Method and apparatus for calibration of substrate temperature using pyrometer

Patent metadata

Field	Value
Publication number	US-11543296-B2
Application number	US-201916551128-A
Country	US
Kind code	B2
Filing date	Aug 26, 2019
Priority date	May 31, 2019
Publication date	Jan 3, 2023
Grant date	Jan 3, 2023

Abstract

A method may include heating a substrate in a first chamber to a platen temperature, the heating comprising heating the substrate on a platen; measuring the platen temperature in the first chamber using a contact temperature measurement; transferring the substrate to a second chamber after the heating; and measuring a voltage decay after transferring the substrate to the second chamber, using an optical pyrometer to measure pyrometer voltage as a function of time.

First claim

What is claimed is:

1. A method, comprising:
heating a substrate on a process platen in a first chamber, the process platen characterized by a platen temperature;
measuring the platen temperature in the first chamber using a contact temperature measurement;
transferring the substrate to a second chamber after the heating;
recording a zero time, the zero time corresponding to an instance when the transferring the substrate commences; and
measuring a temperature decay response after the zero time during a measurement interval, using an optical pyrometer, the measuring the temperature decay response comprising:
measuring a pyrometer voltage that is output by the optical pyrometer at a plurality of instances to generate a plurality of voltage data;
generating a voltage decay curve from the plurality of voltage data; and
extrapolating the voltage decay curve from the measurement interval to the zero time.

2. The method of claim 1 , the measuring the temperature decay response curve comprising fitting a polynomial function to the plurality of voltage data.

3. The method of claim 1 , the transferring comprising placing the substrate at a substrate position in the second chamber at a second instance, subsequent to the transfer instance, the method further comprising:
determining a zero-time pyrometer voltage by determining a pyrometer voltage corresponding to an intersection of the voltage decay curve at zero time with a horizontal line; and
mapping the zero-time pyrometer voltage to the platen temperature to generate a voltage-platen temperature data point.

4. The method of claim 1 , wherein the second chamber comprises a preheat station, the method further comprising:
placing the substrate in the preheat station before the heating the substrate in the first chamber; and
before the placing the substrate, prewarming the preheat station to a targeted prewarm temperature.

5. The method of claim 1 , wherein the heating the substrate in the first chamber, the
measuring the platen temperature in the first chamber, the transferring the substrate to a second chamber after the heating, and the measuring the voltage decay after transferring the substrate, comprising a first calibration cycle, the method further comprising:
performing at least one additional calibration cycle, wherein the platen temperature is increased between the first calibration cycle and the at least one additional calibration cycle.

6. The method of claim 5 , wherein the generating the voltage decay curve, the extrapolating the voltage decay curve to the zero time, and the determining the zero-time pyrometer voltage comprise a first calibration curve cycle, the method further comprising:
performing at least one additional calibration curve cycle, wherein the platen temperature is increased between the first calibration curve cycle and the at least one additional calibration curve cycle, wherein each calibration cycle of the first calibration cycle and the at least one additional calibration cycle generates a voltage-platen temperature data point; and
generating a calibration trend line comprising a plurality of voltage-platen temperature data points, based upon the first calibration cycle and at least one additional calibration cycle.

7. The method of claim 6 , further comprising:
recording a first substrate type for the substrate;
loading a process substrate into the second chamber;
heating the process substrate in the second chamber to a targeted temperature, using an experimental substrate temperature of the substrate recorded by an optical pyrometer, wherein the experimental substrate temperature is determined by:
outputting an experimental voltage, generated in the pyrometer by emission from the process substrate; and
mapping the experimental voltage to a corresponding substrate temperature on the calibration curve.

8. The method of claim 6 , further comprising:
determining, for a targeted temperature range, an offset between platen temperature and substrate temperature, when the substrate is disposed on the platen; and
generating a corrected calibration curve based upon the calibration curve and the offset.

9. A method comprising:
sending a heat signal to heat a substrate platen in a process chamber to a platen temperature;
measuring the platen temperature by a contact temperature measurement;
sending a first transfer signal to transfer a substrate to the substrate platen in the process chamber, when the substrate platen is at the platen temperature;
after a temperature-stabilization interval, at a transfer instance, sending a second transfer signal to perform a transfer of the substrate from the process chamber and place the substrate in a substrate position in a preheat station;
recording a zero time, the zero time corresponding to when the transfer of the substrate commences;
receiving a plurality of voltage readings as a function of time from an optical pyrometer after the zero time, the optical pyrometer measuring the substrate when the substrate is placed in the substrate position;
generating a voltage decay curve comprising the plurality of voltage readings, over a measurement interval; and
extrapolating the voltage decay curve from the measurement interval to the zero time.

10. The method of claim 9 , the generating the voltage decay curve comprising fitting a polynomial function to the plurality of voltage readings, the method further comprising:
determining a zero-time pyrometer voltage data, corresponding to the process temperature, by determining a pyrometer voltage corresponding to an intersection of the voltage decay curve at zero time with a horizontal line.

11. The method of claim 10 , wherein the sending the heat signal to heat the substrate platen, the measuring the platen temperature, the sending the first transfer signal, the sending the second transfer signal, and the determining the zero-time pyrometer voltage data comprise a first calibration cycle, the method further comprising:
performing at least one additional calibration cycle, wherein the first temperature is increased between the first calibration cycle and the at least one additional calibration cycle.

12. The method of claim 11 , wherein in each calibration cycle of the at least one additional calibration cycle, an additional zero-time pyrometer voltage data is generated, the method further comprising generating a calibration curve comprising a plurality of voltage-platen temperature data points, based upon the first calibration cycle and at least one additional calibration cycle.

13. The method of claim 12 , further comprising:
recording a first substrate type for the substrate;
loading a process substrate into the preheat station;
determining the process substrate corresponds to the first substrate type;
heating the process substrate in the preheat station to a targeted temperature, using an experimental substrate temperature of the substrate recorded by an optical pyrometer, wherein the experimental temperature is determined by:
outputting an experimental voltage, generated in the optical pyrometer by emission from the process substrate; and
mapping the experimental voltage to a corresponding substrate temperature on the calibration curve.

14. The method of claim 12 , further comprising:
determining, for a targeted temperature range, an offset between platen temperature and substrate temperature, when the substrate is disposed on the substrate platen; and
generating a corrected calibration curve based upon the calibration curve and the offset.

15. The method of claim 9 , further comprising, before the sending

Assignees

• Applied Materials Inc

Inventors

• Wilson Eric D
• Anella Steven
• Lischer D Jeffrey
• Mclane James
• Pomerleau Bradley M
• Sun Dawei

Classifications

• H10P72/7604

  the wafers being placed on a susceptor, stage or support · CPC title

• H10P72/0436

  mainly by radiation · CPC title

• H10P72/0431

  Apparatus for thermal treatment · CPC title

• H10P72/0602 Primary

  Temperature monitoring · CPC title

• G01K7/02

  using thermoelectric elements, e.g. thermocouples · CPC title