Patent ID: 6960254

Claim:
A method for use with a crystal growing apparatus for optimizing a cooling rate of a monocrystalline ingot grown according to a Czochralski process, said crystal growing apparatus having a heated crucible containing a semiconductor melt from which the ingot is grown, said ingot being grown on a seed crystal pulled from the melt, said crystal growing apparatus further having a receiving chamber into which the ingot is pulled, said ingot being pulled along a generally longitudinal path toward the receiving chamber, said method comprising: determining a first temperature of the ingot when the ingot is at a first position along the path; determining a second temperature of the ingot when the ingot is at a second position along the path, said first and second positions being separated by a distance D along the path; determining a cooling rate of the ingot as a function of a difference between the first temperature and the second temperature relative to an amount of time for pulling the ingot the distance D; generating a signal representative of an error between a target cooling rate of the ingot and the determined cooling rate of the ingot; and adjusting one or more post-growth processing parameters as a function of the error signal thereby to control the cooling rate of the ingot.