Pyrometry filter for thermal process chamber
Embodiments of the invention generally relate to pyrometry during thermal processing of semiconductor substrates. More specifically, embodiments of the invention relate to a pyrometry filter for a thermal process chamber. In certain embodiments, the pyrometry filter selectively filters selected wavelengths of energy to improve a pyrometer measurement. The pyrometry filter may have various geometries which may affect the functionality of the pyrometry filter.
1. An apparatus for use in a thermal processing chamber comprising:
a window having a plurality of surfaces including a top surface and a bottom surface, the window having a geometric shape wherein a thickness of the window at a center region is less than a thickness of the window at a peripheral region and wherein the top surface and bottom surface taper inwardly from the peripheral region to the center region;
a reflective coating disposed on the top surface and the bottom surface;
an index matching material disposed on the reflective coating adjacent at least one of the top surface and the bottom surface; and
an absorptive coating disposed on the peripheral region.
2. The apparatus of claim 1 , wherein the window comprises quartz.
3. The apparatus of claim 1 , wherein the index matching material is selected in relationship to a refractive index of the window.
4. The apparatus of claim 3 , wherein the reflective coating is selected to reflect a predetermined range of wavelengths between about 700 nm to about 1000 nm.
5. The apparatus of claim 1 , wherein the reflective coating comprises a dielectric material.
6. The apparatus of claim 5 , wherein the dielectric material comprises multiple layers.
7. The apparatus of claim 1 , wherein the window is symmetric around a vertical axis.
8. The apparatus of claim 7 , wherein the window is symmetric around a horizontal axis.
9. The apparatus of claim 1 , wherein the plurality of surfaces are linear.
10. The apparatus of claim 1 , wherein at least two of the plurality of surfaces are non-linear.
11. A system for processing a substrate, comprising:
a radiation source;
a pyrometer; and
a window disposed between the radiation source and the pyrometer, the window further comprising:
a peripheral region and a plurality of surfaces including a top surface and a bottom surface, the window having a geometric shape wherein a thickness of the window at a center region is less than a thickness of the window at the peripheral region and wherein the top surface and the bottom surface taper inwardly from the peripheral region to the center region;
a reflective coating disposed on the top surface and the bottom surface;
an index matching material disposed on the reflective coating adjacent at least one of the top surface and the bottom surface; and
an absorptive coating disposed on the peripheral region.
12. The system of claim 11 , wherein the pyrometer detects wavelengths between about 700 nm to about 1000 nm.
13. The system of claim 11 , wherein the window comprises quartz.
14. The system of claim 11 , wherein the index matching material is selected in relationship to a refractive index of the window.
15. The apparatus of claim 14 , wherein the reflective coating is selected to reflect a predetermined range of wavelengths between about 700 nm to about 1000 nm.
16. The apparatus of claim 11 , wherein the reflective coating comprises a dielectric material.
17. The apparatus of claim 11 , wherein the window is symmetric around a vertical axis.
18. The apparatus of claim 17 , wherein the window is symmetric around a horizontal axis.
19. The apparatus of claim 11 , wherein the plurality of surfaces are linear.
20. The apparatus of claim 11 , wherein at least two of the plurality of surfaces are non-linear.