Electrostatic chuck and semiconductor manufacturing apparatus

An electrostatic chuck comprising:

• a ceramic dielectric substrate having a first major surface configured to have a process object mounted thereon and a second major surface on a side opposite to the first major surface;
• a base plate supporting the ceramic dielectric substrate;
• and
• a heater unit which heats the ceramic dielectric substrate, wherein
• the heater unit includes a first heater element and a second heater element,
• the second heater element having a plurality of main zones separated from each other in a radial direction,
• the first heater element having a plurality of sub-zones separated from each other,
• a number of the sub-zones being larger than a number of the main zones,
• the main zones including a first main zone and a second main zone adjacent to the first main zone with a first boundary therebetween in the radial direction,
• the sub-zones including a first sub-zone having a first radial end as an end portion thereof in the radial direction, the first sub-zone overlapping at least one of the first main zone and the second main zone in a Z-direction perpendicular to the first major surface, and
• at least a portion of the first radial end of the first sub-zone not overlapping the first boundary in the Z-direction.