Abstract: An induction heating systems using a plurality of zones in a coil provides selective heating control for better uniformity especially for semiconductor and other thin film processing applications. By arranging the zones to have different resonance frequencies, the power supply may control the various zones by altering its frequency output. The power supply may also act to control the differential heating by switching among zones in conjunction with the frequency control, by sweeping through a variety of frequencies, by simultaneously providing power over different frequencies, by altering the residence time at each frequency, or by outputting different powers to each frequency or the like. Each zone may thus be tuned as appropriate to achieve the desired induction heating characteristic.