Supply method and supply device

Abstract

To continuously supply a high-concentration gaseous material with a simple device without the need of heating the material to high temperature.SOLUTION: A method for supplying a gaseous material includes: a mixture gas preparation step of introducing a carrier gas into a container in which the material is stored in a solid or liquid state to obtain a mixture gas of the gaseous material and the carrier gas; a concentration step of obtaining a concentrated gas of which concentration of the material in the mixture gas is increased using a separation membrane; and a supply step of supplying the concentrated gas to a device that uses the material.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a supply method for supplying a gaseous material. Further, the present invention relates to a supply device for supplying a gaseous material.

Background Art

[0002] Techniques for film formation, etching, etc. using gaseous materials are used in various fields.

[0003] For example, in the manufacture of semiconductor devices, processes for forming thin films such as metals, metal oxides, and metal nitrides are generally used. In particular, in recent years, in order to cope with the miniaturization and high integration of semiconductor devices, film thickness control on the sub-nm order is possible, and a thin film formation technique having good coverage characteristics is required.

[0004] As film formation processes that can meet such requirements, film formation methods such as chemical vapor deposition (CVD) and atomic layer deposition (ALD) are generally used. In these film formation methods, various materials such as metal-containing compounds, nitrogen-containing compounds, oxidation-containing compounds, and carbon-containing compounds are used as film formation raw materials. However, since many of these materials are in a liquid or solid state under normal conditions, they need to be supplied to the film formation apparatus in a gaseous state for use in the above film formation methods.

[0005] Similarly, in processes other than film formation (for example, dry etching, etc.), it is generally performed to supply a gaseous material.

[0006] As a method for supplying a material to a film formation apparatus in a gaseous state, a method of vaporizing the material and supplying it together with a carrier gas is widely used. Specifically, first, a carrier gas is introduced into a container in which the material is stored in a solid or liquid state to obtain a mixed gas of the vaporized material and the carrier gas. Next, the mixed gas is supplied to the film formation apparatus.

[0007] According to the above method, a gaseous material can be stably supplied to a film forming apparatus. However, this method has a problem that the concentration of the material contained in the mixed gas is low.

[0008] That is, in order to form a high-quality thin film in the film forming process, it is necessary to increase the concentration of the supplied material gas. Also, in processes other than film formation, such as dry etching, in order to efficiently proceed with the reaction, an increase in the concentration of the material gas is required.

[0009] However, in the above supply method, since the material is supplied in a state diluted by the carrier gas, the concentration of the material gas is low. In addition, since many of the materials used in this supply method have a low vapor pressure, it is difficult to increase the material concentration in the mixed gas.

[0010] As a method for increasing the material concentration in the mixed gas, it is conceivable to heat a solid or liquid material to a high temperature. If heated to a high temperature, the amount of the material that vaporizes increases, so that the material concentration in the mixed gas becomes high. However, since many of the materials used in these applications are easily decomposed by heat, there is a limit to increasing the concentration by heating.

[0011] Therefore, in Patent Documents 1 and 2, a technique has been proposed in which a material gas is adsorbed on a porous metal complex and then desorbed by heating to concentrate the material gas.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0013] According to the methods proposed in Patent Documents 1 and 2, the concentration of the material gas can be increased. However, in the above method, since it is necessary to alternately perform two steps of adsorbing the material gas to the porous metal complex and then desorbing it by heating, the material can be supplied only intermittently. In order to continuously supply the material by the above method, at least two supply lines equipped with adsorption towers filled with the porous metal complex need to be prepared and operated while switching the supply lines. Therefore, the system becomes complicated and the apparatus becomes large-sized.

[0014] The present invention has been made to solve the above problems, and an object thereof is to continuously supply a high-concentration gaseous material with a simple apparatus without the need to heat the material to a high temperature.

Means for Solving the Problems

[0015] The present inventors have made the present invention to achieve the above problems, and the gist thereof is as follows.

[0016] 1. A supply method for supplying a gaseous material, comprising: a mixed gas preparation step of introducing a carrier gas into a container containing the material in a solid or liquid state to obtain a mixed gas of the vaporized material and the carrier gas; a concentration step of using a separation membrane to obtain a concentrated gas with an increased concentration of the material in the mixed gas; and a supply step of supplying the concentrated gas to an apparatus using the material.

[0017] 2. The supply method according to 1 above, wherein the separation membrane has pores with an average diameter of 0.1 to 10 nm.

[0018] 3. The supply method according to 1 or 2 above, wherein in the concentration step, a double-tube separator equipped with the separation membrane is used.

[0019] 4. The supply method according to any one of 1 to 3 above, wherein in the concentration step, one side of the separation membrane is depressurized.

[0020] 5. The supply method according to any one of 1 to 4 above, wherein the material is at least one selected from the group consisting of aluminum chloride, hafnium chloride, zirconium chloride, tantalum chloride, tungsten pentachloride, tungsten hexachloride, molybdenum dichloride dioxide, molybdenum pentachloride, ruthenium chloride, hydrazine compounds, hafnium compounds, zirconium compounds, platinum compounds, ruthenium compounds, cobalt compounds, silicon compounds, aluminum compounds, titanium compounds, tantalum compounds, pure water, hydrogen peroxide, and organic solvents.

[0021] 6. A supply device for supplying a gaseous material, a container in which the material is accommodated in a solid or liquid state, a carrier gas flow path for introducing a carrier gas into the container, a mixed gas flow path for taking out a mixed gas of the vaporized material and the carrier gas from the container, a concentrating means for obtaining a concentrated gas with an increased concentration of the material in the mixed gas by using a separation membrane, and a concentrated gas flow path for supplying the concentrated gas to a device using the material.

[0022] 7. The supply device according to 6 above, wherein the separation membrane has pores with an average diameter of 0.1 to 10 nm.

[0023] 8. The supply device according to 6 or 7 above, wherein the concentrating means is a double-tube separator including the separation membrane.

[0024] 9. The supply device according to any one of 6 to 8 above, further comprising a pressure reducing means for reducing the pressure on one side of the separation membrane.

[0025] 10. The supply device according to any one of 6 to 9 above, wherein the material is at least one selected from the group consisting of aluminum chloride, hafnium chloride, zirconium chloride, tantalum chloride, tungsten pentachloride, tungsten hexachloride, molybdenum dichloride dioxide, molybdenum pentachloride, ruthenium chloride, hydrazine compounds, hafnium compounds, zirconium compounds, platinum compounds, ruthenium compounds, cobalt compounds, silicon compounds, aluminum compounds, titanium compounds, tantalum compounds, pure water, hydrogen peroxide, and organic solvents.

Advantages of the Invention

[0026] According to the present invention, unlike the prior art proposed in Patent Documents 1 and 2, since concentration is performed using a separation membrane, despite being a simple device, a high-concentration gaseous material can be continuously supplied in-line. In addition, since a high-concentration gas can be supplied without heating the material to a high temperature when vaporizing it, it can be used for supplying a wide range of materials.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0028] Next, a method for implementing the present invention will be specifically described. Note that the following description shows examples of preferred embodiments of the present invention, and the present invention is not limited by the following description in any way. In this specification, when the concentration of a component in a gas is expressed as “%”, it represents “volume %” unless otherwise specified.

[0029] Figure 1 is a schematic diagram of a supply device 1 according to an embodiment of the present invention. The supply device 1 includes a carrier gas flow path 10, and carrier gas is introduced into the container 20 through the carrier gas flow path 10. It is preferable that a flow rate adjusting means 11 for adjusting the flow rate of the carrier gas is provided in the carrier gas flow path 10. As the flow rate adjusting means 11, for example, one or both of a needle valve and a mass flow controller can be used. Further, the carrier gas flow path 10 can be provided with a valve capable of opening and closing the flow of the carrier gas. In the example shown in FIG. 1, the carrier gas flow path 10 is provided with two valves 12 and 13.

[0030] The container 20 is a container for storing the material M. The material M is stored in the container 20 in a solid or liquid state. When carrier gas is introduced from the carrier gas flow path 10 into the container 20, the vaporized material M and the carrier gas are mixed to form a mixed gas (mixed gas preparation step).

[0031] The container 20 preferably includes heating means (not shown) for heating the material M contained in the container 20. As the heating means, any material can be used without particular limitation. As the heating means, for example, at least one selected from the group consisting of a mantle heater, a ribbon heater, a silicone rubber heater, an aluminum heater, a thermostatic bath, a water bath, and an oil bath is preferably used. Further, the heating means preferably includes a temperature control device for keeping the temperature of the material M constant.

[0032] A mixed gas flow path 30 for taking out the mixed gas is connected to the container 20, and the mixed gas is sent to the concentration means 40 through the mixed gas flow path 30. The mixed gas flow path can be provided with a valve capable of opening and closing the flow of the mixed gas. In the example shown in FIG. 1, the mixed gas flow path 30 is provided with two valves 31 and 32.

[0033] As shown in FIG. 1, it is preferable to provide a bypass channel 14 connecting a carrier gas channel 10 and a mixed gas channel 30, and a valve 15 for opening and closing the bypass channel 14. By providing the bypass channel 14 in this way, the carrier gas can flow downstream without passing through the container 20, so that maintenance of the supply device such as flushing can be easily performed. In particular, when the pipe is opened while gas remains in the channel, the released gas may react with components in the atmosphere to generate toxic gas. However, if there is a bypass channel 14, the residual gas can be purged in advance, so that the work can be carried out safely.

[0034] Also, it is preferable that the mixed gas channel 30 is provided with pressure measuring means 33. By using the pressure measuring means 33, the pressure of the mixed gas can be monitored. Furthermore, it is preferable that the mixed gas channel 30 is provided with pressure adjusting means 34. By controlling the pressure adjusting means 34 based on the pressure measured by the pressure measuring means 33, the pressure of the mixed gas can be adjusted. As the pressure adjusting means 34, for example, a back pressure valve (back pressure regulator, BPR), an auto pressure regulator, a piezo valve, a pressure control system, etc. can be preferably used.

[0035] Also, the pressure measuring means 33 can be used to detect the occurrence of an abnormality inside the container. For example, when an abnormal pressure increase occurs due to thermal decomposition of the material or the like, it can be detected by the pressure measuring means 33. When such an abnormality is detected, for example, the abnormal pressure increase can be removed from the vacuum exhaust line.

[0036] The concentration means 40 includes a separation membrane (not shown), and a concentrated gas with an increased concentration of the material in the mixed gas can be obtained by the separation membrane (concentration step). The preferred form of the concentration means 40 will be described later.

[0037] In addition, if the temperature of the gas drops excessively during the concentration process, the material gas contained in the gas may liquefy or solidify inside the flow path or the concentration means 40. Therefore, it is preferable that the concentration means 40 further includes a heating means (not shown). It is more preferable that the heating means includes a temperature control means for maintaining the temperature at a predetermined temperature.

[0038] A concentrated gas flow path 50 is connected to the downstream side of the concentration means 40, and the concentrated gas is supplied to the apparatus 60 through the concentrated gas flow path 50 (supply process). It is preferable that the concentrated gas flow path 50 is provided with a valve 51 capable of opening and closing the flow of the concentrated gas.

[0039] The type of the apparatus 60 is not particularly limited, and any apparatus may be used as long as it uses the above material. Representative apparatuses include a film forming apparatus and a dry etching apparatus. Examples of the film forming apparatus include a CVD apparatus and an ALD apparatus.

[0040] On the other hand, it is preferable that an exhaust flow path 70 is connected to the downstream side of the concentration means 40. In the concentration means 40, a concentrated gas is obtained by selectively permeating the carrier gas through the separation membrane. At this time, a gas with a reduced concentration of the concentrated gas is generated simultaneously. Therefore, the gas with a reduced concentration of the concentrated gas may be discharged through the exhaust flow path 70.

[0041] As shown in FIG. 1, it is preferable that a pressure reducing means 71 is connected to the exhaust flow path 70. By the pressure reducing means, one side (exhaust side) of the separation membrane of the concentration means 40 can be depressurized, and the carrier gas can be effectively separated. The pressure reducing means 71 is not particularly limited, and any one can be used. Typically, a vacuum pump is used. As the vacuum pump, for example, at least one selected from the group consisting of a dry pump, a scroll pump, an oil rotary pump, a turbo molecular pump, a diaphragm pump, and a cryopump can be used.

[0042] In addition, the exhaust passage 70 preferably includes a valve 72 that can open and close the flow of the gas to be exhausted.

[0043] According to the present invention, different from the prior art, since concentration is performed using a separation membrane, despite being a simple device, a high-concentration gaseous material can be continuously supplied in-line. Further, since concentration is performed by the separation membrane, it is not necessary to heat the material to a high temperature to increase the concentration when vaporizing it. Therefore, the present invention can be used for the supply of a wide range of materials.

[0044] (Material) The present invention can be used for the supply of any material without particular limitation. The material is accommodated in a container in a solid or liquid state. Therefore, usually, it is preferable to use a material that is solid or liquid at normal temperature and normal pressure. Further, the material needs to finally become gaseous and be supplied to the apparatus. Therefore, the material is preferably volatile or sublimable.

[0045] In one embodiment of the present invention, the material is at least one selected from the group consisting of aluminum chloride, hafnium chloride, zirconium chloride, tantalum chloride, tungsten pentachloride, tungsten hexachloride, molybdenum dichloride dioxide, molybdenum pentachloride, ruthenium chloride, hydrazine compounds, hafnium compounds, zirconium compounds, platinum compounds, ruthenium compounds, cobalt compounds, silicon compounds, aluminum compounds, titanium compounds, tantalum compounds, pure water, hydrogen peroxide, and organic solvents.

[0046] In the present invention, a plurality of materials can also be supplied simultaneously. When supplying a plurality of materials, for example, a plurality of materials may be accommodated in a mixed state in one container, and these plurality of materials may be vaporized and supplied simultaneously. Alternatively, a plurality of containers each containing a different material may be used. When using a plurality of containers, a carrier gas may be supplied to each container, and the mixed gas from each container may be supplied to one concentration apparatus.

[0047] (Carrier gas) Regarding the carrier gas as well, any gas can be used without particular limitation. Examples of the carrier gas include helium (He), argon (Ar), nitrogen (N 2 ), and at least one selected from the group consisting of hydrogen (H 2 ) is preferably used. From the viewpoint of ease of concentration by the separation membrane, it is more preferable to use argon or helium, which are monatomic molecules, as the carrier gas.

[0048] (Concentration means) Next, the concentration means will be described in more detail. As described above, the concentration means of the present invention includes a separation membrane. Usually, the molecular sizes of the material and the carrier gas are different, and generally, the carrier gas molecules are smaller in size than the molecules of the material. Due to this difference in molecular size, the separation membrane can selectively permeate the carrier gas.

[0049] The separation membrane to be used is not particularly limited, but it is preferable to use a separation membrane having pores with an average diameter of 0.1 to 10 nm.

[0050] Also, the material of the separation membrane is not particularly limited, and for example, a separation membrane made of at least one selected from silica, carbon, zeolite, and resin can be used.

[0051] From the viewpoint of increasing the concentration of the material gas finally supplied to a film-forming apparatus or the like, it is desirable to remove the carrier gas in the mixed gas as much as possible in the concentration step using the separation membrane. From this viewpoint, it is preferable to remove 1% or more of the carrier gas contained in the mixed gas, preferably 10% or more, and more preferably 50% or more. On the other hand, the upper limit of the ratio of the carrier gas to be removed is not particularly limited and may be 100%, but may also be 99% or less.

[0052] The structure of the concentration means is not particularly limited. Typically, a mixed gas may be supplied to one side (concentration side) of the separation membrane, and the carrier gas contained in the mixed gas may be selectively permeated to the other side (permeation side) of the separation membrane. By permeating the carrier gas in this way, the concentration of the material gas in the mixed gas supplied to the one side can be increased to obtain a concentrated gas. When performing decompression, the permeation side of the separation membrane may be decompressed.

[0053] The number of the concentration means is not particularly limited, and it may be one or a plurality. When using a plurality of concentration means, they may be connected in parallel or directly connected.

[0054] (Double-tube separator) In one embodiment of the present invention, it is preferable to use a double-tube separator as the concentration means. Hereinafter, the case of using a double-tube separator will be described.

[0055] FIG. 2 is a schematic view showing the structure of a double-tube separator 100 in one embodiment of the present invention. The double-tube separator 100 includes an outer tube 110 and an inner tube 120 provided so as to pass through the inside of the outer tube 110. At least a part of the wall surface of the inner tube 120 is constituted by a separation membrane 121.

[0056] The mixed gas is first supplied into the outer tube 110 as shown by arrow a. Then, at least a part of the carrier gas contained in the mixed gas permeates through the separation membrane 121 and enters the inside of the inner tube 120 (arrow b). As a result, the concentration of the material gas in the supplied mixed gas increases to become a concentrated gas. The obtained concentrated gas is discharged from the outer tube 110 as shown by arrow c. On the other hand, the carrier gas that has permeated through the separation membrane 121 is discharged from the inner tube 120 as shown by arrow d.

[0057] (Temperature) As described above, the container preferably includes heating means for heating the material contained in the container. The temperature for heating the material in the container is not particularly limited as long as the material does not decompose. From the viewpoint of promoting vaporization of the material contained in the container, it is preferable to heat the container to 30°C or higher. On the other hand, if heated excessively, the material may undergo thermal decomposition. Therefore, in one embodiment of the present invention, it is preferable that the heating temperature when heating the container is equal to or lower than the decomposition temperature of the material, and more preferably (decomposition temperature - 20°C) or lower. Further, in another embodiment of the present invention, it is preferable that the heating temperature when heating the container is 200°C or lower.

[0058] Also, as described above, the concentration means preferably includes heating means to prevent liquefaction and solidification of the material. The temperature for heating the concentration means is not particularly limited as long as the material does not decompose. From the viewpoint of preventing liquefaction and solidification of the material, it is preferable to heat the concentration means to 30°C or higher. On the other hand, if heated excessively, the material may undergo thermal decomposition. Therefore, in one embodiment of the present invention, it is preferable that the heating temperature when heating the concentration means is equal to or lower than the decomposition temperature of the material, and more preferably (decomposition temperature - 20°C) or lower. Further, in another embodiment of the present invention, it is preferable that the heating temperature when heating the concentration means is 250°C or lower.

[0059] When heating both the material in the container and the concentration means, it is preferable that the heating temperature of the concentration means is higher than the heating temperature of the material in the container. This is to more reliably prevent liquefaction and solidification of the material in the concentration means and the flow path (pipe) around it. That is, in an actual apparatus, even when the concentration means is being heated, a locally low-temperature location (cold point) may occur in the gas temperature in the concentration means and the flow path around it. Therefore, by increasing the temperature of the concentration means, liquefaction and solidification of the material at the cold point can be more reliably prevented. As a result, a higher-concentration gas can be supplied more stably.

[0060] In other words, in the present invention, it is preferable that the heating temperature of the container is lower than the heating temperature of the concentration means. When concentration is not performed using a separation membrane as in the present invention, if the heating temperature of the container is lowered, the concentration of the supplied material gas will decrease. However, in the present invention, the concentration of the material gas can be increased by performing concentration using a separation membrane. Therefore, according to the present invention, it is possible to supply a high-concentration material gas while suppressing the decomposition of the material by lowering the heating temperature of the container.

Examples

[0061] In order to confirm the effects of the present invention, film formation by ALD was performed under the conditions shown in Table 1. At that time, the precursors and reactants shown in Table 1 were used as gases, and either one of the precursor and reactant gases was supplied by the method of the present invention. The compositions of the gas to be concentrated and the carrier gas are also shown in Table 1.

[0062] The concentration of the material contained in the gas (mixed gas) before concentration and the concentration of the material contained in the gas (concentrated gas) after concentration were measured by the FT-IR method, respectively. The measurement results are shown in Table 1. For comparison, concentration was not performed in Comparative Examples 1 to 7. Therefore, only the concentration before concentration is shown in Comparative Examples 1 to 7.

[0063]

Table 1

[0064] The film formation rate (Growth Per cycle: GPC, film formation amount per cycle) in each of the above examples was as shown in Table 1. The higher the GPC, the faster the film formation rate, indicating that film formation can be performed efficiently.

[0065] In addition, in some embodiments, the density, dielectric breakdown strength, and 1% HF WER (wet etch rate) of the obtained film were measured. The measurement results are shown in Table 1. The higher the film density, the denser the film was formed, which can be regarded as a good result. Also, the higher the dielectric breakdown strength, the higher the insulation property of the film, which can be regarded as a good result. Furthermore, the lower the 1% HF WER, the higher the hydrofluoric acid resistance, which can be regarded as a good result.

[0066] As can be seen from the results shown in Table 1, in the examples to which the present invention was applied, as a result of supplying the material gas in a concentrated manner, the film formation rate and the film quality were improved. This is presumably because the concentration of the material gas increased the partial pressure of the material gas during film formation and improved the collision frequency of the material gas with the substrate.

Explanation of Reference Numerals

[0067] 1 Supply device 10 Carrier gas flow path 11 Flow rate adjusting means 12 Valve 13 Valve 14 Bypass flow path 15 Valve 20 Container 30 Mixed gas flow path 31 Valve 32 Valve 33 Pressure measuring means 34 Pressure adjusting means 40 Concentration means 50 Concentrated gas flow path 51 Valve 60 Device 70 Exhaust flow path 71 Vacuum reducing means 72 Valve 100 Double-tube separator 110 Outer tube 120 Inner tube 121 Separation membrane

Claims

1. A supply method for supplying a gaseous material, comprising: a mixed gas preparation step of introducing a carrier gas into a container in which the material is contained in a solid or liquid state to obtain a mixed gas of the vaporized material and the carrier gas; a concentration step of obtaining a concentrated gas with an increased concentration of the material by removing the carrier gas in the mixed gas using a separation membrane; a supply step of supplying the concentrated gas to an apparatus that uses the material, wherein the concentration step is performed by a concentration means provided with a heating means.

2. The supply method according to claim 1, wherein the separation membrane has pores with an average diameter of 0.1 to 10 nm.

3. The supply method according to claim 1 or 2, wherein in the concentration step, a double-tube separator provided with the separation membrane is used.

4. The supply method according to claim 1 or 2, wherein in the concentration step, one side of the separation membrane is depressurized.

5. The supply method according to claim 1 or 2, wherein the material is at least one selected from the group consisting of aluminum chloride, hafnium chloride, zirconium chloride, tantalum chloride, tungsten pentachloride, tungsten hexachloride, molybdenum dichloride dioxide, molybdenum pentachloride, ruthenium chloride, hydrazine compounds, hafnium compounds, zirconium compounds, platinum compounds, ruthenium compounds, cobalt compounds, silicon compounds, aluminum compounds, titanium compounds, tantalum compounds, pure water, hydrogen peroxide, and organic solvents.

6. A supply apparatus for supplying a gaseous material, comprising: a container in which the material is contained in a solid or liquid state; a carrier gas flow path for introducing a carrier gas into the container; a mixed gas flow path for taking out a mixed gas of the vaporized material and the carrier gas from the container; a concentration means for obtaining a concentrated gas with an increased concentration of the material by removing the carrier gas in the mixed gas using a separation membrane; a concentrated gas flow path for supplying the concentrated gas to an apparatus that uses the material, wherein the concentration means is provided with a heating means.

7. The supply apparatus according to claim 6, wherein the separation membrane has pores with an average diameter of 0.1 to 10 nm.

8. The supply apparatus according to claim 6 or 7, wherein the concentration means is a double-tube separator provided with the separation membrane.

9. The supply apparatus according to claim 6 or 7, further comprising a pressure reduction means for depressurizing one side of the separation membrane.

10. The supply device according to claim 6 or 7, wherein the material is at least one selected from the group consisting of aluminum chloride, hafnium chloride, zirconium chloride, tantalum chloride, tungsten pentachloride, tungsten hexachloride, molybdenum dichloride dioxide, molybdenum pentachloride, ruthenium chloride, hydrazine compounds, hafnium compounds, zirconium compounds, platinum compounds, ruthenium compounds, cobalt compounds, silicon compounds, aluminum compounds, titanium compounds, tantalum compounds, pure water, hydrogen peroxide, and organic solvents.

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