Electric heating – Heating devices – Combined with container – enclosure – or support for material...
Reexamination Certificate
2001-04-16
2002-09-03
Paik, Sang (Department: 3742)
Electric heating
Heating devices
Combined with container, enclosure, or support for material...
C118S725000, C219S544000
Reexamination Certificate
active
06444957
ABSTRACT:
CLAIM OF PRIORITY
This application claims priority of Japanese Patent Application No. 2000-126587, filed Apr. 26, 2000, and Japanese Patent Application No. 2000-154589, filed May 25, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a heating apparatus that is housed within a reaction chamber, which is used for heating an object to be heated, such as a wafer or the like, and is able to achieve marked improvements with respect to both its heating efficiency and product life.
2. Relevant Art
Conventionally, as an example of a heating apparatus that is housed within a reaction chamber and used for heating an object to be heated such as a wafer or the like, a heating apparatus is known, which comprises a heating block that is divided into two parts. Among these two divisions of the aforementioned heating block, the heating block onto which the object to be heated is placed (hereinafter referred to as “loading plate”) comprises a material that has a comparatively high coefficient of thermal conductivity, such as stainless steel, iron or the like. The other heating block (hereinafter referred to as “support plate”) comprises a material that displays a lower coefficient of thermal conductivity than the material comprising said loading plate, such as ceramics, chinaware, building stone, or the like. In addition, the aforementioned conventional heating apparatus comprises a structure in which a heating element is sandwiched in between the aforementioned loading plate and support plate. In this manner, this heating apparatus is able to heat the aforementioned loading plate by means of concentrating the heat generated by the heating element to the loading plate, and consequently displays a high heating efficiency.
In addition, as another example of a conventional heating apparatus, a heating apparatus is known which comprises a structure in which a single layer or multiple layers of a heat insulating material are provided in between a surface heating member, formed by means of burying a heating element within a ceramics sintered body possessing a superior thermal conductivity, corrosion resistance, and plasma resistance; and a support member, which supports this heating member and connects to a reaction chamber, wherein this heat insulating material limits the heat conducted from the aforementioned surface heating member to said support member.
FIG. 5
is a schematic outline showing the cross-sectional structure of an example of a conventional heating apparatus. The structure of this heating apparatus
1000
will be described in the following. This heating apparatus
1000
comprises a surface heating member
103
, a heating element
108
, an electrode plate
104
, a heat insulating material
113
, and a support member
102
.
As shown in
FIG. 5
, heating apparatus
1000
internally comprises a structure in which a single layer of a heat insulating material
113
is sandwiched in between a surface heating member
103
, comprising a heating element
108
having a predetermined shape (e.g., spiral-shaped) and a disk-shaped electrode plate
104
for generating plasma, and a support member
102
. In this heating apparatus
1000
, both the heat insulating material
113
and surface heating member
103
, as well as the heat insulating material
113
and support member
102
are joined in an airtight manner.
The surface heating member
103
is equipped with a first ceramics sintered body
103
a
for holding heating element
108
, a second ceramics sintered body
103
b
for holding electrode plate
104
, and a third ceramics sintered body
103
c
onto which the object to be heated is placed. The first ceramics sintered body
103
a
and second ceramics sintered body
103
b,
as well as, the second ceramics sintered body
103
b
and third ceramics sintered body
103
c
are respectively joined in an airtight manner by means of bonding layers
110
and
107
, each respectively comprising a heat-resistant bonding agent.
In addition, as seen in
FIG. 5
, heating element
108
is loaded within concave member
112
, which is provided along the shape of heating element
108
, on the upper surface of the first ceramics sintered body
103
a
in the figure; and electrode plate
104
is loaded within concave member
111
, which is provided on the upper surface of the second ceramics sintered body
103
b
in the figure.
One pair of heater feeding electrodes
109
is connected to the aforementioned heating element
108
, and a high-frequency/direct current voltage application electrode
105
is connected to electrode plate
104
. In addition, a thermocouple
106
, one terminal of which is inserted into surface heating member
103
, is provided in heating apparatus
1000
for measuring the temperature within surface heating member
103
.
However, in this type of heating apparatus wherein the loading plate comprises a material that has a comparatively high coefficient of thermal conductivity, such as stainless steel, iron or the like, while the support plate comprises a material that displays a lower coefficient of thermal conductivity than that of the material comprising said loading plate, such as ceramics, chinaware, building stone, or the like, due to the inferior plasma resistance of the stainless steel, iron, etc. comprising the loading plate, there exist problems with respect to the short product life of the heating apparatus.
In addition, in the aforementioned heating apparatus, it is difficult to match the coefficient of thermal expansion of the support plate, which is able to decrease the amount of heat dissipated, and the coefficient of thermal expansion of the loading plate, and thus a difference in these coefficients of thermal expansion inevitably appears. As a result, the durability of the bonding interface between the support plate and the loading plate is insufficient, thereby contributing to the problem of the short product life of this heating apparatus.
In addition, in the construction of the heating apparatus
1000
shown in
FIG. 5
, problematic restrictions on the structural material of the heat insulating material
113
exist due to the exposure of the side surface of the heat insulating material
113
to the anti-corrosive atmospheric gas, plasma, and the like. As a result, in addition to the restrictions on the structural material of the heat insulating material
113
, since it is difficult to approximate the difference in the coefficients of thermal expansion of surface heating member
103
and insulating material
113
, or difference in the coefficients of thermal expansion of insulating material
113
and support plate
102
, the structure of the aforementioned heating apparatus is extremely complex, leading to a problematic increase in cost.
In order to solve the aforementioned problems, the present invention provides a heating apparatus that displays both a high heating efficiency and a long product life.
Specifically, it is an object of the present invention to provide a heating apparatus comprising a superior plasma resistance, wherein an improvement of the durability of the interface generated by the difference in the coefficients of thermal expansion of the loading plate and support plate is realized while maintaining a high heating efficiency.
In addition, the present invention provides a heating apparatus with a superior heating efficiency, which is free of any restrictions on the structural material of the heat insulating material and is, moreover, easily manufactured at low cost, wherein the product life is further increased.
SUMMARY OF THE INVENTION
In order to achieve the aforementioned objects, the present invention utilizes the following construction.
The present invention provides a heating apparatus characterized in comprising: a loading plate onto which an object to be heated is placed; a support plate that is integrated into a single body with said loading plate; a heating element which is sandwiched in between said loading plate and said support plate; and at least one pair of electrodes, one terminal of which is connected
Endou Kazunori
Hashimoto Masayuki
Ishizuka Masayuki
Kitagawa Takao
Nagata Tsuyoshi
Paik Sang
Sierra Patent Group Ltd.
Sumitomo Osaka Cement Co., Ltd
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