JPH1192939A - Liquid raw material transporting device, thin coating forming device using it and formation of thin coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove a liq. raw material fed to a thin coating forming device and remaining in a communicating passage. SOLUTION: This liq. raw material transporting device has a vessel 5 for housing a liq. raw material, a vaporizer 3 for vaporizing the liq. raw material and a transporting means 4 for transporting the liq. raw material in the vessel 5 to the vaporizer. In this liq. raw material transporting device, a communicating passage 7 communicating the vessel 5 and the transporting means 4 via a valve 15 is provided with liq. purging means 11, 12, 13 and 14 for purging the communicating passage 7, a transporting means 4 and a communicating passage 8 between the transporting means 4 and the vaporizer 3 by liqs. for purging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid raw material transporting apparatus for transporting a liquid raw material, and more particularly, to a liquid raw material used for an apparatus for forming a thin film on a surface of a substrate such as a glass substrate, a semiconductor wafer, and a plastic sheet. Related to transport equipment.

[0002]

2. Description of the Related Art FIG. 1 is a view showing a liquid material transporting apparatus used in a conventional thin film forming apparatus.

In FIG. 1, reference numeral 1 denotes a reaction chamber in which a thin film is formed, 2 denotes an exhaust pump, 3 denotes a vaporizer (vaporizer) for vaporizing a liquid material, 4 denotes a mechanical micropump as a liquid material transport means, 5 is a container for accommodating the liquid raw material, 6 is a pressurized liquid raw material and a communication path 7 from the container 5.
Pressurizing means for supplying a gas to be supplied to the micro pump 4 through the 8 is a micro pump 4 and a vaporizer 3
Reference numeral 9 denotes a gas supply path connecting the vaporizer 3 and the reaction chamber 1. Reference numeral 10 denotes gas supply means for supplying gas to the vaporizer 3.

At the time of the thin film forming operation, an inert gas pressurized from the pressurizing means 6 is supplied into the container 5 to increase the pressure in the container, and the liquid material is introduced into the micropump 4 through the communication path 7.

[0005] The liquid raw material introduced into the micropump 4 is introduced into the vaporizer 3 through the communication passage 8 at a supply amount controlled by the micropump.

In the vaporizer 3, the liquid raw material is vaporized by the vaporizing gas introduced from the gas supply means 10, and the vaporized raw material gas is supplied to the reaction chamber 1 via the supply path 9 together with the vaporizing gas.

[0007]

In the conventional apparatus shown in FIG. 1, after completion of the thin film forming operation, the micro pump 4
Both the vaporizers 3 stop. At this time, the gas remaining in the supply path 9 is exhausted by the exhaust pump 2 and removed, but the liquid source remains in the communication paths 7 and 8. If the apparatus is left in such a state, the remaining liquid raw material may be decomposed, or an unwanted reaction may generate unnecessary by-products. This may cause clogging of the piping, malfunction of the micropump, clogging of the vaporizer, and the like.

[0008] It is an object of the present invention to provide a liquid material transporting apparatus capable of efficiently removing liquid material remaining in a communication path.

Another object of the present invention is to provide a liquid raw material transporting apparatus capable of removing the liquid raw material remaining in the communication passage without returning the liquid raw material into the container.

[0010]

In order to achieve the above object, a liquid material transport apparatus according to the present invention comprises a container (5) for containing a liquid material and a vaporizer (3) for vaporizing the liquid material. ) And transport means (4) for transporting the liquid raw material in the container (5) to the vaporizer, wherein the container (5) and the transport means (4) The communication path (7), the transportation means (4), and the transportation means (4) are connected to the communication path (7) communicating via the valve (15) when the vaporization operation of the device is stopped.
Liquid purging means (11, 12, 1) for purging a communication passage (8) between the gas and the vaporizer (3) with a purging liquid.
3, 14) are provided.

Preferably, an exhaust path for discharging the liquid material from the transport means (4) and the communication path (7, 8) is provided in the communication path (8).

Preferably, the communication path (7) includes:
Further, a gas purge unit is provided, and more preferably, a liquid trap is provided in the exhaust path.

Preferably, the exhaust path is connected to a vacuum pump, and the vacuum pump is a turbo pump.

The purging liquid is preferably anhydrous hexane or anhydrous benzene.

[0015] The means of transport is preferably a mechanical pump.

Preferably, the liquid raw material is an organic metal, and more preferably, the organic metal is an alkyl aluminum hydride.

The thin film forming apparatus according to the present invention is characterized in that the above-mentioned liquid source supply device is provided as source gas supply means.

Preferably, the thin film forming apparatus is C
It is a VD device.

The method for forming a thin film according to the present invention is characterized in that the method includes a step of vaporizing a liquid raw material, introducing the liquid raw material into a reaction chamber, and forming a thin film on a substrate using the above-described liquid raw material transport apparatus.

Here, after the completion of the thin film forming step, the transportation means (4), the communication path (7) and the communication path (8)
It is preferable that the method further includes a step of performing a liquid purging and a gas purging. Further, before the thin film forming step, the transporting means (4), the communication path (7) and the communication path (8) are liquid purged, It is preferable to further include a step of purging gas.

[0021]

Referring to FIG. 2, a description will be given of a CVD apparatus having a liquid material transporting apparatus according to an embodiment of the present invention.

The liquid source container 5 and the micropump 4 are connected by a communication path 7 via a valve 15. On the opposite side of the valve 15 from the container 5, a purge liquid supply path 11 for liquid purge is provided. Purging liquid supply path 1
On the upstream side of 1, a valve 12, a purging liquid container 13 containing a purging liquid, and a pressurized gas supply unit 14 for supplying a gas for pressurizing the purging liquid are provided. The pressurized gas supply means includes, for example, a known pump and piping. A purge liquid discharge path 17 is provided downstream of the communication path 8 connecting the micropump 4 and the vaporizer 3.

When purging the communication paths 7, 8 and the micropump 4, the valve 15 is closed to cut off the communication between the liquid material container and the communication path 7. The valve 18 of the discharge path 17 provided upstream of the vaporizer 3 is opened, and the valve 12 downstream of the purging liquid container 13 is opened to introduce a pressurized gas into the purging liquid container 13 to increase the pressure in the container. The purge liquid is supplied from the container 13 to the valve 12, the purge liquid supply path 11, the communication path 7, the micropump 4, the communication path 8, the discharge path 17, and the valve 18. It is sufficient that the pressure of the pressurized gas is approximately atmospheric pressure plus 1 atm.

Thus, the communication path 7, the micropump 4,
The liquid source remaining in the communication passage 8 is replaced with a purge liquid. If such a purging operation is performed using gas instead of the purge liquid, the liquid material in the dead space of the communication paths 7 and 8 and the micropump 4 is purged due to the difference between the density of the liquid material and the density of the gas. It cannot be replaced with a working gas, and eventually the liquid raw material remains in the dead space. According to the embodiment of the present invention, this problem is solved by using the purge liquid.

Next, a method of forming a thin film including such a purging operation will be described.

First, the reaction chamber 1 is evacuated by operating the pump 2. Next, the liquid source in the container 5 is pressurized by the pressurizing means 6, and the valve 15 is opened to supply the liquid source into the micropump 4. The micropump 4 mechanically pressurizes the liquid raw material 4 to control the supply amount, while the vaporizer 3
To supply. The raw material gas transported into the reaction chamber 1 with the supply rate controlled is placed on a substrate holder (not shown) in the reaction chamber 1 and chemically reacts on a heated substrate to form a thin film. The micropump pressurizes the liquid with a precisely defined cylinder and a precisely defined piston, so that the pressure and shipping charge can be precisely adjusted. Therefore, the supply amount of the vaporized gas to the reaction chamber through the vaporizer 3 can be precisely determined, and the deposition rate during thin film formation can be controlled.

After the step of forming a thin film in the reaction chamber is completed, the purging operation is performed as described above.

The valve 15 is closed, and the valves 12 and 18 are opened. The pressurized purge liquid in the purge liquid container 13 is supplied to the micropump 4 via the valve 12, the supply path 11, and the communication path 7, and further flows through the communication path 8, the exhaust path 17, and the valve 18. . The liquid material remaining in the communication paths 7 and 8 and the micropump 4 is discharged to the exhaust path 17 in a form of being pushed out by the purge liquid.

In the case of gas purging, it is difficult to remove the liquid raw material remaining in the dead space between the branch point 16 of the path from the source gas container and the path from the purging gas container and the valve 15. If the purge gas is sent at a high pressure in order to complete the purge operation promptly, the vacuum pump provided in the discharge system may be broken, which is not preferable. According to the present embodiment, the liquid material remaining in such a dead space can be easily removed, and the problem associated with high pressure can be solved.

The present invention is more suitably used as a liquid material transporting apparatus for a thin film forming apparatus. However, the thin film forming apparatus is not limited to thermal CVD, but may be plasma CVD, light C
The present invention can be applied to any general CVD apparatus such as VD. In addition, it can be used as a part of a reactive gas supply system of a reactive sputtering apparatus.

The liquid raw materials used in the present invention include silicon tetrachloride, tetraethoxysilane, trimethylgallium, trimethylindium, trimethylaluminum,
Triisobutylaluminum, dimethylaluminum hydride, diethylaluminum hydride, diisobutylaluminum hydride, copper diacetylacetonate, copper bisdipivaloylmethanato, copper bishexafluoroacetylacetonate, etc. Raw materials are preferably used.

As the purging liquid used in the present invention, an organic solvent such as hexane, benzene, alcohol and acetone can be used. Above all, anhydrous hexane and anhydrous benzene are preferable because they have no OH group.

FIG. 3 shows a liquid material transporting apparatus for a thin film forming apparatus according to another embodiment of the present invention.

The difference from the embodiment of FIG. 2 is that a vacuum pump 23 is provided in the exhaust system, a purge gas supply path 20, a valve 21 and a purge gas supply means 22 are provided in the purge liquid supply path 11 for gas purge. It is in.

In this embodiment, after the liquid purge is performed as described above after the formation of the thin film, the valve 1 in the purge liquid path is used.
2 is closed, the valve 21 of the purge gas path is opened, and the pressurized purge gas is supplied from the gas supply means 22 to the communication paths 7 and 8 and the micro pump 4 to replace the purge liquid with the purge gas.

As described above, when performing the gas purging, it is not necessary to supply the purge gas at a high pressure because all the liquid raw materials are replaced with the purging liquid. Accordingly, a high vacuum pump such as a turbo molecular pump can be used as the vacuum pump 23, and the gas purge can be completed in a short time.

FIG. 4 shows an apparatus in which a recovery container 24 for recovering liquid and a turbo molecular pump 25 are arranged in the exhaust system of FIG.
The purging liquid can be prevented from being directly introduced into the turbo-molecular pump 25 due to the presence of the recovery container 24.

FIG. 5 shows an example in which an exhaust system having a pump 25 and a recovery container 24 is attached to the vaporizer 3 via a valve 39, and a valve 40 between the vaporizer 3 and the reaction chamber 1 is closed to purge the gas. By doing so, the liquid raw material in the vaporizer can be sufficiently removed.

FIG. 6 shows a thin film forming apparatus having a liquid material transporting apparatus according to the present invention.

After the container 5 is filled with the liquid raw material, the valve 3
Opening 1 and 32 supplies a pressurized inert gas to the container 5 and the purging liquid container 13. At this time, the valve 21 of the purge gas path and the valve 33 of the liquid material outlet are closed.

The liquid material is supplied to the micropump 4 by opening the valve 33. At this time, the valve 12 for the purge liquid outlet, the valve 21 for the purge gas path, and the exhaust system 37
The valve 34 in the path to is closed.

The valve 35 between the micropump 4 and the vaporizer 3 is opened, and the liquid material is sent from the micropump 4 to the vaporizer 3. At this time, the valve 3 in the purge gas path
6 and the valve 37 to the exhaust system 43 are closed. At this time, since the vaporizer 3 is in a standby state for the vaporization operation by opening the valve 38 in the vaporization gas path, the valve 40 to the reaction chamber 1 and the exhaust system 43, and the valve 41 to the exhaust system, Is supplied to the vaporizer 3 and is vaporized and exhausted to the exhaust system 43 via the valves 40 and 41.

At this time, the pressure in the reaction chamber 1 is reduced by the turbo molecular pump 44 and the rotary pump 45.
Therefore, when the valve 42 to the reaction chamber 1 is opened and the valve 41 to the exhaust system 43 is closed, the vaporized source gas is supplied into the reaction chamber, and a thin film is formed on the heated substrate.

When the formation of the thin film is completed, the valves 42 and 40 are closed, the valve 39 is opened, the valve 37 is opened, and the valve 34 is opened. Since the exhaust system 43 is performing an exhaust operation at this time, liquid materials are removed to some extent from the communication paths 7 and 8, the micropump 4 and the vaporizer 3.

Next, valves 39, 37, 34 to the exhaust system
Is closed, and the valve 3 between the micropump 4 and the vaporizer 3 is closed.
5. Open the valve 40 at the outlet of the vaporizer 3 and the valve 41 to the exhaust system 43. Then, the purge liquid pressurized through the valves 31 and 32 is opened, and the valve 12 is opened to open the purge liquid through the communication path 7, the micropump 4, the valve 35, the communication path 8, the vaporizer 3, the valve 40 and the valve 41. Exhaust system 43
Send to. Thus, the liquid source is replaced with the purge liquid. Next, the valve 12 is closed to stop the supply of the purge liquid, and the valves 35, 40, and 41 are closed.

Next, after opening the valve 39, the valve 3
7, and then the valve 34 is opened.

When the piping is baked at about 500 ° C. by a heater (not shown) wound around the piping constituting the communication paths 7 and 8, the purge liquid completely flows into the exhaust system 43.

Also, if necessary, valves 21 and 36
Is opened and the purge gas is supplied, the communication paths 7, 8 and the micro pump 4 and the vaporizer 3 can be further purged.

The exhaust system 43 has, for example, a vessel 24 for trapping and recovering liquid, a turbo molecular pump 25, a rotary pump 46, and an internal heater (not shown) capable of heating to about 400 ° C., as shown in FIG. It has a detoxification device 47 and a temperature control device 48 for inactivating and detoxifying highly reactive substances.

[0050]

EXAMPLE Using the apparatus shown in FIG. 6, DMAH (dimethylaluminum hydride) was used as the alkyl aluminum hydride as the liquid material, anhydrous hexane was used as the purge liquid, and hydrogen was used as the gas for vaporization (this hydrogen was used as a reaction gas or carrier gas). Also works), and nitrogen was used as a purge gas.

DMAH gas vaporized by the vaporizer 3 was introduced into the reaction chamber together with hydrogen gas at 500 SCCM while quantifying the transport charge by the micropump 4, and the substrate temperature was set to 2
An aluminum film of 1.0 μm was formed on a 6-inch Si wafer at 00 ° C. and a pressure in the reaction chamber of 1.33 Pa. After completion of the aluminum film formation, valves 39, 37, and 34
Were opened in this order, and residual DMAH in the communication paths 7 and 8, the micropump 4, and the vaporizer 3 was discharged. Thereafter, the valves 39, 37 and 34 are closed, and the valve 3 of the liquid material container is closed.
3 was closed, the valves 32 and 12 of the purge liquid container were opened, and anhydrous hexane was charged into the communication paths 7 and 8, the micropump 4 and the vaporizer 3.

The valves 12 and 32 were closed to stop the supply of anhydrous hexane, and the valves 35, 40 and 41 were closed. Next, valves 39, 37, and 34 were opened in this order to remove residual anhydrous hexane.

Next, the communication paths 7 and 8 were baked at a temperature lower than the decomposition temperature of the raw material gas, that is, 100 ° C., which is less than 160 ° C. in the case of DMAH. Then, the valve 21
And the valve 36 is opened to introduce nitrogen gas.
By exhausting air from 4, 37 and 39, the insides of the communication passages 7 and 8, the micro pump 4 and the vaporizer 3 were purged with gas. The valves 21 and 36 are closed, the supply of purge gas is stopped, the valve 34 is closed and the valves 33 and 31 are opened to supply DMAH to the micropump 4, and the valve 35 is opened to supply DMAH to the vaporizer 3 from the micropump 4. Then, by returning to the source gas supply standby state, the film formation can be started again.

Thus, the film forming operation and the purging operation were repeatedly performed.

[0055]

As described above, according to the present invention,
The liquid source remaining in the path from the liquid source container to the vaporizer can be efficiently removed, and a highly reliable apparatus in which clogging of pipes and entry of impurities can be suppressed can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram of a liquid material transport device used in a conventional thin film forming apparatus.

FIG. 2 is a diagram of a thin film forming apparatus having one embodiment of a liquid material transporting apparatus according to the present invention.

FIG. 3 is a diagram of a thin film forming apparatus having another embodiment of the liquid material transporting apparatus according to the present invention.

FIG. 4 is a view showing still another embodiment of the liquid material transporting apparatus according to the present invention.

FIG. 5 is a view showing still another embodiment of the liquid raw material transport apparatus according to the present invention.

FIG. 6 is a diagram of a thin film forming apparatus having still another embodiment of the liquid material transporting apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction chamber 2 Exhaust pump 3 Vaporizer 4 Micro pump 5 Liquid material container 6 Pressurizing means 7, 8 Communication passage 9 Source gas supply path 10 Vaporizing gas supply means 13 Purging liquid container

Claims (15)

[Claims] 1. A liquid raw material transport comprising: a container for storing a liquid raw material; a vaporizer for vaporizing the liquid raw material; and transport means for transporting the liquid raw material in the container to the vaporizer. In the apparatus, when the vaporization operation of the apparatus is stopped, the communication path, the transportation means, and the communication between the transportation means and the vaporizer may be connected to a communication path communicating the container and the transportation means via a valve. A liquid material transporting device, comprising a liquid purging means for purging a passage with a purging liquid. 2. The liquid material transport apparatus according to claim 1, wherein an exhaust path for discharging the liquid material from the transport means and the communication path is provided in the communication path. 3. The liquid raw material transport apparatus according to claim 1, wherein a gas purge unit is further provided in the communication path. 4. The liquid material transport apparatus according to claim 2, wherein a liquid trap is provided in the exhaust path. 5. The liquid material transport apparatus according to claim 2, wherein the exhaust path is connected to a vacuum pump. 6. The liquid material transport apparatus according to claim 5, wherein the vacuum pump is a turbo pump. 7. The liquid material transport apparatus according to claim 1, wherein the purge liquid is anhydrous hexane or anhydrous benzene. 8. The liquid material transport apparatus according to claim 1, wherein said transport means is a mechanical pump. 9. The liquid raw material is an organic metal.
3. The liquid raw material transport device according to 1. 10. The liquid raw material transport apparatus according to claim 9, wherein the organic metal is an alkyl aluminum hydride. 11. A thin film forming apparatus, wherein the liquid raw material transport apparatus according to claim 1 is provided as raw material gas supply means. 12. The thin film forming apparatus according to claim 11, wherein said thin film forming apparatus is a CVD apparatus. 13. A method for forming a thin film, comprising the step of vaporizing a liquid material, introducing the liquid material into a reaction chamber, and forming a thin film on a substrate using the liquid material transport apparatus according to claim 1. 14. The thin film forming method according to claim 13, further comprising, after the thin film forming step, purging the transportation means, the communication path, and the communication path with a liquid, and further performing a gas purge. 15. The thin film forming method according to claim 13, further comprising, before the thin film forming step, purging the transportation means, the communication path and the communication path with a liquid, and further performing a gas purge.