JP3664794B2 - Cooling and heating equipment for semiconductor processing liquid - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a cooling / heating device for a semiconductor processing liquid, and more particularly to the structure of a cooling / heating unit of a thermostatic device used for temperature control of a corrosive chemical solution or the like.
[0002]
[Prior art]
The cooling and heating device used for the semiconductor processing liquid is configured to bring the processing liquid into contact with the heat exchange substrate and to cool or heat the processing liquid through the heat exchange substrate.
[0003]
When using highly corrosive chemicals such as semiconductor processing solutions, the reaction rate varies not only greatly depending on the temperature of the solution, but it is also used to form fine elements, so even a slight amount of impurities can have a significant effect on device characteristics. Will give. For this reason, it is always necessary to pay close attention to the control of the liquid temperature, and it is necessary to use a high-purity material having high resistance to the semiconductor processing liquid as the heat exchange substrate material.
[0004]
Conventionally, as a cooling and heating device for such a semiconductor processing liquid, a stainless steel plate having a fluororesin coating applied to the processing liquid contact surface has been used. Since the gas itself permeates, the treatment liquid and the gas permeate through the coating, though slightly, and as a result, various inconveniences as shown below occur.
[0005]
That is, the treatment liquid and its gas that have reached the stainless steel react with the stainless steel to newly generate a gas, and the gas generated by this reaction pushes up the fluororesin coating to form a space. This space reduces the heating / cooling efficiency, and the gas pressure causes cracks in the coating, so that the treatment liquid comes into direct contact with the stainless steel, and a large amount of metal ions generated by the reaction between the treatment liquid and the stainless steel are treated. There was a problem of mixing in the liquid.
[0006]
In view of this, the present inventor has proposed a semiconductor processing liquid cooling and heating device in which at least the semiconductor processing liquid contact surface side of the heat exchange substrate is made of high-purity silicon carbide ceramics (Japanese Utility Model Publication No. 1-332362).
[0007]
This silicon carbide ceramic has excellent resistance to chemicals such as semiconductor processing liquids, and even if it reacts slightly, the silicon carbide components are silicon and carbon, so they are harmful ions for semiconductors. Never become.
[0008]
However, since a binder is used at the time of molding in ceramics, it is inevitable that some components in the binder are included as impurities. For this reason, although it is a very small amount, there is an unavoidable concern that this will elute in the semiconductor processing solution.
[0009]
Furthermore, a cooling and heating apparatus is also proposed in which at least the treatment liquid contact surface side of the cooling and heating unit is coated with a silicon carbide film formed by a CVD method (chemical vapor deposition method), that is, a CVD silicon carbide film. Application No. 3-33128).
[0010]
In addition, a coating with a silicon carbide film formed by a PVD method such as a sputtering method has been proposed (Japanese Patent Application No. 5-79759).
[0011]
According to the structure covered with these silicon carbide films, the material that can be used as the substrate material is not limited to the silicon carbide ceramic, and therefore there is an advantage that the workability becomes easy. In addition, CVD silicon carbide films do not use binders that cause impurities, and are highly pure and extremely resistant. In particular, CVD silicon carbide films contain alkali metal and heavy metal impurities that are harmful in semiconductor processing solutions. The rate can be 5 ppm or less.
[0012]
[Problems to be solved by the invention]
However, when the CVD method is used, if an attempt is made to form a CVD silicon carbide film having no pinholes, the film thickness must be increased, and a great deal of time is required for the formation. Further, if the formation time is to be shortened, a method such as raising the substrate temperature is taken, and there is a problem that the film quality is deteriorated, for example, the film surface becomes rough. Since the film surface is hermetically sealed using an O-ring, if it is rough, the hermeticity is lowered, and liquid leakage occurs. Therefore, conventionally, a method of performing mirror processing after forming a CVD silicon carbide film has been taken, but this has a problem that it causes an increase in cost and cannot avoid contamination of the surface by processing. .
[0013]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a semiconductor processing liquid cooling and heating apparatus that is inexpensive, does not contain harmful impurity components, is easy to process, does not generate particles, and has high reliability. And
[0014]
[Means for Solving the Problems]
Accordingly, a first feature of the present invention is that in the cooling / heating apparatus for semiconductor processing liquid configured to bring the semiconductor processing liquid into contact with the heat exchange substrate to cool or heat, the heat exchange substrate has at least a processing liquid contact surface. The side is composed of a graphite substrate coated with an amorphous carbon layer.
[0015]
Desirably, the amorphous carbon layer may be formed by heat-treating the surface of the graphite substrate, or a resin film is coated on the surface of the graphite substrate, and the amorphous carbon layer is formed by heat-treating the resin film. It may be. Furthermore, an amorphous carbon layer may be formed by a CVD method.
[0016]
A second feature of the present invention is that the heat exchange substrate is made of amorphous carbon. Desirably, a reinforcing plate for reinforcing the heat exchange substrate may be provided.
[0017]
[Action]
According to the said structure, formation of an uneven | corrugated | grooved part etc. can be easily achieved by using a graphite substrate with easy workability. In addition, an amorphous carbon layer is formed by heat-treating the surface of the molded graphite substrate, thereby making it possible to obtain a precise and good mirror surface without pinholes and not to transmit chemicals and vapors thereof. , Become reliable. In addition, it has extremely high chemical resistance and does not generate particles. The amorphous carbon layer on the surface of the graphite substrate can be obtained by applying heat energy or the like. However, if a heat treatment is performed in a state of being covered with a resin film, a smoother and more reliable amorphous carbon film can be obtained. . Moreover, you may form in a base-material surface by a vapor phase growth layer etc.
[0018]
In any case, since the base material is made of graphite or amorphous carbon instead of metal, so-called high-purity treatment can be performed by a vapor phase cleaning method in addition to wet cleaning with chemicals. Impurity removal can be achieved.
[0019]
In addition, the amorphous carbon film formed using the base material from which impurities have been removed in this way is particularly useful in the case of using a processing material or a carbon base material that does not contain impurities. The heavy metal impurity content can be 5 ppm or less, and the purity can be extremely high.
[0020]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIGS. 1 and 2, the cooling and heating device of the embodiment of the present invention is that the heat exchange substrates 1 and 2 are made of a graphite substrate, and the surface is coated with amorphous carbon to prevent reaction with the semiconductor processing chemical solution. Features.
[0021]
In other words, this cooling and heating apparatus is composed of a graphite substrate 20 and heat exchange substrates 1 and 2 whose surfaces are covered with amorphous carbon 21 are arranged to face each other via a side wall 3 made of a fluororesin. In this cooling and heating chamber, temperature control is performed on, for example, a semiconductor processing chemical solution led out from the processing container through a pipe or the like.
[0022]
Further, this apparatus is configured to be cooled or heated by the thermo modules 5 and 6, respectively, and the heat radiation side of the thermo modules 5 and 6 is cooled by cooling water introduced through the cooling pipes 7 and 8, respectively. The heat dissipating blocks 9 and 10 are brought into contact with each other. When the semiconductor processing chemical is introduced into the cooling and heating chamber through the first pipe 11, the semiconductor processing chemical is cooled or heated in the cooling and heating chamber 4 and then returned to the processing container through the second pipe 12. Furthermore, the periphery of the cooling and heating unit is hermetically sealed with an O-ring O made of a fluorine resin on the liquid contact surface.
[0023]
In forming this heat exchange substrate, after processing a high purity graphite substrate having an alkali metal / heavy metal content of 5 ppm or less into a desired shape, the surface is reacted with hydrogen fluoride gas to cause impurities such as metal elements. By evaporating (contaminants) as fluoride, it is highly purified, and after application of resin, etc., it is placed in a reactor heated to a desired temperature, and the carbon in the resin is amorphized by heat treatment, and an amorphous carbon layer Form. If heat treatment is performed in the state where the resin film is formed in this way, the resin is impregnated on the unevenness of the surface of the base material so that the resin is amorphized in a smooth state, and a smoother surface state can be obtained.
[0024]
In the apparatus using the heat exchange substrate formed in this way, the heat exchange substrate does not come into contact with the treatment chemical solution to mix impurities, and no particles are generated. Temperature control can be performed. This apparatus exhibits sufficient resistance against many acids such as hydrofluoric acid, nitric acid, phosphoric acid, sulfuric acid, and hydrochloric acid that are frequently used as semiconductor processing solutions.
[0025]
Since the surface of the heat exchange substrate is close to a mirror surface, the heat exchange substrate is sealed by the O-ring O so as to have extremely good airtightness, and there is no liquid leakage.
[0026]
Further, the graphite used as the base material is preferably a high-density graphite with as few pores as possible. Particularly, when the one having a densified surface is used, the workability is good and the mirror finish is easy, and the amorphous carbon layer Since it is formed by surface reaction with a film thickness of about 5 to 10 μm, this mirror surface can be maintained well, and there is no fear of peeling due to temperature change or the like.
[0027]
In the above embodiment, a resin is applied to the surface of the graphite substrate and a treatment by heat treatment is performed to form an amorphous carbon layer. However, the graphite substrate itself may be made amorphous by heat treatment to form an amorphous carbon layer. Alternatively, an amorphous carbon layer may be formed on the surface of the graphite substrate by vapor phase growth.
[0028]
Furthermore, in the above embodiment, the amorphous carbon layer is formed on the surface of the graphite substrate. Alternatively, the base material may be formed of amorphous carbon. For example, as shown in FIG. 3, the heat exchange substrates 1 and 2 may be made of amorphous carbon 30 having a thickness of 1 mm to 3 mm. In this case, a metal plate with good thermal conductivity may be used in combination as the reinforcing plate.
[0029]
Moreover, the side wall body may use a graphite substrate having a similar amorphous carbon layer formed on the surface, and the shape thereof can be appropriately modified.
[0030]
Furthermore, in the above embodiment, the thermo module is used as the means for cooling or heating the processing liquid, but it goes without saying that other cooling and heating means may be used instead of the thermo module. Absent.
[0031]
【The invention's effect】
As described above, according to the cooling and heating apparatus for semiconductor processing liquid of the present invention, a heat exchange substrate is formed by processing a graphite base material into a desired shape, and an amorphous carbon layer is formed on a necessary surface. Therefore, processability is good and manufacturing is extremely easy. In addition, since the polishing process can be easily performed, a smooth flat surface can be easily obtained, which is high. In addition, a dense surface can be obtained, there is no gas permeation, and the chemical resistance is extremely high. Further, extremely high flatness can be obtained, and a state close to a mirror surface can be obtained. Sealed so as to be extremely good, and no liquid leaks. Furthermore, it can be highly purified, does not generate particles, and is extremely inexpensive.
[Brief description of the drawings]
FIG. 1 is a diagram showing a cooling and heating apparatus for a semiconductor processing liquid according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a main part of the heat exchange substrate.
FIG. 3 is a cross-sectional view of a main part of a heat exchange substrate according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heat exchange board 2 Heat exchange board 3 Side wall body 4 Cooling heating chamber 5 Thermo module 6 Thermo module 7 Cooling pipe 8 Cooling pipe 9 Heat radiation block 10 Heat radiation block 11 1st piping 12 2nd piping OO ring 20 Graphite Substrate 21 Amorphous carbon layer 30 Amorphous carbon substrate 31 Metal reinforcing plate

Claims (3)

In a cooling / heating apparatus for a semiconductor processing liquid configured to bring a semiconductor processing liquid into contact with a heat exchange substrate to cool or heat,
A cooling / heating apparatus for semiconductor processing liquid, wherein the heat exchange substrate is made of a graphite base material formed by coating at least the processing liquid contact surface side with an amorphous carbon layer. In a cooling / heating apparatus for a semiconductor processing liquid configured to bring a semiconductor processing liquid into contact with a heat exchange substrate to cool or heat,
The cooling and heating apparatus for semiconductor processing liquid, wherein the heat exchange substrate is made of amorphous carbon. The cooling / heating apparatus for semiconductor processing liquid according to claim 2, further comprising a reinforcing plate that reinforces the heat exchange substrate.

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