JPH11128719A - Apparatus for vaporizing solution and apparatus for producing membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce gas having the same composition as that of a fed solution by vaporizing the solution in a steady state, particularly the one which includes a solute hard to vaporize, thermally unstable, and in some coses is a solid. SOLUTION: The apparatus comprises a solution-feeding part 14 for feeding a solution, a solution-vaporizing part 16 for vaporizing the solution fed by the solution-feeding part 14, and a gas-removing part 18 for removing vaporized gas. The solution-feeding part 14, the solution-vaporizing part 16, and the gas- removing part 18 comprise being along a channel in which liquid or gas continuously flows, have a temperature gradient by which temperature becomes higher from the solution-feeding part 14 to the gas-removing part 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solution vaporizer for vaporizing a solution containing a solvent and a solute and taking out the solution as a gas having the same composition as the supplied solution, and a film formation including such a solution vaporizer. Related to the device.

[0002]

2. Description of the Related Art An example of a conventional solution vaporizer is one in which a solution placed in a container is heated to evaporate the solution. Another example is to evaporate a heated liquid by blowing it out of a container in a mist state to increase the surface area.

[0003]

When a solution is heated to a constant temperature to evaporate it into a gas, the solvent and the solute have different evaporation temperatures, so that the composition of the supplied solution and the composition of the evaporated gas are different. In general, there will be different equilibrium relationships. For this reason, if the solution is continuously vaporized at a constant temperature, the concentration of the hardly evaporable component in the solution will continue to increase. Therefore, in the former method, components that are difficult to evaporate accumulate in the container, and the solution cannot be vaporized at a predetermined temperature. As described above, it is difficult to completely evaporate the solvent and the solute in the conventional vaporizer kept at a constant temperature, and to make a steady state.

[0004] The concentration of the supplied solution is different from the concentration of the gas taken out by evaporation. When the solute is a solid, for example, the pipe or the like may be pinched and closed. On the other hand, in the latter case, the temperature of the particles of the fine solution that has turned into a mist decreases due to the heat of vaporization, and the components that are also difficult to evaporate remain without being vaporized, and it is difficult to vaporize the entire supplied solution. . In each case, it is possible to vaporize all components of the solution by heating the solution to a very high temperature, but in the case of solutions containing thermally unstable substances, the solution may be heated to an excessively high temperature. Heating could not be performed, and the above-mentioned problems could not be solved by the conventional solution vaporizer.

[0005] Therefore, in a film forming apparatus using a conventional solution vaporizer, it has been demanded to be able to form a more uniform film. The object of the present invention is a solution,
In particular, a solution vaporizer and a film forming apparatus that constantly vaporize a solution containing a solute that is hard to evaporate and are thermally unstable and, in some cases, a solid, to produce a gas having the same composition as the supplied solution, are provided. To provide.

[0006]

A solution vaporizer according to the present invention comprises: a solution supply unit for supplying a solution; a solution evaporation unit for evaporating the solution supplied by the solution supply unit; and a gas for removing the evaporated gas. A solution supply unit, the solution evaporation unit, and the gas removal unit are located in a flow path in which a liquid or a gas continuously flows, and the temperature is increased from the solution supply unit toward the gas removal unit. It is characterized by having a temperature gradient that increases.

In this configuration, since a temperature gradient is formed such that the temperature increases from the solution supply section toward the gas take-out section, the solution starts to evaporate at a temperature that is a position just before the solution evaporation section, and The readily evaporable components in the solution begin to evaporate immediately, but the hardly evaporable components in the concentrated solution are not immediately evaporated, so that the concentration of the hardly evaporable components increases. Since the solution is continuously supplied from the solution supply section toward the gas take-out section, the solution in which the concentration of the component that is difficult to evaporate becomes high advances from the position before the above to the solution evaporation section. Since the temperature of the solution evaporating section is higher than the temperature at the position where the evaporation starts first, it is possible to evaporate even a solution having a high concentration containing a large amount of components that are difficult to evaporate. In this way, all the supplied solutions are evaporated, and the composition of the gas obtained by the evaporation becomes the same as the composition of the supplied solution.

Preferably, the solution vaporizer is constituted by a tube, and a cross-sectional area of the tube is such that a linear flow rate at which liquid flows from the solution supply section to the solution evaporation section is equal to the solution supply section and the solution evaporation section. This is sufficiently faster than the diffusion rate of the solute due to the difference in the concentration of the solution generated between. In addition, the gas outlet is heated, and the heat is radiated from the solution supply unit toward the gas outlet to form the temperature gradient.

A heater is attached to the gas outlet. Further, the gas extracting section is heated by irradiating the gas extracting section with an electromagnetic wave. Further, the solution vaporizer may be composed of a pipe branched from a common solution supply section to a plurality of solution evaporation sections and a gas extraction section.

Further, the present invention provides a film forming apparatus including the above-described solution vaporizer. In this film forming apparatus, an excellent heart film having a uniform component can be formed.

[0011]

FIG. 1 is a diagram illustrating the principle of the present invention. The solution supply device 10 includes a tube 12 that provides a continuous flow path.
In the drawing, the solution S is supplied from the right end side of the tube 12 and is taken out as gas G from the left end side. That is, the solution supply device 10 includes a solution supply unit 14 that supplies the solution, a solution evaporation unit 16 in which the solution supplied by the solution supply unit 14 evaporates, and a gas extraction unit 18 that extracts the evaporated gas.

A heater 20 is attached to the gas outlet 18. The gas extraction section 18 is heated by the heater 20.
Is transferred to the solution supply 14 by heat conduction through the tube 12. The heat is conducted in the tube 12 and is radiated from the tube 12, so that a temperature gradient as shown in FIG. 2 is created. In FIG. 2, X indicates the gas extraction unit 18, Y indicates the solution evaporation unit 16, and Z indicates the solution supply unit 14. The temperature of the solution supply unit (Z) 14 is T
₁ , the temperature of the solution evaporator (Y) 16 is T ₂ ,
Temperature of the gas extraction unit (X) 18 is T _3. Here, there is a relationship of T ₃ > T ₂ > T ₁ . T ₀ is the temperature at which vaporization of the solution starts, and T ₂ > T ₀ > T ₁ .

FIG. 3 shows the concentration distribution of the solution in the tube 12 including the solution supply section (Z) 14, the solution evaporation section (Y) 16, and the gas extraction section (X) 18. Solution supply unit (Z) 14
The concentration of the solution is C _1, the concentration of the solution of the solution evaporation portion (Y) 16 is C _3. The cross-sectional area of the tube 12 constituting the solution vaporizer 10 is determined by the linear flow rate at which the liquid flows from the solution supply unit 14 to the solution evaporation unit 16 and the concentration difference of the solution generated between the solution supply unit 14 and the solution evaporation unit 16. Is sufficiently faster than the diffusion rate of the solute. Also, the linear flow rate of the solution must be slow enough so that the following evaporation occurs.

FIG. 4 shows the general relationship of the vapor-liquid equilibrium of a binary solution. And a gas take-out portion located on the left end side of the tube 12 in FIG. 1 the pressure (X) 18 is constant, the solution containing the high-boiling substances in a concentration C ₁ is supplied to the solution supply unit (Z) 14. This solution begins to vaporize when the temperature of the solution reaches T ₀ . If heating is continued under these conditions without moving the solution, the resulting gas will have a high-boiling substance concentration of C ₂ . That is, the concentration C ₂ of the resulting gas is different from the concentration C ₁ of the supplied solution, part of the high boiling material is not vaporized.

In the present invention, since there is a temperature gradient as described above and the solution is flowing, the concentration of the remaining solution partially evaporated becomes higher than C ₁ , and as shown in FIG. Moving. As a result, the boiling point of the solution having a higher concentration increases, and the solution can be further evaporated at a high temperature portion. As a result, the concentration of the unvaporized solution becomes even higher,
The liquid level further moves to the left in FIG. Eventually, the concentration of the solution became C _3, the temperature becomes T _2. FIG. 3 is a diagram showing the concentration distribution of the solution in such a tube. The concentration of the gas obtained in this case is C ₁ becomes, which is the same as the concentration C ₁ of the solution fed.

FIG. 5 is a view showing a modification of the solution supply device 10. As shown in FIG. The solution supply device 10 includes a branch pipe 22. The branch pipe 22 is a pipe branched from a common solution supply unit 14 to a plurality of solution evaporation units 16 and a gas extraction unit 18. A heater 20 is attached to each gas outlet 18. The operations of the solution supply unit 14, the solution evaporation unit 16 and the gas take-out unit 18 are the same as those of the above embodiment. As described above, when the branch pipe is used, more solution can be vaporized at the same time. Note that a structure having a plurality of holes may be used instead of the branch pipe 22.

FIG. 6 is a diagram showing an embodiment of a CVD apparatus including the solution vaporizer 10. The CVD apparatus 30 includes a reaction tube 32 and a holder 36 that supports, for example, a semiconductor substrate 34.
And an electric furnace 38 for heating a chamber inside the reaction tube 32 and a pump 40 for bringing the reaction tube 32 into a vacuum atmosphere. The solution vaporizer 10 is attached to the reaction tube 32 and vapor-deposits the gas extracted from the solution vaporizer 10 on the substrate 34 to form a thin film on the substrate 34. The solution vaporizer 10 is supplied with a solution from a solution container 42 by a pump 44.

FIG. 7 is a view showing an example in which the solution vaporizer 10 is attached to a reaction tube 32. A stainless steel cap 46 is attached to the open end of the reaction tube 32, and the solution vaporizer 10 (tube 12) is air-tightly attached to the cap 46. The heater 20 is attached to the tip of the tube 12 located inside the reaction tube 32. This heat source creates a temperature gradient in the tube 12. The inner diameter of the tube 12 is 0.1 mm and the outer diameter is 6
mm.

When a Cu thin film is formed on the substrate 34, VEMS (vinyltrimethylsilane) is used as a solvent, and about 95 to 50% of CuHFAVTMS is added to the solute.
(Hexafluoroacetonate, vinyltrimethylsilane copper) is used as a raw material. In this case, the pressure in the reaction tube 32 is set to 300 mmTorr, and the temperature of the substrate 34 is set to 170 mmTorr.
C. and the temperature of the heater 20 is 70 C. In this condition,
The solution can be constantly vaporized at a flow rate of 0.1 g / min. 300 nm for a 6-inch substrate 34
A copper thin film can be formed at a deposition rate of about a minute.

When the solution vaporizer 10 as shown in FIG. 6 is used, more solution can be vaporized at the same time, and even if a large amount of the substrate 34 is placed in the reaction tube 32, a film can be formed at the same growth rate. It becomes possible. In a similar device, C using solid complex compounds such as oxide superconductors, high dielectrics, and ferroelectrics
It can also be used as a solution vaporizer for a VD device. For example,
In the case of producing a Y ₁ Ba ₂ Cu ₃ O superconductor, CuDPM ₂ , BaDPM ₂ , and YDPM, which are solid metal complexes dissolved in a THF (tetrahydrofuran) solvent as a raw material, are used.
₃ (where DPM is dipivaloylmethane) and the temperature of the heater of the solution vaporizer is set to 300 ° C, the CV
The metal complex required for D can be introduced into the reaction tube as a gas having the same composition as the supplied concentration. The metal complex is usually a solid, and becomes thermally unstable near the sublimation temperature, so it is difficult to control the composition by this type of CVD. However, when this solution vaporizer is used, the raw material can be handled as a liquid. It is possible to control the flow rate accurately, and it is possible to avoid blockage of the solution vaporizer, which always occurs when such a solution is introduced into a vaporizer maintained at a constant temperature.

In the above-described example, the electric heater 20 is used as the heat source for forming the temperature gradient by using the gas extraction unit 1.
8 attached. However, any type of heater can be used instead of the electric heater 20. Further, the heat source does not necessarily have to be attached to the gas extracting unit 18. For example, the gas extracting unit 18 may be heated by irradiating the gas extracting unit 18 with electromagnetic waves (for example, infrared rays). Alternatively, an electromagnetic wave having a wavelength that is absorbed by the liquid is supplied to the gas extracting section 18.
A desired temperature gradient can also be created by irradiating the liquid surface from the side.

[0022]

As described above, according to the present invention,
A gas having the same composition as this solution can be constantly extracted from a solution containing two components or two or more components, so that a conventionally complicated structure can be simplified and the reliability of the device can be improved. . Further, in the film forming apparatus according to the present invention, a heart film having an excellent uniform component can be formed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram showing a relationship between a position and a temperature in the solution vaporizer of FIG.

FIG. 3 is a diagram showing a relationship between a position and a concentration in the solution vaporizer of FIG.

FIG. 4 is a diagram showing an equilibrium relationship between a solution and a gas.

FIG. 5 is a view showing an embodiment constituted by a branch pipe.

FIG. 6 is a view showing an embodiment of a CVD apparatus including a solution vaporizer of the present invention.

FIG. 7 is a partial detailed view of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Solution supply apparatus 12 ... Tube 14 ... Solution supply part 16 ... Solution evaporation part 18 ... Gas extraction part 20 ... Heater 22 ... Branch pipe 30 ... CVD apparatus

Claims (7)

[Claims] 1. A solution supply unit for supplying a solution, a solution evaporation unit for evaporating the solution supplied by the solution supply unit, and a gas extraction unit for extracting the evaporated gas. The solution evaporating section and the gas take-out section are in a flow path in which a liquid or a gas flows continuously, and have a temperature gradient such that the temperature increases from the solution supply section toward the gas take-out section. Solution vaporizer. 2. The solution vaporization device is constituted by a tube, and a cross-sectional area of the tube is such that a linear flow rate at which liquid flows from the solution supply unit to the solution evaporation unit is equal to the solution supply unit and the solution evaporation unit. 2. The solution vaporizer according to claim 1, wherein the solution vaporization speed is sufficiently faster than the diffusion speed of the solute due to the concentration difference of the solution occurring between the two. 3. The temperature gradient according to claim 2, wherein the gas outlet is heated, and the heat is radiated from the solution supply unit toward the gas outlet to form the temperature gradient. Solution vaporizer. 4. The solution vaporizer according to claim 3, wherein a heater is attached to the gas outlet. 5. The solution vaporizer according to claim 3, wherein the gas outlet is heated by irradiating the gas outlet with electromagnetic waves. 6. The solution vaporizer according to claim 1, comprising a pipe branched from a common solution supply section to a plurality of solution evaporation sections and a gas extraction section. 7. A film forming apparatus comprising the solution vaporizer according to claim 1.