Bipolar Electrostatic Chuck

Abstract

A bipolar electrostatic chuck which has excellent dielectric breakdown strength and provides excellent attracting performance. The bipolar electrostatic chuck eliminates difficulty in dismounting a sample from a sample attracting plane as much as possible after application of a voltage to electrodes is finished. The bipolar electrostatic chuck is provided with a first electrode and a second electrode in an insulator and permits a surface of the insulator to be the sample attracting plane. The insulator has the first electrode, an interelectrode insulating layer and the second electrode in this order from the sample attracting plane in the depth direction. The second electrode has a region not overlapping with the first electrode in a normal line direction of the sample attracting plane.

Description

TECHNICAL FIELD [0001] The present invention relates to a bipolar electrostatic chuck that electrostatically attracts and holds a sample. BACKGROUND ART [0002] There has been widely employed an electrostatic chuck that electro-statically attracts and holds a sample such as a wafer or a glass in a device that is used in a semiconductor manufacturing process required in forming an integrated circuit on a semiconductor wafer such as silicon, such as an etching device, a plasma processing device used for formation of a thin film through a chemical vapor deposition (abbreviated to CVD), an electron exposure device, an ion rendering device, an ion implanting device, or in a device that is used in a process of manufacturing a liquid crystal display panel which is employed for a TV screen or a computer display such as a substrate bonding device or an ion doping device which is used in press-inserting liquid crystal in an insulating substrate such as a glass. This is because the electrostati...

AI Technical Summary

Benefits of technology

[0060] The bipolar electrostatic chuck according to the present invention is structured to have the first electrode, the interelectrode insulating layer, and the second electrode in the order of distance from the sample attracting plane in the depth direction of the insulating material. With the above structure, the bipolar electrostatic chuck according to the present invention is excellent in electrical insulation, and is capable of shortening the distance between the first electrode and the second electrode as much as possible, thereby exercising the excellent attracting performance. As a result, the bipolar electrostatic chuck according to the present invention is excellent in the flatness of the held sample, and exercises the sufficient attracting performance with respect to a glass substrate that exceeds 1 m×1 m so as to accept the recent large size glass substrate, a silicon wafer that is equal to or more than 300 mm in diameter, or the like. Also, the bipolar electrostatic chuck according to the present invention is capable of exercising the excellent attracting performance. As a result, the bipolar electrostatic chuck according to the present invention is capable of conducting in the low voltage operation, is advantageous in the economical viewpoint, eliminates the discharge problem as much as possible, and is high in the reliability.

[0061] In addition, the bipolar electrostatic chuck according to the present invention reduces an area in which the first electrode and the second electrode are overlapped with each other when the sample attracting plane is viewed in the depth direction as much as possible, thereby making it possible to reduce the capacitance of the electrostatic chuck, and also making it possible to eliminate the difficulty of dismounting the sample from the sample attracting plane after turning off the voltage that has been applied to both of the electrodes. Further, in the case where an electrically conductive layer is formed on the surface of the insulating material, and the surface of the electrically conductive layer serves as the sample attracting plane, the bipolar electrostatic chuck according to the present invention is capable of reducing the time constant of the electrostatic chuck regardless of the area in which the first electrode and the second electrode are overlapped with each other in the normal line direction of the sample attracting plane. The bipolar electrostatic chuck according to the present invention is also capable of eliminating the difficulty of dismounting the sample from the sample attracting plane after a voltage has been applied to both of the electrodes.

Problems solved by technology

However, in the case where the distance between the electrodes that are adjacent to each other is shortened, there arises a problem of a discharge limit.

Also, voids occur when an adhesive agent for forming an adhesive layer that fixes the respective insulating layers to each other or the insulating layers with the electrodes is bonded.

As a result, the dielectric breakdown strength is remarkably deteriorated between the adjacent electrodes.

For that reason, in the conventional bipolar electrostatic chuck that narrows the interval between the electrodes as described above, a voltage that can be actually applied is limited, and there arises such a problem that a sufficient attracting performance, i.e., gradient force, cannot be exercised because a weight per unit area is increased with respect to a semiconductor wafer that is increasingly enlarged diameter in size or a glass substrate that is used for a liquid crystal TV or a flat panel display which are increasingly enlarged in size.

On the other hand, in the case where an insulating sample is attracted by the electrostatic chuck, there arises such a problem that a sample is difficult to dismount from the attracting plane of the sample due to the residual charges even if a voltage that is applied to the electrodes is turned off.

In particular, this problem becomes severe as the sample is increasingly enlarged in size.

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