Gasifier

Abstract

Provided is a vaporizer that improves the close contact between a metal inner heater block and an inner tube made of heat-resistant glass to achieve high-temperature heating of a liquid raw material, thereby improving heat conduction from the inner heater. The vaporizer (A) is composed of an atomizer (7), a vaporizer body (Ah), and a heating portion (Ak). The heating portion (Ak) is composed of an inner heater block (3) and an inner heater (9). The inner tube (2) is made of heat-resistant glass and has an outer diameter smaller than the inner diameter of the hollow vaporizer body (Ah). The inner heater block (3) is composed of split bodies (31 to 3n) split along its central axis (CL) and an elastic material (8). The elastic material (8) is arranged between the split bodies (31 to 3n) and acts to press the split bodies (31 to 3n) in a separation direction and press them against the inner circumferential surface of the inner tube (2). The inner heaters (91 to 9n) are respectively buried in the split bodies (31 to 3n).

Description

Technical Field

[0001] The present invention relates to a glass vaporizer having excellent thermal conductivity, and in particular to a glass vaporizer used for manufacturing semiconductors and forming optical waveguides. Background Art

[0002] There are wet oxidation and dry oxidation as types of thermal oxidation methods for semiconductor materials such as Si and SiC. Water is used in wet oxidation. H2O is flowed into the furnace as a gas (water vapor), and the oxygen in the water is used to grow the oxide film. It is characterized by a fast oxidation rate. Therefore, this method is used when a thicker film thickness is required. On the other hand, dry oxidation uses oxygen in the growth of the oxide film. This is opposite to wet oxidation, and the growth rate is slow. In recent years, in order to further increase the growth rate of the oxide film, hydrogen peroxide (H2O2) is used instead of water (H2O). On the other hand, as a use other than semiconductors, there is the formation of optical waveguides (see Patent Document 1). In this case, in order to deposit silicon dioxide (SiO2) with a thickness of 10 to 25 μm, a long deposition time is required in the oxidation method using H2O. If hydrogen peroxide (H2O2) is used instead of H2O, the time can be greatly shortened.

[0003] For this purpose, a large amount of hydrogen peroxide solution needs to be gasified and fed into the reaction furnace. As a device for such a purpose, a device such as that shown in Patent Document 1 has been proposed.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-337240

[0007] Patent Document 2: Japanese Patent No. 6203207 Summary of the invention

[0008] Problems to be Solved by the Invention

[0009] The vaporizer described in Patent Document 1, which vaporizes a hydrogen peroxide solution to generate an oxidizing gas, covers the lower half of the vaporizer of a hollow spherical container similar to a flask containing a hydrogen peroxide solution from the outside with a heater, and the hollow spherical container is heated to 100 to 130° C. The water vapor gas containing the vaporized hydrogen peroxide gas flows into the reactor through the gas supply pipe. This device is a device that only heats the hydrogen peroxide solution to vaporize it, and its disadvantage is that the concentration of hydrogen peroxide changes as the hydrogen peroxide solution in the vaporizer evaporates. In addition, it is difficult to keep the flow rate of hydrogen peroxide constant, and it is not clear how much flow rate is flowing.

[0010] Therefore, the inventor proposed the invention described in Patent Document 2. The vaporizer is composed of an atomizer that atomizes and sprays a liquid raw material, a hollow outer tube connected to a spray port of the atomizer, an inner tube accommodated in the outer tube, an external heater block provided on the outer side of the outer tube, an internal heater block inserted into the inner side of the inner tube, an external heater buried in the external heater block, and an internal heater buried in the internal heater block.

[0011] To prevent contamination, the vaporizer is made of quartz glass except for two heater blocks and two heaters. Moreover, the two heater blocks are made of aluminum with good thermal conductivity.

[0012] The space in the outer tube facing the spray port of the atomizer is the atomization space, and the gap between the outer tube and the inner tube connected to the atomization space is the vaporization gap. The liquid raw material flows in the vaporization gap and is heated and vaporized.

[0013] In this heating operation, since the inner heater block is made of aluminum, which has a significantly higher thermal expansion coefficient than quartz, when the temperature is set to a high temperature, in order to prevent the quartz inner tube from being damaged by the thermal expansion of the aluminum inner heater block, the outer diameter of the inner heater block is made smaller than the inner diameter of the quartz inner tube, and a margin is left to a degree that is not affected by thermal expansion to obtain a larger space. However, since this gap is an air layer with high thermal insulation, it is difficult for the heat of the inner heater to be transferred from the inner heater block to the inner tube, and the gasification performance is significantly hindered.

[0014] In order to improve this situation, in actual products, heat transfer paste is applied to fill the gap between the inner heater block and the quartz inner tube. However, if the flow rate of the liquid raw material to be vaporized is increased, a higher temperature is required. If the temperature is set to a high temperature, the solvent as a component of the heat transfer paste evaporates, leaving only the solid component. In this way, the gap after the solvent evaporates is filled with air with high heat insulation properties, which significantly reduces the heat transfer efficiency and the vaporization performance, resulting in the problem that the target flow rate of the liquid raw material to be vaporized cannot be obtained.

[0015] The present invention is proposed in view of the existing problems, and its purpose is to provide a vaporizer, in order to achieve high-temperature heating of liquid raw materials, minimize the use of heat transfer paste, improve the close contact between the metal (aluminum) inner heater block and the heat-resistant glass (quartz) inner tube, and improve the heat conduction from the inner heater block after being heated by the inner heater.

[0016] Means for solving problems

[0017] The invention described in claim 1 relates to a vaporizer A having excellent thermal conductivity, characterized in that:

[0018] Gasifier A consists of the following structure:

[0019] an atomizer 7, which atomizes and sprays the liquid raw material L;

[0020] A hollow vaporizer body Ah, which has one end connected to the spray port 73 of the atomizer 7 and has an outlet nozzle 11 as an outlet of the vaporized gas G2 at the other end; and

[0021] The heating unit Ak is housed in the vaporizer body Ah.

[0022] The heating unit Ak is composed of the following structure:

[0023] An inner tube 2 made of heat-resistant glass, having an outer diameter smaller than the inner diameter of the vaporizer body Ah, and a front end head 2a as an insertion end is closed;

[0024] an inner heater block 3 inserted into the inner tube 2; and

[0025] The internal heater 9 is embedded in the internal heater block 3.

[0026] The outlet nozzle 11 is provided so as to communicate with a gasification gap R formed between the inner peripheral surface of the gasifier body Ah and the outer peripheral surface of the inner tube 2.

[0027] The inner heater block 3 is composed of a plurality of divided bodies 31 to 3n divided along the central axis CL of the inner heater block 3 and an elastic material 8.

[0028] The elastic material 8 is disposed between the split bodies 31 to 3n and functions to press the split bodies 31 to 3n in a separation direction and to press the outer peripheral surfaces of the split bodies 31 to 3n against the inner peripheral surface of the inner tube 2.

[0029] The internal heaters 91 to 9n are respectively buried in the divided bodies 31 to 3n.

[0030] Invention claim 2 is characterized in that, in the vaporizer A described in invention claim 1, the heat-resistant glass is quartz glass.

[0031] Effects of the Invention

[0032] Since the vaporizer A of the present invention has the above-mentioned structure, even if the divided bodies 31 to 3n undergo thermal expansion when the temperature rises, the elastic material 8 contracts accordingly to absorb the thermal expansion, and the elastic material 8 presses the outer peripheral surfaces of the divided bodies 31 to 3n against the inner peripheral surface of the inner tube 2. Therefore, the inner tube 2 and the divided bodies 31 to 3n constituting the inner heater block 3 can be maintained in close contact without damaging the inner tube 2 made of heat-resistant glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a partially cutaway front view of one embodiment of the present invention.

[0034] Figure 2 yes Figure 1 A sectional view taken along arrow XX of the first embodiment of the present invention.

[0035] Figure 3 yes Figure 1 A sectional view of a second embodiment of the present invention.

[0036] Figure 4 This is a structural diagram of a semiconductor manufacturing apparatus using the vaporizer of the present invention. DETAILED DESCRIPTION

[0037] Hereinafter, the present invention will be described with reference to the drawings. The vaporizer A is composed of an atomizer 7, a vaporizer body Ah, and a heating unit Ak.

[0038] The vaporizer body Ah is composed of a hollow cylindrical outer tube 1, a divided external heater block 5, an external heater 4, and an outlet nozzle 11. As described later, the vaporizer body Ah is provided with a temperature sensor 12 as necessary.

[0039] The heating unit Ak is composed of the inner tube 2 , the inner heater block 3 , the inner heater 9 , and the temperature sensor 10 .

[0040] The liquid raw material L applicable to the vaporizer A can be any raw material as long as it is a raw material used after vaporization (for example, various liquid raw materials used in semiconductor manufacturing), and is set to a hydrogen peroxide solution in this case. When the vaporizer A is used for vaporization of a hydrogen peroxide solution and a water vapor gas (gasification gas G2) containing hydrogen peroxide of extremely high purity is required, such as in a semiconductor manufacturing device, the parts in contact with the water vapor gas (gasification gas G2) containing hydrogen peroxide are made of glass (for example, "quartz glass") that is not corroded by the water vapor gas (gasification gas G2) containing hydrogen peroxide under a high temperature environment, which are the atomizer 7, the outer tube 1, the inner tube 2, and the outlet nozzle 11 in this case.

[0041] In other fields, heat-resistant glass such as Pyrex (registered trademark) glass can also be used.

[0042] The external heater block 5 of the vaporizer body Ah is formed by dividing a cylindrical member made of metal (aluminum in this embodiment) into n parts along the central axis, and internally houses an external heater 4 and a temperature sensor 12 provided as required. The external heater 4 is also divided into n parts according to the external heater block 5, and the temperature sensor 12 is also inserted into each divided body of the external heater block 5.

[0043] exist Figure 2 and Figure 3In the figure, the external heater block 5 is divided into two parts, and the external heater 4 is also divided into two parts according to the external heater block 5 and accommodated in the divided parts 51 and 52 of the external heater block 5. The divided parts of the external heater 4 are denoted by reference numerals 41 and 42.

[0044] Furthermore, fixing bands 80 having a tightening force are fitted at multiple locations on the outer peripheries of the split bodies 51 and 52 of the outer heater blocks 5 , and the entire inner peripheries of the split bodies are pressed against the outer periphery of the outer tube 1 to make them contact with the outer periphery of the outer tube 1 .

[0045] In this manner, the outer heater block 5 is mounted so that the entire inner peripheral surface thereof comes into contact with the outer peripheral surface of the outer tube 1 made of heat-resistant glass (for example, quartz glass).

[0046] The temperature sensor 12 may be provided in each of the divided bodies 51 and 52 of the external heater block 5 .

[0047] As described above, one end of the outer tube 1 is closed by a cylindrical hollow tube, and the spray gas pipe 7a of the atomizer 7 described later is connected to the closed end 1a, and the spray port 73 is opened. In addition, the outlet nozzle 11 communicating with the gasification gap R described later is connected to the outer peripheral surface on the opposite side of the closed end 1a of the outer tube 1.

[0048] The atomizer 7 is composed of a spray gas pipe 7a and a liquid raw material introduction pipe 7b. The spray gas pipe 7a is connected to the end of the outer tube 1. The liquid raw material introduction pipe 7b is at a right angle or a nearly right angle to the spray gas pipe 7a, or is not shown but is inclined in the flow direction of the atomizing gas. The spray gas pipe 7a is penetrated by a main supply hole 7c for the atomizing gas G1 to pass through, and the liquid raw material introduction pipe 7b is penetrated by a sub-supply hole 7d connected to the main supply hole 7c. The inner diameter of the main supply hole 7c is larger than the inner diameter of the sub-supply hole 7d, and the outlet of the main supply hole 7c is narrowed, thereby forming the above-mentioned spray port 73. The outlet portion of the spray gas pipe 7a of the atomizer 7 is connected to the outer tube 1.

[0049] Furthermore, the liquid raw material introduction pipe 7b is connected to a liquid flow controller E described later.

[0050] The front end head 2a as the insertion end side of the inner tube 2 is closed and formed into a hemispherical shape. In the embodiment of the accompanying drawings, the shape of the front end head 2a is a hemispherical shape, but of course it is not limited to this, and it can also be a rotating ellipsoid surface, a rotating parabola or a cone.

[0051] The other end of the inner tube 2 is open, and the inner heater block 3 is inserted from the open end.

[0052] The inner heater block 3 is divided into a plurality of parts along the axial direction (central axis CL). Figure 2 is an example of splitting into two parts, Figure 3is an example of being divided into three parts. Each segment 31 to 3n is divided equally. Figure 2 In the case of a semicircular cross section, Figure 3 In the case of being divided into two parts, it is fan-shaped. In addition, the number of divisions is not limited. When divided into two parts, the divided bodies are represented by 31 and 32, and when divided into three parts, they are represented by 31 to 33. In the case of being divided into n parts, although not shown in the figure, they are 31 to 3n (n is an integer greater than 2). The material of the divided bodies 31 to 3n of the internal heater block 3 is set to aluminum in this embodiment. This is because it has many advantages such as low density, high thermal conductivity, low price, easy machining, and a certain degree of corrosion resistance. Of course, materials other than aluminum can also be used. Metals with high thermal conductivity such as copper, brass, iron, and stainless steel can be used. This also applies to the above-mentioned external heater block 5.

[0053] The outer surface shape of the inner heater block 3 formed by the assembly of the segmented bodies 31 to 3n is consistent with the inner surface shape of the inner tube 2, and is expanded in the radial direction by the action of the elastic material 8 described later, so that the outer surfaces of the segmented bodies 31 to 3n are respectively pressed against the inner surface of the inner tube 2. In this case, if the curvature of the outer peripheral surface of each segmented body 31 to 3n when heated to a certain temperature (the vaporization temperature of the liquid raw material L) is consistent with the curvature of the inner surface of the inner tube 2, then at the required temperature (the vaporization temperature of the liquid raw material L), the entire outer peripheral surface of the segmented bodies 31 to 3n constituting the inner heater block 3 is in contact with the inner surface of the inner tube 2.

[0054] As described above, the internal heater block 3 can be divided into multiple parts, and the description here focuses on the internal heater block 3 divided into three parts. The internal heaters 91 to 93 and the temperature sensors 101 to 103 are respectively inserted into the divided bodies 31 to 33 of the internal heater block 3 divided into three parts.

[0055] Furthermore, gaps C are provided between the facing surfaces 31m to 33m of the segmented bodies 31 to 33 having a fan-shaped cross section, and spring receiving holes 35 are provided at mutually facing positions on the facing surfaces 31m to 33m. The spring receiving holes 35 are provided in pairs at the front end and the base end of the inner heater block 3, and a pair is provided in each of the three gaps C, so that three sets are provided.

[0056] The spring receiving holes 35 of the split bodies 31 to 33 contain an elastic material 8. The elastic material 8 applies pressure in a direction to expand the gap C between the facing surfaces 31m to 33m of the split bodies 31 to 33, and therefore, a coil spring made of a material having excellent heat resistance is used here. As the elastic material 8 other than the coil spring, a wave washer, a leaf spring, etc. can also be used.

[0057] The elastic force of the elastic material 8 is selected to be strong enough to prevent the inner tube 2 from being damaged. In order to improve the heat transfer efficiency, the gaps C between the facing surfaces 31m to 33m of the divided bodies 31 to 33 may be filled with a heat transfer paste having good heat transfer properties.

[0058] On the outer circumferential surface of the inner tube 2, at least three tiny protrusions 6 are provided on the same circumference in two rows of rings at the front and rear ends of the tip and base ends. When the inner tube 2 is inserted into the outer tube 1, the tiny protrusions 6 come into contact with the inner circumferential surface of the outer tube 1, and a uniform and sufficiently narrow gasification gap R is formed over the entire circumference between the inner tube 2 and the outer tube 1. The gasification gap R is connected to the outlet nozzle 11 at the base end side of the outer tube 1 as described above. The outlet nozzle 11 is connected to, for example, a reactor H for oxidation of a silicon substrate.

[0059] The width W of the gap R for gasification is not particularly limited, but from the perspective of gasification efficiency, the width W is preferably within a range that forms a temperature boundary layer with a high heat transfer coefficient. That is, if the temperature of the outer peripheral surface of the inner tube 2 or the inner peripheral surface of the outer tube 1 is set to the wall temperature, the fluid temperature gradually decreases as it moves away from these walls, and becomes a constant temperature (uniform flow temperature) at a certain position. The range from the wall to the constant temperature is the temperature boundary layer. It is preferred that the width W of the gap R for gasification is within this range. In this way, the temperature of the circulating fluid Q flowing in the gap R for gasification is maintained at a temperature close to the wall temperature.

[0060] The open ends of the inner tube 2 and the outer tube 1 on the heater insertion side are fused throughout the entire circumference, and the open end of the heater insertion side of the vaporization gap R is closed throughout the entire circumference. The front end head 2a of the inner tube 2 housed in the outer tube 1 faces the spray port 73, and an atomization space M is provided between the closed end 1a provided with the spray port 73 and the front end head 2a. Moreover, the vaporization gap R is connected to the atomization space M throughout the entire circumference.

[0061] As a heat source, an electric heater is used. In the embodiment of the drawing, an inner heater 9 and an outer heater 4 are used. Of course, if heating is sufficient, only the inner heater 9 may be used. As described above, the inner heater 9 is inserted into the inner side of the divided bodies 31 to 33 respectively. The inner heaters inserted are indicated by reference numerals 91 to 93.

[0062] In addition, in the past, since the outer diameter of the inner heater block 3 was made to take into account the thermal expansion of the inner heater block 3 relative to the inner diameter of the inner tube 2 with a low thermal expansion coefficient, a large gap was generated between the two, and a large amount of heat transfer paste for bonding had to be used. However, in the present invention, the outer peripheral surface of the divided bodies 31 to 33 of the inner heater block 3 is pressed against the inner peripheral surface of the inner tube 2 by the entire surface, so that in principle, it is no longer necessary to use heat transfer paste. However, although the divided bodies 31 to 33 of the inner heater block 3 are machined products of metal materials and their outer shapes are accurately machined, since the inner tube 2 is heat-resistant glass (quartz glass), its processing accuracy is inferior to that of machine processing. Therefore, it is allowed to use a very small amount of heat transfer paste to the extent that the overall thermal conductivity will not be damaged even if the heat transfer paste is deteriorated by heat.

[0063] As for the temperature sensor 10, each inner heater 91 to 93 is equipped with a temperature sensor 101 to 103, and the temperature of the inner heater 91 to 93 is controlled independently. The outer heater 4 can be controlled to be linked with the temperature sensor 101 to 103 of any inner heater 91 to 93, or it can be controlled to calculate the average value of the three temperature sensors 101 to 103 and be linked with it. Of course, the temperature sensor 12 can also be prepared independently for the outer heater 4. Here, the case where the temperature sensor 12 is provided independently is shown. In addition, since the outer heater 4 is divided according to the outer heater block 5, the temperature sensor 12 is also prepared independently.

[0064] Next, the operation of the vaporizer A of the present invention will be described. Figure 4 The present invention is an example of the device structure of a semiconductor manufacturing device using the vaporizer A of the present invention, and the semiconductor manufacturing device is composed of the following structure: a raw material tank T, which stores a liquid raw material L (a hydrogen peroxide solution in the present embodiment) and delivers the liquid raw material L through a pressurized gas G0; a liquid flow controller E, which is connected to the raw material tank T and delivers the supplied liquid raw material L at a certain flow rate; a mass flow controller S, which is connected to an atomizing gas supply source such as nitrogen and oxygen and delivers these atomizing gases G1 at a mass flow rate; an atomizer 7, which is composed of a liquid raw material inlet pipe 7b for receiving the liquid raw material L delivered from the liquid flow controller E and a spray gas pipe 7a for receiving the atomizing gas G1 from the mass flow controller S; and a vaporizer A, which is equipped with the atomizer 7 at its inlet portion, for example, to stably supply a certain amount of vaporizing gas G2 (a water vapor gas containing hydrogen peroxide in the present embodiment) to a reaction furnace H for oxidizing a silicon substrate.

[0065] In this device A, when the heaters 4 (9) are energized, they generate heat, and in the inner tube 2, the inner heater block 3 is heated, and in the outer tube 1, the outer heater block 5 is heated.

[0066] In the inner tube 2 made of heat-resistant glass, the segments 31 to 33 of the inner heater block 3 gradually expand with the temperature rise. On the other hand, the inner tube 2 hardly expands thermally, and the inner diameter is kept substantially constant. The outer peripheral surfaces of the segments 31 to 33 are pressed against the inner peripheral surface of the inner tube 2, and the thermally expanded segments 31 to 33 expand in a direction to narrow the gap C between the facing surfaces 31m to 33m, thereby compressing the elastic material 8. In addition, the elastic force of the elastic material 8 is selected to be sufficiently weak in a range that does not damage the inner tube 2 as described above.

[0067] Then, when the heated outer heater block 5 and the inner heater block 3 heat the outer tube 1 and the inner tube 2 to a predetermined temperature, the liquid raw material L (hydrogen peroxide solution in this embodiment) is supplied to the sub-supply hole 7d of the atomizer 7, and the atomizing gas G1 is pressed into the main supply hole 7c. As a result, the liquid raw material L becomes a mist fluid K from the spray port 73 and is sprayed into the atomizing space M.

[0068] The mist fluid K collides with the spherical front end head 2a of the inner tube 2, and moves toward the outlet nozzle 11 in the gasification gap R while swirling around the inner tube 2. That is, a swirling flow is generated in the gasification gap R. Thus, the heating time can be fully ensured. During this period, when the entire gasification gap R becomes a temperature boundary layer, the swirling flow is heated to a temperature close to the wall temperature and rapidly vaporized, and becomes a gasification gas G2 and is discharged from the outlet nozzle 11 and supplied to the reactor H.

[0069] Since the entire outer peripheral surface of the split bodies 31 to 33 of the above-mentioned internal heater block 3 is in contact with the inner peripheral surface of the inner tube 2 without a gap (or, in contact via a very small amount of heat transfer paste), the heat from the split bodies 31 to 33 is efficiently transferred to the inner tube (quartz glass tube) 2. In this case, since heat transfer paste as in the past is not used in this part (even if a very small amount of heat transfer paste is used, its degradation is not an amount that hinders thermal conductivity), the temperature can be made higher than before. As a result, the vaporization efficiency of the liquid raw material L is significantly improved, and the vaporizable flow rate of the liquid raw material L is dramatically increased compared to the past. (In addition, when using a very small amount of heat transfer paste, it is preferable to set the temperature increase of the inner tube 2 to the heat resistance temperature of the heat transfer paste.)

[0070] Furthermore, when the atomizer 7, the outer tube 1, and the inner tube 2 of the vaporizer A are formed of "quartz glass", even if the liquid raw material L is a hydrogen peroxide solution, it will not be corroded, and thus it can be applied to the surface oxidation of silicon substrates.

[0071] Description of Reference Numerals

[0072] A: Vaporizer, Ah: Vaporizer body, Ak: Heating part, C: Gap, CL: Center axis, E: Liquid flow controller, G0: Pressurized gas, G1: Atomizing gas, G2: Vaporizing gas, H: Reactor, K: Mist fluid, L: Liquid raw material, M: Atomizing space, Q: Circulating fluid, R: Vaporization gap, S: Mass flow controller, T: Raw material tank, W: Width of vaporization gap, 1: Outer tube, 1a: Closed end, 2: Inner tube, 2a: Front end head, 3: Inner heater block, 4: Outer heater, 5: Outer heater block, 6: Protrusion , 7: atomizer, 7a: spray gas pipe, 7b: liquid raw material introduction pipe, 7c: main supply hole, 7d: auxiliary supply hole, 8: elastic material, 9 (91~93): internal heater, 10 (101~103): temperature sensor, 11: outlet nozzle, 12: temperature sensor, 31~3n: split body, 31m~33m: facing surface, 35: spring storage hole, 41, 42: split body of external heater, 51, 52: split body of external heater block, 73: spray port, 80: fixing belt, 101~103: temperature sensor.

Claims

1. A vaporizer, comprising an atomizer, a hollow vaporizer body, and a heating unit, wherein the atomizer atomizes and sprays a liquid raw material, the vaporizer body is connected to a spray port of the atomizer at one end, and has an outlet nozzle as an outlet of vaporized gas at the other end, the heating unit is accommodated in the vaporizer body, and is characterized in that: The heating unit is composed of: an inner tube made of heat-resistant glass, which has an outer diameter smaller than the inner diameter of the vaporizer body, and a front end head as an insertion end is closed; an inner heater block, which is inserted into the inner tube; and an inner heater, which is buried in the inner heater block. The outlet nozzle is arranged to communicate with a gasification gap formed between the inner peripheral surface of the gasifier body and the outer peripheral surface of the inner tube. The inner heater block is composed of a plurality of divided bodies divided along the central axis of the inner heater block and an elastic material. The elastic material is disposed between the split bodies and acts to press the split bodies in a separation direction and to press the outer peripheral surface of the split bodies against the inner peripheral surface of the inner tube. The internal heaters are respectively buried in the divided bodies.

2. The gasifier according to claim 1, characterized in that Heat-resistant glass is quartz glass.

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