JP2000034572A - Apparatus for forming vapor-deposited thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for forming a vapor-deposited thin film capable of controlling the composition of an oxide thin film, making dense the bonding between a metal atom and oxygen atom and lowering growth temp. SOLUTION: The apparatus for forming a vapor-deposited thin film by feeding vaporized liquid metal raw materials to a reaction chamber by a carrier gas and reacting the vapor with a reaction gas to form the vapor-deposited thin film on a substrate, is equipped with a plurality of vaporizers for vaporizing a plurality of liquid metal raw materials, at independent temps., a plurality of transport pipes for transporting vaporized liquid metal raw materials from the vaporizers by a carrier gas, a chamber for reacting the vaporized liquid metal raw materials transported through the transport pipes with a reaction gas to form a deposited film on the substrate, a plasma source for converting the reaction gas into plasma and supplying the plasma to the reaction chamber and a high speed rotary heating mechanism, which is used for forming the deposited film while heating and rotating the substrate at high speed in the reaction chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for producing a vapor-deposited thin film, and more particularly to a chemical vapor deposition (C) method using a liquid organometallic material.
VD: Chemical Vapor Deposit
ion) method and electron cyclotron resonance (ECR: Ele)
ctron Cyclotron Resonance
The present invention relates to a vapor deposition thin film manufacturing apparatus for forming various oxide thin films by combining the methods e).

[0002]

2. Description of the Related Art Recently, a highly integrated DRAM utilizing a high dielectric constant of a ferroelectric material which is a perovskite structure oxide.
Also, non-volatile RAMs utilizing spontaneous polarization characteristics have been actively developed. These perovskite structure oxide thin films are formed by a sol-gel method, a sputtering method,
VD method, etc., but control of composition, step coverage,
The CVD method is the most excellent film forming method in terms of uniformity and the like.

FIG. 5 is a schematic diagram showing an outline of a conventional MOCVD apparatus using the most common liquid metal raw material. Details of such an apparatus are described in, for example, Chemical Engineering, CVD Handbook, pp. 226-227 (published by Asakura Shoten in 1991). In FIG. 5, a and b indicate those relating to different materials. 101 is a dilution gas line such as argon, 102a and 102b are mass flow controllers, 103a and 103b are liquid material containers and bubblers,
4 is a heater, 105 is a source gas transport tube, 106 is a reaction chamber, 107 is a heating mechanism, 108 is a substrate, 109 is a reactive gas transport tube, 110 is an exhaust system, and 111 is a detoxification line.

Next, the operation will be described. Heater 1
04, the bubblers 103a, 103b containing the liquid raw materials are heated to a desired temperature.
Diluent gas whose flow rate is controlled from a and b is bubbler 103
a and b are respectively supplied to the bubblers 103a and 103b.
By bubbling in the liquid raw material inside, a part of the liquid raw material is vaporized, and the raw material gas corresponding to the saturated vapor pressure at a desired temperature is mixed with the diluent gas in the raw material gas transport pipe 105.
Is supplied to the reaction chamber 106 via the The source gas supplied to the reaction chamber 106 reacts on the surface of the substrate 108 heated by the heating mechanism 107 with an oxidizing agent such as oxygen supplied from the reaction gas transport pipe 109 to deposit a thin film on the substrate 108. The liquid raw material and the reaction gas that do not contribute to the deposition are exhausted to the abatement line 111 through the exhaust system 110.

[0005]

In a conventional CVD apparatus for producing an oxide, a liquid material is formed in the same temperature control mechanism as described above, and a reactive gas is supplied simultaneously with the material. Although oxygen gas has been used, when an oxide is formed by such a method, a metal atom and an oxygen atom that are decomposed only by heat energy on a substrate surface are bonded to form an oxide.

However, there is a problem in that the oxygen gas alone has a weak oxidizing power, so that oxygen deficiency in the crystal is generated to deteriorate the characteristics of the thin film. In addition, in order to uniformly form a thin film on a substrate, there is a problem in that it is difficult to design a nozzle for supplying a raw material, and it is not possible to form an oxide thin film uniformly.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems of the prior art, and can control the composition of an oxide thin film so that the bonding between metal atoms and oxygen atoms becomes dense. It is an object of the present invention to provide an apparatus for producing a vapor-deposited thin film capable of lowering the growth temperature.

[0008]

That is, the present invention relates to a vapor deposition thin film producing apparatus for supplying a vaporized liquid metal raw material to a reaction chamber with a carrier gas and reacting with the reaction gas to form a film on a substrate. A plurality of vaporizers for vaporizing the liquid metal raw material at independent temperatures, a plurality of transport pipes for transporting the liquid metal raw material vaporized by the carrier gas from the plurality of vaporizers, and transport by the plurality of transport pipes A reaction chamber for reacting the vaporized liquid metal raw material with a reaction gas to form a film on a substrate, a plasma source for converting the reaction gas into plasma and supplying the reaction chamber to the reaction chamber, and heating the substrate in the reaction chamber at a high speed An evaporated thin film manufacturing apparatus characterized by having a heating high-speed rotation mechanism for forming a film while rotating.

Preferably, the vaporizer has a pore block having a pore diameter of 10 μm or less in order to vaporize the liquid raw material. It is preferable that the plasma source generates a plasma of a reaction gas by electron cyclotron resonance.
It is preferable that the plasma source supplies a reactive plasma gas to the substrate by a divergent magnetic field generated by a magnetic coil necessary for generating plasma by electron cyclotron resonance.

The number of rotations of the heating high-speed rotation mechanism is 500 to
It is preferably in the range of 2000 rpm. It is preferable that the tips of the individual transport pipes for transporting the liquid metal raw material vaporized by the carrier gas from the plurality of vaporizers to the reaction chamber are arranged in a row in the radial direction near the substrate.

It is preferable that a three-way valve is provided on the raw material supply side of the vaporizer to control the supply of the liquid metal raw material to the vaporizer so that the composition can be continuously sharply changed. A three-way valve is provided on the side that supplies the liquid metal raw material, one is connected to the liquid metal raw material, and the other is connected to a solvent tank containing only the solvent that liquefies the metal raw material, and the solvent is supplied to the vaporizer side. Preferably, it can be flowed.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An apparatus for producing a vapor-deposited thin film according to the present invention is an apparatus for producing a vapor-deposited thin film, wherein a vaporized liquid metal material is supplied to a reaction chamber by a carrier gas and reacted with the reaction gas to form a film on a substrate. A plurality of vaporizers for vaporizing the plurality of liquid metal raw materials at independent temperatures, a plurality of transport pipes for transporting the liquid metal raw material vaporized by the carrier gas from the plurality of vaporizers, and the plurality of transport pipes A reaction chamber for reacting the transported vaporized liquid metal raw material with a reaction gas to form a film on a substrate, a plasma source for converting the reaction gas into a plasma to be supplied to the reaction chamber, and heating the substrate in the reaction chamber It has a heating high-speed rotation mechanism for forming a film while rotating at high speed.

As described above, in the apparatus for producing a vapor-deposited thin film according to the present invention, the vaporizer has a separate structure, and the vaporization is performed at a temperature suitable for each liquid metal raw material. Since the raw material concentration can be kept constant since the liquid metal raw materials do not mix with each other and there is no deterioration, a thin film having a strict composition can be formed.

Also, by using a pore block inside the vaporizer to vaporize the liquid metal raw material, clogging of the raw material piping system can be prevented, and efficient vaporization with less residue inside the vaporizer can be realized. Become. Since the vaporized source gas is supplied onto the substrate by a separate gas nozzle, there is no precipitation due to a temperature difference inside the conventional vaporizer, and the gas nozzle is arranged in the radial vector direction with respect to the rotation direction of the substrate, and By rotating the substrate at a high speed, the distribution of the source gas on the substrate can be made uniform.

In addition, since the reaction gas is converted into plasma by electron cyclotron resonance (ECR) and the gas plasma is supplied to the substrate with the flow of a magnetic field, the substrate is not etched by the plasma, and the oxidation efficiency can be increased as compared with the prior art, so that good quality can be obtained. Thus, a dense oxide thin film can be formed at a low temperature. ECR
Is used, several mTorr to 10 ^-4 or 10 ^-5 T
Since plasma can be generated in the range of orr, the film formation rate can be controlled even by the degree of vacuum in the reaction chamber.

Further, by providing a three-way valve immediately before the vaporizer to change the supply of the liquid metal raw material to the vaporizer to the raw material storage container, the liquid to be supplied to the vaporizer when a multilayer thin film is produced. Thin films having different compositions can be produced without giving a change in the supply pressure of the metal raw material, and a thin film having a sharp composition change can be produced. In addition, the film forming speed can be stably controlled during the film forming. Further, since a liquid metal raw material can be recovered, a film forming apparatus with high raw material efficiency can be obtained.

A three-way valve is provided between the liquid mass flow controller and the liquid metal raw material container, and one of the valves is connected to the raw material container and the other is connected to the solvent tank, so that the inside of the liquid mass flow controller and the raw material can be formed after film formation. The supply line and the inside of the vaporizer can be washed with the solvent, and the solidification of the raw material in the line, the vaporizer, and the nozzle due to the residual raw material can be prevented by flushing the remaining liquid metal raw material.

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples.

Embodiment 1 Next, an embodiment according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing the structure of an embodiment of the apparatus for producing a deposited thin film of the present invention. Although only one system is shown in FIG. 1 for supplying raw materials, the subscripts a, b, and c in the figure indicate that there are separate raw material supplies. 1 is a gas line for pressurizing the liquid metal material container 2, 3 is a liquid mass flow controller, 4 (4a, b, c) is a liquid material supply line, 5a,
b and c correspond to different liquid source vaporizers. 6a,
b and c are mass flow controllers for supplying carrier gas,
Reference numeral 7 denotes a carrier gas, and reference numerals 8a, b, and c denote gas nozzles from separate vaporizers, which are arranged at positions parallel to each other in the radial direction of the substrate 11. 9 is a reaction chamber, 11 is a mechanism for heating and rotating the substrate 10 at high speed, 12 is a variable valve or pressure controller for adjusting the pressure of the reaction chamber,
13 is a TMP (turbo molecular pump) and 14 is an auxiliary pump. Reference numeral 15 denotes a plasma chamber for producing plasma, 16 denotes a magnetic coil for causing cyclotron resonance, 17 denotes a microwave generator, and 18 denotes a microwave waveguide. 19 is a mass flow controller for a reaction gas,
20 is a reaction gas line. Reference numeral 21 denotes a heater for heating the vaporizer 5 to a constant temperature by a temperature detection sensor (not shown). Incidentally, reference numerals 31 to 41 indicate valves.

Next, the operation will be described.

The vaporizer 5 is heated to 220 ° C. by the heater 21.
After setting the temperature to about the temperature and heating, the valve 32 is opened to pressurize the liquid raw material container 2. The liquid metal raw material extruded from the container is supplied to the liquid mass flow controller 3 through valves 33, 35, and 37. The flow rate of the liquid mass flow controller 3 is set to 1 sccm, and the liquid metal source controlled to 1 sccm is sent to the vaporizer 5 a through the liquid source line 4.

The inside of the vaporizer 5a has a structure as shown in FIG. 2, and the pressurized liquid raw material 209 is supplied from the nozzle 201 through the connection part 205 to the supply line 4 from the nozzle 201.
It is sprayed on 2. Since the pore block 202 is heated by the external heater 21, the pore block 20
The liquid raw material 209 in contact with 2 evaporates instantaneously. Since the inside of the mixing chamber 204 is depressurized by the reaction chamber 9, the vaporized liquid metal raw material is drawn into the mixing chamber 204 through the pore block 202. With such a configuration of the vaporizer, the internal pore block can instantaneously vaporize the liquid metal raw material, and liquid or particulate components are not transported to the reaction chamber. The vaporized liquid metal raw material is mixed with the carrier gas 208 controlled at 100 sccm by the carrier gas mass flow 6a in the mixing chamber 204, and is conveyed to the gas nozzle 8a in the reaction chamber 9 as the vaporized gas 210. The vaporized gas 210 is blown onto the surface of the substrate 11 via the gas nozzle 8a as shown in FIG.

On the other hand, oxygen plasma as a reaction gas is generated by electron cyclotron resonance. This is described in the reference: S.M. Matsuo and Y. Adachi: J
pn. J. Appl. Phys. , 21, L4 (198
It is described in detail in 2). In this embodiment, the reaction gas 2
Oxygen gas was set to 0 and gas mass flow 19 was 30 sccm.
Then, the flow rate was set in the plasma chamber 15 and the degree of vacuum in the reaction chamber 9 was controlled to 0.01 Torr by the pressure control valve 12.

Next, a microwave oscillator (oscillation frequency;
(2.45 GHz) 17 is set to 100 W and a microwave is oscillated and guided to the plasma chamber 15 via the waveguide 18. The microwave guided by the waveguide 18 is applied to a magnetic coil 16 in a quartz plasma chamber 15 serving as a cavity resonator.
875 Gauss is applied to generate electron cyclotron resonance to generate oxygen plasma. The generated oxygen plasma is applied to the substrate 10 by the divergent magnetic field of the magnetic coil 16. Thus, the substrate 10 is irradiated with the vaporized gas 210 and the oxygen plasma. At this time, the substrate 1
0 is heated to 550 ° C. by the heating and rotating mechanism 11 and is rotated at 1000 rpm, so that the raw material forms a laminar flow on the substrate and an oxide thin film having a uniform composition is formed on the surface of the substrate 10.

Embodiment 2 A second embodiment of the present invention will be described with reference to FIG.
The description of the same parts as in the first embodiment will be omitted. This is provided with a three-way valve 47 in the raw material line 4 between the vaporizer 5 and the liquid mass flow controller 3.

The valve 42 is connected to the raw material line 4 and the valve 43 is connected to the vaporizer 5 among the three-way valves. Then, the remaining valve 44 is connected to the liquid container 48. As an operation, when forming a film using this liquid metal raw material line 4, the valve 44 is closed and the valves 42 and 43 are opened to supply the liquid metal raw material to the vaporizer 5a. When it is desired to rapidly change the composition of another liquid metal material or the same liquid metal material during the formation of a multilayer thin film, the valve 43 is closed and the valve 44 and the valves 45 and 46 of the container 48 are simultaneously opened to open the liquid metal material. Is collected in the storage container 48. When a thin film is formed using the liquid metal raw material 2 again, the valve 44 is closed and the valve 43 is opened so that the liquid metal raw material can be smoothly transported to the vaporizer 5a.

As a result, it is possible to switch the raw material without changing the supply pressure to the vaporizer, and it is easy to form a thin film in which a different material is formed or the composition is sharply changed when a multilayer thin film is formed.

Embodiment 3 A third embodiment of the present invention will be described with reference to FIG.
The description of the same parts as in the first embodiment will be omitted. During normal film formation, the valve 54 on the solvent container 52 is closed, and the liquid metal raw material is supplied to the vaporizer 5 via the valve 37 via the liquid mass flow controller 3 and the three-way valve 47.

After the film formation is completed, the valves 32, 33 and 35 are opened and the valve 3 of the liquid mass flow controller 3 is opened.
7, the valve 31 for pressurizing the liquid source container 2 is then closed, and the valve 34 is gradually opened to return the pressure in the source container to atmospheric pressure. In this way, the liquid metal raw material filled up to the valve 37 returns to the raw material container 2. When the pressure of the raw material container reaches the atmospheric pressure, the valves 32, 34 and 35 are closed, and the valves 53, 54 and 55 of the solvent container 52 are opened to pressurize the solvent container 52. At this time, the liquid mass flow controller 3 is fully opened and the valves 42, 44, 45, 46 are opened so that the solvent is supplied to the liquid mass flow controller 3 and the supply line 4.
The liquid metal raw material in the inside is flushed through the three-way valve 47, so that the liquid mass flow controller 3, the supply line 4, and the three-way valve 47 can be cleaned.

After the substrate 10 is taken out of the reaction chamber 9, the valve 44 is closed, the valve 43 is opened, and the solvent flows into the vaporizer 5, so that the vaporizer and the gas nozzle 8 can also be cleaned. By flowing such a solvent, it is possible to remove a liquid metal raw material that is likely to deteriorate and solidify with the passage of time and to cause clogging of a gas line, a vaporizer, a nozzle, and the like.

[0031]

As is clear from the above description, in the apparatus for producing a vapor-deposited thin film according to the present invention, the composition can be strictly controlled by providing a vaporizer for each constituent atom. Also, by using oxygen plasma as compared with the case where oxygen gas or ozone is used as the reaction gas, the bond between the thermally decomposed constituent atoms and the oxygen atoms becomes denser, and the growth temperature can be lowered. Further, it was effective in replenishing oxygen to the thin film during vapor phase growth and effective in improving the thin film structure.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the structure of an embodiment of the apparatus for producing a deposited thin film of the present invention.

FIG. 2 is an explanatory diagram showing the inside of a vaporizer used in the present invention.

FIG. 3 is a schematic view showing the structure of another embodiment of the apparatus for producing a deposited thin film of the present invention.

FIG. 4 is a schematic view showing the structure of another embodiment of the apparatus for producing a deposited thin film of the present invention.

FIG. 5 is a schematic view showing the structure of a conventional CVD apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 51 Gas line 2 Liquid metal raw material container 3 Liquid mass flow controller 4 Liquid metal raw material supply line 5a, b, c Vaporizer 6 Mass flow controller for carrier gas 7, 208 Carrier gas 8a, b, c Gas nozzle 9, 106 Reaction chamber 10 , 108 substrate 11 heating rotation mechanism 12 pressure control valve 13 TMP 14 auxiliary pump 15 plasma chamber 16 magnetic coil 17 microwave oscillator 18 waveguide 19 reaction gas mass flow controller 20 reaction gas line 21, 104 heating heater 31-41, 42 -46, 53-55 Valve 47 Three-way valve 48 Liquid storage container 51 Pressurization line 52 Solvent container 101 Dilution gas line 102 Mass flow controller 103 Liquid metal raw material container and bubbler 105 Raw material gas supply pipe 10 Heating mechanism 109 Reaction gas transport pipe 110 Exhaust system 111 Abatement line 201 Nozzle 202 Pore block 203 Block holder 204 Mixing chamber 205 Liquid raw material line connection 206 Carrier gas line connection 207 Vaporized gas line connection 209 Liquid metal raw material 210 Vaporization gas

Claims (8)

[Claims] In a vapor deposition thin film producing apparatus for supplying a vaporized liquid metal raw material to a reaction chamber by a carrier gas and reacting with the reaction gas to form a film on a substrate, a plurality of liquid metal raw materials are vaporized at independent temperatures. A plurality of vaporizers, a plurality of transport pipes for transporting the liquid metal raw material vaporized by the carrier gas from the plurality of vaporizers, and a reaction between the vaporized liquid metal raw material transported by the plurality of transport pipes. A reaction chamber for reacting with a gas to form a film on a substrate, a plasma source for supplying a reaction gas to the reaction chamber in the form of plasma, and a heating high-speed rotating mechanism for heating and rotating the substrate in the reaction chamber to form a film An apparatus for producing a vapor-deposited thin film, comprising: 2. The apparatus according to claim 1, wherein the vaporizer has a pore block having a pore diameter of 10 μm or less for vaporizing a liquid raw material. 3. The apparatus according to claim 1, wherein the plasma source generates plasma of a reaction gas by electron cyclotron resonance. 4. The apparatus according to claim 1, wherein the plasma source supplies a reactive plasma gas to the substrate by a divergent magnetic field generated by a magnetic coil necessary for generating plasma by electron cyclotron resonance. 5. The rotation speed of the heating high-speed rotation mechanism is 500.
2. The apparatus for producing a vapor-deposited thin film according to claim 1, wherein the thickness is in the range of 2,000 rpm. 6. The tip of each transport pipe for transporting a liquid metal raw material vaporized by a carrier gas from the plurality of vaporizers to a reaction chamber is arranged in a row in a radial direction near a substrate. The apparatus for producing a vapor-deposited thin film according to the above. 7. An apparatus for producing a vapor-deposited thin film according to claim 1, wherein a three-way valve is provided on the raw material supply side of the vaporizer to control the supply of the liquid metal raw material to the vaporizer so that the composition can be continuously sharply changed. . 8. A three-way valve is provided on the side for supplying the liquid metal raw material, one of which is connected to a liquid metal raw material and the other is connected to a solvent tank containing only a solvent for liquefying the metal raw material for vaporization. The apparatus for producing a vapor-deposited thin film according to claim 1, wherein the solvent can be flowed to the vessel side.