JP2002057144A - Method and device for plasma processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processing device for decomposing PFC gas of high greenhouse effect coefficient to gas of low greenhouse effect coefficient and exhausting it to the air. SOLUTION: The plasma processing device has a sample processing chamber 1 for processing a sample, a major exhaust pump 3 for exhausting processing gas connected to the processing chamber and an exhaust means of a roughing pump 6 which is subjected to piping and connection to an exhaust port of the major exhaust pump 3. It also has an exhaust gas processing chamber 5 which decomposes, reacts, and polymerizes or removes gas exhausted from the major pump through discharge between a major exhaust pump and a roughing pump.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus for processing PFC gas discharged from a semiconductor manufacturing apparatus or the like.

[0002]

2. Description of the Related Art In recent years, various environmental changes are occurring on the earth, and these are considered to be caused by global warming in particular. Therefore, it is said that urgent measures such as reduction of the emitted carbon dioxide are necessary. PFC gas has a very high global warming potential and, if discharged into the atmosphere, causes deterioration of the global environment. For this reason, the world is in the direction of restricting PFC gas emissions.

In a semiconductor manufacturing process, a PFC gas is used for an etching gas in etching and cleaning of a CVD apparatus or the like. The gas discharged from the semiconductor manufacturing apparatus is adsorbed and removed by a sorbent such as activated carbon and discharged to the atmosphere.

However, unreacted PF contained in exhaust gas
C gas is not sufficiently removed by the adsorbent because it is chemically stable. Therefore, the PFC gas that has not been removed by adsorption is
It is released into the atmosphere as a gas with a high global warming potential.

[0005] As a measure against PFC gas emission, PFC
There is a method of thermally decomposing gas. However, it cannot be decomposed unless the temperature is raised, and there is a problem in safety.

[0006]

Most of the PFC gas used in the semiconductor manufacturing process is discharged to the atmosphere without reacting as described above, and the unreacted PFC gas is chemically stable. It is not decomposed by the adsorption removal process, and is discharged into the atmosphere as a gas having a high global warming potential.

The plasma sub-processing chamber disclosed in Japanese Patent Publication No. Hei 7-22151 does not decompose, react, polymerize or remove PFC gas because it is an etching monitoring method.

In the plasma processing apparatus, when checking the operation of the system and adjusting the pressure before the discharge,
The unreacted raw gas is discharged as it is, and there is a problem that such raw gas cannot be processed by an exhaust gas processing facility (a processing chamber containing an adsorbent or a small scrubber) provided at a subsequent stage.

An object of the present invention is to provide a plasma processing method and a plasma processing apparatus for converting a PFC gas into a gas having a low global warming potential and discharging the gas into the atmosphere.

[0010]

According to the present invention, there is provided a plasma processing apparatus, comprising: a sample processing chamber for processing a sample;
A main exhaust pump (for example, TMP: turbo molecular pump) connected to the processing chamber and provided for discharging gas generated in the processing, and connected to an exhaust port of the main exhaust pump by a pipe. A roughing pump (for example, a dry pump) is provided, and an exhaust gas processing chamber for discharging, discharging, decomposing, reacting, polymerizing, or removing gas discharged from the main pump between the main exhaust pump and the roughing pump is provided. Features.

In addition, the apparatus has a detector for detecting undecomposed PFC gas, and further decomposes, reacts, polymerizes or removes unreacted PFC gas.

Further, a plasma is generated by a direct current glow, an RF parallel plate type, a microwave or an inductive coupling, and Si or quartz is installed in a plasma processing chamber and reacted with PFC gas decomposed by the plasma. It is.

In the plasma processing chamber of the present invention, at least one of a case where plasma is not generated in the sample processing chamber and a case where PFC gas is supplied can be selected.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of the overall configuration of the plasma processing apparatus.

The first processing chamber 1 processes a sample. A process gas is introduced into the first processing chamber 1 from a gas introduction valve 2, and the process gas in the first processing chamber 1 is exhausted by a main exhaust pump (TMP) 3.

The discharged gas is introduced into an exhaust gas treatment chamber 5 through a gas introduction valve 4, decomposed, reacted, polymerized or removed by plasma discharge, and then discharged by a roughing pump 6. The discharged gas is discharged to the atmosphere after removing harmful components in the adsorption tower 7.

FIG. 2 is a schematic sectional view of the exhaust gas processing chamber 5. In the exhaust gas processing chamber 5 of the present embodiment, plasma is generated using a parallel plate type plasma source.

The exhaust gas processing chamber 5 has an upper electrode 11 and a lower electrode 12 for converting the introduced PFC gas into plasma, a high frequency power supply 13, and silicon 14 which reacts with the decomposed gas.

PFC performed by the plasma processing apparatus shown in FIG.
A method for treating gas exhaust gas will be described. The PFC gas introduced into the exhaust gas treatment chamber 5 from the gas introduction valve 4 is turned into plasma by the upper electrode 11, the lower electrode 12, and the high-frequency power supply 13. The plasma-converted PFC gas reacts with the silicon 14 provided in the lower electrode 12. For example, P
NF ₃ which is FC gas reacts as in the following equation (1).

[0020]

Embedded image 3Si + 4NF ₃ → 2N ₂ + 3SiF ₄ (1) By the above reaction, NF ₃ gas having a high global warming coefficient is formed into SiF ₄ having a low global warming coefficient.

In the above embodiment, the plasma source of the exhaust gas treatment chamber 5 is of a parallel plate type, but the same effect can be obtained by using a DC glow, microwave or inductive coupling type source.

In the above embodiment, one exhaust gas treatment chamber 5 is shown, but by arranging a plurality of exhaust gas treatment chambers in series, the reaction efficiency can be further increased.

In the above-described embodiment, the exhaust gas processing chamber 5 can be selected only when plasma is not generated in the first processing chamber 1, or when PFC gas is supplied, or both. Can be.

In the above embodiment, the high frequency power supply 13 of the exhaust gas processing chamber 5 may be shared with the power supply of the first processing chamber 1. At this time, when flowing the gas, the gas was allowed to react in either one of them, and the dry pump was designed so that the discharged gas was always sucked.

FIG. 3 is a schematic diagram of the entire configuration provided with a PFC gas detector. The PFC gas contained in the gas exhausted from the exhaust gas treatment chamber 5 is detected by the detector 8 [for example, 4
Quadrupole mass spectrometer (QMS)]. Simultaneously with the detection by the detector 8, the second exhaust gas processing chamber 9 operates and the PFC
Decompose, react, polymerize or remove gas.

In the above, the gas can be re-introduced into the exhaust gas treatment chamber 5 by the detection by the detector to perform the re-treatment.

In the embodiment of the present invention, a PFC gas having a high global warming coefficient is subjected to plasma discharge treatment, whereby it can be decomposed into a gas having a low global warming coefficient and discharged to the atmosphere. Further, by performing the reprocessing using the detector, the emission of the PFC gas can be suppressed. Also,
By arranging a plurality of exhaust gas treatment chambers in series, P
Emission of FC gas can be further suppressed.

[0028]

The plasma discharge of a PFC gas having a high global warming coefficient can be decomposed and discharged into a gas having a low global warming coefficient, and the PFC gas can suppress atmospheric pollution.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of the entire configuration of an exhaust gas treatment device.

FIG. 2 is a schematic sectional view of an exhaust gas treatment chamber.

FIG. 3 is a schematic diagram of the entire configuration of an exhaust gas treatment device using a PFC gas detector.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st processing chamber, 2 ... gas introduction valve, 3 ... main exhaust pump, 4 ... gas introduction pump, 5 ... exhaust gas treatment chamber, 6 ... roughing pump, 7 ... adsorption tower, 8 ... detector, 9 ... 2. Exhaust gas treatment chamber, 11: upper electrode, 12: lower electrode, 13: high frequency power supply, 14: silicon.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 16/44 B01D 53/34 134C H05H 1/46 134E (72) Inventor Motohiko Yoshikai Nakagawa, Adachi-ku, Tokyo No. 13-17, Hitachi Techno Engineering Co., Ltd. (72) Inventor Yoshifumi Ogawa 794, Higashi-Toyoi, Kazamatsu-shi, Yamaguchi Prefecture F-term in the Kasado Plant of Hitachi, Ltd. 4D002 AA22 BA03 BA04 BA07 CA07 DA21 DA46 DA70 EA02 EA05 GA02 GB02 4G075 AA03 AA37 AA62 BA05 BD12 CA16 CA26 CA47 EB42 4K030 DA06 EA11 FA01 FA03 FA04 KA39 5F004 AA16 BC02 BC04

Claims (8)

[Claims] 1. A main processing unit comprising: a sample processing chamber for processing a sample; a main exhaust pump connected to the processing chamber for discharging a processing gas; and a roughing pump connected to an exhaust port of the main exhaust pump. A plasma processing apparatus having an exhaust gas processing chamber for decomposing, reacting, polymerizing or removing gas discharged from a gas between a main exhaust pump and a roughing pump. 2. The exhaust gas treatment chamber includes a direct current glow, RF
The plasma processing apparatus according to claim 1, wherein the plasma is generated by a parallel plate type, a microwave, or an inductive coupling. 3. The plasma processing apparatus according to claim 1, wherein the exhaust gas processing chamber is provided with Si or quartz that reacts with PFC gas decomposed by plasma in the chamber. 4. The exhaust gas treatment chamber according to claim 1, further comprising a detector for detecting a PFC gas in the gas discharged from the exhaust gas treatment chamber, wherein the detector can perform re-decomposition, reaction, polymerization, or removal in the exhaust gas treatment chamber. Plasma processing equipment. 5. The plasma discharge in the exhaust gas processing chamber may be configured to select at least one of a case where plasma is not generated in the sample processing chamber and a case where PFC gas is supplied. The plasma processing apparatus as described in the above. 6. An apparatus comprising a processing chamber for processing a sample, a main exhaust pump connected to the processing chamber for discharging a processing gas, and a roughing pump connected to an exhaust port of the main exhaust pump by piping. A plasma processing method comprising: discharging a gas discharged from the main exhaust pump between the main exhaust pump and a roughing pump to decompose, react, polymerize, or remove the processing gas. 7. The plasma processing method according to claim 6, wherein a PFC gas is detected from the decomposed processing gas by a PFC gas detector. 8. The plasma processing method according to claim 7, wherein the detected unreacted gas in the PFC gas is further decomposed, reacted, polymerized, or removed.