gasifier

Abstract

The vaporizer 10 consists of a vaporizer body 20, a spherical body 30, and a heater H. The vaporizer body 20 comprises a liquid feedstock supply section 12 for supplying liquid feedstock LM, a vaporization section 22 having an internal vaporization space K for vaporizing the liquid feedstock LM, and a feedstock gas discharge section 40 for discharging the vaporized feedstock gas VG to the next process. The spherical body 30 is filled within the vaporization section 22. The heater H emits infrared radiation. The heater H is positioned with a gap d1 between it and the vaporization section 22. The vaporization section 22 and the spherical body 30 are made of transparent components capable of transmitting infrared radiation. A liquid accumulation section E for the liquid feedstock LM to flow into is provided in the vaporization section 22 at a position lower than the flow path R of the liquid feedstock LM flowing in the vaporization space K.

Description

Technical Field

[0001] This invention relates to a vaporizer capable of efficiently and stably vaporizing liquid raw materials used in semiconductor manufacturing processes. Background Technology

[0002] In semiconductor manufacturing processes, there exists a device for vaporizing liquid raw materials for film formation processes, such as oxide film or thin film formation, and supplying the vaporized raw material to the next processing unit. A vaporizer is used as a device for vaporizing liquid raw materials controlled at a certain flow rate and supplying the vaporized raw material to the next processing unit.

[0003] For example, in the oxide film formation process, in order to form an oxide film on the surface of a silicon wafer, a raw material gas for oxide film formation (specifically, an oxidizing gas such as water vapor or hydrogen peroxide vapor) is supplied into a high-temperature oxidation furnace to perform the oxide film formation process. Other examples of the use of organic compounds include TEOS (tetraethoxysilane) and its derivative PhTES (triethoxyphenylsilane).

[0004] Furthermore, in this film-forming process, the vaporizer is required to stably deliver the required flow rate of feed gas at the temperature required by the processing unit. During the film-forming process, the flow rate of the feed gas is typically varied.

[0005] In the vaporizer, the heat required for vaporization needs to be adjusted in accordance with changes in the flow rate of the liquid feedstock. Therefore, it is necessary to control the power supply to the heater.

[0006] In addition, the vaporizer is required to completely vaporize the supplied liquid feedstock and supply it to the next processing unit in a stable state. In this case, the device size must not be too large for the complete vaporization of the liquid feedstock.

[0007] As an existing vaporizer (Patent Document 1), it comprises a cylindrical metal shell extending vertically, a metal disc enclosed by the shell and having numerous micropores extending through both sides, a liquid feed nozzle perpendicularly positioned to the disc and supplying liquid feed material to the disc surface, and a heater located on the outer periphery of the shell and heating the shell and disc. In this vaporizer, liquid feed material drips from the liquid feed nozzle onto the disc surface. Due to its surface tension, the dripping liquid feed material diffuses across the disc surface and is efficiently vaporized by the heated disc. The vaporized feed gas flows downward through the micropores of the disc, accompanied by carrier gas supplied from above to the shell.

[0008] However, in this vaporizer, for example, if a liquid feedstock containing organic compounds is vaporized, the residue remaining on the surface of the disk that is not vaporized will gradually clog the numerous micropores provided on the disk. Soon after, due to the blockage, the amount of liquid feedstock that can be vaporized decreases, eventually leading to a complete failure to vaporize. In other words, if blockage occurs, the full amount of the supplied liquid feedstock cannot be accurately vaporized within a specified time, making it impossible to stably supply feedstock gas to the processing device. Therefore, the vaporizer described in Patent Document 2 has been proposed.

[0009] The vaporizer described in Patent Document 2 divides the shell of Patent Document 1 into inner and outer shells. The inner shell contains numerous opaque ceramic or corrosion-resistant metal granules, and the bottom of the inner shell has numerous orifices with diameters larger than the micropores of the disc in Patent Document 1. The portion containing the granules becomes the vaporization section for the liquid feedstock. The shell and the entire granule assembly are heated primarily through heat conduction from the heater.

[0010] Liquid feedstock is supplied as droplets from a liquid feedstock supply nozzle onto the granules, wetting the surface of the granules while flowing down into one or more streams through the gaps between the granules. As the granules are heated by the shell, the liquid feedstock flowing down while wetting the surface of the granules gradually vaporizes.

[0011] The carrier gas is supplied from above to the shell, flows downward through the gaps between the granules, and during this process, the vaporized feed gas flows downward from the holes at the bottom of the inner shell, continuing its flow toward the next processing unit. The heater is controlled so that the liquid feedstock is completely vaporized before reaching the bottom of the shell. This vaporizer eliminates the problem of clogging of the micropores in the vaporizer described in Patent Document 1 by using granules as the vaporization layer and making the bottom holes larger than the micropores in Patent Document 1.

[0012] Existing technical documents

[0013] Patent documents

[0014] Patent Document 1: US Patent No. 5,711,816

[0015] Patent Document 2: Japanese Patent Application Publication No. 2001-295050 Summary of the Invention

[0016] The problem that the invention aims to solve

[0017] In the vaporizer described in Patent Document 2, the vaporization section is made of an opaque sphere and the bottom hole is made larger than the micropore of Patent Document 1, thereby eliminating the blockage of the vaporizer described in Patent Document 1. However, it has the problem of not being able to flexibly cope with the increase or decrease of liquid raw materials.

[0018] That is, the vaporizer, as described above, has an opaque spherical vaporization section, causing the supplied liquid feedstock to completely vaporize during its flow. However, if the supply of liquid feedstock increases excessively relative to the heat output of the heater, unvaporized liquid feedstock will leak out from the bottom hole as is. The presence of unvaporized liquid results in poor film formation.

[0019] Conversely, if the vaporization section is designed to match the supply of liquid feedstock, its size must be determined by the maximum supply, potentially making the vaporizer itself too large. Conversely, if the shape of the vaporizer is restricted, the maximum supply of liquid feedstock must be limited.

[0020] In other words, the vaporizer in Patent Document 2 cannot achieve the vaporization of a large amount of liquid raw materials, and it is difficult to flexibly respond to changes in the required gas volume.

[0021] In addition, thermocouples are typically installed in the housing for heater temperature regulation. However, the liquid feedstock in laminar flow under spherical conditions flows in one or more streams. If a thermocouple is placed near a low-temperature liquid feedstock stream, the detected temperature will be lower, causing the heater to overheat. As a result, the temperature of the feed gas supplied to the processing unit becomes higher than the required temperature, which also has an adverse effect on the liquid feedstock.

[0022] Furthermore, in the vaporizer of Patent Document 2, the opaque spherical bodies are heated primarily through heat conduction via the inner shell. Therefore, the peripheral portion of the spherical body in contact with the inner shell becomes hotter than the inner shell, while the central portion remains cold due to poor heat transfer, resulting in uneven temperature distribution. As described above, the flow path of the liquid feedstock through the spherical layer is not constant; some flows through the central portion, while others flow through the peripheral portion, causing the vaporization state to vary depending on the flow path of the liquid feedstock. This variation hinders the stable supply of the feedstock gas to the next processing unit.

[0023] The present invention was made in view of the aforementioned existing problems. The first objective is to provide a vaporizer capable of flexibly supplying raw material gas in response to changes in the required amount of raw material gas in the processing device, capable of completely vaporizing the supplied liquid raw material without causing blockage and without producing unvaporized liquid raw material, and capable of stably supplying the raw material gas to the processing device at the required temperature. Furthermore, the second objective is to provide a vaporizer that accurately measures the temperature of the heater in order to solve the first objective.

[0024] Technical means for solving problems

[0025] To solve the above-mentioned problems, the present invention (Solution 1) configures the vaporizer 10 as follows.

[0026] A vaporizer 10 comprises a vaporizer body 20, a spherical body 30, and a heater H.

[0027] The vaporizer body 20 consists of a liquid raw material supply section 12 for supplying liquid raw material LM for semiconductor manufacturing, a vaporization section 22 having a vaporization space K inside for vaporizing the supplied liquid raw material LM, and a raw material gas discharge section 40 for sending the vaporized raw material gas VG to the next process.

[0028] The spherical body 30 is filled inside the vaporization section 22.

[0029] The heater H emits infrared rays to vaporize the liquid raw material LM.

[0030] The vaporizer 10 is characterized in that it is configured such that,

[0031] The heater H is disposed with a gap d1 of width M1 between it and the vaporization section 22.

[0032] The vaporization section 22 and the spherical body 30 are made of transparent components that allow infrared light to pass through.

[0033] At a position lower than the flow path R of the liquid raw material LM flowing in the gasification space K, a liquid accumulation section E is provided in the gasification section 22 for the liquid raw material LM to flow into.

[0034] Option 2 is based on the vaporizer 10 of Option 1, wherein the vaporizer 10 is characterized in that the vaporization section 22 is composed of bent tubing.

[0035] Scheme 3 is based on vaporizer 10 of Scheme 1. Vaporizer 10 is characterized by including a reflective component 28, which is arranged outside the heater H in a manner surrounding the vaporization section 22, and the inner surface opposite to the vaporization section 22 is formed as a mirror 28k that reflects infrared light.

[0036] Option 4 involves installing an auxiliary reflector component 89 in heater H. Figure 3 , Figure 5 ).

[0037] Based on the vaporizer 10 described in scheme 1 or 3, the vaporizer 10 is characterized in that an auxiliary reflective component 89 is disposed on the surface of the heater H opposite to the vaporizer body 20, and the surface of the auxiliary reflective component 89 that reflects infrared rays toward the vaporizer body 20 is a mirror surface 89k.

[0038] Option 5 involves a temperature detector 70 ( Figure 2 Configuration of ).

[0039] Based on the vaporizer 10 described in scheme 1 or 3, the vaporizer 10 is characterized in that,

[0040] A temperature detector 70 for measuring infrared radiation is configured with a gap d2, d3 of width M2, M3 between the vaporization section 22 and the heater H relative to the vaporizer body 20 and the heater H.

[0041] Option 6 involves a temperature detector 70 ( Figure 2 The specific structure of ).

[0042] Based on the vaporizer 10 described in Scheme 5, the vaporizer 10 is characterized in that,

[0043] The temperature detector 70 consists of a graphite infrared absorber 78 that absorbs infrared rays and is heated, and a temperature detection element 71 embedded in the infrared absorber 78 and detecting the temperature of the infrared absorber 78.

[0044] Invention Effects

[0045] According to the present invention (Solution 1), since the vaporization section 22 and the spheres 30 are made of transparent components that allow infrared light to pass through, the infrared light emitted from the heater H passes through them as a whole. As a result, the liquid raw material LM supplied to the vaporization section 22 is uniformly and directly heated by infrared light during its flow down between the spheres 30, regardless of the flow path R it takes.

[0046] Furthermore, in the vaporization section 22, a liquid accumulation section E is provided at a position lower than the flow path R of the liquid raw material LM flowing in the vaporization space K. If the supply quantity of liquid raw material LM from the liquid raw material supply section 12 is large and it is not completely vaporized before reaching the liquid accumulation section E, the unvaporized liquid raw material LM will accumulate in the liquid accumulation section E. The unvaporized liquid raw material LM accumulated in the liquid accumulation section E is heated therein and vaporized efficiently in sequence, preventing leakage from the liquid accumulation section E.

[0047] Therefore, it can efficiently process large quantities of liquid feedstock LM with a small-capacity vaporization unit 22, and can flexibly respond to changes in the supply of liquid feedstock LM.

[0048] In the present invention (Solution 2), since the vaporization section 22 is made of a bent pipe, the bent portion 22e becomes the liquid accumulation section E, and the vaporizer 10 can flexibly respond to changes in the supply of liquid raw material LM.

[0049] According to the present invention (Solution 3), since the infrared rays emitted from the heater H are repeatedly reflected in numerous and random directions by the reflective member 28 surrounding the vaporization section 22, the transparent vaporizer body 20 and the spherical body 30 are uniformly irradiated with infrared rays throughout. Furthermore, the liquid raw material LM that flows out in streams through the gaps in the transparent spherical body 30 is smoothly vaporized mainly through the efficient absorption of infrared rays.

[0050] According to the present invention (Scheme 4), infrared rays emitted from the heater H to the opposite side of the vaporizer body 20 are reflected by the auxiliary reflector 89 toward the vaporizer body 20, and correspondingly, the infrared rays emitted from the heater H are concentrated toward the vaporizer body 20.

[0051] According to the present invention (Solution 5), since the temperature detector 70 is arranged in a non-contact manner relative to the vaporization section 22 and the heater H, the temperature detector 70 can perform temperature detection without being affected by the vaporization section 22 or the heater H. The temperature detection of the temperature detector 70 depends only on the infrared light absorbed by the temperature detector 70, thus improving the accuracy of temperature detection.

[0052] According to the present invention (Solution 6), since graphite with high absorption rate and high thermal conductivity for infrared radiation is used as the infrared absorber 78 of the temperature detector 70, the infrared radiation incident on the infrared absorber 78 is substantially absorbed and heat is transferred, and the amount of infrared radiation from the heater H can be accurately and quickly measured. Attached Figure Description

[0053] Figure 1 This is a longitudinal sectional view of the vaporizer of the present invention (Embodiment 1) viewed from the front.

[0054] Figure 2 yes Figure 3 Sectional view A-A' in the middle.

[0055] Figure 3 yes Figure 1 Sectional view B-B' in the diagram.

[0056] Figure 4 (a) is a longitudinal sectional view of the heater used in the vaporizer of the present invention, and (b) is a partial longitudinal sectional view of another heater.

[0057] Figure 5 (a) is a top view of the heater, and (b) is... Figure 4 (a) is the C-C' section view.

[0058] Figure 6 (a) is a longitudinal sectional view of the temperature detector used in the vaporizer of the present invention, and (b) is a top view.

[0059] Figure 7(a) is a partial enlarged view of the gap between the temperature detector and the vaporizer body and the heater, and (b) is a partial enlarged view of the gap between the vaporizer body and the heater.

[0060] Figure 8 (a) is a partially enlarged sectional view of the straight section of the gasification unit, and (b) is a partially enlarged sectional view of the bent section.

[0061] Figure 9 This is a partial longitudinal sectional view of another example of the liquid supply section of the vaporizer of the present invention.

[0062] Figure 10 This is a longitudinal sectional view of Embodiment 2 of the vaporizer of the present invention.

[0063] Figure 11 yes Figure 10 The D-D' section view in the diagram.

[0064] Figure 12 This is a longitudinal sectional view of a third embodiment of the vaporizer body of the present invention.

[0065] Figure 13 This is a longitudinal sectional view of the fourth embodiment of the vaporizer body of the present invention.

[0066] Figure 14 This is a longitudinal sectional view of embodiment five of the vaporizer body of the present invention.

[0067] Figure 15 This is a longitudinal sectional view of Embodiment Six of the vaporizer body of the present invention. Detailed Implementation

[0068] The present invention will now be described with reference to the accompanying drawings. The vaporizer 10 is a device that vaporizes liquid raw material LM supplied from the upstream side into raw material gas VG and supplies it to various semiconductor manufacturing apparatuses downstream of which the raw material gas VG is used.

[0069] The vaporizer 10 is generally composed of a vaporizer body 20, a heater H, a temperature detector 70, and a reflective component 28 that functions as a housing to house them.

[0070] As described above, there are various liquid raw materials (LM), which are appropriately selected according to the raw material gas (VG) used in various semiconductor manufacturing equipment. Here, water, hydrogen peroxide, or TEOS (tetraethoxysilane) and PhTES (triethoxyphenylsilane) are examples of representative liquid raw materials.

[0071] These liquid feedstock LMs efficiently absorb mid-infrared light in the wavelength range of 2.5 μm to 4 μm. In the case of water, when the film thickness is 10 μm or more, it efficiently absorbs mid-infrared light in the above range. When the film thickness is 1 mm, it absorbs almost 100% of the mid-infrared light in the above range.

[0072] The liquid feedstock LM is supplied to the vaporizer body 20 in the form of atomization, droplets, or liquid. Sometimes the carrier gas CG is supplied to the vaporizer body 20 together with the liquid feedstock LM, and sometimes only the liquid feedstock LM is supplied to the vaporizer body 20 without the carrier gas CG. When the liquid feedstock LM is supplied to the vaporizer body 20 in the form of atomization, a device such as a sprayer 12a is used. Figure 9 ).

[0073] The vaporizer body 20 has various structures to solve the above-mentioned problems, and is characterized in that a liquid accumulation section E for the liquid raw material LM to flow into is provided in the vaporization section 22 at a position lower than the flow path R of the liquid raw material LM flowing in the vaporization space K.

[0074] (Implementation Method 1:) Figures 1-8 )

[0075] In the vaporizer 10 of Embodiment 1, liquid raw material LM is supplied to the vaporizer body 20 in a liquid or droplet form. The vaporizer body 20 consists of a liquid raw material supply section 12 that supplies liquid raw material LM to the vaporization space K, a vaporization section 22 that has a vaporization space K inside which the supplied liquid raw material LM is vaporized, and a raw material gas discharge section 40 that sends the vaporized raw material gas VG to the next process.

[0076] Figure 1 In the case of liquid raw material supply section 12, raw material gas discharge section 40, and vaporization section 22, the vaporizer body 20 is integrated. Of course, there are also cases where, as described later, the liquid raw material supply section 12, raw material gas discharge section 40, and vaporization section 22 are separate units. Figure 9 ).

[0077] The vaporizer body 20 is a component that transmits infrared light, for example, by bending a circular tube made of transparent quartz glass.

[0078] In this embodiment, the vaporization section 22 is a U-shaped bend, consisting of a bend 22e and straight pipe sections 22f and 22g extending upward from the bend 22e.

[0079] The liquid raw material supply section 12 is integrally connected to one of the straight pipe sections 22f, forming an inverted L-shape, with the inlet portion extending horizontally. The raw material gas discharge section 40 is integrally connected to the other straight pipe section 22g, with the outlet portion extending horizontally.

[0080] The vaporization section 22, which is U-shaped and consists of bent portions 22e and straight tube portions 22f and 22g, is filled with spherical bodies 30 that are transmissive to infrared light, for example, made of transparent quartz. The spherical bodies 30 are, for example, spheres with a diameter of 2 mm to 5 mm.

[0081] Inside the vaporization section 22, the portion filled with spherical bodies 30 is the vaporization space K.

[0082] The spherical bodies 30 are connected to each other in a point-contact manner, and a gap P is formed between the spherical surfaces of the spherical bodies 30 to form a flow path for the liquid raw material LM.

[0083] exist Figure 1 In this embodiment, the vaporization section 22 is U-shaped. However, the shape of the vaporization section 22 is not limited to a U-shape, as will be described later. The bent portion 22e constituting the bottom of the vaporization section 22 becomes the liquid accumulation section E of the liquid raw material LM. In this invention, the liquid accumulation section E can be located at a position lower than the flow path R of the liquid raw material LM flowing in the vaporization space K, including, for example, an example described later, where the bent portion 22e is provided below the horizontally extending straight pipe portions 22f and 22g. Figure 12 ), roughly n-shaped scheme ( Figure 13 ), a W-shaped scheme ( Figure 14 A scheme like a helical tube arranged in a horizontal direction ( Figure 15 ).

[0084] Porous filters 23f and 23g are provided on the spherical bodies 30 filling the straight tube portions 22f and 22g, as needed. The materials of the porous filters 23f and 23g are not limited, as long as they can allow the liquid raw material LM to pass through smoothly without being impaired. Here, a porous, semi-molten quartz glass material is used, capable of transmitting infrared rays emitted from the heater H and welded to the vaporizer body 20, whereby the contact portion of the quartz glass powder is fused together in a semi-molten state.

[0085] Furthermore, although not shown in the figure, in order to maintain the discharged raw material gas VG at a certain temperature, a cylindrical heater block with a built-in heater can be installed on the outer periphery of the tubular raw material gas discharge section 40.

[0086] The reason for using transparent quartz glass as the material for the vaporizer body 20 and the spherical body 30 is that it can transmit infrared rays emitted from the heater H, and the infrared rays can be transmitted to the center of the vaporization section 22.

[0087] In this embodiment, the spherical body 30 is spherical, but not limited to spheres; it could also be, for example, granular quartz. Since the surface area is increased in this case, it is preferable in terms of improving the gasification efficiency of the liquid feedstock. However, a shape that would break under vibration or other external forces, resulting in particles, is not used.

[0088] On both sides of the vaporizer body 20, multiple heaters H (two on each side in this embodiment) are erected. Preferably, the straight pipe portions 22f and 22g of the vaporization section 22 are parallel to the heaters H, and the centerline of the heaters H is aligned with and parallel to the centerlines of the straight pipe portions 22f and 22g. The heaters H at least cover the straight pipe portions 22f and 22g and the bent portion 22e of the vaporization section 22, and are configured to radiate infrared rays to them equally.

[0089] A gap d1 of width M1 is provided between each heater H and the side wall 22h of the vaporizer body 20. This blocks heat transfer from the heater H to the vaporizer body 20. However, since gas (air) exists in this gap d1, heat from the heater H will be transferred to the vaporizer body 20. Therefore, it is considered that the gap d1 is used as a flow path for gas replacement, as will be described later.

[0090] The first embodiment of heater H is as follows Figure 4 As shown in (a), the heater H consists of two pairs of transparent quartz tubes 80, closed insulators 82 and 83 at both ends of the transparent quartz tubes 80, a connecting terminal 85 on the upper closed insulator 82, a heater coil 88 stretched inside the transparent quartz tubes 80, and an auxiliary reflector 89. The heater coils 88 are, for example, made of Kantal wire. The pair of heater coils 88 are connected within the lower closed insulator 83. The upper ends of the heater coils 88 are connected to the connecting terminal 85. An inactive gas is sealed inside the transparent quartz tubes 80.

[0091] When the heater coil 88 is a Kanthal wire, its peak wavelength is 2.6 μm. The Kanthal wire has a specific emission output of more than 50% in the mid-infrared region of approximately 1.5 μm to 4 μm.

[0092] The second embodiment of heater H is shown in Figure 4 (b) In this case, the heater coil 88 is formed of graphite that has been processed into a serrated shape. In the case of graphite, it also emits infrared radiation similar to that of the Kanthal rays.

[0093] exist Figure 5 Example of using an auxiliary reflective element 89 is shown in heater H (b). Since the main reflective element 28 surrounds the vaporizer body 20 as described later, this auxiliary reflective element 89 is not necessary. The auxiliary reflective element 89 is disposed on the back side of the transparent quartz tube 80, i.e., the surface opposite to the side wall 22h of the vaporizer body 20. The surface of the auxiliary reflective element 89 opposite to the vaporizer body 20 is called a mirror surface 89k.

[0094] The reflective component 28 is a cylindrical component designed to reflect infrared rays emitted from the heater H toward the vaporization space K. The inner surface of the reflective component 28 is precision-machined into a mirror surface 28k by means of plating or vapor deposition with a metal with high infrared reflectivity (such as gold), or by attaching aluminum foil to form a mirror surface 28k.

[0095] Reflective component 28, such as Figure 3 It is thus arranged outside the heater H in a manner that surrounds the vaporizer body 20. A top panel 21 is mounted on the upper end of the reflector 28, and a bottom panel 27 is mounted on its lower end. The inner surfaces of the top panel 21 and the bottom panel 27 also serve as mirror surfaces 28k.

[0096] A hole is provided in the bottom panel 27, which serves as a displacement gas supply section 25. A hole is also provided in the top panel 21, which serves as a displacement gas exhaust section 26. Through these holes, the displacement gas (air) flows within the internal space of the reflector 28, where the heater H is located. As a result, the surrounding gas (air) heated by the heater H rises and is discharged from the displacement gas exhaust section 26. Instead, ambient air at room temperature flows in from the displacement gas supply section 25, and the space where the heater H is located is maintained at the temperature of the displacement gas (air). As a result, as will be described later, most of the thermal influence of the heater H on the vaporizer body 20 and the temperature detector 70 within the internal space of the reflector 28 is eliminated.

[0097] exist Figures 1-3 The diagram illustrates an example of thermal movement towards the vaporizer body 20 within a space equipped with a heater H. When the heater H heats the gas (air), the temperature of the surrounding gas rises. The sidewalls 22h of the vaporizer body 20 are heated via this heated gas (air). Therefore, the width M1 of the gap d1 is studied, and the gap d1 is used as a flow path for the displacement gas. This is applicable to all embodiments.

[0098] In this case, the width M1 of the aforementioned gap d1 becomes a problem. As described above, the room-temperature outside gas flowing in from the displacement gas supply section 25 rises along the heater H and gradually heats up. When the distance between the heater H and the side wall 22h of the vaporizer body 20 (width M1) is close and smaller than the thickness δ of the temperature boundary layer T, the displacement gas flowing along the heater H and heated by the heater H will come into contact with the side wall 22h of the vaporizer body 20. As a result, the temperature of the side wall 22h will be affected by the heater H.

[0099] Therefore, as Figure 7 As shown in (b), when the width M1 between the heater H and the sidewall 22h of the vaporizer body 20 is greater than the thickness δ of the temperature boundary layer T, the unheated displacement gas flows along the sidewall 22h between the heated temperature boundary layer T and the sidewall 22h, thus blocking the thermal influence of the heated temperature boundary layer T. Therefore, the influence of the heated temperature boundary layer T within the space where the heater H is located is effectively eliminated.

[0100] The temperature detector 70 comprises a temperature sensing element 71 and an infrared absorber 78. The temperature sensing element 71 is formed by embedding a pair of thermocouple wires 71a and 71b, which serve as the temperature sensing element 71, within an insulating layer 72 in a stainless steel sheath 74. In this embodiment, the sheath-shaped infrared absorber 78 is wrapped around the junction 73 of the thermocouple wires 71a and 71b and is tightly fitted to the sheath 74. Graphite, which has superior thermal conductivity than metal, is used as the infrared absorber 78. A thinner infrared absorber 78 is preferred to be more sensitive to changes in absorbed infrared radiation.

[0101] like Figure 2 As shown, the temperature detector 70 is configured with gaps d2 and d3 of widths M2 and M3 between the vaporizer body 20 and the heater H in a non-contact manner relative to the vaporizer body 20 and the heater H.

[0102] In the straight pipe section 22f at the inlet side of the vaporizer body 20, especially the vaporization section 22, the liquid feedstock LM, after passing through the porous filter 23f, flows as one or more meandering streams (flow paths R) between the spheres 30. When the heat from the infrared radiation from the heater H is sufficient for the liquid feedstock LM, all the liquid feedstock LM in the straight pipe section 22f at the inlet side is vaporized. Conversely, when the heat from the infrared radiation from the heater H is insufficient for the liquid feedstock LM, not all the liquid feedstock LM in the straight pipe section 22f at the inlet side is vaporized, and the unvaporized liquid feedstock LM accumulates in the bend section 22e.

[0103] Since the part through which the liquid raw material LM flows and accumulates has a lower temperature compared to other parts, if a temperature detector 70 is installed in this part, the detected temperature will be lower.

[0104] If the temperature detector 70 is set in a non-contact manner relative to the vaporizer body 20 and the heater H, it will not be affected by either, absorb infrared radiation from the heater H and be heated, and detect the amount of infrared radiation from the heater H.

[0105] Strictly speaking, the widths M2 and M3 of the gaps d2 and d3 become a problem. As described above, the reflector 28 draws the vaporizer body 20 and heater H into its interior. The internal temperature of the reflector 28 and the temperature of the side wall 22h of the vaporizer body 20 gradually increase along the heater H. Even if, as described above, low-temperature outside gas flows into the reflector 28 from the displacement gas supply section 25, passes through the gaps d2 and d3, and exits from the displacement gas discharge section 26 on the top surface, similarly, when the widths M2 and M3 between the infrared absorber 78 of the temperature detector 70 and the heater H and the side wall 22h of the vaporizer body 20 are close to and less than the thickness δ of the temperature boundary layer T, the heated displacement gas will come into contact with the infrared absorber 78. As a result, the temperature measurement of the temperature detector 70 will be affected.

[0106] like Figure 7 As shown in (a), when the gaps d2 and d3 (widths M2 and M3) are greater than the thickness δ of the temperature boundary layer T, the displacement gas that has not been heated flows along the infrared absorber 78 between the heated temperature boundary layer T and the infrared absorber 78, which will block the thermal effect of the heated temperature boundary layer T for the temperature detector 70.

[0107] This effectively eliminates the influence of the temperature boundary layer T after heating within the space containing the infrared absorber 78. As a result, accurate temperature measurement of the heater H can be achieved.

[0108] Furthermore, as described above, the heater coil 88 of the heater H is covered by a transparent quartz tube 80, making it impossible to place the temperature detector 70 on the heater coil 88. If the temperature detector 70 were placed on the transparent quartz tube 80, it would damage the transparent quartz tube 80, therefore the temperature detector 70 cannot be placed on the transparent quartz tube 80.

[0109] Temperature detector 70 is connected to an external infrared heater temperature controller 90. Infrared heater temperature controller 90 is connected to power supply 91 and controls the power supply to heater H according to the output from temperature detector 70.

[0110] Next, a method for vaporizing liquid feedstock LM using the vaporizer 10 of the present invention will be described. When the heater H is energized, mid-infrared rays containing a region of about 1.5 μm to 4 μm with a peak wavelength of 2.6 μm are radially emitted from the heater coil 88, forming a mountain-shaped infrared ray that expands toward the short wavelength side and the long wavelength side.

[0111] On the side of heater H facing the vaporizer body 20, a significant portion of the infrared radiation travels toward the vaporizer body 20. The infrared radiation exiting to the rear side is reflected by the auxiliary reflector 89 on the back of heater H (or by the cylindrical main reflector 28 in the absence of the auxiliary reflector 89) and travels toward the vaporizer body 20.

[0112] Since the vaporizer body 20 is formed of transparent quartz glass that allows infrared light to pass through, infrared light traveling toward the vaporizer body 20 is refracted and transmitted through the sidewall 22h of the vaporizer body 20. Because the interior of the vaporizer body 20 is filled with spherical bodies 30, infrared light reaching the vaporization space K inside the vaporizer body 20 is refracted and transmitted through these spherical bodies 30 and reaches the opposite sidewall 22h, where it is further refracted and transmitted through the sidewall 22h. To avoid complicating the accompanying drawings, infrared light is shown as a straight line.

[0113] Most of the infrared radiation transmitted through the vaporizer body 20 is reflected by the mirror 28k on the opposite side of the cylindrical reflector 28 and then transmitted through the vaporizer body 20 again. The remaining infrared radiation is reflected by the auxiliary reflector 89. The infrared radiation repeats this process instantaneously and infinitely within the cylindrical reflector 28.

[0114] The infrared radiation within the vaporization space K of the vaporizer body 20 is reflected instantaneously and infinitely as described above, thus resulting in uniformity. When the vaporization space K heats up to a uniform temperature at a set point and reaches a vaporizable state for the liquid feedstock LM, the liquid feedstock LM is supplied to the liquid feedstock supply section 12. The liquid feedstock LM flows through the liquid feedstock supply section 12 and down onto the porous filter 23f on the inlet side. The flowing liquid feedstock LM seeps into the porous filter 23f and exits from its lower surface. The spherical body 30 is in contact with the lower surface of the porous filter 23f, and the seeping liquid feedstock LM flows through the surface of the spherical body 30 in one or more streams (flow path R) and randomly flows down.

[0115] Regarding the spheres 30, adjacent spheres 30 are in point contact with each other and support each other, forming a gap P between them that is roughly triangular in plan view and is composed of complex concave spherical surfaces. Figure 8(a) Most of the liquid feedstock LM flows down while wetting the surface of the spherical body 30, and the remaining liquid feedstock LM accumulates in the pores P due to the surface tension of the liquid feedstock LM, forming a liquid film of the liquid feedstock LM. When the film thickness of the liquid feedstock LM is 10 μm or more, it efficiently absorbs mid-infrared radiation in the range of 2.5 μm to 4 μm. In particular, when the film thickness is 1 mm or more, it absorbs almost 100% of the mid-infrared radiation.

[0116] The infrared radiation used here is mostly mid-infrared, with wavelengths of 2.5 μm to 4 μm as described above, including the absorption peak wavelength (3 μm) of the liquid material LM. Therefore, a portion of the mid-infrared radiation reaching the vaporization section 22 is absorbed by the thin film of the liquid material LM formed on the surface of the sphere 30, or absorbed by the liquid film of the liquid material LM accumulated in the voids P, becoming heat and causing the liquid material LM to vaporize. If the film thickness of the liquid material LM is too thin, the infrared radiation is transmitted as is. Since the sphere 30 is formed of transparent quartz glass that allows infrared radiation to pass through, the infrared radiation not absorbed by the liquid material LM passes through the sphere 30 and emerges on the opposite side.

[0117] Infrared rays not absorbed by the liquid feedstock LM are transmitted through the spherical body 30 filled within the vaporizer body 20, and then through the sidewall 22h on the opposite side of the vaporizer body 20 before exiting outwards. The infrared rays emitted from the vaporizer body 20 are reflected by the mirror 28k on the opposite side of the reflecting member 28 (or a portion thereof is reflected by the auxiliary reflecting member 89) and return to the vaporizer body 20. In this way, the liquid feedstock LM flowing down in the vaporization space K (i.e., the straight pipe portion 22f on the inlet side) is mainly heated by uniform mid-infrared rays, and the liquid feedstock LM, after absorbing these mid-infrared rays and heating up, gradually vaporizes. On the other hand, the heating of the liquid feedstock LM is relatively small due to heat transfer from the spherical body 30 based on point contact.

[0118] When the supply of liquid raw material LM is low, as described above, the liquid raw material LM is completely vaporized in the straight pipe section 22f on the inlet side before reaching the bend section 22e. The volume of the vaporized raw material gas VG increases sharply, passes through the bend section 22e and the straight pipe section 22g on the outlet side, and is discharged from the raw material gas discharge section 40 toward the next process.

[0119] When the supply of liquid feedstock LM is excessive, or when the supply of liquid feedstock LM fluctuates during the vaporization process and exceeds the heat supplied by heater H, the liquid feedstock LM will not be completely vaporized in the straight pipe section 22f on the inlet side. The remaining unvaporized liquid feedstock LM accumulates in the bend section 22e. This section is designated as the liquid accumulation section E.

[0120] The liquid feedstock LM accumulated in the liquid accumulation section E is heated by infrared irradiation and vaporizes within the narrow gap P between the spherical bodies 30. On the other hand, the unvaporized liquid feedstock LM continues to flow into the bend section 22e. Due to the presence of the liquid accumulation section E, there is no leakage of unvaporized liquid feedstock LM, enabling efficient and rapid continuous vaporization.

[0121] Furthermore, there is a straight pipe section 22g on the outlet side between the liquid accumulation section E and the outlet 40d of the vaporizer body 20, so the raw material gas VG rising from the liquid accumulation section E is uniformly heated in this section regardless of its quantity.

[0122] Next, the temperature measurement will be explained. As described above, the liquid raw material LM flowing down through the surface of the spherical body 30 gradually vaporizes and becomes one or more liquid streams flowing down within the straight pipe section 22f on the inlet side. When the flow rate is large and the liquid raw material LM accumulates in the liquid accumulation section E, which is the bend section 22e, the temperature of this section is lower than that of the spherical body 30 and the bend section 22e. Therefore, the temperature of the part where the liquid raw material LM is in contact with the bend section naturally becomes lower than that of the part where it is not in contact with the bend section. That is, temperature unevenness occurs in the straight pipe section 22f and the bend section 22e on the inlet side.

[0123] Since the temperature detector 70 is kept in a non-contact position relative to the vaporization section 22 and the heater H (at least a distance above the temperature boundary layer δ), it is not affected by temperature unevenness from the heater H.

[0124] Furthermore, the temperature detector 70 has a graphite infrared absorber 78 as a sheath-like outer layer, so the infrared rays incident on the infrared absorber 78 are essentially absorbed and converted into heat, and the infrared absorber 78 is used for temperature detection. Since the amount of infrared rays absorbed is proportional to the amount of infrared rays emitted by the heater H, if the temperature of the infrared absorber 78 is measured, the amount of infrared rays emitted by the heater H can be accurately measured.

[0125] In other words, since the temperature detection of this temperature detector 70 does not depend on heat transfer, but only on the infrared radiation absorbed by the infrared absorber 78, it is not affected by the temperature unevenness of the vaporization section 22 or the heater H, and can achieve accurate temperature measurement. In addition, if the thickness of the infrared absorber 78 is made as thin as possible, the heat transfer to the joint 73 of the temperature detector 70 becomes rapid, and the responsiveness of temperature control is improved.

[0126] (A variation of implementation method one:) Figure 9 )

[0127] The above describes an example where the liquid feedstock LM is supplied to the vaporizer body 20 as is, but sometimes it is supplied as a mist. In this case, the main part of the liquid feedstock supply section 12 is composed of an atomizer 12a. A liquid feedstock supply pipe 12b is provided at the center of the atomizer 12a, and its front end narrows into a conical shape to form a spray nozzle 12d. A carrier gas supply pipe 12c is provided on the side of the atomizer 12a. A carrier gas supply path 12e, which is connected to the spray nozzle 12d and exerts a Venturi effect, is provided on the outer periphery of the liquid feedstock supply pipe 12b. The space from the spray nozzle 12d to the porous filter 23f on the inlet side is called the atomization space S. The atomization space S is not filled with spherical bodies 30.

[0128] When liquid raw material LM is supplied to liquid raw material supply pipe 12b and carrier gas CG is supplied to carrier gas supply pipe 12c, a Venturi effect is generated, causing the liquid raw material LM from spray nozzle 12d to become a mist and be evenly distributed within the atomizing space S. The mist-like liquid raw material LM distributed within the atomizing space S is evenly injected onto the porous filter 23f and flows down in one or more streams towards the spherical body 30. The subsequent process is the same as in Embodiment 1.

[0129] (Implementation Method 2:) Figure 10 , Figure 11 )

[0130] Compared with the first embodiment, the second embodiment differs in the shape of the vaporizer body 20 and the reflector 28, and the position of the heater H relative to the vaporizer body 20.

[0131] exist Figure 3 In the first embodiment, heaters H are erected at the front and rear of the vaporizer body 20. In contrast, in this modified embodiment, heaters H are erected on both sides of the vaporizer body 20. This reduces the front-to-back width of the vaporizer 10, allowing the reflective member 28 to form a rectangular shape with a thin front-to-back width in its horizontal cross-section, thus enabling a thinner vaporizer 10. Along with this modification, the liquid feedstock supply section 12 and the feedstock gas discharge section 40, connected to the straight pipe sections 22f and 22g, extend upwards beyond the top panel 21 as before. A temperature detector 70 is disposed between the straight pipe sections 22f and 22g on the inlet or outlet side and one of the heaters H. Everything else is the same as in the first embodiment.

[0132] (Implementation Method 3:) Figure 12 )

[0133] In Embodiment 3, the vaporizer body 20 has a bent portion 22e located below the horizontally extending straight pipe portions 22f and 22g. Liquid feedstock LM flowing through the gap P of the spherical body 30 in the straight pipe portion 22f on the inlet side flows into the liquid accumulation section E, which is the bent portion 22e, when the flow rate is high. There, it is heated and vaporized. This is the same as in Embodiment 1.

[0134] In addition, Figure 12 In the second embodiment, the bent portion 22e is formed into a small U-shape. However, the second embodiment is not limited to this shape. Alternatively, the straight pipe portions 22f and 22g may be connected, and the lower surface of their boundary portion may bulge downward in a hemispherical shape, with this bulging portion serving as the liquid accumulation section E. Excess liquid raw material LM flowing in from the straight pipe portion 22f on the inlet side is accumulated in this liquid accumulation section E.

[0135] (Implementation methods four and five:) Figure 13 , Figure 14 )

[0136] In Embodiment 4, the vaporizer body 20 is formed by bending a transparent quartz tube into an approximately n-shape, while in Embodiment 5, the vaporizer body 20 is formed by bending a transparent quartz tube into a W-shape.

[0137] In this case, the path from the liquid accumulation section E to the outlet 40d can be longer than in Embodiment 1, thus further promoting uniform heating of the feed gas VG. Everything else is the same as in Embodiment 1.

[0138] (Implementation Method Six:) Figure 15 )

[0139] In Embodiment Six, the vaporizer body 20 is formed by bending a transparent quartz tube into a spiral shape, with the spiral portion arranged horizontally and a heater H positioned at its center. In this case, multiple bends 22e are also provided in the spiral portion, which further promotes uniform heating of the feed gas VG. In this case, the liquid accumulation section E becomes the initial bend 22e. In this case, the path from the liquid accumulation section E to the outlet 40d can be made longer than in Embodiment One, thus further promoting uniform heating of the feed gas VG. Everything else is the same as in Embodiment One.

[0140] Explanation of reference numerals in the attached figures

[0141] CG: Carrier gas, d1, d2, d3: Gap, E: Liquid accumulation section, H: Heater, K: Vaporization space, LM: Liquid feedstock, M1, M2, M3: Gap width, P: Void, R: Flow path, S: Atomization space, T: Temperature boundary layer, VG: Feed gas, δ: Temperature boundary layer thickness.

[0142] 10: Vaporizer; 12: Liquid feedstock supply section; 12a: Sprayer; 12b: Liquid feedstock supply pipe; 12c: Carrier gas supply pipe; 12e: Carrier gas supply path; 12d: Spray nozzle; 20: Vaporizer body; 21: Top panel; 22: Vaporization section; 22e: Bending section; 22f, 22g: Straight pipe section; 22h: Side wall; 23f, 23g: Porous filter; 25: Replacement gas supply section; 26: Replacement gas discharge section; 27: Bottom panel; 28: Reflector. Components: 28k: mirror, 30: sphere, 40: raw material gas discharge section, 40d: outlet, 70: temperature detector, 71: temperature detection element, 71a, 71b: thermocouple wire, 72: insulation layer, 73: joint, 74: sheath, 78: infrared absorber, 80: transparent quartz tube, 82, 83: enclosed insulator, 85: connecting terminal, 88: heater coil, 89: auxiliary reflector, 89k: mirror, 90: infrared heater temperature controller, 91: power supply.

Claims

1. A vaporizer 10, comprising a vaporizer body 20, a spherical body 30, and a heater H, wherein the vaporizer body 20 comprises a liquid raw material supply section 12 for supplying liquid raw material LM for semiconductor manufacturing, a vaporization section 22 having an internal vaporization space K for vaporizing the supplied liquid raw material LM, and a raw material gas discharge section 40 for discharging the vaporized raw material gas VG to the next process, the spherical body 30 being filled within the vaporization section 22, and the heater H emitting infrared rays to vaporize the liquid raw material LM. Its features are, Composed of, The heater H is disposed with a gap d1 of width M1 between it and the vaporization section 22. The vaporization section 22 and the spherical body 30 are made of transparent components that allow infrared light to pass through. At a position lower than the flow path R of the liquid raw material LM flowing in the gasification space K, a liquid accumulation section E is provided in the gasification section 22 for the liquid raw material LM to flow into.

2. The vaporizer according to claim 1, characterized in that, The vaporization section 22 is made of bent tubing.

3. The vaporizer according to claim 1, characterized in that, It includes a reflective component 28, which is arranged outside the heater H in a manner surrounding the vaporization section 22, and whose inner surface opposite the vaporization section 22 is formed as a mirror 28k that reflects infrared light.

4. The vaporizer according to claim 1 or 3, characterized in that, An auxiliary reflector 89 is disposed on the side of the heater H opposite to the vaporizer body 20. The surface of the auxiliary reflector 89 that reflects infrared light toward the vaporizer body 20 is a mirror surface 89k.

5. The vaporizer according to claim 1 or 3, characterized in that, A temperature detector 70 for measuring infrared radiation is configured with a gap d2, d3 of width M2, M3 between the vaporization section 22 and the heater H relative to the vaporizer body 20 and the heater H.

6. The vaporizer according to claim 5, characterized in that, The temperature detector 70 consists of a graphite infrared absorber 78 that absorbs infrared rays and is heated, and a temperature detection element 71 embedded in the infrared absorber 78 and detecting the temperature of the infrared absorber 78.

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