JPH1187327A - Liquid material gasifying apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently gasify a liquid material having complicated gasification characteristics as a material of a high dielectric substance and prevent clogging in an apparatus and a pipe arrangement, by providing a liquid material flow path, a gasification flow path and a heating mechanism, and causing the heat receiving area per unit liquid quantity of the gasification flow path to be not less than a specified quantity. SOLUTION: A material container 12 for housing a liquid material L and a material transportation tube 14 connected thereto are provided. Downstream of a flow controller 18 along the material transportation tube 14, a gasification preventing section 20 is provided. Just after the section 20 in the downstream, a gasifying section 22 for instantaneously gasifying the liquid material L by exposing the liquid material L to a high temperature and a low pressure is provided. Particularly, the gasifying section 22 has a heating section 36 of a jacket structure for housing a heat medium of a high temperature. In this heating section 36, the heat receiving area per unit liquid quantity is set to be not less than 2 (mm<2> /mm<3> ). Thus, it has a structure in which a fine tube for material transportation is inserted in a jacket 38.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vaporizer for use in, for example, a thin film vapor phase growth apparatus using a liquid as a raw material, and in particular, to vaporize a high dielectric or ferroelectric thin film material such as barium / strontium titanate. The present invention relates to a liquid material vaporizer suitable for the above.

[0002]

2. Description of the Related Art In recent years, the degree of integration of integrated circuits in the semiconductor industry has been remarkably improved, and research and development of DRAMs from the current megabit order to the future gigabit order have been conducted. As a dielectric thin film used for manufacturing a large-capacity element required for manufacturing such a DRAM, a silicon oxide film or a silicon nitride film having a dielectric constant of 10 or less, and tantalum pentoxide (Ta ₂ O) having a dielectric constant of about 20 are used. ₅ ) Instead of the thin film, a metal oxide thin film material such as barium titanate (BaTiO ₃ ) having a dielectric constant of about 300 or strontium titanate (SrTiO ₃ ) or barium strontium titanate (BST) is considered to be promising. I have. Further, ferroelectric thin film materials such as PZT, PLZT, and Y1 having a higher dielectric constant are also considered promising.

As a method for forming a film of such a material, chemical vapor deposition (CVD) is promising. In this case, a source gas is stably supplied to a substrate on which a film is to be formed in a film forming reaction tank. There is a need to. The raw material gas dissolves Ba (DPM) ₂ , Sr (DPM) _2, etc. which are solid at normal temperature, and furthermore, an organic solvent (for example, T
HF, etc.) is heated to evaporate. As a device for performing such vaporization, a technique is known in which a liquid raw material is once atomized by a spray nozzle or an ultrasonic vibrator and then sent to a high temperature region to be gasified.

[0004]

By the way, it is very difficult to stably vaporize the raw material gas of the above-mentioned high dielectric substance or ferroelectric substance. This is because the vaporization temperature and decomposition temperature of these raw materials are close, there is a difference between the vaporization temperature and the vaporization temperature of the organic solvent, the vapor pressure is very low,
This is because the raw material is liable to be deteriorated due to the presence of trace amounts of oxygen, water vapor, and the like.

For example, Ba (DPM) ₂ , Sr (DP
In the case of a liquid raw material in which M) ₂ is dissolved in THF, the liquid phase range of the solvent is the region shown in FIG. 23A, and the solid phase or liquid phase range of the raw material is (a + c). Therefore, when passing through the region (c) in order to vaporize the raw material in the region (a), only the solvent vaporizes and the raw material precipitates, blocking the passages and causing deterioration in quality due to concentration change. In this case, it is necessary to bring the liquid raw material to the high-temperature region at a stretch.

In some cases, a very small amount of raw material must be supplied depending on the object to be formed and the film forming conditions. At this time, if the vaporization is not performed well and the vaporized gas is sent to the film formation chamber in an unstable manner, the film formation has a serious adverse effect. Therefore,
In a vaporizer, it is necessary to perform control to a very small amount.

In the prior art, when atomizing using a spray nozzle, it is difficult to atomize while controlling a very small amount because the carrier gas is sent at a considerably high pressure. Further, when an ultrasonic vibrator is used, it is difficult to find a material that can withstand a high temperature close to the vaporization temperature, and stable vaporization cannot be performed. Further, it is preferable that the source gas is vaporized immediately before the reaction tank as much as possible to shorten the transport path in the gas phase, but it is difficult to make the apparatus compact since the vaporization is performed after atomization. Met. In addition, both require a large space for atomization and spraying, so that there is a problem that the raw material stays, and the deterioration of the raw material in that part is suppressed and the controllability of the raw material supply is poor.

The present invention efficiently vaporizes a liquid material having complicated vaporization characteristics, which is a material of a high dielectric substance or a ferroelectric substance, and controls a small amount of the liquid material with high precision, so that the vaporization in a vaporization apparatus or a pipe can be performed. It is an object to provide a compact vaporizer capable of preventing clogging.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an invention according to claim 1 is a liquid material vaporizer for vaporizing a liquid material and supplying it to a processing chamber. In the apparatus, a liquid material flow path for flowing a liquid material, a vaporization flow path downstream of the liquid material flow path, and a heating mechanism for heating the vaporization flow path, the vaporization flow path is a unit A liquid raw material vaporizer characterized by having a heat receiving area per liquid amount of 2 (mm ² / mm ³ ) or more.

[0010] In such a configuration, the heat receiving area per unit liquid amount is set to be sufficiently large, so that the temperature and pressure range in which the internal liquid raw material is heated at once and uniformly to decompose or degrade the raw material. A stable vaporization process is performed by passing through instantaneously. As the channel cross-sectional shape, a circle, an ellipse, a rectangle, an arbitrary polygon, and an arbitrary curved figure are appropriately used.

Preferably, the vaporization flow path is formed inside a thin tube. Thus, the above-described effects can be obtained with a simple structure, and clogging and the like are not easily caused, the manufacturing cost is low, and replacement at the time of maintenance is easy.

According to a second aspect of the present invention, the vaporizing flow path has an annular flow path having an annular cross section, and the inner member of the annular flow path has a notch along the flow direction, a heating mechanism, The liquid raw material vaporizer according to claim 1, further comprising: Thereby, the heat receiving area per unit liquid amount can be set sufficiently large, the distance from the heating wall surface to the farthest part of the liquid to be heated can be shortened, and even if the flow in the flow path is laminar, It achieves the three points of improving the vaporization characteristics by shortening the maximum distance transmitted by conduction and sufficiently increasing the cross-sectional area of the flow path, and has a relatively simple structure and low manufacturing and maintenance costs. Since the inner member has a cutout along the flow direction, the pressure can be reduced over the entire vaporizing portion, and since the heating member has a heating mechanism, heat can be applied to the inner member, The vaporization efficiency can be increased by heating the liquid source flow path from inside and outside.

Preferably, the vaporization flow path has a vaporization promoting region having a large heat receiving area per unit liquid amount and a pressure absorption region having a heat receiving area per unit liquid amount smaller than the vaporization promoting region. I do.

[0014] Preferably, the heating mechanism is formed so as to heat the annular flow path from inside and outside. Thus, the heat receiving area per unit liquid amount can be further increased, and the distance to the farthest part of the liquid to be heated can be shortened.

According to a third aspect of the present invention, there is provided a liquid material vaporizer for vaporizing a liquid material and supplying the liquid material to a processing chamber, wherein a liquid material flow path for flowing the liquid material and a downstream side of the liquid material flow path. Having a heating mechanism for heating the vaporization flow path, wherein the vaporization flow path has a maximum dimension of a distance from a shortest wall surface of each point in a cross section thereof of 2 mm or less. It is a liquid material vaporizer characterized by the following.

In this case as well, a circular, elliptical, rectangular, arbitrary polygonal, or arbitrary curved figure is appropriately used as the cross-sectional shape of the flow path. Accordingly, since the distance of the liquid source from the heating surface in the vaporization flow path is 2 mm or less at the maximum, even if the flow in the flow path is laminar, vaporization by heat conduction can be performed instantaneously. Preferably, the vaporization flow path is formed inside a thin tube.

According to a fourth aspect of the present invention, the vaporizing flow path has an annular flow path having an annular cross section, and the inner member of the annular flow path has a notch along the flow direction, a heating mechanism, The liquid raw material vaporizing apparatus according to claim 3, comprising: Thus, the pressure can be reduced over the entire vaporizing section and heat can also be applied to the inner member, so that the liquid material flow path can be heated inside and outside, and the vaporization efficiency can be increased. Preferably, the heating mechanism is formed so as to heat the annular flow path from inside and outside. Preferably, the vaporization flow path has a vaporization promoting region having a large heat receiving area per unit liquid amount, and a pressure absorption region having a heat receiving area per unit liquid amount smaller than the vaporization promoting region.

According to a fifth aspect of the present invention, there is provided a liquid raw material vaporizer for vaporizing a liquid raw material and supplying the liquid raw material to a processing chamber, wherein a liquid raw material flow path for flowing the liquid raw material and a downstream side of the liquid raw material flow path. A vaporizing channel, and a heating mechanism for heating the vaporizing channel, wherein the vaporizing channel has an enlarged portion whose cross-sectional area increases downstream. . As a result, the pressure in the vaporizing section is reduced by lowering the pipe resistance on the secondary side of each vaporizing point, and a pressure increase accompanying vaporization can be avoided, and efficient vaporization can be performed.

Preferably, the average divergence angle from the start point to the end point of the enlarged portion is equal to or less than 14 degrees in terms of the equivalent circular diameter. As a result, while avoiding a pressure increase due to vaporization,
Efficient vaporization can be performed while maintaining heat transfer in the vaporization section.

[0020] Preferably, the enlarged portion has two or more stages, the average divergence angle of the first stage is 5 degrees or less in terms of equivalent circular diameter, and the average divergence angle of the second stage is 14 degrees or less.
Preferably, the shape of the enlarged portion is such that its cross section is in a region between the quadratic curve and the 10th-order curve passing through the starting point P ₀ and the ending point P ₁ of the enlarged portion, and the spread angle at the base point is between 0 ° and 5 ° To be there.

Preferably, the cross-sectional shape of the enlarged portion is L
Is the length from the starting point of the enlarged portion to an arbitrary point, and r is L
Where r is the equivalent circle radius at the cross section at the point, C is an arbitrary constant, L ₀ is the starting point of the enlarged portion, b is the equivalent circle radius at the cross section of the starting point of the enlarged portion, and r ≧ C ₁ × (L + L ₀ ) ¹⁰ + B ₁ and in an area defined by r ≦ C ₂ × (L + L ₀ ) ² + b ₂ , and the angle between the tangent line at L ₀ and the line of r = b is set to 0 degree or more and 5 degrees or less. . Thereby, the most efficient vaporization can be performed as a shape formed by connecting the line ends smoothly in this region. Here, the equivalent circle radius refers to the radius of a circle having the same cross-sectional area as the cross-sectional area enclosed in one loop.

According to a sixth aspect of the present invention, there is provided a liquid material vaporizer for vaporizing a liquid material and supplying the vaporized liquid material to a processing chamber, wherein a liquid material flow path for flowing the liquid material and a downstream side of the liquid material flow path. A vaporizing flow path, and a heating mechanism for heating the vaporizing flow path, wherein the vaporizing flow path has an annular flow path having a circular cross section. .

According to a seventh aspect of the present invention, the annular flow path is provided along an outer pipe, such as a circular pipe or a rectangular pipe, having a single-loop cross-sectional flow path and near the center thereof. 7. The liquid raw material vaporizing apparatus according to claim 6, comprising a single or a plurality of core members, wherein the core member has a notch along a flow direction and a heating mechanism. By appropriately selecting the outer diameter of the core member, an annular flow passage having an appropriate gap is formed between the core member and the outer tube. Thus, the pressure can be reduced over the entire vaporizing section and heat can also be applied to the inner member, so that the liquid material flow path can be heated inside and outside, and the vaporization efficiency can be increased.

Preferably, the core member is movable in the axial direction of the outer tube. By moving the core member, it is possible to promote the detachment of the adhered substance and the like, and if it is used in common with a cleaning agent or the like, it is possible to clean the vaporized portion or the like without breaking the vacuum system.

Preferably, the core member can be substantially removed from the vaporization part by moving in the axial direction in the upstream direction of the flow while maintaining airtightness with the outside. , A solvent, a cleaning liquid, a carrier gas, and the like. As a result, it is difficult to flow a large amount of the cleaning liquid even if an excessive pressure is applied to the cleaning liquid because the clearance of the vaporization section is narrow. The washing can be performed, and the washing can be easily performed completely in a short time.

Preferably, the core member is moved in the axial direction while maintaining airtightness with the outside, so that the clearance between the outer tube of the vaporizing portion and the core member in the vaporizing portion is widened, and the solvent, solvent, cleaning liquid, carrier gas, etc. To reduce the pressure loss and allow a large amount of solvent, solvent, cleaning liquid, carrier gas and the like to flow easily. By moving the core member to the upstream side in the axial direction, the vaporized portion clearance can be increased. Further, when the taper of the vaporizing portion is reversed, the same effect can be obtained by moving the vaporizing portion to the downstream side.

Preferably, there is provided an inner heating means for heating the core member. This may form a flow path for the heat medium, or may be a simple type in which an electric heater or the like is embedded.

Preferably, the core member is formed with an internal flow path and a nozzle hole for introducing a predetermined fluid into the vaporizing section or the vaporizing preventing section. As a result, a solvent, a solvent, a carrier gas, a cleaning liquid, or the like is sprayed regularly or as needed for the purpose of promoting vaporization, preventing clogging, and cleaning the inside of the pipe.

According to an eighth aspect of the present invention, there is provided a liquid material vaporizer for vaporizing a liquid material and supplying it to a processing chamber, wherein a liquid material flow path for flowing the liquid material and a downstream side of the liquid material flow path are provided. And a heating mechanism for heating the vaporization flow path, the heating mechanism having a jacket formed surrounding the liquid material flow path and a heat medium contained in the jacket. It is a liquid raw material vaporizer characterized by the above-mentioned. With this, the entire heat inside the jacket can be made uniform by the convection effect of the heat medium by the fluid heat medium having a sufficient heat capacity, and local high and low temperatures can be prevented. It is possible to promote and prevent the deterioration of the raw material due to local high temperature.

Preferably, the jacket is provided with a heater for heating the heat medium. Preferably, a heat medium circulation path for supplying the heat medium is provided in the jacket. Thereby, forced convection occurs in the jacket, and more uniform heating can be performed.

According to a ninth aspect of the present invention, there is provided a liquid material vaporizer for vaporizing a liquid material and supplying the vaporized liquid material to a processing chamber, wherein a liquid material flow path for flowing the liquid material and a downstream side of the liquid material flow path. A vaporization channel, a heating mechanism for heating the vaporization channel, and a vaporization prevention unit having a vaporization prevention mechanism for preventing vaporization of the liquid source in the liquid source channel upstream of the heating mechanism. It is a liquid raw material vaporizer characterized by having. This prevents the liquid raw material on the upstream side of the heating mechanism from being decomposed or deteriorated under the influence of the vaporization flow path, thereby enabling smooth and high-quality vaporization.

Preferably, the heating mechanism has a jacket formed surrounding the vaporization flow path and a heating medium accommodated in the jacket. Preferably, the heating mechanism has a heating element arranged near the vaporization flow path.

Preferably, the vaporization preventing mechanism prevents the influence of heat of the vaporization mechanism from affecting the liquid material of the vaporization preventing section. Preferably, the vaporization prevention mechanism prevents the influence of the pressure of the vaporization mechanism from affecting the liquid material of the vaporization prevention section.

Preferably, the vaporization preventing mechanism has at least one of a throttle, an orifice, a check valve, and an on-off valve. Preferably, the vaporization prevention mechanism has a check valve, and in the check valve, a drive mechanism for pressing a valve body toward a valve seat is disposed on a primary side of the flow.

According to a tenth aspect of the present invention, in a liquid source vaporizing apparatus for vaporizing a liquid raw material and supplying the vaporized liquid raw material to a processing chamber, a carrier gas and a solvent are provided in a liquid flow path or a vaporized gas flow path through which the liquid raw material flows. A liquid source vaporizer, wherein a medium introduction flow path for flowing at least one of a solvent, a cleaning liquid, and the like is joined.

Preferably, the apparatus further comprises a vaporization prevention mechanism for preventing the vaporization of the liquid raw material in the liquid raw material flow path upstream of the heating mechanism for heating the liquid raw material, wherein the medium introduction flow path is provided. The liquid flow path or the vaporized gas flow path is merged before the mechanism. Preferably, the medium introduction flow path merges with the raw material flow path or the vaporization flow path between the vaporization prevention mechanism and the heating mechanism.

[0037] Preferably, the medium introduction flow path merges at the outlet of the vaporization flow path. When the carrier gas flows from the inlet of the vaporizing section, the flow path cross-sectional area is small, so that the absolute amount is limited. By flowing a large amount of the carrier gas at the portion where the cross-sectional area of the flow path is enlarged, the unvaporized portion that has not been vaporized in the vaporizing section can be vaporized, and the vaporization efficiency can be improved. Also, in the case of washing, when a washing solution or the like is allowed to flow only from above, a drift occurs when the cross-sectional area of the flow path is enlarged,
Although it is difficult to completely clean the unvaporized portion, according to the present invention, the cleaning becomes more complete by flowing a large amount of the cleaning liquid or the like where the cross-sectional area of the flow path is enlarged.

[0038] More preferably, the medium introduction flow path joins the vaporization flow path at the outlet of the vaporization flow path. Thus, the pipe can be installed from a place where the cross section of the flow path is enlarged, so that the pipe diameter can be increased and the flow rate can be increased. Further, since the pipe can be installed at the center of the vaporizing section, an even distribution flow can be achieved.

According to an eleventh aspect of the present invention, in a liquid source vaporizing apparatus for vaporizing a liquid source and supplying the same to a film forming chamber, a port from a vaporizing section outlet of a line through which a vaporized gas is sent to the film forming chamber is provided. It is a liquid raw material vaporizer characterized by having an uphill section. As a result, it is possible to prevent the unvaporized raw material that has not been completely vaporized in the vaporization section or the raw material that has been vaporized but recondensed and liquefied from flowing into the processing chamber.

According to a twelfth aspect of the present invention, there is provided a liquid source vaporizer according to any one of the first to eleventh aspects, and a film forming chamber disposed downstream of the liquid source vaporizer. It is a film forming apparatus.

[0041]

Embodiments of the present invention will be described below with reference to the drawings. The vaporizer of the present invention is a device that has a remarkable effect when, for example, a liquid raw material in which an organic metal compound such as titanium, barium, strontium, lead, zirconium, bismuth, tantalum, niobium, or lanthanum is dissolved in an organic solvent is vaporized. .

FIG. 1 is a diagram showing the general outline of a thin film vapor phase growth apparatus including a vaporizer of the present invention. In FIG.
Reference numeral 10 denotes a liquid material source, which has a material container 12 for accommodating the liquid material L, and a material transport pipe 14 connected thereto. The material pump 10 has a material pump 16 for pressure-feeding the liquid material and a precise flow control and pulsation. Is provided with a flow rate controller 18 for flattening.

A vaporization preventing section 20 is provided downstream of the flow controller 18 along the raw material transport pipe 14, and immediately downstream thereof, a vaporizing section for instantaneously vaporizing the liquid raw material L by exposing the liquid raw material L to high temperature and low pressure. 22 are provided. Vaporizer 22
Is connected to a source gas injection device 30 in a processing chamber 28 by a gas transport pipe 26 heated by a heat retaining heater 24.
The gas injection device 30 is connected to a reaction gas (oxidizing gas) pipe 32 having a heater and a flow controller.

The vaporizing section 22 in this embodiment has a heating section 36 having a jacket structure for accommodating a high-temperature heat medium so that a large amount of heat can be supplied stably. And
In the heating section 36, as shown in FIG. 2A, in order to set a large heat receiving area per unit liquid amount (heat receiving area ratio), a thin tube 14a for transporting the raw material is provided in a jacket 38.
Is inserted. As a heat medium, oil or the like having a large heat capacity is used, and as shown in FIG.
This is heated by a high-temperature heat exchanger 40 arranged in 8. In the vaporizing section 22, a low-pressure atmosphere is maintained by a vacuum pump 34 disposed downstream of the thin film vapor phase growth apparatus.

The structure of the heating unit 36 is shown in FIG.
As shown in FIG. 3A, the thin tube 14a is directly heated by the heater 42 without using the jacket structure. As shown in FIG.
May be heated. Further, as shown in FIG. 4, a tank 44 for heating the heat medium may be provided outside, and this may be connected to the jacket 38 via a pump 46 and a circulation path 48 to circulate the heat medium. Accordingly, sufficient heating of the vaporizing section 22 can be performed while minimizing the thermal effect on the vaporizing preventing section 20.

In this configuration, the heat receiving area ratio H ₁ , which is the heat receiving area per unit liquid amount, is such that the heat receiving area per unit length S = πd and the liquid volume V = πd ² , where d is the inner diameter of the thin tube 14a. Therefore, H ₁ ∝S / V = 4 / d, which is larger in inverse proportion to the diameter d. This diameter is 2m
If it is set to m or less, sufficiently rapid vaporization is performed, and good results can be obtained.

The vaporization preventing section 20 is for putting the liquid raw material L in a vaporization preparation state in which the liquid raw material L can be vaporized instantaneously in the vaporizing section 22 while suppressing its decomposition and deterioration.
The vaporization preventing section 20 includes a low-temperature heat exchanger 52 to which a fluid whose temperature is controlled is supplied from a constant temperature bath 50. Thereby, the raw material transport pipe 14 in the low-temperature heat exchanger 52, the check valve 5
4. The liquid material L is maintained at, for example, the temperature Ty at the point Y shown in FIG. The value Py is set so that the check valve 54 does not affect the negative pressure on the vaporizing section side.

In the vaporizer having such a configuration, the liquid raw material L stored in the raw material container 12 is sent to the flow controller 18 along the raw material transport pipe 14 by the raw material pump 16 and the flow rate is precisely controlled. At the same time, the pulsation is sent to the vaporization preventing section 20 after the pulsation is flattened. In the vaporization prevention unit 20, the temperature Ty and the pressure Py are maintained without decomposing or deteriorating, and easily shift to the vaporization temperature, and further flow into the vaporization unit 22.

The liquid raw material L that has flowed into the vaporizing section 22 flows into a heat exchanger 40 having a double cylindrical structure composed of a thin tube (capillary tube) 14 a and an outer tube (jacket) 38. Here, a large amount of heat flows through the thin tube wall having a large heat receiving area per unit amount of liquid by the high-temperature heat medium in the jacket 38, and the temperature rises instantaneously, and the pressure is reduced by the action of the vacuum pump 34 on the downstream side. Also drops sharply and evaporates in the process of reaching point Z in the evaporating region in FIG.

The low-temperature heat exchanger 52 of the vaporization prevention section 20 and the high-temperature heat exchanger 40 of the vaporization section 22 are adjacent to each other at a very small interval, and the temperature gradient in the raw material transporting path 14 is sharp. I have. Therefore, the liquid raw material L instantaneously passes through the region (c), is completely vaporized without deteriorating the raw material, and without solutes precipitating when the solvent is vaporized first. To the object W to be processed.

In this embodiment, the raw material transport path is connected to the thin tube 1
Was constructed by 4a _1, as shown in FIG. 2 (b), it may be formed as a flat rectangular pipe 14a _2, thereby, it is possible to increase the processing rate while obtaining the same heating effect. Although the above description deals with the case where the liquid raw material L and the raw material container 12 are of one type, the present invention is not limited to this. A plurality of raw materials can be guided from a plurality of raw material containers, mixed in a mixing container (not shown), and the mixed solution can be vaporized through the vaporization preventing section 20 and the vaporizing section 22 and supplied to the processing chamber. .

FIG. 5 (a) is a view showing a vaporizing apparatus according to another embodiment of the present invention, and has an enlarged portion 56 in the rear half portion where the inner diameter of the thin tube 14a of the vaporized portion 22 is enlarged.
Such an enlarged portion 56 is provided in order to avoid the liquid material L being heated and being partially vaporized, since the pressure is increased and the vaporization is difficult if the liquid material L has the same diameter. In addition, it also functions as a mechanism for suppressing the pressure loss of the vaporized gas to the gas transfer pipe and for smoothly expanding the temperature change due to adiabatic expansion. Therefore, the enlarged portion 56
Is preferably provided at a position where latent heat for vaporization starts after obtaining sensible heat up to the vaporization temperature in the linear portion, that is, a position where vaporization starts. If the diameter is increased too rapidly, the supply of heat from the thin tube wall becomes insufficient and the vaporization efficiency is rather lowered. Therefore, the angle θ of the enlarged portion 56 is set to 14 degrees or less, preferably 5 degrees or less. FIG. 5B shows two stages of enlarged portions 56a and 56b formed. The first stage θ ₁ is preferably 5 degrees or less, and the second stage θ ₂ is preferably 14 degrees or less.

FIG. 6 (a) shows a configuration in which the enlarged portion 56c has a curved cross-sectional shape that continuously increases in diameter. In this way, by increasing the diameter stepwise or continuously, it is possible to prevent a rapid change in pressure and perform highly efficient vaporization. In this embodiment,
The cross-sectional shape of the enlarged portion is in a region (a hatched region in FIG. 6A) between the quadratic curve and the 10th-order curve passing through the start point P ₀ and the end point P ₁ of the enlarged portion. That is, in FIG. 6 (a), the curve C _{1 is, (r-r 0) /} (r 1 -r 0) = [(L-L 0) / (L 1 -L
_0)] ^2, curve C _{2 is, (r-r 0) /} (r 1 -r 0) = [(L-L 0) / (L 1 -L
₀ )] is ¹⁰ . The spread angle θ _{0 at} the starting point P ₀ is shown in FIG.
As shown in (b), the angle is in the range of 0 <θ ₀ <5 degrees, and the enlarged portion is smoothly continuous. In this embodiment, the cross section is circular, but the shape can be set similarly for an ellipse, a rectangle, and the like. In that case, the equivalent circular radius is used as r instead of the actual radius. This is given by r = (A / π) ^1/2 where A is the cross-sectional area of the portion.

FIG. 7 shows another embodiment of the present invention, and explains a configuration for preventing the influence of the pressure of the vaporizing section 22 from being applied to the vaporizing preventing section 20. In FIG. 7 (a), a narrow throttle 58a having a smaller diameter is provided between the vaporizing section 22 and the vaporization preventing section 20,
Further, in FIG. 7B, an orifice 58b is provided instead of the throttle tube. Such throttle portions 58a, 58b
It will not be necessary to explain that acts to suppress the influence of the pressure acting on the vaporization preventing section 20 by the vaporizing section 22. In any of the embodiments, the check valve 60 is provided on the upstream side of the vaporization preventing section 20, and the same effect can be obtained by setting this to an appropriate value.

FIG. 8A shows another embodiment of the present invention, in which a non-return valve 62 is provided in the thin tube 14a in the low-temperature heat exchanger 52 in the vaporization preventing section 20. . As shown in FIG. 8B, the check valve 62 is
A spring 66 for urging the valve 4 is provided on the upstream side of the flow rate, and the valve body 64 is pressed against the valve seat 68 by using the tensile force of the expanded spring 66. This is because, in the check valve 62a using the pressing force of the compressed spring as in the embodiment shown in FIG. 8C, the spring is located downstream of the valve body 64, and the liquid raw material L is placed in this portion. This is an improvement in that the stagnant flow is likely to occur in the portion of the vaporization section 22 that is susceptible to thermal and pressure influences. The configuration shown in FIG. 8A or 8B prevents such stagnation. As a result, deterioration of the liquid raw material L can be prevented.

FIG. 9 (a) shows still another embodiment of the present invention.
And a core member 7 arranged with a small gap inside the core member 7
2, and has a ring-shaped cross section as shown in FIG. In this case, assuming that the outer diameter of the core member 72 is d ₁ and the inner diameter of the outer tube 70 is d ₂ , a heat receiving area ratio H ₂ , which is a heat receiving area per unit liquid amount, is a heat receiving area S = πd ² and a volume V = proportional to the ratio of ^{_{π (d 2 2 -d 1 2}} ) / 4, H 2 αS / V = 4d 2 / (d 2 2 -d 1 2) and composed. Here, since d ₂ ≒ d ₁ , H ₂ ∝S / V ≒ 2 / (d ₂ -d ₁ ), which increases substantially in inverse proportion to the diameter difference (d ₂ -d ₁ ). This means that the vaporization efficiency can be higher than that of the simple thin tube 14a in FIG. 1, while maintaining the cross-sectional area of the flow path and maintaining the amount of vaporization. FIG. 9B shows the enlarged portion as 2
This corresponds to FIG. 5B provided at the stage.

FIG. 11 shows a case where the core member is provided only in the vaporizing section 22. FIG. 11A shows an example of a straight core member 72a.
(B) shows an example in which a core member 72b having a conical portion is used. In the configuration shown in FIG. 11B, the cross-sectional area of the flow path is enlarged without increasing the width of the flow path, and therefore, without increasing the heat receiving area ratio, thereby suppressing the increase in pressure. And efficient vaporization is performed.

FIG. 12A shows a modification in which the shape of the core member is changed. The core member has a cutout along the flow direction. The core member 72h of FIG. 12B has a sector-shaped notch 73a having a predetermined central angle in a cross section,
FIG. 12C shows an example of a tubular core member 72i in which a cutout 73b opening inward is formed. As a result, a portion (a vaporization promoting region) A that forms a narrow gap with the heating surface in each cross section of the vaporizing section 22 and a portion (a pressure absorption region) B that forms a wider flow path are formed. Even if rapid vaporization occurs in the promotion region A, the pressure increase is absorbed in the pressure absorption region B, and the pressure can be reduced over the entire vaporization section, so that the vaporization efficiency can be improved.

FIG. 13 shows a structure in which a tube 74 is further inserted into the core member 72c to form a heating medium flow path, and the liquid raw material L flowing through the annular flow path is heated from inside and outside. In this example, in order to prevent the core member 72c from interfering with the heat medium flow path, the raw material transport path 14 from the vaporization preventing section 20 to the vaporizing section 22 is bent by 90 degrees. In this case, the heat receiving area ratio H ₃ is, as shown in FIG. 14A, a heat receiving area S = π (d ₂ + d ₁ ) and a volume V = π (d
Proportional to the ratio of ^{_{2 2 -d 1 2) / 4}} , H 3 αS / V = 4 (d 2 + d 1) / (d 2 2 -d 1 2) = 4 / (d 2 -d 1) Thus, it can be seen that the vaporization efficiency is doubled as compared with the case of FIG. FIG. 14B shows the outer tube 70 and the core member 72d formed in a rectangular shape. This makes it possible to increase the processing flow rate while obtaining the same heating effect.

FIG. 15 shows another embodiment in which the liquid raw material L flowing in the annular flow passage is heated from inside and outside. Here, a heater 76 and a temperature sensor 78 are embedded inside a core member 72d of the vaporizing section 22. I have. In this example, the core member 72d also passes through the vaporization preventing section 20, but a heat insulating material 80 is disposed between the vaporizing section 22 and the vaporization preventing section 20 of the core member 72d to prevent mutual heat transfer. ing. In this embodiment, electric wiring may be provided instead of piping, so that the configuration is simplified and fine temperature control can be performed based on the value detected by the sensor 78.

FIG. 16A shows a modification in which the shape of the core member incorporating the heater of the embodiment of FIG. 15 is changed, and the core member has a cutout along the flow direction. . The core member 72j in FIG. 16B has a fan-shaped notch 73a having a predetermined central angle in the cross section, and is formed as shown in FIG.
(C) shows an example of a tubular core member 72k having a notch 73b opening inside. As a result, a vaporization promoting region A and a pressure absorbing region B are formed, and even if vaporization occurs in the vaporization promoting region A by heating the liquid material flow path from inside and outside, the pressure increase is absorbed in the pressure absorbing region B, Since the pressure can be reduced over the entire vaporizing section, the vaporization efficiency can be improved.

FIG. 17 shows still another embodiment of the present invention, in which a core member is configured so as to be freely inserted into and removed from a raw material transport pipe. In the embodiment of FIG. 17A, the vaporization preventing section 20 and the raw material transport pipe 14 of the vaporization section 22 are connected at right angles, and the outer pipe 82 constituting the vaporization section 22 is open at the upper part. A core member 72e having a large-diameter portion 84 of a size to be fitted is inserted. On the outer peripheral surface of the large-diameter portion 84, a seal O for maintaining airtightness with the outer tube 82 is provided.
A ring 86 is disposed, and a core member 72 is provided on the top of the outer tube 82.
A drive device 88 for driving e vertically is provided.

In this embodiment, the outer tube 82 and the core member 7
When clogging or the like occurs in the minute annular flow path between 2e or when there is a possibility of such clogging, the following cleaning process is performed. That is, by switching a predetermined valve, for example, a cleaning agent (solvent) flows through the raw material transport pipe 14, and the downstream of the vaporizer is connected to the drain. Then, the driving device 88 is operated while flowing the cleaning agent to move the core member 72e up and down.
As a result, without destruction of the vacuum system of the entire device,
Prevention of clogging or elimination of clogging can be achieved.

FIG. 17B shows an example in which the vaporization preventing section 20 and the vaporizing section 22 are connected in series. In this case, the thickness of the core member 72f in a portion corresponding to the throttle portion 58a between the vaporization preventing portion and the vaporization portion may be changed, and the gap between the throttle portions may be adjusted by moving the core member up and down. it can. In any of the above cases, a structure may be adopted in which the core member is heated as in the previous case.

FIG. 18 shows still another embodiment of the present invention. In the embodiment shown in FIG.
An extraction area 90 for completely extracting the core member 72m from the vaporization section 22 is provided in an airtight manner with the outside. A core member 72 m is provided above the extraction region 90.
Is provided via a shaft 91. The driving device 88 is separated from the extraction area 90 by a bellows 89. Large diameter portion 8 of core member 72m
4 is provided with an O-ring 86 for partitioning the extraction area 90 and the vaporizing section 22 when the apparatus is in the lowered position.
A cleaning liquid pipe 93 for supplying a cleaning liquid is provided above the drawing area 90.

In the embodiment having such a configuration, in the vaporization step, the core member 72m is lowered to insert the core member 72m into the vaporization pipe 82 as shown in FIG. It is performed in the state where it is formed. When washing is performed,
As shown in FIG. 8B, the core member 72m is completely withdrawn from the vaporizing section 22 and the cleaning liquid pipe 93 in the withdrawal region 90 is removed.
Is supplied with a cleaning solution Cl. This cleaning liquid first cleans the core member 72m, then cleans the inner surface of the vaporization tube 82, and is discharged to the drain below the vaporization section.

Here, the core member 72m is connected to the vaporizing pipe 82.
From the core member 72m and the vaporizing pipe 82.
Are exposed to a large space, and a large amount of the cleaning liquid Cl can be supplied thereto at high pressure. Therefore, a significantly higher cleaning effect and cleaning efficiency can be obtained as compared with the case where cleaning is performed while maintaining a narrow gap.

FIG. 19 (a) shows a modification of the embodiment of FIG. 18, in which the core member 72m can enter and exit both the vaporization preventing section 20 and the vaporizing section 22 which are arranged in series. I have. In this example, the core member 72m has portions 75a and 75b of different diameters connected via a tapered portion 75c that narrows toward the distal end. The internal flow paths 82a, 82b, 82c of the vaporization preventing section 20 and the vaporization section 22 are formed to have a cross-sectional shape corresponding to the above-described shape of the core member 72m. Similarly, a driving device 88 is provided above the extraction area 90 provided on the top of the vaporization preventing section 20.

In this embodiment, in the cleaning step, similarly, as shown in FIG.
2 and by performing the same steps as in FIG. 18 (b). By flowing the cleaning liquid Cl from the cleaning liquid pipe 93, the internal flow paths 82a, 82b, and 82c of the vaporization preventing section 20 and the vaporizing section 22 are simultaneously cleaned. Core member 7
By providing the portions having different diameters at 2 m, it is not necessary to remove all the core members from the vaporization preventing section 20 to form a cleaning space having an appropriate width for flowing the cleaning liquid. Therefore, the required stroke of the core member 72m can be shortened and the size of the device can be reduced in the vaporizer of the serial arrangement type.

FIG. 20 is also related to the embodiment of FIG. 18, and FIG. 20 (a) shows the tapered portions 94a, 94a having the same taper in both the vaporizing tube 82a and the core member 72p inserted therein. 94b respectively.
In this embodiment, the diameter is reduced toward the downstream, but the configuration may be reversed. In this embodiment, even if the core member 72p is not completely extracted from the vaporization part 22, if the core member 72p is pulled out to some extent, the core member 72p and the vaporization pipe 82a are removed.
A certain gap is formed between them, and a certain flow rate of the cleaning liquid Cl is caused to flow in, so that efficient cleaning can be performed.

FIG. 20B shows the tapered portions 94a and 94b.
Are formed from the vaporization preventing section 20 to the vaporizing section 22. The core member 72q has a configuration in which a heater is built in a portion corresponding to the vaporizing section 22. In this embodiment, since the core member 72q has a taper including the vaporization preventing section 20, the distance for drawing out the core member 72q can be further reduced.

FIG. 21 shows a flow path 90 inside a core member 72g.
And a nozzle hole 9 in the surface of the core member 72g.
2 is formed. Therefore, a predetermined fluid can be mainly supplied to the vaporizing section 22 through the internal flow path 90 and the nozzle holes 92 constantly or as needed. The purpose of such treatment is usually to promote vaporization and prevent clogging. In any case, a carrier gas, the same solvent as the raw material or an appropriate solvent, a cleaning agent, etc., are supplied.

For example, a description will be given of a process of injecting a carrier gas in this apparatus to promote vaporization. This is performed based on the following equation, which is a condition under which the entire amount of the liquid raw material L is vaporized. PVM / PT ≧ QM / (QM + QSV + QCG) where PVM is the vapor pressure of the raw material at that temperature, PT is the total pressure of the vaporizing section, QM is the amount of the metal raw material, QSV is the amount of the solvent, QCG
Indicates the amount of the carrier gas. PVM is a function of temperature,
It is constant if the temperature is constant. Therefore, if a solvent or a carrier gas can be supplied from the nozzle hole 92 of the core member 72g without changing the temperature of the vaporizing section 22, vaporization can be promoted.

The carrier gas, the solvent, the solvent, and the cleaning liquid may be injected from the upstream side of the vaporization preventing section 20, the inlet of the vaporizing section, or the space between the vaporization preventing mechanism and the vaporizing section. The main purpose is to clean the secondary side of the vaporizer. In this case, when the liquid is injected at the outlet of the vaporizer, a large amount of the cleaning liquid can be flowed, so that the effect is large.

FIG. 22 shows such an embodiment, which is also formed entirely as a double tube having a jacket structure for introducing a heat medium, and has a tapered downstream side of a thin tube 70 constituting the vaporizing section 22. The medium-introducing tube 95 is provided in the large-diameter portion 70b downstream of the large-diameter portion 70a so as to open from the lower portion of the large-diameter portion 70a so as to face the outlet of the thin tube 70. The medium introduction pipe 95 is connected to a source such as a carrier gas, a solvent, a solvent, and a cleaning liquid via an on-off valve 96. Outgoing pipe 9 for outgoing vaporized raw material
Reference numeral 7 denotes an opening in the large-diameter portion 70b further downstream than the opening of the medium introduction pipe 95, which is connected to a downstream film forming chamber or the like via an upwardly inclined portion 98 extending upward from the horizontal. I have. The on-off valve 99a is provided below the large diameter portion 70b.
, A bypass pipe 99 is provided.

In this apparatus, during the vaporization step, an amount of carrier gas corresponding to the amount of the raw material introduced through the medium introduction pipe 95 is caused to flow from the side facing the raw material to the vaporizing region. Thereby, the carrier gas is not restricted by the cross-sectional area of the flow path as compared with the case where the carrier gas flows from the inlet side of the vaporization unit,
Since a large amount can be flown to an appropriate predetermined vaporization region or a downstream portion thereof, and the unvaporized portion in the vaporization section 22 can be vaporized, the vaporization efficiency can be improved.

In the cleaning step between the vaporizing steps, a solvent, a solvent, a cleaning liquid and the like are introduced from the medium introducing pipe 95, and are led out from the bypass pipe 99 and the like to efficiently clean the vaporizing section 22. Do. Of course, these may be introduced simultaneously from the upstream side. Accordingly, even if the cleaning liquid or the like is supplied only from the upstream, uneven flow occurs and the enlarged-diameter portion 70a having a flow path cross-sectional area that is difficult to be cleaned can be more completely cleaned by flowing a large amount of the cleaning liquid or the like.

In this embodiment, since the rising pipe 98 is provided in the outlet pipe 97, the unvaporized raw material and the raw material once vaporized but recondensed and liquefied are trapped in the rising pipe 98. You. Therefore, it is possible to prevent these liquid-state raw materials from flowing into a downstream film forming chamber or the like.

[0079]

As described above, according to the present invention, since the heat receiving area per unit liquid amount is set to be sufficiently large, the liquid material inside is heated at once and uniformly.
A stable vaporization process is performed by instantaneously passing through a temperature / pressure region where the raw material is decomposed or altered. Therefore, it is possible to efficiently vaporize a liquid material having a complicated vaporization characteristic, which is a material of a high dielectric or a ferroelectric, and to precisely control a small amount to prevent clogging in a vaporizer or a pipe. Thus, a compact vaporizer can be provided.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of a thin film vapor deposition apparatus using a vaporizer according to the present invention.

FIG. 2A is a cross-sectional view of a heating mechanism of a vaporizing section of the apparatus of FIG. 1, and FIG. 2B is another embodiment of a similar part.

FIGS. 3A and 3B are schematic views of still another embodiment of the heating mechanism of the vaporizing section.

FIG. 4 is a schematic view of still another embodiment of the heating mechanism of the vaporizing section.

5 (a) and 5 (b) are cross-sectional views schematically showing other embodiments of the vaporizer of the present invention.

6 (a) and 6 (b) are cross-sectional views schematically showing other embodiments of the vaporizer of the present invention.

FIGS. 7A and 7B are cross-sectional views schematically showing another embodiment of the vaporizer of the present invention.

8 (a) and 8 (b) are cross-sectional views schematically showing another embodiment of the vaporizer of the present invention, and FIG. 8 (c) is a view of still another embodiment.

FIGS. 9A and 9B are cross-sectional views schematically showing another embodiment of the vaporizer of the present invention.

FIG. 10 is a sectional view taken along line AA of FIG. 9 (a).

FIGS. 11A and 11B are cross-sectional views schematically showing another embodiment of the vaporizer of the present invention.

12 (a) and (b) or (c) are cross-sectional views schematically showing another embodiment of the vaporizer of the present invention.

FIG. 13 is a sectional view schematically showing another embodiment of the vaporizer of the present invention.

FIG. 14A is a sectional view taken along line AA in FIG.
(B) is sectional drawing of the same location of other embodiment.

FIG. 15 is a sectional view schematically showing another embodiment of the vaporizer of the present invention.

16 (a) and (b) or (c) are cross-sectional views schematically showing another embodiment of the vaporizer of the present invention.

17 (a) and (b) are cross-sectional views schematically showing another embodiment of the vaporizer of the present invention.

18 (a) and (b) are cross-sectional views schematically showing another embodiment of the vaporizer of the present invention.

FIGS. 19A and 19B are cross-sectional views schematically showing another embodiment of the vaporizer of the present invention.

20 (a) and (b) are cross-sectional views schematically showing another embodiment of the vaporizer of the present invention.

FIG. 21 is a sectional view schematically showing another embodiment of the vaporizer of the present invention.

FIG. 22 is a sectional view schematically showing another embodiment of the vaporizer of the present invention.

FIG. 23 is a graph showing characteristics of a raw material to be vaporized.

[Explanation of symbols]

 L Liquid source 14 Liquid source flow path 14a Thin tube 20 Vaporization prevention unit 22 Vaporization unit 28 Processing chamber 30 Gas injection device 36 Heating unit 38 Jacket 40 High temperature heat exchanger 42 Heater 48 Circulation path 50 Constant temperature bath 52 Low temperature heat exchanger 54 Non-return Valve 56 Enlarged portion 66 Spring 68 Valve seat 70 Outer tube 70a Large diameter portion 70b Large diameter portion 72 Core member 73a, 73b Notch

Claims (12)

[Claims] 1. A liquid source vaporizer for vaporizing a liquid source and supplying it to a processing chamber, comprising: a liquid source channel for flowing the liquid source; a vaporization channel downstream of the liquid source channel; A heating mechanism for heating the vaporization flow path, wherein the vaporization flow path has a heat receiving area per unit liquid amount of 2 (m
m ² / mm ³ ) or more. 2. The vaporization flow path has an annular flow path having a circular cross section, an inner member of the annular flow path has a cutout along a flow direction, and has a heating mechanism. The liquid raw material vaporizer according to claim 1, wherein: 3. A liquid raw material vaporizer for vaporizing a liquid raw material and supplying it to a processing chamber, comprising: a liquid raw material flow path for circulating the liquid raw material; a vaporization flow path downstream of the liquid raw material flow path; A heating mechanism for heating the vaporization flow path, wherein the vaporization flow path has a maximum dimension of a distance from a shortest wall surface at each point in a cross section of the vaporization flow path being 2 mm or less. 4. The vaporization flow path has an annular flow path having a circular cross section, an inner member of the annular flow path has a cutout along a flow direction, and has a heating mechanism. The liquid raw material vaporizer according to claim 3, wherein: 5. A liquid raw material vaporizer for vaporizing a liquid raw material and supplying it to a processing chamber, comprising: a liquid raw material flow path through which the liquid raw material flows; a vaporization flow path downstream of the liquid raw material flow path; A heating mechanism for heating the vaporization flow path, wherein the vaporization flow path has an enlarged portion whose cross-sectional area increases toward the downstream side. 6. A liquid raw material vaporizer for vaporizing a liquid raw material and supplying the vaporized liquid raw material to a processing chamber, comprising: a liquid raw material flow path for flowing the liquid raw material; a vaporization flow path downstream of the liquid raw material flow path; A heating mechanism for heating the vaporization flow path, wherein the vaporization flow path has an annular flow path having a circular cross section. 7. The annular flow path includes an outer pipe having a single loop shape such as a circular pipe or a rectangular pipe, and one or more core members provided along the vicinity of the center of the outer pipe. 7. The liquid raw material vaporizer according to claim 6, wherein the core member has a cutout along the flow direction and has a heating mechanism. 8. A liquid raw material vaporizer for vaporizing a liquid raw material and supplying the vaporized liquid raw material to a processing chamber, comprising: a liquid raw material flow path for flowing the liquid raw material; a vaporizing flow path downstream of the liquid raw material flow path; A heating mechanism for heating the vaporization flow path, wherein the heating mechanism has a jacket formed surrounding the vaporization flow path, and a fluid heat medium contained in the jacket. Raw material vaporizer. 9. A liquid raw material vaporizer for vaporizing a liquid raw material and supplying it to a processing chamber, comprising: a liquid raw material passage for flowing the liquid raw material; a vaporizing flow passage downstream of the liquid raw material flow passage; A heating mechanism for heating the vaporization flow path, comprising a vaporization prevention unit having a vaporization prevention mechanism for preventing vaporization of the liquid raw material in the liquid raw material flow path upstream of the heating mechanism. Liquid raw material vaporizer. 10. A liquid material vaporizer for vaporizing a liquid material and supplying it to a processing chamber, wherein at least one of a carrier gas, a solvent, a solvent, and a cleaning liquid is provided in a liquid channel or a vaporized gas channel through which the liquid material flows.
A liquid raw material vaporizer, wherein a medium introduction flow path for flowing a stream is merged. 11. A liquid source vaporizer for vaporizing a liquid source and supplying it to a film formation chamber, wherein a port from a vaporization section outlet of a line through which a vaporized gas is sent to the film formation chamber has an upward slope. A liquid raw material vaporizer. 12. A film forming apparatus, comprising: the liquid source vaporizing apparatus according to claim 1; and a film forming chamber disposed downstream of the liquid source vaporizing apparatus.