Real time profile control for chemical mechanical polishing

Patent metadata

Field	Value
Publication number	US-10562148-B2
Application number	US-201715727288-A
Country	US
Kind code	B2
Filing date	Oct 6, 2017
Priority date	Oct 10, 2016
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

A method of controlling processing of a substrate includes generating, based on a signal from an in-situ monitoring system, first and second sequences of characterizing values indicative of a physical property of a reference zone and a control zone, respectively, on a substrate. A reference zone rate and a control zone rate are determined from the first and sequence of characterizing values, respectively. An error value is determined by comparing characterizing values for the reference zone and control zone. An output parameter value for the control zone is generated based on at least the error value and a dynamic nominal control zone value using a proportional-integral-derivative control algorithm, and the dynamic nominal control zone value is generated in a second control loop based on at least the reference zone rate and the control zone rate. The control zone of the substrate is processed according to the output parameter value.

First claim

What is claimed is:

1. A computer program product, tangibly embodied in a non-transitory computer readable media, comprising instructions for causing a processor to:
generate, based on a signal from an in-situ monitoring system, a first sequence of characterizing values indicative of a physical property of a reference zone on a substrate undergoing processing in a processing system and being monitored by the in-situ monitoring system;
generate, based on the signal from the in-situ monitoring system, a second sequence of characterizing values indicative of a physical property of a control zone on the substrate;
determine a reference zone rate from the first sequence of characterizing values;
determine a control zone rate from the second sequence of characterizing values;
determine an error value by comparing a characterizing value for the reference zone to a characterizing value for the control zone;
calculate, using a proportional-integral-derivative control algorithm, an output parameter value for the control zone in a first control loop based on at least i) the error value and ii) a dynamic nominal control zone value;
generate the dynamic nominal control zone value in a second control loop based on at least the reference zone rate and the control zone rate; and
cause the processing system to process the control zone using the output parameter value.

2. The computer program product of claim 1 , wherein the instructions to determine the error value comprise instructions to calculate a difference between the characterizing value for the reference zone and the characterizing value for the control zone.

3. The computer program product of claim 1 , wherein the instructions to determine the reference zone rate comprise instructions to fit a first function to the sequence of values for the reference zone and to determine a first slope of the first function, and wherein the instructions to determine the control zone rate comprise instructions to fit a second function to the sequence of values for the control zone and to determine a second slope of the second function.

4. The computer program product of claim 1 , wherein the instructions to calculate the output parameter value comprise instructions to calculate the parameter value u(t) according to

u
⁡

(
t
)

=

u
′

⁡

(
0
)

+

K
p

⁢

e
⁡

(
t
)

+

K
I

⁢

∫
0
t

⁢

e
⁡

(
t
)

⁢
dt

+

K
D

⁢

de
⁡

(
t
)

dt

where u′(0) is the dynamic nominal control zone value, e(t) is the error value, and K P , K I and K D are PID controller parameter constants.

5. The computer program product of claim 1 , wherein the instructions to generate the dynamic nominal control zone value comprise instructions to generate an error rate based on at least the reference zone rate and the control zone rate.

6. The computer program product of claim 5 , wherein the instructions to generate the error rate comprise instructions to calculate a rate set point value based on the reference zone rate.

7. The computer program product of claim 6 , wherein the instructions to calculate the rate set point value comprise instruction to calculate the rate set point value based on the error value, the reference zone rate and the control zone rate.

8. The computer program product of claim 7 , wherein the instructions to calculate a rate set point value comprise instructions to calculate the rate set point value r SP according to
r SP =r R ( t )−DSPW* R MAX

where r R (t) is the reference zone rate, R MAX is a predetermined constant, and DSPW is a dynamic set point weight.

9. The computer program product of claim 8 , comprising instruction to calculate the dynamic set point weight according to

DSPW
=

1
-

e

-
err

*
f

1
+

e

-
err

*
f

where err is the error value e(t) and f is a tuning value.

10. The computer program product of claim 6 , wherein the instructions to calculate the rate set point value comprise instruction to calculate the rate set point value based on the characterizing value for the reference zone, the characterizing value for the control zone, and the reference zone rate, and a target characterizing value.

11. The computer program product of claim 10 , wherein the instructions to calculate the rate set point value comprises instructions to calculate the rate set point value r SP according to the following:

r
SP

=

y
R

-

y
EP

y
c

-

y

Assignees

• Applied Materials Inc

Inventors

• Shen Shih-Haur
• Xu Kun
• Liu Tzu-Yu

Classifications

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• 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

• B24B51/00

  Arrangements for automatic control of a series of individual steps in grinding a workpiece (if applicable to other machine tools, G05B takes precedence) · CPC title

• B24B37/12

  Lapping plates for working plane surfaces · CPC title

• B24B49/105

  using eddy currents · CPC title