JPH09301718A - Method for cleaning tantalum oxide producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely and efficiently remove and clean unnecessary deposited material in a device for producing tantalum oxide by allowing tantalum oxide depositing on the inside of the device or tubes to react with a specified compd. thereby removing it. SOLUTION: The decomposed material or unreacted material of tantalum oxide or tantalum alkoxide depositing on the inside of the device or tubes is made to react with at least one kind of compd. selected from among F2 , ClF3 , BrF3 BrF5 IF5 and IF7 and removed. When F2 is used for the reaction, the F2 gas is controlled to 35Torr partial pressure. The partial pressure of the gas is controlled to 30Torr for ClF3 , 30Torr for BrF3 , 30Torr for BrF5 , 40Torr for IF5 , and <=40Torr for IF7 . Thus, ignition due to contact of tantalum oxide or its decomposed material with fluorine-based gas can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor of a tantalum oxide manufacturing apparatus, a jig of the apparatus, or a decomposition product of tantalum oxide and tantalum alkoxide attached or deposited in a pipe connected to the apparatus, a jig, It relates to a method for safely removing the piping itself without damaging it.

[0002]

2. Description of the Related Art Tantalum oxide produced by CVD using tantalum alkoxide as a raw material is used as a high dielectric material in industrial fields such as semiconductors. However, when attempting to produce tantalum oxide by this method, a solid film similar to tantalum oxide mainly deposited on the film-forming substrate is deposited on the inner wall of the reactor, and in the low temperature portion such as the pipe, tantalum alkoxides and its degradation product of unreacted (low-order polycondensate _{[(TaC x H y O z} ) n]) is deposited.

When the tantalum oxide in the reactor is thickly deposited, it peels off from the adhering portion and causes particles to be generated in the reactor, and when unreacted liquid tantalum alkoxide or low-order polycondensation product is deposited in the pipe, it is vapor Particles are generated due to nucleation due to diffusion of gaseous substances into the layer. Therefore, they must be cleaned.

As a current method of removing these deposits, a method of disassembling the apparatus, pipes, etc. and scraping them by human power, a wet cleaning method with a strong acid, and a method of removing them by a sandblast method are generally used. Further, within the reactor, plasma cleaning with NF ₃ gas is also performed. However, these methods require dismantling of equipment, dismantling of pipes, removal of jigs, and the like for cleaning, which requires a long working time and significantly impairs the availability of the CVD equipment. In the plasma cleaning with NF _3, the portion outside the plasma atmosphere cannot be cleaned, and the inside of the pipe cannot be cleaned. From the above, a method for safely and efficiently removing these deposits is desired.

[0005]

[Means for Solving the Problems] As a result of intensive studies by the present inventors, the strong fluorination ability of F ₂ and ClF _3, which was generally considered to cause a combustion reaction when contacted with alkoxides. The present invention has been accomplished by finding a method of safely and efficiently removing a substance having

That is, according to the present invention, in a device for producing tantalum oxide, decomposed products and unreacted products of tantalum oxide and tantalum alkoxide deposited inside the device, etc., and F
_{The present} invention provides a method for cleaning a tantalum oxide production apparatus, which comprises reacting and removing at least one of ₂ , ClF ₃ , BrF ₃ , BrF ₅ , IF ₅ , and IF ₇ .

[0007] In more detail, in the F ₂ F ₂ gas partial pressure 35 Torr, in the ClF ₃ 30 Torr,
₃₀ Torr for BrF _{3 and 3} for BrF ₅
It was found that if the gas partial pressures of 0 Torr, IF _{5 and} 40 Torr, and IF ₇ are maintained at 40 Torr or less, respectively, no ignition occurs due to contact between the tantalum alkoxide or its low-order condensation polymer and the fluorine-based gas. The invention has been reached.

The object of cleaning in the present invention is C
Ta deposited in the reactor of the VD device _TwoO_FiveAnd exhaust system piping
And the trap inside the trap installed between the pipe and the vacuum pump.
Unreacted tantalum alkoxide and low-order condensation polymer
It is.

Ta ₂ O ₅ deposited in the reactor is preferably cleaned at 200 ° C. or higher and 600 ° C. or lower. Two
If the cleaning is performed at a temperature of 00 ° C. or lower, a tantalum fluoride layer is formed on the surface of Ta ₂ O ₅ and hinders the progress of the reaction, so that the deposit cannot be completely gasified and removed. Also, 60
If the temperature exceeds 0 ° C, the materials used in the apparatus will be significantly corroded, and the inside of the reactor will be contaminated by corrosion products, which is not preferable. The pressure condition is preferably 0.1 Torr or more in terms of fluorine-based gas partial pressure in order to ensure a sufficient reaction rate. However, since the gas that has passed through the inside of the reactor also passes through the exhaust pipe, N ₂ at the outlet of the reactor when cleaning at a pressure below the above pressure, or at a pressure above the above pressure conditions, H
It is necessary to dilute with a gas such as e, Ar or dry air to the pressure range of the above-mentioned fluorine-based gas.

Next, unreacted Ta (OC) deposited in the exhaust system
The cleaning of ₂ H ₅ ) ₅ and its low-order polycondensate will be described. When unreacted Ta (OC ₂ H ₅ ) ₅ and its low-order polycondensate flow into the dry pump which is the exhaust device, it decomposes in the pump and becomes Ta ₂ O ₅ , which damages the rotor of the pump and Liquid or powdery substances accumulate in the exhaust duct leading up to the exhaust gas treatment device. Therefore, a trap was installed before the dry pump and unreacted Ta (OC ₂
It is preferable to collect H ₅ ) ₅ and its low-order polycondensation product. In this case, the temperature of the trap and exhaust system piping is
Corrosion of F ₂ , ClF _3, etc. and unreacted Ta (OC ₂ H ₅ ) ₅
Or considering the collection efficiency of the low-order polycondensation product, the piping should be at room temperature (14 ° C) or higher and 100 ° C or lower, and the trap should be 60
It is preferable to keep the temperature below 0 ° C., and it is preferable to perform cleaning within this temperature range. However, unreacted Ta
When (OC ₂ H ₅ ) ₅ and cleaning gas such as F ₂ come into contact with each other, T
A small amount of aO ₂ F may be generated as a reaction residue. T
When aO ₂ F is produced, it can be completely gasified by heating the trap temperature to 60 ° C. or higher.
In this case, the trap temperature may be appropriately determined in consideration of corrosion between the fluoride gas used and the trap material. For example, when stainless steel, which is used as a general material, is used as a trap material, F ₂ is 260 ° C. or lower, ClF ₃ , BrF ₃ , BrF ₅ , IF ₅ , IF ₇ is 200 or less.
It may be maintained at a temperature of ℃ or below. This is not the case when a highly corrosion-resistant material such as nickel or aluminum is used as the metal material. TaO ₂ F has no danger of igniting even when it comes into contact with a fluorine-based gas, so the pressure conditions may be appropriately determined.

If necessary, nitrogen is used as a diluting gas,
You may use inert gas, such as helium and argon.

[0012]

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 7 and Comparative Example 1 Pentaethoxy tantalum was added to a SUS316 watch glass.
0 g was taken and placed in a quartz tube. F ₂ diluted with nitrogen was passed through this tube under the conditions shown in Table 1,
The presence or absence of ignition was checked visually and the temperature was measured with a thermocouple with an Al protective tube whose tip was immersed in pentaethoxytantalum. The results are shown in Table 1.

[0014]

[Table 1]

Examples 8 to 12, Comparative Example 2 1 part of pentaethoxy tantalum was added to a watch glass made of SUS316.
0 g was taken and placed in a quartz tube. ClF ₃ diluted with nitrogen was circulated in this tube under the conditions shown in Table 2, and the presence or absence of ignition was visually confirmed, and the temperature was measured with a thermocouple with an Al protective tube whose tip was immersed in pentaethoxytantalum. . The results are shown in Table 2.

[0016]

[Table 2]

Examples 13 to 17, Comparative Example 3 1 part of pentaethoxy tantalum was added to a watch glass made of SUS316.
0 g was taken and placed in a quartz tube. BrF ₃ diluted with nitrogen was circulated in this tube under the conditions shown in Table 3, and the presence or absence of ignition was visually confirmed, and the temperature was measured by a thermocouple with an Al protective tube whose tip was immersed in pentaethoxytantalum. . The results are shown in Table 3.

[0018]

[Table 3]

Examples 18 to 22, Comparative Example 4 1 part of pentaethoxy tantalum was added to a watch glass made of SUS316.
0 g was taken and placed in a quartz tube. BrF ₅ diluted with nitrogen was circulated in the tube under the conditions shown in Table 4, and the presence or absence of ignition was visually confirmed, and the temperature was measured by a thermocouple with an Al protective tube whose tip was immersed in pentaethoxytantalum. . The results are shown in Table 4.

[0020]

[Table 4]

Examples 23 to 30, Comparative Example 5 1 part of pentaethoxy tantalum was added to a watch glass made of SUS316.
0 g was taken and placed in a quartz tube. IF ₅ diluted with nitrogen was circulated in this tube under the conditions shown in Table 5, and the presence or absence of ignition was visually confirmed, and the temperature was measured with a thermocouple with an Al protective tube whose tip was immersed in pentaethoxytantalum. . Table 5 shows the results.

[0022]

[Table 5]

Examples 31 to 38, Comparative Example 6 1 part of pentaethoxy tantalum was added to a watch glass made of SUS316.
0 g was taken and placed in a quartz tube. IF ₇ diluted with nitrogen was circulated in this tube under the conditions shown in Table 6, and the presence or absence of ignition was visually confirmed, and the temperature was measured by a thermocouple with an Al protective tube whose tip was immersed in pentaethoxytantalum. . The results are shown in Table 6.

[0024]

[Table 6]

Example 39 The inside of a CVD apparatus, in which pentaethoxytantalum and oxygen were mixed and Ta ₂ O ₅ was deposited on a glass substrate at 300 ° C., was disassembled and the inside was observed. Ta ₂ O ₅ was found on the inner wall of the reactor. Is about 1μ
m, unreacted Ta in the trap installed in the exhaust pipe
About 200 g of (OC ₂ H ₅ ) ₅ and its low-order polycondensation product were deposited. After performing the same operation, ClF ₃
And N ₂ mixed gas (system pressure: 10 Torr, ClF ₃ flow rate: 100 SCCM, N ₂ flow rate: 900 SCCM, reactor internal temperature: 250 ° C., exhaust pipe temperature: 60 ° C., time:
(1 hour) was introduced and cleaning was attempted. As a result, all the deposits in the reactor and the pipe could be removed. Also,
No rise in pipe temperature of the exhaust system occurred and no corrosion occurred.

Example 40 A Ta ₂ O ₅ film was deposited to a thickness of 10 μm on the inner wall of a chamber of an apparatus for forming a Ta ₂ O ₅ film on a glass substrate by reactive sputtering. This chamber was installed in a reaction tube made of Ni equipped with a heater and exposed to ClF ₃ (concentration 100%, pressure 10
Torr, temperature 250 ° C., flow rate: 1 SLM, time: 1 hour). When the inside of the chamber was observed after completion of the reaction, Ta ₂ O ₅ deposited on the inner wall was completely removed.

Example 41 Glass obtained by heating pentaethoxytantalum in a liquid state at 540 ° C.
Spray on the substrate, Ta_TwoO_FiveSolution inside the device
As a result of observing the inside of the body, Ta on the inner wall of the reactor was_TwoO_Five
Is about 10 μm, which is not reflected in the trap installed in the exhaust pipe.
O Ta (OC _TwoH_Five)_FiveAnd its low-order polycondensation product is about 25
0 g had accumulated. After performing the same operation on the device,
ClF_ThreeAnd N_TwoMixed gas (system pressure: 10 Torr, C
IF_ThreeFlow rate: 100 SCCM, N_TwoFlow rate: 900 SCC
M, reactor internal temperature: 300 ° C, exhaust pipe temperature: 60
℃, time: 3 hours) was introduced to try cleaning
By the way, all the deposits in the reactor and piping were removed.
Was. Moreover, the temperature of the exhaust pipe does not rise and corrosion does not occur.
It wasn't

[0028]

According to the method of the present invention, it is possible to safely and efficiently remove and clean unnecessary deposits such as tantalum oxide and tantalum alkoxide decomposition products attached to a tantalum oxide manufacturing apparatus.

Claims (2)

[Claims] 1. An apparatus for producing tantalum oxide, comprising:
The tantalum oxide deposited in the inside of the apparatus, the pipes, etc. is converted into F ₂ and C.
_{lF 3, BrF 3, BrF 5} , IF 5, the cleaning method of the tantalum oxide manufacturing apparatus characterized by removing by reacting at least one of IF _7. 2. An apparatus for producing tantalum oxide using tantalum alkoxide, wherein decomposed products and unreacted products of tantalum alkoxide deposited inside the apparatus, pipes and the like,
A method for cleaning a tantalum oxide production apparatus, which comprises reacting and removing at least one of F ₂ , ClF ₃ , BrF ₃ , BrF ₅ , IF ₅ , and IF ₇ .