Process for polishing and analyzing an exposed surface of a patterned semiconductor

• US 5,691,253 A
• Filed: 06/05/1995
• Issued: 11/25/1997
• Est. Priority Date: 06/02/1994
• Status: Expired due to Term

• Current Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Kobayashi, Thomas S.
• Primary Examiner(s): Tsai, Jey
• Application Number:
  US08/462,477
• Time in Patent Office: 904 Days
• Field of Search: 437/228, 437/225, 437/173, 156/636.1, 156/626.1
• US Class Current: 439/690
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• 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: G01B 11/028 by measuring lateral position of a boundary of the object G01B11/022, G01B11/024, G01B11/04 take precedence
• CPC Class Codes: G01B 11/303 using photoelectric detection means

Abstract

A layer over a patterned semiconductor is polished and analyzed to determine a polishing endpoint. The analysis may be performed using reflected radiation beams or by a radiation scattering analyzer. The analysis may be performed on virtually any layer using a radiation source. The analysis may be performed with a liquid, such as an aqueous slurry, contacting the substrate. The polishing and analysis may be integrated such that both steps are performed on the same polisher.

Claims

1. A process for polishing a layer over a patterned semiconductor substrate comprising the steps of:

forming the layer over the patterned semiconductor substrate, wherein the layer has a first exposed surface that lies at a first elevation and a second elevation that is different from the first elevation and has a first edge that lies between the first and second elevations;

polishing the layer to form a second exposed surface; and

analyzing the second exposed surface with a radiation beam wherein the step of polishing is repeated if the radiation beam is reflected by the first edge.

2. The process of claim 1, wherein step of analyzing is performed while a liquid contacts the second exposed surface.

3. The process of claim 1, wherein the radiation beam is generated by a laser.

4. The process of claim 1, wherein the step of analyzing forms an output that does not include information related to direction and magnitude of topography changes along the second exposed surface.

5. The process of claim 1, wherein the layer is transparent to the radiaiton beam.

6. The process of claim 1, wherein the layer is opaque to the radiation beam.

17. The process of claim 1, wherein the step of analyzing is performed using a radiation scattering analyzer.

18. The process of claim 1, wherein the steps of polishing and analyzing are performed in a polisher.

19. The process of claim 6, wherein:

the patterned semiconductor substrate has a surface lying near the layer, lying at a third elevation, and lying a fourth elevation;

a second edge lying between the third and fourth elevations; and

the step of polishing is not repeated if the radiation beam is reflected by the second edge during the step of analyzing.

7. A process for polishing a layer over a patterned semiconductor substrate comprising the steps of:

forming the layer over the patterned semiconductor substrate, wherein;

the patterned semiconductor substrate has a substrate surface that lies at a plurality of substrate elevations, wherein substrate edges lie between different elevations within the plurality of substrate elevations;

the layer has a first exposed surface that lies at a first elevation and a second elevation that is different from the first elevation, wherein a first edge lies between the first and second elevations;

polishing the layer to form a second exposed surface having a second topography; and

analyzing the second exposed surface with a radiation beam to form an output, wherein the step of polishing is repeated until only the substrate edges, and not the first edge, are detected in the output.

8. The process of claim 7, wherein step of analyzing the second exposed surface is performed while a liquid contacts the second exposed surface.

9. The process of claim 7, wherein the radiation beam is generated by a laser.

10. The process of claim 7, wherein the step of polishing is repeated if the first edge is detected in the output.

20. The process of claim 7, wherein the step of analyzing is performed using a radiation scattering analyzer.

21. The process of claim 7, wherein the layer is transparent to the radiation beam.

22. The process of claim 7, wherein the layer is opaque to the radiation beam.

23. The process of claim 22, wherein:

the substrate edges cannot be detected between the steps of forming and polishing the layer; and

the step of polishing is performed until only the substrate edges are detected in the output.

24. The process of claim 7, wherein the output does not include information related to direction and magnitude of topography changes along the second exposed surface.

25. The process of claim 7, wherein the steps of polishing and analyzing are performed in a polisher.

11. A process for polishing a layer over a patterned semiconductor substrate comprising the steps of:

forming the layer over the patterned semiconductor substrate, wherein the layer has a first exposed surface;

polishing the layer to form a second exposed surface with a slurry having slurry particles;

analyzing the second exposed surface at a location with a radiation beam, wherein this step is performed while particles are present at the location; and

drying the patterned semiconductor substrate after the step of analyzing.

12. The process of claim 11, wherein the step of analyzing is performed after the step of polishing and before the step of drying.

13. The process of claim 11, further comprising a step of removing slurry particles between the steps of analyzing and drying.

14. The process of claim 11, wherein the step of analyzing is performed while a liquid contacts the layer.

15. The process of claim 11, wherein the steps of polishing and analyzing are performed while water contacts the layer.

16. The process of claim 11, wherein the steps of polishing and analyzing are performed in a polisher.