planarization process and the applied control profile.

12. The method of claim 11, additionally comprising repeating the measuring, determining, and applying steps at periodic interval while continuing to apply the control profile to the chemical mechanical planarization process.

13. The method of claim 11, wherein the control profile comprises a plurality of heat applied to a series of points across a polishing head of the chemical mechanical planarization process.

14. The method of claim 11, wherein the chemical mechanical planarization process is a metal chemical mechanical planarization process and the thickness profile is a metal thickness profile.

15. The method of claim 14, wherein the metal chemical mechanical planarization process is a tungsten chemical mechanical planarization process and the metal thickness profile is a tungsten thickness profile.

16. The method of claim 11, further comprising:

measuring a starting thickness of the wafer and

adapting the at least one control variable using the measured starting thickness and the control model.

17. A wafer for a semiconductor fabricated by a process comprising:

specifying a target for the thickness profile;

measuring the thickness profile of the wafer;

determining a control profile for a chemical mechanical planarization process using the measured thickness profile, the target, and a control model;

applying the control profile to the chemical mechanical planarization process; and

polishing the wafer using the chemical mechanical planarization process and the applied control profile.

18. The wafer of claim 17, wherein the chemical mechanical planarization process is a metal chemical mechanical planarization tool and the thickness profile is a metal thickness profile.

19. The wafer of claim 18, wherein the metal chemical mechanical planarization process is one of a copper chemical mechanical planarization tool and the metal thickness is a copper thickness profile or a tungsten chemical mechanical planarization tool and the metal thickness profile is a tungsten thickness profile.

20. The wafer of claim 17, wherein the control profile comprises a plurality of heat applied to a series of points across a polishing head of the chemical mechanical planarization process.