High-temperature tubular furnace

Abstract

1. A high-temperature tubular furnace comprising: a process tube (1) having a top cover (101) disposed at an upper end thereof and having a plurality of through holes (1011) formed in the top cover (101); a gas supply pipe (2) connected to the plurality of through holes (1011) in the top cover (101) of the process tube (1), wherein a process gas is introduced through the gas supply pipe (2) and the plurality of through holes (1011) in the top cover (101) of the process tube (1); and a wafer boat (3) disposed within the process tube (1) and comprising a support frame (301) and a plurality of support plates (302), wherein the plurality of support plates (302) are distributed in a plurality of layers along the length direction of the support frame (301) and are used to support a plurality of substrates (w), each substrate (w) being disposed on a certain support plate, and each support plate supporting the entire lower portion of each substrate (w). A plurality of support plates (302) are provided, and each support plate (302) supports the entire lower part of the substrate (w). This prevents the substrate (w) from being deformed downward during high-temperature processes at 1200°C or higher, which may cause lattice defects in the substrate (w), and improves chip yields.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing equipment, and particularly to high-temperature tube furnaces.

Background Art

[0002] High-temperature tube furnaces are mainly applied to semiconductor processes such as deposition and oxidizing annealing. Currently, the temperature of conventional semiconductor deposition processes is 800°C to 1100°C. However, with the development of semiconductor power devices and more advanced semiconductor process equipment, the process temperature requirements for high-temperature tube furnaces are becoming increasingly high. The conventional process temperature of 800°C to 1100°C can no longer meet the demand.

[0003] During the semiconductor process, in order to increase the output of the equipment by accelerating the diffusion rate of doped atoms in the silicon wafer and the deposition rate of the oxide film, it is necessary to make the process temperature higher than 1200°C. Usually, the process temperature is lower than 1300°C.

[0004] Usually, a special-shaped process tube made of quartz or silicon carbide is applied in the high-temperature tube furnace. In the high-temperature tube furnace, the melting point of quartz is about 1700°C. When the high-temperature tube furnace is used for a long time under high-temperature process conditions of 1200°C or higher, the upper part of the process tube is affected by its own weight and pressure. As a result, the center of the process tube tends to sink downward, causing the process tube to deform and unable to meet subsequent production needs.

[0005] The material of the substrate is usually silicon, and the melting point of the silicon substrate is about 1410°C. Also, as shown in Figure 1A, the wafer boat in the existing high-temperature tube furnace is provided with a support frame 11 and a plurality of support fins 12 connected thereto. There are three support fins 12 that determine one support surface to support each silicon substrate w. However, as shown in Figure 1B, the three support fins 12 can only support the peripheral edges of each silicon substrate w. When the high-temperature tubular furnace is used under high-temperature process conditions of 1200°C or higher, the center of the silicon substrate w tends to collapse downward. This worsens the deformation of the central region of the silicon substrate w, increasing the density of lattice dislocation defects in the substrate and resulting in a decrease in chip yield.

[0006] Therefore, conventional high-temperature tubular furnaces tend to deform or damage the process tubes, wafer boats, and silicon substrates under high-temperature process conditions, which leads to a reduced service life of the furnace. This, in turn, increases operating costs.

[0007] In other words, to solve the above problem, it is necessary to propose a new tubular furnace structure. [Overview of the project]

[0008] In view of the drawbacks of the prior art described above, the present invention aims to provide a high-temperature tubular furnace that solves the problem of the process tube, wafer boat, and substrate being prone to deformation in the prior art high-temperature tubular furnace.

[0009] To achieve the above-mentioned objectives and other related objectives, the present invention proposes a high-temperature tubular furnace comprising the following: This high-temperature tubular furnace is A process tube has a top cover positioned at its upper end, and the top cover has multiple through holes. A gas supply pipe is connected to a through-hole in the top cover of the process tube, and is used to introduce process gas into the process tube through the gas supply pipe and the through-hole in the top cover of the process tube. The process tube is arranged and comprises a support frame and a plurality of support plates, the plurality of support plates being distributed in multiple layers along the length of the support frame to support a plurality of substrates, and each substrate is a wafer boat arranged in each layer of support plates to hold the entire lower part of each substrate.

[0010] In one embodiment of the present invention, three guide grooves are provided in each layer of the support plate, and three suction cups are provided on a manipulator for picking up and placing substrates. The three guide grooves correspond to the three suction cups on the manipulator. Furthermore, the substrate is removed from the support plate or placed on the support plate by inserting the three suction cups into the three guide grooves.

[0011] In one embodiment of the present invention, each layer of the support plate is provided with two guide grooves, and a manipulator for picking up and placing substrates is provided with three suction cups. Two suction cups correspond to one guide groove, and the remaining suction cup corresponds to the other guide groove. The substrate is removed from the support plate or placed on the support plate by inserting the three suction cups into the two guide grooves.

[0012] In one embodiment of the present invention, the three suction cups of the manipulator are vacuum suction cups for adsorbing a substrate.

[0013] In one embodiment of the present invention, all three suction cups of the manipulator are solid suction cups, each of which is provided with a sealing ring, and the solid suction cups support the substrate via friction of the sealing ring.

[0014] In one embodiment of the present invention, at least two slots are provided on the periphery of each layer of the support plate, and at least two blocks are provided on the support frame at positions corresponding to each layer of the support plate, with at least two blocks corresponding one-to-one to at least two slots, and each layer of the support plate is attached to the blocks of the support frame via the slots.

[0015] In one embodiment of the present invention, there are four slots and four blocks, and the four blocks are arranged symmetrically on both sides in the circumferential direction of each layer of the support plate.

[0016] In one embodiment of the present invention, there are three slots, which are uniformly distributed around each support plate. The angle between two adjacent slots is 120°. There are also three blocks, which correspond one-to-one with the three slots.

[0017] In one embodiment of the present invention, the support plate and the support frame are made of different materials.

[0018] In one embodiment of the present invention, the support plate and the support frame are made of the same material and are integrally formed.

[0019] In one embodiment of the present invention, the material of the support plate is one of quartz, silicon carbide, diamond, graphite, and graphene.

[0020] In one embodiment of the present invention, the material of the support frame is one of quartz, silicon carbide, and silicon.

[0021] In one embodiment of the present invention, the support plate side that is in contact with the lower part of the substrate is provided with a plurality of protrusions or grooves.

[0022] In one embodiment of the present invention, the top cover of the process tube has a two-layer structure including an upper layer and a lower layer, and both layers have an arched structure.

[0023] In one embodiment of the present invention, a plurality of stiffeners are provided between the upper and lower layers of the top cover, connecting the upper and lower layers of the top cover.

[0024] In one embodiment of the present invention, the top cover has a two-layer structure including an upper layer and a lower layer. The upper layer of the top cover has an arched structure, and the lower layer of the top cover has a planar structure. In addition, multiple stiffeners are placed between the upper and lower layers of the top cover, connecting the upper and lower layers of the top cover.

[0025] In one embodiment of the present invention, the material of the process tube is quartz or silicon carbide.

[0026] In one embodiment of the present invention, the high-temperature tubular furnace further includes a liner tube provided in a sleeve shape around the process tube, and a heating element provided in a sleeve shape around the liner tube.

[0027] In one embodiment of the present invention, the material of the liner tube is quartz or silicon carbide.

[0028] As described above, the high-temperature tubular furnace proposed by the present invention has the following beneficial effects compared with the prior art. 1. In the high-temperature tubular furnace provided by the present invention, a plurality of layers of support plates are provided, and each layer supports the entire lower part of the substrate. Thereby, it is possible to avoid the occurrence of lattice defects in the substrate due to the downward deformation of the substrate during a high-temperature process of 1200 °C or higher, and improve the yield of the chips. 2. In the high-temperature tubular furnace provided by the present invention, by making the top cover of the process tube into a two-layer arch structure, it becomes difficult for the lower layer of the top cover of the process tube to sink during a high-temperature process of 1200 °C or higher, stress and deformation in the top cover of the process tube are prevented, the service life of the high-temperature tubular furnace is extended, and the usage cost is reduced.

Brief Description of the Drawings

[0029] FIG. 1A is a schematic diagram showing the support fins and the support substrate of a wafer boat in the prior art. FIG. 1B is a diagram of the support fins and the support substrate in the prior art, showing the state where the substrate sinks at high temperature. FIG. 2 is a schematic diagram showing the high-temperature tubular furnace provided by the first embodiment of the present invention. FIG. 3 is a schematic diagram showing the wafer boat provided by the first embodiment of the present invention. Figure 4A is a top view showing a support plate in the direction AA of Figure 3, provided by a first embodiment of the present invention. Figure 4B is a schematic diagram showing a manipulator working in conjunction with a support plate provided by the first embodiment of the present invention. Figure 4C is a schematic diagram showing a manipulator for inserting a suction cup into a guide groove of a support plate provided by a first embodiment of the present invention. Figures 5A, 5B, and 5C are a bottom view, a top view, and a front view, respectively, showing suction cups inserted into guide grooves on a manipulator provided in a first embodiment of the present invention. Figure 6A is a schematic diagram showing a support plate that works in conjunction with a manipulator provided by a second embodiment of the present invention. Figures 6B, 6C, and 6D are a bottom view, a top view, and a front view, respectively, showing a vacuum suction cup inserted into a guide groove to remove a substrate from a manipulator provided in a second embodiment of the present invention. Figure 7 is a schematic diagram showing three slots on a support plate that work in conjunction with three blocks on a support frame provided by a third embodiment of the present invention. Figures 8A, 8B, and 8C are cross-sectional views of different types of support plates in the B-B' direction shown in Figure 4A, provided by the first and other embodiments of the present invention, respectively. Figures 9A and 9B are partial and cross-sectional views, respectively, of the top cover of a process tube provided by a first embodiment of the present invention. Figures 10A and 10B are partial and cross-sectional views, respectively, of the top cover of a process tube provided by a fourth embodiment of the present invention. Figures 11A and 11B are partial and cross-sectional views, respectively, of the top cover of a process tube provided by a fifth embodiment of the present invention. [Modes for carrying out the invention]

[0030] Embodiments of the present invention will be described through the following specific examples. Those skilled in the art will readily understand other advantages and benefits of the present invention from the disclosure herein. The present invention may be carried out or applied in various other specific embodiments. The details herein may be modified or altered in various ways based on different viewpoints and uses without departing from the spirit of the invention.

[0031] Please refer to Figures 2 to 11B. It should be noted that the drawings provided in this embodiment only schematically illustrate the basic concept of the present invention. The drawings merely show the parts related to the present invention, rather than the number, shape, and size of the parts in actual implementation, but the shape, number, and proportion of each part in actual implementation can be arbitrarily changed, and the layout of the parts can also be made more complex.

[0032] First Embodiment As shown in Figure 2, the present invention provides a high-temperature tubular furnace. Specifically, the high-temperature tubular furnace comprises a process tube 1, a gas supply tube 2, a wafer boat 3, an external gas tube 4, a liner tube 5, and a heating element 6.

[0033] Here, as shown in Figures 9A and 9B, a top cover 101 is provided on the upper part of the process tube 1, and a through hole 1011 is provided on the top cover 101. In the first embodiment, the top cover 101 has a two-layer structure including an upper layer 1012 and a lower layer 1013. Both the upper layer 1012 and the lower layer 1013 of the top cover 101 have an arch structure to suppress the collapse of the top cover 101 at high temperatures of 1200°C or higher. In addition, a cavity 1014 is formed between the upper layer 1012 and the lower layer 1013 of the top cover 101, and a through hole 1011 is provided on the lower layer 1013 of the top cover 101. The material of the process tube 1 is quartz or silicon carbide (SiC).

[0034] As shown in Figures 2, 9A, and 9B, the gas supply pipe 2 is positioned along the side wall of the process tube 1. The first end (lower end) of the gas supply pipe 2 is connected to the external gas pipe 4, and the second end (upper end) is connected to the cavity 1014 on the top cover 101. The process gas supplied by the external gas pipe 4 is introduced into the process tube 1 through the gas supply pipe 2 and the through-hole 1011 on the top cover 101 of the process tube 1. The liner tube 5 is positioned around the process tube 1. The material of the liner tube 5 is quartz or silicon carbide (SiC). The heating element 6 is provided in a sleeve-like manner around the liner tube 5.

[0035] As shown in Figure 3, a wafer boat 3 is placed inside the process tube 1. Specifically, the wafer boat 3 comprises a support frame 301 and a support plate 302. The support plate 302 has multiple layers distributed along the length of the support frame 301 and supports multiple substrates w. Each substrate w is placed on each layer of the support plate 302, and each layer of the support plate 302 supports the entire underside of each substrate w. This reduces the effect of gravity on the surface stress of the substrates w and reduces the density of lattice dislocation defects in the substrates w.

[0036] As shown in Figure 4A, Figure 4A is a top view showing the support plate in the AA direction shown in Figure 3, and Figure 4B is a schematic diagram showing the manipulator 7 that works in conjunction with the support plate 302. In the first embodiment, the manipulator 7 for picking up and placing the substrate w is equipped with three suction cups 701. Each layer of the support plate 302 is provided with three guide grooves 3021, and the three guide grooves 3021 correspond to the three suction cups 701 on the manipulator 7.

[0037] In this embodiment, the three suction cups 701 on the manipulator 7 may be vacuum suction cups for adsorbing the substrate. As shown in Figure 4C, when the manipulator 7 places the substrate w into or removes it from each layer of the support plate 302, the three vacuum suction cups 701 provided on the manipulator 7 firmly adsorb the substrate w, preventing the substrate w from falling or shifting.

[0038] In another embodiment, the three suction cups 701 on the manipulator 7 may be solid suction cups, in which case each solid suction cup 701 is provided with a sealing ring (not shown in the accompanying drawings). The solid suction cups 701 support the substrate w by friction of the sealing ring, preventing the substrate w from falling or shifting. The solid suction cups 701 may also be metal suction cups, ceramic suction cups, or carbon fiber suction cups, etc.

[0039] In this embodiment, as shown in Figures 5A to 5C, the three vacuum suction cups 701 on the manipulator 7 are inserted into three guide grooves 3021 to attract the substrate w, thereby removing the support plate 302 from the substrate w or placing the substrate w on the support plate 302. The size of the three guide grooves 3021 in this embodiment matches the size of the three vacuum suction cups 701. This increases the contact area between the support plate 3021 and the substrate w, effectively preventing the substrate w from deforming downward at high temperatures of 1200°C or higher.

[0040] In this embodiment, the three vacuum suction cups 701 on the manipulator 7 are distributed in a roughly isosceles triangular shape.

[0041] Figure 8A is a cross-sectional view of the support plate 302 provided in the first embodiment, along the BB' direction shown in Figure 4A. Each layer of the support plate 302 is in planar contact with the lower part of the substrate w. This increases the contact area between the support plate 302 and the substrate w, ensuring that the substrate w is not easily deformed downward at high temperatures, and thus avoiding lattice defects in the substrate w.

[0042] In another embodiment of the present invention, the support plate 302' provided in a different embodiment, as shown in Figure 8B, is represented in a cross-sectional view in the BB' direction shown in Figure 4A. Multiple protrusions 3024 are provided on each layer side of the support plate 302'' that is in contact with the lower part of the substrate w, so that a gap is secured between the support plate 302'' and the lower part of the substrate w. In this embodiment, the substrate w is in point contact with the support plate 302''. This improves upon the disadvantage of uneven heating of the substrate w compared to the first embodiment, where each layer of the support plate 302' is in contact with the lower part of the substrate w.

[0043] Figure 8C is a cross-sectional view of a support plate 302'' provided in another embodiment, in the direction BB' shown in Figure 4A. Multiple grooves 3025 are provided on each layer side of the support plate 302'' that is in contact with the lower part of the substrate w, so that a gap is secured between the support plate 302'' and the lower part of the substrate w. Since the substrate w is in point contact with the support plate 302'', the drawback of uneven heating of the substrate w is improved.

[0044] In the first embodiment, the support plate 302 and the multiple layers of the support frame 301 are made of different materials. In the high-temperature technology process, there are differences in the thermal expansion coefficients of the different materials, and stress is generated between the support plate 302 and the support frame 301, which have different thermal expansion coefficients. This easily causes damage and deformation of the support frame 301 and easily generates impurity particles that contaminate the substrate w.

[0045] Therefore, as shown in Figures 4A, 4C, 5A, and 5B, in order to avoid the generation of stress between the support plate 302 and the support frame 301, which are made of multiple materials with different coefficients of thermal expansion, four grooves (not shown in the accompanying drawings) are distributed around each layer of the support plate 302. The support frame 301 is provided with four corresponding blocks 3011 at positions corresponding to each layer of the support plate 302. In the first embodiment, the four blocks 3011 are distributed symmetrically on both sides in the circumferential direction of each layer of the support plate 302, and each layer of the support plate 302 is clamped onto the blocks (3011) of the support frame 301 via slots. By doing so, stress is not generated between the support plate 302 and the support frame 301, which have different coefficients of thermal expansion, during the high-temperature process, thus avoiding the generation of impurity particles that contaminate the substrate w.

[0046] In another embodiment, to avoid stress between the support plate 302 and the support frame 301, the support plate 302 and the support frame 301 may be made of the same material and formed integrally. This effectively prevents impurity particles generated by the deformation of the support frame 301 and the support plate 302 due to stress from contaminating the substrate w.

[0047] In the first embodiment, the thickness of the support plate 302 is 1 to 3 mm. The material of the support plate 302 may be any of quartz, silicon carbide, diamond, graphite, and graphene. The material of the support frame 301 may be any of quartz, silicon carbide, and silicon. In other embodiments, the substrate w may be made of a material other than silicon.

[0048] Second Embodiment As shown in Figures 6A to 6D, the second embodiment provides a high-temperature tubular furnace that differs from the first embodiment in the following respects.

[0049] As shown in Figure 6A, in the second embodiment, the manipulator 7 for picking up and placing the substrate w is provided with three suction cups, and each layer of the support plate 302 is provided with two guide grooves. In the second embodiment, all three suction cups are vacuum suction cups. Two vacuum suction cups 702 on the manipulator 7 correspond to one guide groove 3022, and the remaining vacuum suction cup 703 corresponds to the other guide groove 3023. As shown in Figures 6B, 6C, and 6D, the three vacuum suction cups on the manipulator 7 are inserted into the two guide grooves to remove the substrate w from the support plate 302 or to place it on the support plate 302.

[0050] Other settings in this embodiment are the same as in the first embodiment. They will not be repeated here.

[0051] Third Embodiment The third embodiment provides a high-temperature tubular furnace that differs from the first embodiment in the following respects.

[0052] As shown in Figure 7, in the third embodiment, in order to avoid stress between the support plate 302 and the support frame 301, which are made of multiple materials having different coefficients of thermal expansion, three slots are provided on the support plate 302 and three blocks 3011 are provided on the support frame 301. The three blocks 3011 are uniformly distributed around each layer of the support plate 302 such that the angle between two adjacent blocks 3011 is 120°. Each layer of the support plate 302 is clamped onto the blocks 3011 of the support frame 301 via the slots.

[0053] Other settings in this embodiment are the same as in the first embodiment. They will not be repeated here.

[0054] Fourth Embodiment The fourth embodiment provides a high-temperature tubular furnace that differs from the first embodiment in the following respects.

[0055] As shown in Figures 10A and 10B, in the fourth embodiment, both the upper layer 1012 and the lower layer 1013 of the top cover 101 located at the top of the process tube 1 have an arched structure, and a stiffener 1015 is provided between the upper layer 1012 and the lower layer 1013 of the top cover 101. The stiffener 1015 connects the upper layer 1012 and the lower layer 1013 of the top cover 101, reducing the possibility of the upper layer 1012 and the lower layer 1013 of the top cover 101 collapsing due to high temperatures, thereby ensuring the stability of the process tube 1 at high temperatures.

[0056] Other settings in this embodiment are the same as in the first embodiment. They will not be repeated here.

[0057] Fifth Embodiment The fifth embodiment provides a high-temperature tubular furnace that differs from the first embodiment in the following respects.

[0058] As shown in Figures 11A and 11B, in the fifth embodiment, the top cover 101 at the upper end of the process tube 1 has a two-layer structure including an upper layer 1012 and a lower layer 1013. The upper layer 1012 of the top cover 101 has an arched structure, and the lower layer 1013 of the top cover 101 has a planar structure. To prevent the lower layer 1013 of the planar top cover 101 from collapsing at high temperatures of 1200°C or higher, a stiffener 1015 is provided between the upper layer 1012 and the lower layer 1013 of the top cover 101, thereby connecting the upper layer 1012 and the lower layer 1013 of the top cover 101.

[0059] Other settings in this embodiment are the same as in the first embodiment. They will not be repeated here.

[0060] The present invention has been disclosed in specific and detailed terms through the above embodiments and related drawings so that those skilled in the art can implement it as appropriate. However, the above embodiments are for illustrative purposes only and are not intended to limit the present invention. The scope of the claims of the present invention is defined by the claims of the present invention. Modifications of the number of components disclosed herein, or substitutions of equivalent components, should also be considered within the scope of the claims of the present invention.

Claims

1. A process tube having a top cover positioned at its upper end, the top cover having multiple through holes, A gas supply pipe connected to the plurality of through holes in the top cover of the process tube, the gas supply pipe for introducing process gas into the process tube through the gas supply pipe and the plurality of through holes in the top cover of the process tube, A wafer boat is provided, which is located within the process tube and comprises a support frame and a plurality of support plates, wherein the plurality of support plates are distributed in a plurality of layers along the length direction of the support frame to support a plurality of substrates, each substrate is placed in each layer of the support plates, and each layer of the support plates supports the entirety of each substrate. Each layer of the support plate is provided with three guide grooves, and the manipulator for picking up and placing the multiple substrates is provided with three suction cups, the three guide grooves correspond to the three suction cups on the manipulator, and the substrates are removed from the support plate or placed on the support plate when the three suction cups are inserted into the three guide grooves. Or, A high-temperature tubular furnace characterized in that each layer of the support plate is provided with two guide grooves, a manipulator for picking up and placing the plurality of substrates is provided with three suction cups, two of which correspond to one guide groove and the remaining suction cup corresponds to the other guide groove, and the substrates are removed from the support plate or placed on the support plate by inserting the three suction cups into the two guide grooves.

2. The high-temperature tubular furnace according to claim 1, characterized in that the three suction cups on the manipulator are vacuum suction cups for adsorbing the substrate.

3. The high-temperature tubular furnace according to claim 1, characterized in that all three suction cups on the manipulator are solid suction cups, each of the three suction cups is provided with a sealing ring, and the plurality of solid suction cups support the substrate via friction of the sealing rings.

4. The high-temperature tubular furnace according to claim 1, characterized in that at least two slots are provided on the periphery of each layer of the support plate, at least two blocks are provided on the support frame at positions corresponding to each layer of the support plate, the at least two blocks correspond one-to-one with at least two slots, and each layer of the support plate is attached to the plurality of blocks of the support frame via the slots.

5. The high-temperature tubular furnace according to claim 4, characterized in that the number of the plurality of slots is four, the number of the plurality of blocks is four, and the four blocks are arranged symmetrically on both sides in the circumferential direction of each layer of the support plate.

6. The high-temperature tubular furnace according to claim 4, characterized in that the number of the plurality of slots is three, the three slots are uniformly distributed around each support plate, the angle between two adjacent slots is 120°, the number of the plurality of blocks is three, and there is a one-to-one correspondence between the three slots.

7. The high-temperature tubular furnace according to claim 1, characterized in that the support plate and the support frame are made of different materials.

8. The high-temperature tubular furnace according to claim 1, characterized in that the support plate and the support frame are made of the same material and are integrally formed.

9. The high-temperature tubular furnace according to claim 1, characterized in that the material of the support plate is one of quartz, silicon carbide, diamond, graphite, and graphene.

10. The high-temperature tubular furnace according to claim 1, characterized in that the material of the support frame is one of quartz, silicon carbide, and silicon.

11. The high-temperature tubular furnace according to claim 1, characterized in that a plurality of protrusions or grooves are provided on the support plate side that is in contact with the lower part of the substrate.

12. The high-temperature tubular furnace according to claim 1, characterized in that the top cover of the process tube has a two-layer structure including an upper layer and a lower layer, and the upper and lower layers of the top cover have an arch structure.

13. The high-temperature tubular furnace according to claim 12, characterized in that a plurality of stiffeners are provided between the upper and lower layers of the top cover, connecting the upper and lower layers of the top cover.

14. The high-temperature tubular furnace according to claim 1, characterized in that the top cover has a two-layer structure including an upper layer and a lower layer, the upper layer of the top cover has an arch structure, the lower layer of the top cover has a planar structure, and a plurality of stiffeners are arranged between the upper and lower layers of the top cover, connecting the upper and lower layers of the top cover.

15. The high-temperature tubular furnace according to claim 1, characterized in that the material of the process tube is quartz or silicon carbide.

16. A high-temperature tubular furnace according to claim 1, A liner tube is provided in a sleeve shape around the aforementioned process tube, A high-temperature tubular furnace further comprising a plurality of heating elements provided in a sleeve-like manner around the liner tube.

17. The high-temperature tubular furnace according to claim 16, characterized in that the material of the liner tube is quartz or silicon carbide.

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