JPH10152779A - Vaporizer and cvd system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a stable vaporizing raw material without causing a time change and furthermore to form a high quality coating for a wide application. SOLUTION: In a casing body 11 for forming a vaporizing raw material is, one side wall is provided with an atomizer 13 for forming foggy droplets 12 having about 100μm average dize from a liq. raw material and a gas feed tube 16 for carrying feeding a gas 15 for carrying composed of a chemically inert gas for carrying the formed droplets 12 or the vaporizing raw material 14 into the casing body 11. The opposite other side wall is provided with a vaporizing raw material 14 carrying tube 17 carrying the vaporizing raw material 14 mixed to the gas for carrying. The upper part within the casing body 11 is provided with a microwave oscillator 19 forming the vaporizing raw material 14 by oscillating microwaves 18 on the foggy droplets 12, generating oscillation on molecules composing the droplets 12 and executing heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming apparatus for forming various thin films by a chemical vapor deposition (hereinafter, abbreviated as CVD) method, and in particular, a liquid material is vaporized and supplied to the thin film forming apparatus. The present invention relates to a vaporizer and a CVD apparatus using the vaporizer.

[0002]

2. Description of the Related Art In recent years, high density and high integration of semiconductor devices have been rapidly progressing. For example, the integration degree of a semiconductor memory represented by a random access memory (= DRAM) is constantly improving. is there. However, in a DRAM, the amount of charge stored in each cell needs to maintain a substantially constant value regardless of the degree of integration. In a conventional DRAM, the charge amount is maintained at a constant value by reducing the thickness of a silicon oxide film serving as a capacitance film. However, since the thinning is approaching its limit, the capacitance is secured by a different approach. The need has come. As a countermeasure, there is a movement to use a material having a high dielectric constant for the capacitance film. For example, in a 1 Gbit DRAM, the use of tantalum oxide having a relative dielectric constant of about 25 is considered promising, and 1 Gbit
For DRAMs exceeding t, the use of barium strontium titanate (= BST) or lead zirconate titanate (= PZT) having a relative dielectric constant of several hundred or more is considered to be effective.

Generally, to form a BST or PZT capacitance film on a capacitor electrode having a step on a DRAM substrate, it is most effective to use a CVD method with good coverage. Previously, a raw material gas for BST or PZT was obtained by sublimating a metal complex material coordinated with β-diketone-based dipivaloylmethane (= DPM) or the like.
In recent years, in order to stably supply a source gas, a method of dissolving these metal complex materials in a solvent and evaporating a solution of the metal complex material to obtain a source gas has become mainstream.

[0004] Such a conventional solution evaporation type CVD.
An example of the apparatus is a CVD apparatus disclosed in JP-A-7-94426.

A conventional solution vaporization type CVD apparatus will be described below with reference to the drawings.

FIG. 6 is a sectional view showing the structure of a conventional CVD apparatus. As shown in FIG. 6, the present CVD apparatus is roughly divided into a vaporizer 101 for generating a vaporized raw material and a reaction furnace 150 for heating and reacting the vaporized raw material supplied from the vaporizer 101.

In a vaporizer 101 having a vaporization chamber 102 for vaporizing a liquid raw material, a heater 103 for heating the vaporizer 101 to a predetermined temperature is embedded inside a wall material around the vaporization chamber 102. Further, the vaporizer 101 includes a vaporization chamber 1.
The tapered narrow tube 104 having a tapered constriction portion 104a at the tip thereof for causing the diluent gas, which carries the vaporized raw material generated in 02 to the reaction furnace 150, to flow into the vaporization chamber 102 at a high speed, and is generated in the vaporization chamber 102. A raw material gas transport pipe 105 for supplying the vaporized raw material to the reaction furnace 150 is connected. Source gas transport pipe 1 in vaporization chamber 102
A filter 106 for filtering foreign matter mixed in the vaporized raw material is provided in the vicinity of the opening 05. Around the source gas transport pipe 105, a heater 107 for keeping the temperature at a predetermined temperature is provided in a helical manner at a predetermined interval in order to prevent re-condensation of the vaporized raw material caused by the temperature drop below the predetermined temperature. .

[0008] The upstream end of the tapered thin tube 104 is connected to a diluent gas supplier 110 for adjusting the flow rate of the diluent gas. Further, inside the tapered thin tube 104, a liquid source supply pipe 111 for supplying a liquid source to the vaporization chamber 102 is provided so as to extend in the axial direction from the center of the tapered thin tube 104. The downstream end of the liquid material supply pipe 111 is opened as a nozzle 111a at the downstream end of the narrowed portion 104a of the tapered narrow tube 104, and the upstream end of the liquid material supply pipe 111 is
In the vicinity of the upstream end of the tapered thin tube 104, the tapered thin tube 1 is bent outward in the radial direction of the tapered thin tube 104.
04 penetrates from the inside to the outside, and is connected to a liquid raw material supply device 112 for adjusting the flow rate of the liquid raw material. The upstream side of the liquid raw material supply device 112 is connected to a raw material container 113 that stores the liquid raw material. An upper part of the raw material container 113 is connected to a pumping gas pipe 114 for feeding the liquid raw material to the liquid raw material supply device 112.

A substrate holding table 152 for holding a substrate 151 is provided inside the reaction furnace 150, and a reaction furnace heating means 153 for heating the reaction path 150 is provided on a side wall of the reaction furnace 150. At the upper part, a reaction gas transport pipe for supplying a reaction gas to be reacted with the vaporized raw material into the reaction furnace 150 is provided.

Hereinafter, the conventional CV constructed as described above will be described.
The operation of the D device will be described.

First, the liquid raw material in the raw material container 113 is pressurized by the pressurized gas sent through the pressurized gas pipe 114, and the flow rate of the pressurized liquid raw material is adjusted by the liquid raw material supply unit 112. After that, the liquid raw material supply pipe 1
11 and is sent to the tip of the nozzle 111a.

On the other hand, the diluent gas whose flow rate has been adjusted by the diluent gas supply device 110 is sent to the tapered thin tube 104, and the diluent gas increases its flow velocity at the narrowed portion 104 a at the tip of the tapered thin tube 104. As a result, the liquid raw material exiting from the tip of the nozzle 111a by the diluent gas having a high flow velocity becomes fine droplets and is injected into the vaporization chamber 102 of the vaporizer 101. Since the vaporizer 101 is heated to, for example, 200 ° C. by the heater 103, the liquid material composed of the ejected droplets touches the inner wall of the vaporizing chamber 102 or is vaporized by radiant heat of the inner wall. The vaporized source gas passes through the filter 106 and is supplied to the reaction furnace 150 through the source gas transport pipe 105 kept warm by the heater 107 for preventing dew condensation.

The filter 106 is connected to the vaporizing chamber 102.
It is provided in order to re-evaporate or trap fine particles of liquid material that have not sufficiently vaporized or solidified particles. The reactor heating means 153 for preventing the vaporized raw material from dew condensation on the side wall of the reactor 105 also.
Is set to a predetermined temperature. Further, for example, oxygen gas as an oxidant is supplied to the reaction furnace 150 through a reaction gas transport pipe 154 of a different system from the source gas transport pipe 105. Thus, when the substrate 151 on which a film is to be formed is placed on the substrate holding surface of the substrate holding table 152 and the temperature of the substrate 151 is raised to a temperature equal to or higher than the decomposition temperature of the raw material gas, decomposition and oxidation of the raw material gas are performed on the surface of the substrate 151. Because they proceed simultaneously, the substrate 151
An oxide thin film is formed on the surface of.

Further, in this conventional example, the vaporizer 101 is provided on the reactor 150 so that the temperature of the raw material gas transport pipe 1 is strictly controlled.
It is also mentioned that 05 can be omitted.

[0015]

However, in the conventional solution vaporization type CVD apparatus, the liquid material is vaporized by touching the inner wall surface of the heated vaporization chamber 102 and by radiant heat from the inner wall surface. Therefore, it is difficult to uniformly vaporize. As a result, the liquid raw material is not sufficiently vaporized in the vaporization chamber 102, or conversely, the liquid raw material is decomposed due to overheating to produce a solid precipitate. To cope with this, conventionally, a filter 106 for re-evaporating the liquid raw material or trapping solid precipitates is used.
However, since the filter 106 needs to be periodically replaced, the CVD apparatus for mass production has the following problems.

That is, since solidified particles remain in the vaporizer 101 itself, it is necessary to periodically clean or replace the vaporizer 101.

In addition, since the supply pressure of the raw material gas changes with time in the filter 106 in accordance with the trapping state, the film forming speed changes. The part to rely on becomes larger.

Further, in a CVD apparatus having a structure in which the vaporizer 101 and the reaction chamber furnace 150 are directly connected, it is required to completely vaporize the liquid raw material. When aiming and heating so that the liquid raw material near the center is vaporized, the temperature becomes too high on the side near the inner wall surface of the vaporization chamber 102, and the vaporized raw material is decomposed, which causes generation of particles. .

An object of the present invention is to solve the above-mentioned conventional problems at a glance, to produce a stable vaporized raw material without a change over time and to form a general-purpose and high-quality film. .

[0020]

In order to achieve the above-mentioned object, the present invention provides a method for producing a vaporized material by oscillating microwaves into mist-like droplets using a microwave oscillator and heating the droplets. Is generated.

[0021] Specifically, a solution taken by the invention of claim 1 is that a vaporizer is supplied with a liquid raw material, and a sprayer that converts the supplied liquid raw material into mist-like droplets; And a microwave oscillator for generating vaporized raw material by generating vibration and heating molecules constituting the droplet.

According to the first aspect of the present invention, the droplets made of the atomized liquid raw material generated by the atomizer are irradiated with the microwave oscillated by the microwave oscillator and heated to vaporize the droplets. The liquid droplets can be uniformly heated, so that no liquid or solid residue is generated inside the apparatus.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, a configuration further comprising a heat retaining means for keeping the vaporized raw material at a temperature higher than a reliquefaction point and lower than a decomposition point of the vaporized raw material is added. It is.

According to a third aspect of the present invention, in addition to the first aspect, a configuration in which the solvent of the liquid raw material contains a polar molecule is added.

According to a fourth aspect of the present invention, in addition to the structure of the third aspect, the solvent has a structure represented by the general formula ROH (where R is an alkyl group).

According to a fifth aspect of the present invention, in the configuration of the fourth aspect, the frequency of the microwave oscillated by the microwave oscillator is:
A configuration in which the frequency is 1 GHz or more and 5 GHz or less is added.

According to a sixth aspect of the present invention, the organic metal dissolved in the liquid material contains a polar molecule in addition to the first aspect.

According to a seventh aspect of the present invention, in the constitution of the sixth aspect, the organic metal is represented by a general formula (RO) _n M (where R is an alkyl group, M is a metal element, and n is a natural number). This is to add a configuration to be performed.

According to an eighth aspect of the present invention, in the constitution of the sixth aspect, the organic metal is represented by the general formula M [I ₃ CCOCHCOCI ₃ ] _n
(However, M is a metal element, n is a natural number, and I is a hydrogen group, an alkyl group, or an electron-withdrawing group).

According to a ninth aspect of the present invention, in the constitution of the eighth aspect, the electron-withdrawing group is -NH ₃ , -NR ₃ (where R is an alkyl group), -NO ₂ , -CN,-. COOR (where R is an alkyl group), -COOH, -CH
O, -COR (where R is an alkyl group), -C
_{HCH 2, -C 6 H 5,} -CCH, -CH 2 Cl, -O
H, -OR (where R is an alkyl group), -F,
-Cl, in which adding a configuration including at least one of -Br and -CF _3.

The solution taken by the invention of claim 10 is C
A VD device provided in the reactor and the reactor;
A substrate holder that holds the substrate and heats the held substrate, a sprayer that atomizes the liquid source into mist-like droplets and sprays the liquid onto the substrate holder, and oscillates microwaves on the droplets, A microwave generator that generates a vaporized raw material by generating vibrations and heats the molecules constituting the droplets and supplies the vaporized raw material to the surface of the substrate is provided.

According to the tenth aspect of the present invention, the droplets made of the atomized liquid raw material generated by the atomizer are irradiated with the microwave oscillated by the microwave oscillator and heated to vaporize the droplets. The liquid droplets can be uniformly heated, so that no liquid or solid residue is generated inside the apparatus.

Further, since the vaporization of the liquid raw material is heated by using microwaves in the reaction furnace, a vaporizer becomes unnecessary.

According to an eleventh aspect of the present invention, in addition to the configuration of the tenth aspect, a configuration is provided in which the reactor has a heat retaining means for keeping the vaporized raw material warm so that the vaporized raw material is not reliquefied. .

According to a twelfth aspect of the present invention, in addition to the configuration of the tenth aspect, a configuration is provided in which the reaction furnace has a reaction gas supply pipe for supplying a reaction gas reacting with the vaporized raw material into the reaction furnace. Is what you do.

According to a thirteenth aspect of the present invention, in addition to the configuration of the twelfth aspect, a configuration is provided in which the reaction gas contains at least one of O ₂ , NO, N ₂ O, and O ₃ .

According to a fourteenth aspect of the present invention, in the configuration of the tenth aspect, the microwave transmitter is configured to irradiate the vaporized raw material with a microwave for decomposing a part of molecules constituting the vaporized raw material. Things.

According to a fifteenth aspect of the present invention, in addition to the configuration of the tenth aspect, a configuration further provided with an airflow control means provided above the substrate holding table and for equalizing the concentration of the vaporized raw material is added. Things.

According to a sixteenth aspect of the present invention, in the configuration of the fifteenth aspect, the airflow control means has a center axis perpendicular to the substrate holding surface of the substrate holding table, and the diameter increases as the diameter approaches the substrate holding surface. It has a frusto-conical shape, and has a configuration in which a plurality of cylindrical bodies having different inner diameters and concentric cross sections in the radial direction are added.

The invention of claim 17 is the invention of claim 15 or 16
In the above structure, the airflow control means may further include a structure in which the temperature of the vaporized raw material is maintained at a temperature equal to or higher than a reliquefaction point and equal to or lower than a decomposition point.

According to an eighteenth aspect of the present invention, in addition to the configuration of the tenth aspect, a configuration is provided in which the solvent of the liquid raw material contains a polar molecule.

According to a nineteenth aspect of the present invention, in addition to the structure of the eighteenth aspect, the solvent has a structure represented by a general formula ROH (where R is an alkyl group).

According to a twentieth aspect, in addition to the configuration of the nineteenth aspect, a configuration is provided in which the frequency of the microwave oscillated by the microwave oscillator is 1 GHz or more and 5 GHz or less.

According to a twenty-first aspect of the present invention, the organic metal dissolved in the liquid raw material contains a polar molecule in addition to the tenth aspect.

According to a twenty-second aspect of the present invention, in the constitution of the twenty-first aspect, the organic metal is represented by a general formula (RO) _n M (where R is an alkyl group, M is a metal element, and n is a natural number). This is to add a configuration to be performed.

According to a twenty- _third aspect of the present invention, in the constitution of the twenty-first aspect, the organic metal is represented by the general formula M [I ₃ CCOCHCOCI
₃ ] _n (where M is a metal element, n is a natural number, and I is a hydrogen group, an alkyl group or an electron withdrawing group).

According to a twenty-fourth aspect of the present invention, in the constitution of the twenty- _{third aspect} , the electron-withdrawing group is -NH ₃ , -NR ₃ (where R
Is an alkyl group. _{), - NO 2, -CN,} -COO
R (where R is an alkyl group), -COOH,-
CHO, -COR (where R is an alkyl group),
_{-CHCH 2, -C 6 H 5,} -CCH, -CH 2 Cl, -
OH, -OR (where R is an alkyl group),-
F, is intended to add -Cl, a structure including at least one of among -Br and -CF _3.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) A first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view showing the structure of the vaporizer according to the first embodiment of the present invention. As shown in FIG. 1, a casing 11 for generating a vaporized raw material has, on one side wall thereof, a sprayer 13 that generates mist-like droplets 12 having an average diameter of about 100 μm from a liquid raw material. Drop 1
2 or a chemically inert gas for transporting the vaporized raw material 14, for example, a transport gas 15 made of Ar gas.
1 and a carrier gas supply pipe 16 for supplying the gas to the inside. Further, on the other side wall opposite thereto, a vaporized raw material transport pipe 17 for transporting the vaporized raw material 14 mixed with the transport gas 15 is provided.
Is provided. On the upper part of the inside of the housing 11, a microwave 18 is oscillated in the mist droplet 12, and vibration is generated in molecules constituting the droplet 12 to heat the vaporized raw material 14.
Is provided. Microwave oscillator 19 is 1 GHz to 5 GHz depending on the raw material.
An appropriate frequency can be oscillated between z. Also,
On the outer peripheral surfaces of the casing 11 and the vaporized raw material transport pipe 17, a heat retaining heater 20 is provided as a heat retaining means for keeping the generated vaporized raw material from being reliquefied.

The supply side of the atomizer 13 is connected to a liquid source supply 21 composed of, for example, a pump through a pipe, and the introduction side of the liquid source supply 20 is connected to a liquid source container 22 through a pipe. The liquid material container 22 contains, for example, a liquid material obtained by dissolving Ti (Oi-Pr) ₄ in isopropyl alcohol (hereinafter abbreviated as IPA).

The sprayer 13 may have any structure as long as it has a function of spraying the liquid raw material in the form of a mist. For example, atomization may be performed by flowing a high-speed dilution gas around a nozzle whose tip is obliquely cut as shown in the conventional example.

In this embodiment, the nebulizer 13 is used.
And the carrier gas supply pipe 16 is provided on the side wall, and the microwave transmitter 19 is provided at the upper part in the housing 11. However, the present invention is not limited to this, and the sprayer 13 and the carrier gas supply pipe 16 are provided at the upper part. The vessels 19 may be provided on the respective side walls.

Hereinafter, the operation of the vaporizer configured as described above will be described. First, the flow rate of the liquid raw material accommodated in the liquid raw material container 22 is adjusted by the liquid raw material supply device 21 and supplied to the sprayer 13. Injected into. A microwave 18 oscillated by a microwave oscillator 19 is output in the ejection direction of the droplet 12. The droplets 12 are heated and vaporized by being irradiated with the microwaves 18 to generate vaporized raw materials 14. Vaporized raw material 1 generated
4 is mixed with the carrier gas 15 in the housing 11 and transported outside through the vaporized raw material transport pipe 17.

The molecules whose vibration is excited by the microwave must have polarity as a whole.
That is, it is necessary that the organic metal or the solvent thereof, which is a solute of the liquid raw material, has polarity.

Examples of the solvent containing a polar molecule include a so-called alcohol represented by the chemical formula ROH in which R is an alkyl group.

On the other hand, as organic metals containing polar molecules, R is an alkyl group, M is a metal element, n is a natural number,
There is a so-called alkoxide material represented by the chemical formula (RO) _n M. The chemical formula M [I ₃ CCOCHCOCI
₃ ] There is a β-diketone compound represented by _n , wherein I is a group selected from an —H group, an alkyl group and an electron-withdrawing group so that the organic metal has polarity. As examples of electron withdrawing _{groups, -NH 3, -NR 3, -NO} 2, -C
N, -COOR, -COOH, -CHO, -COR,-
_{CHCH 2, -C 6 H 5,} -CCH, -CH 2 Cl, -
OH, -OR, -F, -Cl, include -Br, or -CF _3.

The temperature of the droplets 12 can be raised by setting the frequency of the microwaves 18 transmitted from the microwave transmitter 19 to a frequency value that causes the solvent or the organic metal polar molecule to vibrate. In the present embodiment,
Heating a solvent whose concentration ratio is overwhelmingly larger than that of a solute can increase the temperature more efficiently.
When A is used, the frequency of the microwave 18 is set to 3 GHz where the vibration efficiency is highest. It should be noted that Ti (Oi-Pr) ₄ is used for the organic metal and IPA is used for the solvent in consideration of availability and cost in consideration of the material.

Here, if the intensity of the microwave 18 is too high, some of the molecules of the vaporized raw material 14 will be decomposed. For example, before the vaporized raw material 14 is transported to a reaction furnace (not shown), May be precipitated. For this reason, by adjusting the output of the microwave transmitter 19, a favorable vaporization state is obtained as an output capable of realizing optimal vaporization, for example, an output of 1 kW.

As described above, according to the present embodiment, since the mist-like liquid raw material is heated by using the microwave 18 transmitted from the microwave transmitter 19, the microwave oscillator 19 is used.
Since the temperature of the liquid raw material flowing near and the temperature of the liquid raw material flowing far away are similarly increased, the mist-like liquid raw material can be uniformly heated. As a result, the liquid raw material can be uniformly vaporized, so that no raw material remains in a liquid state without being vaporized, and no solid precipitates due to overheating. As a result, it is not necessary to replace the filter and remove the solid matter in the vaporizer, which is required in the past. In the CVD apparatus using the vaporizer, maintenance is easy even during mass production, and the operation time of the apparatus is reduced. Increase.

Further, no pressure loss occurs in the vaporizer,
Since there is no longer a factor accompanied by a change in the supply amount over time, the supply amount of the vaporized raw material is controlled by the supply amount of the liquid raw material, so that stable supply of the vaporized raw material can be always performed.

Incidentally, an electromagnetic wave shield may be provided on the housing 11 in order to block electromagnetic wave noise caused by the microwaves 18. The electromagnetic wave shield only needs to have an electromagnetic wave shielding property, and may be, for example, aluminum, gold, silver, copper, or an alloy thereof. Further, the housing 11 itself may be configured to shield electromagnetic waves.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows a CV according to a second embodiment of the present invention.
It is a schematic cross section which shows the structure of D apparatus. In FIG.
The same members as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 2, a reaction furnace 31 for heating and reacting a vaporized raw material is provided with a substrate holding table 32 having a heating means (not shown) such as a sheath resistance heater at the center of the bottom surface thereof. Holder 32
A substrate 33 made of, for example, silicon, which is a film formation target, is held on the substrate holding surface. An atomizer 13 for generating mist-like droplets 12 from a liquid raw material and a vaporized raw material 14 generated above a substrate holding table 32 in an upper part of the reactor 31.
And a reaction gas supply pipe 35 for supplying a reaction gas 34 such as oxygen gas, which reacts with the reaction gas, into the furnace. On the inner wall of the reactor 31, the microwave 18
And a microwave oscillator 19 that generates the vaporized raw material 14 by generating vibration and heating molecules constituting the droplet 12. The outer wall of the reactor 31 is provided with a reactor heating means 36 as a heat retaining means for keeping the temperature of the furnace itself by circulating oil heated therein so that the vaporized raw material is not reliquefied. Reactor 31
An exhaust pipe for exhausting the unreacted vaporized raw material 14, the reaction gas 34 or the unnecessary gas generated by the reaction to the outside of the furnace is provided at the bottom of the exhaust pipe, and the exhaust pipe is connected to an exhaust means 37 such as a pump. .

Hereinafter, the operation of the above-configured CVD apparatus will be described. First, the liquid source container 22 contains a liquid source using Ti (Oi-Pr) ₄ as an organic metal and IPA as a solvent. The liquid source is supplied to the atomizer 13 by the liquid source supplier 12, and the supplied liquid source ejects the mist-like droplets 12 into the reaction furnace 31 by the atomizer 13. The ejected droplet 12 is heated by the microwave 18 oscillated from the microwave oscillator 19 to cause molecular vibration of polar molecules of the solvent, for example, IPA. ,
It becomes the vaporized raw material 14. The vaporized raw material 14 is supplied to the reaction gas supply pipe 3
The gas is mixed with the reaction gas 34 supplied from 5 and reaches the surface of the substrate 33. The substrate 33 is heated by the heating means of the substrate holder 32, and is heated to a temperature at which the vaporized raw material 14 is decomposed and a film in a desired crystalline state is obtained. In the present embodiment, the temperature of the substrate 33 is set to 550 ° C. at which titanium oxide having a small crystal grain size grows.

In the prior art, the atomizer 13 was directly connected to the reaction furnace 31. However, since radiation heating was performed by a heater or the like, the mist-like liquid material Vaporization state is different. In particular, when vaporized directly in the reaction furnace 31, it is necessary to vaporize all of the mist-like liquid raw material. Therefore, the mist-like liquid raw material, to which radiant heat is difficult to reach, is heated so as to be sufficiently vaporized. Therefore, in the peripheral portion, the temperature is excessively increased, and the vaporized raw material is decomposed, and as a result, particles may be generated. On the other hand, according to the CVD apparatus of the present embodiment, since the heating is performed using the microwave, the mist-like liquid raw material can be uniformly heated, so that generation of particles can be prevented.

If the temperature of the inner wall of the reaction furnace 31 is lower than the dew point (= reliquefaction point) of the vaporized raw material 14, reliquefaction may occur on the wall surface.
In some cases, component elements are precipitated as they remain in or degenerate within 1, and particles may be generated. If the particles enter the film being formed, the quality of the film is impaired. Therefore, the vaporized raw material 14 is heated using the reactor heating means 36 provided on the outer wall of the reactor 31 so as not to reliquefy. It is necessary to set the temperature in the furnace according to the type of the liquid raw material.
° C.

The CVD apparatus according to the present embodiment
Since the liquid source is vaporized and formed into a film in the chamber 1, clogging of the vaporizer and replacement due to the clogging as in the related art are not required, so that long-term continuous use is possible. As a result, not only the efficiency of film formation is improved, but also the cost is reduced. FIG.
The need for temperature control of the vaporized raw material transport pipe 17 is also eliminated because the vaporized raw material transport pipe 17 shown in (1) is unnecessary, which simplifies the apparatus configuration and control of the apparatus, and causes troubles such as clogging of the vaporized raw material transport pipe 17. No longer.

Further, since the mist-like liquid raw material is heated by using the microwave 18, the mist-like liquid raw material can be heated uniformly, so that a homogeneous vaporized raw material can be produced. Thereby, the quality of the formed film can be improved.

In the first embodiment, if the intensity of the microwave 18 is too high, the constituent elements of the vaporized raw material 14 may be precipitated before being transported to the reaction furnace. In the CVD apparatus, since the distance from the vaporization to the substrate 33 is short, the problem of deposition hardly occurs. Rather, by increasing the intensity of the microwave 18, the decomposition of the vaporized raw material 14 is promoted, so that the substrate 33 on which devices and wiring are already formed is not damaged by heat. A film having good crystallinity can be quickly formed at a low temperature. That is, in the present CVD apparatus, when the intensity of the microwave 18 is, for example, 2 kW, the substrate temperature is 450 ° C., and the film forming speed is 10
Even in the case of nm / min, a film in a favorable crystalline state can be obtained.

As described above, according to the present embodiment, the vaporized raw material 14 is generated from the liquid raw material by heating the atomized droplet 12 using the microwave 18 in the reaction furnace 31. Since a vaporizer becomes unnecessary, the apparatus configuration and control of the apparatus are simplified, maintenance is simplified, and the mist-like droplets 12 are uniformly heated, so that the liquid raw material is uniformly vaporized. Solid components do not precipitate before reaching the substrate 33 on which a film is to be formed, and a high-quality film can be formed.

In order to further promote lowering of the film formation temperature, a mechanism capable of applying a high-frequency electric field to the vaporized gas or the reaction gas may be provided to generate plasma.

In this embodiment, titanium oxide is used as the metal oxide. However, when the oxide is not used as a film-forming target, it is not necessary to introduce oxygen gas as the reaction gas 34 into the furnace. Needless to say.

(Third Embodiment) Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

FIG. 3A is a schematic sectional view showing the structure of a CVD apparatus according to the third embodiment of the present invention. FIG.
In FIG. 2A, the same members as those shown in FIG. As shown in FIG. 3, above the substrate holding table 32 in the reaction furnace 31,
A frustoconical airflow control means 41 having a central axis extending in a direction perpendicular to the substrate holding surface of the substrate holding table 32 and having a diameter increasing as approaching the substrate holding surface is provided as a new member. As shown in the perspective view of FIG. 3B, the airflow control means 41 has a plurality of cylindrical bodies 41a, 41a,.
It consists of.

Hereinafter, the operation of the CVD apparatus configured as described above will be described. As in the second embodiment, the mist-like droplet 12 sprayed from the sprayer 13 is irradiated with the microwave 18 transmitted from the microwave oscillator 19. Thereby, the vaporized raw material 14 in which the liquid raw material is vaporized is generated above the airflow control means 41.

Here, in general, when an organic metal raw material having a large molecular weight is used, it has a property that it is difficult to diffuse even after being vaporized. Due to this property, it is difficult to obtain a uniform film thickness over the entire surface of the substrate 33 on which a film is to be formed, and when a raw material including a plurality of elements is used, it is difficult to obtain a more uniform composition. .

The vaporized raw material 14 that has been irradiated with the microwave 18 and vaporized has a density distribution in the direction of the substrate holding surface of the substrate holding table 32 according to the injection characteristics of the atomizer 13.
For example, in the case of the atomizer 13 of the present embodiment, the vaporized raw material 1
The density of No. 4 has a distribution that is high near the center of the furnace and decreases as it approaches the side wall. Airflow control means 4
1 is a cylinder 41 according to the spray characteristics of the sprayer 13.
a so that the same amount of vaporized raw material 14 is carried into each of
The width of the gap formed by the inside diameter of each of the cylindrical bodies 41a on the loading side, which is the upper bottom of the truncated cone of the airflow control means 41, is changed. Therefore, on the discharge side, which is the lower bottom portion of the airflow control means 41, the width of the gap formed by the inner diameter of each cylindrical body 41a is made substantially constant.

Thus, on the discharge side of the airflow control means 41, the vaporized raw material 14 can have a uniform density distribution. Further, the influence of the composition deviation due to the diffusion of the vaporized raw material 14 and the reaction gas 34 can be suppressed.

The air flow control means 41 is provided with a heating means (not shown) for circulating heated oil, for example, and is kept at, for example, 200 ° C. so that the vaporized raw material 14 is not reliquefied. ing.

As described above, according to the present embodiment, the vaporized raw material 14 can be supplied at a uniform density to the substrate 33 on which a film is to be formed. In this case, a uniform film thickness and a uniform composition can be obtained.

In the present embodiment, the configuration of the airflow control means 41 is such that the width of the gap formed by the inner diameter of each cylinder 41a is changed on the loading side in accordance with the density distribution.
The discharge side has a substantially constant width. However, if the vaporized raw material 14 can obtain a uniform density on the discharge side, it is obvious that the width on the discharge side can be arbitrarily set.

[0082]

According to the vaporizer of the first aspect of the present invention, a microwave transmitter is provided, and the entire mist droplet can be uniformly heated using the microwave oscillated by the microwave transmitter. Since it is possible to prevent the generation of liquid or solid residues inside the apparatus, the means for removing these residues and the periodic replacement of the vaporizer main body become unnecessary. As a result, a stable vaporized raw material can be generated over a long period of time.

According to the vaporizer according to the second aspect of the present invention,
In addition to obtaining the effect of the vaporizer according to the invention of claim 1,
Since there is provided a heat retaining means for keeping the vaporized raw material at a temperature not lower than the reliquefaction point of the vaporized raw material and not higher than the decomposition point, the generated vaporized raw material does not reliquefy, so that a more stable vaporized raw material is generated. You.

According to the vaporizer according to the third aspect of the present invention,
In addition to obtaining the effect of the vaporizer according to the invention of claim 1,
Since the solvent of the liquid raw material contains polar molecules, the liquid raw material is heated by the generation of molecular vibrations due to microwaves, so that the vaporized raw material can be reliably produced.

According to the vaporizer of the fourth aspect of the present invention,
In addition to obtaining the effect of the vaporizer according to the invention of claim 3,
Since the solvent is an alcohol represented by the general formula ROH (where R is an alkyl group), the solvent is reliably heated by the microwave.

According to the vaporizer according to the fifth aspect of the present invention,
In addition to obtaining the effect of the vaporizer according to the invention of claim 4,
Since the frequency of the microwave is 1 GHz or more and 5 GHz or less, the vibration efficiency is highest with respect to the alcohol of the solvent, and thus the solvent is more reliably heated by the microwave. As a result, a stable vaporized raw material is reliably generated.

According to the vaporizer according to claim 6 of the present invention,
In addition to obtaining the effect of the vaporizer according to the invention of claim 1,
Since the organic metal dissolved in the liquid raw material contains polar molecules, the liquid raw material is surely heated due to the generation of molecular vibrations by microwaves, so that the vaporized raw material can be reliably generated.

According to the vaporizer according to the seventh aspect of the present invention,
In addition to obtaining the effect of the vaporizer according to the invention of claim 6,
The organic metal is represented by the general formula (RO) _n M (where R is an alkyl group,
Since M is represented by a metal element and n is a natural number), the molecular vibration is generated by the microwaves and the material is reliably heated, so that the vaporized raw material can be reliably generated.

According to the vaporizer according to the eighth aspect of the present invention,
In addition to obtaining the effect of the vaporizer according to the invention of claim 6,
The organic metal has the general formula M [I ₃ CCOCHCOCI ₃ ] _n
(However, M is a metal element, n is a natural number, and I is a hydrogen group, an alkyl group, or an electron-withdrawing group). Therefore, molecular vibration is generated by microwaves, and the material is heated without fail. it can.

According to the vaporizer according to the ninth aspect of the present invention,
In addition to obtaining the effect of the vaporizer according to the invention of claim 8,
When the electron-withdrawing group is -NH ₃ , -NR ₃ (where R is an alkyl group; hereinafter the same in this text), -NO ₂ , -C
N, -COOR, -COOH, -CHO, -COR,-
CHCH ₂ , —C ₆ H ₅ , —CCH, —CH ₂ Cl, —O
Since it contains at least one of H, -OR, -F, -Cl, -Br and -CF ₃ , molecular vibrations are generated by microwaves and heating is performed more reliably, so that a vaporized raw material can be reliably generated. become.

According to the tenth aspect of the present invention, since the liquid raw material is vaporized in the reaction furnace, a vaporizer is not required, so that the configuration and control of the apparatus and the maintenance are facilitated.

Further, a microwave oscillator is provided, and the mist-like droplet is heated by using the microwave transmitted from the microwave oscillator, so that the mist-like droplet is uniform regardless of its central part and peripheral part. , The liquid raw material is uniformly vaporized. Accordingly, solid deposition does not occur on the substrate on which the film is to be formed, and a film having good film quality can be formed.

According to the CVD apparatus of the eleventh aspect, the effect of the CVD apparatus of the tenth aspect can be obtained, and the reaction furnace keeps the vaporized raw material warm so as not to reliquefy the vaporized raw material. , The generated vaporized raw material is not reliquefied, so that a more stable vaporized raw material is generated and the film quality of the formed film is improved.

According to the CVD apparatus of the twelfth aspect, the effect of the CVD apparatus of the tenth aspect can be obtained, and the reaction furnace supplies a reaction gas reacting with the vaporized raw material into the reaction furnace. Since the reaction gas supply pipe is provided, a film of, for example, an oxide or a nitride can be formed by selecting and supplying an appropriate reaction gas.

According to the CVD apparatus of the thirteenth aspect, the effect of the CVD apparatus of the twelfth aspect can be obtained, and the reaction gas is O ₂ , NO, N ₂ O and O ₃ . Since at least one is included, a film of an oxide, a nitride, or the like can be reliably formed.

According to the CVD apparatus of the fourteenth aspect, the effect of the CVD apparatus of the tenth aspect is obtained, and the microwave transmitter decomposes a part of the molecules constituting the vaporized raw material. Since the vaporized raw material is irradiated with microwaves, a part of the vaporized raw material is decomposed and reaches the surface of the substrate, so that a film having good crystallinity can be quickly formed at a lower temperature than usual. Thus, even when devices and wirings are formed on the substrate, these devices and the like are not damaged by heat, so that the yield can be improved.

According to the CVD apparatus of the fifteenth aspect, the effect of the CVD apparatus of the tenth aspect can be obtained, and furthermore, the CVD apparatus is provided above the substrate holding table to make the concentration of the vaporized raw material uniform. Is further provided with a gas flow control means, so that a vaporized raw material can be supplied at a uniform density to a substrate on which a film is to be formed, so that a film formed on the substrate has a uniform film thickness in the plane of the substrate. And a uniform composition can be obtained. As a result, a good film can be formed even on a raw material having a high molecular weight.

According to the CVD apparatus of the sixteenth aspect, the effect of the CVD apparatus of the fifteenth aspect can be obtained, and the air flow control means adjusts the center axis perpendicular to the substrate holding surface of the substrate holding table. It has a frusto-conical shape whose diameter increases as approaching the substrate holding surface, and has a plurality of cylinders having different inner diameters and concentric circular cross sections in the radial direction. The concentration of the raw material can be reliably made uniform.

According to the CVD apparatus of the seventeenth aspect, the effect of the CVD apparatus according to the fifteenth or sixteenth aspect can be obtained, and the gas flow control means is provided at a temperature higher than the reliquefaction point of the vaporized raw material and lower than the decomposition point. Since the temperature is kept at the temperature, the generated vaporized raw material does not re-liquefy, so that the concentration of the vaporized raw material with respect to the substrate is more reliably made uniform.

According to the CVD apparatus of the eighteenth aspect, the effect of the CVD apparatus of the tenth aspect can be obtained, and since the solvent of the liquid raw material contains polar molecules, the liquid raw material is a microwave. As a result, molecular vibrations are generated and heating is performed, so that a vaporized raw material can be reliably generated.

According to the CVD apparatus according to the nineteenth aspect, the effect of the CVD apparatus according to the eighteenth aspect is obtained, and the solvent is a compound represented by the general formula ROH (where R is an alkyl group).
Since the alcohol is represented by the formula, the molecular vibration is generated by the microwave and the heating is ensured, so that the vaporized raw material can be reliably generated.

The heating is assured.

According to the CVD apparatus of the twentieth aspect, the effect of the CVD apparatus of the nineteenth aspect can be obtained, and the frequency of the microwave is 1 GHz or more and 5 GHz.
Since it is equal to or less than z, the vibration efficiency is the highest with respect to the alcohol of the solvent, so that the solvent is more reliably heated by the microwave. As a result, a stable vaporized raw material is reliably generated, so that a high-quality film can be formed.

According to the CVD apparatus of the twenty-first aspect, the effect of the CVD apparatus of the tenth aspect is obtained, and the organic metal dissolved in the liquid material contains polar molecules. Since the liquid raw material is heated reliably due to the generation of molecular vibrations by the microwave, the vaporized raw material can be reliably generated.

According to the CVD apparatus of the twenty-second aspect, the effect of the CVD apparatus of the twenty-first aspect is obtained, and the organic metal is represented by the general formula (RO) _n M (where R is an alkyl group, Since M is represented by a metal element and n is a natural number), the molecular vibration is generated by the microwaves and the material is reliably heated, so that the vaporized raw material can be reliably generated.

According to the CVD apparatus of the twenty- _third aspect, the effect of the CVD apparatus of the twenty-first aspect is obtained, and the organic metal is represented by the general formula M [I ₃ CCOCHCOCI.
₃ ] _n (where M is a metal element, n is a natural number, and I is a hydrogen group, an alkyl group, or an electron withdrawing group). Can be generated reliably.

According to the CVD apparatus of the twenty-fourth aspect, the effect of the CVD apparatus of the twenty- _{third aspect} can be obtained, and the electron-withdrawing group can be represented by -NH ₃ , -NR ₃ (where R
Is an alkyl group. The same applies hereinafter in the text. ), - NO _2,
-CN, -COOR, -COOH, -CHO, -CO
_{R, -CHCH 2, -C 6 H} 5, -CCH, -CH 2 C
1, -OH, -OR, -F, -Cl, -Br and -CF
_Since at least one of the three is included, the molecular vibration is generated by the microwave and the heating is performed more reliably, so that the vaporized raw material can be reliably generated.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a configuration of a vaporizer according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view illustrating a configuration of a CVD apparatus according to a second embodiment of the present invention.

FIG. 3 (a) shows a CVD according to a third embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view illustrating a configuration of the device. (B) is a perspective view of the airflow control means of the CVD apparatus according to the third embodiment of the present invention.

FIG. 4 is a cross-sectional view of a configuration of a conventional solution vaporization type CVD apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Case 12 Droplet 13 Atomizer 14 Vaporized raw material 15 Transport gas 16 Transport gas supply pipe 17 Vaporized raw material transport pipe 18 Microwave 19 Microwave oscillator 20 Heating heater 21 Liquid raw material feeder 22 Liquid raw material container 31 Reaction furnace 32 Substrate holding table 33 Substrate 34 Reactive gas 35 Reactive gas supply pipe 36 Reactor heating means 37 Exhaust means 41 Air flow control means 41a Cylindrical body

Claims (24)

[Claims] A liquid material is supplied, an atomizer for converting the supplied liquid material into mist-like droplets, and a microwave is oscillated on the droplets to generate vibrations in molecules constituting the droplets. A vaporizer, comprising: a microwave oscillator that generates a vaporized raw material by heating. 2. The vaporizer according to claim 1, further comprising a heat retaining means for keeping the vaporized raw material at a temperature higher than a reliquefaction point and lower than a decomposition point of the vaporized raw material. 3. The vaporizer according to claim 1, wherein the solvent of the liquid material contains polar molecules. 4. The vaporizer according to claim 3, wherein the solvent is represented by a general formula ROH (where R is an alkyl group). 5. The vaporizer according to claim 4, wherein the frequency of the microwave oscillated by the microwave oscillator is 1 GHz or more and 5 GHz or less. 6. The vaporizer according to claim 1, wherein the organic metal dissolved in the liquid raw material contains a polar molecule. 7. The method according to claim 6, wherein the organic metal is represented by a general formula (RO) _n M (where R is an alkyl group, M is a metal element, and n is a natural number). Vaporizer. 8. The organic metal of the general formula M [I ₃ CCOC
HCOCI ₃ ] _n (where M is a metal element, n is a natural number,
I is a hydrogen group, an alkyl group or an electron withdrawing group. 7. A vaporizer according to claim 6, characterized in that: 9. The method according to claim 9, wherein the electron-withdrawing group is —NH ₃ , —NR ₃
(Wherein, R is an alkyl group.), - NO _2, -C
N, -COOR (where R is an alkyl group),-
COOH, -CHO, -COR (where, R is an alkyl _{group.), - CHCH 2, -C} 6 H 5, -CCH, -C
H ₂ Cl, -OH, -OR (where, R is an alkyl group.), - F, -Cl, to claim 8, characterized in that it comprises at least one of -Br and -CF ₃ A vaporizer as described. 10. A reaction furnace, a substrate holding table provided inside the reaction furnace for holding the substrate and heating the held substrate, and a liquid material formed into mist-like droplets above the substrate holding table. An atomizer for spraying the droplets, oscillating microwaves on the droplets, generating vibrations in molecules constituting the droplets and heating them to generate a vaporized raw material, and supplying the vaporized raw material to the surface of the substrate A CVD apparatus comprising a microwave oscillator. 11. The CVD apparatus according to claim 10, wherein the reaction furnace has a heat retaining means for keeping the vaporized raw material warm so as not to reliquefy the vaporized raw material. 12. The CVD according to claim 10, wherein the reaction furnace has a reaction gas supply pipe for supplying a reaction gas reacting with the vaporized raw material into the reaction furnace.
apparatus. 13. The reaction gas may be O ₂ , NO, N ₂ O.
13. The CVD apparatus according to claim 12, comprising at least one of O ₃ and O ₃ . 14. The CVD apparatus according to claim 10, wherein the microwave transmitter irradiates the vaporized raw material with a microwave for decomposing a part of molecules constituting the vaporized raw material. 15. The C according to claim 10, further comprising an airflow control unit provided above the substrate holding table and configured to make the concentration of the vaporized raw material uniform.
VD device. 16. The airflow controlling means has a central axis perpendicular to the substrate holding surface of the substrate holding table, and has a truncated cone shape whose diameter increases as approaching the substrate holding surface. The CVD apparatus according to claim 15, wherein the CVD apparatus comprises a plurality of cylindrical bodies whose radial cross sections are concentric. 17. The CVD apparatus according to claim 15, wherein said gas flow control means is maintained at a temperature equal to or higher than a reliquefaction point of said vaporized raw material and equal to or lower than a decomposition point. 18. The CVD apparatus according to claim 10, wherein the solvent of the liquid material contains a polar molecule. 19. The CVD apparatus according to claim 18, wherein the solvent is represented by a general formula ROH (where R is an alkyl group). 20. The CVD apparatus according to claim 19, wherein the frequency of the microwave oscillated by the microwave oscillator is 1 GHz or more and 5 GHz or less. 21. The CVD apparatus according to claim 10, wherein the organic metal dissolved in the liquid source contains polar molecules. 22. The method according to claim 21, wherein the organic metal is represented by a general formula (RO) _n M (where R is an alkyl group, M is a metal element, and n is a natural number). CVD equipment. 23. The organometallic compound represented by the general formula M [I ₃ CCO
CHCOCI ₃ ] _n (where M is a metal element, n is a natural number, and I is a hydrogen group, an alkyl group, or an electron withdrawing group)
22. The CV according to claim 21, wherein
D device. 24. The electron withdrawing group is —NH ₃ , —NR
₃ (where R is an alkyl group), -NO ₂ , -C
N, -COOR (where R is an alkyl group),-
COOH, -CHO, -COR (where, R is an alkyl _{group.), - CHCH 2, -C} 6 H 5, -CCH, -C
H ₂ Cl, -OH, -OR (where, R is an alkyl group.), - F, -Cl, to claim 23, characterized in that it comprises at least one of -Br and -CF ₃ The CVD apparatus as described in the above.