KR20170112523A - Plasma generator for gas abatement - Google Patents

Abstract

The present invention relates to a plasma generator for gas reduction. A plasma generator for gas abatement of the present invention is a plasma generator for gas abatement, comprising: a plasma source for providing ionization energy for forming a plasma; And ion accelerating means comprising at least one permanent magnet or induction magnet for providing energy to form a second ion acceleration direction in a direction different from the first ion acceleration direction formed by said ionization energy, . According to the plasma generator for reducing the gas of the present invention, it is possible to increase the residence time in the plasma channel by changing the motion locus of the reactive gas ions, thereby improving the gas decomposition rate. It is possible to maximize the plasma discharge efficiency in comparison with the same power supply. In addition, it is possible to prevent recombination of decomposed ions after the plasma is discharged, so that the plasma state can be maintained and supplied continuously.

Description

PLASMA GENERATOR FOR GAS ABATEMENT BACKGROUND OF THE INVENTION Field of the Invention [0001]

The present invention relates to a plasma generator for reducing gas, and more particularly, to a plasma generator for reducing gas for improving gas decomposition efficiency.

Plasma discharges are used in gas excitation to generate active gases including ions, free radicals, atoms, and molecules. Active gases are widely used in various fields and are typically used in a variety of semiconductor manufacturing processes such as etching, deposition, cleaning, and ashing.

In semiconductor processes such as etching and chemical vacuum deposition, chemical reaction gases may be used during processing or as a result of processing. In particular, perfluorocompounds (PFCs) are used in etching and cleaning processes using plasma during semiconductor / display processes. Their usage has also been increasing steadily with the expansion of the semiconductor / display market. PFCs used in the semiconductor / display process include CF4, CHF3, C2F6, C3F8, C4F8, NF3, and SF6. These perfluorocarbons are categorized as representative of global warming gases, and are subject to environmental regulations when perfluorocarbons are discharged into the air without being exhausted 100% from the chamber after processing. Therefore, it is preferable to discharge these gases to the air after decomposition.

In addition, when the chemical reaction gas discharged after the semiconductor process is discharged, the exhaust pipe is corroded and the vacuum pump is damaged, thereby shortening the life of the vacuum pump.

Currently, methods for treating PFCs discharged from a semiconductor / display process include plasma, chemical filtration, catalysis, pyrolysis, and incineration. Burn & Wet type scrubber, which uses heat and liquid, is widely used in the semiconductor field. However, in case of using high temperature for decomposition of perfluorocarbon, another regulated target NOx is generated and the temperature is lowered The decomposition efficiency of perfluorocarbon is lowered.

The PFC treatment method by plasma is small in size, simple to install, and easy to control the operating parameters. The method of using plasma for treating PFCs can be divided into a normal-pressure thermal plasma installed at the rear of the vacuum pump and a low-pressure glow plasma installed at the front of the vacuum pump, depending on the installation position of the plasma reactor. The atmospheric thermal plasma method is a method in which PFCs are pyrolyzed by using an arc discharge at a temperature of several thousand K or more, and is partially adopted in domestic semiconductor processes. However, the atmospheric pressure treatment method has an excellent advantage in terms of the decomposition rate due to the high temperature of the thermal plasma, but has a weak point in energy efficiency, which is equivalent to the power consumed per unit g, as compared with other treatment methods. This is because it is difficult to obtain a bulky plasma at normal pressure and efficient heat transfer is difficult with the process gas and power is wasted because it decomposes nitrogen, which is a purifying gas used in a vacuum pump, together with the process gas. On the other hand, in the low-pressure plasma method, it is possible to avoid a waste of energy consumed in the heating of nitrogen, which is a purifying gas, by decomposing / treating the PFCs at the front end of the vacuum pump, and to easily obtain a bulky plasma, Respectively. In addition, the low-pressure plasma method can control the size of the particles generated in the etching process and the chemical species of the byproducts, so that the vacuum pump has a function to dramatically increase the life of the vacuum pump.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a plasma generator for reducing a gas, which can improve the decomposition rate of a reaction gas by changing the ion trajectory of the reaction gas inside the plasma generator to increase the residence time of the reaction gas.

According to an aspect of the present invention, there is provided a plasma generator for reducing gas. A plasma generator for gas abatement of the present invention is a plasma generator for gas abatement, comprising: a plasma source for providing ionization energy for forming a plasma; And ion accelerating means comprising at least one permanent magnet or induction magnet for providing energy to form a second ion acceleration direction in a direction different from the first ion acceleration direction formed by said ionization energy, .

In one embodiment, the plasma source comprises a toroidal plasma chamber in which an annular plasma is formed; A power transformer having a primary winding coupled to the ferrite core and one or more ferrite cores mounted such that a portion of the plasma chamber passes therethrough; And a power source for supplying power to the primary winding.

In one embodiment, the induction magnet includes a magnetic core having a magnetic flux entrance so that a magnetic field can be formed in the plasma; And an induction coil wound around the magnetic core.

According to the plasma generator for reducing the gas of the present invention, it is possible to increase the residence time in the plasma channel by changing the motion locus of the reactive gas ions, thereby improving the gas decomposition rate. It is possible to maximize the plasma discharge efficiency in comparison with the same power supply. In addition, it is possible to prevent recombination of decomposed ions after the plasma is discharged, so that the plasma state can be maintained and supplied continuously.

1 is a view showing a concept of a plasma generator according to the present invention.
2 is a conceptual diagram showing a state in which a plasma generator according to a preferred embodiment of the present invention is installed in a process chamber.
3 is a view showing a first embodiment of the plasma generator equipped with the permanent magnet of the present invention.
4 and 5 are views showing various arrangement structures of the permanent magnets.
6 is a view showing a second embodiment of the plasma generator equipped with the permanent magnet of the present invention.
7 and 8 are views showing an embodiment of the plasma generator equipped with the induction magnet of the present invention.
9 is a view showing an ion motion locus at a portion where the induction magnet is mounted in the plasma generator.
10 is a view showing a state in which the power coil is wound on the induction magnet of the present invention.
11 is a view showing a third embodiment of the plasma generator equipped with the permanent magnet of the present invention.
12 is a view showing a cooling line of the plasma generator.
13 is an exploded perspective view of the plasma generator shown in Fig.
14 is a diagram showing a cross section of a plasma generator provided with permanent magnets.

For a better understanding of the present invention, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention may be modified into various forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below. The present embodiments are provided to enable those skilled in the art to more fully understand the present invention. Therefore, the shapes and the like of the elements in the drawings can be exaggeratedly expressed to emphasize a clearer description. It should be noted that the same components are denoted by the same reference numerals in the drawings. Detailed descriptions of well-known functions and constructions which may be unnecessarily obscured by the gist of the present invention are omitted.

1 is a view showing a concept of a plasma generator according to the present invention.

Referring to FIG. 1, a plasma generator according to the present invention includes a plasma source that provides ionization energy for generating a plasma 118. The first ion acceleration direction 142 is determined by the ionization energy provided from the plasma source. At this time, the ion acceleration means according to the present invention forms a second ion acceleration direction 144 in a direction different from the first ion acceleration direction 142 in the plasma 118. Therefore, the motion trajectory of the ions is changed by the first and second ion acceleration directions 142 and 144, and the rotational acceleration 146 is generated by a very complicated path. The rotation acceleration 146 increases the residence time of the ions in the plasma 118 and increases the ion decomposition rate.

2 is a conceptual diagram showing a state in which a plasma generator according to a preferred embodiment of the present invention is installed in a process chamber.

Referring to FIG. 2, a plasma generator 600 according to the present invention includes a plasma source and ion accelerating means for providing ionizing energy. The process chamber 195 may further include a remote plasma generator 50 for generating and supplying an active gas to the process chamber 195. The active gas accelerated by the ion accelerating means in the remote plasma generator 50 is supplied to the process chamber 195 connected through the adapter 190. The process chamber 195 is provided with a susceptor 196 on which the substrate 197 is placed and an exhaust pump 198 is connected to the exhaust port formed in the process chamber 195. Particularly, the plasma generator 100 according to the present invention is installed between the exhaust port 199 of the process chamber 195 and the exhaust pump 198 to decompose and discharge the exhaust gas discharged from the process chamber 195.

FIG. 3 is a view showing a first embodiment of the plasma generator equipped with the permanent magnet of the present invention, and FIGS. 4 and 5 are views showing various arrangement structures of the permanent magnets.

Referring to FIG. 3, a plasma generator 200 according to the present invention includes a plasma source for providing ionization energy and ion acceleration means. The active gas accelerated by the ion accelerating means in the plasma generator 200 is supplied to the process chamber 50 connected through the adapter. The process chamber 50 is provided with a susceptor 196 on which the substrate 197 is placed.

The plasma source provides ionization energy into the plasma chamber 210 such that a plasma 118 is generated within the plasma chamber 210. The plasma source is formed of any one of a capacitive coupled plasma, an inductively coupled plasma, and a transfer coupled plasma. The plasma source is composed of a plasma chamber 210 and a power transformer 220. The plasma chamber 210 includes a toroidal chamber body 212 in which an annular plasma 118 is formed. The chamber body 212 is formed separately from at least two. Above the chamber body 212, an ignition electrode (not shown) may be provided for initial ionization to ignite the plasma. The plasma chamber 210 has a gas inlet 114 connected to the process chamber 195 for receiving exhaust gas and a gas outlet 116 for discharging the gas decomposed in the plasma chamber 110 . The material of the plasma chamber 110 is formed of a conductor such as aluminum or formed of quartz. A cooling channel (not shown) is formed in the plasma chamber 110 to prevent the plasma chamber 110 from being overheated.

The power transformer 220 includes a ferrite core 222 and a primary winding 224. One or more ferrite cores 222 are mounted for passage through a portion of the plasma chamber 210 and a primary winding 224 is coupled to the ferrite core 222 and connected to a power source 202. The plasma 118 generated in the plasma chamber 210 forms the secondary side of the power transformer 220.

The ion acceleration means provides energy into the chamber body 112 to accelerate the ions in the plasma chamber 210. The ionization energy provided from the plasma source forms an annular first ion acceleration direction 142 in the chamber body 210. At this time, the second ion acceleration direction 144 is formed by the energy provided from the ion acceleration means. At this time, the first ion acceleration direction 142 and the second ion acceleration direction 144 are formed in directions different from each other. In other words, the second ion acceleration direction 144 is formed to have a predetermined angle (?> 0 과) with the first ion acceleration direction 142. In the present invention, since the first ion acceleration direction 142 and the second ion acceleration direction 144 are perpendicular to each other, the ions are rotated and the ion acceleration path becomes very complicated.

As the ion rotating means, a plurality of permanent magnets 230 may be used. The permanent magnet 230 is installed around the chamber body 212 of the plasma generator 290a or inserted into the chamber body 212. A magnetic field (a second ion acceleration direction) is formed in the chamber body 212 by providing the permanent magnets 230 having different polarities to be opposed to each other with respect to the plasma formed in the chamber body 212. The plurality of permanent magnets 230 are installed in a region of the chamber body 212 where the transformer 220 including the ferrite core 222 and the primary winding 224 is installed. The gas supplied to the interior of the chamber body 212 through the gas inlet 214 has a high rate of decomposition in the region of the chamber body 212 where the ferrite core 222 is installed. The reaction gas injected into the plasma chamber 210 is accelerated and moved by the first ion acceleration direction 142. At this time, the original motion locus is changed by the second ion acceleration direction 144, and the rotation acceleration 146 is performed while rotating. Therefore, the retention time of the rotated ions in the chamber body 212 is increased and the collision between the ions is easily generated by the rotation, so that the gas decomposition efficiency is increased and the plasma density is increased. Also, by providing a plurality of permanent magnets 230 in the region where the ferrite core 222 is installed, the acceleration path of the gas ions by the permanent magnets is complicated, and the decomposition rate is improved. The decomposed gas is discharged through the gas outlet 216.

A plurality of permanent magnets 230 may be installed around the insulation region of the chamber body 212. A magnetic field is formed in the insulating region by the plurality of permanent magnets 230, thereby rotating the gas ions passing through the insulating region to accelerate the ion acceleration path. Therefore, the residence time of the ions is increased, and it is possible to prevent the decomposed ions from being discharged in a state where they are recombined or not decomposed.

The chamber body 212 is preferably made of a material capable of inducing a magnetic field formed by the permanent magnet 230 into the chamber body 212. Here, the entire chamber body 212 may be made of a material capable of inducing a magnetic field inside thereof, or may be made of a material capable of inducing a magnetic field only in a region where the permanent magnet 230 is installed.

Referring to FIG. 4A, the plurality of permanent magnets 230 are installed such that the first and second permanent magnet modules 230a and 230b are opposed to each other. Here, the first and second permanent magnet modules 230a and 230b may be arranged in parallel so that the plurality of permanent magnets 230 face each other with different polarities. The first and second permanent magnet modules 230a and 230b are installed in the chamber body 212 so as to face each other with a different polarity to form a magnetic field.

Referring to FIG. 4 (b), the plurality of permanent magnets 230 are installed such that the first and second permanent magnet modules 230c and 230d face each other. Here, the first and second permanent magnet modules 230c and 230d may be arranged in parallel so that the plurality of permanent magnets 230 face the same polarity. The first and second permanent magnet modules 230a and 230b are installed in the chamber body 212 so as to face each other with a different polarity to form a magnetic field.

Referring to FIG. 5, a plurality of permanent magnets 230 may be installed in the chamber bodies 212a and 212b having various shapes such as a rectangular shape or a circular shape in cross section of the internal discharge space. The plurality of permanent magnets 230 may be inserted into the chamber bodies 212a and 212b or may be coupled to the chamber bodies 212a and 212b by a clamping member (not shown).

6 is a view showing a second embodiment of the plasma generator equipped with the permanent magnet of the present invention.

Referring to FIG. 6, the plasma generator 200a may be formed by providing a plurality of permanent magnets 230 as upper and lower portions of the chamber body 212 as ion rotating means. The chamber body 212 has a gas injection port 214 through which gas is injected and a gas discharge port 216 through which the decomposed gas is discharged. The plurality of permanent magnets 230 are installed so that the polarities of the permanent magnets 230 are opposite to each other with respect to the plasma 118 formed in the chamber body 212. Therefore, the gas injected into the gas injection port 214 is trapped in the chamber body 212 by the permanent magnet 230, so that the ion residence time is further increased, thereby increasing the ion decomposition rate. Also, the gas that has been moved to be discharged to the gas discharge port 216 is trapped in the chamber body 212 by the permanent magnet 230, so that the ion retention time is further increased, thereby increasing the ion decomposition rate.

The plurality of permanent magnets 230 may be installed only on one of the upper and lower portions of the chamber body 212. Further, it may be installed in a region where the ferrite core 222 is installed. As shown in FIG. 6 (b), a plurality of permanent magnets 230 may be disposed around the inner space of the chamber body 212.

FIGS. 7 and 8 are views showing an embodiment of a plasma generator equipped with an induction magnet according to the present invention, and FIG. 9 is a view showing an ion motion locus at a portion where the induction magnet is mounted in the plasma generator.

Referring to FIGS. 7 to 9, the plasma generator 300 is an ion acceleration means, and one or more induction magnet portions 350 are installed in the chamber body 312. The induction magnet section 350 includes a magnetic core 352 formed with a magnetic flux entrance and an induction coil 354 wound around the magnetic core 352. The induction coil 354 is connected to the induction magnet power supply source 351 and is supplied with driving power. Here, the induction coil 354 may be connected to a power source 302 connected to the primary winding 224 to receive power. The magnetic core 352 is mounted on the outside of the chamber body 312 such that the magnetic flux entrance 352 faces the inside of the chamber body 312. When the induction coil 354 is driven by the power supplied from the induction magnet power supply source 351, a magnetic field 358 formed between the magnetic flux entrance of the magnetic core 352 and the transformer 320 An electric field induced into the chamber body 312 is mixed. In other words, the electric field induced by the transformer into the chamber body 312 has a first ion acceleration direction, and the magnetic field 358 has another ion acceleration direction. Therefore, the gas ion path is complicated, the ion retention time is increased, and the ion decomposition rate is improved. The electric field induced by the magnetic core 352 has a second ion acceleration direction 358. [ Also, since the first ion acceleration direction is different from the second ion acceleration direction, the acceleration path of the ions is complicated, and the residence time of the ions is increased to improve the ion decomposition rate.

The induction magnet part 350 may be installed on the upper part of the chamber body 312. In particular, the induction magnet unit 350 may be installed at a portion where the chamber body 312 is formed in an annular shape. The gas injected into the gas injection port is distributed to both sides of the upper part of the chamber body 312 and linearly descends in the middle part where the ferrite core 322 is installed. ), The retention time of the ions is increased.

10 is a view showing a state in which the power coil is wound on the induction magnet of the present invention.

Referring to FIG. 10, the induction magnet unit 350 may be connected to the power coils 354a and 354b wound on the ferrite core 322. Power coils 354a and 354b wound on the ferrite core 322 are wound around the magnetic core 352 of the induction magnet unit 350 so that power supplied from the power source 302 to the primary winding 324 is supplied to the power coil 354a and 354b so that a magnetic field is formed at the magnetic flux entrance of the magnetic core 352. [ Here, the magnetic core 352 may be connected to one power coil or two power coils 354a and 354b.

Fig. 11 is a view showing a third embodiment of the plasma generator equipped with the permanent magnet of the present invention, Fig. 12 is a view showing a cooling line of the plasma generator, Fig. 13 is an exploded view of the plasma generator shown in Fig. It is a perspective view.

Referring to FIGS. 11 to 13, the plasma generator 600 of the present invention includes a plasma chamber 612 in which an annular plasma is generated. The plasma chamber 612 includes a gas inlet 614 into which an exhaust gas is injected, an upper chamber 612a in which a gas inlet 614 is installed, two tube chambers 612b having a straight discharge tube, a gas outlet 616, And a gas discharge port 616. The lower chamber 612c and the gas discharge port 616 are connected to each other. A ferrite core 622 is provided in the two tube chambers 612b, and a primary winding (not shown) is wound in the ferrite core 622. [ The tube chamber 612b may be provided with permanent magnets 630 as ion accelerating means for accelerating ions, respectively. After the permanent magnet 630 is installed, a cover 613 is provided to prevent the permanent magnet 630 from being exposed. Although the present invention discloses the plasma generator 600 having two tube chambers 612b, the number of the tube chambers 612b can be further increased.

As described above, the permanent magnet 630 forms a second ion acceleration direction in a direction different from the first ion acceleration direction formed by the plasma source, so that the acceleration path of the gas ions supplied into the plasma chamber 612 is complicated Thereby improving the decomposition rate.

Although not shown in the drawings, the induction magnet portion described above may be provided in the plasma generator 600 as an ion accelerating means to complicate the ion acceleration path. The induction magnet portion may be provided alone in the plasma generator, or may be provided together with the ion accelerating electrode portion or the permanent magnet.

The plasma chamber 612 is provided with a cooling channel 650. The cooling channel 650 is formed around the upper chamber 612a and the lower chamber 612b and is formed in the longitudinal direction of the tube chamber 612b. The cooling channel 650 is supplied with cooling water from a cooling water supply source (not shown), and the cooling water is circulated along the cooling channel 650 to prevent the plasma chamber 612 from overheating.

14 is a diagram showing a cross section of a plasma generator provided with permanent magnets.

Referring to FIG. 14, a plurality of permanent magnets 630 may be installed in the tube chamber 612b of the plasma chamber 612, as described above. The plurality of permanent magnets 630 are provided so as to face each other with a different polarity so that a magnetic field can be formed inside the tube chamber 612b by the permanent magnets 630 which are opposed to each other.

The embodiments of the plasma generator for reducing the gas of the present invention described above are merely illustrative and those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. .

Accordingly, it is to be understood that the present invention is not limited to the above-described embodiments. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims. It is also to be understood that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

210: plasma chamber 212, 312: chamber body
214, 314: gas inlet 216, 316: gas outlet
118: plasma 142: first ion acceleration direction
144: second ion acceleration direction 146: rotation acceleration
195: process chamber 196: susceptor
197: substrate to be processed 198: exhaust pump
200, 200a, 300: plasma generator 202, 302: main power source
220, 320: power transformer 222, 322: ferrite core
224, 324: primary windings 212a, 212b: second chamber body
230: permanent magnets 230a, 230b: first and second permanent magnet modules
350: Induction magnet section 351: Induction magnet power source
352: magnetic core 354: induction coil
354a: first power coil 354b: second power coil
356: magnetic field

Claims (3)

A plasma generator for gas abatement, the plasma generator comprising:
A plasma source for providing ionization energy to form a plasma; And
And ion accelerating means comprising one or more permanent magnets or induction magnets that provide energy to form a second ion acceleration direction in a direction different from the first ion acceleration direction formed by the ionization energy to change the motion trajectory of the ions And a plasma generator for reducing gas. The method according to claim 1,
The plasma source
A toroidal plasma chamber in which an annular plasma is formed;
A power transformer having a primary winding coupled to the ferrite core and one or more ferrite cores mounted such that a portion of the plasma chamber passes therethrough;
And a power supply for supplying power to the primary winding. ≪ Desc / Clms Page number 19 > The method according to claim 1,
The induction magnet
A magnetic core having a magnetic flux entrance port for forming a magnetic field in the plasma; And
And an induction coil wound around the magnetic core.

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