Core configuration for in-situ electromagnetic induction monitoring system

Patent metadata

Field	Value
Publication number	US-11638982-B2
Application number	US-201916533500-A
Country	US
Kind code	B2
Filing date	Aug 6, 2019
Priority date	Oct 21, 2016
Publication date	May 2, 2023
Grant date	May 2, 2023

Abstract

An apparatus for chemical mechanical polishing includes a support for a polishing pad having a polishing surface, and an electromagnetic induction monitoring system to generate a magnetic field to monitor a substrate being polished by the polishing pad. The electromagnetic induction monitoring system includes a core and a coil wound around a portion of the core. The core includes a back portion, a center post extending from the back portion in a first direction normal to the polishing surface, and an annular rim extending from the back portion in parallel with the center post and surrounding and spaced apart from the center post by a gap. A width of the gap is less than a width of the center post, and a surface area of a top surface of the annular rim is at least two times greater than a surface area of a top surface of the center post.

First claim

What is claimed is:

1. An apparatus for chemical mechanical polishing, comprising:
a support for a polishing pad having a polishing surface; and
an electromagnetic induction monitoring system to generate a magnetic field to monitor a substrate being polished by the polishing pad, the electromagnetic induction monitoring system comprising a core and a coil wound around a portion of the core, the core including
a back portion,
a center post extending from the back portion in a first direction normal to the polishing surface, and
an annular rim extending from the back portion in parallel with the center post and surrounding and spaced apart from the center post by a gap, wherein a surface area of a top surface of the annular rim is three to six times greater than a surface area of a top surface of the center post.

2. The apparatus of claim 1 , wherein the center post has a first width in a second direction parallel to the polishing surface, the annular rim has a second width in the second direction, and the gap has a third width in the second direction, and wherein the third width is less than the first width.

3. The apparatus of claim 2 , wherein the third width is 50% to 75% of the first width.

4. The apparatus of claim 2 , wherein the second width is greater than the first width.

5. The apparatus of claim 2 , wherein the third width is between about 30% and 70% of the second width.

6. The apparatus of claim 1 , wherein a height of the center post is equal to a height of the annular rim.

7. The apparatus of claim 1 , wherein the center post is circular and the annular rim is cylindrical.

8. The apparatus of claim 1 , wherein the coil and core are configured to provide a resonant frequency of 50 kHz to 50 MHz.

9. The apparatus of claim 8 , wherein the coil and core are configured to provide a resonant frequency between about 14 and 16 MHz.

10. An apparatus for chemical mechanical polishing, comprising:
a support for a polishing pad having a polishing surface; and
an electromagnetic induction monitoring system to generate a magnetic field to monitor a substrate being polished by the polishing pad, the electromagnetic induction monitoring system comprising a core and an annular winding assembly,
wherein the core includes a back portion, a center post extending from the back portion in a first direction normal to the polishing surface, and an annular rim extending from the back portion in parallel with the center post and surrounding the center post and spaced apart from the center post by a gap,
and wherein the winding assembly fits in the gap between the center post and the annular rim and includes a bobbin in contact with an outer surface of the center post and a coil wound around the bobbin.

11. The apparatus of claim 10 , wherein the bobbin is plastic.

12. The apparatus of claim 10 , wherein the bobbin includes a cap that rests against a top surface of the center post.

13. The apparatus of claim 10 , wherein the center post has a first width in a second direction parallel to the polishing surface, the annular rim has a second width in the second direction, the gap has a third width in the second direction, and the winding assembly has a fourth width between an inner diameter and an outer diameter of a cylindrical body of the winding assembly, and wherein the fourth width is at least 80% of the third width.

14. The apparatus of claim 13 , wherein an inner surface of the bobbin provides the inner diameter of the winding assembly.

15. The apparatus of claim 10 , wherein the winding assembly includes a tape contacting and surrounding the coil, and an outer surface of the tape provides an outer diameter of the winding assembly.

16. The apparatus of claim 15 , wherein the outer surface of the tape contacts an inner surface of the annular rim.

17. The apparatus of claim 10 , wherein the coil comprises no more than two winding layers around the bobbin.

18. The apparatus of claim 13 , wherein the fourth width is at least 90% of the third width.

Assignees

• Applied Materials Inc

Inventors

• Iravani Hassan G
• Xu Kun
• Ivanov Denis
• Shen Shih-Haur
• Swedek Boguslaw A

Classifications

• H10P74/238

  comprising acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection or in-situ thickness measurement · CPC title

• H10P74/207

  Electrical properties, e.g. testing or measuring of resistance, deep levels or capacitance-voltage characteristics · CPC title

• B24B49/105 Primary

  using eddy currents · CPC title

• B24B49/045 Primary

  Specially adapted gauging instruments · CPC title

• B24B37/013

  Devices or means for detecting lapping completion · CPC title