JP3947661B2 - MoSi2 plate heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heater made of MoSi2 which can heat with accuracy without troubles of short-circuiting by enabling to tightly set sintering heaters of MoSi2 on a bottom wall, an upper wall, an inner wall or the like of a heating device or the like. SOLUTION: The heater is one of plate shape made of MoSi2 having a bent part without seams, of which, each bent part is bent in the width direction of the plate-shaped heater.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a MoSi ₂ plate heater that can be manufactured at a low cost, with high heater integration, high temperature and easy temperature control, and less deformation such as deformation and short circuit during heating.
The MoSi ₂ plate heater used in the present specification includes a heater mainly composed of MoSi ₂ in which an electrical resistance is increased by adding an insulating oxide or the like to pure MoSi _{2 to} MoSi ₂ .
[0002]
[Prior art]
Since the heater mainly composed of molybdenum disilicide (MoSi ₂ ) has excellent oxidation resistance, it has been commercially available since 1950-1960 as an ultra-high temperature heater especially used in the atmosphere or in an oxidizing atmosphere, and has a wide range of uses up to now. Used in. This heater contains 70 wt% or more of MoSi ₂ as a main component.
Conventionally, a heater used in many fields such as glass industry and ceramic firing is a heat generating part (in general, "heat generating part" means a part where the diameter of the heater that mainly generates heat when energized is thin (other than the terminal part). .) Has a single U-shape (two shank type) and is suspended from the ceiling or side wall of the furnace, and the maximum operating temperature of the furnace reaches 1700-1850 ° C.
[0003]
Recently, along with miniaturization of semiconductor devices, shortening of device manufacturing time and energy saving, heaters mainly composed of MoSi ₂ have been used in semiconductor manufacturing equipment such as CVD equipment and diffusion furnaces that conventionally used metal heating elements. It has come to be.
The heater mainly composed of MoSi ₂ has excellent heat resistance characteristics, can have a surface load about 10 times that of a metal heating element, and has a great feature capable of rapid heating and heating.
In general, a heat treatment furnace used in a semiconductor manufacturing apparatus is required to have a highly accurate temperature characteristic such as strictly controlling the temperature distribution in the furnace.
[0004]
As shown in FIG. 9, a heater mainly composed of MoSi ₂ is a U-shaped heater in which a rod-shaped heater material is bent into a U shape and terminal portions are welded to both ends of the heat generating portion. In FIG. 9, the U-shaped heater 31 includes a heating part 32, a welding part 33, a grip (terminal) part 34, and an electrode part 35.
However, since the temperature of the terminal portion is larger than that of the heat generating portion, in a furnace that requires precise temperature control as described above, as shown in FIG. A heater having a shape (multi-shank) in which a large number of U-shaped heat generating portions bent from a material are connected has been proposed.
The shape of such a multi-connected heater reduces the number of terminal portions penetrating through the inside and outside of the furnace, so heat loss radiated from the terminal portions can be reduced, and has a certain effect on the uniformity of the furnace temperature. It is thought that there is.
Recently, there has been a demand for a heater that can increase heater integration and accurately control heat. However, a heater obtained by bending a rod-shaped heater material or a welded heater is liable to be deformed (heated) during heating, and there is a problem that an accident such as a short circuit occurs when the bent portion is dense. Therefore, there is a problem that it is practically difficult to manufacture a high-precision heater with improved integration.
[0005]
[Problems to be solved by the invention]
The present invention, bottom wall, top wall of the heating apparatus MoSi ₂ made heater, to allow closely installed on the side wall or the like, there is no accident such as a short circuit, to provide a MoSi ₂ made heater can be accurately heated.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors have intensively studied to increase the degree of integration by making the MoSi ₂ heater into a plate shape, and to accurately control the temperature without causing an accident such as a short circuit. I learned that I can do it.
The present invention is based on this finding,
1. MoSi ₂ powder, which is the raw material for the heater, is kneaded with a binder containing a thermoplastic resin, extruded to form a rod, and then molded by fitting it into a mold, and then the molded body is degreased and sintered. MoSi ₂ plate heater having a seamless U-shaped continuous waveform obtained by bending each U-shaped bent portion in the plate width direction of the plate heater, and the bent portions are arc-shaped or angular-shaped , and the providing MoSi ₂ made plate-like heater, wherein the ratio of plate width to thickness (plate width / thickness) is 2 or more.
[0007]
The present invention also provides
2. _2. The MoSi ₂ plate heater as described in 1 above, wherein the power is supplied with the terminal portion of the plate heater wider than the heat generating portion.
3. 3. The MoSi ₂ plate heater according to 1 or 2 above, wherein power is supplied with the thickness of the terminal portion of the plate heater being thicker than that of the heat generating portion.
4). Providing MoSi ₂ made plate heaters according to the heat generation portion of the plate-like heater in any of the above 1 to 3, characterized in that for feeding directly the chuck by metal electrodes with water cooling.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
When manufacturing the MoSi ₂ plate heater of the present invention, first, MoSi ₂ powder, which is a raw material of the heater, is mixed with a binder, and this mixture is kneaded, for example, into a rod shape, fitted into a mold, and pressed into a plate shape. To do. The binder is desirably used by containing a thermoplastic resin. When a thermoplastic resin is contained in the binder, the strength after molding (green strength) is particularly improved, and the molding accuracy can be improved and the thin plate can be molded.
In this case, the rod-like mixture is a plastic product and only needs to be loaded with a capacity corresponding to the plate-like depression of the mold or slightly larger. Excess MoSi ₂ mixture after press molding is removed. The important point here is that each bent portion is molded into a shape that bends in the plate width direction of the plate heater.
[0009]
Several methods can be cited as the molding method. Part 1 is a method in which a mixed powder of MoSi ₂ powder and a binder is filled in a mold and heated and press-molded. Part 2 is a mixture obtained by kneading a mixed powder of MoSi ₂ powder and a binder into a clay, and a mixture obtained thereby. As a third method, there is a method of kneading a mixed powder of MoSi ₂ powder and a binder, fitting an extruded bar into the mold, and press-molding. However, when a thermoplastic binder is used, it is necessary to appropriately adjust the material and mold temperature from kneading to molding.
In the present invention, any method may be adopted, and it can be appropriately selected and used according to the shape to be molded. In either case, it is desirable to fill and mold the substrate so that no defects such as bubbles remain inside the substrate.
Next, this molded body is degreased, primary sintered and energized and heated to produce a MoSi ₂ plate heater in which the bent portion is bent in the plate width direction of the plate heater.
[0010]
It is important that the bent portion bends in the plate width direction of the plate heater, and structurally, the plate is hardly deformed in the width direction when used as a heater. Therefore, the space | interval of a plate-shaped heater can be made small and an integration degree can be raised remarkably. The ratio of plate width to thickness (plate width / thickness) of the plate heater is 2 or more, preferably 4 or more. The larger the ratio, the more effective the plate heater having the same thickness is in preventing deformation.
Thus, the MoSi ₂ plate heater having a high degree of integration can be densely installed on the bottom wall, top wall, side wall, etc. of a heating device or the like. In addition, since there is almost no deformation in the plate width direction, there is no accident such as a short circuit, and since the heater is highly integrated, the uniformity of the furnace temperature distribution can be improved more effectively.
[0011]
Furthermore, even with the same current density as the bar, the plate heater has the advantage that the heating surface area of the heat generating part in the direction of the product to be heat-treated becomes large, so that the heating efficiency can be increased and the temperature uniformity of the product can be further increased. .
When the plate heater of the present invention has a continuous waveform, it can be formed not only in a U-shape but also in a shallow U-shape, V-shape or sine curve, and the wave height can be changed. These merely change the degree and length of bending, and the U-shaped continuous waveform of the present invention encompasses all of these waveforms.
The cross-sectional shape of the plate heater does not necessarily have to be a rectangle (the corners are right-angled). For example, the corner shape of the plate heater is rounded (R is added) and can be easily separated (released) from the mold after molding. Can be.
The overall shape of the cross section of the plate heater may be an elliptical shape, a semicircular shape, a track shape, or the like. There is no restriction | limiting in particular in the cross-sectional shape of the plate-shaped heater of this invention, Any of said shape etc. can be used.
[0012]
When the plate heater of the present invention is used, what is important is the power feeding method, particularly the structure of the terminal portion. It is necessary to sufficiently lower the temperature of the terminal portion to be fed with respect to the heat generating portion of the plate heater. Therefore, according to the present invention, power is supplied with the terminal portion of the plate heater wider than the heat generating portion, or the thickness of the terminal portion of the plate heater is thicker than that of the heat generating portion. This suppresses heating of the terminal portion by increasing the cross-sectional area of the terminal portion and decreasing the resistance.
Instead of the above, power can be supplied by directly chucking the heat generating portion of the plate heater with a metal electrode having a water cooling function. In the present invention, these power feeding methods can be arbitrarily selected according to the heating conditions by the heater.
Furthermore, it is desirable to fix the terminal part of the plate heater or the heat generating part near the terminal part with a material having heat insulating properties and insulating properties. As a result, accidents due to contact of terminals and the like can be effectively prevented.
[0013]
【Example】
Next, specific examples of the plate-like MoSi ₂ plate heater of the present invention will be described with reference to the drawings. The following examples are for the purpose of showing preferred examples so that the invention can be easily understood, and are not limited to these examples. That is, modifications or other examples based on the technical idea of the present invention are naturally included in the present invention.
[0014]
Example 1
FIG. 1 shows an example of a MoSi ₂ plate-like heater having a shape in which S-shapes are connected symmetrically in a left-right direction so as to fit almost uniformly in one circle as a whole.
The plate width of the heat generating portion 2 of the heater 1 was 10 mm, the plate thickness was 1.8 mm, and the S-shaped interval was 6 mm. Both ends of the heat generating portion 2 of the heater 1 extend in the downward direction in the figure, and the terminal portion 3 is attached to the tip.
Since it is necessary to lower the temperature of the terminal portion 3, the width is gradually increased from the joint portion with the heat generating portion 2 as shown in FIG. 1, for example, a wide terminal portion 3 having a width of 20 mm can be obtained. The width of the terminal portion 3 is twice the width of the heat generating portion 2. However, in this case, the heat generating portion 2 and the terminal portion 3 have the same thickness.
Both the terminal portions 3 and 3 are fixed with a heat-resistant and insulating material 4 such as alumina as shown in FIG. 2, and an aluminum spray 5 is applied to the tip in order to improve electrical conductivity. it can. Further, as shown in FIG. 3, it can be structured such that it can be energized by chucking with a holder 6 connected to the cable 7.
[0015]
(Example 2)
FIG. 4 shows an example of a plate heater made of MoSi ₂ having a shape in which bending is reversed approximately every semicircle symmetrically so as to fit almost uniformly in one circle as a whole.
The heating part 12 of the heater 11 has a plate width of 5 mm, a plate thickness of 1.5 mm, and an interval of 6 mm. Both ends of the heat generating portion 12 of the heater 11 extend in the downward direction in the figure, and the terminal portion 13 is attached to the tip.
Since it is necessary to lower the temperature of the terminal portion 13, as shown in FIG. 5, for example, a plate having the same width of 5 mm and a plate thickness of 1.5 mm can be overlapped on both sides of the heat generating portion 12 to form the terminal portion 13. The thickness of the terminal portion 13 is three times the thickness of the heat generating portion 12. However, in this case, the widths of the heat generating portion 12 and the terminal portion 13 are the same.
Both the terminal portions 13 and 13 are fixed with heat-resistant and insulating materials 14 and 14 such as alumina as shown in FIG.
In the same manner as in Example 1, in order to improve the electrical conductivity, an aluminum spray 15 can be applied to the tip thereof. FIG. 7 shows a cross section of the terminal portions 13 and 13 fixed with a material 14 having heat resistance and insulation. Further, for example, as in FIG. 3, the structure is such that it can be energized by chucking with a holder connected to the cable.
[0016]
(Example 3)
FIG. 8 shows an example of a MoSi ₂ plate-like heater having a shape such that swans are symmetrically facing each other, and the shape is such that, as a whole, the swans are almost uniformly contained in one circle.
The plate width of the heat generating portion 22 of the heater 21 was 20 mm, the plate thickness was 2.4 mm, and the plate interval was 10 mm. Both ends of the heat generating part 22 of the heater 21 protrude in parallel from the center of the figure to the back side of the paper. The tip is chucked directly by a metal electrode 23 with a water cooling function so that power can be supplied. Reference numeral 24 denotes a support for the heater 21, reference numeral 25 denotes a water-cooled tube, and reference numeral 26 denotes a power feeding cable.
[0017]
【The invention's effect】
The MoSi ₂ plate heater of the present invention can be densely installed on the bottom wall, top wall, side wall, etc. of a heating device, etc., is not deformed when used as a heater, and is electrically shorted by a short circuit in the width direction, etc. This makes it possible to prevent accidents such as the above, thereby improving the temperature uniformity of the furnace, and has an excellent effect of facilitating temperature control.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a MoSi ₂ plate-like heater shown in Example 1 in which S-shapes are connected symmetrically left and right so as to fit almost uniformly in one circle as a whole.
FIG. 2 is a perspective view showing a structure in which a terminal portion is fixed with a heat-resistant and insulating material such as alumina.
FIG. 3 is a cross-sectional explanatory view of a structure in which a terminal portion is chucked with a holder connected to a cable.
FIG. 4 is an explanatory diagram of a MoSi ₂ plate heater shown in Example 2 in which the bending is reversed approximately every semicircle symmetrically so as to fit almost uniformly in one circle as a whole.
FIG. 5 is a perspective view of a terminal portion in which plates of the same width are overlapped on both sides of a heat generating portion.
FIG. 6 is an explanatory diagram of a structure in which both terminal portions are fixed with a heat-resistant and insulating material such as alumina.
FIG. 7 is a view showing a cross section of a terminal portion fixed with a material having heat resistance and insulation.
FIG. 8 is an explanatory diagram of a MoSi ₂ plate heater of Example 3 having a shape such that swans are symmetrically facing each other and fit almost uniformly in one circle as a whole.
FIG. 9 is an explanatory diagram of a conventional U-shaped heater in which terminals are welded to both sides of a U-shaped heat generating portion.
FIG. 10 is an explanatory view showing a state in which a conventional U-shaped heater member is connected and an arc heater is attached to the inside of a furnace.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 11, 21 Heater 2, 12, 22 Heat generating part 3, 13 Terminal part 4, 14 Material 5 which has heat resistance and insulation 5, 15 Aluminum spraying 6 Holder 7, 26 Feeding cable 23 Metal electrode 24 with a water cooling function 24 Heater Support base 25 Water-cooled tube

Claims (4)

MoSi ₂ powder, which is the raw material for the heater, is kneaded with a binder containing a thermoplastic resin, extruded to form a rod, and then molded by fitting it into a mold, and then the molded body is degreased and sintered. MoSi ₂ plate heater having a seamless U-shaped continuous waveform obtained by bending each U-shaped bent portion in the plate width direction of the plate heater, and the bent portions are arc-shaped or angular-shaped And a ratio of plate width to thickness (plate width / thickness) is 2 or more, MoSi ₂ plate heater. _2. The MoSi ₂ plate heater according to claim 1 , wherein the power is supplied by making the terminal portion of the plate heater wider than the heat generating portion. The MoSi ₂ plate heater according to claim 1 or 2, wherein power is supplied with the thickness of the terminal portion of the plate heater being thicker than that of the heat generating portion. The MoSi ₂ plate heater according to any one of claims 1 to 3, wherein the heating portion of the plate heater is directly chucked by a metal electrode with a water cooling function to supply power.

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