Abstract: A method and apparatus for measuring and controlling the temperature of a semiconductor device is described. The temperature of a semiconductor device is controlled by measuring the temperature at the semiconductor device and adjusting the temperature by supplying a coolant to the semiconductor device over a coolant line. The amount of coolant which flows to the semiconductor device is controlled by a solenoid switch connected to a valve in the coolant line. A system for measuring and controlling the temperatures of multiple semiconductor devices is also described.