JP2010147118A - Method for suppressing surface corrosion in semiconductor manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for effectively suppressing surface corrosion when apparatuses of a semiconductor manufacturing device are subjected to the action of a compound gas containing a fluorine atom and a chlorine atom. <P>SOLUTION: A compound gas containing a fluorine atom and a chlorine atom is introduced into a processing chamber of a semiconductor manufacturing device and an inside of piping communicating with the processing chamber to perform cleaning or processing. Then, a purge gas including an inert gas with a dew point temperature of 213 K or below is introduced into the processing chamber and the piping communicating with the processing chamber. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for suppressing internal corrosion of a processing chamber and a gas pipe line in a semiconductor manufacturing apparatus such as a semiconductor element manufacturing apparatus, a semiconductor substrate manufacturing apparatus, a liquid crystal manufacturing apparatus, or a solar cell manufacturing apparatus, and particularly as a cleaning gas or an etching gas. The present invention relates to a method for suppressing surface corrosion of a processing chamber and a gas pipeline when a compound gas containing chlorine atoms and fluorine atoms is used.

Conventionally, in processing chambers and gas pipelines in semiconductor manufacturing devices such as semiconductor element manufacturing devices, semiconductor substrate manufacturing devices, liquid crystal manufacturing devices, solar cell manufacturing devices, etc., at least one of chlorine atoms and fluorine atoms in these devices. After introducing a gas containing atoms and performing a cleaning process, a purge gas made of hydrogen gas or a hydrogen-containing compound is circulated to remove contaminants generated by the cleaning process.
Japanese Patent Laid-Open No. 1-152274 JP-A-2-190472

  Furthermore, what uses inert gas, such as nitrogen gas, as purge gas is proposed.

  However, if the purge gas is circulated after cleaning with a halogen-based cleaning gas such as chlorine trifluoride, there is a problem that the surface of the cleaning process is corroded more than necessary due to the influence of the cleaning gas remaining in the processing chamber and the gas piping. there were.

  This invention pays attention to such a point, and it aims at providing the method of suppressing surface corrosion effectively.

  In order to achieve the above object, the present invention provides a cleaning process or process by introducing a compound gas containing chlorine atoms and fluorine atoms into the inside of a processing chamber of a semiconductor manufacturing apparatus and a pipe line communicating with the processing chamber. After the treatment, a purge gas composed of an inert gas having a dew point temperature of 213 K or less is introduced into the treatment chamber and a pipe line communicating with the treatment chamber.

  In the present invention, since an inert gas having a dew point temperature of 213 K or less is used as the purge gas, the fluorine gas component and chlorine gas remaining on the inner surface of the equipment consisting of the processing chamber and the piping connected to the processing chamber. Generation of corrosive substances due to contact between the components and water can be prevented as much as possible, and corrosivity due to fluorine gas components and chlorine gas components can be suppressed.

Hereinafter, the present invention will be described taking a CVD chamber of a semiconductor manufacturing apparatus as an example.
Usually, a CVD chamber used for manufacturing a semiconductor, a solar cell, a liquid crystal substrate, a photosensitive drum, etc. uses a halogen-based cleaning gas such as chlorine trifluoride (ClF ₃ ) after the thin film formation process. The deposits adhered to the inner surface and the substrate support surface are removed.

  After the cleaning process using the cleaning gas, a purge gas composed of an inert gas such as nitrogen gas is circulated in the chamber to remove the cleaning gas component from the chamber and prepare for the next thin film forming process. Yes.

  However, after the purge gas is circulated in the chamber, the metal surface in the chamber may be corroded. This is considered to be due to the fact that the corrosive force increases in the presence of moisture in the halogen-based gas.

From this point of view, in the present invention, the test piece of SUS304 is exposed to 100% ClF ₃ gas for 90 minutes, and then purged with nitrogen gas having a different dew point for 90 minutes, and the surface of the SUS304 test piece is subjected to fluorine (F). The concentration and chlorine (Cl) concentration were analyzed with an X-ray photoelectron spectrometer. The results are shown in Table 1 and FIG. In this case, the normalization assumes that the fluorine concentration and chlorine concentration at a dew point of −76 ° C. (197 K) for each element are 1.

As a result, it is understood that the fluorine concentration is not significantly affected by the dew point of the purge nitrogen gas until the dew point temperature is about −20 ° C. (253 K), but the chlorine concentration becomes higher as the dew point becomes higher (as the contained water concentration becomes higher).
Therefore, it can be seen that the corrosion by fluorine is almost constant regardless of the dew point, but the corrosion by chlorine appears more prominently as the dew point becomes higher.

Next, a 1 / 4-inch SUS316L electrolytic polishing tube, no welded part, and a sample pipe with a length of 200 mm were exposed to 100% ClF ₃ gas under conditions of 0.05 MPaG, 120 ° C., and 2 days to obtain a pure 40 ° C. It was immersed in water for 20 hours, and the total amount of eluted metals of iron, chromium, nickel, molybdenum and manganese was analyzed for the water. The relationship between the dew point temperature and the total amount of eluted metal is shown in Table 2 and FIG.

As a result, it can be seen that with ClF ₃ gas, the amount of eluted metal increases rapidly as the dew point temperature increases.

Further, after exposing a 1/4 inch SUS316L electrolytic polishing tube, no welded portion, and a 200 mm long sample pipe with 15% F ₂ gas diluted with helium at 0.35 MPaG, 60 ° C. for 6 days, The total amount of eluted metal was analyzed in the same manner as the ClF ₃ gas. The relationship between the dew point temperature and the total amount of eluted metal is shown in Table 3 and FIG.

As a result, in F ₂ gas, it can be seen that the difference in dew point temperature has little effect on the change in the amount of eluted metal.

Furthermore, after exposing 100% Cl ₂ gas at 0.35 MPaG, 60 ° C., 6 days to a 1/2 inch SUS316L electrolytic polishing pipe, one welded part by automatic welding, and a sample pipe having a length of 100 mm, Similar to the ClF ₃ gas and F ₂ gas, the total amount of eluted metal was analyzed. The relationship between the dew point temperature and the total amount of eluted metal is shown in Table 4 and FIG.

As a result, it can be seen that, in the Cl ₂ gas, the difference in dew point temperature greatly affects the fluctuation of the total eluted metal amount.

As described above, it can be confirmed that the amount of corrosion of the metal surface with which the cleaning gas comes into contact can be suppressed by reducing the moisture content of the purge gas used for the purge process after the cleaning process using the ClF ₃ gas. It was. In this case, the amount of eluted metal can be suppressed to 50 ppm or less by setting the dew point temperature of the purge gas to 213 K (−60 ° C.) or less corresponding to a moisture concentration of 10 ppm.

In the above embodiment, nitrogen gas is described as an example of the purge gas. However, the purge gas may be a rare gas such as helium or argon. Furthermore, the present invention can be applied to the case where ClF ₃ gas is used as an etching gas for the substrate.

  The present invention can be widely used as a method for suppressing internal corrosion in processing chambers and gas pipelines of semiconductor manufacturing apparatuses such as semiconductor element manufacturing apparatuses, semiconductor substrate manufacturing apparatuses, liquid crystal manufacturing apparatuses, and solar cell manufacturing apparatuses.

After treatment with ClF ₃ gas, the fluorine residual concentration in the purge gas dew point temperature and the metal surface of the case, purged with nitrogen gas, it is a graph showing the relationship between the chlorine residual concentration. ClF ₃ is a graph showing the relationship between dew point temperature and the elution concentration of metal when treated with gas. Is a graph showing the relationship between dew point temperature and the elution concentration of metal when treated with F _2. Is a graph showing the relationship between dew point temperature and the elution concentration of metal when treated with Cl _2.

Claims (3)

  After introducing a compound gas containing chlorine atoms and fluorine atoms into a processing chamber of a semiconductor manufacturing apparatus and a piping path communicating with the processing chamber and cleaning or processing the piping, the processing chamber and piping communicating with the processing chamber A method for suppressing surface corrosion in a semiconductor manufacturing apparatus, wherein a purge gas composed of an inert gas having a dew point temperature of 213 K or less is introduced into a road.   2. The method for suppressing surface corrosion in a semiconductor manufacturing apparatus according to claim 1, wherein the purge gas is nitrogen gas.   The method for suppressing surface corrosion in a semiconductor manufacturing apparatus according to claim 1, wherein the purge gas is a rare gas.

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