Integrated substrate temperature measurement on high temperature ceramic heater
Embodiments described herein include integrated systems used to directly monitor a substrate temperature during a plasma enhanced deposition process and methods related thereto. In one embodiment, a substrate support assembly includes a support shaft, a substrate support disposed on the support shaft, and a substrate temperature monitoring system for measuring a temperature of a substrate to be disposed on the substrate support. The substrate temperature monitoring system includes a optical fiber tube, a light guide coupled to the optical fiber tube, and a cooling assembly disposed about a junction of the optical fiber tube and the light guide. Herein, at least a portion of the light guide is disposed in an opening extending through the support shaft and into the substrate support and the cooling assembly maintains the optical fiber tube at a temperature of less than about 100° C. during substrate processing.
1. A substrate support assembly, comprising:
a support shaft;
a substrate support disposed on the support shaft; and
a substrate temperature monitoring system for measuring a temperature of a substrate to be disposed on the substrate support, comprising:
an optical fiber tube;
a light guide coupled to the optical fiber tube, wherein the light guide comprises a sapphire tube having a length of at least about 400 mm and an inner diameter of at least 40 mm, and at least a portion of the light guide is disposed in an opening extending through the support shaft and into the substrate support; and
a cooling assembly disposed about a junction of the optical fiber tube and the light guide, wherein the cooling assembly maintains the optical fiber tube at a temperature of less than about 100° C. during substrate processing.
2. The substrate support assembly of claim 1 , wherein the substrate temperature monitoring system further comprises:
a sheath disposed in the opening to protect the light guide from breakage by restricting lateral movement thereof.
3. The substrate support assembly of claim 2 , wherein the sheath comprises the same material as the support shaft.
4. The substrate support assembly of claim 1 , wherein an end of the light guide is within 1 mm of a substrate when a substrate is disposed on the substrate support.
5. The substrate support assembly of claim 1 , wherein the junction of the optical fiber tube and the light guide is isolated from the opening by a vacuum seal.
6. The substrate support assembly of claim 1 , wherein the substrate support further comprises a window positioned flush with or below a substrate receiving surface of the substrate support.
7. The substrate support assembly of claim 6 , wherein the light guide extends to within 0.5 mm of the window.
8. A processing chamber, comprising:
a chamber body defining a processing volume; and
a substrate support assembly disposed in the processing volume, the substrate support assembly comprising:
a support shaft;
a substrate support disposed on the support shaft;
a substrate temperature monitoring system for measuring a temperature of a substrate to be disposed on the substrate support, comprising:
an optical fiber tube;
a light guide coupled to the optical fiber tube, wherein the light guide comprises a sapphire tube having a length of at least 400 mm and an inner diameter of at least about 40 mm, and at least a portion of the light guide is disposed in an opening extending through the support shaft and into the substrate support; and
a cooling assembly disposed about a junction of the optical fiber tube and the light guide, wherein the cooling assembly maintains the optical fiber tube at a temperature of less than about 100° C. during substrate processing.
9. The processing chamber of claim 8 , wherein the substrate temperature monitoring system further comprises:
a sheath disposed in the opening to protect the light guide from breakage by restricting lateral movement thereof.
10. The processing chamber of claim 8 , wherein an end of the light guide is within 1 mm of a substrate when a substrate is disposed on the substrate support.
11. The processing chamber of claim 8 , wherein the junction of the optical fiber tube and the light guide is isolated from the opening by a vacuum seal.
12. The processing chamber of claim 8 , wherein the substrate support further comprises a window positioned flush with or below a substrate receiving surface of the substrate support.
13. The processing chamber of claim 8 , further comprising a computer readable medium having instructions stored thereon for a method of processing a substrate, the method comprising:
positioning the substrate on a substrate receiving surface of the substrate support;
flowing one or more processing gases into the processing volume;
forming a plasma of the one or more processing gases;
heating the substrate to a temperature of 500° C. or greater;
measuring a temperature of the substrate using the optical fiber tube when the temperature of the substrate reaches or exceeds 500° C.; and
depositing a material layer on the substrate.
14. The processing chamber of claim 13 , wherein the method of processing the substrate further comprises maintaining the optical fiber tube at a temperature less than about 100° C.