JP4330775B2 - Carbon parts - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a carbon component made of a carbon material.
[0002]
[Prior art]
Conventionally, various carbon parts for manufacturing semiconductors using carbon materials are known.
As a method for manufacturing such a carbon component, for example, a method is generally used in which a solid block material larger than a desired product is prepared, and the block material is cut to obtain a final product. And, according to this conventional method, it is characteristic that a product having relatively high processing accuracy can be obtained.
[0003]
[Problems to be solved by the invention]
However, the conventional carbon parts and the manufacturing method thereof have some problems as follows.
[0004]
That is, since the conventional carbon parts are dense solid bodies made of carbon, they become heavier when they are large and difficult to handle during transportation. In addition, since an apparatus using such components is often used at a high temperature, the heating power cost is increased due to an increase in heat capacity.
[0005]
Further, in the above conventional carbon part manufacturing method using a block material, it is necessary to cut a considerable amount of the block material. Therefore, it takes time for the cutting process and is inferior in productivity. In addition, since material is wasted by cutting, the yield of the material is low and the material cost is high.
[0006]
Furthermore, when a carbon part having a thick part and a thin part (for example, a carbon part for a semiconductor manufacturing apparatus) is to be obtained by the above-described conventional carbon part manufacturing method, cracks are likely to occur in the thin part during cutting. .
[0007]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a carbon component that is light in weight and easy to handle, with low waste of materials during manufacture, low cost, and easy manufacture. There is.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is a substrate obtained by firing a molded product obtained by suction molding using a slurry in which carbon fibers are suspended in a liquid, fiber length is from the deposition layer deposited on an oriented state of carbon fibers is 1 mm to 2 mm, and the substrate is a bulk density ^{0.2g / cm 3 ~0.3g / cm 3} , the surface of the substrate A coating layer made of pyrolytic carbon, which is a high-purity and hard substance that covers the substrate, and the penetration thickness penetrated into the substrate of the coating layer at the edge of the substrate is other than the edge The gist of the carbon component is that the thickness is greater than the permeation thickness of the coating layer penetrating into the substrate.
[0009]
According to a second aspect of the present invention, in the first aspect, the carbon component is a component for manufacturing a semiconductor .
[0011]
Below, a description will be given of "action" in the present invention.
[0012]
According to invention of Claim 1, it is the base material which baked the molding obtained by the suction molding using the slurry formed by suspending carbon fiber in the liquid, Comprising : Average fiber length is 1 mm-2 mm Since the carbon fiber is composed of a deposited layer deposited in an oriented state, the porous body has a low bulk density. For this reason, it becomes light and easy to handle. Moreover, since the surface of the base material is covered with a coating layer made of pyrolytic carbon, which is a high-purity and hard substance , mechanical strength suitable for the entire carbon component is imparted. Therefore, dropping off of the carbon fiber from the surface of the substrate is prevented. In addition, when the coating layer has penetrate | infiltrated the inside of a base material, as a result of combining the layers of the carbon fiber which comprise a deposition layer with a coating layer, suitable mechanical strength is provided by carbon components.
[0013]
Also, with this structure, unlike in the case of cutting the block material, the waste of material at the time of manufacture is extremely reduced. For this reason, the yield of material becomes high and material cost is reduced. In addition, with this structure, there is no occurrence of cracks during molding, and manufacturing is relatively easy.
[0014]
Furthermore , the material substance of the coating layer can easily permeate into the inside along the layer direction of the deposited layer at the edge portion of the substrate. For this reason, the coating layer in the said location tends to be thick compared with the coating layer in the other location. Therefore, the edge portion of the substrate that is particularly prone to chipping or peeling is reinforced by the coating layer.
[0015]
According to the second aspect of the present invention, it is possible to provide a clean semiconductor manufacturing component that hardly contaminates the semiconductor.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
[First embodiment]
Hereinafter, a carbon part for semiconductor manufacture and a manufacturing method thereof according to an embodiment embodying the present invention will be described in detail with reference to FIGS.
[0018]
FIG. 1 shows a silicon single crystal pulling apparatus 1 which is a kind of semiconductor manufacturing apparatus. The apparatus 1 is for obtaining a high-purity silicon ingot by heating and melting a silicon material and then pulling silicon as a single crystal. An introduction part 3 for introducing an inert gas is provided in the upper part of the sealed body 2 constituting the silicon single crystal pulling apparatus 1. A quartz crucible 4, a crucible 5, a rotating shaft 6, a heater 7, a heat insulating cylinder 8, an upper ring 9, a lower ring 10, a bottom heat shield plate 11, a gas rectifying member 12, and the like are accommodated in the sealed body 2. . A silicon material is put into the quartz crucible 4. This quartz crucible 4 is held by a crucible 5 arranged outside thereof. The center of the bottom surface of the crucible 5 is supported from below by the rotating shaft 6. When the rotary shaft 6 is rotated by driving means (not shown), the crucible 5 associated therewith rotates. A heater 7 is disposed around the side of the crucible 5. The crucible 5 is heated by energizing the heater 7 so that the silicon material is melted. A heat insulating cylinder 8 is provided around the side of the heater 7. The heat retaining cylinder 8 is supported between the upper ring 9 and the lower ring 10. A bottom heat shield 11 for preventing heat from escaping from the bottom surface is disposed on the inner bottom surface of the sealed body 2.
[0019]
At the position directly above the quartz crucible 4, in other words, at the position where the introduction part 3 is formed in the sealed body 2, the inert gas introduced through the introduction part 3 is rectified and is introduced into the quartz crucible 4. A gas rectifying member 12 is provided for reliably guiding the gas flow. The gas rectifying member 12 of the present embodiment is a cylindrical object having a circular cross section as shown in FIG. The diameter of one end of the gas rectifying member 12 is larger than the diameter of the other end. Therefore, the shape when the gas rectifying member 12 is projected from the side is substantially trapezoidal. In other words, the gas rectifying member 12 is a tapered member having a tapered shape.
[0020]
As shown in FIG. 1, the gas rectifying member 12 is fixed to the inner side of the upper surface of the sealed body 2 with the end on the large diameter side facing downward. The diameter of the end portion on the large diameter side is preferably set to be larger than the diameter of the introduction portion 3.
[0021]
As schematically shown in FIG. 2 (b), the gas rectifying member 12 of this embodiment includes a base material 14 composed of a deposited layer in which carbon fibers 13 are deposited in layers, and a surface of the base material 14. The covering layer 15 is made of a highly pure and hard material. In the present embodiment, the coating layer 15 made of pyrolytic carbon is selected as the coating layer 15. Here, the pyrolytic carbon refers to a carbon substance that is pyrolyzed by heating a hydrocarbon gas or the like. Here, “high purity” means that the impurity concentration is 20 ppm or less, and “hard” means that the hardness is Hs70 or more.
[0022]
The covering layer 15 covers the entire surface of the base material 14. Moreover, although pyrolytic carbon which is a material substance of the coating layer 15 has penetrated to some extent inside the base material 14, it has not completely penetrated. The penetration thickness W1 into the inside of the base material of the coating layer 15 in the edge part 14a of the base material 14 is larger than the penetration thickness W2 into the base material of the coating layer 15 in a place other than the edge part. . The reason is as follows.
[0023]
That is, when the surface which cut | disconnected the gas rectification | straightening member 12 along the axial direction as shown in FIG.2 (b) is seen, the carbon fiber 13 which comprises a deposited layer is not an at random state, but the state orientated to some extent. It has become. More specifically, the carbon fibers 13 are oriented so as to be orthogonal to the thickness direction of the gas rectifying member 12. Therefore, the pyrolytic carbon easily penetrates into the inside along the layer direction of the deposited layer in the edge portion 14a of the base material 14. On the other hand, pyrolytic carbon is relatively less likely to permeate the interior of the base material 14 other than the edge portion 14a (inner peripheral surface 14b and outer peripheral surface 14c). For this reason, the coating layer 15 in the edge part 14a is thicker than the coating layer 15 in other locations. In the case of the present embodiment, the penetration thickness W1 is 3 mm to 5 mm, and the penetration thickness W2 is 1 mm to 3 mm.
[0024]
The gas rectifying member 12 is thin and has a substantially uniform thickness. In this embodiment, the thickness of the gas rectifying member 12 is set to 5 mm to 20 mm. The bulk density of the base material 14 before coating have a ^{0.2g / cm 3 ~0.3g / cm 3} , so to speak a what can say a porous body. The bulk density of the base material 14 after coating (i.e. the average bulk density of the entire gas rectifying member 12 is a finished product) is in a ^{0.5g / cm 3 ~0.8g / cm 3} . Furthermore, the average fiber length of the carbon fibers 13 is 1 mm to 2 mm, and the average fiber diameter is 12 μm to 14 μm.
[0025]
Next, an apparatus and a method for manufacturing the gas rectifying member 12 will be described.
FIG. 3 shows a suction molding device 21 used for molding the gas rectifying member 12. The suction molding device 21 includes a suction molding die 22, a suction pump 23, and an elevating means (not shown). The suction mold 22 has a suction chamber 25 having an inner shape along the shape of a desired molded article 24 and a decompression chamber 26 formed along the side and bottom surfaces of the suction chamber 25. The decompression chamber 26 side and the suction pump 23 side are communicated with each other by piping. Therefore, when the suction pump 23 is operated, the air in the decompression chamber 26 is discharged and the decompressed state is achieved. A tank 27 for storing the slurry 28 is disposed below the suction mold 22. The tank 27 or the suction mold 22 is driven in the vertical direction by lifting means.
[0026]
The side surface and the bottom surface forming the suction chamber 25 are porous mold surfaces having a large number of fine holes 29. The size of the fine holes 29 is smaller than the size of the carbon fibers 13 in the slurry 28. The fine holes 29 are provided only in the portion along the outer peripheral shape of the molded product 24.
[0027]
The decompression chamber 26 includes a relay decompression chamber 26 a located on the outer periphery of the bottom of the suction chamber 25 and a side decompression chamber 26 b located on the lateral outer periphery of the suction chamber 25. The side decompression chamber 26 b communicates with the relay decompression chamber 26 a through the suction port 30. The opening area of the suction port 30 is set so that the force for sucking the molded product 24 is substantially the same in the entire decompression chamber 26.
[0028]
Hereinafter, the manufacturing method of the gas rectification member 12 using the suction molding apparatus 21 having the above structure will be described in the order of steps.
In manufacturing the gas rectifying member 12, a suction molding process is first performed. In this suction molding step, the slurry 28 is produced by suspending the carbon fibers 13 in a liquid.
[0029]
In the present embodiment, pitch-based carbon fibers (having a diameter of 13 ± 1.3 μm and a fiber length of 1 to 2 mm) 13 are used as the carbon fibers 13. In preparing the slurry 28, MFC (pulp), a phenol resin, and starch as binder components are mixed with the pitch-based carbon fibers 13. The mixing ratio of these is 100 for carbon fiber, 5 for MFC (pulp), 5 for phenol resin and 5 for starch. The slurry 28 having the above composition is prepared by putting the carbon fiber 13 in water and stirring it, and then adding and stirring the phenol resin, MFC and starch in that order, and aggregating them.
[0030]
The slurry 28 is put in the tank 27 and the lifting means is driven to immerse the suction mold 22 in the slurry 28. In this case, the suction pump 23 is operated in advance, and the pressure state of the decompression chamber 22 is set lower than the atmospheric pressure. Then, the slurry 28 is sucked to the suction mold 22 side. Since the carbon fibers 13 in the slurry 28 are larger than the fine holes 29, the carbon fibers 13 are gradually deposited in layers on the surface of the porous mold surface. On the other hand, the liquid in the slurry 28 can pass through the fine holes 29. That is, the liquid is sucked behind the porous mold surface and reaches the decompression chamber 22 side, and is then discharged to the outside through the pipe. As a result, the carbon fiber 13 is deposited on a specific portion of the inner surface of the suction chamber 25, and a molded product 24 having a desired shape is formed.
[0031]
Next, a drying process for drying the molded product 24 obtained through the suction molding process is performed, and moisture contained in the molded product 24 is almost completely removed. Specifically, in the present embodiment, the molded product 24 is placed in a drying furnace, and drying is performed by setting the furnace temperature to a value equal to or higher than the evaporation temperature of water (here, 150 ° C.). If such a drying step is performed in advance, a good fired product can be obtained in the next firing step.
[0032]
Next, the baking process which bakes the molding 24 dried through the drying process process is performed. Specifically, in the present embodiment, firing is performed under a temperature condition of about 2000 ° C. in an inert gas atmosphere.
[0033]
Next, a purification process of the molded product 24 baked through the baking process is performed, and impurities other than the carbon material are removed from the molded product 24. Specifically, in the present embodiment, the molded product 24 is heated to a temperature of about 2000 ° C., and chlorine gas is caused to flow on the surface of the molded product 24, thereby changing impurities in the molded product 24 to chloride. Has been removed. When this step is performed, the gas rectifying member 12 finally obtained can be highly purified. Therefore, even when the gas rectifying member 12 is used in a high temperature environment, impurities are not released into the atmosphere, and the gas becomes straight.
[0034]
Finally, a coating layer forming step is performed on the purified molded article 24 (that is, the base material 14) to form a coating layer 15 made of pyrolytic carbon on the surface layer portion of the base material 14. Here, chemical vapor deposition (CVD) is adopted as a method for forming the coating layer 15.
[0035]
Specifically, the surface of the base material 14 is heated to about 1200 to 1900 ° C. in the CVD. The degree of vacuum is set to about 10 Torr to 200 Torr, and a hydrocarbon gas or a halogenated hydrocarbon gas is brought into contact with the surface of the base material 14 in the presence of hydrogen gas to cause a chemical reaction. As a result, the coating layer 15 made of pyrolytic carbon is formed on the surface of the base material 14 and at a predetermined depth from the surface, and the gas rectifying member 12 having a desired shape shown in FIG. 2 is completed.
[0036]
Therefore, according to the present embodiment, the following effects can be obtained.
(1) The gas rectifying member 12 of the present embodiment includes a base material 14 made of a deposited layer in which carbon fibers 13 are deposited in layers, and a coating layer 15 made of a high-purity and hard substance that covers the surface of the base material 14. It is made up of. And the base material 14 used for this is a porous body having a small bulk density, and is lightweight and easy to handle. The gas rectifying member 12 includes a coating layer 15. Therefore, although the base material 14 is a porous body, suitable mechanical strength is given to the gas rectifying member 12 as a whole. That is, the base material 14 is reinforced by the coating layer 15. Therefore, dropping off of the carbon fibers 13 from the surface of the base material 14 is reliably prevented. Therefore, the gas rectifying member 12 of the present embodiment is a clean semiconductor manufacturing component that hardly contaminates the semiconductor.
[0037]
Also, with this structure, unlike the conventional case where the cutting process is performed on the block material, waste of the material at the time of manufacture is extremely reduced. For this reason, the yield of material becomes high and material cost is reduced. As a result, an inexpensive gas rectifying member 12 can be obtained. Moreover, if the structure is formed of such a deposited layer, even if the gas rectifying member 12 is thin, cracks do not occur during molding. Therefore, the gas rectifying member 12 can be manufactured relatively easily.
[0038]
(2) In the gas rectifying member 12 of the present embodiment, the coating layer 15 is not only present on the surface of the base material 14 but also penetrates into the base material 14 to some extent. Therefore, as a result of the layers of the carbon fibers 13 constituting the deposition layer being bonded together by the coating layer 15, more favorable mechanical strength is imparted to the gas rectifying member 12.
[0039]
Moreover, the penetration thickness W1 into the inside of the base material of the coating layer 15 in the edge part 14a of the base material 14 is larger than the penetration thickness W2 into the base material of the coating layer 15 at other locations. . Therefore, the edge portion 14 a of the base material 14 that is particularly likely to be chipped or peeled is reinforced by the coating layer 15. For this reason, the gas rectification member 12 excellent in durability can be realized.
[0040]
Although pyrolytic carbon has penetrated into the base material 14 to some extent, it has not completely penetrated. Therefore, the material cost is reduced as compared with the case where the gas is completely infiltrated. Moreover, the incompletely penetrated product as in this embodiment is lighter than the completely penetrated product.
[0041]
(3) The coating layer 15 in the gas rectifying member 12 is made of pyrolytic carbon. In addition to being highly pure and hard, pyrolytic carbon is relatively inexpensive and can be formed relatively easily. Moreover, since the coating layer 15 made of pyrolytic carbon is the same kind of material as the base material 14 made of the carbon fiber 13, it has a high affinity with the base material 14 and can ensure a suitable bonding strength. From the above, it is possible to further reduce costs and facilitate manufacturing, and to improve durability.
[0042]
(4) The base material 14 is produced by firing a molded product 24 obtained by suction molding using a slurry obtained by suspending carbon fibers 13 in a liquid. And in order to produce such a base material 14, in this embodiment, the suction molding process using the suction molding apparatus 21 of said structure, the drying process, and the baking process are performed. Therefore, if a suction mold 22 corresponding to a desired shape is prepared, a molded product 24 having a desired shape can be obtained relatively easily. This method is particularly advantageous when a thin molded article 24 is formed. Therefore, in addition to the short time required for molding as compared with the conventional method in which cutting is performed, there is an advantage that defective products are less likely to occur because molding errors are less likely to occur.
[Second Embodiment]
Next, Embodiment 2 will be described with reference to FIG. In Embodiment 2, the crucible 5 in the silicon single crystal pulling apparatus 1 is manufactured in place of the gas rectifying member 12. As shown in FIG. 1, the shape of the gas rectifying member 12 and the crucible 5 are different. That is, since this crucible 5 has a thin part and a thick part (that is, the bottom part is thicker than the side part), the suction molding device 21 having a slightly different structure from that of the first embodiment is used here. Used.
[0043]
As shown in FIG. 4, a bottom decompression chamber 31, which is another decompression chamber, is provided between the relay decompression chamber 26 a and the bottom of the suction chamber 25. The bottom decompression chamber 31 communicates with the relay decompression chamber 26 a through the suction port 32. On the other hand, the side decompression chamber 26 b communicates with the relay decompression chamber 26 a through the suction port 33. The opening area of the suction port 32 of the bottom decompression chamber 31 is set to be larger than the opening area of the suction port 33 of the side decompression chamber 26b. Therefore, when suction is performed in the same manner as in the first embodiment, the slurry 28 is attracted more toward the bottom of the suction chamber 25 that is in contact with the bottom decompression chamber 31 having a large opening area. Therefore, the thickness of the bottom portion of the molded product 24 that becomes the crucible 5 is larger than the thickness of the side portion thereof.
[0044]
As another method for partially changing the thickness of the molded product 24, a method using a thickness adjusting plate may be implemented. In this method, the suction is temporarily stopped during the suction of the slurry 28. Then, a thickness adjusting plate is arranged at a portion to be thickened, and the slurry 28 is again sucked from the thickness adjusting plate to perform molding. As a result, the thickness of the portion where the thickness adjusting plate is present can be made larger than the thickness of the other portions.
[0045]
And if the suction molding apparatus 21 of this embodiment is used, the crucible 5 which is easy to manufacture with little waste of the material at the time of manufacture, low cost, and easy to handle can be obtained. Further, since the thickness of the molded product 24 can be partially changed relatively easily, the crucible 5 having a thin portion and a thick portion can be obtained with certainty.
[0046]
In addition, you may change embodiment of this invention as follows.
-It is not limited to the pitch-type carbon fiber 13 used in embodiment, You may produce a carbon component using carbon fibers other than a pitch-type (for example, PAN-type carbon fiber, other carbon fibers, etc.).
[0047]
It is made of high-purity and hard carbon formed by a method other than the thermal decomposition (for example, baking after applying a resin) instead of the coating layer 15 made of carbon formed by thermal decomposition by the CVD method. The covering layer 15 may be adopted. It is also possible to employ a coating layer 15 made of a high-purity and hard substance other than carbon (in other words, a high-purity and hard substance that is different from the base material), such as silicon carbide. is there.
[0048]
The carbon component is not limited to the cylindrical body as in the first embodiment or the saddle-like body as in the second embodiment, and may be, for example, a box-like body or a plate-like body.
The carbon parts of the present invention are various parts (quartz crucible 4, rotating shaft 6, heater 7, heat insulating cylinder 8, upper ring 9, lower ring) used in the silicon single crystal pulling apparatus 1 which is a kind of semiconductor manufacturing apparatus. 10, bottom heat shield 11, etc.). Of course, it may be embodied as a component in a semiconductor manufacturing apparatus other than the silicon single crystal pulling apparatus 1.
[0049]
Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiment described above are listed below.
(1) In Claim 2 , the carbon component is a crucible, a rotating shaft, a heater, a heat insulating cylinder, an upper ring, a lower ring, a bottom heat shield plate, or a gas rectifying member used in a silicon single crystal pulling apparatus. Carbon parts characterized by that.
[0051]
【The invention's effect】
As described in detail above, according to the first aspect of the present invention, there is provided a carbon component that is low in cost, easy to manufacture, and is lightweight and easy to handle. Can do.
[0052]
Furthermore, since the edge part of a base material is reinforced, it can be set as the carbon component excellent in durability.
According to the second aspect of the present invention, a clean semiconductor manufacturing component that hardly contaminates the semiconductor can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a silicon single crystal pulling apparatus according to an embodiment of the present invention.
2A is a cross-sectional view showing a gas rectifying member of the embodiment, and FIG. 2B is a cross-sectional view schematically showing an enlarged main part thereof.
FIG. 3 is a schematic view showing a suction molding apparatus used for molding the gas rectifying member of the embodiment.
FIG. 4 is a schematic view showing a suction molding apparatus having a plurality of decompression chambers in another embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 5 ... Crucible as carbon parts, 12 ... Gas rectifying member as carbon parts, 13 ... Carbon fiber, 14 ... Base material, 14a ... Edge edge of base material, 15 ... Pyrolytic carbon coating layer as coating layer, 24 ... moldings, W1, W2 ... penetration thickness.

Claims (2)

A base material obtained by firing a molded product obtained by suction molding using a slurry in which carbon fibers are suspended in a liquid, and carbon fibers having an average fiber length of 1 mm to 2 mm are deposited in an oriented state. made from the deposition layer, and the substrate bulk density of ^{0.2g / cm 3 ~0.3g / cm 3} , a coating layer made of pyrolytic carbon is a material of high purity and hard cover the surface of the substrate The penetration thickness that penetrates into the base material of the coating layer at the edge portion of the base material is larger than the penetration thickness that penetrates into the base material of the coating layer at a location other than the edge portion. Carbon parts characterized by The carbon component according to claim 1, wherein the carbon component is a component for manufacturing a semiconductor.

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