JP2010277917A - Heater for heat treatment, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heater for heat treatment of which manufacturing process is simple, cost is reduced and rigidity is high. <P>SOLUTION: The heater for heat treatment 1 is provided with a temporary calcined body 3 in which a porous body of silicon carbide is temporarily calcined and a covering material 5 consisting of an insulating material which covers the outer surface of the temporary calcined body 3. Thereby, by covering the porous temporary calcined body 3 with low rigidity with the covering material 5 consisting of insulating material, the heater for heat treatment 1 having high durability and high radiation efficiency, with a simple manufacturing process and reduced cost can be obtained. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat treatment heater and a manufacturing method thereof, and more particularly to a heat treatment heater composed of a silicon carbide sintered body that performs heat treatment for semiconductor wafers and industrial applications, and a manufacturing method thereof.

  Conventionally, molten metal silicon is infiltrated into a calcined body made of silicon carbide, and the molten metal silicon is sucked up into the calcined body by a capillary phenomenon, thereby reacting the sucked metal silicon with carbon in the calcined body. A method for manufacturing a silicon carbide sintered body for a heater to obtain silicon carbide is known (see, for example, Patent Document 1).

JP 2006-151719 A

  However, the heater described in Patent Document 1 described above has a problem that the manufacturing process is complicated and the cost is high. On the other hand, a heater obtained without impregnating molten metal silicon has a problem of low rigidity.

  An object of the present invention is to provide a heat treatment heater with a simple manufacturing process, low cost, and high rigidity, and a method for manufacturing the same.

  The first feature of the present invention is that a calcined body (calcined body 3) obtained by calcining a porous body of silicon carbide and a covering material (covering material 5) made of an insulating material covering the outer surface of the calcined body. ).

  Therefore, by coating a porous calcined body having low rigidity with a covering material made of an insulating material, a heat treatment heater having high durability and high radiation efficiency, a simple manufacturing process and low cost can be obtained.

  Another feature is that the covering material (covering material 5) is made of silica.

  Another feature is summarized in that a quartz glass plate (quartz glass plates 7 and 9) is bonded to the silicon carbide calcined body (calcined body 3).

  In another feature, the method for manufacturing a heat treatment heater according to the present invention includes a step of producing a slurry comprising a mixture containing the silicon carbide powder by dispersing the silicon carbide powder in a solvent, and molding the slurry. And calcining the dried green body to produce a calcined body (calcined body 3) and coating the outer surface of the calcined body with a coating material (coating material 5) that is an insulating material. The gist is to have.

  Another feature is that the covering material (covering material 5) is made of silica.

  The other feature is to cover the calcined body (calcined body 3) with an insulating material and then join a quartz glass plate (quartz glass plates 7 and 9) to the calcined body.

  According to the heat treatment heater and the method for producing the same according to the present invention, it is possible to obtain a heat treatment heater having high durability, radiation efficiency, a simple production process, and low cost.

It is sectional drawing of the heater for heat processing by 1st Embodiment of this invention. It is sectional drawing of the heater for heat processing by 2nd Embodiment of this invention. It is sectional drawing of the heater for heat processing by 3rd Embodiment of this invention. It is a flowchart which shows the manufacturing process of the heater for heat processing by 4th Embodiment of this invention. It is a graph which shows the relationship between the time which sends an electric current to each heater in an Example, and resistance increase rate. It is a graph which shows the relationship between the time which flows an electric current through the heater of the comparative example 1 in an Example, and resistance increase rate. It is a graph which shows the relationship between the time which flows an electric current through the heater of the comparative example 2 in an Example, and resistance increase rate. It is a graph which shows the relationship between the time which flows an electric current through the heater of the example of this invention in an Example, and resistance increase rate. It is a graph which shows the emissivity change by surface roughness about the coating material of the heater in an Example. It is a graph which shows the temperature dependence of volume resistance about the heater in an Example.

  Hereinafter, details of the heat treatment heater according to the embodiment of the present invention will be described with reference to the drawings. However, it should be noted that the drawings are schematic and the thicknesses and ratios of the material layers are different from the actual ones. Accordingly, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.

[First embodiment]
First, the heat treatment heater according to the first embodiment of the present invention will be described.

  FIG. 1 is a sectional view of a heat treatment heater according to a first embodiment of the present invention. As shown in FIG. 1, the heat treatment heater 1 according to the present embodiment includes a calcined body 3 and a covering material 5 that covers the outer surface of the calcined body 3.

  The calcined body 3 can be produced by drying and calcining a porous body formed by a method such as casting, press molding, or extrusion molding using silicon carbide powder and carbon powder. . Further, by dispersing silicon carbide powder, dispersion material, binder, plasticizer, etc., a slurry made of a mixture of these is prepared, the slurry is cast-molded, and the dried green body is calcined and temporarily fired. A sintered body can also be produced. Moreover, a granulated powder is produced from the slurry, the granulated powder is press-molded, and the dried green body is calcined to produce a calcined body.

  The porosity of the calcined body 3 is preferably 25% or more, particularly preferably 30% to 40%. The covering material 5 is preferably an insulating material such as silica.

  Below, the effect by embodiment of this invention is demonstrated.

  (1) A heat treatment heater 1 according to the present embodiment includes a calcined body 3 obtained by calcining a porous body of silicon carbide, and a coating material 5 made of an insulating material that coats the outer surface of the calcined body 3. ing. Therefore, by covering the porous calcined body 3 having low rigidity with the covering material 5 made of an insulating material, it is possible to obtain a heat treatment heater 1 having high durability and radiation efficiency, a simple manufacturing process, and low cost. it can.

  (2) Since the covering material 5 is made of silica having a high light transmittance, the heat treatment heater 1 having a high radiation rate can be obtained.

[Second Embodiment]
Next, a heat treatment heater according to a second embodiment of the present invention will be described. However, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  FIG. 2 is a sectional view of a heat treatment heater according to the second embodiment of the present invention.

  The heat treatment heater 11 includes a calcined body 3 whose outer surface is coated with a coating material 5 made of silica, and a quartz glass plate 7 bonded to the calcined body 3 via the coating material 5. The quartz glass plate 7 can be applied to any glass other than quartz glass that has heat resistance and transparency during heat treatment.

  Below, the effect by embodiment of this invention is demonstrated.

  (1) Since the quartz glass plate 7 having a high light transmittance is joined to the silicon carbide calcined body 3, the durability is further improved while maintaining a high radiation rate.

[Third embodiment]
Next, a heat treatment heater according to a third embodiment of the present invention will be described. However, the same components as those in the first and second embodiments described above are denoted by the same reference numerals and description thereof is omitted.

  FIG. 3 is a sectional view of a heat treatment heater according to a third embodiment of the present invention.

  The heater 21 for heat treatment includes a calcined body 3, a quartz glass plate 7 placed on the upper surface of the calcined body 3, and a quartz glass plate 9 disposed under the lower surface of the calcined body 3. The fusing agent 10 is provided outside the outer peripheral surface of the calcined body. That is, the calcined body 3 is sandwiched between a pair of quartz glass plates 7 and 9 from above and below and is covered with the adhesive 10.

  Below, the effect by embodiment of this invention is demonstrated.

  (1) Since the quartz glass plates 7 and 9 having a high light transmittance are joined to the silicon carbide calcined body 3, the durability is further improved while maintaining a high radiation rate.

[Fourth embodiment]
Next, a method for manufacturing a heat treatment heater according to a fourth embodiment of the present invention will be described. However, the same components as those in the first to third embodiments described above are denoted by the same reference numerals and description thereof is omitted.

  FIG. 4 is a flowchart showing the manufacturing process of the heat treatment heater according to the present embodiment. As shown in FIG. 4, the manufacturing method of the heater for heat treatment according to the present embodiment includes a step of producing a slurry composed of a mixture containing silicon carbide powder by dispersing silicon carbide powder in a solvent, It includes at least a step of preparing the calcined body 3 by calcining the green body that has been molded and dried, and a step of coating the outer surface of the calcined body 3 with a coating material 5 that is an insulating material. A heat treatment heater 1 manufactured by this method has a structure shown in FIG. Hereinafter, a manufacturing method using cast molding will be described, but the molding method is not limited to this, and press molding, extrusion molding, or the like is also possible.

(1) Step of preparing slurry of mixture First, silicon carbide powder is dispersed in a solvent to prepare a slurry made of a mixture containing silicon carbide powder. Specifically, the slurry is prepared from a mixture of these by dispersing silicon carbide powder, a dispersion material, a binder, a plasticizer, and the like.

  Next, stirring and mixing are performed for 6 hours to 48 hours, particularly 12 hours to 24 hours using a stirring and mixing means such as a mixer or a planetary ball mill. This is because if the stirring and mixing are not sufficiently performed, the pores are not uniformly dispersed in the green body.

(2) Step of obtaining a green body The obtained slurry is poured into a casting mold. Then, after leaving and demolding, the solvent is removed by heating or natural drying under a temperature condition of 40 ° C to 60 ° C. In this manner, a green body having a predetermined size, that is, a silicon carbide molded body in which uniform pores are present by removing the solvent from the slurry is obtained.

(3) Calcination step The obtained green body is heated from 1500 ° C. to 1950 ° C. in a vacuum atmosphere over a period of about 12 to 18 hours. When the heating temperature is less than 1500 ° C., degreasing becomes insufficient. The temperature increase rate is set to 100 ° C./1 hr or less in order to prevent explosion due to rapid thermal decomposition of the binder in the compound. Then, after reaching a certain temperature, the calcined body 3 is obtained by maintaining the temperature for 30 minutes in a vacuum atmosphere.
(4) Coating process The outer surface of the calcined body 3 can be coated with the coating material 5 by coating the outer surface of the calcined body 3 with a coating material 5 which is, for example, a slurry-like insulating material.

  Below, the effect by embodiment of this invention is demonstrated.

  (1) The manufacturing method of the heater for heat treatment according to the present embodiment includes a step of producing a slurry composed of a mixture of these by dispersing silicon carbide powder in a solvent, and a green obtained by molding and drying the slurry. And calcining the body to prepare the calcined body 3, and covering the outer surface of the calcined body 3 with a covering material 5 which is an insulating material. Accordingly, by covering the porous calcined body 3 having a low rigidity with the coating material 5 made of an insulating material, a heat treatment heater with high durability and radiation efficiency, a simple manufacturing process and a low cost can be obtained. .

  (2) Since the covering material 5 is made of silica having a high light transmittance, the heat treatment heater 1 having a high radiation rate can be obtained.

[Fifth Embodiment]
Next, a method for manufacturing a heat treatment heater according to a fourth embodiment of the present invention will be described. However, the same components as those in the first to fourth embodiments described above are denoted by the same reference numerals and description thereof is omitted.

  In this embodiment, a quartz glass plate is joined to the heat treatment heater according to the fourth embodiment.

  That is, in 4th Embodiment, although the outer surface of the calcined body 3 was coat | covered with the coating | covering material 5 which is an insulating material, as shown in FIG. A step of joining the quartz glass plate 7 is added. The quartz glass plate 7 can be applied to any glass other than quartz glass that has heat resistance and transparency during heat treatment.

  Below, the effect by embodiment of this invention is demonstrated.

  (1) Since the quartz glass plate 7 having a high light transmittance is joined to the silicon carbide calcined body 3, the durability is further improved while maintaining a high radiation rate.

  It should not be understood that the description and the drawings, which form part of the disclosure of the above-described embodiments, limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the said 3rd Embodiment, although the circumference | surroundings of the calcined body 3 were coat | covered with the fusion agent 10, you may coat | cover with a quartz glass plate.

  Next, the present invention will be described more specifically through examples.

  FIG. 5 is a graph showing the relationship between the time during which a current is passed through each heater and the resistance increase rate in the example.

  In FIG. 5, a solid line A indicates a heater according to the present invention, a one-dot chain line B indicates a heater in which Si is infiltrated into a conventional calcined body, and a silica coating is applied. The heater impregnated with is shown. As shown in the graph of FIG. 5, it has been found that the heater according to the example of the present invention indicated by the solid line A has a small increase in resistance after the longest time.

  FIG. 6 is a graph showing the relationship between the current flowing time through the heater of Comparative Example 1 and the resistance increase rate in the embodiment, and FIG. 7 is the relationship between the current flowing time through the heater of Comparative Example 2 in the embodiment and the resistance increase rate. FIG. 8 is a graph showing the relationship between the time during which a current is passed through the heater according to the present invention and the resistance increase rate in Examples.

  Also from these graphs, it was found that, even after the heater according to the example of the present invention had passed for a long time, the resistance value showed an increasing tendency, but the resistivity change was small.

  FIG. 9 is a graph showing a change in emissivity due to surface roughness for the heater covering material in the example.

  X indicated by a thick solid line has an Ra of 1.5, Y indicated by an alternate long and short dash line has an Ra of 1.0, Z indicated by a dotted line has an Ra of 0.2, and W indicated by a thin solid line has an Ra of 0 0.025. As shown in this graph, it has been found that the emissivity increases as the surface roughness increases.

  FIG. 10 is a graph showing the temperature dependence of the volume resistance of the heater in the example. As shown in this graph, it has been found that the volume resistivity decreases as the temperature increases.

1,11,21 Heater for heat treatment 3 Calcined body 5 Coating material 7, 9 Quartz glass plate

Claims (6)

A calcined body obtained by calcining a porous body of silicon carbide;
A heat treatment heater comprising: a covering material made of an insulating material covering an outer surface of the calcined body.   The heater for heat treatment according to claim 1, wherein the covering material is made of silica.   The heater for heat treatment according to claim 1 or 2, wherein a quartz glass plate is joined to the calcined body. Producing a slurry comprising a mixture containing the silicon carbide powder by dispersing the silicon carbide powder in a solvent;
Forming the slurry and calcining the dried green body to produce a calcined body;
And a step of coating the outer surface of the calcined body with a coating material that is an insulating material.   The said coating | covering material consists of silica, The manufacturing method of the heater for heat processing of Claim 4 characterized by the above-mentioned.   6. The method for manufacturing a heat treatment heater according to claim 4, wherein after the calcined body is coated with an insulating material, a quartz glass plate is joined to the calcined body.

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