Patent ID: 8791392

Claim:
A method of fault detection for a multi-zone heating plate in a substrate support assembly having a cooling plate below the heating plate during processing of a semiconductor substrate in a chamber of a semiconductor processing apparatus, the heating plate comprising a plurality of planar heater zones, a plurality of power supply lines and a plurality of power return lines, wherein each of the power supply lines is connected to a plurality of the planar heater zones and each of the power return lines is connected to a plurality of the planar heater zones, and no two planar heater zones share the same pair of power supply line and power return line; the method comprising: (a) loading the semiconductor substrate onto the substrate support; (b) supplying process gas to the chamber; (c) energizing the process gas into a plasma; (d) supplying power to one or more of the power supply lines to achieve a support temperature profile while circulating coolant in the cooling plate; wherein the support temperature profile is created by controlling a first multiplexor connected to the power supply lines and a second multiplexor connected to the power return lines to independently control each planar heater zone with the supplied power; (e) obtaining a measured total heating power of all of the planar heater zones; (f) comparing the measured total heating power to a pre-established total heating power of the planer heater zones; (g) if the measured total heating power deviates from the pre-established total heating power by a pre-determined margin, triggering an alarm signal.