Temperature measurement and heat-treating methods and systems
View Patent ↗Temperature measurement and heat-treating methods and systems. One method includes identifying a temperature of a first surface of a workpiece, and controlling energy of an irradiance flash incident on the first surface of the workpiece, in response to the temperature of the first surface. Identifying may include identifying the temperature of the first surface during an initial portion of the irradiance flash, and controlling may include controlling the power of a remaining portion of the irradiance flash. The first surface of the workpiece may include a device side of a semiconductor wafer.
1. A method of heat-treating a workpiece, the method comprising:
a) identifying a temperature of a first surface of a workpiece; and
b) controlling energy of an irradiance flash incident on the first surface of the workpiece, in response to the temperature of the first surface;
wherein identifying comprises identifying the temperature of the first surface during an initial portion of the irradiance flash, and wherein controlling comprises controlling the lower of a remaining portion of the irradiance flash.
2. The method of claim 1 further comprising producing the irradiance flash, wherein the irradiance flash has a duration less than a thermal conduction time of the workpiece.
3. The method of claim 1 wherein identifying comprises repeatedly identifying successive values of the temperature of the first surface while the first surface is being exposed to the irradiance flash, the irradiance flash having a duration less than a thermal conduction time of the workpiece.
4. The method of claim 1 wherein the first surface of the workpiece comprises a patterned surface and wherein identifying comprises identifying the temperature of the patterned surface during the initial portion of the irradiance flash.
5. The method of claim 1 wherein the first surface of the workpiece comprises a device side of a semiconductor wafer and wherein identifying comprises identifying the temperature of the device side during the initial portion of the irradiance flash.
6. The method of claim 1 wherein controlling comprises reducing an energy output of the irradiance flash.
7. The method of claim 6 wherein reducing comprises causing at least a portion of an electrical pulse to bypass at least one irradiance device that produces the irradiance flash from the pulse.
8. The method of claim 1 wherein controlling comprises increasing a peak power output of the irradiance flash.
9. The method of claim 8 wherein increasing comprises causing at least a portion of an electrical pulse to bypass an inductor in electrical communication with at least one irradiance device that produces the irradiance flash from the pulse.
10. The method of claim 1 wherein controlling comprises redirecting at least a portion of an electrical pulse from which the irradiance flash is produced.
11. The method of claim 10 further comprising initiating the irradiance flash by closing a first switch to commence discharge of the electrical pulse through an irradiance device, and wherein redirecting comprises closing a second switch to redirect the at least a portion of the electrical pulse.
12. The method of claim 10 wherein redirecting comprises closing a switch connected across an irradiance device to cause the at least a portion of the electrical pulse to flow through the switch instead of the irradiance device.
13. The method of claim 12 wherein the switch is connected in series with a resistor, wherein the switch and the resistor are connected across the irradiance device, and wherein redirecting comprises closing the switch to cause the at least a portion of the electrical pulse to flow through the switch and the resistor instead of the irradiance device.
14. The method of claim 10 wherein an initial portion of the electrical pulse travels along a primary path to produce the initial portion of the flash, and wherein redirecting the at least a portion of the electrical pulse comprises redirecting at least part of a remaining portion of the electrical pulse along a secondary path having a lower inductance than the primary path.
15. An apparatus for heat-treating a workpiece, the apparatus comprising:
a) a temperature measurement system configured to identify a temperature of a first surface of the workpiece; and
b) an irradiance control system configured to control energy of an irradiance flash incident on the first surface of the workpiece, in response to the temperature of the first surface;
wherein the irradiance control system comprises an irradiance system operable to expose the first surface of the workpiece to the irradiance flash, and a processor circuit configured to control the irradiance system to control the energy of the irradiance flash; and
wherein the temperature measurement system is configured to identify the temperature of the first surface during an initial portion of the irradiance flash, and wherein the irradiance control system is configured to control the power of a remaining portion of the irradiance flash.
16. The apparatus of claim 15 wherein the irradiance system is operable to produce the irradiance flash to have a duration less than a thermal conduction time of the workpiece.
17. The apparatus of claim 15 wherein the temperature measurement system is configured to repeatedly identify successive values of the temperature of the first surface while the first surface is being exposed to the irradiance flash, the irradiance flash having a duration less than a thermal conduction time of the workpiece.
18. The apparatus of claim 15 wherein the processor circuit is configured to control the irradiance system to reduce an energy output of the irradiance flash.
19. The apparatus of claim 18 wherein the processor circuit is configured to cause at least a portion of an electrical pulse to bypass at least one irradiance device that produces the irradiance flash from the pulse.
20. The apparatus of claim 15 wherein the processor circuit is configured to control the irradiance system to increase a peak power output of the irradiance flash.
21. The apparatus of claim 20 wherein the processor circuit is configured to cause at least a portion of an electrical pulse to bypass an inductor in electrical communication with at least one irradiance device that produces the irradiance flash from the pulse.
22. The apparatus of claim 15 wherein the irradiance control system comprises a redirector in communication with an electrical pulse generator and with at least one irradiance device of the irradiance system, and wherein the processor circuit is configured to control the redirector to redirect at least a portion of an electrical pulse from which the irradiance flash is produced.
23. The apparatus of claim 22 wherein the irradiance control system comprises a first switch, wherein the redirector comprises a second switch, wherein the processor circuit is configured to close the first switch to commence discharge of the electrical pulse through the at least one irradiance device, and wherein the processor circuit is configured to close the second switch to redirect the at least a portion of the electrical pulse.
24. The apparatus of claim 22 wherein the redirector comprises a solid state switch.
25. The apparatus of claim 24 wherein the solid state switch comprises a silicon controlled rectifier (SCR).
26. The apparatus of claim 22 wherein the redirector comprises a switch connected across the at least one irradiance device, and wherein the processor circuit is configured to close the switch to cause the at least a portion of the electrical pulse to flow through the resistor instead of the at least one irradiance device.
27. The apparatus of claim 22 wherein the redirector comprises a switch and a resistor in series, wherein the switch and the resistor are connected across the at least one irradiance device, and wherein the processor circuit is configured to close the switch to cause the at least a portion of the electrical pulse to flow through the switch and the resistor instead of the at least one irradiance device.
28. The apparatus of claim 22 wherein the electrical pulse generator and the at least one irradiance device are in electrical communication via a primary path to produce the initial portion of the flash, and wherein the processor circuit is configured to control the redirector to place the electrical pulse generator and the at least one irradiance device in electrical communication via a secondary path having a lower inductance than the primary path.
29. An apparatus for heat-treating a workpiece, the apparatus comprising:
a) means for identifying a temperature of a first surface of a workpiece; and
b) means for controlling energy of an irradiance flash incident on the first surface of the workpiece, in response to the temperature of the first surfaces;
wherein the means for identifying comprises means for identifying the temperature of the first surface during an initial portion of the irradiance flash, and wherein the means for controlling comprises means for controlling the power of a remaining portion of the irradiance flash.