US Patent 7849916 Temperature control apparatus and method

An apparatus for use with a process liquid for controlling the temperature of a semiconductor-processing target comprises first and second tanks adapted for holding process liquid, at least one fluid level sensor carried by the first tank for monitoring the amount of process liquid in the first tank, and a valve coupled to one of the at least one fluid level sensor and configured to increases the flow of process liquid from the second tank to the target when the amount of process liquid in the first tank drops to a first predetermined amount. The first tank may include first and second compartments partially separated by a divider with a top whereby process liquid in the first compartment flows over the top of the divider into the second compartment.