JPH04311570A - Film forming device provided with deposit recovering device - Google Patents

Abstract

PURPOSE:To highly economically and efficiently perform CVD in the film forming device by CVD using metal fluorides as the raw material by cleaning off the deposit in the CVD device, recovering and reusing the generated fluorides. CONSTITUTION:The metal fluorides (WF6, etc.) as the raw material hydrogen, hydrocarbons, etc., are supplied to a CVD device from a raw gas feeder to form a film, and the fluorides, etc., in the waste gas are absorbed in a waste gas cleaning device. At this time, a cleaning gas feeder is connected to the CVD device through a pipeline, cleaning gases (F2 gas, ClF3 gas) are sent to the CVD device or the waste gas cleaning device to clean off the deposit. The deposit is converted to the fluoride by the cleaning gas, and the fluoride is introduced into a fluoride recovering and supplying device, stored and then used as the raw gas.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is directed to a film forming apparatus using a CVD method using a metal fluoride as a raw material, which is capable of producing a film or a plate-like body of a metal or its compound of extremely high purity. The present invention relates to a method in which deposits in an apparatus are cleaned with fluorine gas (hereinafter abbreviated as F2 gas) or ClF3 gas, and the fluoride gas obtained by the reaction is recovered and used again as a raw material gas.

0002

[Prior art and its problems] Conventionally, tungsten (W)
, a method for obtaining metal or metal compound films or metal plates by reductive thermal decomposition of fluorides such as molybdenum (Mo), rhenium (Re), and iridium (Ir) using the CVD method (Japanese Unexamined Patent Publication No. 59-123765) etc.) is extremely useful as a method for obtaining high-purity metal films, and is widely used in the production of conductive wires such as ICs and the production of corrosion-resistant and abrasion-resistant materials.

[0003] Furthermore, methods for producing carbides and nitrides by reacting with gases such as hydrocarbons and nitrides are also known (Japanese Patent Application Laid-Open Nos. 61-84375 and 1983-15).
7681 etc.). However, in order to remove the metal or its compound deposited in a location other than the intended location from the CVD device, the device must be disassembled, which is a problem from the viewpoint of production efficiency. Also, among the metals mentioned above, especially Re, Ir, etc., are expensive, so
It is not economical to dispose of it as is.

0004

[Means for Solving the Problems] In view of the above problems, the inventors of the present invention have made extensive studies, and as a result, the metals or their compounds deposited in the CVD apparatus are once again treated with F2 gas or carbon dioxide.
Convert to fluoride by contacting with lF3 gas,
The present invention was achieved by completing a device in which gas is recovered into a container using a cooling device and then used again as a raw material gas.

That is, the present invention provides an apparatus for forming a film of a metal or its compound by the CVD method using a metal fluoride as a raw material, which is equipped with a raw material gas supply device, a CVD device, and an exhaust gas removal device, and further includes piping connected to the CVD device. The present invention provides a film forming apparatus equipped with a deposit recovery device, characterized in that it is equipped with a cleaning gas supply device and a fluoride recovery and supply device.

An example of a conceptual diagram of the apparatus of the present invention is shown in FIG. First, the raw material gas used in the apparatus of the present invention is W.
F6, MoF6, ReF6, IrF6, etc., hydrogen, hydrocarbons, ammonia, amine compounds, etc. are added to the gas, mixed, and heated in a CVD apparatus to form metals corresponding to the fluoride, their carbides, and nitrides. A film or plate-like body is deposited.

CVD equipment has heating methods such as resistance heating type, high frequency induction heating type, infrared lamp heating type, etc. For each of the above heating methods, there are hot plate type and core type, but the equipment itself Any type of material that is a completely closed system can be used in the present invention.

[0008] In addition to the target location, the above device can also
Films and powdery substances accumulate in various places inside the equipment and in piping, etc., and in order to remove them, the equipment must be dismantled and cleaning work performed, which not only interrupts operations but also causes problems. , it is difficult to remove completely and may cause contamination with impurities. Furthermore, if expensive metals such as Re and Ir are discarded as they are, the utilization rate of the metal will be low, which will be a major cause of an increase in manufacturing costs.

[0009] In the present invention, metals or their compounds adhering to these devices can be removed by F2 without dismantling the devices.
A cleaning process is performed using a cleaning gas such as gas or ClF3 gas, and the fluoride obtained by the cleaning process is further cooled to separate it from other gases and condense, and this gas is used again as a raw material gas for CVD. be.

[0010] Therefore, the raw material supply device of the present invention includes a cylinder storing the gas such as WF6, MoF6, ReF6, IrF6, etc., a flow rate control device for supplying the gas, and hydrogen or methane to be mixed with the gas. , cylinders for hydrocarbons such as ethane, propane, and benzene, or nitrogen compounds such as ammonia and dimethylamine, and a flow rate control device for supplying these gases. These gases are mixed in the piping before being introduced into the CVD apparatus, or in some cases are separately introduced into the CVD apparatus and mixed within the apparatus.

[0011] These mixed gases are heated in a CVD apparatus, and films or plate-like bodies of metals such as W, Mo, Re, and Ir, their carbides, and nitrides are produced according to their respective reactions. At that time, films and powders of the metals, their carbides, nitrides, etc. are deposited inside the CVD apparatus and in the piping afterward, depending on the temperature and atmosphere of the area.

[0012] Fluorides, chlorides, etc. of the exhaust gas exiting the CVD apparatus are absorbed by an exhaust gas abatement device, and other gases are discharged. The exhaust gas abatement device absorbs,
Fixed.

If necessary, if an absorbent such as activated carbon or zeolite is provided after the layer, trace amounts of fluoride and chloride passing through the layer can be completely removed.

Next, there is a cleaning gas supply device that supplies gas for cleaning deposits, and like the raw material gas supply device, this device also has cylinders and flow rates for storing the cleaning gases F2 gas and ClF3 gas. It consists of a control device.

[0015] The pipe coming out of the cleaning gas supply device is connected to the CVD device, whereby the cleaning gas is inserted into the pipe leading to the CVD device or the exhaust gas abatement device, and a cleaning process is performed.

[0016] In order to carry out the cleaning treatment, it is necessary to heat any deposits to a temperature of 100 to 400°C. In order to perform CVD, a CVD apparatus naturally requires a heating device equipped with a temperature control device, and when cleaning is performed using this heating device, the temperature may be set to the above-mentioned temperature. In addition, the piping leading to the exhaust gas abatement equipment is
It is preferable to provide a heating device in case deposits are attached.

Since the CVD apparatus and heating piping come into contact with the CVD source gas and cleaning gas in a heated state, it is preferable to use a corrosion-resistant material such as Ni or Monel.

In the CVD apparatus, each of the metals described above is converted into fluoride by a cleaning gas and introduced into the fluoride recovery and supply apparatus. In the fluoride recovery and supply device, the introduced fluoride gas is cooled and condensed using a refrigerant, and then stored in a cylinder. In this case, the particles are once aggregated and solidified in the trap, and after the atmospheric gas is once exhausted, the particles are aggregated and stored again in a storage cylinder. The temperature during trapping is below 0°C for WF6, M
In the case of oF6, ReF6, and IrF6, cooling to 0°C is sufficient.

Next, there is a case where the deposit is a carbide or a nitride. In this case, fluoride carbon, fluoride carbon,
Since nitrogen fluoride is also produced, it is necessary to separate the carbon fluoride or nitrogen fluoride from the fluorides of each metal. However, since carbon fluoride and nitrogen fluoride have lower boiling points than the metal fluorides mentioned above, only the metal fluoride can be trapped by cooling at a temperature of about 0 to -30°C. The subsequent operations are similar to those for aggregating only metal fluoride. Further, the fluorocarbon and nitrogen fluoride that have passed through the trap are removed by an exhaust gas removal device.

The fluoride thus stored is supplied with fluoride gas by a device similar to the raw material gas supply device, and other hydrogen, hydrocarbon, nitride gases, etc. are supplied from the raw material gas supply device, A desired film or plate-like body can be created by mixing with a gas.

By using the apparatus of the present invention as described above, it is possible to clean unnecessary deposits accumulated in the piping connected to the CVD apparatus or the exhaust gas abatement apparatus, and the obtained fluoride can be removed. Since it can be used again as a raw material gas, CVD operations can be performed extremely economically and efficiently.

[0022]

[Examples] The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 WF6 was used as a raw material gas, and hydrogen gas was mixed with this gas so that WF6:H2 (molar ratio) = 1:7, and the mixture was introduced into a CVD apparatus.

[0024] The CVD device has a diameter of 50 mm x 300 mm.
A nickel tubular furnace of size L was equipped with a heater equipped with a temperature control device, and a 30 x 30 x 2 mm Ni substrate was placed in the center of the furnace. The total flow rate was 1.2 L/min, the furnace temperature was set at 450 °C, and the reaction was carried out at a pressure of 760 Torr for 3 hours.
A W plate-like body measuring 30×0.6 mm was obtained.

When the inside of the tube furnace was observed when the plate-shaped body was taken out, it was found that film-like substances and powdery substances were deposited on the surface. After taking out the plate and sealing the tubular furnace again, it is evacuated, and the inside of the system is replaced with nitrogen gas. After evacuating, a mixed gas of fluorine gas (400 cc/min) and nitrogen gas (1.6 L/min) is added. introduced as
Cleaning treatment was performed at 250°C.

The cleaned gas was introduced into a fluoride recovery device, and WF6 was coagulated and solidified in a trap filled with a -20° C. refrigerant. Next, after evacuating the atmospheric gas, the storage cylinder was similarly
It was agglomerated into storage cylinders by cooling to 20°C and conversely heating the trap layer to 20°C. The amount of WF6 obtained at this time was 280 g.

The exhaust gas that has gone through the film forming process or the exhaust gas that has exited the trap after the cleaning process has an inner diameter of 400 mm,
A fixed bed reactor with a height of 900 mm and an internal diameter of 50 mm
It was introduced into an exhaust gas abatement device having an adsorbent packed bed with a height of 50 mm and a height of 50 mm. Soda lime 75 for the fixed bed reactor
kg, and 200 g of activated carbon was charged as an adsorbent.

By the treatment in the above-described apparatus, the halogen gas and halogenated gas were absorbed and fixed, and the harm was removed. Example 2 MoF6 was used as a raw material gas, hydrogen gas was mixed with this gas so that MoF6:H2 (molar ratio) = 1:7, and the mixture was introduced into a CVD apparatus.

The CVD apparatus is the same as in the first embodiment. The total flow rate was set at 1.2 L/min, the furnace temperature was set at 550 °C, and the reaction was carried out at a pressure of 760 Torr for 3 hours.
A Mo plate-like body of 0 x 30 x 0.6 mm was obtained.

When the inside of the tube furnace was observed when the plate-shaped body was taken out, it was found that film-like substances and powdery substances were deposited on the surface. The plate was taken out, the tubular furnace was sealed again and evacuated, and the system was replaced and evacuated with nitrogen gas, and a mixed gas of ClF3 gas (400 cc/min) and nitrogen gas (1.6 L/min) was added. A cleaning treatment was performed at 300°C.

The cleaned gas was introduced into a fluoride recovery device, and MoF6 was coagulated and solidified in a trap filled with a 0° C. refrigerant. Next, after evacuating the atmospheric gas, the storage cylinder was heated to -70°C.
It was agglomerated into a storage bomb by cooling to 50°C and conversely heating the trap layer to 50°C. Mo obtained at this time
F6 was 180g.

The exhaust gas that went through the film forming process or the exhaust gas that came out of the trap after the cleaning process was removed in the same manner as in Example 1. Example 3 ReF6 was used as a raw material gas, hydrogen gas was mixed with this gas so that ReF6:H2 (molar ratio) = 1:7, and the mixture was introduced into a CVD apparatus.

The CVD apparatus was the same as in Example 1 except that a graphite substrate was used. The total flow rate was set at 1 L/min, the furnace temperature was set at 500° C., and the reaction was carried out at a pressure of 20 Torr for 3 hours to obtain a Re plate-like body of 30×30×0.3 mm.

When the inside of the tubular furnace was observed when the plate-shaped body was taken out, it was found that film-like substances and powdery substances were deposited on the surface. After taking out the plate and sealing the tubular furnace again, it is evacuated, and the inside of the system is replaced with nitrogen gas. After evacuating, a mixed gas of fluorine gas (400 cc/min) and nitrogen gas (1.6 L/min) is added. introduced as
Cleaning treatment was performed at 300°C.

The cleaned gas was introduced into a fluoride recovery device, and ReF6 was coagulated and solidified in a trap filled with a 0° C. refrigerant. Next, after evacuating the atmospheric gas, the storage cylinder was similarly cooled to -70°C, and conversely, the trap layer was heated to 70°C to cause agglomeration in the storage cylinder. ReF obtained at this time
6 was 220g.

The exhaust gas that went through the film forming process or the exhaust gas that came out of the trap after the cleaning process was removed in the same manner as in Example 1. Example 4 WF6 was used as a raw material gas, benzene and hydrogen were added to this gas, and the mixture was mixed so that the molar ratio of WF6:benzene:hydrogen was 2:1:30, and the mixture was introduced into a CVD apparatus.

The CVD apparatus is the same as in Example 1. The total flow rate was 2.5L/min, and the furnace temperature was 500℃.
℃, the reaction was carried out for 3 hours, and 0.00% was placed on the nickel substrate.
A 6 mm WC film was obtained.

When the inside of the tube furnace was observed when the substrate was taken out, it was found that film-like substances and powdery substances were deposited on the surface. After taking out the plate and sealing the tubular furnace again, it is evacuated, and the inside of the system is replaced with nitrogen gas. After evacuating, a mixed gas of fluorine gas (400 cc/min) and nitrogen gas (1.6 L/min) is added. introduced as 3
Cleaning treatment was performed at 00°C.

The cleaned gas was introduced into a fluoride recovery device, and WF6 was coagulated and solidified in a trap filled with a 0° C. refrigerant. Next, after evacuating the atmospheric gas, the storage cylinder was heated to -70°C.
It was agglomerated in a storage bomb by cooling to 70°C and conversely heating the trap layer to 70°C. WF obtained at this time
6 was 280g.

The exhaust gas that went through the film forming process or the exhaust gas that came out of the trap after the cleaning process was removed in the same manner as in Example 1.

[0041]

Effect of the invention: By using the device of the present invention, C
It is possible to clean unnecessary deposits that have accumulated in the pipes connected to the VD device and exhaust gas abatement device, and the obtained fluoride can be used again as raw material gas, making it extremely economical and efficient. It is capable of performing CVD work.

[Brief explanation of drawings]

FIG. 1 shows a conceptual diagram of an example of a film forming apparatus equipped with a deposit collection apparatus of the present invention.

Claims (1)

[Claims] 1. A cleaning apparatus for forming a film of a metal or its compound by a CVD method using a metal fluoride as a raw material, which comprises a raw material gas supply device, a CVD device, an exhaust gas removal device, and further has piping connected to the CVD device. A film forming apparatus equipped with a deposit recovery device, characterized in that it is equipped with a gas supply device and a fluoride recovery and supply device.