ELECTROSTATIC CHUCK MADE OF CERAMIC

PURPOSE:To prevent the attachment of dust to a material to be sucked by forming recess parts in a sucking surface, forming a contact part with the material to be sucked so that the area ratio with respect to the entire sucking surface is 10-30%, and specifying the surface roughness of the contact part as 0.8S or less. CONSTITUTION:In an electrostatic chuck, an inner electrode 2 is provided on a ceramic planar body 1. The chuck is fixed to a base plate 4 with a bonding agent 3. The upper surface of the ceramic planar body 1 is made to be a sucking surface 1a. Recess parts 1b are formed in the sucking surface 1a. The area ratio of a contact part 1c with a material to be sucked 6 is made to be 10-30%. The surface roughness of the contact part 1c is made to be 0.8S or less. Namely, the contact part 1c is made to be the mirror surface, and the area ratio of the contact part 1c with respect to the entire sucking surface is made to be in the specified range. Thus, sufficient sucking force in use is maintained, and recess parts are formed in the sucking surface 1a. Therefore, dust is hard to attach to the material to be sucked 6, and releasing property can be enhanced.