US Patent 11626310 Electrostatic chuck

According to one embodiment, an electrostatic chuck includes a ceramic dielectric substrate, a base plate, and a first porous part. The ceramic dielectric substrate has a first major surface and a second major surface on opposite side from the first major surface. The base plate supports the ceramic dielectric substrate and includes a gas feed channel. The first porous part is provided at a position between the base plate and the first major surface of the ceramic dielectric substrate. The position is opposed to the gas feed channel. The first porous part includes a plurality of sparse portions each including a plurality of pores. The plurality of sparse portions are spaced from each other. Each of the plurality of sparse portions extends in a direction inclined by a prescribed angle with respect to a first direction from the base plate to the ceramic dielectric substrate.