Substrate holding unit and substrate processing apparatus

A substrate holding unit, comprising:

• a core body having a first surface configured to support a substrate and a second surface opposite to the first surface;
• an electrode layer disposed on the core body and including pyrolytic graphite providing heat to the substrate;
• and
• a ceramic insulating layer covering the electrode layer and disposed on the first surface and the second surface of the core body, and including pyrolytic boron nitride,
• wherein a first surface of the ceramic insulating layer on the first surface of the core body includes a cubic crystal structure in at least a portion thereof, and includes a hexagonal crystal structure in at least another portion thereof, and an area of the cubic crystal structure is 0.1 to 0.2 times an area of the hexagonal crystal structure.

A substrate processing apparatus, comprising:

• a process chamber providing an internal space for processing a substrate;
• a support unit disposed in the internal space and configured to support the substrate;
• and
• a gas supply unit supplying process gas to the internal space,
• wherein the support unit comprises:
• a core body having a first surface for supporting the substrate and a second surface opposite to the first surface;
• an electrode layer disposed on the first surface and the second surface of the core body;
• and
• a ceramic insulating layer covering the electrode layer and disposed on the first surface and the second surface of the core body,
• wherein a first surface of the ceramic insulating layer on the first surface of the core body includes a cubic crystal structure in at least a portion thereof, and includes a hexagonal crystal structure in at least another portion thereof.