JP2007214287A5 - - Google Patents

Claims (4)

Alumina is 99.4 wt% or more, titanium oxide is greater than 0.2 wt% and 0.6 wt% or less, bulk density is 3.97 g / cm ³ or more, volume resistivity is 10 ⁸ to 10 ¹¹ Ωcm at room temperature, and alumina particles An electrostatic chuck comprising a dielectric for electrostatic chuck having a structure in which titanium oxide is segregated at grain boundaries. _2. The electrostatic chuck according to claim 1, wherein aluminum titanate (Al ₂ TiO ₅ ) does not exist in the grains and the grain boundaries of the alumina particles. The electrostatic chuck according to claim 1 , wherein the electrostatic chuck is used at a low temperature of 100 ° C. or less. A ratio of the total area of the top surfaces of the plurality of convex portions to the area of the dielectric surface, which is composed of a dielectric having a smooth surface on which a plurality of convex portions are formed and the object to be adsorbed is placed on the top surface of the convex portions The electrostatic chuck according to any one of claims 1 to 3 , wherein the height is 0.001% or more and less than 0.5%, and the height of the convex portion is 5 to 15 µm.