JP4148487B2 - Quartz glass heat insulating member and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a quartz glass heat insulating member mainly used in a semiconductor heat treatment apparatus and a method for manufacturing the same, and more specifically, a lid for closing an end of a core tube of a heat treatment furnace, heat attached to the front and rear of a wafer boat. The present invention relates to a quartz glass heat insulating member used as a shield, a wafer boat mounting table or the like inserted in a furnace core tube of a vertical heat treatment furnace, and a manufacturing method thereof.
[0002]
[Prior art]
Conventionally, as this type of quartz glass heat insulating member, a hollow outer shell made of quartz glass is filled with quartz glass wool and vacuum-sealed, or the surface of an amorphous quartz glass foam made of vacuum closed cells Is covered with a quartz glass layer (see JP-A-6-252074).
The former quartz glass heat insulating member is manufactured by filling a hollow outer shell made of quartz glass with quartz glass wool from its opening, exhausting the inside of the outer shell, and then sealing the opening. The latter quartz glass heat insulating member is filled with quartz glass powder in a carbon crucible of the required shape and heat-treated under reduced pressure to melt and foam the quartz glass powder to obtain a quartz glass foam, which is prepared in advance. It is manufactured by enclosing it in an outer shell made of quartz glass or by heating and melting the surface of the foam with an oxyhydrogen gas burner.
[0003]
[Problems to be solved by the invention]
However, in the former quartz glass heat insulating member, the quartz glass wool has a relatively low heat resistance of 300 to 400 ° C., and when exposed to such a relatively low temperature for a long time, the strength decreases, and it is used or carried. There is a problem in that the fibers constituting the wool are gradually broken and powdered by a slight impact, and the heat insulation performance is significantly lowered.
Further, at a temperature of 1000 ° C. or higher, since the fibers begin to sinter and the volume shrinks, the scattering ability of infrared radiation (heat rays) is lowered, and the heat insulation performance is remarkably lowered.
On the other hand, it is extremely difficult to uniformly fill the outer shell with quartz glass wool during its manufacture, and the wool has a very large specific surface area, so there is a large amount of adsorbed gas, and the vacuum inside the outer shell is necessary. In addition to taking a long time to reduce the temperature, there is a problem that during decompression, the wool is sucked into the suction port and a large gap is formed in the outer shell.
[0004]
In the latter quartz glass heat insulating member, the pressure of the residual gas in the closed cells heated to near the softening temperature (1200 ° C.) of the quartz glass is more than five times the value at room temperature, but once manufactured. Since the gas in the closed cells cannot be removed later, the pressure of the residual gas is 1/5 atm or higher, or when the pressure at the time of heating is 1 atm or higher due to separation of the adsorbed gas during heating, There is a problem that the expansion of the closed cell causes a change in dimensions or damage to the device.
On the other hand, in the case of the method of encapsulating quartz glass foam in the outer shell, the foam must be processed in accordance with the shape of the outer shell. In addition, when the surface of the foam is heated and melted, closed cells expand and rupture during the heating process, so that it is difficult to form a dense layer with a sufficient thickness and it is difficult to obtain a smooth surface shape. Airtightness and dimensional accuracy are also insufficient.
Then, an object of this invention is to provide the manufacturing method of the quartz glass heat insulation member which can be easily manufactured and the quartz glass heat insulation member which exhibits a uniform and high heat insulation over a long period of time.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the first quartz glass heat insulating member of the present invention is characterized in that a hollow outer shell made of quartz glass is filled with a granular porous silica and vacuum-sealed.
In the first quartz glass heat insulating member, the granular silica porous bodies are fused to each other, or the granular silica porous bodies are fused to each other and fused to the outer shell. And
[0006]
On the other hand, according to the first method for producing a quartz glass heat insulating member of the present invention, a hollow outer shell made of quartz glass is filled with a granular silica porous body from its opening, and the inside of the outer shell is evacuated and then opened. The portion is sealed.
The second method for manufacturing a quartz glass heat insulating member is the first method, wherein heating is performed at a temperature of 1300 to 1450 ° C. before, in parallel with, or after evacuating the outer shell. It is characterized by.
[0007]
The granular porous silica preferably has a particle size of 0.5 to 5 mm.
The granular silica porous body preferably has a porosity of 15 to 60%.
It is preferable that the granular silica porous body is formed by sintering silica particles.
Further, the granular silica porous body is obtained by granulating a silica powder by adding an aqueous solution of a basic quaternary ammonium compound, and firing the granulated body at a temperature of 1300 to 1450 ° C. Is preferred.
The aqueous solution of the basic quaternary ammonium compound is preferably added at an external rate of 5 to 25 wt% with respect to the silica powder at a concentration of 0.01 to 5%.
On the other hand, the aqueous solution preferably contains a silica component.
The silica content is preferably 0.1 to 5 wt% of the aqueous solution.
[0008]
The degree of vacuum in the outer shell is desirably 5 Torr or less. If it exceeds 5 Torr, the effect of removing convective heat transfer is reduced.
[0009]
When the temperature of the heating performed in parallel with or after evacuation before the evacuation in the outer shell is less than 1300 ° C., the fusion between the granular silica porous bodies, or between the granular silica porous bodies When the temperature exceeds 1450 ° C., deformation of the granular silica porous body and / or outer shell occurs. A desirable heating temperature is 1350 to 1450 ° C. Heating is preferably performed in parallel with evacuation.
[0010]
By making the particle diameter of the granular silica porous body 0.5 to 5 mm, the fluidity becomes good, the outer shell can be filled uniformly without any gap, and the heat insulation becomes uniform. Moreover, evacuation can be performed in a shorter time.
When the granular silica porous body has a particle size of less than 0.5 mm, it is discharged from the opening by vacuum suction during production. On the other hand, when the particle size exceeds 5 mm, the gap between the particles becomes large and the heat insulating property is increased. There is a risk of lowering. The particle size is preferably 1 to 5 mm, more preferably 3 to 5 mm.
[0011]
The granular porous silica preferably has a porosity of 15 to 60%.
When the porosity is less than 15%, the heat insulating action of the porous silica material is reduced, so that the heat insulating property as the heat insulating member is lowered and it is difficult to evacuate in manufacturing. On the other hand, if it exceeds 60%, the mechanical strength of the porous silica material is reduced, so that it is broken and becomes a powder, which causes a decrease in heat insulating properties and causes problems such as dusting during production. A more desirable porosity is 30 to 50%.
[0012]
The granular porous silica preferably has an average pore size of 0.5 to 30 μm.
When the average pore diameter is less than 0.5 μm, the heat insulating action of the porous silica material is reduced, so that the heat insulating property as a heat insulating member is lowered and evacuation becomes difficult at the time of production. On the other hand, when the thickness exceeds 30 μm, the mechanical strength of the porous silica material is reduced, so that the silica porous material is broken and becomes a powder, which causes a decrease in heat insulating properties and causes problems such as dust generation during production. More desirably, the average pore diameter is 1.5 to 20 μm.
[0013]
Since the granular silica porous body is formed by sintering silica particles, the heat resistance at the sintering temperature is stable, and the heat insulating property does not deteriorate even when exposed to the temperature.
[0014]
When a mixture of silica powder and an aqueous solution of a basic quaternary ammonium compound dissolves the surface layer of the silica powder particles during granulation, the granulation is dried (at a temperature of about room temperature to 130 ° C.). The dissolved silica content precipitates on the surface of the silica powder particles and joins the particles together. That is, when the granule is heated, the aqueous solution of the basic quaternary ammonium compound is at most 200 ° C. While it decomposes and volatilizes without leaving any residue at the temperature, the silica precipitates exist stably until sintering, and the silica powder particles are bonded to each other. In addition, since the silica precipitate is active, it is sintered prior to deformation due to viscous flow of the powder particles serving as a skeleton, thereby forming a dense silica layer between the particles.
Therefore, the shape-retaining property of the granulated body is good and deformation during sintering is reduced, so that the shape can be controlled and the pore diameter, pore distribution, and porosity can be easily controlled. In addition, the sintered body can obtain sufficient mechanical strength.
[0015]
It is desirable that the silica powder has an appropriate particle size and particle size distribution. By doing so, the pore diameter and pore distribution of the granular silica porous body can be controlled. As the particle size is set larger, the pore size can be increased, and the particle size distribution is narrowed (the particle size is made uniform), thereby narrowing the pore distribution of the granular silica porous material (the pore size is made uniform). Can). Conversely, the use of raw material powders of various particle sizes widens the pore distribution.
The characteristics of the pores are further improved when spherical silica powder is used, but the object can be sufficiently achieved even with a pulverized product.
In order to make the particle size and particle size distribution of the silica powder uniform, the raw material powder is classified by a method such as sieving, sedimentation, or cyclone classification.
The silica porous body preferably has a total sum of sodium and potassium of 5 ppm or less, a sum of calcium and magnesium of 2 ppm or less, and a total of iron, chromium, nickel and copper of 1 ppm or less. When these contents are exceeded, the heat resistance is lowered, and it becomes impossible to apply to applications requiring particularly high purity.
[0016]
When the aqueous solution of the basic quaternary ammonium compound has a concentration of less than 0.01%, the dissolved amount of silica that functions as a binder is insufficient. On the other hand, if the concentration exceeds 5%, the dissolution of silica proceeds more than necessary, and the solution becomes difficult to handle.
Granulation becomes difficult when the addition amount of the aqueous solution of the basic quaternary ammonium compound is less than 5 wt% in terms of the external ratio with respect to the silica powder. On the other hand, when it exceeds 25 wt%, there is a problem that moisture exudes from the granulated body.
As the quaternary ammonium compound, tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline, acetylcholine, tetrabutylammonium hydroxide, phenyltrimethylammonium hydroxide, etc. are used. Among them, choline and its derivatives are moldable. Has advantages such as being good and easy to handle.
[0017]
The granulation is preferably the vibration granulation method. For example, in order to prevent contamination by metal impurities, vibration granulation uses a flat-bottomed container made of plastic, ceramics, etc., and the silica powder accommodated in the container is given a motion such as rocking and rotating. An aqueous solution of a basic quaternary ammonium compound is added by means such as spraying, and the movement is continued to agglomerate into granules.
[0018]
If the firing temperature of the granulated body is less than 1300 ° C., sufficient strength cannot be obtained. On the other hand, when the temperature exceeds 1450 ° C., the flow and deformation of the silica particles proceed excessively, and the outer shape and pore distribution cannot be controlled.
Even when silica powder having the same particle size is used, the porosity of the porous body can be controlled by adjusting the firing temperature condition within the above range. As the firing temperature is increased, the porosity can be reduced. Also, the smaller the porosity, the higher the strength. Therefore, it can be said that the mechanical strength of the granulated body mainly depends on the firing temperature.
Prior to firing, the granulated body is left in the room or dried by raising the temperature to around 100 ° C., and then the granulated body is fired and sintered using an electric furnace or the like.
The firing atmosphere is not particularly selected, but is usually performed in an oxidizing atmosphere such as air.
At the stage of drying or firing the granulated body, a clean device or jig is used to prevent the granulated body from being contaminated.
[0019]
When a silica component such as silica powder or soluble silica compound is added to an aqueous solution of a basic quaternary ammonium compound, the strength of the granulated body and sintered body is further improved.
If the silica content is less than 0.1 wt% of the aqueous solution of the basic quaternary ammonium compound, the effect does not appear. On the other hand, if the silica content exceeds 5 wt%, the viscosity of the solution increases and the moldability is hindered.
[0020]
The outer shell may be transparent quartz glass or porous opaque quartz glass. However, in the case of using porous quartz glass, the outer surface is closed by pores by heating and melting the outer surface, and the outside and the inside are not vented.
The purity may be appropriately selected depending on the use environment, and is generally preferably 99% or more.
Further, the shape may be hollow so as to fill the inside with a granular silica porous body, and is usually a hollow plate shape having a circular or square cross-sectional shape. In addition, airtightness is necessary so that vacuum sealing is possible.
Further, the wall thickness is not particularly limited as long as it can be processed such as welding and has sufficient strength to be used as a heat insulating member, but is preferably 1 mm or more from the viewpoint of heat insulating properties.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a sectional view showing a first embodiment of a quartz glass heat insulating member according to the present invention.
As shown in FIG. 2, the quartz glass heat insulating member 1 serves as a lid that hermetically closes both ends of the quartz glass furnace core tube 2 in a horizontal heat treatment furnace (not shown), and is a high-purity quartz. An outer shell 3 made of glass and having a hollow cone shape that can be fitted to the end of the quartz glass furnace core tube 2 is provided. A gas pipe 4 made of the same quartz glass and used for introducing or discharging gas is hermetically inserted.
The outer shell 3 is filled with a high-purity granular porous silica 5 having a particle size of 0.5 to 5 mm, a porosity of 15 to 60%, and an average pore size of 0.5 to 30 μm, and 5 Torr or less. It is sealed with a vacuum.
[0022]
The granular silica porous body 5 has an external ratio of 5 to 0.01% by weight of an aqueous solution of a basic quaternary ammonium compound in a concentration of 0.01 to 5% or a silica content of 0.1 to 5 wt%. After adding ~ 25 wt%, granulating by vibration and drying the granulated body, it is fired at a temperature of 1300 to 1450 ° C in the air.
The obtained porous body 5 had a total of Na and K of 5 ppm or less, a total of Ca and Mg of 2 ppm or less, and a total of Fe, Ni, Cr and Cu of 1 ppm or less.
[0023]
In order to manufacture the quartz glass heat insulating member 1 described above, first, as shown in FIG. 3, the outer shell 3 having the gas pipe 4 inserted and provided with the opening 6 is manufactured (first step), Next, as shown in FIG. 4, the granular silica porous body 5 was charged and filled from the opening 6 (second step).
Next, as shown in FIG. 5, a suction pipe 7 of a vacuum pump (not shown) is connected to the opening 6 and evacuated, and then the opening 6 is sealed with an oxyhydrogen gas burner 8 (third step). Thereafter, as shown in FIG. 6, the sealing portion 3a was finished with the oxyhydrogen gas burner 8 to obtain the quartz glass heat insulating member 1 (fourth step).
In order to facilitate the separation of the adsorbed gas during vacuum evacuation, it is preferable to perform so-called baking in which the whole is heated (usually about 300 to 400 ° C.).
[0024]
In the quartz glass heat insulating member 1 having the above configuration, the granular silica porous body has high heat resistance, heat ray scattering characteristics, and low thermal conductivity. Therefore, the effect of removing convective heat transfer by vacuum sealing is also considered. Thus, it is possible to exhibit a uniform and high heat insulating property over a long period of time.
In addition, since the porous silica 5 is sintered at a high temperature of 1300 to 1450 ° C. and the heat resistance at that temperature is stable, the heat insulating property may deteriorate even when exposed to a high temperature. Absent.
On the other hand, since the granular silica porous body 5 is light and rich in fluidity in the production thereof, the outer shell 3 having any shape can be uniformly filled without a gap, and a heat insulating member having a uniform heat insulating property can be obtained. It can be produced very easily.
[0025]
FIG. 7 is a cross-sectional view showing a second embodiment of the quartz glass heat insulating member according to the present invention.
This quartz glass heat insulating member 9 is used as a part of a wafer boat mounting table loaded in a quartz glass furnace core tube (both not shown) in a vertical heat treatment furnace, and is made of high-purity quartz glass. In the outer shell 10 having a hollow (wall thickness: 1.5 to 2 mm) disk shape having a diameter of 30 mm and a height of 24 mm, the average particle diameter is 1.5 mm, the average pore diameter is 5 μm, and the porosity is 45%. A granular porous silica 11 having the same purity obtained in the same manner as in the first embodiment is filled and vacuum-sealed at a pressure of 0.003 Torr.
[0026]
In order to manufacture the quartz glass heat insulating member 9 described above, first, although not shown in the drawing, the outer periphery of a short cylindrical body made of high-purity quartz glass having an outer diameter of 30 mm, an inner diameter of 27 mm, and a height of 20 mm is similarly applied. After forming a tubular opening with an outer diameter of 10 mm and an inner diameter of 8 mm, it is made of high-purity quartz glass, and is made of high-purity quartz glass at both ends of the short cylindrical body. The outer shell 10 was manufactured by hermetically welding.
Next, the granular silica porous body 11 is filled into the outer shell 10 from the opening, and the whole is baked at a temperature of 300 ° C. or higher and evacuated from the opening to a pressure of 0.003 Torr. Then, the opening was sealed and finished to a sealing portion 10a to obtain a quartz glass heat insulating member 9.
The time required for evacuation (time required to achieve 0.003 Torr) was 5 minutes.
[0027]
On the other hand, in order to compare with the said quartz glass heat insulation member 9, the conventional quartz glass heat insulation member 12 shown in FIG. 8 was manufactured.
This quartz glass heat insulating member 12 is used as a part of the wafer boat mounting table in the same manner as in the second embodiment, and is made of high-purity quartz glass and is a hollow (diameter 30 mm, height 24 mm) The outer shell 13 having a disk shape with a wall thickness of 1.5 to 2 mm is almost filled with quartz glass wool having a diameter of 25 μm and a length of 5 to 30 mm, and is vacuum-sealed at a pressure of 0.1 Torr. is there.
[0028]
In order to manufacture the above-described quartz glass heat insulating member 12, first, although not shown in the drawing, the outer periphery of a short cylindrical body made of high purity quartz glass having an outer diameter of 30 mm, an inner diameter of 27 mm, and a height of 20 mm is similarly applied. After forming a tubular opening made of high-purity quartz glass with an outer diameter of 10 mm and an inner diameter of 8 mm, a disc made of high-purity quartz glass made of high-purity quartz glass with a diameter of 30 mm and a thickness of 2 mm is hermetically sealed at one end of the short cylindrical body. Welded.
Next, after filling the quartz glass wool 14 with the other end of the short cylinder facing upward, a disk made of high purity quartz glass and having a diameter of 30 mm and a thickness of 2 mm will be welded to the other end of the short cylinder. As a result, the quartz glass wool 14 near the welded portion melted and adhered during welding, and it was difficult to achieve airtight sealing.
Therefore, the packing density of the quartz glass wool 14 was lowered, a gap was provided between the welded portions, and the disk was hermetically welded to the other end of the short cylindrical body to produce the outer shell 13 containing the quartz glass wool 14. .
Next, when the pressure was evacuated from the opening and the pressure became 0.1 Torr, the opening was sealed, and finished into a sealing portion 13a to obtain the quartz glass heat insulating member 12.
The time required for evacuation (time required to achieve 0.1 Torr) was 30 minutes.
[0029]
In order to compare the performance of the above-mentioned two types of quartz glass heat insulating members 9 and 12, the light transmitted through the He-Ne laser beam while being irradiated in parallel with the height direction of the outer shells 10 and 13 from one surface. The in-plane distribution of the strength of the quartz glass insulator 9 according to the present invention showed a variation of 5% or less within the range of the effective surface (the surface excluding the thickness of the side wall of the short cylindrical body). On the other hand, the conventional quartz glass heat insulating member 12 had a variation of 30% or more.
Also, after both were heated for 10 hours at a temperature of 1300 ° C., changes in performance and appearance were examined. Whereas the quartz glass member 9 according to the present invention was not changed at all, conventional quartz glass insulation The member 12 was fused to a part of the quartz glass wool 14 and the heat insulating performance was lowered.
[0030]
FIG. 9 is a sectional view showing a third embodiment of a quartz glass heat insulating member according to the present invention.
This quartz glass heat insulating member 15 is used as a heat shield attached to the front and rear of a horizontal wafer boat (not shown), is made of high purity quartz glass, and is hollow (thickness) with a diameter of 30 mm and a height of 14 mm. In the outer shell 16 having a disk shape of 2 mm), the average particle diameter is 3 mm, the average pore diameter is 5 μm, and the porosity is 45%, which is the same as that obtained in the same manner as in the first embodiment. It is filled with a granular porous silica 17 and vacuum-sealed at a pressure of 0.1 Torr.
[0031]
In order to manufacture the quartz glass heat insulating member 15 described above, first, although not shown in the drawing, it is similarly formed on the outer peripheral portion of a short cylindrical body made of high-purity quartz glass having an outer diameter of 30 mm, an inner diameter of 26 mm, and a height of 10 mm. After forming a tubular opening with an outer diameter of 10 mm and an inner diameter of 8 mm made of high purity quartz glass, two circles made of high purity quartz glass with a diameter of 30 mm and a thickness of 2 mm are formed at both ends of the short cylindrical body. The plate was air-tightly welded to produce the outer shell 16.
Next, the porous silica 17 is filled into the outer shell 16 from the opening, and the opening is sealed when the pressure is 0.1 Torr when the opening is evacuated and the sealing portion 16a is sealed. The quartz glass member 15 was obtained.
[0032]
On the other hand, for comparison with the quartz glass heat insulating member 15, as shown in FIG. 10, a three-plate disk 18 made of high-purity quartz glass, having a diameter of 30 mm, a thickness of 2 mm, and double-sided sand printing is similarly used. A conventional quartz glass heat insulating member 20 that is welded and fixed at an equal interval of 2 mm through a plurality of spacers 19 made of high purity quartz glass and used as a heat shield attached to the front and rear of a horizontal wafer boat (not shown). Manufactured.
[0033]
In order to compare the performance of the two types of quartz glass heat insulating members 15 and 20, the transmittance of radiation at a temperature of 1000 ° C. was measured, whereas the quartz glass heat insulating member 15 according to the present invention was 30%. The conventional quartz glass heat insulating member 20 was 70%, and the heat insulating property was greatly inferior.
In the measurement, quartz glass heat insulating members 15 and 20 are installed between two radiation plates, heated to a temperature of 1000 ° C. in a vacuum atmosphere of 0.1 Torr, a heat pulse is applied to one radiation plate, quartz quartz According to the method of measuring the degree to which the other radiation plate is heated by the radiation that has passed through the glass heat insulating members 15 and 20.
In addition, even if the quartz glass heat insulation member 15 which concerns on this invention was heated to the temperature of 1300 degreeC, the performance and the external appearance did not change.
[0034]
In each of the above-described embodiments, the case where the granular silica porous bodies 5, 11, 17 and the granular silica porous bodies 5, 11, 17 and the outer shells 3, 10, 16 are separated from each other has been described. However, the present invention is not limited to this, and the outer shells 3, 10, 16 and the granular silica filled in the outer shells 3, 10, 16 are filled before or after the vacuum evacuation. By heating the porous bodies 5, 11, and 17 at a temperature of 1300 to 1450 ° C., the granular silica porous bodies 5, 11, and 17 are fused to each other, or the granular silica porous bodies 5, 11, and 17 are fused to each other. At the same time, it may be fused to the outer shells 3, 10, 16.
By doing in this way, the granular silica porous bodies 5, 11, and 17 are not moved and worn by mechanical shock from the outside, and the heat insulating performance can be maintained for a long period of time.
Further, in the production thereof, the particulate silica porous bodies 5, 11, and 17 are not discharged to the outside by suction by a vacuum pump.
[0035]
【The invention's effect】
As described above, according to the first quartz glass heat insulating member and the method for producing the same of the present invention, the granular silica porous body has high heat resistance, heat ray scattering characteristics, and low thermal conductivity. Combined with the effect of removing convective heat transfer by vacuum encapsulation, it is possible to exhibit uniform and high heat insulation over a long period of time.
On the other hand, since the porous silica is light and rich in fluidity, it can be uniformly filled without any gaps in the outer shell of any shape, and a heat insulating member having uniform heat insulating properties can be manufactured very easily. it can.
[0036]
Further, according to the second quartz glass heat insulating member and the manufacturing method thereof, in addition to the first and the effects obtained by the method, the granular silica porous body or the granular silica porous body and the outer shell are integrated. Therefore, the granular porous silica is not moved and worn by mechanical shock from the outside, and the heat insulation performance can be maintained for a long period of time.
On the other hand, since the porous silica is not discharged to the outside during vacuum suction, the production can be easily performed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of a quartz glass heat insulating member according to the present invention.
2 is a cross-sectional view of a quartz glass furnace core tube using the quartz glass heat insulating member of FIG. 1. FIG.
3 is a cross-sectional view showing a first step of the method for producing the quartz glass heat insulating member of FIG. 1. FIG.
4 is a cross-sectional view showing a second step of the method for manufacturing the quartz glass heat insulating member of FIG. 1. FIG.
5 is a cross-sectional view showing a third step of the method for manufacturing the quartz glass heat insulating member of FIG. 1. FIG.
6 is a cross-sectional view showing a fourth step of the method for manufacturing the quartz glass heat insulating member of FIG. 1. FIG.
FIG. 7 is a cross-sectional view showing a second embodiment of a quartz glass heat insulating member according to the present invention.
FIG. 8 is a cross-sectional view of a conventional quartz glass heat insulating member.
FIG. 9 is a cross-sectional view showing a third embodiment of a quartz glass heat insulating member according to the present invention.
FIG. 10 is a cross-sectional view of another conventional quartz glass heat insulating member.
[Explanation of symbols]
3 outer shell 3a sealing part 5 silica porous body 6 opening 10 outer shell 10a sealing part 11 silica porous body 16 outer shell 16a sealing part 17 silica porous body

Claims (16)

A quartz glass heat insulating member characterized in that a hollow porous shell made of quartz glass is filled with a granular silica porous body and vacuum-sealed. 2. The quartz glass heat insulating member according to claim 1, wherein the granular silica porous bodies are fused together, or the granular silica porous bodies are fused together and fused to the outer shell. The quartz glass heat insulating member according to claim 1 or 2, wherein the granular silica porous body has a particle diameter of 0.5 to 5 mm. The quartz glass heat insulating member according to claim 1, wherein the granular silica porous body has a porosity of 15 to 60%. The quartz glass heat insulating member according to claim 1, wherein the granular silica porous body is formed by sintering silica particles. The granular silica porous body is obtained by granulating a silica powder by adding an aqueous solution of a basic quaternary ammonium compound, and firing the granulated body at a temperature of 1300 to 1450 ° C. The quartz glass heat insulating member according to claim 1, 2, 3, 4, or 5. The quartz glass according to claim 6, wherein the aqueous solution of the basic quaternary ammonium compound is added at an external rate of 5 to 25 wt% with respect to the silica powder at a concentration of 0.01 to 5%. Thermal insulation member. The quartz glass heat insulating member according to claim 6 or 7, wherein the aqueous solution contains a silica component. A method for producing a quartz glass heat insulating member comprising filling a hollow silica shell made of silica glass with a granular porous silica from its opening, evacuating the outer shell, and then sealing the opening . The method for manufacturing a quartz glass heat insulating member according to claim 9, wherein heating is performed at a temperature of 1300 to 1450 ° C. in parallel with or after evacuation before evacuation of the outer shell. The method for producing a quartz glass heat insulating member according to claim 9 or 10, wherein the granular silica porous body has a particle diameter of 0.5 to 5 mm. The method for producing a quartz glass heat insulating member according to claim 9, 10 or 11, wherein the granular silica porous body has a porosity of 15 to 60%. 13. The method for producing a quartz glass heat insulating member according to claim 9, wherein the granular silica porous body is obtained by sintering silica particles. The granular silica porous body is obtained by granulating a silica powder by adding an aqueous solution of a basic quaternary ammonium compound, and firing the granulated body at a temperature of 1300 to 1450 ° C. The method for producing a quartz glass heat insulating member according to claim 9, 10, 11, 12, or 13. The quartz glass according to claim 14, wherein the aqueous solution of the basic quaternary ammonium compound is added in an external ratio of 5 to 25 wt% with respect to the silica powder at a concentration of 0.01 to 5%. Manufacturing method of heat insulation member. The method for producing a quartz glass heat insulating member according to claim 14 or 15, wherein the aqueous solution contains a silica component.

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