JP2005259723A - Raw material solution discharge device, vaporizer for cvd, solution vaporizing cvd device, flow control method, and thin film forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable the precise control of the amount of a flow of a raw material solution for CVD. <P>SOLUTION: A raw material solution discharge device comprises a raw material solution accommodation chamber for accommodating the raw material solution for CVD; a nozzle hole 11a which is formed in the wall member of the raw material solution accommodation chamber, and through which the raw material solution is discharged; a pressure unit 12a for pressing the raw material solution accommodated in the raw material solution accommodation chamber 11 based on an input signal, and for discharging the raw material solution from the nozzle hole 11a; and a control unit for controlling the transmission of a signal to control the amount of the raw material solution discharged from the nozzle hole 11a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flow rate controller, a CVD vaporizer, a solution vaporization type CVD apparatus, a flow rate control method, and a thin film formation method, and in particular, a flow rate controller capable of accurately controlling the flow rate of a raw material solution for CVD, The present invention relates to a vaporizer for CVD, a solution vaporization type CVD apparatus, a flow rate control method, and a thin film formation method.

  In the CVD (chemical vapor deposition) technology introduced and adopted in the semiconductor industry from around 1970, when forming a thin film material, a reactive material in a gas state is caused to flow into the reactor to cause a chemical reaction, and various kinds of materials are formed on a semiconductor substrate such as silicon. A thin film material having a proper composition is formed. However, there is a limitation of the CVD technique that a thin film cannot be formed by a CVD method unless a gaseous reaction material is prepared.

  At IEDM in 1987, W.I.KINNEY etal announced a technology for creating high-speed nonvolatile memory FeRAM using the polarization phenomenon of ferroelectric materials (PZT, SBT, etc.). At that time, because it was not possible to produce gaseous raw materials containing Zr, Sr, and Bi, thin films such as ferroelectric materials PZT and SBT could not be produced by the CVD method. For this reason, a solution coating method, which is a process similar to that for forming a photoresist thin film, has been adopted for the production thereof. Ferroelectric material thin films (thickness 400-300nm) produced by solution coating method have poor step coverage, and pinholes increase and electrical insulation decreases when the thickness is reduced (thickness 150-40nm). There was a problem. In order to put FeRAM-LSI into practical use, where there are many steps and it is essential to reduce the thickness of the ferroelectric material (thickness: 100-50 nm), it is essential to have a technique for producing high-quality ferroelectric thin films using the CVD method. is there.

  In 1992, Associate Professor Shiozaki of Kyoto University's Faculty of Engineering made the ferroelectric thin film PZT by the CVD method for the first time in the world and presented it to the academic society. At this time, the CVD apparatus employed by Dr. Shiozaki employs a method of sublimating the solid raw material to gasify it (see FIG. 23).

  However, the method of sublimating a solid material to gasify has the following problems. Since the sublimation rate when sublimating the solid raw material is slow, it is difficult to increase the flow rate of the reactant, and it is difficult to control the flow rate of the reactant, so the deposition rate of the thin film is small and the reproducibility is poor. . Moreover, it was difficult to transport the sublimated solid raw material to the reactor using a pipe heated to about 250 ° C.

  The present inventor purchased the equipment adopted by Dr. Shiozaki from the same equipment manufacturer as Dr. Shiozaki and conducted a film formation test with the support of Dr. Shiozaki in order to pursue the presentation technology of Dr. Shiozaki. However, the high-temperature piping was clogged immediately after the start of operation. Immediately after repairing this time, a part of the high-temperature piping part was abnormally overheated. From this experience, heating a thin and long (1/4 inch external shape, length 1 m × several) stainless steel pipe with multiple valves in the middle of the pipe to a high temperature of about 250 ± 5 ° C. Concluded that this is an extremely difficult technology.

The present inventor concluded from the above experience that it is difficult to put a sublimation CVD apparatus into practical use. Therefore, by employing a solution vaporization CVD method (so-called Flash CVD method), the world succeeded in forming a high-quality thin film of ferroelectric material SBT for the first time in the world (see FIG. 24). This international conference ISIF'96 ( "Performance of SrBi2Ta2O9 Thin Films Grown by Chemical Vapor Deposition for Nonvolatile Memory Applications" .C.Isobe, H.Yamoto, H.yagi et al, 9 th Internatinal Symposium on Integrated Ferroelectrics.Mar.1996 ) For the first time in the world to demonstrate the possibility of commercializing high-speed nonvolatile memory FeRAM-LSI.

FIG. 25 shows, in a tabular form, an example of a film that can be formed by a solution vaporization CVD method, raw materials for forming the film, and characteristics thereof. For example, when forming an SBT thin film, the raw materials are Sr (DPM) ₂ , BiPh ₃ , Ta (OEt) ₅ , Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ , Bi (OtAm) ₃ , Bi ( MMP) _{3 and the} like are adopted, but when Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ and Bi (MMP) ₃ shown in FIG. 25 are used, at a low temperature (350 to 420 ° C.). High-speed deposition (20-100 nm / min.) Is possible, and the formed SBT thin film exhibits excellent step coverage and excellent electrical characteristics.

An example of a solution vaporization CVD method using Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ and Bi (MMP) ₃ will be described below.
FIG. 26 shows the change in the composition of the SBT film when the flow rate of Bi (MMP) _{3 /} ECH 0.2 mol / L is changed. As can be seen from the figure, under the conditions shown in the figure, the composition of the film improves when the flow rate of Bi (MMP) _{3 /} ECH 0.2 mol / L is about 0.2 ccm.

FIG. 27 shows a change in the composition of the SBT film when the flow rate of Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] _{2 /} ECH 0.1 mol / L is changed. As can be seen from the figure, under the conditions shown in the figure, the film composition is improved when the follow rate is 0.12 ccm or less.

FIG. 28 shows the pressure dependence of the deposition rate of the SBT film. From this figure, it can be seen that under the conditions shown in the figure, the deposition rate increases as the pressure increases when the pressure is 300 Pa or less, but the deposition rate does not change much when the pressure is 300 Pa or more.
FIG. 29 shows the pressure dependence of the composition of the SBT film. From this figure, it can be seen that the film composition is improved when the pressure is 200 Pa or higher under the conditions shown in the figure.
FIG. 30 shows changes in the deposition rate of the SBT film when the flow rate of the raw material solution is changed. The ratio of the flow rate of the raw material solution Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] _{2 /} ECH 0.1 mol / L and Bi (MMP) _{3 /} ECH 0.2 mol / L is always 25:19. is there. As can be seen from the figure, under the conditions shown in the figure, the deposition rate is within the range where the flow rate of Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] _{2 /} ECH 0.1 mol / L is 0.5 ccm or less. Is substantially proportional to the flow rate of the raw material solution.

FIG. 31 shows the distribution of SrO in the Pt wafer. Since the SrO content of the thin film is within the range of 35 mol% to 37 mol%, it can be seen that SrO is contained almost uniformly over almost the entire surface of the wafer.
FIG. 32 shows the distribution of Bi ₂ O ₃ in the Pt wafer. Since the Bi ₂ O ₃ content of the thin film is within the range of 35 mol% to 37 mol%, it can be seen that Bi ₂ O ₃ is contained almost uniformly over almost the entire surface of the wafer.
FIG. 33 shows the distribution of Ta ₂ O ₅ in the Pt wafer. Since the Ta ₂ O ₅ content of the thin film is within the range of 27 mol% to 28.5 mol%, it can be seen that Ta ₂ O ₅ is contained almost uniformly over almost the entire surface of the wafer.

FIG. 34 is a graph showing the results of examining the reproducibility of the deposition rate of the SBT thin film. The average deposition rate was 7.29 nm / min (σ = 0.148 nm / min). This shows that the reproducibility of the deposition rate is good.
FIG. 35 is a graph showing the susceptor temperature dependence of the SBT thin film deposition rate. As can be seen from this graph, the deposition rate decreases as the susceptor temperature decreases at about 1 / 0.00157K, that is, about 630k or less, but becomes substantially constant at about 1 / 0.00157K or more.

  FIG. 36 is an SEM photograph showing a cross-sectional structure of a substrate on which an SBT thin film is deposited by a solution vaporization CVD method. The substrate is provided with a groove in advance, and the SBT thin film is formed on the groove. As can be seen from this photograph, the SBT thin film formed by the solution vaporization CVD method has excellent step coverage.

  FIG. 37 is a graph showing the polarization characteristics of an SBT thin film formed by a solution vaporization CVD method. From this figure, it can be seen that this SBT thin film has good electrical characteristics.

  By the way, in the solution vaporization type CVD method, it is necessary to prepare a raw material solution by dissolving a solid material in a solvent, and gasify the raw material solution to prepare a reaction gas necessary for the SBT thin film synthesis reaction. As a vaporizer for this purpose, an American ATMI product (shown in FIG. 38) was initially adopted to produce a solution control device (shown in FIG. 39). However, since this vaporizer is clogged in a few dozen hours, it cannot be used as a vaporizer for a mass production CVD apparatus. Therefore, in 1996, the inventor supplied Shimadzu Corporation, Yoshioka, Yamagata University, Faculty of Engineering, Department of Materials Engineering, Professor Tsuda, and provided high-performance solutions necessary for stable deposition of high-quality SBT thin films. We ordered and delivered the development and manufacture of control systems and high-performance vaporizers. However, in the developed and delivered device (solution supply control device and vaporizer: FIGS. 40, 41, 42, 43 (a), (b), (c), (d), and FIG. 44), SBT thin film could not be formed stably. This apparatus is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2000-216150) and Patent Document 2 (Japanese Patent Laid-Open No. 2002-105646).

The present inventor has clarified that the reason why the SBT thin film could not be stably formed by the above-described vaporizer is as follows.
The reactants for synthesizing the SBT thin film are Sr (DPM) ₂ , BiPh ₃ , Ta (Oet) ₅ , Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ , Bi (OtAm) ₃ , Bi (MMP) ₃ or the like is employed, but particularly when Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ + Bi (MMP) ₃ is used, high-speed deposition (5 to 100 nm at a low temperature of 320 to 420 ° C. / min), and it is possible to form a high-quality SBT thin film that exhibits excellent step coverage and excellent electrical characteristics. However, in the above device (solution supply control system and vaporizer), when Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ + Bi (MMP) ₃ is used as the reaction gas, the device is clogged in a short time. Resulting in. The present inventor has found that the cause is that when a solution of Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ + Bi (MMP) ₃ is mixed at room temperature, Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe )] ₂ and Bi (MMP) ₃ reacted to synthesize a substance having low solubility and difficult to sublimate, and found that the flow path for the solution and the tip of the vaporization tube are clogged.

For example, the vaporizer shown in detail in each of FIGS. 43A to 43D has a plurality of channels, and the second stage immediately after mixing the raw material solutions that have passed through these channels. The atomization structure is adopted. For this reason, there should be almost no possibility that a reaction product having a low solubility and difficult to vaporize is produced.
However, in practice, as a method of forming a plurality of flow paths, a rod having the same outer shape as the inner diameter of the cylindrical or conical hollow portion is inserted into the dispersion body having the cylindrical or conical hollow portion. The structure is adopted. One or more grooves are formed on the outer periphery of the rod. Here, since it is impossible in principle to make the gap between the double pipes zero, the flow path is leaked. For this reason, a plurality of flow paths cannot be made independent. For this reason, a substance having low solubility and difficult to sublimate has been synthesized.
Moreover, as shown in FIG. 44, it has the structure which mixes a raw material solution in the middle of piping. For this reason, it is easy to synthesize a substance having lower solubility and difficult to sublimate.
Hereinafter, these will be described in detail. Note that the physical property data of the substances described below is shown in the table of FIG.

FIG. 46 is a diagram showing TG CHART (Ar 760/10 Torr, O ₂ 760 Torr) of Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ . This figure shows the rate of temperature increase of a sample of Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ from 30 ° C. to 600 ° C. at 10 ° C./min in an argon atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. Graph 101 showing the change in the weight of the sample when the temperature is raised at a temperature of 10 ° C., and the temperature of the sample is raised from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an argon atmosphere with a pressure of 10 Torr and a flow rate of 50 ml / min. Graph 102 showing the change in the weight of the sample when the sample is heated, and when the temperature of the sample is raised from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an oxygen atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. The graph 103 which shows the change of sample weight is shown. From this figure, it can be seen that Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ completely sublimes at about 220 ° C. under a pressure of 10 Torr in an argon atmosphere.

FIG. 47 is a diagram showing TG-DTA CHART (O ₂ 760 Torr) of Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ . This figure shows a sample heating rate of 10 ° C./min from 30 ° C. to 600 ° C. for a sample of Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ in an oxygen atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. The graph 104 which shows the change of the sample weight at the time of making it heat up by and the graph 105 which shows a differential thermal analysis result are shown. From this figure, it is understood that Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ has a differential heat peak in the vicinity of 260 ° C. in an oxygen atmosphere.

FIG. 48 is a diagram showing TG CHART (Ar 760/10 Torr, O 2 760 Torr) of Bi (OtAm) ₃ . This figure shows changes in sample weight when a Bi (OtAm) ₃ sample was heated from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an argon atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. And a graph showing changes in the sample weight when the sample was heated from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an argon atmosphere with a pressure of 10 Torr and a flow rate of 50 ml / min. 112 shows a graph 113 showing a change in the weight of the sample when the temperature of the sample is raised from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an oxygen atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. ing. From this figure, it can be seen that Bi (OtAm) ₃ sublimates about 98% at about 130 ° C. under a pressure of 10 Torr in an argon atmosphere.

FIG. 49 is a diagram showing TG-DTA CHART (O ₂ 760 Torr) of Bi (OtAm) ₃ . This figure shows changes in sample weight when a Bi (OtAm) ₃ sample was heated from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an oxygen atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. The graph 114 which shows this, and the graph 115 which shows a differential thermal analysis result are shown. From this figure, it can be seen that Bi (OtAm) ₃ has a differential heat peak in the vicinity of 205 ° C. in an oxygen atmosphere.

FIG. 50 is a diagram showing TG CHART (Ar 760/10 Torr, O 2 760 Torr) of Bi (MMP) ₃ . This figure shows changes in sample weight when a Bi (MMP) ₃ sample was heated from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an argon atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. And a graph showing changes in the sample weight when the sample was heated from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an argon atmosphere with a pressure of 10 Torr and a flow rate of 50 ml / min. 122 shows a graph 123 showing a change in the weight of the sample when the temperature of the sample was raised from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an oxygen atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. ing. From this figure, it can be seen that Bi (MMP) ₃ completely sublimes at about 150 ° C. under a pressure of 10 Torr in an argon atmosphere.

FIG. 51 is a diagram showing TG-DTA CHART (O ₂ 760 Torr) of Bi (MMP) ₃ . This figure shows the change in sample weight when a Bi (MMP) ₃ sample was heated from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an oxygen atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. The graph 124 which shows this and the graph 125 which shows a differential thermal analysis result are shown. From this figure, it can be seen that Bi (MMP) ₃ has a differential heat peak in the vicinity of 209 ° C. in an oxygen atmosphere.

FIG. 52 is a diagram showing TG CHART (Ar 760/10 Torr, O 2 760 Torr) of a Bi (OtAm) ₃ / Sr [Ta (OEt) ₆ ] ₂ mixture. This figure shows that a sample of Bi (OtAm) ₃ / Sr [Ta (OEt) ₆ ] ₂ mixture was heated from 30 ° C. to 600 ° C. at 10 ° C./min in an argon atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. The graph 131 shows the change in the sample weight when the temperature is raised at a rate, and the sample is raised from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an oxygen atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. The graph 133 which shows the change of the sample weight at the time of making it warm is shown. This figure shows that the Bi (OtAm) ₃ / Sr [Ta (OEt) ₆ ] ₂ mixture sublimates only about 80% even when heated to 300 ° C. or higher in an argon atmosphere.

From the above, Sr [Ta (OEt) ₆ ] ₂ and Bi (OtAm) ₃ are sublimated almost 100% by themselves, but when they are mixed, there is a portion that does not sublime. This deteriorated sublimation characteristic is thought to cause clogging of the vaporizer.

The cause of the deterioration of the sublimation characteristics can be understood from the NMR (H nuclear magnetic resonance) characteristics shown in FIG.
When Bi (OtAm) ₃ and Sr [Ta (OEt) ₆ ] ₂ are mixed, a new NMR characteristic is observed, indicating that a new compound is formed and present.

FIG. 54 is a diagram showing TG CHART (Ar 760 Torr) of a Bi (MMP) ₃ / Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ mixture. This figure shows a sample of Bi (MMP) ₃ / Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ mixture from 30 to 600 ° C. in an argon atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. It is a graph which shows the change of the sample weight at the time of heating up with the temperature increase rate of 10 degreeC / min. From this figure, it can be seen that the Bi (MMP) ₃ / Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ mixture also sublimes only about 80% in an argon atmosphere.

FIG. 55 is a diagram showing BiPh ₃ TG CHART (Ar 760/10 Torr, O 2 760 Torr). This figure is a graph 141 showing a change in sample weight when a sample in an argon atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min is heated from 30 ° C. to 600 ° C. at a rate of 10 ° C./min. A graph 142 showing a change in the weight of the sample when the temperature of the sample was increased from 30 ° C. to 600 ° C. at a rate of temperature increase of 10 ° C./min in an argon atmosphere with a pressure of 10 Torr and a flow rate of 50 ml / min. The graph 143 shows the change in sample weight when the sample was heated from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an oxygen atmosphere at 760 Torr and a flow rate of 100 ml / min. From this figure, it can be seen that BiPh ₃ sublimates 100% at about 200 ° C.

FIG. 56 is a diagram showing TG CHART (Ar 760, O ₂ 760 Torr) of a BiPh ₃ / Sr [Ta (OEt) ₆ ] ₂ mixture. This figure shows that a sample of BiPh ₃ / Sr [Ta (OEt) ₆ ] ₂ mixture was raised from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an argon atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. A graph 151 showing a change in the weight of the sample when heated, and the temperature of the sample was increased from 30 ° C. to 600 ° C. at a rate of 10 ° C./min in an oxygen atmosphere with a pressure of 760 Torr and a flow rate of 100 ml / min. The graph 153 which shows the change of the sample weight in a case is shown. From this figure, it can be seen that the BiPh ₃ / Sr [Ta (OEt) ₆ ] ₂ mixture sublimes almost 100% at about 280 ° C.

FIG. 57 is a diagram showing mixing stability of BiPh3 & Sr [Ta (OEt) 6] 2 (NMR) characteristics. From this figure, synthesis of a new substance is not observed in the BiPh ₃ / Sr [Ta (OEt) ₆ ] ₂ mixture.
FIG. 58 is a diagram showing BiPh ₃ TG-DTA CHART (O ₂ 760 Torr). As shown in this figure, the oxidation reaction of BiPh ₃ occurs at 465 ° C. _{This, Sr [Ta (OEt) 5} (OC 2 H 4 OMe)] 2 of 259 ℃, Bi (MMP) ₃ of 209 ° C., in comparison with the Bi (OtAm) ₃ of 205 ° C., since the oxidation temperature is too high , It is difficult to adopt.

As shown in FIG. 45, Bi (OtAm) ₃ undergoes a hydrolysis reaction with only 180 ppm of water. Compared to the fact that Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ is 1650 ppm of water and Bi (MMP) ₃ is 1170 ppm of water, a hydrolysis reaction occurs. It is sensitive and indicates that Bi (OtAm) ₃ is difficult to handle. Since moisture always exists, the moisture and Bi (OtAm) ₃ react to increase the possibility that the produced Bi oxide clogs the piping and the flow meter.

  By the way, in the solution vaporization type CVD method, since most of the solution is an organic solvent, when this is gasified to form a CVD thin film, carbon (for example, 5-8 at% in SBT) is contained in the film. This carbon is an impurity and causes the electrical characteristics of the thin film to deteriorate. For this reason, it is necessary to reduce the amount of the solvent that flows during film formation.

Since the minimum full scale flow rate of a liquid mass flow controller that is widely used is currently 0.05 cc / min., The minimum control flow rate is about 0.005 cc / min., And it is difficult to control a flow rate smaller than this. For this reason, when forming an ultrathin film (1-10 nmT, HfSiOx) or when performing donor / acceptor concentration control (10exp14 to 10exp20 atoms / cc), a general liquid massflow controller has a minimum control flow rate that is too large.
For this reason, in order to reduce the solid raw material flow rate, it is necessary to reduce the concentration of the solid raw material in the solution, which means that the amount of the solvent necessary for supplying the same amount of the solid raw material is increased. . In this case, carbon, that is, impurities in the formed thin film increase.

Further, in the conventional solution vaporization type CVD method, for example, a Bi (MMP) ₃ solution (concentration 0.1 mol / L, solvent is ECH 3) is pressurized with a gas or the like and flows into a narrow tube, and the flow rate in this narrow tube is measured by liquid mass flow. Controlled by the controller. In this method, when the solution is pressurized with gas, the pressurized gas dissolves in the solution in proportion to the pressure, and the pressurized gas dissolved in proportion to the decrease in the pressure of the solution comes out downstream of the liquid mass flow controller and bubbles are generated. Form. The volume of the foam reaches 10% to 50% depending on the gas pressurizing condition and the like, and causes the fluctuation of the solution flow rate.

  Further, when a thin film is formed by a solution vaporization type CVD method using a liquid mass flow controller, the initial flow rate is not stable, so that it is difficult to control the composition of the initial growth layer of the thin film.

  Furthermore, the liquid mass flow controller is not only expensive (about 300,000 yen / unit), but also requires periodic disassembly and cleaning, accuracy inspection and calibration (for example, every 2-3 months), and maintenance costs are enormous. It is.

JP 2000-216150 A (paragraphs 76-78, 145-167, FIG. 3, FIG. 8) JP 2002-105646 A (13th to 14th paragraphs, FIG. 2)

The problems of the prior art described above are summarized as follows.
A technique in which a solid material is sublimated and gasified at room temperature and used as a reaction gas for CVD has a problem that the deposition rate of a thin film is slow and varies, so that practical application is considered difficult. For this reason, it is desired to use a solution vaporization type CVD method, which is a technique in which a raw material that is solid at room temperature is dissolved in a solvent, atomized, and then vaporized at a high temperature. One of the problems of the solution vaporization CVD method is the development of a technique for accurately controlling the flow rate of a raw material solution obtained by dissolving a solid raw material in a solvent.

  The present invention has been made in view of the above circumstances, and its purpose is to provide a raw material solution discharger, a CVD vaporizer, and a solution vaporization type capable of accurately controlling the flow rate of the raw material solution for CVD. A CVD apparatus, a flow rate control method, and a thin film formation method are provided.

In order to solve the above problems, the raw material solution discharger according to the present invention is:
A raw material solution storage chamber for storing a raw material solution for CVD;
A nozzle hole formed in a wall material of the raw material solution storage chamber and from which the raw material solution is discharged;
A pressurizing unit configured to pressurize the raw material solution stored in the raw material solution storage chamber based on an input signal and discharge the raw material solution from the nozzle hole;
And a controller that controls the amount of the raw material solution discharged from the nozzle hole by controlling the transmission of the signal.

  According to this raw material solution discharger, the raw material solution is discharged as droplets from the nozzle holes. The size of the droplet is, for example, 1 picoliter (pL) to several μL, and the number of droplets can be controlled by controlling the number of nozzle holes and the number of input signals. For this reason, the raw material solution can be accurately controlled in the range of, for example, 100 pL / min to 1 cc / min.

Another raw material solution dispenser according to the present invention is:
A raw material solution storage chamber for storing a raw material solution for CVD;
A nozzle hole formed in the raw material solution storage chamber and from which the raw material solution is discharged;
And a pressurizing unit that discharges the raw material solution from the nozzle hole by pressurizing the raw material solution stored in the raw material solution storage chamber.

  According to this raw material solution discharger, the raw material solution is discharged as droplets from the nozzle holes. The size of the droplet is, for example, 1 picoliter (pL) to several μL. For this reason, by controlling the number of droplets, the raw material solution can be accurately controlled in the range of, for example, 100 pL / min to 1 cc / min.

  The pressurizing unit can include a piezoelectric body that pressurizes the raw material solution by expanding and contracting, and includes a solenoid and a pressurizing member that moves by the magnetic force generated by the solenoid and pressurizes the raw material solution. Is also possible.

The raw material solution dispenser according to the present invention is
A raw material solution storage chamber for storing a raw material solution for CVD;
A nozzle hole that is formed in the wall material of the raw material solution storage chamber and from which droplets of the raw material solution are discharged;
A collection unit for collecting the droplets;
A charging electrode that is located between the nozzle hole and the recovery portion and charges the droplet;
A control electrode that is positioned between the charging electrode and the recovery unit and that changes the path of the charged droplets in an external direction by generating an electric field based on a signal;
It is characterized by comprising.

  According to this raw material solution discharger, the raw material solution is discharged as droplets to the outside. The size of the droplet is, for example, 1 picoliter (pL) to several μL. For this reason, by controlling the number of droplets, the raw material solution can be accurately controlled in the range of, for example, 100 pL / min to 1 cc / min.

The vaporizer for CVD according to the present invention is
A raw material solution dispenser according to any of the above,
A dispersion unit for dispersing the raw material solution discharged from the raw material solution discharger in a carrier gas;
A carrier gas passage for supplying the carrier gas to the dispersing portion;
A vaporizing unit that vaporizes the raw material solution dispersed in the dispersing unit;
It is formed in the part which connects the said vaporization part and the said dispersion | distribution part, The said raw material solution disperse | distributed by the said dispersion part comprises the pore introduce | transduced into the said vaporization part.

In this vaporizer for CVD, when the raw material solution is vaporized, the vaporization part is in a reduced pressure state with respect to the dispersion part, and the raw material solution is introduced into the vaporization part based on the pressure difference between the dispersion part and the vaporization part. Thus, the raw material solution can be vaporized. Further, when the vaporizing unit vaporizes the raw material solution, the vaporizing unit is in a reduced pressure state with respect to the dispersing unit, and the raw material solution is heated to a high temperature while being introduced and expanded based on the pressure difference between the dispersing unit and the vaporizing unit. It is also possible to vaporize the raw material solution. It is also possible to heat the dispersion part to a high temperature to vaporize the raw material solution in the dispersion part and introduce the vaporized raw material solution into the vaporization part by a pressure difference between the dispersion part and the vaporization part.
A plurality of raw material solution discharge devices are provided, and each of the plurality of raw material solution discharge units can discharge different raw material solutions to the dispersion unit.

When the raw material solution is a solution in which a solid or liquid raw material is dissolved in a solvent, the dispersion unit may further include a solvent supply unit that supplies a solvent separately from the raw material solution.
In the droplets discharged from the raw material solution discharger, only the solvent may be vaporized in the dispersion portion. On the other hand, when the solution supply unit is provided, the vapor pressure of the solvent in the dispersion unit can be increased, so that only the solvent can be prevented from being vaporized.

  A solution vaporization type CVD apparatus according to the present invention comprises any one of the above-described CVD vaporizers.

Another solution vaporization type CVD apparatus according to the present invention is:
A vaporizer for CVD according to any one of the above,
A reaction chamber connected to the vaporizer of the CVD vaporizer;
Comprising
The film formation is performed using the raw material solution vaporized in the vaporization section.

The flow control method according to the present invention includes:
Comprising the step of flowing the raw material solution by repeatedly pressurizing the raw material solution for CVD stored in the raw material solution storage chamber provided with the nozzle hole, and repeatedly discharging the raw material solution from the nozzle hole,
The flow rate of the raw material solution is controlled by controlling the number of times of discharging the raw material solution.

The thin film forming method according to the present invention includes:
Supply the raw material solution for CVD while controlling the flow rate using the above flow rate control method,
Disperse and vaporize the supplied raw material solution in a carrier gas,
A thin film is formed by performing CVD using the vaporized raw material solution.

  As described above, according to the present invention, the raw material solution can be accurately controlled in the range of, for example, 100 pL / min to 1 cc / min.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)

  FIG. 1 is a cross-sectional view schematically showing a CVD vaporizer according to Embodiment 1 of the present invention together with a reaction chamber (CVD chamber) 4. This vaporizer for CVD mixes the raw material solution discharged as the droplet 50 from the raw material solution discharger 1 with the carrier gas in the dispersion part 2, and injects this mixture into the vaporization tube 5 from the dispersion part 2, thereby It vaporizes the solution. The vaporized raw material solution is supplied to the reaction chamber 4 together with the carrier gas, and is used as a raw material gas for film formation by CVD. The CVD vaporizer includes a control unit (not shown).

  The raw material solution discharger 1 is provided with a substantially cylindrical raw material solution storage chamber 11. The raw material solution storage chamber 11 has a substantially conical portion facing the dispersion portion 3, and a nozzle hole 11 a is formed at the tip thereof. A piezoelectric body 12a that expands and contracts in response to an input signal is disposed in a portion of the raw material solution storage chamber 11 opposite to the nozzle hole 11a. When the piezoelectric body 12a expands, the raw material solution in the raw material solution storage chamber 11 is pressurized, and the raw material solution is ejected as droplets 50 from the nozzle holes 11a toward the dispersion portion 2.

The raw material solution storage chamber 11 is supplied with a raw material solution obtained by mixing a chemical in a solvent (solvent) from a raw material solution pipe 13. The chemical is, for example, a solid raw material dissolved in a solvent, but may be a liquid raw material. The liquid raw material is, for example, Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ , Cu (EDMDD) 2, or the like having a high viscosity and a low vapor pressure. In the case of a liquid raw material, the raw material solution may be composed of a single liquid raw material. The base end side of the raw material solution pipe 13 is connected to a first supply mechanism 14 for supplying chemicals and solvents. The first supply mechanism 14 has a chemical supply source and a solvent supply source. A valve 14 a is provided between the chemical supply source and the raw material solution pipe 13, and a valve 14 b is provided between the solvent supply source and the raw material solution pipe 13. Further, the solvent and the chemical are joined (mixed) between the solvent supply source and the raw material solution pipe 13. A solution reservoir 13 a is formed between the raw material solution storage chamber 11 and the raw material solution pipe 13. The solution reservoir 13a functions as a buffer for the raw material solution. For this reason, even if the piezoelectric body 12a expands and contracts at a high frequency and discharges the droplet 50, each time the droplet 50 is discharged, the raw material solution is quickly replenished to the raw material solution storage chamber 11.

In addition, although the raw material solution discharger 1 shown in the figure is one, plural types of raw material solutions (for example, Bi (MMP) ₃ solution and Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ solution) Is used, the vaporizer for CVD has one or a plurality of raw material solution dischargers 1 for each raw material solution. Also in this case, each of the plurality of raw material solution dischargers 1 discharges the droplets 50 to the dispersion unit 2.

  The dispersion part 2 has a substantially cylindrical hollow part 21 inside. A nozzle hole 11 a of the raw material solution discharger 1 is connected to the proximal end side of the hollow portion 21. The tip of the hollow portion 21 has a substantially conical shape, and an injection hole 21 a connected to the vaporizing tube 3 is formed.

The distal end side of the carrier gas pipe 22 is connected to the inner wall of the hollow portion 21. The base end side of the carrier gas pipe 22 is connected to a second supply mechanism 23 that supplies argon gas and nitrogen gas. The second supply mechanism 23 has a supply source for supplying argon gas (Ar) and a supply source for supplying nitrogen gas (N ₂ ). A valve 23 a and a mass flow controller (not shown) are provided between the argon gas supply source and the carrier gas pipe 22. A valve 23 b and a mass flow controller (not shown) are provided between the nitrogen gas supply source and the carrier gas pipe 22. A high-precision pressure gauge 24 is disposed between the second supply mechanism 23 and the carrier gas pipe 22. The high-precision pressure gauge 24 constantly monitors the pressure of the carrier gas in the carrier gas pipe 22. The high-precision pressure gauge 24 can send an output signal to a control unit (not shown). Thereby, it is possible to display and monitor the pressure of the carrier gas on the control screen.

  One end of the vaporizing tube 3 is connected to the injection hole 21a of the dispersing portion 2 as described above. A heater 32 is provided around the vaporization tube 3, and the vaporization tube 3 is heated to, for example, about 270 ° C. by this heater. A part of the side surface portion on the other end side of the vaporizing tube 3 is connected to the reaction chamber 4 through a shut valve 33 and a pipe 33a. A vaporized raw material solution is supplied to the reaction chamber 4 via the shut valve 33 and the pipe 33a, and film formation by CVD is performed using this raw material solution. The other end of the vaporizing tube 3 is connected to an exhaust pump (not shown) via a shut valve 34.

Next, the operation of the CVD vaporizer will be described. In this example, the vaporizer for CVD includes a raw material solution discharge device 1 for discharging a raw material solution in which Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ and a solvent are mixed, and Bi (MMP) _3. And a raw material solution discharger 1 for discharging a raw material solution in which a solvent is mixed. The temperature of the raw material solution discharger 1 is controlled to 10 to 35 ° C., desirably 20 to 30 ° C.

  First, as a first stage, in each raw material solution discharger 1, a raw material solution is sealed in advance into the raw material solution storage chamber 11 of the raw material solution discharger 1 through a block valve. A carrier gas (eg, an inert gas such as nitrogen or helium) flows in advance from the dispersion unit 2 to the reaction chamber 4 via the vaporization tube 3. The flow rate is, for example, 2 L / min with nitrogen gas, but may be 500 cc to 3000 cc / min. Further, the raw material solution storage chamber 11 and the raw material solution pipe 13 are controlled to 760 Torr, and the pressure inside the dispersion unit 2 is also controlled to 760 Torr. The reason why these are controlled to a higher pressure is to prevent the solvent from preferentially evaporating from the raw material solution. The pressures of the raw material solution storage chamber 11 and the raw material solution pipe 13 can be controlled by controlling the liquid pressure for supplying the raw material solution, for example. The pressure inside the dispersion unit 2 can be controlled by controlling the flow rate of the carrier gas, for example. These pressures may be 500 Torr to 2000 Torr or 1500 ± 50 Torr. By controlling these pressures, variations in the droplets 50 can be suppressed, and evaporation of the solvent from the droplets 50 can be suppressed.

  On the other hand, the pressure inside the vaporizing tube 3 is controlled to be lower than the dispersing unit 2 (for example, 4 Torr, but may be 1 to 50 Torr), and the pressure inside the reaction chamber 4 is a predetermined value (for example, 0.1 to 5 Torr). The pressure inside the vaporizing tube 3 is determined in proportion to the pressure in the reaction chamber 4 (for example, 10 times).

  Next, as a second stage, a pulse signal is input to the piezoelectric bodies 12a of the two raw material solution ejectors 1 using a control unit (not shown), and the piezoelectric bodies 12a are repeatedly expanded and contracted. The piezoelectric body 12a pressurizes the raw material solution in the raw material solution storage chamber 11 each time it is expanded, and discharges it as a droplet 50 from the nozzle hole 11a. The number of droplets 50 is controlled so that the flow rate of the raw material solution becomes a specified value (for example, 0.05 cc / min). The size of the droplet 50 is, for example, 1 picoliter (pL) to several μL, and the maximum number of droplets 50 is, for example, about 2 × 10exp6 / min. The flying speed of the droplet 50 is, for example, 15 to 50 m / sec, and the flying distance is about 50 mm at the maximum.

Here, the number of droplets 50 per unit time can be controlled by the number of nozzle holes and the frequency of the signal input to the piezoelectric body 12a or the time for inputting the signal. Therefore, the amount of the raw material solution discharged to the dispersion unit 2 can be controlled by controlling the signal input to the piezoelectric body 12a. That is, the raw material solution dispenser 1 functions as a flow rate controller that controls the flow rate of the raw material solution with high accuracy, and can control the flow rate of, for example, 0.05 cc / min with high accuracy. For this reason, when forming an ultrathin film or controlling the donor concentration, it is advantageous compared to the case of using a conventional liquid mass flow controller (liquid MFC).
The flow rate range that can be controlled by the raw material solution dispenser 1 is, for example, 100 pL to 1 cc / min.

  The size of the droplet 50 can be changed by changing the diameter of the nozzle hole 11a. For example, when the diameter of the nozzle hole is 60 μm, the size of the droplet 50 can be controlled to around 100 pL.

  The two types of raw material solution droplets 50 discharged from each of the two raw material solution dischargers 1 are dispersed in the carrier gas in the dispersion unit 2. That is, in this embodiment, since two types of raw material solutions are not mixed directly, it can suppress that these generate chemical reaction in a solution state.

Next, the two kinds of raw material solutions dispersed in the carrier gas in the dispersion unit 2 are introduced into the vaporizing tube 3 through the injection holes 21a and heated to 270 ° C. by the heater.
At this time, since there is a large pressure difference between the dispersing portion 2 and the vaporizing tube 3, the carrier gas and the droplet 50 are ejected into the vaporizing tube 3 at a high speed. At this time, the droplet 50 expands in the vaporizing tube 3 based on the pressure difference between the dispersing portion 2 and the vaporizing tube 3. For this reason, the sublimation temperature of the solid raw material in the droplet 50 falls. In addition, the droplet 50 is further miniaturized during ejection. Accordingly, when the droplet 50 (including the solid raw material in the chemical) is introduced into the vaporizing tube 3, it is vaporized / sublimated instantaneously by the heat from the heater and gasified.

  In this way, a raw material gas is formed by vaporizing two kinds of raw material solutions in a carrier gas with a CVD vaporizer. This source gas is sent to the reaction chamber through the vaporization tube 3 to perform the CVD method, and a thin film is formed on the substrate to be processed.

Here, as a comparative example, an example of a method for forming a thin film by a solution vaporization CVD method using a conventional liquid MFC will be described.
First, as a first step, a solution containing a reactant is sealed from a solution tank to a block valve via a liquid MFC (mass flow controller). At this time, the carrier gas (for example, nitrogen 2 L / min.) Is flowing into the spray section-high-temperature vaporization pipe-vent. A small amount of inert gas or the like is flowed into the reaction chamber, and the reaction chamber is filled with clean gas.

  Next, as a second stage, the valve in the block valve is opened, and the solution containing the reactant is flowed together with the carrier gas to the spray section—high temperature vaporization pipe—vent. After 1 to 2 minutes, the solution flow rate control by the liquid MFC is stabilized. A small amount of inert gas or the like is allowed to flow into the reaction chamber to about 0.1 Torr.

  Next, as a third stage, the switching valve at the lower part of the high-temperature vaporization tube is operated to switch the vaporized gas and the carrier gas from the vent side to the reaction chamber to start the thin film deposition. At the same time, the reaction chamber pressure control value is changed to a specified value (eg, 4 Torr), and control of the reaction chamber pressure is started. After about 1-2 minutes, the reaction chamber pressure is controlled to the specified value.

  As described above, when the conventional liquid MFC is used, since it takes 1-2 minutes for the flow rate to stabilize after startup, the chamber pressure is not controlled to a predetermined value for 1-2 minutes immediately after the start of CVD thin film deposition. Therefore, quality control such as composition of the thin film cannot be performed for 1-2 minutes immediately after the start of deposition.

  In contrast, in the use example of the present embodiment described above, the carrier gas flow rate is, for example, 2 L / min. Of nitrogen, and the amount of gas generated by vaporization of the droplet 50 (for example, about 10 cc / min.). ) Is very large (for example, about 200 times). For this reason, even if the droplets 50 are gasified and sent to the reaction chamber 4, since the fluctuation rate of the gas flow rate is small, the fluctuation of the pressure in the reaction chamber 4 is negligibly small.

  For this reason, in the above use example, since the chamber pressure does not fluctuate immediately after the start of the deposition of the CVD thin film, the film quality does not vary even immediately after the start of the deposition. For this reason, even when producing an extremely thin film (for example, 1 to 10 nm), a high-quality thin film can be easily formed.

  In this embodiment, when the raw material solution is vaporized, if the pressure of the carrier gas is always monitored in real time by the high-precision pressure gauge 24, the pressure gradually increases. This is because when the vaporizer for CVD is continuously used, the solute in the raw material solution gradually precipitates in at least one of the nozzle hole 11a and the injection hole 21a, and gradually clogs the pores (spray ports). It is to let you. This phenomenon is as follows.

Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ and Bi (MMP) ₃ and a solvent (for example, ethylcyclohexane ECH) are placed on the upper part of the high-temperature vaporizing tube 3 under a reduced pressure atmosphere (about 5 to 30 Torr). And a carrier gas (for example, argon, nitrogen, etc.) are sprayed and atomized. At this time, a part of the fog adheres to the spraying port and is liquefied. And since the solution adhering to this spraying port evaporates only the solvent (for example, ethylcyclohexane ECH) with a large vapor pressure by the radiant heat from the vaporization pipe | tube 3 of a pressure-reduced atmosphere and a high temperature state, a solute precipitates and a spraying port is opened. Clog.

As the clogging progresses, the pressure of the carrier gas in the carrier gas pipe 22 increases. After the control unit receives an output signal from the high-precision pressure gauge 24 that the carrier gas pressure has exceeded a predetermined pressure (eg, 200 KPa), the valve 14a is closed and Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ solution and Bi (MMP) ₃ solution are stopped, valve 14b is opened, and only the solvent is allowed to flow. Alternatively, the outlet of the high-temperature vaporization pipe is switched from the reactor to the exhaust side (not shown), and only the solvent and the carrier gas are supplied to the raw material solution pipe 13 and the carrier gas pipe 22 for cleaning. At this time, the flow rate of the solvent can be increased to 2 to 10 times or more of the raw material solution flow rate, and the cleaning effect can be enhanced. Thereby, the solvent can be sprayed from the spraying port, and the solute in the raw material solution which has been deposited can be dissolved again by the solvent and removed by washing. In the present embodiment, the solvent used in the cleaning process is supplied from the first supply mechanism 14. However, the present invention is not limited to this, and a separate solvent supply mechanism for the cleaning process is provided. It is also possible to supply a cleaning solvent from the solvent supply mechanism. Further, it is preferable that the substrate to be processed in the reaction chamber is taken out before cleaning and removed, and a new substrate to be processed is put into the reaction chamber after the cleaning and removal is completed. When the solute in the raw material solution is deposited and adheres to the dispersion 2 and others, a decrease in the deposition rate of the CVD thin film and a change in the composition are observed, which leads to a decrease in the reproducibility of the CVD thin film deposition process and a decrease in quality and yield. means. In order to avoid this, in the actual manufacturing process, it is desirable to perform cleaning before vaporizer clogging is observed. For example, the number of wafers to be manufactured is one, the next wafer is placed in the chamber, and CVD thin film deposition is started. The reproducibility can be improved by cleaning the vaporizing tube during the waiting time of minutes.

  Even during the cleaning process, the pressure of the carrier gas in the carrier gas pipe 22 is monitored by the high-precision pressure gauge 24. This monitors the clogging of the pores. As the washing process is continued, the precipitated solute is dissolved, and the clogging of the pores (spray ports) is gradually eliminated. For this reason, the pressure of the carrier gas decreases. After the control unit receives an output signal from the high-precision pressure gauge 24 that the carrier gas pressure has become a predetermined pressure (for example, 100 Kpa) or less, the valve 14a is opened again to start supplying the solution. Vaporize.

  The pipe capacity from the valves 14a and 14b to the tip of the raw material solution pipe 13 is preferably 8Xcc or less, more preferably 2Xcc or less, and more preferably, when the flow rate of the solution flowing during CVD is Xcc / min. Xcc or less.

  In the first embodiment, the timing for cleaning and removing clogging generated at the spraying port with the solvent is measured by monitoring the pressure of the carrier gas with the high-precision pressure gauge 24. However, the present invention is not limited to this. Instead, it may be removed by washing with a solvent and a carrier gas after a predetermined time has passed.

As described above, according to the first embodiment, when a signal is input to the piezoelectric body 12 a in the raw material solution ejector 1, the piezoelectric body 12 a expands and contracts every time a pulse is input, and the inside of the raw material solution storage chamber 11. The raw material solution is pressurized and discharged to the dispersion section 2 as droplets 50 (1 pL to several μL) from the nozzle holes 11a. For this reason, the raw material solution can be accurately controlled even at a minute flow rate (for example, 0.1 cc / min).
Therefore, since the raw material flow rate per unit time can be controlled in a minute range without reducing the raw material concentration in the solvent, carbon, that is, impurities caused by the solvent does not increase in the formed thin film.

  The raw material solution discharger 1 can be formed by applying an inkjet mechanism of an inkjet printer that is mass-produced. Therefore, the high-quality raw material solution discharger 1 can be formed at low cost.

  Further, since the pressurized gas is not dissolved in the raw material solution, the pressurized gas does not come out on the downstream side to form bubbles. Therefore, there is little fluctuation in the flow rate.

  In this embodiment, two kinds of raw material solutions are discharged as droplets 50 from different raw material solution dischargers 1. In other words, the two raw material solutions are not mixed in the solution state, but are mixed by dispersing the two kinds of raw material solution droplets 50 in the carrier gas in the dispersion section 2, so that the raw material solutions react chemically. Can be suppressed. Therefore, it is possible to suppress synthesis of a substance having low solubility and difficult to sublimate, and it is possible to suppress clogging of the injection holes 21a of the dispersion portion 2. Therefore, the continuous use time of the vaporizer for CVD can be lengthened.

  Further, as described above, in the present embodiment, even if the nozzle hole 11a, the dispersion portion 2, the injection hole 21a and the vaporization tube 3 are clogged, the vaporizer for CVD is obtained by performing the cleaning process and returning to the original state. Can be used stably for a long time. Therefore, a thin film such as the ferroelectric materials PZT and SBT can be formed with good reproducibility and controllability, and high performance of the vaporizer for CVD and the solution vaporization type CVD apparatus can be realized.

  In addition, the spray port can be returned to the original state again by washing the spray port with the solvent before the injection hole 21a is completely clogged. Therefore, by using a cleaning step while using the CVD vaporizer, it is possible to use the CVD vaporizer for a very long time. It takes about 10 hours to disassemble and clean the clogged vaporizer for CVD, and then reassemble it. However, the cleaning process is completed in a few minutes. It becomes possible to reduce it.

  Even if the high-precision pressure gauge 24 is installed as a monitor for monitoring clogging as described above, the CVD vaporizer cannot be used completely continuously because the cleaning process needs to be performed. Therefore, if a plurality of CVD vaporizers with a cleaning mechanism are installed in one reaction chamber, a solution vaporization type CVD apparatus capable of continuous deposition for several hundred hours or more can be realized. Specifically, for example, 12 CVD vaporizers with a cleaning mechanism are installed, 2 of them are always in a cleaning state, and the other 10 CVD vaporizers are always used continuously. By doing so, not only can the solution vaporization type CVD apparatus be operated continuously for several hundred hours or more, but it can be expected that the deposition rate of the thin film will be greatly improved. A solution vaporization type CVD apparatus that performs continuous deposition for a long time while sequentially cleaning a plurality of such vaporizers for CVD is, for example, a superconducting oxide thin film YBCO of about 10 μm on a very long tape-like substrate. This is particularly effective when a film is formed with a thickness.

Further, a solvent supply mechanism that can independently supply the solvent to the hollow portion 21 of the dispersion portion 2 may be provided.
There is a possibility that only the solvent evaporates from the droplet 50 immediately after the droplet 50 of the raw material solution is discharged from the raw material solution discharger 1 to the hollow portion 21. In this case, a solid raw material in the chemical precipitates. When the solid raw material is deposited as a powder, it often adheres to the wall, and the amount of the solid raw material supplied to the reaction chamber 4 decreases. When the solid raw material is deposited as relatively large solid particles, the precipitated solid raw material is introduced into the reaction chamber 4 without being vaporized and adheres as a foreign matter on the thin film.

  The amount of solvent evaporated here is determined by the flow rate, pressure, temperature, and saturated vapor pressure of the solvent. For example, if the carrier gas flow rate, pressure and temperature are 1500 cc / min, 1500 Torr, 20 ° C, and toluene (molecular weight 92.1, specific gravity 0.9 is assumed, saturated vapor pressure 22 Torr (20 ° C)), the amount of solvent evaporation Is 0.1 cc / min in terms of liquid (22 cc / min in terms of gas). When N-hexane (saturated vapor pressure 120 Torr (20 ° C)) is used as the solvent, the amount of evaporation of the solvent is about 1 cc / min in terms of liquid unit.

  On the other hand, if a solvent supply mechanism is provided to supply the solvent to the hollow portion 21, the vapor pressure of the solvent in the hollow portion 21 can be increased, so that the solvent in the droplet 50 is difficult to evaporate. it can. The supply amount of the solvent is, for example, not less than the amount of the solvent assumed to evaporate. In addition, the raw material solution discharge device 1 which discharges only a solvent can be employ | adopted for a solvent supply mechanism, for example.

(Embodiment 2)
FIG. 2 is a cross-sectional view schematically showing the CVD vaporizer according to the second embodiment together with the reaction chamber 4. In the present embodiment, the heater 25 and the heat insulating material 26 are added to the CVD vaporizer according to the first embodiment, and thus the description of the same configuration as that of the first embodiment is omitted.

The heater 25 is located on the outer periphery of the dispersion part 2 and heats the dispersion part 2, that is, the inner wall 21 b of the hollow part 21 to, for example, 270 ° C. The heat insulating material 26 is located between the raw material solution discharger 1 and the dispersion part 2 so that the heat of the dispersion part 2 is not transmitted to the raw material solution discharger 1.
According to this embodiment, the same effect as in the first embodiment can be obtained. Further, since the inner wall 21b of the hollow portion 21 is heated, the droplet 50 (including the solid raw material) is vaporized while falling in the dispersion portion 2 or attached to the inner wall 21b and is vaporized to vaporize with the dispersion portion 2. Based on the pressure difference between the parts 3, the gas is introduced into the vaporization part 3 and then supplied to the reaction chamber 4.

(Embodiment 3)
FIG. 3 is a cross-sectional view schematically showing the CVD vaporizer according to the third embodiment together with the reaction chamber 4. The CVD vaporizer according to the present embodiment is the same as that of the first embodiment except that the raw material solution discharger 1 includes a solenoid 12b and a pressurizing member 12c instead of the piezoelectric body 12a. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In this embodiment, the raw material solution storage chamber 11 of the raw material solution discharger 1 is a substantially rectangular parallelepiped, and a pressurizing member 12c appears and disappears in the raw material solution storage chamber 11 at a portion opposite to the nozzle hole 11a. Arranged to be able to. The pressure member 12c is moved from the case 12 toward the inside of the raw material solution storage chamber 11 by the magnetic force generated by the solenoid 12b, thereby pressurizing the raw material solution in the raw material solution storage chamber 11 and dispersing the raw material solution from the nozzle hole 11a. The liquid droplets 50 are discharged toward the portion 2.

  When the CVD vaporizer according to this embodiment is operated, a control unit (not shown) inputs a pulse signal to the solenoid 12b of the raw material solution discharger 1 to repeatedly generate a magnetic force. Each time the magnetic force is generated, the pressurizing member 12 c reciprocates inside the raw material solution storage chamber 11, pressurizes the raw material solution in the raw material solution storage chamber 11, and discharges it as a droplet 50 from the nozzle hole 11 a. The size of the droplet 50 is, for example, 1 pL to several μL.

Here, the number of droplets 50 per unit time can be controlled by the frequency of a signal input to the solenoid 12b. Therefore, the amount of the raw material solution discharged to the dispersing unit 2 can be controlled by controlling the frequency of the signal input to the solenoid 12b. That is, the raw material solution dispenser 1 functions as a flow rate controller that controls the flow rate of the raw material solution with high accuracy, and can control the flow rate of, for example, 0.05 cc / min with high accuracy.
As in the first embodiment, the size of the droplet 50 can be changed by changing the diameter of the nozzle hole 11a.
Also in this embodiment, the same effect as in the first embodiment can be obtained.

(Embodiment 4)
FIG. 4 is a sectional view schematically showing the CVD vaporizer according to the fourth embodiment together with the reaction chamber 4. In the present embodiment, the heater 25 and the heat insulating material 26 are added to the CVD vaporizer according to the third embodiment, and therefore, the description of the same configuration as that of the third embodiment is omitted.

(I think that there may be droplets that cannot be vaporized in the dispersion part 2. I added a final sentence assuming that case)
The heater 25 is located on the outer periphery of the dispersion part 2 and heats the dispersion part 2, that is, the inner wall 21 b of the hollow part 21 to, for example, 270 ° C. The heat insulating material 26 is located between the raw material solution discharger 1 and the dispersion part 2 so that the heat of the dispersion part 2 is not transmitted to the raw material solution discharger 1.
According to this embodiment, the same effect as in the third embodiment can be obtained. Further, since the inner wall 21b of the hollow portion 21 is heated, the droplet 50 (including the solid raw material) is vaporized while falling in the dispersion portion 2 or attached to the inner wall 21b and is vaporized to vaporize with the dispersion portion 2. Based on the pressure difference between the parts 3, the gas is introduced into the vaporization part 3 and then supplied to the reaction chamber 4. The droplets 50 that have not been vaporized in the dispersion unit 2 are vaporized when introduced from the dispersion unit 2 to the vaporization unit 3 by the same action as in the first embodiment.

(Embodiment 5)
FIG. 5 is a diagram schematically showing a configuration of a CVD vaporizer according to the fifth embodiment. This embodiment is different from the first embodiment in the configuration of the raw material solution discharger. Hereinafter, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. Although not shown in FIG. 5, the CVD vaporizer is connected to a reaction chamber in which CVD is performed.

  In the raw material solution discharger 60 according to this embodiment, the solution discharge mechanism 64 always discharges the droplets 50 of the raw material solution. The configuration of the solution discharge mechanism 64 is substantially equal to the configuration of the raw material solution discharger 1 according to the first or second embodiment, for example. The raw material solution discharger 1 is supplied with a raw material solution from a raw material solution pipe 13. The base end side of the raw material solution pipe 13 is connected to the valve mechanism 63. Chemical and solvent are supplied to the valve mechanism 63 from the chemical supply source 61 and the solvent supply source 62 via pipes 62a and 63a, respectively, and the chemical and solvent are mixed in the valve mechanism 63. Excess chemical or the like returns from the valve mechanism 63 to the chemical supply source 61 via the pipe 63b.

  The raw material solution droplet 50 discharged from the solution discharge mechanism 64 is charged by the charging electrode 65 and then passes between the control electrodes 66 connected to the signal generation circuit 66a. Since the signal voltage is input to the control electrode 66 from the signal generation circuit, the path of the charged droplet 50 changes depending on the electric field between the control electrodes 66 when passing between the control electrodes 66. That is, when it is desired to introduce the droplet 50 into the dispersion unit 2, for example, a signal voltage is input to the control electrode 66 to generate an electric field, and the path of the droplet 50 is changed in the direction of the dispersion unit 2. When it is not desired to drop the droplet 50 into the dispersing unit 2, no signal is sent to the control electrode 66. In this case, the droplet 50 is collected by the gutter 67 and returned to the valve mechanism 63 via the pipe 67a.

  As described above, according to the present embodiment, the number of droplets 50 to be introduced into the dispersion unit 2, that is, the flow rate of the raw material solution can be controlled by controlling the signal generated by the signal generation circuit 66a. Therefore, the same effect as in the first embodiment can be obtained in this embodiment.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in Embodiment 1, the heater may be attached to a part of the inner wall of the raw material solution storage chamber 11 without providing the piezoelectric body 12a. Similarly, in Embodiment 2, a heater may be attached to a part of the inner wall of the raw material solution storage chamber 11 instead of the solenoid 12b and the pressure member 12c. In these cases, the heater is intermittently heated by the input signal, and the raw material solution near the heater is vaporized to generate fine bubbles. The bubbles pressurize the raw material solution in the raw material solution storage chamber 11, and the droplets 50 are discharged from the nozzle holes 11a. In addition, it is preferable to attach a heater to the part facing the nozzle hole 11a.

Further, the CVD vaporizer, CVD vaporization method and solution vaporization type CVD apparatus of the present invention have a wide range of applications, and high-quality ferroelectric thin films (eg, SBT, PZT thin films) for FeRAM-LSI which is a high-speed nonvolatile memory. Not limited to film formation, various solid materials or liquid materials with low vapor pressure are used, YBCO (Super Conductive Oxide), Thick PZT / PLZT / SBT (Filter, MEMS, Optical Interconnect, HD), Metal (Ir, Pt, Cu), Barrier Metal (TiN, TaN), High k (HfOx, Al ₂ O ₃ , BST etc) can be formed.

In the above embodiment, the first raw material solution in which Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ is dissolved in the solvent and the _second raw material solution in which Bi (MMP) ₃ is dissolved in the solvent. Is used as an example, but is not limited to these raw material solutions. YBCO (Super Conductive Oxide) is prepared using a raw material solution prepared by dissolving other solid materials (substances with low vapor pressure) in a solvent. ), Thick PZT / PLZT / SBT (Filter, MEMS, Optical Interconnect, HD), Metal (Ir, Pt, Cu), Barrier Metal (TiN, TaN), High k (HfOx, Al2O3, BST etc) For this purpose, various thin film materials can be formed and supplied. An example is shown in the table of FIG.

  In the above embodiment, the case where one type of thin film is formed on the substrate to be processed has been described. However, the present invention is not limited to this, and a plurality of types of thin films are continuously formed on the substrate to be processed. It is also possible to film. Specifically, the raw material solution and the carrier gas are allowed to flow through the CVD vaporizer to the reaction chamber for an appropriate time to form the first thin film on the substrate to be processed, and then the raw material solution valve is turned to the exhaust side. A new raw material solution is supplied to the reaction chamber via the CVD vaporizer at a predetermined flow rate, and the pipe from the sum of the new raw material flow rate (volume) to the CVD vaporizer is supplied from the valve. When the capacity exceeds 1 to 5 times, a new raw material solution and a carrier gas are passed through the CVD vaporizer for a suitable time to form a second thin film on the substrate to be processed. Thus, it is possible to continuously form two types of thin films having different compositions. Further, by repeating this operation, three or more types of thin films can be continuously formed. Further, when a new raw material solution is supplied to the reaction chamber, the temperature of the substrate to be processed and the reaction pressure in the reaction chamber may be changed.

  In addition, the vaporizer for CVD shown in the first to third embodiments can be used by connecting to the solution supply system shown in FIG. 7, for example.

(Example 1)
Hereinafter, an example of clogging cleaning will be described by using the results of monitoring the pressure of the carrier gas shown in FIGS.
As shown in FIG. 8, when the chemical starts to flow through the vaporizing tube 3 at the monitor point 80, the carrier gas pressure gradually increases. At the point 420, the BiMMP carrier gas pressure is 220 kPa (about 2.2 atm). (Gauge pressure). At this point, BiMMP (0.2 ccm) is stopped and the cleaning solvent ECH is flowed (0.5 ccm). Then, the pressure of the carrier gas rapidly decreases and reaches 120 kPa at 440 points and stabilizes. This decrease in the pressure of the carrier gas indicates that BiMMP adhering to the tip (pores) of the sprayer has been washed away.

9, 10, 11, and 12 are the same, and it can be seen that the phenomenon of adhesion to the tip of the sprayer occurs with good reproducibility. This phenomenon is not limited to SBTCVD using Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ and Bi (MMP) ₃ , but was also observed in PZTCVD using the following chemicals. Chemicals for PZTCVD are Pb (DPM) ₂ / ECH (0.15 mol / L), Zr (DIBM) ₄ / ECH (0.15 mol / L), Ti (Oi-Pr) ₂ (DPM) ₂ / ECH (0.30 mol / L) L).

In FIG. 13, the fluctuation of the carrier gas is small. Since the concentration of the solution of Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ and Bi (MMP) ₃ has been reduced by half, the progress of clogging at the tip of the sprayer (pores) has decreased. I understand that. In FIG. 13, no increase in the pressure of the carrier gas was observed during the deposition of the SBT thin film for about 40 minutes. Further, by performing the cleaning operation every time, SBTCVD can be performed without any clogging. It was.

The results of the SBTCVD reproducibility test with this vaporizer are shown in FIGS.
FIG. 14 shows the reproducibility of the deposition rate. 100 batch deposition rate tests were conducted. The average deposition rate was 7.29 nm / min. Σ = 0.148 nm / min. Excellent continuous deposition and excellent reproducibility were obtained.

  FIG. 15 shows the reproducibility of the film forming composition. A 100-batch deposition rate test was performed, and an excellent reproducibility was obtained with an average Bi / Sr composition ratio of 3.08 σ = 0.065. The Ta / Sr composition ratio averaged 2.07 σ = 0.0166, indicating continuous film formation and excellent reproducibility.

(Example 2)
16 to 22 are data showing the characteristics of the PZT thin film formed using the above-described CVD vaporizer. In this example, the Pb, Zr, and Ti raw material solutions include Pb (DPM) 2 / ECH (0.15 mol / L), Zr (DIBM) 4 / ECH (0.15 mol / L), and Ti (Oi-Pr), respectively. ) 2 (DPM) 2 / ECH (0.30mol / L) is used.

  FIG. 16 shows a change in the deposition rate of the PZT thin film when the pressure in the reaction chamber is changed. In the range below 1400 Pa, the deposition rate of PZT thin film increases with increasing pressure, but the rate of increase decreases with increasing pressure.

  FIG. 17 shows the change in the composition of the PZT thin film when the pressure in the reaction chamber is changed. In the range of 1400 Pa or less, the ratio of Pb to the sum of Zr and Ti gradually decreases as the pressure increases. Further, the ratio of Zr to the sum of Zr and Ti increases linearly as the pressure increases in the range of 800 Pa or less, but the increase rate decreases at higher pressures.

  FIG. 18 shows the change in the deposition rate of the PZT thin film when the temperature of the susceptor is changed. In the range of 600 ° C. to 670 ° C., the deposition rate is substantially constant at about 14 nm / min regardless of the susceptor temperature.

  FIG. 19 shows a change in the composition of the PZT thin film when the temperature of the susceptor is changed. As the temperature of the susceptor increases, the ratio of Pb to the sum of Zr and Ti increases, and the ratio of Zr to the sum of Zr and Ti decreases.

  FIG. 20 shows the change in the composition of the PZT thin film when the flow rate of the Pb raw material solution is changed. The ratio of Pb to the sum of Zr and Ti is almost proportional to the flow rate of the Pb raw material solution. The ratio of Zr to the sum of Zr and Ti is almost constant without being affected by the change in the flow rate of the Pb raw material solution.

  FIG. 21 shows the change in the composition of the PZT thin film when the flow rate of the Zr raw material solution is changed. The ratio of Zr to the sum of Zr and Ti is almost proportional to the flow rate of the Zr raw material solution. The ratio of Pb to the sum of Zr and Ti decreases as the flow rate of the Zr raw material solution increases.

  FIG. 22 is a graph showing the polarization characteristics of a PZT thin film formed by a solution vaporization CVD method. From this figure, it can be seen that this PZT thin film has good electrical characteristics.

  As described above, when the solution vaporization CVD method was used, a PZT thin film could be formed with excellent controllability as well. The reproducibility is also excellent.

2 is a cross-sectional view schematically showing a vaporizer for CVD according to Embodiment 1 together with a reaction chamber 4. FIG. 4 is a cross-sectional view schematically showing a CVD vaporizer according to Embodiment 2 together with a reaction chamber 4. FIG. 6 is a cross-sectional view schematically showing a CVD vaporizer according to Embodiment 3 together with a reaction chamber 4. FIG. 6 is a cross-sectional view schematically showing a CVD vaporizer according to Embodiment 4 together with a reaction chamber 4. FIG. It is a figure which shows typically the structure of the vaporizer for CVD by 5th Embodiment. It is a table | surface which matches and shows the kind of thin film, and the raw material solution used when forming the thin film. It is a figure which shows an example of the solution supply system incorporating the vaporizer for CVD. It is a figure which shows the experimental result which monitored the pressure of carrier gas. It is a figure which shows the experimental result which monitored the pressure of carrier gas. It is a figure which shows the experimental result which monitored the pressure of carrier gas. It is a figure which shows the experimental result which monitored the pressure of carrier gas. It is a figure which shows the experimental result which monitored the pressure of carrier gas. It is a figure which shows the experimental result which monitored the pressure of carrier gas. It is a figure which shows the experimental result which performed the reproducibility test of SBTCVD with the vaporizer for CVD by Embodiment 1. FIG. It is a figure which shows the experimental result which performed the reproducibility test of SBTCVD with the vaporizer for CVD by Embodiment 1. FIG. It is a figure which shows the change of the deposition rate of a PZT thin film when the pressure in a reaction chamber is changed. It is a figure which shows the change of a composition of the PZT thin film when the pressure in a reaction chamber is changed. It is a figure which shows the change of the deposition rate of the PZT thin film when the temperature of a susceptor is changed. It is a figure which shows the change of the composition of a PZT thin film when the temperature of a susceptor is changed. It is a figure which shows the change of the composition of a PZT thin film when the flow rate of Pb raw material solution is changed. It is a figure which shows the change of the composition of a PZT thin film when the flow rate of Zr raw material solution is changed. It is a graph which shows the polarization characteristic of the PZT thin film formed by the solution vaporization type CVD method. It is a figure which shows an example of the conventional CVD apparatus for producing a ferroelectric thin film. It is a figure which shows an example of a solution vaporization type CVD method. It is a table | surface which shows an example of the film | membrane which can be formed into a film by a solution vaporization type CVD method, the raw material for forming the film | membrane, and its characteristic. FIG. 6 is a diagram showing a change in the composition of the SBT film when the flow rate of Bi (MMP) _{3 /} ECH 0.2 mol / L is changed. FIG. 6 is a diagram showing a change in the composition of the SBT film when the flow rate of Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] _{2 /} ECH 0.1 mol / L is changed. It is a figure which shows the pressure dependence of the deposition rate of a SBT film. It is a figure which shows the pressure dependence of the composition of an SBT film. It is a figure which shows the change of the deposition rate of an SBT film when changing the flow rate of a raw material solution. It is a figure which shows distribution of SrO in a Pt wafer. Pt is a diagram illustrating a distribution of Bi ₂ O ₃ in the wafer. Pt is a diagram showing the distribution of of Ta ₂ O ₅ which has a within wafer. It is a graph which shows the result of having investigated the reproducibility of the deposition rate of an SBT thin film. It is a graph which shows the susceptor temperature dependence of the deposition rate of a SBT thin film. It is a SEM photograph which shows the cross-section of the board | substrate which deposited the SBT thin film by the solution vaporization type CVD method. It is a graph which shows the polarization characteristic of the SBT thin film formed by the solution vaporization type CVD method. It is a figure which shows the structure of the vaporizer used by the conventional solution vaporization type CVD method. It is a figure which shows the structure of the solution control apparatus used with the conventional solution vaporization type CVD method. It is a figure which shows the structure of the other vaporizer used by the conventional solution vaporization type CVD method. It is a figure which shows the structure of the other solution control apparatus used with the conventional solution vaporization type CVD method. It is a figure which shows the structure of the other vaporizer used by the conventional solution vaporization type CVD method. (a) is the longitudinal cross-sectional view of the other vaporizer used by the conventional solution vaporization type CVD method, (b) is xx sectional drawing of (a), (c) is y of (a). It is -y sectional drawing, (d) is a longitudinal cross-sectional view of the other vaporizer | carburetor used with the conventional solution vaporization type CVD method. It is a figure which shows the structure of the other solution control apparatus used with the conventional solution vaporization type CVD method. It is a table | surface which shows the physical-property data of the substance relevant to a solution vaporization type CVD method. FIG. 3 is a diagram showing TG CHART (Ar 760/10 Torr, O ₂ 760 Torr) of Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ . FIG. 3 is a diagram showing TG-DTA CHART (O ₂ 760 Torr) of Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ . It is a figure which shows TG CHART (Ar 760 / 10Torr, O2 760Torr) of Bi (OtAm) ₃ . It is a figure which shows TG-DTA CHART (Ar 760 / 10Torr, O2 760Torr) of Bi (OtAm) ₃ . It is a figure which shows TG CHART (Ar 760 / 10Torr, O2 760Torr) of Bi (MMP) ₃ . It is a figure which shows TG-DTA CHART (Ar 760 / 10Torr, O2 760Torr) of Bi (MMP) ₃ . FIG. 3 is a diagram showing TG CHART (Ar 760/10 Torr, O 2 760 Torr) of a Bi (OtAm) ₃ / Sr [Ta (OEt) ₆ ] ₂ mixture. It is a figure which shows a NMR (H nuclear magnetic resonance) characteristic. It is a figure which shows TG CHART (Ar 760Torr) of Bi (MMP) ₃ / Sr [Ta (OEt) ₅ (OC ₂ H ₄ OMe)] ₂ mixture. It is a figure which shows TG CHART (Ar 760 / 10Torr, O2 760Torr) of BiPh ₃ . FIG. ₂ is a diagram showing TG CHART (Ar 760, O ₂ 760 Torr) of a BiPh ₃ / Sr [Ta (OEt) ₆ ] ₂ mixture. It is a figure which shows the Mixing Stability of BiPh3 & Sr [Ta (OEt) 6] 2 (NMR) characteristic. BiPh is a diagram showing a _{3 TG-DTA CHART (O 2} 760Torr).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Raw material solution discharge device 2 ... Dispersing part 3 ... Vaporization tube 4 ... Reaction chamber 11 ... Raw material solution storage chamber 11a ... Nozzle hole 12 ... Case 12a ... Piezoelectric body 12b ... Solenoid 12c ... Pressurizing member 13 ... Raw material solution piping 13a ... Solution reservoir 14 ... 1st supply mechanism 14a, 14b ... Valve 21 ... Hollow part 21a ... Injection hole 21b ... Inner wall 22 ... Pipe for carrier gas 23 ... 2nd supply mechanism 23a, 23b ... Valve 24 ... High precision pressure gauge 25 ... heater 26 ... heat insulating material 32 ... heater 33, 34 ... shut valve 33a ... pipe 50 ... droplet 60 ... raw material solution discharger 61 ... chemical supply source 62 ... solvent supply source 62a, 63a ... pipe 63 ... valve mechanism 64 ... Solution discharge mechanism 65 ... Charging electrode 66 ... Control electrode 66a ... Signal generation circuit 67 ... Gutter 67a ... Piping

Claims (14)

A raw material solution storage chamber for storing a raw material solution for CVD;
A nozzle hole formed in a wall material of the raw material solution storage chamber and from which the raw material solution is discharged;
A pressurizing unit configured to pressurize the raw material solution stored in the raw material solution storage chamber based on an input signal and discharge the raw material solution from the nozzle hole;
A raw material solution discharger comprising: a control unit that controls the amount of the raw material solution discharged from the nozzle hole by controlling the transmission of the signal. A raw material solution storage chamber for storing a raw material solution for CVD;
A nozzle hole formed in the raw material solution storage chamber and from which the raw material solution is discharged;
A raw material solution discharger comprising: a pressurizing unit that discharges the raw material solution from the nozzle hole by pressurizing the raw material solution stored in the raw material solution storage chamber.   The raw material solution ejector according to claim 1, wherein the pressurizing unit includes a piezoelectric body that pressurizes the raw material solution by expanding and contracting. The pressurizing part is
A solenoid,
The raw material solution discharger according to claim 1, further comprising a pressurizing member that moves by the magnetic force generated by the solenoid and pressurizes the raw material solution. A raw material solution storage chamber for storing a raw material solution for CVD;
A nozzle hole that is formed in the wall material of the raw material solution storage chamber and from which droplets of the raw material solution are discharged;
A collection unit for collecting the droplets;
A charging electrode that is located between the nozzle hole and the recovery portion and charges the droplet;
A control electrode that is positioned between the charging electrode and the recovery unit and that changes the path of the charged droplets in an external direction by generating an electric field based on a signal;
A raw material solution discharger comprising: The raw material solution discharger according to any one of claims 1 to 5,
A dispersion unit for dispersing the raw material solution discharged from the raw material solution discharger in a carrier gas;
A carrier gas passage for supplying the carrier gas to the dispersing portion;
A vaporizing unit that vaporizes the raw material solution dispersed in the dispersing unit;
A CVD vaporizer, comprising: pores formed in a portion connecting the vaporizing portion and the dispersing portion, and having the raw material solution dispersed in the dispersing portion introduced into the vaporizing portion.   When the raw material solution is vaporized, the vaporizing unit is in a reduced pressure state with respect to the dispersing unit, and the raw material solution is introduced into the vaporizing unit based on a pressure difference between the dispersing unit and the vaporizing unit. The vaporizer for CVD according to claim 6, wherein the raw material solution is vaporized.   The raw material solution is vaporized in the dispersion part by heating the dispersion part to a high temperature, and the vaporized raw material solution is introduced into the vaporization part based on a pressure difference between the dispersion part and the vaporization part. The CVD vaporizer according to claim 6. Comprising a plurality of the raw material solution discharger,
9. The CVD vaporizer according to claim 6, wherein each of the plurality of raw material solution discharge portions discharges different raw material solutions to the dispersion portion. The raw material solution is a solution in which a solid or liquid raw material is dissolved in a solvent,
The vaporizer for CVD according to any one of claims 6 to 9, further comprising a solvent supply unit that supplies the solvent to the dispersion unit separately from the raw material solution. A solution vaporization type CVD apparatus comprising the vaporizer for CVD according to any one of claims 6 to 10. A vaporizer for CVD according to any one of claims 6 to 10,
A reaction chamber connected to the vaporizer of the CVD vaporizer;
Comprising
A solution vaporization type CVD apparatus which forms a film using the raw material solution vaporized in the vaporization section. Comprising the step of flowing the raw material solution by repeatedly pressurizing the raw material solution for CVD stored in the raw material solution storage chamber provided with the nozzle hole, and repeatedly discharging the raw material solution from the nozzle hole,
A flow rate control method, wherein the flow rate of the raw material solution is controlled by controlling the number of times of discharging the raw material solution. A raw material solution for CVD is supplied while controlling the flow rate using the flow rate control method according to claim 13,
Disperse and vaporize the supplied raw material solution in a carrier gas,
A thin film forming method comprising performing CVD using the vaporized raw material solution to form a thin film.

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