JP7631202B2 - Liquid Material Vaporizer - Google Patents

Description

The present invention relates to a liquid material vaporization device for vaporizing a liquid material.

In the semiconductor manufacturing process, a material gas obtained by vaporizing a liquid material that is liquid at room temperature may be used as a process gas for adsorption onto the substrate surface. For example, when forming an atomic-level thin film on a substrate by the ALD (Atomic Layer Deposition) method, the liquid material may be an organometallic liquid material containing elements such as Sr (strontium), Ba (barium), and La (lanthanum), which have low vapor pressure and high viscosity, dissolved in a solvent such as ECH (ethylcyclohexane) or THF (tetrahydrofuran). In recent years, liquid materials that use a material that is solid at room temperature as a solute and are dissolved in a solvent have also begun to be used. In the following, the term "liquid material" is used regardless of the state of the solute at room temperature, and materials that do not contain a solute may also be referred to as "liquid material."

There are two types of devices for vaporizing liquid materials: the baking method, in which the liquid material is vaporized by bubbling or other methods inside a tank in which it is stored, and the instantaneous vaporization method, in which the liquid material is sprayed into a vaporization chamber kept at a high temperature by a heater or other device, causing it to vaporize instantly.

With the baking method, when a liquid material in which a solid material as mentioned above is dissolved in a solvent is vaporized, the solute with a low vapor pressure remains in the tank, which poses the problem that the liquid material tends to become concentrated.

On the other hand, liquid material vaporization devices using the instantaneous vaporization method include an internal mixing method (see Patent Document 1), in which the liquid material and carrier gas are mixed in advance and then sprayed into the vaporization chamber, and an external mixing method (see Patent Document 2), in which the liquid material and carrier gas are mixed when supplied to the vaporization chamber.

In the instantaneous vaporization method, the area near the liquid material nozzle that opens into the vaporization chamber becomes very hot, so only the solvent in the liquid material evaporates near the nozzle, and the solute may remain. This can cause the liquid material supply path to become blocked or the nozzle to become clogged.

To solve these problems, Patent Document 3 proposes a liquid material vaporizer that combines an internal mixing method and an external mixing method. This liquid material vaporizer is equipped with a material supply system having a material injection nozzle that sprays a gas-liquid mixture of a liquid material and a carrier gas into the vaporization chamber, a carrier gas supply system having a carrier gas flow path formed to pass through the outer surface of the material injection nozzle, and a ring-shaped carrier gas outlet that injects carrier gas into the vaporization chamber from around the tip opening of the material injection nozzle. In other words, it is thought that the material injection nozzle can be cooled by the carrier gas supplied around the material injection nozzle by the carrier gas supply system, or that the carrier gas can be used to prevent heat transfer from the vaporization chamber to the material injection nozzle, thereby preventing only the solvent of the liquid material from evaporating.

However, even with the above configuration, it may not be possible to sufficiently prevent only the solvent from evaporating, especially when vaporizing a liquid material in which a solid material is the solute. Even if the so-called solvent skip phenomenon could be prevented, the consumption of carrier gas used for cooling or insulation would be very large.

JP 2006-108230 A JP 2007-46084 A Patent No. 5004890

The present invention has been made in consideration of the problems described above, and aims to provide a liquid material vaporization device that can sufficiently cool the liquid material so that it does not vaporize upstream of the vaporization chamber, and that can also reduce the consumption of the medium used for cooling.

That is, the liquid material vaporization device of the present invention is characterized by comprising a material supply system having a vaporization chamber in which the liquid material is heated and a material gas is produced by vaporizing the liquid material, a material supply path through which a gas-liquid mixture of the liquid material and a carrier gas flows, and a material outlet through which the gas-liquid mixture that has passed through the material supply path is ejected into the vaporization chamber, a cooling system having a cooling flow path through which at least a solvent that dissolves components contained in the liquid material flowing through the material supply path flows and which is formed so that the material outlet side of the material supply path is cooled, and a solvent outlet through which a refrigerant that has passed through the cooling flow path is ejected into the vaporization chamber.

In this way, the solvent flows through the cooling flow path, and the cooling flow path is formed so as to cool the material outlet side of the material supply path, so that the solvent can be vaporized near the material outlet, which is the hottest, and can be sufficiently cooled by the latent heat of vaporization. This makes it possible to prevent the liquid material from vaporizing upstream of the vaporization chamber, and to prevent problems such as clogging and blockage of the flow path.

In addition, the solvent flowing through the cooling flow path can be evaporated near the material outlet and pinpoint cooled using the latent heat of vaporization, significantly reducing the amount of medium consumed for cooling compared to cooling or insulation using carrier gas alone.

Furthermore, the solvent evaporated in the cooling flow path is supplied to the vaporization chamber, which reduces the partial pressure of the liquid material in the vaporization chamber and further aids in vaporization. In addition, the components contained in the liquid material dissolve in the solvent ejected from the solvent ejection port, so even if some components of the liquid material remain near the material ejection port, it is expected that such components will be dissolved and removed in the vaporized solvent.

To prevent the solvent sprayed from the cooling system into the vaporization chamber from affecting the destination of the material gas supply, while making it easier to remove the solute of the liquid material remaining in the material spray outlet, the liquid material should be a solid material dissolved in a solvent, and the refrigerant should be the solvent.

In order to make it easier for the solvent flowing through the cooling flow passage to evaporate near the material outlet, thereby enhancing the cooling effect due to the latent heat of vaporization, and also to improve the vaporization assisting effect of the solvent ejected from the solvent outlet on the liquid material in the vaporization chamber, it is sufficient that a gas-liquid mixture of solvent and carrier gas flows through the cooling flow passage, and that the gas-liquid mixture ejected from the material outlet and the solvent ejected from the solvent outlet are mixed within the vaporization chamber.

In order to allow the liquid material to begin evaporating after being sprayed into the vaporization chamber, while allowing the solvent flowing through the cooling flow path to begin vaporizing within the cooling flow path and locally cool the area near the material outlet by the latent heat of vaporization, the material supply path may include a first nozzle section whose flow path area decreases near the material outlet, and the cooling flow path may include a second nozzle section that is located a predetermined distance upstream from the solvent outlet and whose flow path area decreases and then increases.

A preferred configuration example of the second nozzle is one in which the first nozzle section is cooled by the latent heat of vaporization of the solvent evaporating at the outlet of the second nozzle section.

In order to increase the time that the evaporated refrigerant in the cooling flow passage remains in the vicinity of the material outlet and further enhance the cooling effect, a retention chamber in which the evaporated solvent remains may be formed on the outlet side of the second nozzle section.

In order to ensure that the liquid material ejected from the material outlet and the solvent ejected from the solvent outlet are thoroughly mixed in the vaporization chamber and to facilitate further vaporization of the liquid material, the multiple solvent outlets are arranged in a circle around the material outlet, and the ejection direction of each of the multiple solvent outlets is configured to form a spiral with the ejection direction of the material outlet as the central axis.

In order to ensure that the liquid material is sufficiently mixed with the carrier gas in the vaporization chamber and sprayed to the periphery of the vaporization chamber, and to promote the vaporization of the liquid material, a liquid material vaporization device may be provided that includes a material supply system having a vaporization chamber in which the liquid material is heated to produce a material gas from the vaporized liquid material, a material supply path through which a gas-liquid mixture of the liquid material and the carrier gas flows, and a material outlet through which the gas-liquid mixture that has passed through the material supply path is ejected into the vaporization chamber, and a cooling system having a cooling flow path through which the carrier gas flows and which is formed so that the material outlet side of the material supply path is cooled by the carrier gas, and a solvent outlet through which the carrier gas that has passed through the cooling flow path is ejected into the vaporization chamber, and one or more of the material outlets are formed to surround the periphery of the solvent outlet.

In this way, with the liquid material vaporization device according to the present invention, the refrigerant in a liquid state flows in the material supply path through which the liquid material flows so as to cool the material outlet side, so that the area near the material outlet can be pinpoint-cooled by the latent heat of vaporization of the refrigerant. This prevents the liquid material from evaporating in front of the vaporization chamber, and also reduces the consumption of the refrigerant through localized cooling.

1 is a schematic diagram of a liquid material vaporizing device according to a first embodiment of the present invention; FIG. 2 is a schematic cross-sectional view showing the structure of the sprayer according to the first embodiment. FIG. 2 is a schematic cross-sectional perspective view showing the structure of the sprayer according to the first embodiment. FIG. 2 is a schematic partial perspective view showing an enlarged view of the vicinity of the spray nozzle of the sprayer according to the first embodiment. FIG. 11 is a schematic cross-sectional view showing the structure of a sprayer according to a second embodiment. FIG. 11 is a schematic cross-sectional perspective view showing the structure of a sprayer according to a second embodiment. FIG. 11 is a schematic cross-sectional view showing the structure of a sprayer according to a third embodiment.

REFERENCE SIGNS LIST 100...Liquid material vaporization device 1...First gas-liquid mixing mechanism 2...Second gas-liquid mixing mechanism 3...Vaporization mechanism 4...Sprayer 5...Vaporizer 51...Heater 52...Vaporization chamber 6...Material supply mechanism 61...Material introduction port 62...Material ejection port 63...Material supply path 64...First nozzle section 7...Coolant supply mechanism 71...Coolant introduction port 72...Solvent ejection port 73...Cooling path 74...Second nozzle section 75...Retention chamber

A liquid material vaporization apparatus 100 according to a first embodiment of the present invention will be described with reference to Figures 1 to 4. This liquid material vaporization apparatus 100 is used to vaporize liquid material and generate material gas. The generated material gas is used, for example, as a process gas supplied for various processes on the surface of a substrate.

The liquid material to be vaporized is a solute solid material dissolved in a solvent (liquefied raw material), and the vapor pressure of the solid material is lower than that of the solvent. For this reason, depending on the temperature and pressure, only the solvent may evaporate first, and only the solute solid material may remain without vaporizing.

Specifically, as shown in FIG. 1, this liquid material vaporization device 100 includes a first gas-liquid mixing mechanism 1 that mixes the liquid material with a carrier gas to generate a gas-liquid mixture, a second gas-liquid mixing mechanism 2 that mixes a solvent that constitutes part of the liquid material with the carrier gas to generate a gas-liquid mixture, and a vaporization mechanism 3 in which the liquid material is heated to generate a material gas.

The first gas-liquid mixing mechanism 1 is equipped with a first valve unit 11 that controls the flow rate of the liquid material supplied to the carrier gas.

The second gas-liquid mixing mechanism 2 has the same configuration as the first gas-liquid mixing mechanism 1, and includes a second valve unit 21 that controls the flow rate of the solvent supplied to the carrier gas. In this embodiment, the carrier gas supplied to the first gas-liquid mixing mechanism 1 and the carrier gas supplied to the second gas-liquid mixing mechanism 2 are the same type of gas, and for example, N ₂ (nitrogen) is used. The solvent supplied to the second gas-liquid mixing mechanism is used as a refrigerant to prevent the liquid material from evaporating in the sprayer 4 described later. In addition, this solvent is the same type as the solvent constituting the liquid material supplied to the first gas-liquid mixing mechanism 1. Note that the solvent supplied to the second gas-liquid mixing mechanism 2 may be different from the solvent constituting the liquid material supplied to the first gas-liquid mixing mechanism 1 as long as it can dissolve the solid material that is the solute of the liquid material.

The vaporization mechanism 3 is composed of a sprayer 4 arranged on the upstream side and a heater 5 arranged on the downstream side. The sprayer 4 sprays the gas-liquid mixture supplied from each gas-liquid mixing mechanism into the heater 5. The heater 5 has a vaporization chamber 52 formed therein and a heater 51 configured to keep the inside of the vaporization chamber 52 at a constant temperature.

The details of the sprayer 4 are described below with reference to Figures 2 to 4.

The sprayer 4 is configured so that each gas-liquid mixture is supplied from the base end side, and the liquid material etc. is sprayed into the vaporization chamber 52 from the tip surface facing the vaporization chamber 52. This sprayer 4 is roughly cylindrical in shape, and has a flow path through which the gas-liquid mixture flows and a nozzle portion for adjusting the pressure inside. That is, the sprayer 4 is equipped with a material supply system 6 that supplies the liquid material into the vaporization chamber 52, and a cooling system 7 that supplies a refrigerant to prevent the liquid material flowing in the material supply system 6 from evaporating. The gas-liquid mixture flows synchronously through the material supply system 6 and the cooling system 7, respectively.

2 and 3, the material supply system 6 is composed of one material introduction port 61 that opens on the end face on the base end side of the sprayer 4 and through which a gas-liquid mixture consisting of liquid material and carrier gas is supplied from the first gas-liquid mixing mechanism 1, a material outlet 62 that is on the end face on the tip side of the sprayer 4 and from which the gas-liquid mixture containing the liquid material is ejected into the vaporization chamber 52, and a material supply path 63 that is a flow path connecting the material introduction port 61 and the material outlet 62 and through which the gas-liquid mixture flows. This material supply system 6 is formed along the central axis of the roughly cylindrical sprayer 4.

In the material supply path 63, a first nozzle section 64 is formed near the material outlet 62, where the flow path area is reduced. The outlet of the first nozzle section 64 is aligned with the material outlet 62. Therefore, the gas-liquid mixture passing through the first nozzle section 64 is squeezed once and then expands in the vaporization chamber 52.

In this embodiment, five cooling systems 7 are formed to surround the material supply system 6, and the material supply system 6 and the cooling system 7 are configured to be closest to each other at the tip side of the sprayer 4 facing the vaporization chamber 52. Specifically, as shown in Figures 2 and 3, the cooling system 7 includes a refrigerant inlet port 71 to which a gas-liquid mixture consisting of a solvent and a carrier gas is supplied from the second gas-liquid mixing mechanism 2, a solvent outlet 72 from which the liquid or gas introduced from the refrigerant inlet port 71 is sprayed into the vaporization chamber 52, and a cooling flow path 73 that connects the refrigerant inlet port 71 and the solvent outlet 72 and through which the gas-liquid mixture used as a refrigerant flows.

The cooling flow passage 73 is formed so that the material outlet 62 side of the material supply passage 63 is cooled by the refrigerant. Specifically, the cooling flow passage 73 is provided parallel to the material supply passage 63 at the base end side of the sprayer 4, but is bent obliquely with respect to the axial direction of the sprayer 4 at the tip end side of the sprayer 4 so as to approach the material outlet 62 side. The cooling flow passage 73 also includes a second nozzle portion 74 provided at a position a predetermined distance upstream from the solvent outlet 72. The second nozzle portion 74 is configured so that the flow passage area is reduced and then expanded, and is arranged so that the position of the second nozzle portion 74 with respect to the axial direction of the sprayer 4 is approximately the same as that of the first nozzle portion 64.

Because of this configuration, the solvent contained in the gas-liquid mixture is in a liquid state at the base end of the cooling flow path 73, but evaporates when it passes through the second nozzle portion 74 at the tip end of the refrigerant supply path. Therefore, the vicinity of the first nozzle portion 64 and the material outlet 62 is pinpoint-cooled by the latent heat of vaporization of the solvent flowing through the cooling flow path 73.

Next, the relative positions of the material nozzle 62 and the solvent nozzle 72 will be explained with reference to Figure 4. As shown in Figure 4, the central portion of the tip face of the sprayer 4 is recessed in a cone shape, with the material nozzle 62 opening at the innermost portion. The five solvent nozzles 72 are arranged side by side on a circle centered on the material nozzle 62. The five solvent nozzles 72 open onto the sloping surface of the cone, and are formed so that each of the refrigerant nozzles forms a spiral with the nozzle direction of the material nozzle 62 as the central axis.

With the liquid material vaporization device 100 configured in this manner, the liquid solvent flowing through the cooling passage 73 can be vaporized at the tip side of the sprayer 4 facing the vaporization chamber 52 heated by the heater 51, particularly near the material outlet 62, and the latent heat of vaporization can be used to locally cool the tip side.

Therefore, in the liquid material flowing through the material supply path 63 near the material outlet 62, only the solvent evaporates, preventing the solute solid material from remaining.

Even if a small amount of the solvent constituting the liquid material vaporizes and solid material remains near the material outlet 62, the vaporized solvent is supplied from the solvent outlet 72 to the vicinity of the material outlet 62, so the remaining solid material can be dissolved again. Therefore, while supplying the material gas, the remaining material near the material outlet 62 can be removed in parallel. In addition, the partial pressure of the solid material in the vaporization chamber 52 can be reduced by the gasified solvent supplied from the solvent outlet 72 to the vaporization chamber 52. This can promote the vaporization of the solid material in the vaporization chamber 52.

Furthermore, because pinpoint cooling is achieved using the latent heat of vaporization, the amount of refrigerant required for cooling can be significantly reduced compared to, for example, flowing only carrier gas through the cooling flow path 73 to cool the vicinity of the material outlet 62. In addition, because the solvent and carrier gas flow through the cooling flow path 73 in a gas-liquid mixture state, the solvent can be more easily vaporized at the tip side of the cooling flow path 73, improving cooling efficiency. Furthermore, the required supply pressure can be reduced compared to flowing only the solvent through the cooling flow path 73.

In addition, the liquid material vaporization device 100 of the first embodiment can achieve spraying of the liquid material into the vaporization chamber 52 by the internal mixing method using the material supply system 6, while also achieving spraying by the external mixing method by supplying vaporized solvent or carrier gas using each cooling system 7. By achieving a hybrid type of spraying that combines the internal mixing method and the external mixing method in this way, a spray state suitable for vaporizing the solid material contained in the liquid material can be achieved.

Next, a liquid material vaporization device 100 according to a second embodiment of the present invention will be described with reference to Figures 5 and 6. Note that the same reference numerals will be used to designate components corresponding to those described in the first embodiment.

As shown in Figures 5 and 6, the second embodiment of the liquid material vaporization device 100 differs from the first embodiment in the configuration of the cooling flow path 73. Specifically, the position of the second nozzle portion 74 in the cooling flow path 73 is arranged further upstream, and a retention chamber 75 in which the vaporized refrigerant temporarily resides is formed at the outlet of the second nozzle portion 74. The retention chamber 75 is a roughly rectangular parallelepiped space, and is formed so as to have the largest flow path area in the cooling flow path 73. In addition, the areas of the outlet port and inlet port are small compared to the inlet and outlet wall surfaces of the retention chamber 75.

In this way, the solvent that has passed through the second nozzle portion 74 and evaporated can be retained in the vicinity of the material outlet 62 for a predetermined period of time, thereby further enhancing the cooling effect.

Next, the third embodiment will be explained with reference to Figure 7.

In the third embodiment, the positional relationship between the material supply path 63 and the cooling flow path 73 is reversed compared to the previously described embodiments. That is, the flow path extending along the central axis of the sprayer 4 serves as the cooling flow path 73, and the multiple flow paths provided around it serve as the material supply paths 63. Furthermore, the material outlet 62 is formed so as to surround the solvent outlet 72 formed in the center of the tip face of the sprayer 4.

In the third embodiment, no liquid flows in the cooling flow path 73, and only the carrier gas flows as a coolant. On the other hand, a gas-liquid mixture of a liquid material in which a solid material is dissolved in a solvent and a carrier gas flows in the material supply path 63.

The liquid material vaporization device 100 configured in this manner can achieve hybrid mixing that combines internal mixing and external mixing, while allowing the liquid material to be sprayed to the periphery of the vaporization chamber 52 in a state where it is sufficiently mixed with the carrier gas within the vaporization chamber 52. This can promote the vaporization of the liquid material.

Other embodiments are described below.

The cooling flow path is not limited to one through which a gas-liquid mixture flows, and may be one through which only a liquid refrigerant flows, for example. The refrigerant is not limited to the solvent that constitutes the liquid material flowing through the material supply path, and may be another type of liquid. In this case, it is sufficient if it has the property of being able to dissolve the solute that constitutes the liquid material. Also, in the third embodiment, not only a carrier gas but also a liquid such as a solvent that acts as a refrigerant may be flowed through the cooling flow path.

The solute of the liquid material is not limited to a solid material, and the liquid material may be one in which the solute is, for example, an organic metal liquid material dissolved in a solvent.

In the first and second embodiments, multiple cooling systems are provided for a material supply system, but only one cooling system may be provided for one material supply system. Even if multiple cooling systems exist, the solvent outlets may eventually merge. In this case, the solvent outlet may be formed in a ring shape to surround the material outlet.

The ejection directions of the material ejection nozzle and the solvent ejection nozzle are not limited to those shown in each embodiment. For example, the ejection direction of the material ejection nozzle and the ejection direction of the solvent ejection nozzle may be parallel to each other.

The carrier gas and the carrier gas are not limited to being the same type of gas, but may be different types of gas.

In addition, parts of each embodiment may be combined or modified as long as this does not go against the spirit of the present invention.

Thus, according to the present invention, a liquid material vaporization device can be provided that can prevent the liquid material from evaporating in front of the vaporization chamber and also reduce the amount of refrigerant consumed.

Claims (8)

a vaporization chamber in which a liquid material is heated and a material gas is generated by vaporizing the liquid material;
a material supply system including a material supply passage through which a gas-liquid mixture obtained by mixing a liquid material and a carrier gas flows, and a material ejection port through which the gas-liquid mixture that has passed through the material supply passage is ejected into the vaporization chamber;
a cooling system including a cooling flow path through which a fluid different from the gas-liquid mixture flows, the cooling flow path being formed so that at least a solvent, which is a liquid in which components contained in the liquid material flowing through the material supply path dissolves, flows, and the material supply path is cooled on the material outlet side; and a solvent outlet through which the solvent, which is a liquid that has passed through the cooling flow path, is ejected into the evaporation chamber. the liquid material flowing through the material supply path is a solid material dissolved in a solvent,
2. The liquid material vaporizer according to claim 1, wherein the solvent flowing through the cooling flow passage is the same type as the solvent constituting the liquid material. A gas-liquid mixture of a solvent and a carrier gas flows through the cooling flow path,
3. The liquid material vaporizing apparatus according to claim 1, wherein the gas-liquid mixture ejected from the material ejection port and the solvent ejected from the solvent ejection port are mixed in the vaporizing chamber. The material supply path includes a first nozzle portion having a flow path area reduced in the vicinity of the material ejection port,
4. A liquid material vaporization device according to claim 1, wherein the cooling flow passage is provided at a predetermined distance upstream from the solvent outlet and includes a second nozzle portion whose flow passage area decreases and then increases. The liquid material vaporizer according to claim 4, wherein the first nozzle section is cooled by the latent heat of vaporization of the solvent evaporating at the outlet of the second nozzle section. The liquid material vaporizer according to claim 4 or 5, wherein a retention chamber in which evaporated solvent is retained is formed on the outlet side of the second nozzle portion. The solvent outlets are arranged in a circle around the material outlet,
7. The liquid material vaporizing device according to claim 1, wherein each of the solvent outlets has an outlet direction that forms a spiral shape with the outlet direction of the material outlet as a central axis. a vaporization chamber in which a liquid material is heated and a material gas is generated by vaporizing the liquid material;
a material supply system including a material supply passage through which a gas-liquid mixture, which is a mixture of a liquid material and a carrier gas, flows, and a material ejection port through which the gas-liquid mixture that has passed through the material supply passage is ejected into the vaporization chamber;
a cooling system including a cooling flow path through which a fluid different from the gas-liquid mixture flows, a carrier gas and a liquid solvent flow, and a cooling system formed so as to cool the material outlet side of the material supply path, and a solvent outlet through which the carrier gas and the liquid solvent that have passed through the cooling flow path are ejected into the vaporization chamber,
A liquid material vaporizing device in which one or more of the material jets are formed so as to surround the periphery of the solvent jet.

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