Substrate holding unit and substrate processing apparatus

A substrate support unit, comprising:

• a ceramic body having a surface for supporting a substrate, and including an inner region and an outer peripheral region surrounding the inner region, the ceramic body including a ceramic material;
• a first heat generating resistor disposed within the ceramic body in the inner region and a second heat generating resistor disposed within the ceramic body in the outer peripheral region, each of the first and second heat generating resistors having a wire structure;
• first and second inner coating layers directly contacting outer surfaces of the first and second heat generating resistors, respectively, the first and second inner coating layers including a material the same as a material of the ceramic body;
• and
• first and second outer coating layers surrounding the first and second inner coating layers, respectively, the first and second outer coating layers including aluminum nitride,
• wherein when viewed in cross-section, the first and second inner coating layers concentrically surround the first and second heat generating resistors, respectively, and the first and second outer coating layers concentrically surround the first and second inner coating layers, respectively.

A substrate support unit, comprising:

• a ceramic body having a first surface for supporting a substrate and a second surface opposite to the first surface, the ceramic body including aluminum nitride (AlN);
• a heat generating resistor disposed in the ceramic body, and including molybdenum (Mo), the heat generating resistor having a wire structure;
• a first inner coating layer surrounding the heat generating resistor and a second inner coating layer surrounding the first inner coating layer, each of the first and second inner coating layers including molybdenum (Mo);
• and
• an outer coating layer surrounding the first and second inner coating layers, the outer coating layer including aluminum nitride doped with magnesium (Mg),
• wherein when viewed in cross-section, the first inner coating layer concentrically surrounds the heat generating resistor and directly contacts an outer surface of the heat generating resistor, the second inner coating layer concentrically surrounds the first inner coating layer and directly contacts an outer surface of the first inner coating layer, and the outer coating layer concentrically surrounds the second inner coating layer and directly contacts an outer surface of the second inner coating layer.