| CPC C30B 25/165 (2013.01) [C30B 25/10 (2013.01)] | 20 Claims |
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1. An apparatus comprising:
a susceptor in an epitaxial growth chamber, the susceptor configured to be able to rotate, the susceptor comprising a non-transparent material;
a plurality of lower pyrometers configured to monitor thermal radiation from corresponding ones of a first plurality of points on a backside of a wafer on the rotating susceptor, wherein the number of lower pyrometers of the plurality of lower pyrometers is equal to the number of points of the first plurality of points, wherein a width of a gap that is disposed between the backside of the wafer and a top surface of the rotating susceptor decreases continuously in a direction from a center of the wafer to an edge of the wafer, wherein a thickness of the susceptor decreases continuously in a direction from a center of the susceptor to an edge of the susceptor, wherein a center portion of the susceptor has a thickness that is greater than thicknesses of other portions of the susceptor, wherein the plurality of lower pyrometers comprise:
a first pyrometer configured to monitor thermal radiation from a first point of the first plurality of points on the backside of the wafer on the rotating susceptor, the first pyrometer also being configured to monitor the thermal radiation from the first point while being disposed under and being overlapped by the susceptor and the wafer; and
a second pyrometer configured to monitor thermal radiation from a second point of the first plurality of points on the backside of the wafer on the rotating susceptor, the second pyrometer also being configured to monitor the thermal radiation from the second point while being disposed under and being overlapped by the susceptor and the wafer;
a first heating source in a first region of the epitaxial growth chamber and a second heating source in a second region of the epitaxial growth chamber, wherein a first controller is configured to adjust an output of the first heating source based upon the monitored thermal radiation from the first point, and an output of the second heating source based upon the monitored thermal radiation from the second point, wherein a center portion of the first heating source is disposed at a level that is between a topmost surface of the first pyrometer and a bottommost surface of the first pyrometer, and between a topmost surface of the second pyrometer and a bottommost surface of the second pyrometer, and wherein the first heating source extends laterally between a first sidewall of the first pyrometer and a second sidewall of the second pyrometer;
a third pyrometer configured to monitor thermal radiation from a third point on a frontside of the wafer;
a fourth pyrometer configured to monitor thermal radiation from a fourth point on the frontside of the wafer, wherein a second controller is configured to adjust a flow rate of one or more precursors injected into the epitaxial growth chamber based upon the monitored thermal radiation from the first, second, third, and fourth points; and
a processing unit configured to assume that a first temperature of the first point and a second temperature of the third point are the same and estimate a first real-time thickness of an epitaxial film growing at the third point on the frontside of the wafer, and wherein the processing unit is also configured to combine values of the monitored thermal radiation from the second point and values of the monitored thermal radiation from the fourth point and estimate a second real-time thickness of the epitaxial film growing at the fourth point on the frontside of the wafer.
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