JP3843139B2 - Manufacturing method and apparatus for large round sealed quartz glass tube - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a glass tube having a round end sealed, and more particularly, to a method for manufacturing a large round sealed quartz glass tube used for semiconductor manufacturing or the like and an apparatus therefor.
[0002]
[Prior art]
Conventionally, as a method of manufacturing a glass tube having a round sealed portion, as shown in FIG. 7, a glass tube processed into a predetermined size diameter is attached to a processing jig, and the round sealed portion of the glass tube is heated while rotating. In the plastic region of the glass, the round portion was formed by sealing from the peripheral portion.
[0003]
Moreover, in order to make the shape of a round seal part accurate, the shaping | molding method which blows and expands in the mold | die made from graphite as shown in FIG. 8 is also used.
[0004]
[Problems to be solved by the invention]
However, in the conventional method of forming a round portion by heating a round-sealed portion and squeezing from the peripheral portion, a material having a high viscosity such as quartz glass must be heated to a considerably high temperature to make the glass a plastic region. In addition, when used as a material for semiconductor manufacturing, the wafer diameter itself has become larger with the recent high degree of integration, and the material itself has also become larger. It was.
[0005]
For example, a quartz glass jig for vertical semiconductor heat treatment requires a furnace core tube having a large diameter of 200φ or more, so that a round seal portion corresponding to the square of the diameter is required to form a round seal portion corresponding to the required shape. It requires an area, and it takes a considerable heat energy source and a great amount of processing effort to seal it while gradually reducing its diameter.
[0006]
In addition, the glass tube is sealed by rotating the glass tube with a glass lathe or the like and using the centrifugal force to heat the flame with a burner. The balance of heat energy supplied by the burner at the periphery and the center of the tube tends to be non-uniform, and a difference in viscosity occurs on the inner and outer circumferences of the round seal, resulting in a non-uniform thickness near the center of the tube. For this reason, there has been a problem that a significant reduction in strength is caused in the thinned portion.
[0007]
In addition, since the center part is melted and sealed, the so-called navel portion remains, and the round seal surface around the navel portion becomes circular and uneven along the rotation axis due to the rotation of the tube, making it difficult to obtain a smooth surface. Therefore, it becomes difficult to stably produce a round sealed surface shape having a predetermined curvature with good reproducibility.
[0008]
In addition, the molding method that blows and expands into a graphite mold requires secondary energy costs and labor, is not productive, and has a high risk of impairing purity due to contact with a contamination source. There was a problem in using the product as a manufacturing material for semiconductors for which products are required.
[0009]
Thus, in the conventional method, enormous labor and energy are required to obtain a large-sized round sealed quartz glass tube as a recent semiconductor manufacturing material, and a high-purity product for semiconductors can be obtained. However, it has been demanded to provide a large-sized round sealed quartz glass tube with improved workability, good reproducibility and high accuracy.
[0010]
The present invention produces a large round sealed quartz glass tube having a predetermined curvature with high precision and smoothness, with high productivity and reproducibility in an integrated continuous operation without requiring a high degree of skill. An object of the present invention is to provide a large round quartz glass tube excellent in strength and dimensionality as a semiconductor manufacturing jig.
[0011]
[Means for Solving the Problems]
Therefore, as a result of intensive research in order to solve the above problems, the present inventor fused the quartz glass tube end face and the quartz glass disk so as to face each other with their centers aligned and welded by a high temperature flame. Thereafter, the sealed surface is heated with a high-temperature flame while rotating the integrated object, and the gas pressure inserted from the other end of the quartz glass tube is adjusted so that the sealed surface has a predetermined curvature. As a result, the present invention was completed with the knowledge that a large round-sealed quartz glass tube with high reproducibility and high accuracy can be manufactured by continuous simple work.
[0012]
In addition, the large round sealed quartz glass tube manufacturing apparatus includes a rotation support means for supporting the quartz glass tube while rotating the quartz glass tube around its long axis, and the quartz glass tube end face and the quartz glass disk or A local heating means for heating and softening the welded integrated article, a pressure applying means for applying a gas pressure in the welded integrated article, and a round for forming a round sealed surface of the welded integrated article into a curved portion having a predetermined curvature. It is provided with sealing shape regulating means.
[0013]
[Action]
The quartz glass tube and quartz glass disk are welded to each other using a normal glass lathe with support means that can be rotated on both sides, so that the rotational axis is aligned and no misalignment occurs during welding. Opposing to the.
[0014]
Quartz glass discs are arranged to face each other with the same diameter and thickness as the outer diameter of the quartz glass tube end face (Fig. 2), or slightly smaller than the quartz glass tube inner diameter.・ Insert into a glass tube with approximately the same thickness (FIG. 3), and weld them together with a high temperature flame. As a result, it is possible to suppress the wall thickness variation during the formation of the curved portion of the round-sealed portion due to the difference in heat conduction and to maintain the heat balance. In addition, the thickness of the quartz glass disk forming the round seal part is appropriately adjusted in principle with the same thickness in principle from the relationship between the curvature of the round seal part surface and the specified thickness.
[0015]
It is possible to expand the weld end surface of the quartz glass tube on which the quartz glass disk has been welded in a taper shape from the glass tube diameter, heat the enlarged portion and the welded integral, and bulge outward by an internal pressure load. This is effective in preventing the welded surface from shifting toward the center of the sealed portion during round sealing, and maintaining a uniform viscous plastic region to suppress fluctuations in the thickness of the entire round sealed surface (see FIG. 4).
[0016]
If the diameter is not expanded into a taper shape, the welding surface will be displaced toward the center of the round seal due to heating and internal pressure during the creation of the round seal, and the curvature of the corner corresponding to the boundary between the outer diameter straight portion and the round seal surface of the quartz glass tube It tends to be smaller than the predetermined curvature, and the distance between the vertices of the tube straight portion and the round seal portion is measured to detect the predetermined curvature and cause an error in feeding back. This is because the larger the shape and the smaller the predetermined radius of curvature of the round sealing surface, the stronger this tendency. Therefore, especially when forming a large-sized product or a round sealing portion with a small curvature, the taper-shaped diameter increases. It becomes effective.
[0017]
The diameter-expansion to the taper shape is obtained by heating the diameter-expanded portion and applying an internal pressure, but a glass tube whose end portion has been diameter-expanded in advance before disc welding may be used.
[0018]
The diameter of the quartz glass disk should be approximately the same as or slightly smaller than the outer diameter of the quartz glass tube end face. It is appropriately selected depending on the curvature.
[0019]
The heating means preferably uses one or a plurality of oxyhydrogen flame burners with an angle adjusting mechanism provided with a moving means, and supports the end face of the quartz glass tube and the quartz glass disk or the welded integrated body in a rotating manner. The quartz glass tube supported by the means is heated and softened while rotating.
[0020]
The other end of the welded integrated object is connected to a pressure applying means for applying a gas pressure in the welded integrated object, thereby adjusting the inside of the welded integrated object to an appropriate pressure.
[0021]
The round-sealed shape restricting means is a guide that is arranged opposite to the welded integrated object, moves on the rotation axis of the glass tube and is set to a predetermined curvature of the round-sealed surface (FIGS. 5 and 6), covers the guide from the vicinity of the center portion It consists of a heat shield for blocking the heat rays that move up and down.
[0022]
The guide is preferably made of a metal such as stainless steel so that it does not wear. The guide itself has a curvature that is generally required, and has the role of detecting and correcting the curvature of the sealed portion, as shown in FIG. The upper and lower parts can be divided into two parts.
[0023]
To detect the difference in curvature, measure the distance between the protruding vertices of the sealed surface without contact, calculate the difference in curvature based on the difference from the guide, and display it on the monitor. Adjusting and controlling the internal pressure and heating temperature so as to follow the curvature of the guide, the rounded sealing surface is set as the R portion having a predetermined curvature, but it is also possible to bring the guide having the desired curvature into contact with the predetermined curvature. it can. In addition, it is also possible to create a round-sealed portion without contact at first and press the guide against the round-sealed surface in the final stage after the R-section forming process to make final adjustments. It is effective in obtaining.
[0024]
As a heat shielding means, a flat plate, a curved surface, or a combination of these, a material having a heat ray shielding effect is used, and is made of quartz glass having high purity and heat resistance, which is a common material with a glass tube or the like. May be used. By arranging the heat shielding means opposite to the sealed object, it prevents wasteful consumption due to the diffusion of heat energy from the burner, and increases the viscosity at the center of the sealed surface, which causes insolubility of the center due to large products. It is possible to prevent and efficiently soak the entire surface, and to prevent deterioration of the guide made of metal or the like as the round-sealed shape regulating means.
[0025]
The apparatus of the present invention can be obtained by easily improving a conventional glass lathe apparatus.
[0026]
According to such technical means, the glass tube and the disk are welded and sealed, and then the disk part is bulged to form a round part. Therefore, the thickness of the disk to be the round part is arbitrarily selected. In addition, the diameter of the glass tube as in the prior art can be reduced to prevent thinning such as thinning during sealing. In addition, since it is only necessary to heat the glass tube and disk welded integral, the entire surface can be heated uniformly, and the inner and outer peripheral surface viscosity of the round sealed surface can be processed into a surface with a predetermined curvature under substantially the same conditions. The internal pressure load applied to the surface of the welded integrated object can be reduced, and the entire surface can be made uniform by reducing the wall thickness due to the bulge of the disk portion. This makes it possible to produce a large round quartz glass tube with very little wall thickness fluctuation at the round seal, and the round seal surface itself is conspicuous in the center of the tube. An excellent smooth surface that is smooth throughout can be obtained without remaining.
[0027]
【effect】
According to the present invention, as described above, a large round sealed quartz glass tube having a round curved surface formed with a smooth curved surface and having a predetermined curvature with high accuracy is like a glass lathe without requiring a high degree of skill. By improving such an ordinary apparatus, it is possible to manufacture with good productivity and reproducibility in an integrated continuous operation. Especially because the controllability such as the straight part length of the pipe outer diameter and the distance between the apexes of the round seal part is good, it is a large size excellent in strength and dimensionality as a jig for semiconductor manufacturing such as a double pipe for vertical semiconductor heat treatment A round sealed quartz glass tube can be provided.
[0028]
【Example】
Example 1
A large quartz glass tube having an outer diameter of 314 mm, an inner diameter of 305 mm, a thickness of 4.5 mm, and a length of 1500 mm was obtained from a quartz glass ingot by an ordinary pipe manufacturing method. The quartz glass tube is attached to the rotation support means at the left end of the glass lathe so as to rotate about the long axis of the tube, and the quartz glass disk having an outer diameter of 314 mm × wall thickness of 4.7 mm is attached to the rotation support means at the right end of the glass lathe Was placed so that the center of the disc coincided with the center of the opposing glass tube. Next, the right end rotation support means is moved, and both are temporarily welded with an oxyhydrogen flame burner, and further, the main pressure is increased with an oxyhydrogen flame burner, the internal pressure is increased, and the tip of the glass tube is heated to The diameter was increased in a tapered shape so that the outer diameter was 344 mm at 15 mm.
[0029]
Next, as shown in FIG. 6, a guide having a predetermined curvature surface that can move on the rotation axis of the glass tube, and a round seal that is divided into two so as to cover the guide and each has a heat shield that can move in the vertical direction. The right end rotation support means to which the restricting means is attached is disposed opposite to the welded integrated object of the tube and the disk so as to have a predetermined distance, and the surface of the welded integrated object is formed by the pressure applying means by the gas from the opening end of the pipe. While applying the internal pressure (5.0 to 50 mbar), heat with an oxyhydrogen flame while adjusting the burner angle (1800 to 2000 ° C.), adjust the internal pressure and temperature while detecting the curvature with the guide, and adjust the predetermined curvature. It processed so that it might become the R section.
[0030]
Example 2
3. A large quartz glass tube having an outer diameter of 314 mm, an inner diameter of 305 mm, a thickness of 4.5 mm, and a length of 1500 mm, with an outer diameter of 344 mm and an outer diameter of 344 mm at an end of 15 mm. A 7 mm quartz glass disk was inserted into the end of the enlarged diameter portion of the glass tube, welded according to Example 1, and processed to be an R portion having a predetermined curvature.
[0031]
According to Examples 1 and 2, five large round sealed quartz glass tubes were manufactured, and when the appearance, curvature, and thickness of the round sealed surface were measured, the appearance and curvature were all curved surfaces having a smooth predetermined curvature. All the wall thicknesses were within the range satisfying the predetermined tolerance at 4.3 to 4.7 mm without being cut from the center of the round seal surface to the outer edge.
[Brief description of the drawings]
[Fig. 1] Overall conceptual diagram of a large round-sealed quartz glass tube manufacturing device [Fig. 2] Conceptual diagram of opposing arrangement of quartz glass discs with the same diameter and thickness as the outer diameter of the end surface of the quartz glass tube [ FIG. 3 is a conceptual diagram in which a quartz glass disc is inserted into a glass tube having a diameter slightly smaller than the inner diameter of the quartz glass tube and substantially the same thickness. FIG. 4 is a conceptual diagram in which the weld end surface of the quartz glass tube is expanded in a tapered shape. FIG. 5 is a conceptual diagram showing an example of a round seal shape regulating means. FIG. 6 is a conceptual diagram showing an example of a round seal shape regulating means having a heat shield. FIG. 7 shows a conventional method for manufacturing a glass tube having a round sealed portion. [Fig. 8] Diagram showing a conventional method of forming a glass tube having a round seal [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of a large round sealed quartz glass tube 2 Tube 3 Plate 4 Round seal shape regulation means 5 Burner 6 Guide 7 Heat shield 8 Hot wire 9 Taper 10 Pressure application

Claims (5)

While holding one end of the quartz glass tube with a rotating support means, welding a quartz glass disk to the other end of the quartz glass tube with a high-temperature flame, expanding the welding end in a tapered shape and rotating the welded integral The sealed surface is controlled by a sealing shape restricting means movable in the tube axis direction and heated with a high-temperature flame, and the gas pressure in the quartz glass tube is adjusted to form the sealed surface into an R portion having a predetermined curvature. A manufacturing method for large round quartz glass tubes. 2. The large round quartz glass according to claim 1, wherein the quartz glass disc has the same thickness as the quartz glass tube, and the diameter thereof is the same as the outer diameter of the end face to which the quartz glass tube is welded or is smaller than the inner diameter. A method of manufacturing a tube. Rotating support means for holding the quartz glass tube and rotating the quartz glass tube around its axis, local heating means for generating a high-temperature flame, pressure applying means for adjusting the gas pressure in the quartz glass tube, and an integrated weld Apparatus for manufacturing a large round sealed quartz glass tube having round-sealed shape regulating means movable in the tube axis direction for regulating the curvature of the round-sealed surface. 4. The apparatus for manufacturing a large-sized round sealed quartz glass tube according to claim 3, wherein the round-sealed shape regulating means has curvature detecting means. 5. The apparatus for producing a large round sealed quartz glass tube according to claim 3, further comprising a movable heat blocking means that covers the round shape regulating means.

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