Method and apparatus for detecting a polishing endpoint based upon heat conducted through a semiconductor wafer

A method of polishing a first layer of a semiconductor wafer down to a second layer of the semiconductor wafer is disclosed. One step of the method includes heating a back surface of the semiconductor wafer to a first temperature level so as to cause a front surface of the semiconductor wafer to have a second temperature level. Another step of the method includes polishing the semiconductor wafer whereby material of the first layer is removed from the semiconductor wafer. The polishing step causes the second temperature level of the front surface to change at a first rate as the material of the first layer is being removed. The method also includes the step of halting the polishing step in response to the second temperature level of the front surface changing at a second rate that is indicative of the second layer being polished during the polishing step. Polishing systems are also disclosed which detect a polishing endpoint for a semiconductor wafer based upon heat conducted through the semiconductor wafer.