vaporizer

Abstract

Provided is a vaporizer enabling efficient, stable vaporization of a liquid raw material for semiconductor manufacturing, at the lowest temperature possible and without uneven heating. A vaporizer 10 is constituted of: a liquid raw material supply unit 12 for supplying a liquid raw material LM for semiconductor manufacturing; a vaporization unit 20 having in the interior a vaporization space K in which to vaporize the supplied liquid raw material LM; and a raw material gas discharge unit 40 for feeding vaporized raw material gas VG out to the next step. The vaporization unit 20 comprises: a vaporizer body 22 that is constituted of a transparent member through which infrared rays are transmitted, the infrared rays passing through the vaporization space K to be transmitted from a first side wall 22h to an opposing second wall 22h; transparent spherical bodies 30 which are packed in the vaporization space K and through which infrared rays are transmitted; a heater H that is arranged with a gap d of a width M provided from the vaporizer body 22, and irradiates the vaporizer body 22 with infrared rays; and a reflection member 28 in which a surface facing the vaporizer body 22, with the heater H placed therebetween, is a mirror surface 28k at which infrared rays are reflected.

Description

vaporizer

[0001] The present invention relates to a vaporizer capable of stably vaporizing a liquid raw material used in the semiconductor manufacturing process with high efficiency and without uneven heating.

[0002] Semiconductor manufacturing processes include processes that require liquid raw materials for their processing, such as an oxide film formation process or a thin film formation process. For example, in the oxide film formation process, 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 form an oxide film on the surface of a silicon wafer, and the oxide film formation process is carried out. In the thin film formation process, a liquid raw material is vaporized to form a raw material gas, which is then supplied into a thin film formation apparatus to form a thin film on a substrate.

[0003] A vaporizer is used to vaporize and supply the liquid compound in each of the above processes. A conventional vaporizer, for example, has a vaporization surface with many holes in the vaporizer body. While the vaporization surface is heated by a heater, the liquid raw material is ejected from a nozzle to form a mist of fine droplets, which are then carried by a carrier gas flow and sprayed onto the vaporization surface, thereby vaporizing the compound. In such a vaporizer, the fine droplets come into contact with a breathable member, thereby improving vaporization efficiency. (See Patent Documents 1 and 2.)

[0004] However, conventionally, breathable members used to vaporize fine droplets of liquid source material were heated by heat conduction from a heater, and because there were areas far from the heater where the heat did not reach sufficiently and the temperature was low, it was not possible to supply heat uniformly throughout the breathable member. Therefore, there was a risk of clogging in the low-temperature areas of the breathable member due to the droplets not being vaporized. If the liquid source material is not vaporized 100%, the unvaporized liquid becomes particles and adheres to the wafer surface, causing serious damage to thin film formation. Therefore, the vaporizer described in Patent Document 3 was proposed.

[0005] In the vaporizer described in Patent Document 3, the breathable member that vaporizes the droplets of the liquid raw material is made of an opaque material such as ceramic that easily absorbs infrared rays, and the vaporizer is designed to ensure that the temperature of the entire breathable member is uniform when the droplets of the liquid raw material are vaporized using this opaque breathable member. That is, infrared rays from a heater are irradiated onto the entire outer surface of the breathable member placed in the vaporization section via a transparent quartz sleeve tube.

[0006] Japanese Patent Application Laid-Open No. 2005-347598 Japanese Patent Application Laid-Open No. 10-85581 Japanese Patent Application Laid-Open No. 2009-188266

[0007] This method allows the entire outer surface of the breathable member to be uniformly heated by radiant heat from the heater, ensuring that all droplets flowing along the outer surface of the breathable member are vaporized evenly. However, because infrared rays cannot pass through the opaque breathable member, the inside of the breathable member is heated by heat transfer from the surface. Meanwhile, droplets flowing along the surface of the breathable member flow from the surface of the breathable member to the inner side through the micropores inside the member, along with the airflow accompanying the exhaust of vaporized gas. If the breathable member is thick, the temperature on the inner side will be lower than on the outer side, where infrared rays are directly irradiated, and this is likely to cause temperature variations and lead to clogging on the inner side of the breathable member. As a result, limitations on the thickness of the breathable member arise, hindering vaporization efficiency.

[0008] In addition to temperature unevenness, another important aspect of the liquid precursor vaporization process is to avoid excessively high temperatures during vaporization of the liquid compound precursor. The reason for this is that the liquid compounds used in semiconductor film formation are sensitive to temperature and tend to polymerize at high temperatures. As the temperature rises, dimers are formed, followed by trimers and then polymers, increasing the molecular weight. In other words, they become polymeric compounds. This increases the boiling point, making vaporization difficult and ultimately solidifying, making film formation impossible. At even higher temperatures, the compound begins to decompose, making it impossible to form a thin film. Therefore, vaporizers must vaporize at the lowest possible temperature. To achieve this, vaporizers must vaporize at the lowest possible temperature and with an extremely uniform temperature distribution.

[0009] The present invention has been made in consideration of the above-mentioned conventional problems, and aims to provide a vaporizer that can vaporize liquid raw materials for semiconductor manufacturing at the lowest possible temperature, without uneven heating, and with high efficiency and stability.

[0010] In order to achieve the above object, the present invention (claim 1) provides a vaporizer 10 configured as follows: The vaporizer 10 includes a liquid source supply unit 12 that supplies a liquid source LM for semiconductor manufacturing, a vaporization unit 20 having an internal vaporization space K for vaporizing the supplied liquid source LM, and a source gas discharge unit 40 that sends the vaporized source gas VG to a subsequent process, wherein the vaporization unit 20 includes: a vaporizer body 22 made of a transparent material that transmits infrared rays through the vaporization space K from one side wall 22h to the opposing side wall 22h, transparent spherical bodies 30 that transmit infrared rays and are filled in the vaporization space K, a heater H that is disposed at a gap d of width M from the vaporizer body 22 and irradiates infrared rays to the vaporizer body 22, and a reflecting member 28 that has a surface facing the vaporizer body 22, with the heater H interposed therebetween, the surface of which is a mirror surface 28k that reflects infrared rays.

[0011] Claim 2 further provides an auxiliary reflecting member 29 on the heater H (Figures 2 and 3), and is characterized in that in the vaporizer 10 described in claim 1, an auxiliary reflecting member 29, the surface facing the vaporizer main body 22 of which is a mirror surface 29k that reflects infrared rays, is provided on the surface of the heater H opposite the vaporizer main body 22.

[0012] Claim 3 is a modified example of the vaporizer body 22 (Figure 7), which is characterized in that in the vaporizer 10 described in claim 1, the vaporizer body 22 is made of a pipe material formed in a spiral shape.

[0013] Claim 4 relates to ventilation of the gap d (FIG. 2), and is characterized in that in the vaporizer 10 described in claim 1, a replacement gas supply section 25 that communicates with the gap d and supplies a replacement gas, and a replacement gas discharge section 26 that discharges the supplied replacement gas are provided in the vaporizing section 20, and the gap d between the vaporizer main body 22 and the heater H serves as a flow path for the replacement gas.

[0014] Claim 5 relates to the size of the gap d (Figure 4), and is characterized in that in the vaporizer 10 described in claim 1, the width M of the gap d is formed larger than the thickness δ of the thermal boundary layer T formed around the heater H.

[0015] According to the present invention (claim 1), vaporizer body 22 and spherical bodies 30 are made of transparent materials that transmit infrared rays, so that the infrared rays emitted from heater H pass through them evenly and without unevenness throughout. Then, because the infrared rays are reflected countless times by reflecting member 28, they pass through vaporizer body 22 and spherical bodies 30 evenly throughout, and all of the liquid source LM flowing down between spherical bodies 30 is heated evenly and vaporized without unevenness.

[0016] Furthermore, since heater H is provided at a distance d of width M from vaporizer body 22, heat conduction from heater H to vaporizer body 22, which would cause uneven heating, is blocked. As a result, the entire liquid source LM supplied into vaporization space K is directly and uniformly heated only by radiant heat from infrared rays while flowing down between spheres 30 filled in vaporization space K.

[0017] If the vaporizer body 22 is formed in a spiral shape (claim 3), the flow path of the liquid raw material LM becomes longer and the liquid raw material LM flows down while swirling, so that the time of exposure to infrared rays becomes longer and more reliable vaporization can be achieved.

[0018] Furthermore, the gap d between the vaporizer body 22 and the heater H serves as a flow path, and when a replacement gas is passed through this gap d (claim 4), the heated gas (air) that has accumulated in this portion and that has been heated by the heater H is discharged. As a result, the liquid raw material LM supplied into the vaporization space K is not affected by the heated gas (air), and is directly heated more evenly only by the radiant heat of the infrared rays emitted from the heater H.

[0019] In addition, if the size (width M) of the gap d is made larger than the thickness δ of the thermal boundary layer T (claim 5), heat transfer from the replacement gas flowing through the gap d, which is the flow path, to the vaporizer body 22 is reliably blocked.

[0020] 1. A cross-sectional view of a vaporizer according to a first embodiment of the present invention. 2. A cross-sectional view along A-A' in FIG. 3. 3. A cross-sectional view along B-B' in FIG. 1. 4. A partially enlarged view of the gap in FIG. 2. 5. A cross-sectional view of a vaporizer according to a second embodiment. 6. A cross-sectional view along C-C' in FIG. 5. 7. (a) A diagram showing a cross section of a vaporizer according to a third embodiment, and (b) another example of a straight tube portion. 8. A conceptual diagram of a state in which a liquid raw material flowing between spherical bodies is heated by radiant heat.

[0021] The present invention will be described below with reference to the drawings. Vaporizer 10 vaporizes liquid source LM to produce source gas VG, which is then supplied to various semiconductor manufacturing equipment that uses the source gas VG. Vaporizer 10 is roughly composed of a liquid source supply unit 12, a vaporization unit 20, and a source gas discharge unit 40. Liquid source supply unit 12 supplies liquid source LM to vaporization unit 20, which vaporizes the supplied liquid source LM, and source gas discharge unit 40 discharges the vaporized source gas VG to the next process. Liquid source supply unit 12 can supply liquid source LM as droplets or as atomized material, and this can be selected appropriately according to the specifications required for vaporizer 10.

[0022] There are various liquid sources LM, and they are selected appropriately depending on the source gas VG used in various semiconductor manufacturing equipment. Here, hydrogen peroxide water is used as a representative example.

[0023] (First embodiment: Figures 1 to 3) As described above, the liquid raw material supply section 12 of the vaporizer 10 of the present invention can supply the liquid raw material LM as droplets or as an atomized material. Below, we will explain the case where the liquid raw material LM is atomized, and then provide a supplementary explanation of the case where it is supplied as droplets.

[0024] The liquid source supply unit 12 is equipped with a liquid source inlet pipe 12a and a carrier gas inlet pipe 12b. The liquid source inlet pipe 12a protrudes from the center of the top surface of the liquid source supply unit 12, and has a liquid source supply hole 12c drilled in its center, through which the liquid source LM passes. The tip of the liquid source supply hole 12c is narrowed into a cone shape, and is provided with a spray nozzle 12d that opens to the bottom surface of the liquid source supply unit 12. A carrier gas inlet pipe 12b is provided on the side of the liquid source inlet pipe 12a, and a carrier gas supply path 12e that connects to the spray nozzle 12d and creates a Venturi effect is provided around the outer periphery of the liquid source inlet pipe 12a.

[0025] The vaporizing section 20 is generally composed of a vaporizer body 22, a spherical body 30, a heater H, and a reflecting member 28.

[0026] Vaporizer body 22 is a cylindrical hollow vessel that is open at its top (upper side in FIG. 1 ) and closed at its bottom. The closed bottom is referred to as bottom member 22s. The open end at the top is blocked by the main body of liquid source supply unit 12. The main body portion blocking the open end at the top of vaporizer body 22 is referred to as ceiling member 22t. The space between ceiling member 22t and bottom member 22s of vaporizer body 22 is vaporization space K where liquid source LM is vaporized. The cylindrical portion of the hollow vessel is sidewall 22h. A transparent material that can transmit infrared rays radiated from heater H is selected as the material for vaporizer body 22 and liquid source supply unit 12, and transparent quartz glass is used in this embodiment.

[0027] The interior (vaporization space K) of vaporizer main body 22 is filled with spherical bodies 30. In Fig. 1, spherical bodies 30 are filled with a space above them so that an atomization space S is formed above them in order to atomize the liquid source LM. Similar to vaporizer main body 22, spherical bodies 30 are made of a transparent material that can transmit infrared rays emitted from heater H. In this embodiment, spheres made of transparent quartz glass and having a diameter of, for example, 2 to 5 mm are used.

[0028] If necessary, a porous filter 23 is placed on top of the packed spheres 30. Any material may be used for the porous filter 23 as long as it is not affected by the liquid source LM and allows it to pass through smoothly, but in this case, a porous semi-molten quartz glass porous body is used, in which contact portions of quartz glass powder particles are fused and joined in a semi-molten state so that the porous filter 23 is permeable to infrared rays emitted from the heater H and can be welded to the vaporizer body 22.

[0029] The reason why transparent quartz glass is used as the material for vaporizer body 22 and spherical body 30 is that it is capable of transmitting infrared rays emitted from heater H, and the infrared rays can penetrate to the center of vaporizer body 22.

[0030] Although the spherical body 30 is spherical in this embodiment, it is not limited to a sphere and may be made of, for example, granular quartz. This has a larger surface area, which is preferable in terms of increasing the vaporization efficiency of the liquid source.) However, any material that may chip due to vibration or other external forces and generate particles should not be used.

[0031] A tubular source gas discharge section 40 is provided in a hole drilled in the lower end side surface of the hollow vessel constituting the vaporizer main body 22, and a porous filter 24 is attached to the end of this source gas discharge section 40 on the vaporizer main body side. Porous filter 24 may be any filter that is not affected by source gas VG and allows source gas VG to pass through smoothly. The porous filter 24 is the same as the porous filter 23 described above.

[0032] A cylindrical heater block 60 incorporating a heater GH for heating the raw material gas is attached to the outer periphery of the tubular raw material gas discharge part 40 .

[0033] A plurality of heaters H (two in this embodiment) are provided upright on both sides of the vaporizer body 22. A gap d is provided between each heater H and the side wall 22h of the vaporizer body 22. This blocks heat transfer from the heater H to the vaporizer body 22. However, since gas (air) is present in this gap d, heat from the heater H is transferred to the vaporizer body 22. Therefore, as will be described later, it is possible to use the gap d as a flow path for gas replacement.

[0034] Reflecting member 28 is a cylindrical member provided to reflect infrared rays emitted from heater H toward vaporization space K, and its inner surface is finished to mirror surface 28k by plating, polishing, or the like, or is covered with aluminum foil to form mirror surface 28k. Reflecting member 28 is provided so as to surround vaporizer body 22 outside heater H, as shown in Figure 3. Ceiling plate 21 is attached to the upper end of reflecting member 28, and bottom plate 27 is attached to the lower end thereof.

[0035] A hollow ring-shaped space is formed inside by the reflecting member 28, the side wall 22h of the vaporizer body 22, the ceiling plate 21 and the bottom plate 27, and a heater H is housed inside.

[0036] 3 uses auxiliary reflecting member 29. This auxiliary reflecting member 29 is not necessarily required because there is a main reflecting member 28 surrounding vaporizer body 22. This auxiliary reflecting member 29 is provided on the rear side of heater H, i.e., on the surface opposite sidewall 22h of vaporizer body 22, covering the entire rear surface of heater H, and the surface facing vaporizer body 22 is mirror surface 29k.

[0037] Next, a method for vaporizing the liquid source LM using the vaporizer 10 will be described. The heater H is energized to place the interior of the vaporization space K in a state in which the liquid source LM can be vaporized. Once the vaporization state is reached, the liquid source LM is supplied to the liquid source inlet pipe 12a of the liquid source supply unit 12, and the carrier gas CG is supplied to the carrier gas inlet pipe 12b. This creates a Venturi effect, and the liquid source LM is atomized and uniformly dispersed within the atomization space S from the spray nozzle 12d.

[0038] The mist-like liquid source LM sprayed into the atomization space S falls evenly onto the porous filter 23 and flows down toward the spherical bodies 30. Adjacent spherical bodies 30 in the vaporizer body 22 support each other through point contact, forming gaps P between them that are roughly triangular in plan view and comprised of complex concave spherical surfaces (FIG. 8). The liquid source LM that flows down toward the spherical bodies 30 wets the surfaces of the spherical bodies 30 as it flows down, or a significant portion of the liquid source LM collects in the gaps P, forming liquid pools.

[0039] On the other hand, infrared rays emitted from the heat source of heater H are emitted in the radial direction. A significant portion of the infrared rays from the surface of heater H facing vaporizer body 22 proceeds toward vaporizer body 22. The infrared rays emitted from the rear side are reflected by auxiliary reflecting member 29 on the rear of heater H (if auxiliary reflecting member 29 is not present, they are reflected by cylindrical main reflecting member 28) and proceed toward vaporizer body 22.

[0040] Because vaporizer body 22 is made of transparent quartz glass that transmits infrared rays, infrared rays traveling toward vaporizer body 22 are refracted while passing through side wall 22h of vaporizer body 22. Because the interior of vaporizer body 22 is filled with spherical bodies 30, infrared rays that reach vaporization space K inside vaporizer body 22 are refracted while passing through these spherical bodies 30, reach side wall 22h on the opposite side, and are further refracted while passing through it. To avoid complexity in the drawing, infrared rays are shown as straight lines.

[0041] Most of the infrared rays that have passed through vaporizer body 22 are reflected by mirror surface 28k on the opposite side of cylindrical reflecting member 28, and pass through vaporizer body 22 again. The remaining infrared rays are reflected by auxiliary reflecting member 29. The infrared rays repeat this process instantaneously and infinitely within cylindrical reflecting member 28.

[0042] On the other hand, the state of the infrared rays within the vaporization space K of the vaporizer body 22 instantaneously repeats infinite reflections and instantaneously becomes uniform. As a result, the temperature of the liquid source LM that flows through the vaporization space K and absorbs the uniform infrared rays becomes uniform throughout the vaporization space K. In other words, there is almost no heating due to heat transfer from the vaporizer body 22 and the spherical bodies 30, and the liquid source LM is heated only by the uniform infrared rays.

[0043] The infrared rays used here are mid-infrared rays, and when their wavelengths are between 2.5 μm and 4 μm, they include the absorption peak wavelength (3 μm) of water, the liquid source LM. Therefore, a portion of the mid-infrared rays that reach the vaporizer body 22 is absorbed by the thin film of liquid source LM formed on the surface of the spheres 30, or by the liquid source LM accumulated in the gap P, causing it to vaporize. If the thin film of liquid source LM is too thin, the infrared rays will pass through as is. Because the spheres 30 are made of transparent quartz glass that transmits infrared rays, the infrared rays that are not absorbed by the liquid source LM pass through the spheres 30 and exit on the other side.

[0044] The infrared rays that are not absorbed by the liquid source material LM pass through the spherical bodies 30 packed inside the vaporizer body 22 one after another, and then pass through the side wall 22h on the opposite side of the vaporizer body 22 to exit to the outside. The infrared rays that have exited the vaporizer body 22 are reflected by the mirror surface 28k (or a part of it is the auxiliary reflecting member 29) on the opposite side of the reflecting member 28, and return to the vaporizer body 22. The source gas VG vaporized in the vaporization space K rapidly increases in volume and is discharged from the source gas discharge part 40 to the next process.

[0045] In the vaporizer 10 of the present invention, the liquid source LM inside the vaporization space K can be heated uniformly and without unevenness using only infrared rays, so the vaporizer body 22 can be made larger. Even if the vaporizer body 22 is made larger, there is no outflow of unvaporized liquid source LM particles, which can cause a deterioration in the quality of the film formed on the wafer. Furthermore, because uniform heating is achieved using only infrared rays as described above, the liquid source LM can be vaporized at the minimum necessary temperature when heated, and the heating temperature does not need to be increased more than necessary. In other words, the use of the vaporizer 10 of the present invention greatly improves stability and vaporization efficiency.

[0046] The above case is when the liquid source LM is supplied in a mist state. When the liquid source LM is supplied without using the carrier gas CG, the liquid source LM drips and is distributed throughout the center of the porous filter 23. It then flows downward, gradually diffusing as it flows down the layer of spheres 30. Even in this case, the state of infrared rays in the vaporization space K is uniform, so uniform vaporization is guaranteed, just as above.

[0047] 1 to 3 show an example in which heat transfer to the vaporizer body 22 in the space where the heater H is located is taken into consideration. As described above, when the heater H is heated, the temperature of the surrounding gas (air) rises. The side wall 22h of the vaporizer body 22 is heated via this heated gas (air). Therefore, the width M of the gap d is devised and the gap d is used as a flow path for the replacement gas. This can be applied to all examples.

[0048] Therefore, as shown in the figure, a hole is provided in the ceiling plate 21, which serves as the replacement gas supply section 25, and a hole is provided in the bottom plate 27, which serves as the replacement gas discharge section 26. These allow the replacement gas (air) to flow into the space in which the heater H is disposed. As a result, the surrounding gas (air) heated by the heater H rises and is discharged from the replacement gas discharge section 26, and outside air at room temperature flows in instead from the replacement gas supply section 25, so that the space in which the heater H is disposed is maintained at the temperature of the replacement gas (air). As a result, most of the thermal influence of the heater H on the vaporizer body 22 in the space in which the heater H is disposed is eliminated.

[0049] However, the distance M of the gap d poses a problem. The room-temperature outside air flowing in from the replacement gas supply unit 25 rises along the heater H and gradually increases in temperature. If the distance (width M) between the heater H and the sidewall 22h of the vaporizer body 22 is close and smaller than the thickness δ of the thermal boundary layer T, the replacement gas that flows along the heater H and is heated by the heater H comes into contact with the sidewall 22h of the vaporizer body 22. As a result, the temperature of the sidewall 22h is affected by the heater H. Therefore, as shown in FIG. 4 , if the distance (width M) between the heater H and the sidewall 22h of the vaporizer body 22 is larger than the thickness δ of the thermal boundary layer T, the replacement gas that has not yet increased in temperature flows along the sidewall 22h between the heated thermal boundary layer T and the sidewall 22h, blocking the thermal influence of the heated thermal boundary layer T. This reliably eliminates the influence of the heated thermal boundary layer T in the space where the heater H is located.

[0050] (Second embodiment: FIGS. 5 and 6) In this case, the vaporizer body 22 is a double-tube structure, with a heater H provided inside the inner tube 22b. The vaporizer body 22 is composed of a cylindrical outer tube 22a, an inner tube 22b with a hemispherical upper end provided therein, and a bottom member 22s that closes the bottoms of both tubes. The upper opening of the outer tube 22a is closed by a block portion (ceiling member 22t) of the liquid source supply unit 12. The upper end of the inner tube 22b is located directly below the liquid source introduction tube 12a. The space between the outer tube 22a and the inner tube 22b is a vaporization space K, which is filled with spherical bodies 30. The spherical bodies 30 are filled to a height that hides the upper end of the inner tube 22b. If necessary, a porous filter 23 is provided on top of the spherical bodies 30. The porous filter 23 is not depicted in the illustrated embodiment. The space between the spherical body 30 (porous filter 23) and the lower surface of the ceiling member 22t is the atomization space S.

[0051] A gap d is provided between the mirror surface 28k of the reflecting member 28 and the outer tube 22a to prevent thermal influence from the reflecting member 28. A gap d is also provided between the heater H and the inner tube 22b to prevent thermal influence from the reflecting member 28. A replacement gas supply unit 25 and a replacement gas discharge unit 26 are provided in the gap d between the heater H and the inner tube 22b, and are configured to allow replacement gas to flow through the gap d. Furthermore, as already mentioned, the gap d may be made larger than the width M of the thermal boundary layer T to prevent thermal influence from the heater H. The configuration other than the above is the same as that of the first embodiment.

[0052] A heater block 60 is provided on the bottom plate 27 covering the bottom of the reflecting member 28, and a source gas heater GH is attached to it. In the vaporizer 2 of the second embodiment, the liquid source LM is atomized in the same manner as in the first embodiment. Although not shown, the second embodiment differs from the first embodiment when the liquid source LM is supplied as droplets without using a carrier gas CG. Specifically, the dropped liquid source LM falls onto the spheres 30 directly above the hemispherical heads of the inner tube 22b, where it is distributed throughout this area, and then flows through the porous filter 23 or directly into the gaps P between the spheres 30. Because the hemispherical heads are located directly below this area, the liquid source LM that flows down spreads along the hemispherical heads and continues to flow down around the inner tube 22b. During this time, the liquid source LM is uniformly heated by radiant heat, vaporizes, and is discharged from the source gas discharge section 40.

[0053] (Third embodiment: FIG. 7) In this example, the vaporizer body 22 is formed from a spiral transparent quartz glass tube. Upper and lower porous filters 23 and 24 are installed in the upper and lower straight tube sections 22c and 22d, respectively, and spherical bodies 30 are filled between them. The reflecting member 28 is cylindrical, and the top and bottom ends are respectively attached to the ceiling plate 21 and the bottom plate 27. A transparent quartz glass tube serving as an enclosure for the heater H is inserted through the center of the ceiling plate 21 and the bottom plate 27, and the heat source for the heater H is installed vertically inside this tube. A gap d is provided between the transparent quartz glass tube of the heater H and the spiral vaporizer body 22. Although not shown, a replacement gas can be flowed through this portion, and the width M of the gap d can be set to be equal to or greater than the thickness δ of the thermal boundary layer T.

[0054] In this vaporizer 10, the liquid source LM supplied from the liquid source supply unit 12 flows through the upper porous filter 23 into the filled portion of the spheres 30 and is vaporized while rotating in a spiral. By making the vaporizer body 22 spiral, the vaporization path of the liquid source LM can be lengthened, but the height of the vaporizer 10 can be reduced, making the vaporizer 10 more compact. It is also possible to narrow the straight pipe sections 22c and 22d as shown in Figure 7(b) so that their inner diameters are equal to or smaller than the outer diameter of the spheres 30, and replace these sections with the upper or lower porous filters 23 and 24.

[0055] CG: carrier gas, d: gap, H: heater, GH: raw material gas heater, K: vaporization space, LM: liquid raw material, M: gap width, P: air gap, S: atomization space, T: thermal boundary layer, VG: raw material gas, δ: thickness of thermal boundary layer 10: vaporizer, 12: liquid raw material supply unit, 12a: liquid raw material inlet pipe, 12b: carrier gas inlet pipe, 12c: liquid raw material supply hole, 12e: carrier gas supply path, 12d: spray nozzle, 20: vaporizer unit, 21: ceiling plate, 22: vaporizer body, 22a: outer tube, 22b: inner tube, 22c: upper straight tube section, 22d: lower straight tube section, 22h: side wall, 22s: bottom member, 22t: ceiling member, 23, 24: porous filters, 25: replacement gas supply unit, 26: replacement gas discharge unit, 27: bottom plate, 28: reflecting member, 28k: mirror surface, 29: auxiliary reflecting member, 29k: mirror surface, 30: spherical body, 40: raw material gas discharge unit, 60: heater block

Claims

1. A vaporizer (10) comprising a liquid source supply unit (12) that supplies a liquid source material (LM) for semiconductor manufacturing, a vaporization unit (20) having an internal vaporization space (K) for vaporizing the supplied liquid source material (LM), and a source gas discharge unit (40) that sends the vaporized source gas (VG) to a subsequent process, wherein the vaporization unit (20) comprises: a vaporizer body (22) made of a transparent material that transmits infrared rays through the vaporization space (K) from one side wall (22h) to the opposing side wall (22h); transparent spherical bodies (30) that transmit infrared rays and are filled in the vaporization space (K); a heater (H) that is disposed at a gap (d) of width (M) from the vaporizer body (22) and irradiates infrared rays to the vaporizer body (22); and a reflecting member (28) that has a surface facing the vaporizer body (22) and that is a mirror surface (28k) that reflects infrared rays, with the heater (H) interposed therebetween.

2. A vaporizer as described in claim 1, characterized in that an auxiliary reflection member 29, the surface facing the vaporizer main body 22 of which is a mirror surface 29k that reflects infrared rays, is provided on the surface of the heater H opposite the vaporizer main body 22.

3. The vaporizer according to claim 1, wherein the vaporizer body 22 is made of a spirally formed pipe material.

4. A vaporizer as described in claim 1, characterized in that the vaporization section 20 is provided with a replacement gas supply section 25 that communicates with the gap d and supplies a replacement gas, and a replacement gas discharge section 26 that discharges the supplied replacement gas, and the gap d between the vaporizer main body 22 and the heater H serves as a flow path for the replacement gas.

5. A vaporizer according to claim 1, wherein the width M of the gap d is greater than the thickness δ of the thermal boundary layer T formed around the heater H.

Images