Patent ID: 8238072

Claim:
A method to attract a substrate comprising steps of: providing a bipolar electrostatic chuck comprises: a first electrode; a second electrode; and an insulating material comprising an upper insulating layer, an inter-electrode insulating layer, and a lower insulating layer, wherein the upper insulating layer, the first electrode, the inter-electrode insulating layer, the second electrode, and the lower insulating layer are positioned in the order of distance from a substrate attracting plane, the first electrode is formed in a comb-like configuration, and when the insulating material is viewed from a side cross-sectional view, the first electrode has a plurality of gaps, and the second electrode has a plurality of areas that are not overlapped with the first electrode; and applying voltage between the first electrode and second electrode, so as to generate electric lines of force which extend from the first electrode to the second electrode, though the gaps of the first electrode and reaching the substrate attracting plane, wherein the first and second electrodes are positioned in different horizontal planes, when said bipolar electrostatic chuck is viewed from a side cross sectional view, said electric lines of force generate a gradient force whereby the substrate is attracted to a surface of the insulating material as the substrate attracting plane, wherein the second electrode is formed in a plane having a given planar area, a part of the second electrode is overlapped with the first electrode in a normal line direction of the substrate attracting plane, a electrode width (z) of the first electrode and an inter-electrode gap (z) of the first electrode are made equal to each other, (z) is in a range of 0.15 to 0.5 mm, and the inter-electrode insulating layer has a thickness of 1 to 1000 μm.