JPH09143740A - Cleaning method for treating gas supplying system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method for a treating gas supplying system capable of effectively removing a high-viscosity liquid org. metallic material. SOLUTION: This method comprises supplying the high-viscosity liquid org. metallic material 16 to an vaporizing means 28 via a supplying passage 24 to vaporizing the material and to form a treating gas and supplies this treating gas to a treating device 42 to wholly or partially clean the entire part of the treating gas supplying system 14. The supplying passage part to be cleaned is heated in a temp. range where the viscosity of the org. metallic material is lowered and the thermal decomposition of the material does not arise. A purging gas is then passed to the supplying position part to expel the org. metallic material 16 lowered in the viscosity. An org. solvent which does not react with the org. metallic material is then introduced into the supplying passage part in the lowered viscosity state of the org. metallic material, by which the remaining org. metallic material is dissolved and the supplying passage part is cleaned. As a result, the gas purging is executed in the lowered viscosity state and, thereafter, the residual material is dissolved by the org. solvent, by which the approximately sure expulsion of the org. metallic material is made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a processing gas supply system, which supplies a highly viscous liquid by gasifying it to, for example, a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art In general, a semiconductor device tends to have a multilayer wiring structure in response to recent demands for higher density and higher integration. In this case, a lower device and an upper aluminum wiring are required. Embedding technology such as a contact hole as a connection portion with the via and a via hole as a connection portion between the lower aluminum wiring and the upper aluminum wiring has become important in order to make an electrical connection between them. It is preferable to use a cheap and highly conductive material such as aluminum for filling the contact holes and via holes, and it is highly directional in order to prevent the occurrence of voids due to the technical limitation of filling holes. CVD (Chemical Vapor Deposition) instead of sputtering
The film formation by the position) is desired.

To form an aluminum-CVD film,
Generally, DMAH which is an organic metal gas as a processing gas
(Dimethylaluminum hydride) is used, but this DMAH has a very high viscosity of about 8000 cp (centipoise) at room temperature and has a syrup-like form, and moreover, it reacts violently with moisture and oxygen in the air and ignites. It is a very difficult substance to handle.

As a method for gasifying a liquid material and supplying it as a processing gas, there are generally a bubbling method, a baking method and a direct vaporization method as shown in FIG. FIG. 3A shows a bubbling method, in which a carrier gas such as N ₂ gas whose flow rate is controlled by the mass flow controller 6 is supplied into the liquid material 2 stored in the liquid container 4 to cause bubbling, which occurs at this time. The DMAH gas is carried into the supply pipe 7 as a carrier gas and supplied to the processing device. FIG. 3B shows a baking method, in which the liquid container 4 in which the liquid material 2 is stored and the mass flow controller 6 for controlling the flow rate of the processing gas are housed in the same oven 8 and heated to heat the liquid material. 2 is directly vaporized by heat, and the processing gas is pressure-fed into the supply pipe 7 by the vapor pressure at this time and supplied to the processing apparatus.

FIG. 3C shows a direct vaporization method, in which a pressurized gas is supplied into a liquid container 4 in which the liquid material 2 is stored, and the pressure causes the liquid material in the container 4 to remain in the liquid state as a supply pipe. 7 is fed under pressure, and this supply amount is controlled by the liquid flow controller 1
It is poured into the vaporizer 12 while controlling the flow rate at 0. Then, in the vaporizer 12, the carrier gas whose flow rate is controlled by the mass flow controller 6 is vaporized, and the generated processing gas is supplied to the processing apparatus.

By the way, when the liquid material 2 is used up by repeating the film forming process, the container 4 is replaced, or trouble occurs in the mass flow controller 6, the liquid mass flow controller 10 or the vaporizer 12 for some reason. In this case, maintenance work must be performed by removing this from the piping of the supply system. During maintenance work, if the residual liquid material in the pipe is exposed to air or moisture, it may react with it to produce harmful substances, which may cause inconvenient reactions such as ignition. In order to eliminate the liquid material remaining in the portion of the pipe, the inside of this pipe is generally evacuated to perform a vacuum purge, or in combination with this, an inert gas such as N ₂ gas. Is purged into the pipe to forcibly discharge the remaining liquid material.

[0007]

By the way, when a gaseous material or an ordinary liquid material which is easily vaporized is used as the processing gas, it is easy to remove the liquid material remaining in the pipe by the above-mentioned vacuum purging or gas purging. Can be eliminated.
However, when a liquid material having a particularly high viscosity, for example, DMAH used when forming an Al film by CVD is used as the processing gas, this liquid material has a very high viscosity as described above, and therefore, the above-mentioned method is used. There was a problem that the residual liquid could not be sufficiently removed from the pipe wall even when the gas purge and the vacuum purge were used together.

The present invention focuses on the above problems,
It was created to solve this effectively. It is an object of the present invention to provide a cleaning method for a processing gas supply system, which can effectively remove a liquid high-viscosity organometallic material.

[0009]

In order to solve the above problems, the present invention supplies a liquid high-viscosity organometallic material to a vaporization means through a supply passage to vaporize it to form a processing gas. In the method of cleaning the processing gas supply system that supplies the processing gas to the processing apparatus wholly or partially, the supply passage portion to be cleaned is
The organometallic material is heated at a temperature that lowers the viscosity of the organometallic material and within a temperature range in which it does not thermally decompose, and a purging gas is caused to flow through the supply passage portion to eliminate the organometallic material whose viscosity is reduced. By introducing an organic solvent that does not react with the organic metal material into the supply passage portion while the viscosity of the metal material is reduced, the remaining organic metal material is dissolved and cleaned.

Since the present invention is configured as described above, the liquid organometallic material remaining in the supply passage is heated in a temperature range where it is not thermally decomposed and its viscosity is lowered, and gas purging is performed in this state. By doing so, most of the organometallic material is purged and removed, and further, an organic solvent is introduced into the supply passage to dissolve and clean the remaining organometallic material. In this case, a solvent that does not react with the organic metal material is used as the organic solvent, and for example, as the organic metal material, A
When DMAH (dimethylaluminum hydride) for film formation is used, the organic solvent for cleaning is a non-alcohol hydrocarbon solvent, for example, n.
(Normal) -hexane and n-dodecane can be used. The organic solvent introduced into the supply passage is discharged by vacuuming, but it is preferable to repeat the introduction and suction discharge of the organic solvent a plurality of times in order to completely perform cleaning.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a cleaning method for a processing gas supply system according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram showing a processing gas supply system for carrying out the cleaning method of the present invention. First, a processing gas supply system for carrying out the cleaning method of the present invention will be described. Here, a case will be described as an example in which liquid DMAH is used as an organic metal material in order to form an aluminum film by CVD, and this is vaporized and supplied to a processing apparatus.

As described above, this DMAH is 8 at room temperature.
It has a high viscosity of about 000 cp and is in a syrup-like liquid state. Further, while it is highly reactive and reacts violently with water vapor and oxygen in the air, it is extremely difficult to handle at temperatures above about 100 ° C. due to thermal decomposition and precipitation of metallic aluminum.

The processing gas supply system 14 is a liquid organic metal material for forming a processing gas for film formation, here DMAH16.
And a heating means 20 for heating the DMAH 16 to reduce the viscosity, a supply passage 24 connecting the liquid storage container 18 and the processing device 22, and the DMAH 16 having the reduced viscosity. It is mainly configured by a pressure feeding means 26 for pressure feeding to the supply passage 24 side, and a vaporization means 28 which is provided in the middle of the supply passage 24 and vaporizes DMAH which is pressure fed to form a processing gas.

Specifically, the liquid storage container 18 is made of, for example, a sealed container made of stainless steel and having a capacity of about 2 liters, and an electrolytic polishing process is applied to the inner wall so that gas, moisture and the like are hard to adhere. There is. The storage container 18 has a lower end located above the liquid level and is provided with a gas introduction pipe 32 with a container opening / closing valve 30 interposed therebetween.
A pressure feeding pipe 34 extending from the pressure feeding means 26 is connected via a joint 36 so that the gas for pressure feeding can be introduced into the container 18. In addition, in the storage container 18,
A lower end is immersed in the liquid, and a liquid outlet pipe 40 having a container opening / closing valve 38 is provided. The outlet side is connected to the supply passage 24 through a joint 42.

The heating means 20 includes joints 36 and 42.
The temperature sensor 44 is provided on the wall surface of the container 18, and the temperature control unit 46 supplies the heating means 20 based on the detection value of the sensor 44. By controlling the electric power to be applied, the DMAH 16 is always controlled to have an appropriate temperature. In this case, the heating temperature is set to a temperature range that only lowers the viscosity of DMAH16 and does not cause thermal decomposition, for example, in the range of 40 to 80 ° C., and is maintained at 50 ° C. in this embodiment. Therefore, the viscosity of DMAH is reduced to about 2000 cp.

The pressure feeding means 26 comprises, for example, an Ar gas cylinder 48 filled with a high pressure Ar gas of 5 kg / cm ² 2 and a pressure feeding pipe 34 connected to the Ar gas canister 48. In the middle of the pressure feeding pipe 34, first, second and Third on-off valves 50A, 50B, 50C
5 kg / c of DMAH 16 in the container 18
It is adapted to pumping at a pressure of m 2 ^2. A cylinder opening / closing valve 48A is provided at the outlet of the Ar gas cylinder 48,
It can be opened and closed. This Ar gas is also used as a purging gas at the time of cleaning as described later. On the downstream side of the third opening / closing valve 50C, a trap pipe 54 with a trap opening / closing valve 52 interposed in the middle is provided so as to be branched so that the gas in the pressure feeding pipe 34 can be degassed as necessary. Has become.

The supply passage 24 is made of a stainless steel tube having a diameter of, for example, 1/4 inch, which is large enough to allow the flowing DMAH to flow without causing excessive pressure loss. From the upstream side to the downstream side, a first opening / closing valve 56A, a liquid flow rate control means 58 for controlling the flow rate of the flowing liquid, a second opening / closing valve 56B, the vaporizing means 28 and a third opening / closing valve 56C are sequentially provided. Therefore, the DMAH flows as a liquid up to the vaporization means 28, is vaporized here, and thereafter flows in a gas state.

The vaporizing means 28 includes a carrier gas pipe 6
A hydrogen gas cylinder 62 that stores, for example, hydrogen gas as a carrier gas is connected via 0.
0 indicates the first opening / closing valve 64 from the upstream side to the downstream side.
A, mass flow controller 66 and second on-off valve 64B
The hydrogen gas can be supplied as the vaporized gas and the carrier gas by sequentially interposing. In addition, the supply passage 24 upstream of the first on-off valve 56A, between the liquid flow rate control means 58 and the second on-off valve 56B, and the vaporization means 28 and the third on-off valve 5.
From between 6C, trap tubes 68A and 68, respectively.
B and 68C are provided in a branched manner, and trap opening / closing valves 70A, 70B, and 70C are provided in the respective trap tubes. Incidentally, each of the trap tubes 54, 68A, 6
Although not shown, 8B and 68C are commonly connected,
A vacuum pump is installed on the way, and a vacuum is drawn during the trap.

The downstream side of the second on-off valve 50B of the pressure feed pipe 34 and the downstream side of the first on-off valve 56A of the supply passage 24 are connected by a communication pipe 74 having an on-off valve 72 in the middle. Further, a purge pipe 78 is provided, which connects the downstream side of the first on-off valve 50A of the pressure feeding pipe 34 and the downstream side of the second on-off valve 56B of the supply passage 24 and has an on-off valve 76 interposed in the middle thereof. DMAH by Ar gas during maintenance of piping system
Can be eliminated.

Here, the liquid container 18 and the vaporizing means 28
And the first opening / closing valve 56A, the liquid flow rate control means 58, and the second opening / closing valve 5 which are provided in the passage between them.
6B, and the trap pipe 6 including the open / close valve 72 of the communication pipe 74, the communication pipe 74 up to this point, and the trap open / close valve 70A.
8A, a trap tube 68B including a trap opening / closing valve 70B,
The on-off valve 76 and the purge pipe 78 so far are, for example, a first heater 80 (shown by a broken line) which is a tape heater.
Is entirely wound, and is heated to, for example, about 50 ° C., which is the same as that of the storage container 18, so as to keep the viscosity of the flowing liquid low.

Further, the vaporizing means 28 and the processing device 2 and the vaporizing means 28
A second heating heater 82 (shown by a broken line) made of, for example, a tape heater is also wound around the entire supply passage 24 between the second heating heater 2 and the trap pipe 68C including the third opening / closing valve 70C.
The vaporized DMAH is heated to a constant value within a temperature range in which it is neither reliquefied nor thermally decomposed, for example, 60 to 80 ° C. Furthermore, a third heater 84 such as a tape heater is also provided on the entire downstream side of the carrier gas pipe 60.
Is wound around and wound at a temperature similar to that of the vaporizing means 28, 60 to
It is heated in the range of 80 ° C. and preheats the flowing carrier gas to promote the vaporization of DMAH.

On the upstream side of the pressure feed pipe 34, Ar is provided.
In parallel with the gas cylinder 48, a solvent cylinder 88 for storing an organic solvent for cleaning is connected via a branch pipe 86, and a cylinder opening / closing valve 88A is provided at this outlet.
It can be opened and closed. Therefore, the Ar gas and the organic solvent can be selectively flown by operating the two cylinder opening / closing valves 48A and 88A. Here, as the organic solvent, an organic metal material, for example, a non-alcohol hydrocarbon-based organic solvent that dissolves DMAH without reacting with it, for example, n (normal) -hexane is used. In addition, n-dodecane may be used instead of n-hexane, but an alcohol solvent such as isopropyl alcohol is not preferable because it reacts with DMAH.

On the other hand, the liquid flow rate control means 58 and the vaporization means 2
8 and a mass flow controller 66 for controlling the flow rate of the carrier gas supplied thereto are controlled by a flow rate control unit (not shown) such as a microcomputer, and the vaporizing means 28 has a sufficient amount of carrier gas for vaporizing DMAH. Is always supplied.
In addition, the first, second and third heaters 80, 82, 8
4 are controlled to the above-mentioned temperature values by a temperature control unit 90 including, for example, a microcomputer.

Here, the structures of the liquid flow rate control means 58 and the vaporization means 28 will be described. As shown in FIG. 2, the liquid flow rate control means 58 is configured in substantially the same manner as a normal mass flow controller that detects a minute gas flow rate, but the normal mass flow controller heats the fluid to change the temperature according to the flow rate. On the other hand, in the case of DMAH, there is a risk of vaporization and thermal decomposition due to heating, so that it is possible to sense even if the temperature is high and the temperature change is detected according to the flow rate by cooling the fluid. The configuration is different from that of a normal mass flow controller in that the sensor tube is set to a tube diameter that can obtain a flow velocity of a certain degree and that does not impair the flow. That is, the sensor tube 9 connected to the supply passage 24 in FIG.
An electronic cooling element 94 such as a Peltier element is provided at 2, and the bridge circuit 96 detects the flow rate as a potential difference. The detected value is amplified by the amplifier circuit 98, and the temperature is corrected by the correction circuit 100, which constitutes the sensor 102.

The comparison control circuit 104 compares a set voltage commanded by a flow rate control unit (not shown) with the sensor detection value, and the valve drive circuit 106 is composed of, for example, a laminated piezoelectric element so that the deviation becomes zero. The actuator 108 is driven to control the valve opening of the piezo valve 110. In this case, the pipe diameter of the sensor pipe 92 is set to the predetermined flow rate of the liquid as described above, for example, 0.5.
A flow rate that can be detected by a sensor with respect to CCM (100 SCCM) is obtained, and a size that allows the flow of liquid even if the viscosity is as high as 2000 cp,
For example, in this embodiment, it is set to about 5 mm. If the tube diameter is too small, for example, about 1 mm, the viscosity of the tube is too great to allow it to flow, and for example, 10 m
If it is too thick, about m, the flow velocity will be too slow for the sensor to detect.

FIG. 3 shows the relationship between the flow direction and the detected temperature. In the figure, the solid line shows the characteristics when the liquid is not flowing, and the broken line shows the characteristics when the liquid is flowing. When the liquid flows, the temperature rise of ΔT is detected, but this rise is proportional to the flow rate, and the flow rate is obtained by electrically processing this temperature rise.

FIGS. 4 and 5 show the structure of the vaporization means 28. A liquid introduction port 114 is provided in the center of the valve body 112, and a carrier introduction port 116 and a gas discharge port 118 are provided on the opposite sides of the liquid introduction port 114 in the diametrical direction. To provide.
Then, on the outer periphery of the liquid introduction port 114, another port 1
Ring-shaped vaporization groove 120 so as to connect 16, 118
To form And, on the upper part of this valve body 112,
For example, a thin plate-shaped valve body 124 with a corrugation 122 that can be bent in the vertical direction is provided, and the valve is bent in the vertical direction by an actuator (not shown) to close the port or change the valve opening. .
Therefore, the liquid flowing out from the liquid introduction port 114 causes a pressure drop by flowing the controlled carrier gas, reaches the vaporization groove 120 while being vaporized by the Joule-Thomson effect, and can be transported as a processing gas together with the carrier. It has become. Also in this case, the carrier introduction port 116 and the pipe diameter of the pipe connected thereto are
Like the previous sensor tube 92, it is set to about 5 mm.

Now, returning to FIG. 1, the structure of the processing device 22 will be described. As the processing apparatus 22, a so-called single wafer type CVD for processing the semiconductor wafers W one by one
The device is shown as an example. A mounting table 130 heated by, for example, a resistance heater 128 is provided in a processing container 126 made of, for example, aluminum of this apparatus, and the wafer W is held on the upper surface of the mounting table 130 by, for example, a mechanical clamp 132. Placed. An electrostatic chuck may be used instead of the mechanical clamp 132. On the upper part of the container 126, a mounting table 130
A shower head 134 is provided facing to
A supply passage 24 for supplying a processing gas is connected to the shower head 134, so that the processing gas is introduced into the processing container 126. Further, an exhaust port 136 connected to the illustrated vacuum pump is provided at the bottom of the container so that the inside of the container can be evacuated.

Next, the operation of the processing gas supply system configured as described above will be described. First, an unprocessed semiconductor wafer W is loaded into the processing container 126 and placed on the mounting table 13.
0, the container 126 is evacuated to the base pressure, and the resistance heater 128 keeps the wafer W at a predetermined value within the process temperature range, 180 ° C. to 250 ° C., for example, 200 ° C. . And this container 12
While supplying a predetermined processing gas from the shower head 132 to the inside of the chamber 6, the inside of the chamber is in the process pressure range of 0.5 Torr to 10
While maintaining a predetermined value within the range of 0 Torr, for example, about 2 Torr, a film forming process of, for example, aluminum is performed.

Here, in order to supply the processing gas to the processing container 126, the high-viscosity syrup-like DMAH 16 is used as the organic metal material. However, the viscosity is too high as it is and it is supplied while controlling the flow rate. Can not do it. Therefore, in the present invention, the entire liquid storage container 18 for storing the DMAH 16 is covered with the oven 20 to heat the DMAH 16 to a predetermined temperature, for example, 50 ° C., to reduce the viscosity from about 8000 cp to about 2000 cp to facilitate the flow. . This heating temperature is within a temperature range in which the viscosity of the liquid organometallic material is lowered to some extent and vaporization or thermal decomposition is not caused, that is, in the case of DMAH, it is 40
The range of about 60 ° C to about 60 ° C is preferable.

The temperature of the storage container 18 is detected by the temperature sensor 44, and this is input to the temperature control unit 46 as a feedback signal so that it is always maintained at 50 ° C., for example. Here, the relationship between the temperature of DMAH and the viscosity will be described with reference to FIG. 6. At room temperature, for example, 25 ° C., the viscosity is as high as about 8000 cp, but it is 50 ° C.
When heated to a certain degree, the viscosity sharply drops to about 2000 cp. With the viscosity of the DMAH 16 lowered in this way, 5 kg from the Ar gas cylinder 48 of the pressure feeding means was used.
When Ar gas having a pressure of / cm ² 2 is introduced into the storage container 18 through the pressure feed pipe 34, the viscosity is lowered.
16 is smoothly pumped in the supply passage 24 by this gas pressure. The first, second and third on-off valves 50A, 50B and 50C provided on the pressure feed pipe 34 and the first, second and third on-off valves 56A and 50A provided on the supply passage 24 are provided.
Of course, 56B and 56C are opened, the cylinder opening / closing valve 48A of the Ar gas cylinder 48 is also opened, and the container opening / closing valves 30 and 38 are also opened. As the pressurized gas, other than Ar gas, other inert gas such as He gas and Xe gas can be used.

Liquid DMAH pumped in the supply passage 24
Is introduced into the vaporizing means 28 while flowing while the flow rate is controlled by the liquid flow rate controlling means 58. The liquid DMAH introduced into the vaporization means 28 is vaporized by the high-pressure hydrogen gas supplied from the hydrogen gas cylinder 62 via the carrier gas pipe 60 to the processing gas by the Joule-Thomson effect, and the processing gas generated here is generated. Accompanying hydrogen gas, the gas flows further downstream in the supply passage 24 to reach the processing device 22, and is finally introduced into the processing container 126 from the shower head 132 as described above.

Here, the passage portion in which the flowing DMAH is in a liquid state, that is, the supply passage 24 and the liquid flow rate control means 58 on the upstream side of the vaporization means 28 are accommodated by the wound first heater 80. Since the temperature is maintained at substantially the same temperature as that of the container 18, for example, 50 ° C., it is possible to prevent the viscosity of the liquid DMAH from lowering during the supply, which may hinder the supply. Further, the vaporizing means 28 and the supply passage 24 on the downstream side thereof are heated by the wound second heater 82 in a temperature range not lower than the vaporization temperature of DMAH and not higher than the thermal decomposition temperature, for example, in the range of 60 ° C. to 80 ° C. Since it is heated, the vaporized gas of DMAH, that is, the processing gas does not reliquefy and is not thermally decomposed, and it can be smoothly supplied to the processing device 22 by flowing through this passage.

Further, a third heater 84 is wound around the carrier gas pipe 60 through which the carrier gas flows, so that the carrier gas introduced into the vaporizing means 28 has the same temperature as that of the vaporizing means 28, for example, 60 ° C. to 80 ° C. Since the liquid DMAH is preheated within the range of ° C, the liquid DMAH can be vaporized quickly and smoothly. In addition to H ₂ gas, an inert gas such as Ar gas or He gas can be used as the carrier gas. As described above, under the high-precision flow rate control, the conventional apparatus could supply only about 4 SCCM at most, but here, the flow rate required to mass-produce aluminum on one wafer W is required. For example, it becomes possible to supply DMAH with a large flow rate of about 100 SCCM (0.4 CCM in terms of liquid) while controlling it with high accuracy. Therefore, Al on a mass production basis
-CVD film formation becomes possible, and the process of filling contact holes and via holes can be performed on a mass production basis by Al-CVD film formation.

By the way, when the residual DMAH 16 in the liquid storage container 18 decreases or disappears as a result of repeating the film forming process, the empty storage container 18 is replaced with a new storage container filled with DMAH. 18, the liquid flow rate control means 58 and the vaporization means 28 are regularly or irregularly maintained, or maintenance such as replacement of deteriorated pipes is irregularly performed. Be done. In this case, if the DMAH remaining in the pipes or passages comes into contact with moisture or oxygen in the air and reacts violently as described above, the residual DMAH is previously removed from the inside of the pipes that will be exposed to the air. Need to be cleaned. First, the case where the liquid storage container 18 is replaced with a new storage container filled with DMAH will be described. In this case, at least the residual DMAH in the portion of the supply passage 24 between the container opening / closing valve 38 and the first opening / closing valve 56A must be reliably eliminated.

First, since the film forming process is interrupted as a matter of course, the first and second films provided in the supply passage 24 are provided.
Also, the respective valves of the third opening / closing valves 56A, 56B, 56C are closed and the supply of DMAH is stopped, and both container opening / closing valves 30, 38 attached to the storage container 18 are also closed to close the inside of the container 18. Is closed. Further, the first, second and third opening / closing valves 50A, 50B, 50C provided in the pressure feeding pipe 34.
Are also closed, and the supply of Ar gas is stopped. Here, in order to reduce the viscosity of the DMAH remaining in the supply passage 24 and maintain it in a state where it easily flows, the supply passage 2
The first heater 80 wound on the upstream side of No. 4 is continuously energized, and this is heated and maintained at the same temperature for lowering the viscosity as during film formation, for example, 50 ° C. This heating temperature is, of course, the thermal decomposition temperature of DMAH, for example, 1
Of course, the temperature is set lower than 00 ° C. By energizing the first heater 80, the trap tube 68A
Is also heated to the above temperature.

Since the residual DMAH in the pipe is thus made low in viscosity, the cylinder opening / closing valve 48A of the Ar gas cylinder 48 and the first and second opening / closing valves 50A, 50 of the pressure feeding pipe 34 are formed.
By opening B, the opening / closing valve 72 of the communication pipe 74, and the trap opening / closing valve 70A of the trap pipe 68A, high-pressure Ar gas is caused to flow in accordance with the above-described path, and the space between the container opening / closing valve 38 and the first opening / closing valve 56A is changed. DM remaining in the supply passage
AH is purged out of the system through the trap tube 68A and eliminated. At this time, in order to promote the purge of DMAH,
Of course, the trap tube 68A is evacuated by a vacuum pump (not shown).

Here, although the viscosity is lowered by heating, it is inevitable that DMAH adheres to and remains on the inner wall of the pipe. Next, the cylinder opening / closing valve 48A of the Ar gas cylinder 48 is closed. The supply of Ar gas is stopped, and the cylinder opening / closing valve 88A of the solvent cylinder 88 is opened instead, and n-hexane as a solvent is introduced into the same path as described above and poured in, and DMAH adhering to the inner wall of the pipe is mixed with this solvent. Dissolve in and eliminate. In this case, n-hexane may be continuously introduced while being removed from the trap tube 68A, but not limited to this, for example, when the solvent reaches the trap tube 68A, the trap opening / closing valve 70A is temporarily closed. The solvent may be retained in the tube for a while, for example, for about 20 seconds to accelerate the dissolution of DMAH, and then the top opening / closing valve 70A may be opened again to discharge the solvent out of the system.

When the dissolution with the solvent is completed, the cylinder opening / closing valve 88A of the solvent cylinder 88 is closed again to stop the supply of the solvent, and then the cylinder opening / closing valve 48A of the Ar gas cylinder 48 is opened again. The solvent in the pipe is reliably removed from the trap pipe 68A by introducing and flowing Ar gas. When the purge of the residual DMAH of the maintenance target portion is completed in this manner, next, the trap opening / closing valve 52 of the other trap tube 84 is opened and the pressure feeding pipe 34 is opened.
The pressure is released on the downstream side of the third opening / closing valve 50C. still,
This depressurization may be performed at any point during maintenance. When this pressure release is completed, the joints 36, 4
The liquid storage container 18 may be removed by releasing 2, and a new storage container may be attached instead of this.

As described above, first, the residual DMAH is heated to maintain it in a low viscosity state, and in this state, most of the DMAH is removed by gas purging, and further, an unreacted organic solvent is flowed to the tube wall. Since the residual DMAH is dissolved and purged, the residual DMAH can be reliably removed. Further, as the organic solvent, a solvent which is unreactive with the organic metal material is used, and therefore, the metal is not deposited in the pipe due to the reaction. In this embodiment, the case where the solvent is supplied only once has been described, but the present invention is not limited to this, and the supply and the discharge of the solvent are repeated a plurality of times so that the DMAH can be completely purged. Good.

Next, the case where the liquid control means 58 is maintained will be described. Also in this case, as in the case of the previous container replacement, the maintenance target part is isolated,
The remaining viscosity of DMAH is kept low, and a procedure of gas purging and dissolving with a solvent is performed. First, in a state where all the on-off valves are closed and the movement of the supply system is stopped, the first heater 80 wound around the supply passage 24 is provided.
Is continuously energized, and residual DMA is applied as described above.
The viscosity of H is lowered and maintained at a temperature at which it is not thermally decomposed, for example at 50 ° C. As a result, the viscosity of the DMAH remaining in the liquid flow rate control means 58 and the supply passage 24 is reduced, and the DMAH easily flows.

Next, the cylinder open / close valve 48A of the Ar gas cylinder 48 and the first and second open / close valves 50A, 50 of the pressure feed pipe 34 are shown.
B, open / close valve 72 of communication pipe 74 and liquid flow rate control means 58
The trap opening / closing valve 70B of the upstream side of the trap pipe 68B is opened, and high-pressure Ar gas is caused to flow along this path to remain in the liquid flow rate control means 58 and in the supply passage 24 on the upstream side of the second opening / closing valve 56B. Most of the DMAH to do
Are removed by gas purging. Here, the trap tube 68
If the trap opening / closing valve 70A of A is opened with a time difference, for example, the container opening / closing valve 38 and the first opening / closing valve 5 are opened as described above.
The DMAH remaining in the supply passage 24 between 6A and 6A can also be eliminated.

Next, the cylinder opening / closing valve 48A of the Ar gas cylinder 48 is closed to stop the supply of the Ar gas, and the cylinder opening / closing valve 88A of the solvent cylinder 88 is opened to open the n of the solvent.
-Hexane is introduced into the above-mentioned path and poured, and DMAH adhering to the inner wall of the pipe and the inside of the flow rate control means 58 is dissolved and removed with this solvent. Also in this case, n−
Hexane may be continuously introduced while being removed from the trap pipe 68B, but the present invention is not limited to this, and when the solvent reaches the trap pipe 68B, the trap opening / closing valve 70B is used.
Is closed once and the solvent is retained for a while to accelerate the dissolution of DMAH, and then the trap opening / closing valve 70B is opened again to discharge the solvent out of the system. Good.

When the dissolution with the solvent is completed, the cylinder opening / closing valve 88A of the solvent cylinder 88 is closed again to stop the supply of the solvent, and then the cylinder opening / closing valve 48A of the Ar gas cylinder 48 is opened again. By introducing Ar gas and flowing the Ar gas, the solvent introduced previously is trapped in the pipe 68B.
Eliminate more reliably. The trap opening / closing valve 70A of the trap pipe 68A is provided on the downstream side of the control means 58.
The opening / closing operation may be performed in synchronization with the trap opening / closing valve 70B of B or by slightly delaying the time in order to preferentially remove the DMAH on the control means 58 side. If the capacity of the supply passage portion between the first opening / closing valve 56A and the first opening / closing valve 56A is very small, the DMAH in this portion may be ignored and the trap opening / closing valve 70A may be kept closed during the above-described operation.

Also in this case, the solvent may be supplied and discharged a plurality of times repeatedly in order to ensure the removal of DMAH, as in the cleaning operation when the storage container is replaced. When the cleaning is completed in this way, the liquid flow rate control means 58 may be removed from the supply passage 24 and this maintenance may be performed. Next, a case where maintenance of the vaporizing means 28 is performed will be described. In this case as well, as in the case of the previous container replacement, the maintenance target portion is isolated to maintain the viscosity of the residual DMAH low, and the procedure of gas purging and solvent dissolution is performed.

First, with all the on-off valves closed and the movement of the supply system stopped, the second coil wound around the supply passage is closed.
The heater 82 is continuously energized to reduce the viscosity of the residual DMAH as described above and to maintain the temperature at which it does not thermally decompose, for example, 50 ° C. The heating temperature may be set to be the same as the reliquefaction prevention temperature of 60 ° C. to 80 ° C. during film formation. Further, since there is a short distance between the supply passage 24 on the upstream side of the vaporizing means 28 and the position where the purge pipe 78 is connected, the viscosity of the residual DMAH in this portion is also reduced. The first heater 80 is also energized to maintain this passage at, for example, 50 ° C.

Next, the cylinder open / close valve 48A of the Ar gas cylinder 48, the open / close valve 90 of the purge pipe 78, and the top pipe 68C.
The trap on-off valve 70C is opened, and high-pressure Ar gas is caused to flow in accordance with this path, and most of the DMAH remaining in the vaporization means 28 and the supply passage 24 between the second on-off valve 56B and the third on-off valve 56C. Are removed by gas purging. Next, the cylinder open / close valve 48A of the Ar gas cylinder 48 is closed to stop the supply of Ar gas, and the cylinder open / close valve 88A of the solvent cylinder 88 is opened instead to introduce the solvent n-hexane into the above-mentioned path. The solvent is poured and DMAH adhering to the inner wall of the pipe and the inside of the vaporizing means 28 is dissolved and removed with this solvent. Also in this case, n-hexane may be continuously introduced while being removed from the trap tube 68C, but the present invention is not limited to this, and once the solvent reaches the trap tube 68C, the trap on-off valve 70C is temporarily turned on. As in the case described above, the solvent may be retained for a while to accelerate the dissolution of DMAH, and then the trap on-off valve 70B may be opened again to discharge the solvent out of the system. .

When the dissolution with the solvent is completed, the cylinder opening / closing valve 88A of the solvent cylinder 88 is closed again to stop the supply of the solvent, and then the cylinder opening / closing valve 48A of the Ar gas cylinder 48 is opened again. The Ar gas is introduced into the trap tube 6 to flow the Ar gas.
Eliminate from 8B surely. In this case as well, similar to the cleaning operation at the time of replacing the storage container, the supply and discharge of the solvent may be repeated a plurality of times to ensure the removal of DMAH. When the cleaning is completed in this manner, the vaporizing means 28 may be removed from the supply passage 24 and the maintenance may be performed.

When the supply passage 24 is replaced, the supply passage portion to be replaced may be cleaned by appropriately combining the above-mentioned cleaning operations to eliminate DMAH. As described above, according to the present invention, a liquid high-viscosity organometallic material is caused to flow into a supply system to be vaporized to form a processing gas, and the processing gas is sent to a processing apparatus for film formation. When performing maintenance work, etc., the part to be maintained is heated at a temperature below the thermal decomposition temperature of the organometallic material to reduce the viscosity of the organometallic material and make it easier to flow. By doing so, most of the organometallic material is removed, and further, an organic solvent that is non-reactive with this metal material is introduced to dissolve and remove the remaining organometallic material, so that it is efficient and reliable. The supply system can be cleaned by removing the organometallic material.

In the above embodiment, the supply system of the supply system has been described by way of example in which the organometallic material is heated to reduce its viscosity, and pressure-fed in this state to be vaporized. Of course, it can be applied to a bubbling type supply system and the like. Further, it is needless to say that the present invention is not limited to the case of forming a film on a semiconductor wafer, and can be applied to the case of forming a film on another object to be processed such as an LCD substrate or a glass substrate.

[0051]

As described above, according to the cleaning method of the processing gas supply system of the present invention, the following excellent operational effects can be exhibited. The supply passage portion to be cleaned is heated to reduce the viscosity of the remaining liquid organometallic material, and gas purging is performed in this state to remove most of the organometallic material.
Since the organic solvent that does not react with the metal material is introduced to dissolve and remove the remaining organic metal material, cleaning can be performed quickly and reliably. Therefore, a highly reactive or dangerous organometallic material does not remain in the pipe, and the replacement of the liquid storage container and various maintenance operations can be performed quickly and safely. Particularly, cleaning can be surely performed by repeating the operation of introducing the organic solvent and the operation of removing the suction a plurality of times.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a processing gas supply system for carrying out a cleaning method of the present invention.

FIG. 2 is a schematic configuration diagram of a liquid flow rate control unit.

FIG. 3 is an operation explanatory view showing an operation of the flow rate control means shown in FIG.

FIG. 4 is a schematic sectional view showing a vaporizing means.

5 is a plan view of the vaporizing means shown in FIG. 4. FIG.

FIG. 6 is a graph showing the relationship between temperature and viscosity of DMAH.

FIG. 7 is a schematic configuration diagram showing a conventional processing gas supply system.

[Explanation of symbols]

 14 processing gas supply system 16 DMAH (organic metal material) 18 liquid storage container 20 heating means 22 processing device 24 supply passage 26 pressure feeding means 28 vaporization means 34 pressure feeding pipe 36 joint 42 joint 48 Ar gas cylinder 48A cylinder opening / closing valve 52 trap opening / closing valve 54 Trap tube 62 Hydrogen gas cylinder 68A, 68B, 68C Trap tube 70A, 70B, 70C Trap opening / closing valve 78 Purge tube 80 First heating heater 82 Second heating heater 84 Third heating heater 88 Solvent cylinder 88A Bottle opening / closing valve W Semiconductor Wafer

Claims (6)

[Claims] 1. A processing gas supply system for supplying a processing gas to a processing apparatus by supplying a liquid high-viscosity organometallic material to a vaporizing means through a supply passage to vaporize the processing gas and supply the processing gas to a processing apparatus. In the method of selectively or partially cleaning, the supply passage portion to be cleaned is heated at a temperature at which the viscosity of the organometallic material is lowered and in a temperature range in which it does not thermally decompose, and the supply passage portion is purged with a gas for purging. To remove the organometallic material whose viscosity has decreased, and then introduce an organic solvent that does not react with the organometallic material into the supply passage portion while the viscosity of the organometallic material is reduced. A method for cleaning a processing gas supply system, characterized in that the organic metal material for cleaning is dissolved and cleaned. 2. The method for cleaning a processing gas supply system according to claim 1, wherein the organometallic material is dimethyl aluminum hydride. 3. The cleaning method for the processing gas supply system according to claim 1, wherein the organic solvent is a non-alcohol hydrocarbon organic solvent. 4. The cleaning method for a processing gas supply system according to claim 1, wherein the heating temperature is 80 ° C. or lower. 5. The method for cleaning a processing gas supply system according to claim 1, wherein the introduction of the organic solvent and the suction and discharge are repeated a plurality of times. 6. The organic solvent is n-hexane or n-hexane.
-The cleaning method for the processing gas supply system according to claim 1, wherein the cleaning gas supply system is dodecane.