System and method for metal residue detection and mapping within a multi-step sequence

• US 20040058620A1
• Filed: 09/19/2002
• Published: 03/25/2004
• Est. Priority Date: 09/19/2002
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Lam Research Corporation
• Inventors: Kistler, Rodney, Gotkis, Yehiel, Bright, Nicolas, Owczarz, Aleksander, Hemker, David
• Granted Patent: US 6,929,531 B2
• Time in Patent Office: Days
• US Class Current: 451/5
• CPC Class Codes: B24B 37/042 operating processes therefor
• CPC Class Codes: B24B 49/02 according to the instantaneous size and required size of the workpiece acted upon, the measuring or gauging being continuous or intermittent B24B49/12 takes precedence
• CPC Class Codes: B24B 49/10 involving electrical means B24B49/02, B24B49/08 take precedence
• CPC Class Codes: H01L 21/3212 by chemical mechanical polishing [CMP]
• CPC Class Codes: H01L 22/00 Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor

Abstract

A system and method of measuring a metallic layer on a substrate within a multi-step substrate process includes modifying a metallic layer on the substrate such as forming a metallic layer or removing at least a portion of the metallic layer. At least one sensor is positioned a predetermined distance from the surface of the substrate. The surface of the substrate is mapped to determine a uniformity of the metallic layer on the surface of the substrate.

Claims

1. A method of detecting metallic residue on a wafer within a CMP tool comprising:

applying a polishing pad to a surface of a wafer to substantially remove a metal layer;

moving the wafer away from the polishing pad;

positioning at least one sensor a predetermined distance from the surface of the wafer; and

mapping the surface of the wafer to determine if a metallic residue remains on the surface of the wafer.

2. The method of claim 1, wherein if metallic residue remains on the surface of the wafer then:

determining a location and a thickness of the metallic residue; and

applying the polishing pad to the surface of the wafer to substantially remove the metallic residue.

3. The method of claim 1, wherein the at least one sensor includes at least one eddy current sensor.

4. The method of claim 1, further comprising modifying at least one CMP tool operating parameter according to at least one of a location and a thickness of the metallic residue so as to optimize a subsequent CMP process on a subsequent wafer.

5. The method of claim 1, wherein applying the polishing pad to the surface of the wafer to substantially remove the metallic residue includes modifying at least one CMP tool operating parameter according to at least one of a location and a thickness of the metallic residue to optimize the removal of the metallic residue on the wafer.

6. The method of claim 1, wherein positioning includes aligning on at least two points on the wafer carrier.

7. The method of claim 1, wherein positioning includes moving the sensor in a radial motion.

8. The method of claim 1, wherein positioning includes moving the sensor in a linear motion.

9. The method of claim 1, wherein mapping includes moving at least one of the wafer carrier and the at least one sensor.

10. The method of claim 1, wherein the predetermined distance is determined by at least one distance sensor.

11. The method of claim 1, further comprising providing a permalloy layer between the wafer and the wafer carrier.

12. The method of claim 1, wherein mapping can include

scanning the entire surface of the wafer with the at least one sensor;

and

determining a thickness of the metallic residue that corresponds to an amplitude of a mapping signal.

13. A system for processing a substrate, comprising:

a movable substrate carrier, the substrate carrier configured to support the substrate during processing operations; and

at least one sensor that can be placed in parallel with and at a predetermined distance from a processed surface of the substrate, the at least one sensor capable of detecting a metallic layer on the processed surface of the substrate.

14. The system of claim 13, wherein the at least one sensor includes at least one eddy current sensor.

15. The system of claim 13, further comprising a permalloy layer located between the substrate and the substrate carrier.

16. The system of claim 15, wherein the permalloy layer has a thickness greater than a skin depth.

17. The system of claim 13, further comprising a distance sensor capable of detecting the predetermined distance.

18. The system of claim 13, the at least one sensor is movable and is capable of scanning substantially the entire processed surface of the substrate.

19. The system of claim 17, wherein the at least one sensor is movable in a radial motion.

20. The system of claim 13, further comprising a sensor carrier that is configured to support the at least one sensor, the sensor carrier being capable of being aligned with the substrate carrier at at least one point to determine the predetermined distance.

21. The system of claim 13, wherein the system for processing a substrate includes a chemical mechanical planarization (CMP) tool, and wherein the substrate includes a wafer.

22. The system of claim 13, wherein the system for processing a substrate further includes a system controller capable of controlling at least one process parameter and in communication with the at least one sensor.

23. A chemical mechanical planarization (CMP) tool comprising:

a movable wafer carrier defined within a housing, the wafer carrier configured to support a wafer during CMP operations;

at least one eddy current sensor located such that the at least one eddy current sensor can be placed in parallel with and at a predetermined distance from a planarized surface of the wafer, the at least one eddy current sensor capable of detecting a metallic residue on the planarized surface of the wafer; and

a permalloy layer located between the wafer and the wafer carrier.

24. A method of measuring a metallic layer on a substrate within a multi-step substrate process comprising:

modifying a metallic layer on the substrate;

positioning at least one sensor a predetermined distance from the surface of the substrate; and

mapping the surface of the substrate to determine a uniformity of the metallic on the surface of the substrate.

25. The method of claim 24, wherein modifying the metallic layer on the substrate includes forming the metallic layer on the substrate.

26. The method of claim 24, wherein modifying the metallic layer on the substrate includes removing at least a portion of the metallic layer from the substrate.