Patent ID: 9475150
Filing Date: 2016-10-25
CPC Classification: B23K,B65B,B65D

Claim Text:
1. A laser annealing system for annealing dies supported by a wafer having melt temperature and a surface that supports dies each having a variation in emissivity, comprising: a chuck that supports the wafer, and a movable stage that supports the chuck and that is adapted to move the chuck and wafer; a laser that generates an initial laser beam and that has an adjustable output power and an amount of 1/f noise that can cause variations in an annealing temperature, wherein the annealing temperature is less than the wafer melt temperature; an optical system configured to receive the initial laser beam and form therefrom an annealing laser beam and to direct a portion of the annealing laser beam to a photodetector system that in response generates a detector signal, the optical system being arranged so that the annealing laser beam is made incident upon and scans over the wafer surface due to the movement of the wafer, and heats the wafer to the annealing temperature; a thermal emission detector system arranged relative to the wafer surface and configured to receive thermal emission radiation therefrom that is generated by the annealing laser beam and average the received thermal emission radiation over an area of one or more of the dies, and in response generates a thermal emission signal; a first control loop configured to receive the detector signal and control the laser to adjust the output power at a first frequency f a second control loop configured to receive the thermal emission signal and control the laser to adjust the output power at a second frequency f