Method and apparatus for thermally treating substrates
View Patent ↗The object of the disclosure is to measure temperature using pyrometers, in a simple and economic way, enabling precise temperature measurement, even for low temperatures. The disclosure presents an apparatus and method for thermally treating substrates, wherein the substrate is exposed to at least a first and at least a second radiation; the predetermined wavelengths of the first radiation are absorbed between the first radiation source and the substrate; a radiation from the substrate is measured in the predetermined wavelength using a radiation detector arranged on the same side as a second radiation source; the second radiation from the second radiation source is modulated and determined.
1. A method for thermally treating substrates, including the steps of:
irradiating a substrate with at least one first radiation for heating said substrate, wherein said first radiation is emitted from at least one first radiation source;
absorbing prescribed wavelengths of said first radiation between said first radiation source and said substrate;
irradiating said substrate with at least one second radiation for heating said substrate, wherein said second radiation is emitted from at least one second radiation source and includes radiation that lies in said prescribed wavelengths and strikes said substrate;
measuring a radiation coming from said substrate at said prescribed wavelengths with a radiation detector that is disposed on the same side as is said second radiation source;
modulating said second radiation that is emitted by said second radiation source; and
determining said second radiation being emitted from said at least one second radiation source due to the measurement.
2. A method according to claim 1 , wherein said first and said second radiation are directed toward said substrate from opposite sides.
3. A method according to claim 1 , which includes regulating said first radiation source.
4. A method according to claim 1 , which includes generating the first and second radiation with heating lamps.
5. A method according to claim 4 , which includes absorbing the prescribed wavelengths of said first radiation by bulbs of first ones of said heating lamps.
6. A method according to claim 1 , which includes absorbing said prescribed wavelengths of said first radiation by a process chamber wall that is disposed between said first radiation source and said substrate.
7. A method according to claim 1 , wherein wavelengths of said first radiation between 2.7 and 2.8 μm are absorbed.
8. A method according to claim 1 , which includes cooling an element that absorbs said prescribed wavelengths.
9. A method according to claim 8 , which includes cooling said element with a cooling gas or a cooling liquid.
10. A method according to claim 1 , wherein said radiation coming from said substrate is measured with a pyrometer.
11. A method according to claim 1 , wherein radiation coming from said substrate is measured with a further radiation detector.
12. A method according to claim 11 , wherein said further radiation detector measures radiation beyond said prescribed wavelengths.
13. A method according to claim 12 , wherein said further radiation detector measures radiation below and above said prescribed wavelengths.
14. A method according to claim 11 , wherein said further radiation detector is directed toward that side of said substrate that is remote from said second radiation source and measures radiation having the prescribed wavelength.
15. A method according to claim 1 , wherein radiation originating from said first radiation source contributes less than 50%, and preferably less than 25%, to the heating of said substrate at low temperatures.