Electric heating – Heating devices – With heating unit structure
Reexamination Certificate
2002-06-14
2003-02-04
Walberg, Teresa (Department: 3742)
Electric heating
Heating devices
With heating unit structure
C219S552000, C219S541000, C219S411000, C219S444100, C219S460100, C338S322000, C118S724000, C118S725000
Reexamination Certificate
active
06515264
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a heater and, more particularly, to a rod-shaped heater or a plate-like heater which uses a carbon wire heating element with a quartz glass member sealed therein.
In various heat treatment atmosphere in oxidation, diffusion or chemical vapor deposition (CVD) treatments conducted in the semiconductor manufacturing process, a strict temperature control is required.
Further, in the semiconductor manufacturing process, a strict temperature control is also required for a wet etching agent, a grinding agent or the like as used in other cleaning or grinding processes.
For this temperature control in such processes, a rod-shaped heater or a plate-like heater is widely used.
As an example of such heaters, there has been proposed a heater which has a heating element made of tungsten material, the outside of said heating element being covered by a quartz glass tube.
Since such a rod-shaped heater or a plate-like heater is directly dipped in a storage tank which stores a wet etching agent, a grinding agent or the like, there is a technical problem left unsolved that once the quartz glass tube covering the heating element should break, said wet etching agent or said grinding agent will be subjected to metallic contamination, leading to contamination of the wafers which are going to be ground or cleaned.
Even if said quartz glass tube is not broken, there still is a gradual metallic contamination of the wet etching agent or the grinding agent by way of the quartz glass heater from said heating element.
The inventors have already proposed in Japanese Patent Application No. 10-254513 a heater for semiconductor manufacturing which employs a carbon wire heating element that may be used advantageously as compared to said metallic heating element.
Said carbon wire heating element is manufactured by binding very fine carbon filaments into a carbon fiber bundle and weaving a plurality of such carbon fiber bundles.
Said carbon wire heating element have a small heat capacity as to provide an excellent temperature rising and decreasing characteristics as compared to the conventional metallic heating element and an excellent heat resistance in a non-oxidizing atmosphere.
Further, since a plurality of fine carbon filaments are woven into carbon fiber bundles, the thus manufactured carbon wire heating element has advantages such as more flexibility than a heating element of a solid carbon material and it is easy to work the material into various structure or shapes.
SUMMARY OF THE INVENTION
The present invention is made to solve the above mentioned technical problem which the rod-shaped heater or a plate-like heater conventionally faces by use of said carbon wire heating element and its objective is to provide a heater suited to raise the temperature of the wet etching agent, the grinding agent or the like by dipping directly into the storage tank.
Particularly, the present invention has it an objective to provide a heater which can prevent the metallic contamination of the wet etching agent, the grinding agent or the like, and which has a mechanical strength against any breakage in the event of direct dipping into the storage tank of the wet etching agent or the grinding agent.
In order to solve the above mentioned technical problem, the present invention essentially provides in one aspect thereof a heater comprising a large diameter glass tube; a carbon wire heating element sealed in said large diameter glass tube and having opposite ends; a small diameter glass tube charged with compressed wire carbon members at opposite ends thereof, said compressed wire carbon members tightly holding said opposite ends of the carbon wire heating element therebetween; and a sealed terminal section having connection lines for power supply held between said carbon wire material, said connection lines and said carbon wire heating element being electrically connected to each other by way of said wire carbon members.
Also in order to solve the above mentioned technical problem, the present invention essentially provides in another aspect thereof, a heater comprising a carbon wire heating element having opposite ends; a small diameter glass tube charged with compressed wire carbon members at opposite ends thereof, said compressed wire carbon materials tightly holding said opposite ends of the carbon wire heating element therebetween such that said small diameter glass seals carbon wire heating element therein; and a sealed terminal section having connection lines for power supply held between said carbon wire material, said connection lines and said carbon wire heating element being electrically connected to each other by way of said wire carbon members.
In this connection, it is preferable that said large diameter glass tube and said small diameter glass tube are formed of quartz glass.
In order to solve the above mentioned technical problem, the present invention essentially provides in a further aspect thereof, a heater a plate-like glass member; a carbon wire heating element sealed in said plate-like glass member and having opposite ends; a small diameter glass tube section charged with compressed wire carbon members, said compressed wire carbon members tightly holding said opposite ends of the carbon wire heating elements therebetween; and a sealing terminal section having connection lines for power supply held between said carbon wire members, said connection lines and said carbon wire heating element being electrically connected to each other by way of said wire carbon members.
Thus, the present invention relating to the heater is characterized in that the connection lines are held in a compressed manner between the wire carbon members. Therefore, the carbon contents of the wire carbon performs a reducing reaction to prevent the connection lines from being oxidized with the result that any generation of sparks accompanying the oxidation of the connection lines.
Further, since the carbon wire heating elements and the connection lines are attached to the wire carbon members at their compressed portions, the connection are prevented from becoming loose due to the high temperature of the carbon wire heating element, thus assuring a good electrical connection.
Further, since the carbon wire heating element is used, a wet etching agent, a grinding agent or the like is prevented from metallic contamination spreading by way of the glass tube from the heating element.
It is preferable that said aid wire carbon members and said carbon wire heating element are held in a compressed state to extend substantially in parallel to an axis of said small diameter quartz glass tube section.
Further, it is preferable that each of said wire carbon members and said carbon wire heating element is prepared by binding a plurality of carbon fibers into a carbon fiber bundle and weaving a plurality of such carbon fiber bundles into a knitted cord or a braid.
In this way, since said wire carbon members and said carbon wire heating element are accommodated in parallel to the axis of the small diameter glass tube in a compressed state, the connection between said wire carbon members and said carbon wire heating element will not become loose, thus assuring a good electrical connection.
Particularly, said wire carbon members and said carbon wire heating element which are composed of knitted cords or braids woven from a plurality of fiber bundles each of which is prepared by binding carbon fibers have elasticity in the direction of the small diameter glass tube to assure a positive retention of the connection lines without the likelihood of becoming loose with the result that a good electrical connection is maintained.
It is preferable that said small diameter glass tube section accommodates one or more carbon wire heating elements therein and is charged with a plurality of wire carbon members and it is also preferable that said wire carbon members and said carbon wire heating elements are formed of an identical material to each other, the number of said wire carbon members is five times
Konn Tomio
Makiya Toshiyuki
Nagata Tomohiro
Nakao Ken
Osanai Hisaei
Foley & Lardner
Fuqua Shawntina T.
Toshiba Ceramics Co. Ltd.
Walberg Teresa
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