Polishing apparatus and wear detection method

Patent metadata

Field	Value
Publication number	US-9530704-B2
Application number	US-201514836518-A
Country	US
Kind code	B2
Filing date	Aug 26, 2015
Priority date	Mar 29, 2013
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

There is provided a polishing apparatus capable of detecting uneven wear occurring on a polishing pad and detecting an appropriate replacement timing of the polishing pad. The polishing apparatus detects, every predetermined time, a value of rotation speed or a value of rotation torque of a table drive shaft for rotationally driving a polishing table or a dresser drive shaft for driving a dresser, or a value of swing torque of a dresser swing shaft for driving the dresser; calculates a change quantity thereof based on the value of the detected rotation speed, the value of the detected rotation torque, or the value of the detected swing torque; determines whether or not the change quantity exceeds a predetermined value; and notifies a user of a warning when a determination is made that the change quantity exceeds the predetermined value.

First claim

What is claimed is:

1. A CMP apparatus having a detecting system of uneven wear of a polishing pad, comprising:
a rotatable polishing table for disposing a polishing pad thereon, connected to a table drive shaft for rotation;
a rotatable polishing head configured to hold and press a substrate against the polishing pad;
a dressing device comprising,
a rotatable dressing head having a dressing surface for dressing a polishing surface of the polishing pad, and connected to a dresser drive shaft to rotate the dressing head, and
a dresser swing shaft connected to a swing actuator, and configured to move the dressing head between positions above the polishing table and outside the polishing table; and

a detecting system for detecting an uneven wear of the polishing pad, comprising,
a sensor device to detect at least one of
a rotational speed of the polishing table,
a rotational torque applied to the polishing table by the table drive shaft,
a rotational speed of the dresser head,
a rotational torque applied to the dresser head by the dresser drive shaft, and
a swing torque applied to the dresser swing shaft by the swing actuator, and

a controller configured to receive each detected data from the sensor device, calculate a variation of the each detected data in a first predetermined period of time, and determine whether the calculated variation exceeds a first set of predetermined values to detect an uneven wear of the polishing pad.

2. The CMP apparatus according to claim 1 , wherein
the controller is configured to
receive the each detected data from the sensor device,
average the each detected data by averaging consecutive data of a second predetermined period of time,
calculate the variation(s) of the averaged detected data, and
determine whether the calculated variation(s) exceeds the first set of predetermined values to detect an uneven wear of the polishing pad.

3. The CMP apparatus according to claim 2 , wherein
the controller is configured to average the detected data using root mean square method.

4. The CMP apparatus according to 1 , wherein
the sensor device detects the rotational speed of the dresser head and the rotational torque applied to the dresser head by the dresser drive shaft.

5. The CMP apparatus according to claim 4 , wherein
the controller is configured to
receive the each detected data from the sensor device,
average the each detected data by averaging consecutive data of a predetermined number,
obtain the variation of the averaged detected data, and
determine whether the calculated variation exceeds the first set of predetermined values to detect an uneven wear of the polishing pad.

6. The CMP apparatus according to claim 1 , wherein
the controller sends a warning signal when the controller determines that the variation(s) exceeds the first predetermined value.

7. The CMP apparatus according to claim 1 , wherein
the controller is configured to start receiving the detected data from the sensor device at a predetermined period of time after the dressing device starts dressing.

8. The CMP apparatus according to claim 1 , wherein
the controller is configured to
receive each detected data from the sensor device,
obtain a variation of the each detected data in a first predetermined period of time,
determine whether the calculated variation exceeds a first set of predetermined values to detect an uneven wear of the polishing pad,
count a number of times in which the variation exceeds the first set of predetermined values for a second predetermined period of time, and
send a warning if the number exceeds a second predetermined number.

9. A method for detecting uneven wear of a polishing pad placed on a polishing table of a polishing apparatus, the method comprising:
providing a polishing apparatus having a polishing table with a polishing pad thereon, and a dressing head having a dressing surface and connected to a dresser swing shaft,
rotating the polishing pad with the polishing table,
rotating the dressing surface of the dressing head,
dressing the polishing pad by pressing the rotating dressing surface of the dressing head against the rotating polishing pad,
swinging the dressing head on the polishing pad with the dresser swing shaft,
detecting by a sensor device at least one of
a rotational speed of the polishing table,
a rotational torque applied to the polishing table,
a rotational speed of the dresser head,
a rotational torque applied to the dresser head, and
a swing torque applied to the dresser swing shaft,

receiving the detected data by a controller from the sensor device,
obtaining a variation of the detected data of a predetermined period of time by the controller, and
determining by the controller whether the calculated variation exceeds a first predetermined value to detect an uneven wear of the polishing pad.

10. The method according to claim 9 , further comprising:
receiving the each detected data by the controller from the sensor device,
averaging the each detected data by averaging consecutive data of a second predetermined period of time by the controller,
calculating the variation(s) of the averaged detected data by the controller, and
determine by the controller whether the calculated variation(s) exceeds the first set of predetermined values to detect an uneven wear of the polishing pad.

11. The method according to claim 10 , wherein
averaging the each detected data includes averaging the detected data using root mean square method.

12. The method according to claim 9 , further comprising:
detecting by the sensor device the rotational speed of the dresser head and the rotational torque applied to the dresser head by the dresser drive shaft.

13. The method according to claim 12 , further comprising:
receiving the each detected data by the controller from the sensor device,
averaging the each detected data by averaging consecutive data of a predetermined number by the controller,
obtaining the variation of the averaged detected data by the controller, and
determine by the controller whether the calculated variation exceeds the first set of predetermined values to detect an uneven wear of the polishing pad.

14. The method according to claim 9 , further comprising:
sending a warning signal when the controller determines that the variation(s) exceeds the first predetermined value.

15. The method according to claim 9 , further comprising:
receiving the detected data by the controller from the sensor device at a predetermined period of time after the dressing device starts dressing.

16. The method according to claim 9 , further comprising:
receiving each detected data by the controller from the sensor device,
obtaining a variation of the each detected data in a first predetermined period of time by the controller,
determining by the controller whether the calculated variation exceeds a first set of predetermined values to detect an uneven wear of the polishing pad,
counting by the controller a number of times in which the variation exceeds the first set of predetermined values for a second predetermined period of time, and
sending a warning if the number exceeds a second predetermined number.

Assignees

• Ebara Corp

Inventors

• Kosuge Ryuichi
• Sone Tadakazu

Classifications

• H10P72/0422

  for wet etching · CPC title

• H10P52/402

  of semiconductor materials · CPC title

• H10P74/238 Primary

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

• B24B49/00

  Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation (B24B33/06, B24B37/005 take precedence; if applicable to other machine tools, B23Q15/00 - B23Q17/00 take precedence) · CPC title

• B24B53/017

  Devices or means for dressing, cleaning or otherwise conditioning lapping tools · CPC title