Electricity: electrical systems and devices – Electric charge generating or conducting means – Use of forces of electric charge or field
Reexamination Certificate
2002-04-12
2004-02-17
Dinkins, Anthony (Department: 2831)
Electricity: electrical systems and devices
Electric charge generating or conducting means
Use of forces of electric charge or field
C361S233000
Reexamination Certificate
active
06693790
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a static electricity chuck apparatus and a semiconductor producing apparatus having the static electricity chuck apparatus for absorbing and holding a semiconductor substrate which can be preferably applied to various film-forming processes, plasma etching processes, ion implantation processes, ion doping processes, and the like in production of a semiconductor device, and the invention also relates to a static electricity chuck apparatus and a semiconductor producing apparatus having the static electricity chuck apparatus which can control a temperature of a surface of an absorbed body and which has excellent heat transfer performance and durability, and which has high adhesion with respect to a work piece.
2. Description of the Related Art
Conventionally, in a producing process of a semiconductor device, static electricity chuck is used for holding a semiconductor substrate in a film forming apparatus for forming a thin film on the semiconductor substrate, an etching apparatus for making fine work, or an ion doping apparatus. In this static electricity chuck, an electrode is embedded in an insulating layer, its upper surface is defined as a holding surface of the substrate, direct current is applied between the electrode and the substrate placed on the holding surface so that absorbing force called Coulomb force by dielectric polarization or Johnson-Rahbeck force by fine leakage current is generated, and the substrate is absorbed and held by the holding surface.
According to Japanese Patent Application Laid-open No. 6-349938 for example, a wafer which is a work piece is absorbed and held by static electricity by a static electricity chuck sheet on a susceptor provided in a hermetic processing chamber. A wafer absorbing surface of the static electricity chuck sheet is provided with a plurality of gas supplying holes, inert gas such as He supplied from the gas supplying holes is dispersed into a gas dispersion groove formed between the static electricity chuck sheet and the wafer, and the gas is exhausted from an exhaust hole through a gas recovering groove formed in an outer periphery of the gas dispersion groove. By enhancing the specific thermal conductivity between the wafer and the static electricity chuck sheet, a temperature distribution difference of the wafer is suppressed, gas is prevented from leaking, and the wafer is processed with high precision.
According to Japanese Patent Application Laid-open No. 7-335630 for example, a gap between a wafer and a stage of a static electricity chuck having heating or cooling function is not set uniformly, and mixture gas comprising gas of excellent thermal conductivity and gas of inferior thermal conductivity such as He gas and Ar gas is introduced into the gap. By changing the mixture ratio of gases, a distribution of overall heat transfer coefficient between the wafer and the stage is changed and temperature distribution of the wafer is changed, or a contact surface or space between the wafer and the stage is divided into a plurality of regions, and temperature distribution of the wafer is changed by individually controlling gas pressure in each region. With this structure, the wafer is uniformly heated and cooled, the wafer temperature can be made uniform at the time of production of the semiconductor device, and a semiconductor device which is finer and has high performance can be produced.
As an electricity insulating layer of the static electricity chuck, it is proposed to use ceramic such as alumina and high polymer material such as polyimide and silicone rubber, and such an insulating layer has partially been brought into actual use as described in Japanese Patent Applications Laid-open No. 7-106300, No. 9-298233, No. 2000-113850, and No. 2000-286332.
According to the Japanese Patent Application Laid-open No. 7-106300, an exposing surface of the electricity insulating layer comprising high polymer organic film is coated with fluoroplastics to enhance the plasma resistance of the electricity insulating layer. According to Japanese Patent Application Laid-open No. 2000-113850, various ceramics or glasses are used for the electricity insulating layer, and the exposing surface is coated with silicone resin such as PFTE, methylphenyl vinyl and phlorosilicone, which has resistance to plasma and excellent heat resistance, chemical resistance and aging resistance, as anti-corrosive insulating film.
In Japanese Patent Application Laid-open No. 2000-286332, a metal conductive film is coated with a pair of insulating films such as polyimide resin film so that the conductive film is sandwiched from its opposite surfaces over the entire surface. An upper surface and all side surface of the chuck body obtained in this manner and a surface of a periphery of the chuck body of a mounting stage on which the chuck body is placed and fixed are coated with protecting film comprising tetrafluoride resin or trifluoride resin, and an exposing surface of the periphery of the chuck body of the mounting stage is further coated with a protecting ring.
With this structure, it is described that corrosion is not generated on the static electricity chuck and periphery of its mounting stage by any etching such as down flow-type etching and reactive ion etching, and life of the static electricity chuck apparatus is not shortened.
Japanese Patent Application Laid-open No. 9-298233 discloses a static electricity chuck in which an electrode is disposed on a first insulating layer comprising heat conductive silicone rubber on a metal support plate, a second insulating layer comprising heat conductive silicone rubber having hardness of 85 or lower and surface roughness of 5 &mgr;m or lower is formed on the electrode to dissipate heat, adhesion between the electrode and the substrate is enhanced, contact thermal resistance is suppressed to lower level, and a temperature of the substrate is set uniformly and constantly with high precision.
According to Japanese Patent Application Laid-open No. 2000-113850, an electricity insulator of a static electricity chuck is made of silicone rubber, an electricity insulating film such as diamond-like carbon, fluoroplastics and polyimide, which has higher mold releasing performance than silicone rubber has, is formed on a surface of this electricity insulator made of silicone rubber, and separating performance of the wafer is enhanced without lowering heat transfer performance between the wafer and the static electricity chuck.
Moreover, according to Japanese Patent Application Laid-open No. 11-163109, the static electricity chuck constitutes a wafer holding apparatus which comprises a wafer holding base body whose upper surface of ceramic body having an inside electrode constituting a static absorbing electrode, a heater electrode, and plasma generating electrode is holding surface of the wafer; and a base body comprising a porous ceramic body whose thermal expansion difference between the wafer holding base body and the ceramic body constituting the wafer holding base body is 3×10
−6
/° C. or lower and having a pore into which metal is charged. The base body is bonded to a lower surface of the wafer holding base body through wax material mainly comprising aluminum, thereby constituting the wafer holding apparatus. Therefore, when the base body is bonded to a metal temperature control apparatus having cooling or heating function, it is possible to bond them strongly without deteriorating heat transfer characteristics of the bonded portions.
By the way, like the static electricity chuck disclosed in Japanese Patent Application Laid-open No. 11-163109, if the wafer holding surface is constituted by ceramic, the ceramic is obtained by sintering powder, and solids having high hardness come into contact with each other. Therefore, a gap as small as micro unit is generated in the contact surfaces between the wafer and the wafer holding surface, contact thermal resistance is increased, and since air in the gap disappears in vacuum
Kadotani Kan-ichi
Matsuki Teruyuki
Sugihara Motohide
Bell Boyd & Lloyd LLC
Dinkins Anthony
Komatsu Ltd.
Thomas Eric
LandOfFree
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