Layered ceramic/metallic assembly, and an electrostatic chuck using such an assembly

The present invention generally relates to a ceramic/metallic assembly including a ceramic layer and a metallic layer bonded thereto, and an electrostatic chuck using such an assembly. The present invention more particularly relates to a ceramic/metallic assembly, and an electrostatic chuck using such an assembly which are characterized by the material of the ceramic layer and the bonding arrangement between the ceramic and metallic layers. A combination of a ceramic layer essentially consisting of magnesia ceramic material and a metallic layer is proposed for a layered assembly for use in applications such as electrostatic chucks which are subjected to thermal stress. A combination of magnesia ceramic material and ferritic stainless steel is preferred because of the similarities of the thermal expansion coefficients of these materials. When a larger difference in the thermal expansion coefficients exists between the selected combination of materials, a damper layer having an intermediate thermal expansion coefficient may be used so as to accommodate the difference in the thermal expansion of the two layers.