Etalon thermometer for plasma environments

Abstract

The present invention provides a method and apparatus for determining the temperature of a substrate in a processing chamber. [Solution] The method and apparatus described herein utilize an etalon assembly and heterodyne effect to determine a first temperature of a substrate. The first temperature of the substrate is determined without physical contact with the substrate. A separate temperature sensor also measures a second temperature of the substrate and / or substrate support at a similar location. The first and second temperatures are used to calibrate one of the models of processes performed in a processing chamber, or to adjust the process parameters of a process performed in a processing chamber, using a temperature sensor placed within the substrate support.

Claims

1. A method for detecting a temperature suitable for use in a semiconductor processing chamber, wherein the method is To pass the first ray through the first etalon, To provide a second etalon, the first light ray is passed through a substrate placed in the processing chamber, Generating a reflected second beam and a transmitted second beam from the first ray, wherein the reflected second beam is passed through both the first etalon and the second etalon, and the generation of the reflected second beam and the transmitted second beam is performed after that. Determining the fringe spacing from the interference fringes of either the reflected second beam or the transmitted second beam, The temperature of the substrate is determined based on the fringe spacing. Methods that include...

2. The method according to claim 1, wherein the fringe spacing correlates with an empirically derived thermo-optic coefficient value of either the first etalon or the second etalon.

3. The method according to claim 1, further comprising directing the first ray through the first etalon and the substrate disposed within the processing chamber, to direct the first ray toward the surface of the substrate facing away from the lid of the processing chamber and toward the lid.

4. The method according to claim 1, further comprising directing the first ray through the first etalon and the substrate disposed in the processing chamber, to direct the first ray to the surface of the substrate facing the lid of the processing chamber and in the opposite direction to the lid.

5. Furthermore, Calibrating the substrate temperature sensor of the processing chamber using the temperature determined using the fringe spacing of the interference fringes. The method according to claim 1, including the method described in claim 1.

6. The method according to claim 1, further comprising directing the first ray from the first etalon to the substrate, while a plasma process is performed on the substrate located in the processing chamber, the first ray is directed through the plasma.

7. The method according to claim 1, wherein, prior to determining the fringe spacing, the processing chamber and the substrate are brought to a steady state temperature, the thickness of the substrate is calculated using an initial substrate temperature measurement, and the first thickness of the first etalon is adjusted to be within 10 μm of the second thickness of the substrate by removing the first etalon from the path of the first ray and placing a replacement first etalon in the path of the first ray.

8. Placing the alternative first etalon within the path of the first ray is further, Based on the thickness of the substrate, the first ray and at least one of the multiple reference etalons are automatically moved and aligned. The method according to claim 7, including the method described in claim 7.

9. Furthermore, To direct at least the first ray and the third ray to different locations on the substrate placed in the processing chamber. The method according to claim 1, including the method described in claim 1.

10. To direct the first ray and the third ray, Directing the first ray towards the central region of the substrate, and directing the third ray towards the edge region of the substrate. The method according to claim 9, including the method described in claim 9.

11. To provide direction, further, Directing at least one ray of light to each region of the substrate related to the temperature control zone of the substrate support that supports the substrate within the processing chamber. The method according to claim 9, including the method described in claim 9.

12. Furthermore, Using the aforementioned temperature, the temperature sensor in the processing chamber is calibrated. Applying a temperature offset to one or more measurements of the temperature sensor, Adjusting the model of the process executed in the processing chamber, and Adjusting the process parameters of the process executed within the processing chamber. The method according to claim 1, comprising one or more of the following.

13. A method for detecting a temperature suitable for use in a semiconductor processing chamber, wherein the method is To pass the first ray through the first etalon, The method of passing the first ray through a substrate placed in the processing chamber to provide a second etalon, wherein the first etalon and the second etalon form an etalon assembly, and either the first etalon or the second etalon generates a reflected second beam and a transmitted second beam from the first ray. Determining the fringe spacing from interference fringes generated within either the reflected second beam or the transmitted second beam of the etalon assembly, Determining the temperature of the substrate based on the fringe spacing, The method involves providing the temperature to the controller of the processing chamber, Using the aforementioned temperature, the temperature sensor in the processing chamber is calibrated. Applying a temperature offset to one or more measurements of the temperature sensor, Adjusting the model of the process executed in the processing chamber, and Adjusting the process parameters of the process executed within the processing chamber. The following is performed before executing one or more of the following: providing the temperature to the controller of the processing chamber Methods that include...

14. Furthermore, To direct at least the first ray and the third ray to different locations on the substrate placed in the processing chamber. The method according to claim 13, including the method described in claim 13.

15. The method according to claim 13, wherein directing the first ray from the first etalon to the substrate further includes directing the first ray through plasma while a plasma process is performed on the substrate located in the processing chamber.

16. The method according to claim 13, wherein, prior to determining the temperature, the processing chamber and the substrate are brought to a steady state temperature, the thickness of the substrate is calculated using an initial substrate temperature measurement, and the first thickness of the first etalon is adjusted to be within 10 μm of the second thickness of the substrate by removing the first etalon from the path of the first ray and placing a replacement first etalon in the path of the first ray.

17. A method for calibrating temperature measurement inside a processing chamber, The process steps are performed on a reference substrate within the processing chamber, The process steps described above are performed while measuring the first temperature of the substrate placed in the processing chamber using the first etalon assembly, Passing the first light ray through the first etalon and the substrate, The substrate providing the second etalon is crossed with the first ray, Using either the first etalon or the second etalon, the first ray is split into a reflected second beam and a transmitted second beam. Using a radiation measuring device to collect either the reflected second beam or the transmitted second beam, and To determine the first temperature of the substrate, the reflected second beam or the transmitted second beam is analyzed. This includes measuring the first temperature of the substrate, Using the first temperature sensor, the second temperature of either the substrate or the substrate support on which the substrate is placed is measured. The first temperature and the second temperature are transmitted to the controller, Using the first temperature and the second temperature, the model in the controller is calibrated. Methods that include...

18. The method according to claim 17, wherein the process step is a plasma etching process.

19. The method according to claim 17, wherein the refractive index of the substrate is about 2 to about 6.

20. The method according to claim 17, further comprising measuring the first temperature and the second temperature along a first annular portion of the substrate, and further measuring a third temperature in a second annular portion of the substrate using a second etalon assembly.

Images