Temperature controlled substrate holder with non-uniform insulation layer for a substrate processing system

A substrate holder for supporting a substrate in a processing system, comprising:

• a temperature controlled support base having a first temperature;
• a substrate support opposing said temperature controlled support base and configured to support the substrate;
• one or more heating elements coupled to said substrate support, and configured to heat the substrate support to a second temperature above said first temperature;
• and
• a thermal insulator disposed between said temperature controlled support base and said substrate support,
• wherein said thermal insulator comprises a material, which has a non-uniform spatial variation of thermal conductivity between the material from a substantially central region to a substantially edge region of said thermal insulator, or a non-uniform spatial variation of a thickness between the material from a substantially central region to a substantially edge region of said thermal insulator, or a non-uniform spatial variation of both the thermal conductivity and the thickness,
• wherein the thermal insulator has at least a first non-zero thickness thinner than a second non-zero thickness, the first non-zero thickness aligning with a protrusion on the support base so as to interlock the thermal insulator and the support base, and
• the heat transfer coefficient of the thermal insulator non-uniformly varies across said thermal insulator in accordance with said first non-zero thickness and said second non-zero thickness.