Pulse train annealing method and apparatus
The present invention generally describes apparatuses and methods used to perform an annealing process on desired regions of a substrate. In one embodiment, pulses of electromagnetic energy are delivered to a substrate using a flash lamp or laser apparatus. The pulses may be from about 1 nsec to about 10 msec long, and each pulse has less energy than that required to melt the substrate material. The interval between pulses is generally long enough to allow the energy imparted by each pulse to dissipate completely. Thus, each pulse completes a micro-anneal cycle. The pulses may be delivered to the entire substrate at once, or to portions of the substrate at a time. Further embodiments provide an apparatus for powering a radiation assembly, and apparatuses for detecting the effect of pulses on a substrate.
1. An apparatus for treating a substrate, comprising:
a body portion;
a substrate support coupled to the body portion;
a source of electromagnetic radiation disposed in a radiation assembly, the radiation assembly coupled to the body portion;
one or more power supplies coupled to the radiation assembly; and
a controller coupled to the power supply, the radiation assembly, or both to direct at least 100 pulses of electromagnetic energy toward the substrate support, each pulse having energy density of at least 0.2 J/cm 2 , wherein the controller is configured to operate an optical switch disposed between the source of electromagnetic radiation and the body portion.
2. The apparatus of claim 1 , further comprising a gas delivery system configured to deliver one or more gases to the radiation assembly and body portion.
3. The apparatus of claim 1 , wherein the source of electromagnetic radiation comprises one or more lasers.
4. The apparatus of claim 3 , wherein the optical switch is configured to change state in less than 1 nsec.
5. The apparatus of claim 1 , wherein the controller is configured to generate pulses of power from the power supply to the source of electromagnetic radiation.
6. The apparatus of claim 1 , wherein the substrate support comprises a heating element.
7. The apparatus of claim 1 , wherein the optical switch is capable of changing state in less than 1 nsec.
8. A method of annealing a substrate, comprising:
disposing the substrate on a substrate support;
generating pulses of electromagnetic energy by interrupting a continuous beam of electromagnetic radiation using an optical switch; and
directing at least 100 of the pulses of electromagnetic energy toward the substrate, each pulse having energy density at least 0.2 J/cm 2 .
9. The method of claim 8 , wherein each pulse has energy less than that required to melt a portion of the substrate.
10. The method of claim 9 , further comprising pre-heating the substrate.
11. The method of claim 8 , wherein each pulse is between about 1 nsec and 10 msec in duration.
12. The method of claim 11 , wherein the pulses of electromagnetic energy are generated from one or more lasers.
13. The method of claim 12 , wherein each pulse is directed at a portion of the substrate.
14. The method of claim 8 , wherein each pulse has the same energy and duration.
15. The method of claim 8 , wherein the substrate comprises a plurality of portions, and at least 100 pulses of electromagnetic energy are delivered to each portion, each pulse having energy density at least 0.2 J/cm 2 .
16. The method of claim 8 , wherein each pulse partially anneals the substrate.