Patent ID: 8691598
Filing Date: 2014-04-08
Classification: B23K,C30B,H01L

Abstract:
1. A method of annealing with a laser a wafer having a melt temperature and a surface that supports an array of dies with each die having a varying emissivity, comprising: scanning an annealing laser beam from the laser over the array of dies, wherein the laser has laser noise and is adjustable to control an amount of power in the annealing laser beam, wherein the annealing laser beam creates an annealing temperature at the wafer surface that does not exceed the wafer melt temperature; measuring and controlling the amount of power in the annealing laser beam using a first control loop that measures the amount of power and operates at a first frequency f controlling the amount of power in the annealing laser beam using a second control loop that operates at a second frequency f