The inventive concept provides a cooling unit. In an embodiment, the cooling unit comprises: a cooling plate with a seating surface; a pin member arranged at the cooling plate and supporting a substrate; a decompression hole formed on the seating surface; a decompression path formed within the cooling plate and connected to the decompression hole; a decompression member for decompressing the decompression path; and a controller for controlling the decompression member, wherein the controller controls the decompression member to decompress a space between the substrate and the seating surface of the cooling plate and thereby adjusting a distance between the substrate and the seating surface of the cooling plate.