JP2000058528A - Method and apparatus for vaporizing liquid raw material for CVD and CVD apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric film used for a semiconductor memory or the like by CVD
CV required for manufacturing by (chemical vapor deposition) method
A method and apparatus for vaporizing a liquid raw material that suppresses the generation of unvaporized residues in a vaporizer. SOLUTION: When a CVD liquid material for a ceramic film containing two or more elements is vaporized, generation of an unvaporized residue is produced by a combination of time-division feeding of materials corresponding to each element and microwave heating vaporization. To suppress the generation of particles that deteriorate the reproducibility of the film formation, prolong the continuous operation time of the vaporizer, and improve the productivity of the final semiconductor memory. In addition, it is possible to save space in the vaporizer by blocking a plurality of vaporizers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a thin film used for a semiconductor memory or the like, in particular, a dielectric film and a ceramic film. The present invention relates to a CVD apparatus using the same.

[0002]

2. Description of the Related Art In recent years, integration of memory devices in semiconductors has been rapidly progressing. For example, in a dynamic random access memory (hereinafter referred to as DRAM), the number of bits has been increased at a rapid rate of four times in three years. It has advanced. This is for the purpose of speeding up the device, reducing power consumption, reducing cost, and the like. However, no matter how the degree of integration is improved, the capacitor, which is a component of DRAM,
It must have a certain capacity. For this reason, it is necessary to reduce the film thickness of the capacitor material, and there has been a limit to the thinning of the SiO ₂ used up to that time. Therefore, if the dielectric constant can be increased by changing the material, the capacity can be ensured as in the case of thinning, so research using dielectric (high dielectric constant) materials for memory devices has recently attracted attention. I have. On the other hand, ferroelectric memories have attracted attention as one form of non-volatile memories that do not require power to retain storage. In this method, the polarization reversal, which is a material characteristic of a ferroelectric, is made to correspond to the presence or absence of memory. In addition to being nonvolatile, high-speed operation and high integration are possible depending on the improvement of the material characteristics.

As the performance required for such a capacitor material, it is important that the thin film has a high dielectric constant and a small leak current as described above. In addition, polarization characteristics are also important. That is, as long as a high dielectric constant material is used,
It is necessary to make the film as thin as possible and to minimize the leak current. The general development goals are generally SiO ₂
It is said that the equivalent film thickness is desirably 1 nm or less and the leak current density when applying 1.65 V is desirably 10 ^-8 A / cm ² or less. In addition, in order to form a thin film on the electrode of a DRAM capacitor having a step and on the electrode of a ferroelectric memory cell, it is possible to form a film by a CVD method which has good parallelism with a substrate having a complicated shape and has high productivity. Is very advantageous in the process. From such a viewpoint, tantalum oxide, lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), strontium titanate (ST), barium titanate (BT), barium strontium titanate (BST) , Bismuth tantalate
The formation of an oxide-based dielectric film such as strontium (SBT) has been studied using various film formation methods. In addition, since these oxide films are liable to deteriorate in characteristics at an interface with a metal electrode, an oxide conductive film and a specific metal may be used as an electrode in some cases.

[0004] Although it is most advantageous to form a film by the CVD method, there has been a serious problem that there is no CVD raw material having stable and good vaporization characteristics. This is mainly because the β-diketone-based dipivaloylmethane (DPM) compound, which is frequently used as a CVD raw material, has poor vaporization characteristics due to heating. It is considered to be a drawback caused by the above. Under these circumstances,
Some of the present inventors dissolve conventional solid raw materials in an organic solvent called tetrahydrofuran (THF) to form a solution, thereby significantly improving vaporization and composition controllability.
D raw material (JP-A-6-158328) and CV
D apparatus (Japanese Patent Laid-Open No. 6-310444) has been proposed, and it has become possible to obtain very good vaporization properties and composition controllability.

Recently, in order to further improve the productivity of memory manufacturing, countermeasures have been taken against residues slightly generated in conventional vaporizers. This is because particles resulting from the residue deteriorate the reproducibility of the film formation, shorten the continuous operation time of the vaporizer itself, and as a result, reduce the productivity of memory production. This residue is due to the fact that a conventional method has been used to vaporize using a single vaporizer in a state where raw material liquids corresponding to the respective elements are mixed in order to simplify the vaporizer, It is considered that the heating process in the state of the mixed liquid promotes the formation of the precursor and the polymer of the complex oxide having poor volatility. In order to solve this problem, the respective liquid raw materials may be vaporized by separate vaporizers and then mixed after gasification. Such a method and apparatus are disclosed in, for example, Japanese Patent Application Laid-Open No. 9-24 / 1990.
No. 1849. However, the easiness of forming the precursor and the multimer of the composite oxide varies depending on the type of the raw material, and it is not always necessary to vaporize all the raw materials independently.

[0006]

As described above, in the conventional vaporizing method and vaporizing apparatus, a vaporizing apparatus corresponding to each liquid raw material is prepared, and the vaporizing temperature is set to an optimum value for each raw material. It has become possible to reduce the generation of residues in the process. However, on the other hand, the number of vaporizers required is equal to the number of each raw material, and there is a disadvantage that the apparatus becomes complicated and large-scale. When the heating and vaporization of the liquid is performed only by the heater, it takes a certain period of time until the liquid reaches the vaporization temperature, and it is impossible to completely suppress the formation of a polymer having poor vaporization. This residue is
The particles reach the CVD reactor and cause film formation defects, and also hinder the elongation of the continuous operation time of the vaporizer. In addition, when preparing a plurality of conventional vaporizers for CVD liquid raw materials to perform independent vaporization of each raw material, it is necessary to uniformly mix each gas after vaporization, and a separate mixing device such as a gas mixer is required. There was a disadvantage.

The present invention has been made in order to solve the above-mentioned problems, and a plurality of raw materials are supplied to one vaporizer in a time-division manner, or a plurality of independent rooms are provided in one vaporizer. An object of the present invention is to provide a vaporization method, a vaporization apparatus, and a CVD apparatus using the same, which do not require many vaporizers. It is another object of the present invention to provide a vaporization method, a vaporization apparatus, and a CVD apparatus using the same, in which the efficiency of vaporization is improved by applying microwaves during vaporization.

[0008]

According to a first aspect of the present invention, there is provided a method for vaporizing a liquid material for CVD according to the first aspect of the present invention, wherein the supply amount is controlled in the method for vaporizing a liquid material for forming a thin film containing two or more elements. At least two of the respective liquid raw materials are fed into one vaporizer in a time-division manner, and the liquid raw materials are vaporized in the vaporizer.

According to a second aspect of the present invention, there is provided a method for vaporizing a liquid material for CVD according to the first aspect, wherein the step of feeding at least two materials into one vaporizer in a time-division manner further comprises the step of They are sent in time division.

According to a third aspect of the present invention, there is provided a method for vaporizing a liquid material for CVD according to the first aspect, wherein
Ba, Sr, and Ti specify that the raw materials to be fed to one vaporizer in a time-division manner are at least Ba and Sr.

According to a fourth aspect of the present invention, there is provided the method for vaporizing a liquid material for CVD according to the first aspect, wherein:
Pb, Zr, and Ti define that at least the raw materials to be fed into one vaporizer in a time-division manner are Pb and Zr.

According to a fifth aspect of the present invention, there is provided a method for vaporizing a liquid material for CVD according to the first aspect, wherein:
It is Sr, Bi, and Ta, and specifies that the raw materials to be fed into one vaporizer in a time sharing manner are at least Sr, Bi.

According to a sixth aspect of the present invention, there is provided an apparatus for vaporizing a liquid material for CVD, comprising a CV for forming a thin film containing two or more elements.
In a vaporizer provided with a vaporizer for vaporizing the D liquid raw material, at least one vaporizer is provided with a switching feeding means for feeding two or more liquid raw materials in a time-division manner.

According to a seventh aspect of the present invention, there is provided an apparatus for vaporizing a liquid material for CVD, comprising a vaporizer for vaporizing a CVD liquid material for forming a thin film, wherein the vaporized material is supplied in a controlled amount. And a microwave supply means for acting on the sprayed raw material.

According to the present invention, there is provided an apparatus for vaporizing a liquid material for CVD, comprising: a CV for forming a thin film containing two or more elements;
D In a vaporizer having a vaporizer for vaporizing a liquid raw material, at least two liquid raw materials whose supply amount is controlled among the liquid raw materials are independently sprayed and sent to an independent room in the one vaporizer. A plurality of spray nozzles, and a room for mixing the raw materials vaporized in the independent room.

According to a ninth aspect of the present invention, there is provided an apparatus for vaporizing a liquid material for CVD according to the eighth aspect, wherein a microwave supply means is provided in at least one room in the vaporizer.

According to a tenth aspect of the present invention, in the vaporization apparatus for a liquid source for CVD according to the eighth aspect, a mixing plate is provided between a room of the vaporizer into which the sprayed raw material is fed and a room for mixing. It stipulates that you have prepared.

[0018] A CVD apparatus according to claim 11 of the present invention is characterized in that:
7. An apparatus for controlling a supply amount of a liquid raw material supplied from a liquid raw material container, and an apparatus for vaporizing the liquid raw material supplied via the supply amount control means, wherein:
11. An apparatus for vaporizing a liquid material for CVD according to any one of items 1 to 10, and a reaction vessel for installing a substrate, feeding the vaporized material and depositing the vaporized material on the substrate. .

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have made improvements to the conventional vaporization method and vaporization apparatus, evaluated the residue in the vaporizer and the generation state of particles at the time of film formation, and conducted detailed studies. Invented the invention.

Embodiment 1 According to a first aspect of the present invention, there is provided a CVD method for a ceramic film containing two or more elements.
In the liquid material vaporizer, using one or more vaporizers, at least one of the vaporizers is provided with a liquid switching feed mechanism capable of performing time-division feed of two or more liquid raw materials, The time-division feeding of the liquid raw material is performed by a mechanism. Thereby, the same effect as in the case of performing vaporization using an independent vaporizer for each raw material can be obtained with a small number of vaporizers. Therefore, according to the present invention, the production of residues and particles in the vaporizer is suppressed without complicating the vaporizer portion, and the productivity is improved by improving the film formation reproducibility and extending the continuous operation time of the vaporizer. Improved.

Embodiment 2 FIG. In the second invention of the present invention, when the CVD liquid raw material for a ceramic film is vaporized, a combination of a spray nozzle for spraying the liquid raw material and a vaporizer for vaporizing the sprayed liquid raw material is used. The liquid material is completely vaporized by using microwave heating and vaporization together with the heat vaporization. While the conventional vaporizer indirectly heats and vaporizes the liquid raw material by an external heat source, the present invention combines the normal heating of the vaporizer wall with self-heating due to dielectric loss of the liquid raw material by microwave irradiation. This enabled vaporization with less residue generation. According to the present invention, the generation of residues and particles in the vaporizer is suppressed without complicating the vaporizer part, and the productivity is improved by improving the film formation reproducibility and extending the continuous operation time of the vaporizer. .

Embodiment 3 FIG. According to a third aspect of the present invention, there is provided a CVD method for a ceramic film containing two or more elements.
In an apparatus for vaporizing a liquid raw material, one vaporizer has a plurality of rooms each having a spray nozzle, and a mixing plate for preventing a backflow of vaporized gas on a raw material discharge side of the plurality of rooms, It has a raw material mixing chamber in which a plurality of chambers are connected via this mixing plate. As a result, the entire vaporizer can be made compact. In addition, since a mixing plate and a mixing chamber are provided inside the vaporizer, a gas mixer, which was conventionally required separately, is not required.

The first to third embodiments can be arbitrarily combined with each other. For example, in one room in the vaporizer of the third embodiment, the microwave irradiation of the second embodiment is used in combination. Alternatively, the time-division delivery as in the first embodiment may be performed from the spray nozzle only to one room in the vaporizer of the third embodiment. Alternatively, all of the first to third embodiments may be combined.

[0024]

The present invention will be described below in more detail with reference to specific examples.

Embodiment 1 FIG. 1 is a block diagram of a CVD apparatus showing an embodiment in which a CVD liquid material is vaporized by using the present invention and a BST-based dielectric film is formed as a ceramic film. Liquid raw materials for depositing Ba, Sr, and Ti are respectively filled with raw material containers 1a, 1b, 1
c, and the supply amount is set by the liquid supply devices 4a, 4b, and 4c. The raw materials (here, Ba and Sr) supplied via the liquid supply devices 4a and 4b are introduced into the spray nozzle 8 and the vaporizer 9 via the liquid switching and feeding mechanism 7.
The liquid switching feed mechanism 7 is an automatic valve that can switch the liquid flow path at a specific timing at a high speed, and switches the liquid at an interval of an arbitrary set time. It is possible to provide a fully closed state. Here, Ba and Sr are sequentially switched and supplied. On the other hand, the Ti raw material is introduced into the spray nozzle 8 and the vaporizer 9 after the supply amount is set by the liquid supplier 4c. At this time, all the raw materials are introduced in a liquid state up to the nozzle 8 and sprayed into a vaporizer heated by the nozzle 8. The raw material vaporized by the vaporizer 9 is introduced into a CVD gas nozzle 13 of a CVD reactor 12 having an exhaust device 16 via a raw material gas supply pipe 10. On the other hand, another reaction gas is also supplied from the reaction gas supply pipe 11, mixed with the raw material gas in the CVD gas nozzle 13, and is mixed with the desired BST onto the substrate 15 installed on the substrate heater 14.
A film is deposited and formed. In the present embodiment, two liquid sources can be switched, but if necessary, a large number of routes can be switched.

Each DPM-based raw material is dissolved in THF (tetrahydrofuran) to obtain a 0.1 mol / L concentration of Ba, S
Raw material liquids of r and Ti were prepared and used. Using the apparatus having the above configuration to which the present invention was applied, a comparison was made with a conventional method of vaporizing a ternary mixed liquid using 1 L of each raw material liquid at a vaporization temperature of 250 ° C. The switching timing of the liquid switching feeding mechanism 7 was set to 5 seconds. However, as it is B
Since the supply amounts of a and Sr are halved, Ba, Sr
The supply flow rate of r was set to twice that at the time of ternary mixing. FIG. 2 shows a timing chart at this time. Further, when the time ratio of the time-division feeding is different, it is necessary to appropriately adjust the supply amount according to the ratio so that the supply amount of the raw material per unit time becomes equal to that at the time of the mixed vaporization. As a result, the amount of residue generated in each vaporizer was significantly reduced, and the reproducibility of film formation (defects) due to particles was also reduced. In addition, the productivity of the final semiconductor memory has been improved by increasing the continuous operation time of the vaporizer. In the present embodiment, of the raw material liquids of Ba, Sr, and Ti, Ti, which is most likely to cause the generation of a non-vaporized residue when the mixed liquid is vaporized, is independently vaporized, and Ba and Sr are alternately fed and supplied. 3 with vaporizer
It has the same effect as each original independent vaporizer using two vaporizers. Thus, it is considered that the heating process in the mixed liquid state of the respective raw materials was eliminated, and the formation of the precursor and the multimer of the composite oxide having poor volatility was prevented.

On the other hand, since the deterioration of the film quality due to the alternate feeding of Ba and Sr tends to appear as the switching timing becomes longer, it may be appropriately selected according to the required film quality.
Further, as the switching timing is shorter, mixing in the liquid state at the nozzle portion occurs, and the generation of a residue is more likely to occur. Therefore, the problem of slight liquid mixing at the time of switching is that the fully closed state must be set for a short time during switching, or
A process for feeding a solvent for cleaning (for example, only THF) may be added, or a spray gas may be used for feeding the liquid. It is effective to set the fully closed state for a short period of time during switching, when the vaporizer side is in a depressurized state.
Due to this operation, the liquid between the liquid switching and feeding mechanism and the spray nozzle is sucked into the vaporizer and becomes a gap state. FIG. 3 shows a liquid switching feed mechanism 7 for Ba and Sr.
In the figure, 2 is a THF container, and 5 is a THF supply device. B
If THF is supplied as appropriate at the timing of switching between a and Sr, or only THF is supplied when no film is formed, the generation of residues can be suppressed and the generated residues can be eliminated.

Embodiment 2 FIG. FIG. 4 is a partial device configuration diagram in the case where one vaporizer is used in the first embodiment and all of Ba, Sr, and Ti are alternately vaporized by the liquid switching and feeding mechanism 7. Even in this case, in which the apparatus configuration is simplified as compared with the first embodiment, the generation of unvaporized residues is considerably reduced as compared with the conventional method of vaporizing a ternary mixed liquid, and the reproducibility of film formation due to particles is reduced ( The occurrence of defective products has been greatly reduced, and the productivity of the final semiconductor memory has been improved by extending the continuous operation time of the vaporizer. Further, by providing one more raw material supply device in the liquid switching and feeding mechanism 7 and adding a feeding process of a cleaning solvent (for example, only THF), the generation of residues was further reduced.

Embodiment 3 FIG. A CVD liquid source was vaporized by the vaporization method of the present invention using a vaporizer system having the same configuration as in Example 2, and a PZT-based dielectric film was formed. Each DPM raw material of Pb, Zr and Ti was dissolved in THF and the concentration was 0.05.
Each raw material liquid of mol / L was prepared. Film formation was performed at a vaporization temperature of 200 ° C. using 2 L of each raw material liquid. As a result, the generation of unvaporized residues is significantly reduced as compared with the conventional method of vaporizing a ternary mixed liquid, and the reduction in reproducibility of film formation (defects) due to particles is greatly reduced. As a result, the productivity of the final semiconductor memory is improved. This is because the vaporization method of the present invention eliminates the heating process in the mixed liquid state of the raw materials of Pb, Zr, and Ti, and prevents the formation of precursors and multimers of the composite oxide having poor volatility. Conceivable. The addition of a cleaning solvent (for example, only THF) feeding step further reduced the generation of residues.

In this embodiment, as in the first embodiment, Ti
By evaporating only the raw material alone, it is possible to more completely reduce unvaporized residues.

Embodiment 4 FIG. A CVD liquid source was vaporized by the vaporization method of the present invention using a vaporizer system having the same configuration as in Example 2, and an SBT-based dielectric film was formed. Each DPM raw material of Sr and Ta and triphenyl Bi were dissolved in THF to prepare each raw material liquid having a concentration of 0.05 mol / L.
Film formation was performed at a vaporization temperature of 220 ° C. using 1 L of each raw material liquid. As a result, as compared with the conventional method of vaporizing a ternary mixed liquid, the generation of unvaporized residues is reduced, and the reduction in reproducibility of film formation due to particles (generation of defective products) is greatly reduced, and the vaporizer By increasing the continuous operation time, the productivity of the final semiconductor memory has been improved. this is,
It is considered that the use of the vaporization method of the present invention eliminated the heating process in the mixed liquid state of the raw materials of Sr, Bi, and Ta, and prevented the formation of the precursor and multimer of the composite oxide having poor volatility. Further, a cleaning solvent (eg, THF)
Only), the formation of residues was further reduced.

Embodiment 5 FIG. An embodiment of the present invention will be described below with reference to the drawings. FIG. 5 shows an embodiment of the present invention.
It is a block diagram of an apparatus. Reference numeral 17 denotes a flow path for guiding a plurality of liquid raw materials to a vaporizer 19a via a spray nozzle 18, reference numeral 20 denotes a vaporizer heater installed inside the vaporizer 19a, reference numeral 21 denotes a vaporized gas outlet, and reference numeral 22 denotes a magnetron power supply 23. It is a magnetron oscillation tube to be operated. The CVD raw material vaporizer configured as described above was used as a vaporizer of a film forming apparatus. However, as shown in the figure, each raw material liquid was vaporized using a single vaporizer of the present invention after mixing.

The DPM raw material was dissolved in THF and the concentration was 0.1
Each raw material liquid of Ba / Sr / Ti of mol / L was prepared and used. A CVD apparatus having the same configuration as that of FIG. 1 except that there is no liquid switching and feeding mechanism and the vaporizer portion has the configuration of FIG. 3 was used, the flow rate of each raw material was 1 ml / min, and the heater temperature was 250.
Each 1 L of the liquid raw material was vaporized at a temperature of 500 ° C. and a microwave output of 500 W. As a result, even when the same ternary liquid mixture was vaporized, the vaporization apparatus using the vaporization method of the present invention significantly reduced residue generation in each vaporizer as compared with the conventional method.
This is because even when vaporization is caused by a heating process in a mixed liquid state of Ba, Sr and Ti, the liquid can be instantaneously heated and vaporized by concurrently using heating by microwaves, and the composite oxide having poor vaporization property is obtained. It is considered that the formation of the precursor and the multimer was inhibited.

In the above embodiment, the mixed liquid is vaporized by microwave heating. However, the use of a plurality of main vaporizers for the individual vaporization of each raw material liquid makes it possible to more accurately suppress the generation of residues. .

Embodiment 6 FIG. An embodiment of the present invention will be described below with reference to the drawings. FIG. 6 shows a CVD method according to an embodiment of the present invention.
It is a block diagram of an apparatus. In the present invention, one vaporizer 1
9b has a plurality of chambers each having a spray nozzle, and a mixing plate for preventing backflow of vaporized gas on the raw material discharge side of the plurality of rooms, and a raw material in which the plurality of chambers are connected via the mixing plate. It has a mixing chamber. In the figure,
24 and 26 are liquid material flow paths, 25 and 27 are spray nozzles,
28 and 29 are vaporization chambers, 30 is a mixing chamber, 31 is a vaporization chamber 2
The partition wall separating 8 and 29, and 32 are the respective vaporization chambers 2
This is a mixing plate for preventing the gas vaporized in 8 and 29 from flowing backward from the mixing chamber 30. A Ba, Sr-based raw material is introduced into the vaporizer 19b configured as described above, and a Ti-based raw material is introduced into another vaporizer 9 according to the first embodiment.
A T film was formed.

When a film formation experiment was performed using the apparatus of the present invention under the same conditions as in Example 1, the generation of residues in the vaporizer was significantly reduced, and the reproducibility of the film formation caused by particles was deteriorated. Good products). Further, by providing a mixing plate for preventing each vaporized gas from flowing back to each other at a downstream joint portion of the plurality of integrated vaporizer blocks and a mixing chamber for performing uniform gas mixing, the vaporizer is provided. This makes it possible to save space in the vaporizer without impairing the suppression of residue generation in the process. As a result, the continuous operation time of the vaporizer can be lengthened, and the productivity of the final semiconductor memory can be improved. As a structure of the mixing plate portion, a plate provided with a large number of pores as shown in FIGS.
A plate provided with a large number of thin tubes, a perforated plate having a three-dimensional network structure, and the like can be used. In FIG. 7, reference numeral 33 denotes a plate provided with a large number of pores, in FIG. 8, reference numeral 34 denotes a plate provided with a number of thin tubes, and in FIG. 9, reference numeral 35 denotes a perforated plate having a three-dimensional network structure.

In the present embodiment, the mixing plate and the mixing chamber at the downstream connecting portion of the plurality of vaporizer blocks are not provided, and the raw materials of each raw material can be simply connected and mixed near the vaporized gas outlet of each vaporizer. Independent vaporization and space saving of the vaporizer can be achieved. In this case, a slight residue is generated due to the backflow of the vaporized gas, and uniform mixing of the vaporized raw material gas becomes difficult. Therefore, it is better to provide a mixing plate and a mixing chamber as much as possible.

Embodiment 7 FIG. FIG. 10 is a partial configuration diagram of an apparatus showing another embodiment of the present invention. In the sixth embodiment, three raw materials can be introduced into one vaporizer 19c. In the vaporizer configuration of the present invention, reference numeral 36 denotes a liquid material flow path, 37 denotes a spray nozzle, and 38 denotes a vaporization chamber. A BST film forming experiment was performed using the thus-configured CVD material vaporizing apparatus as the vaporizing apparatus of the film forming apparatus shown in FIG.

In this embodiment, all raw materials of the raw material liquids of Ba, Sr, and Ti are independently vaporized. The DPM raw material is dissolved in THF, and the concentration of 0.2 mol / L Ba, Sr,
Each raw material liquid of Ti was prepared and used. Using the apparatus of the above configuration to which the present invention is applied, each one at a vaporization temperature of 250 ° C.
A comparison was made with a conventional method in which the ternary mixed liquid was vaporized using the L raw material liquid. As a result, the generation of the unvaporized residue was reduced to almost zero, and the reduction in the reproducibility of the film formation due to the particles (the generation of defective products) was greatly reduced. As a result, space saving of the vaporizer and reduction of residue generation can be simultaneously performed.

Embodiment 8 FIG. FIG. 11 is a partial configuration diagram of an apparatus according to another embodiment of the present invention, and shows a vaporizer 19d of the present embodiment.
In this example, the microwave source of the fifth embodiment is mounted on the vaporizer 19b of the sixth embodiment. Example 1 using the apparatus of the present invention
A BST film-forming experiment was performed under the same conditions as described above. It is to be noted that Ba and Sr are introduced into the main vaporizer 19d, and Ti is guided to another vaporizer. The heater temperature was 250 ° C. and the microwave output was 300 W. As a result, the generation of residues in the vaporizer was significantly reduced, and the decrease in reproducibility of film formation (defects) due to particles was reduced. In addition, a mixing plate for preventing each vaporized gas from flowing back to each other and a mixing chamber for performing uniform gas mixing are provided at a downstream side joint portion of the plurality of integrated vaporizer blocks, so that a single vaporization is performed. In addition, the space saving of the vaporizer can be achieved without impairing the suppression of residue generation in the vaporizer by microwave heating. As a result, the continuous operation time of the vaporizer can be lengthened, and the productivity of the final semiconductor memory can be improved.

[0041]

As described above, according to the first aspect of the present invention, at least one of the vaporizers included in the vaporizer of the CVD liquid source for forming a thin film containing two or more elements. Since a liquid switching feeding mechanism capable of performing time-division feeding of two or more liquid materials is provided in this method, and the time-division feeding of the liquid material is performed by this mechanism, at least two raw materials can be time-divisionally fed. In the step of feeding the solvent into one vaporizer, the solvent of the liquid raw material is further fed in a time-division manner, so that the generation of residues in the vaporizer is suppressed without complicating the vaporizer part, and This has the effect of suppressing the generation of particles that degrade the reproducibility of the film and increasing the continuous operating time of the vaporizer to improve the final productivity of the semiconductor memory. In addition, by using this method, at least Ba and Sr are supplied in a time-division manner using a liquid raw material corresponding to each element of Ba, Sr, and Ti to form a BST. This has the effect of suppressing the generation of residues in the vessel, suppressing the generation of particles that deteriorate the reproducibility of film formation, and increasing the continuous operation time of the vaporizer, thereby improving the final productivity of the semiconductor memory. Pb, Zr, T
Even if a PZT film is formed by using a liquid raw material corresponding to each element of i, at least Pb and Zr are supplied in a time-sharing manner,
Further, using a liquid raw material corresponding to each element of Sr, Bi and Ta, at least Sr and Bi are time-divisionally fed and
Even when the SBT film is formed, the same effect as when the BST film is formed can be obtained.

Further, in the second aspect of the present invention, when the CVD liquid material for forming a thin film is vaporized, a combination of a spray nozzle for spraying the liquid material and a vaporizer for vaporizing the sprayed liquid material is used. The liquid material is completely vaporized by using the vaporization of the spray liquid and the vaporization of the spray liquid in combination with the thermal vaporization by microwave. While the conventional vaporizer indirectly heats and vaporizes the liquid raw material by an external heat source, the present invention combines the normal heating of the vaporizer wall with self-heating due to dielectric loss of the liquid raw material by microwave irradiation. This enabled vaporization with less residue generation. According to the present invention, the generation of residues and particles in the vaporizer is suppressed without complicating the vaporizer part, and the productivity is improved by improving the film formation reproducibility and extending the continuous operation time of the vaporizer. .

According to a third aspect of the present invention, there is provided an apparatus for vaporizing a CVD liquid raw material for forming a thin film containing two or more elements, wherein one vaporizer has a plurality of spray nozzles each having a spray nozzle. The apparatus has a room and a mixing plate for preventing backflow of vaporized gas on the raw material discharge side of the plurality of rooms, and has a raw material mixing chamber in which a plurality of rooms are connected via the mixing plate. As a result, the entire vaporizer can be made compact. In addition, since a mixing plate and a mixing chamber are provided inside the vaporizer, a gas mixer, which was conventionally required separately, is not required. Then, there is an effect that the continuous operation time of the vaporizer can be lengthened and the productivity of the final semiconductor memory can be improved.

The vaporizer according to the first to third aspects of the present invention is denoted by C
When used in a VD device, the stability of the device can be compensated, the continuous operation time of the device can be extended, the characteristics of the formed film can be improved, and the productivity of the semiconductor memory can be improved. It has the effect of becoming.

[Brief description of the drawings]

FIG. 1 shows a C equipped with a vaporizer according to Embodiment 1 of the present invention.
FIG. 2 is a diagram illustrating a configuration of a VD device.

FIG. 2 is a schematic diagram showing a timing chart of raw material supply when the vaporizer according to Embodiment 1 of the present invention is used.

FIG. 3 is a diagram showing a configuration of a CVD apparatus provided with another vaporizer according to Embodiment 1 of the present invention.

FIG. 4 is a diagram showing a configuration of a vaporizer according to Embodiment 2 of the present invention.

FIG. 5 shows a C equipped with a vaporizer according to Embodiment 5 of the present invention.
FIG. 2 is a diagram illustrating a configuration of a VD device.

FIG. 6 shows a C equipped with a vaporizer according to Embodiment 6 of the present invention.
FIG. 2 is a diagram illustrating a configuration of a VD device.

FIG. 7 is a diagram showing a configuration of another vaporizer according to Embodiment 6 of the present invention.

FIG. 8 is a diagram showing a configuration of still another vaporizer according to Embodiment 6 of the present invention.

FIG. 9 is a diagram showing a configuration of still another vaporizer according to Embodiment 6 of the present invention.

FIG. 10 is a diagram showing a configuration of a vaporizer according to Embodiment 7 of the present invention.

FIG. 11 is a diagram showing a configuration of another vaporizer according to Embodiment 8 of the present invention.

[Explanation of symbols]

1a, 1b, 1c liquid raw material container, 2 liquid raw material container, 4a, 4b, 4c liquid supply device, 5 liquid supply device, 7 liquid switching feeding mechanism, 8 spray nozzle,
Reference Signs List 9 vaporizer, 10 source gas supply pipe, 11 reaction gas supply pipe, 12 CVD reactor, 13 CVD gas nozzle, 14 substrate heater, 15 substrate, 16 evacuation, 17 liquid source flow path, 18 spray nozzle, 1
9, 19a, 19b, 19c, 19d vaporizer, 20
Vaporizer heater, 21 vaporized gas outlet, 22 magnetron oscillation tube, 23 power supply for magnetron, 24,
26, 36 liquid material flow path, 25, 27, 37 spray nozzle, 28, 29, 38 vaporization chamber, 30 mixing chamber,
31 vaporization chamber partition wall, 32 mixing plate, 33 plate provided with many pores, 34 plate provided with many thin tubes, 35
A perforated plate with a three-dimensional network structure.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Umemura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Inventor Hideko Uchikawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F term in Mitsubishi Electric Corporation (reference) 4K030 BA01 BA04 BA18 BA22 EA01 JA05 KA41 5F045 AB40 BB08 BB15 EE02 EE05

Claims (11)

[Claims] 1. A CV for forming a thin film containing two or more elements.
D In the method for vaporizing a liquid raw material, at least two of the liquid raw materials whose supply amounts are controlled are fed to one vaporizer in a time-division manner, and the liquid raw material is vaporized in the vaporizer. Of a liquid material for CVD. 2. The CVD liquid according to claim 1, wherein in the step of feeding at least two raw materials to one vaporizer in a time-division manner, a solvent of a liquid raw material is further fed in a time-division manner. Raw material vaporization method. 3. The CVD liquid raw material is Ba, Sr, Ti, and the raw material fed into one vaporizer in a time-division manner is:
2. The device according to claim 1, wherein at least Ba and Sr.
4. The method for vaporizing a CVD liquid raw material according to item 1. 4. The CVD liquid raw material is Pb, Zr, Ti, and the raw materials fed into one vaporizer in a time-sharing manner are:
2. The method according to claim 1, wherein at least Pb and Zr.
4. The method for vaporizing a CVD liquid raw material according to item 1. 5. The CVD liquid raw material is Sr, Bi, Ta, and the raw material fed into one vaporizer in a time-sharing manner is:
2. The semiconductor device according to claim 1, wherein at least Sr, Bi.
4. The method for vaporizing a CVD liquid raw material according to item 1. 6. A CV for forming a thin film containing two or more elements.
D. A vaporizer comprising a vaporizer for vaporizing a liquid source, wherein at least one vaporizer comprises a switching feed means for feeding two or more liquid sources in a time-division manner. Raw material vaporizer. 7. A vaporizing apparatus provided with a vaporizer for vaporizing a CVD liquid raw material for forming a thin film, a spray nozzle for spraying the raw material whose supply amount is controlled into the vaporizer and feeding the vaporized raw material to the vaporizer. And a microwave supply means acting on the liquid material. 8. A CV for forming a thin film containing two or more elements.
D In a vaporizer having a vaporizer for vaporizing a liquid raw material, at least two liquid raw materials whose supply amount is controlled among the liquid raw materials are independently sprayed and sent to an independent room in the one vaporizer. A vaporizer for a liquid source for CVD, comprising: a plurality of spray nozzles for performing a process and a room for mixing the materials vaporized in the individual chambers in a vaporizer. 9. The apparatus for vaporizing a liquid material for CVD according to claim 8, wherein a microwave supply means is provided in at least one room in the vaporizer. 10. The apparatus for vaporizing a liquid material for CVD according to claim 8, wherein the vaporizer is provided with a mixing plate between a room into which the sprayed raw material is fed and a room for mixing. . 11. A supply amount control means for controlling a supply amount of a liquid material supplied from a liquid material container, and an apparatus for vaporizing the liquid material supplied via the supply amount control means, CV according to any one of Items 6 to 10
A CVD apparatus, comprising: an apparatus for vaporizing a liquid raw material for D; and a reaction vessel for installing a substrate, feeding the vaporized raw material, and depositing the vaporized raw material on the substrate.