Patent ID: RE42175

Claim:
An electrostatic chucking stage for electro-statically chucking an object, comprising: a dielectric plate on which the object is chucked; a chucking electrode to which voltage for dielectrically polarizing the dielectric plate is applied; a moderation layer provided between the dielectric plate and the chucking electrode, and having a thermal expansion coefficient between a thermal expansion coefficient of the dielectric plate and a thermal expansion coefficient of the chucking electrode; a covering layer provided on the chucking electrode at a side opposite to the dielectric plate so that the chucking electrode is sandwiched by the moderation layer and the covering layer, said covering layer having a thermal expansion coefficient between the thermal expansion coefficient of the dielectric plate and the thermal expansion coefficient of the chucking electrode; and wherein the moderation layer and the covering layer have structures comprising metal filled into porous bulks made of ceramic, wherein the thermal expansion coefficients of the moderation layer and the covering layer are obtained by adjusting volume opening ratios of the porous bulks, wherein the chucking electrode has a flange part at a periphery thereof and is fixed to a metallic main body by screwing at the flange part, and the covering layer is inserted between the chucking electrode and the main body in an interfacial recess inner to the flange part, wherein the moderation layer and the covering layer are separated so as not to cover an end of the electrode, and wherein the electrode and the metallic main body are electrically conducted through the metal filled into the porous ceramic of the covering layer to apply the voltage for chucking without a connecting line through the covering layer.