JP2001048542A - Method for cleaning tantalum oxide production unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject method comprising heating at a specific temperature tantalum alkoxide decomposition/reaction products formed by the action of a fluoride gas and deposited on a tantalum oxide production unit equipped with a gas cleaning mechanism using CIF3 or the like, its pipings or the like to easily remove the above products. SOLUTION: This method for cleaning a unit intended for producing tantalum oxide using a tantalum alkoxide as raw material and equipped with a gas cleaning mechanism using CIF3, F2, NF3, CF3I or C2F5I comprises the following practice: tantalum alkoxide decomposition/reaction products formed by the action of the above fluoride gas and deposited on the production unit, its pipings or the like are heated at >=50 deg.C, pref. 50-200 deg.C in an N2 gas flow to decompose >=10 wt.% of the above products; alternatively, more effective cleaning can be accomplished by allowing a highly reactive gas such as of CIF3, F2, BrF3, BrF5, IF5 or IF7 to flow at a concentration of about >=0.001-10% while heating at 50-150 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing tantalum oxide using a tantalum alkoxide having a gas cleaning mechanism as a raw material, and a reaction between a tantalum alkoxide attached or deposited in a pipe connected to the apparatus and a cleaning gas. The present invention relates to a cleaning method for removing decomposition / reaction products.

[0002]

2. Description of the Related Art Tantalum oxide produced using tantalum alkoxide as a raw material by CVD has been used as a high dielectric material in industrial fields such as semiconductors. However, when producing tantalum oxide by this method, a solid-state film similar to tantalum oxide deposited mainly on a film-forming substrate is deposited on the inner wall of the reactor, and a low-temperature portion such as a pipe is Unreacted tantalum alkoxide is deposited.

[0003] When tantalum oxide in the reactor is thickly deposited, the tantalum oxide is separated from the adhering portion, causing particles in the reactor. When unreacted liquid tantalum alkoxide is deposited in the piping, it diffuses into the gas phase, It forms nuclei and becomes a factor for generating particles. Therefore, they must be cleaned.

[0004] As a current method for removing these deposits, C
Plasma rescreening using a highly reactive fluoride gas such as 1F ₃ and F ₂ and plasma cleaning using NF ₃ , CF ₃ I, C ₂ F ₅ I and the like are performed.

[0005] However, these methods have the following problems. That is, when the cleaning gas such as ClF ₃ or F _{2 at} a high concentration comes into contact with unreacted pentaethoxytantalum, there is a risk of ignition, so that the concentration of the high reactive gas flowing into the exhaust pipe is constant or constant pressure. It is necessary to keep the following (JP-A-9-301718). Under these circumstances, pentaethoxytantalum which has absorbed fluoride and its decomposed products, and fluoride which has been absorbed by pentaethoxytantalum, especially after the vacuum pump exposed to the atmosphere, undergo hydrolysis. TaO which is an organic liquid or solid having high viscosity and an inorganic reaction product (solid) of pentaethoxy tantalum and fluoride gas
Comprising a mixture of ₂ F. This mixture generates an acid gas and poses a danger to work safety. Further, when the mixture is washed with water, hydrofluoric acid is generated in water, which is dangerous.

[0006]

As a result of intensive studies, the present inventors have found that the above-mentioned fluorinated decomposition / reaction product is heated, or is heated and allowed to act on ClF ₃ , F ₂ or the like. They found that they could be cleaned and arrived at the present invention.

That is, the present invention relates to ClF ₃ , F ₂ , NF
_In an apparatus for producing tantalum oxide using tantalum alkoxide as a raw material, which is provided with a gas cleaning mechanism using ₃ , CF ₃ I or C ₂ F ₅ I, decomposition / reaction of tantalum alkoxide deposited on the apparatus / pipe with a fluoride gas Heating the product to 50 ° C. or above, or 50 ° C.
Heated as above, ClF ₃ , F ₂ , BrF ₃ , BrF ₅ , IF
_5, or is to provide a cleaning method of a tantalum oxide manufacturing apparatus characterized by reacting an IF _7.

In the present invention, the above-mentioned fluorination decomposition
Cleaning can be performed by maintaining the reaction product at a temperature of 50 ° C. or higher and heating in a nitrogen stream, thereby reducing the frequency of cleaning pipes and reducing the number of dangerous cleaning operations. Further, by applying a highly reactive gas such as ClF ₃ or F ₂ to the fluorinated decomposition / reaction product while heating, cleaning can be performed more quickly than heating in a N ₂ gas stream. Here, the highly reactive gas is ClF
_{3, F 2, BrF 3,} BrF 5, refers to IF ₅ or IF _7,.

In the present invention, although the composition of the fluorinated decomposition / reaction product to be cleaned is not known, as described above, pentaethoxytantalum which has absorbed fluoride and its fluorinated decomposition product, pentane It is a fluoride or the like absorbed by ethoxy tantalum, which is hydrolyzed to a high viscosity organic liquid or solid, or TaO ₂ F which is an inorganic reaction product (solid) of pentaethoxy tantalum and fluoride gas. Mainly in mixtures. These decomposition / reaction products are decomposed by 10% or more by heating in a N ₂ stream. The heating temperature is preferably 50 ° C or higher, and particularly preferably a temperature range of 50 to 200 ° C. If the temperature is lower than 50 ° C., the cleaning does not proceed.
Cleaning reaches equilibrium at 0 ° C, and 200 ° C
, Cleaning hardly proceeds.

Further, in order to promote the cleaning, a highly reactive gas is circulated in the above temperature range. The gas concentration is preferably 10% or less and 0.001% or more. Even if the gas concentration is 10% or more, the cleaning effect does not change much, and the amount of gas used increases, which is not economical. On the other hand, if the content is 0.001% or less, the cleaning speed becomes low, which is not preferable. However, when flowing a highly reactive gas, if the temperature exceeds 150 ° C., the metal pipe itself is corroded by reaction with the gas, which is not preferable.

The pressure is not particularly limited as long as the flowing gas and the waste gas are discharged out of the system.

[0012]

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

[0013] Examples 1-4, Comparative Example _{1 Ta (OC 2 H 5)} 5 was performed to repeat the process for cleaning the work and the reactor for depositing a Ta ₂ O ₅ and pyrolyzed at ClF ₃ device The black deposit deposited on the exhaust port of the vacuum pump was collected and heated in an N ₂ stream at atmospheric pressure to measure the weight loss. The results are shown in Table 1. The inorganic substance contained in the black deposit was found to be TaO ₂ F as a result of X-ray diffraction analysis.

[0014]

[Table 1]

[0015] Example 5-12, Comparative Example _{2 Ta (OC 2 H 5)} 5 was performed to repeat the process for cleaning the work and the reactor for depositing a Ta ₂ O ₅ and pyrolyzed at ClF ₃ device The black deposit deposited on the exhaust port of the vacuum pump was sampled, heated in a stream of ClF ₃ diluted with N ₂ at atmospheric pressure, and the weight loss was measured. The results are shown in Table 2. The inorganic matter contained in the black deposit is X
As a result of a line diffraction analysis, it was TaO ₂ F.

[0016]

[Table 2]

Example 13 An exhaust port of a vacuum pump of an apparatus in which the operation of thermally decomposing Ta (OC ₂ H ₅ ) ₅ to form a film of Ta ₂ O ₅ and the operation of cleaning the reactor with ClF ₃ were repeated. the deposited black deposits were collected, diluted to 0.1% under atmospheric pressure N ₂ was F ₂
The weight loss was measured by heating to 100 ° C. for 20 hours in an air stream. As a result, a weight reduction effect of 56 wt% was obtained.
The inorganic substance contained in the black deposit was found to be TaO ₂ F as a result of X-ray diffraction analysis.

[0018]

According to the method of the present invention, it is possible to easily remove the decomposition / reaction products caused by the reaction between the cleaning gas and the tantalum alkoxide attached or deposited in the tantalum oxide producing apparatus and the pipe connected to the apparatus.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Tadayuki Kawashima 2805 Imafukunakadai, Kawagoe City, Saitama Prefecture Inside the Chemical Research Laboratory (72) Inventor Tetsuya Tamura 2805 Imafukunakadai, Kawagoe City, Saitama Prefecture Central Glass F-term in Chemical Research Institute Co., Ltd. (reference) 3B116 AA13 AB53 BB82 CC05 4G048 AA02 AB01 AB03 AC02 AD02 AE08 4K030 AA02 AA04 BA42 CA02 DA03 JA10 5F058 BC03 BF03 BF27 BH20

Claims (2)

[Claims] 1. An apparatus for producing tantalum oxide from a tantalum alkoxide provided with a gas cleaning mechanism using ClF ₃ , F ₂ , NF ₃ , CF ₃ I or C ₂ F ₅ I. A method for cleaning a tantalum oxide producing apparatus, comprising heating a decomposition / reaction product of a deposited tantalum alkoxide by a fluoride gas to 50 ° C. or higher. 2. An apparatus for producing tantalum oxide from tantalum alkoxide having a gas cleaning mechanism using ClF ₃ , F ₂ , NF ₃ , CF ₃ I, or C ₂ F ₅ I as a raw material. The decomposition / reaction product of the deposited tantalum alkoxide by the fluoride gas is heated to 50 ° C. or more, and ClF ₃ , F ₂ , BrF ₃ , BrF ₅ , I
A method for cleaning a tantalum oxide manufacturing apparatus, comprising reacting with F ₅ or IF ₇ .