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US 6,272,002 B1Granted
Electrostatic holding apparatus and method of producing the same
AssigneeShin-Estu Chemical Co., Ltd.
InventorsHiroshi Mogi, Toshimi Kobayashi
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AssigneeShin-Estu Chemical Co., Ltd.
InventorsHiroshi Mogi, Toshimi Kobayashi
Estimating the term…
There is disclosed an electrostatic holding apparatus in which a voltage is applied to an electrode formed of a conductive layer disposed on an insulator layer and covered with an insulating dielectric layer in order to cause the insulating dielectric layer to electrostatically attract an object. The electrostatic holding apparatus is formed of a sintered body in which a thermal expansion mitigating layer is disposed between the insulating dielectric layer and the conductive layer and/or between the conductive layer and the insulator layer. The insulating dielectric layer, the conductive layer, the insulator layer, and the thermal expansion mitigating layer are superposed and press-formed in an unfired state to obtain a green body, which is then sintered to obtain the sintered body. An insulating dielectric layer, a conductive layer and an insulator layer are united while differences in coefficient of thermal expansion among these layers are minimized in order to prevent generation of inter-layer delamination, cracks, and the like, and in order to prevent generation of distortion or warping on the electrostatic attraction surface to thereby increase the electrostatic attraction force. Further, the electrostatic holding apparatus has an excellent capability of allowing removal of an object at the time of stopping application of voltage and an increased withstand voltage.
An electrostatic holding apparatus in which a voltage is applied to an electrode formed of a conductive layer disposed on an insulator layer and covered with an insulating dielectric layer in order to cause said insulating dielectric layer to electrostatically attract an object, wherein the electrostatic holding apparatus is formed of a sintered body in which a thermal expansion mitigating layer having a coefficient of thermal expansion between that of said conductive layer and that of said insulating dielectric layer and said insulator layer is disposed between said insulating dielectric layer and said conductive layer and/or between said conductive layer and said insulator layer, and directly joined to those layers;
A method of producing an electrostatic holding apparatus in which a voltage is applied to an electrode formed of a conductive layer disposed on an insulator layer and covered with an insulating dielectric layer in order to cause said insulating dielectric layer to electrostatically attract an object, said method comprising the steps of:
A method of producing an electrostatic holding apparatus in which a voltage is applied to an electrode formed of a conductive layer disposed on an insulator layer and covered with an insulating dielectric layer in order to cause said insulating dielectric layer to electrostatically attract an object, said method comprising the steps of:
Dependencies are inferred from the claim text.
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1. Field of the Invention
The present invention relates to an electrostatic holding apparatus, and more particularly to an electrostatic holding apparatus useful for a process performed during fabrication of semiconductor devices, liquid-crystal devices, etc., which apparatus can strongly attract and hold a conductive, semiconductive, or insulating object by means of electrostatic force at any temperature ranging from a low temperature to a high temperature, and which enables easy attachment/detachment of the object. The present invention also relates to a method of producing such an electrostatic holding apparatus.
2. Description of the Related Art
FIG. 1 is a vertical cross-sectional view showing an example of an electrostatic holding apparatus according to the present invention.
FIG. 2 is a vertical cross-sectional view showing a second example of an electrostatic holding apparatus according to the present invention.
FIG. 3 is a vertical cross-sectional view showing a third example of an electrostatic holding apparatus according to the present invention.
Embodiments of the present invention will next be described in detail; however, the embodiments should not be construed as limiting the invention.
The inventors of the present invention considered that an electrostatic holding apparatus must have means for absorbing differences in coefficient of thermal expansion among an insulating dielectric layer, a conductive layer, and an insulator layer in order to prevent generation of distortion, warping, cracks, and the like in the attraction surface of an electrostatic attraction portion formed through integration of these layers and in order to prevent generation of inter-layer delamination and cracks within the electrostatic attraction portion, and found that when the electrostatic holding apparatus is formed of a sintered body in which a thermal expansion mitigating layer is disposed between the insulating dielectric layer and the conductive layer and/or between the conductive layer and the insulator layer, defects such as inter-layer delamination and cracks are not produced within the sintered body, and neither distortion nor warping is generated on the surface of the sintered body, thereby enabling production of a high-performance electrostatic holding apparatus that generates a strong electrostatic attraction force, enables smooth attachment and removal of an object, and has a high withstand voltage and a long service life. Based on this concept and through thorough investigation of other conditions, the present invention was completed.
FIG. 1 shows a vertical cross-sectional view of an electrostatic holding apparatus 1 according to a first example of the present invention.
Clutches or holding devices using electrostatic attraction
Using electrostatic chucks: details of electrostatic chucks
For supporting or gripping: using electrostatic chucks
Chucks or sockets: with magnetic or electrostatic means
Term ended 2 Dec 2018 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.