KR100772447B1 - Inductive coupled plasma source with built-in magnetic core - Google Patents

Abstract

An inductively coupled plasma source with a built-in magnetic core is disclosed. The plasma reactor of the present invention includes a reactor body that provides an annular plasma discharge chamber. Inside the plasma discharge chamber are refrigerated transformers with an annular magnetic core and primary windings that are built along the annular structure to provide a closed magnetic flux path. The magnetic core is covered and protected by the core protection tube as a whole so that its surface is not exposed to the plasma discharge chamber. The spokes extend from the sidewall of the plasma discharge chamber to the core protection tube. The core protection tube is connected by at least one spoke. The gas inlet and the gas outlet are symmetrically configured at the top and the bottom of the reactor body. The primary winding is electrically connected to a power source that supplies radio frequency power. The magnetic core is located in the inner plasma discharge chamber of the plasma reactor as a whole, so that the transfer efficiency of the inductive coupling energy coupled to the plasma is very high, thereby stably generating and maintaining a high density plasma. It is therefore suitable for a wide volume of plasma processing chambers provided for processing large workpieces.

Inductively Coupled Plasma, Plasma Treatment, Active Gas

Description

INDUCTIVE COUPLED PLASMA SOURCE WITH BUILT-IN MAGNETIC CORE}

In order to more fully understand the drawings used in the detailed description of the invention, a brief description of each drawing is provided.

1 is a perspective view of a plasma reactor according to a preferred embodiment of the present invention.

FIG. 2 is a partial cutaway perspective view of the plasma reactor of FIG. 1. FIG.

3 and 4 are vertical and horizontal cross-sectional views of the plasma reactor of FIG.

5 is a view showing the configuration of the ignition circuit of the plasma reactor.

6 is a cross-sectional view showing an e-gas outlet formed in the plasma reactor body along the annular structure of the plasma discharge chamber.

7 shows an example in which a plasma reactor is mounted in a process chamber.

* Description of the symbols for the main parts of the drawings *

10: plasma reactor 20: reactor body

30: transformer 40; Ignition electrode

60: process chamber 70: radio frequency generator

72: radio frequency cable

The present invention relates to a plasma source for generating an active gas containing ions, free radicals, atoms and molecules by plasma discharge and performing plasma treatment of solids, powders, and gases with the active gas. An inductively coupled plasma source having a core.

Plasma discharges are used for gas excitation to generate active gases containing ions, free radicals, atoms, molecules. The active gas is widely used in various fields and is typically used in various semiconductor manufacturing processes such as etching, deposition, and cleaning.

In recent years, wafers and LCD glass substrates for the manufacture of semiconductor devices are becoming larger. Therefore, there is a demand for a plasma source having a high controllability with respect to plasma ion energy and having a large-area processing capacity.

There are a number of plasma sources for generating plasma, such as capacitively coupled plasma using radio frequency and inductively coupled plasma. Among them, inductively coupled plasma sources are known to be suitable for obtaining high-density plasma because they can increase ion density relatively easily with increasing radio frequency power.

However, the inductively coupled plasma method uses a very high voltage driving coil because the energy coupled to the plasma is lower than that of the supplied energy. Thus, the high ion energy causes the inner surface of the plasma reactor to be damaged by ion bombardment. Damage to the internal surface of the plasma reactor by ion bombardment not only shortens the lifetime of the plasma reactor, but also has negative consequences of acting as a plasma treatment contaminant. When the ion energy is to be lowered, the energy bound to the plasma is low, so that frequent plasma discharge is turned off. Therefore, a problem arises that it is difficult to maintain stable plasma.

On the other hand, the use of remote plasma in the process using the plasma in the semiconductor manufacturing process is known to be very useful. For example, it is usefully used in cleaning process chambers and ashing processes for photoresist strips. However, as the size of the substrate to be processed increases, the volume of the process chamber is also increasing, and a plasma source capable of sufficiently remotely supplying high density active gas is required. This is especially true for multiple processing chambers that process multiple substrates simultaneously.

Accordingly, an object of the present invention is to provide an inductively coupled plasma source having a built-in magnetic core capable of stably maintaining a plasma and stably obtaining a high-density plasma by increasing the transfer efficiency of inductively coupled energy coupled to the plasma.

One aspect of the present invention for achieving the above technical problem relates to an inductively coupled plasma source. An inductively coupled plasma source of the present invention comprises: a reactor body providing an annular plasma discharge chamber; A transformer having an annular magnetic core and a primary winding provided inside the plasma discharge chamber along an annular structure to provide a closed magnetic flux path; A core protection tube that wraps and protects the annular magnetic core from being exposed to the plasma discharge chamber; One or more spokes extending from the sidewalls of the plasma discharge chamber to the core protection tube; And a power supply electrically connected to the primary winding, the current of the primary winding being driven by the power supply, wherein the driving current of the primary winding forms an inductively coupled plasma that completes the secondary circuit of the transformer. An inductively coupled plasma is formed in the annular plasma discharge chamber to surround the outside of the core protection tube along the center of the annular magnetic core.

In one embodiment, a gas inlet for injecting gas into the plasma discharge chamber and a gas outlet for discharging the plasma gas generated in the plasma discharge chamber, and have two gas flow paths divided between the gas inlet and the gas outlet. The plasma discharge chamber is arranged.

In one embodiment, there is provided a gas inlet for injecting gas into the plasma discharge chamber and a gas outlet for discharging the plasma gas generated in the plasma discharge chamber, the gas outlet being returned to the reactor body along the annular structure of the plasma discharge chamber. It is formed into a body shape.

In one embodiment, an ignition circuit having an ignition induction coil wound around an annular magnetic core and an ignition electrode electrically connected to the induction coil and installed in the plasma discharge chamber.

In one embodiment, the core protective tube comprises a dielectric material.

In one embodiment, the core protection tube comprises a metal material, and the metal material includes one or more electrically insulating regions to have electrical discontinuities in the metal material to minimize eddy currents.

In one embodiment, the reactor body comprises a metal material and the metal material includes one or more electrically insulating regions to have electrical discontinuities in the metal material to minimize eddy currents.

In one embodiment, a cooling water supply channel is installed inward of the core protection tube.

In one embodiment, a cooling water supply channel is formed through a central portion of the magnetic core.

In one embodiment, an impedance matching circuit is configured between the power supply and the primary winding to perform impedance matching.

In one embodiment, the power supply operates without an adjustable matching circuit.

In one embodiment, it further comprises a process chamber for receiving and receiving the plasma gas generated in the plasma discharge chamber.

In one embodiment, the reactor body has a structure that can be mounted in a process chamber, the power source has a structure that is physically separate from the reactor body, and the power source and the reactor body are remotely connected with a connecting cable.

In one embodiment, the gas flowing into the plasma discharge chamber is selected from the group comprising an inert gas, a reactive gas, and a mixed gas of an inert gas and a reactive gas.

DETAILED DESCRIPTION In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the embodiments of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings. In understanding the drawings, it should be noted that like parts are intended to be represented by the same reference numerals as much as possible. And detailed description of known functions and configurations that are determined to unnecessarily obscure the subject matter of the present invention is omitted.

(Example)

Hereinafter, an inductively coupled plasma source having a built-in magnetic core of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view of a plasma reactor according to a preferred embodiment of the present invention, Figure 2 is a partial cutaway perspective view of the plasma reactor of FIG.

1 and 2, the plasma reactor 10 according to a preferred embodiment of the present invention includes a reactor body 20 that provides an annular plasma discharge chamber 25. Inside the plasma discharge chamber 25, a transformer 30 having an annular magnetic core 31 and a primary winding 32, which is built along the annular structure and provides a closed magnetic flux path, is refrigerated. The magnetic core 31 is covered and protected by the core protection tube 26 as a whole so that the surface thereof is not exposed to the plasma discharge chamber 25. The magnetic core 131 is made of ferrite material but may be composed of other alternative materials such as iron and air. The gas inlet 21 and the gas outlet 22 are symmetrically configured at the top and bottom of the reactor body 20.

The reactor body 20 is made of a metal material, for example metal material such as aluminum, stainless steel, copper. Or coated metal, for example anodized aluminum or nickel plated aluminum. Or refractory metal. Alternatively, it is possible to rewrite the reactor body 110 with an insulating material such as quartz, ceramic, or other materials suitable for carrying out the intended plasma process. If the reactor body 20 comprises a metallic material, it includes one or more electrically insulating regions 24 that have electrical discontinuities in the metallic material to minimize eddy currents.

The core protection tube 26 is made of a dielectric material such as quartz, ceramic. Alternatively, the core protection tube 26 may be made of the same metal material as the reactor body 20, as described above, in which case it includes one or more electrically insulating regions to have electrical discontinuities to prevent eddy currents.

3 and 4 are vertical and horizontal cross-sectional views of the plasma reactor of FIG.

3 and 4, the spokes 27 extend from the sidewall of the plasma discharge chamber 25 to the core protection tube 26. The core protection tube 26 is connected by at least one spoke 27. The spokes 27 form through holes 23, through which the straight windings 32 are led and used as passages for supplying cooling water.

Although not illustrated in detail, a cooling water supply channel may be formed inside the core protection tube 26. Alternatively, the cooling water supply channel may be formed through the center of the magnetic core 31. Alternatively, both schemes may be employed. Alternatively, it is possible to form a coolant channel to surround the outside of the reactor body 20.

The primary winding 32 is electrically connected to a power source 33 that supplies radio frequency power. The electric current of the primary winding 32 is driven by the power supply 33, and the driving current of the primary winding 32 forms an inductively coupled plasma 34 which completes the secondary circuit of the transformer 30. Induces the inner AC potential. Thus, the inductively coupled plasma 34 is formed in the annular plasma discharge chamber 25 so as to surround the outside of the core protection tube 26 along the center of the annular magnetic core.

The gas flowing into the plasma discharge chamber 25 is selected from the group containing an inert gas, a reactive gas, and a mixed gas of the inert gas and the reactive gas. Or other gases suitable for other plasma processes may be selected.

The power supply 33 is configured using an RF power supply capable of controlling the output voltage without a separate impedance matcher. Alternatively, it can be configured using an RF power source that consists of a separate impedance matcher.

5 is a view showing the configuration of the ignition circuit of the plasma reactor.

Referring to FIG. 5, an ignition electrode 40 is configured in the internal plasma discharge chamber 25 of the reactor body 20. The ignition electrode 40 is electrically connected to an ignition induction coil 41 wound around the magnetic core 31. When a high voltage pulse is applied from the power supply source 33 to the primary winding 32 at the initial stage of the plasma discharge, a high voltage is induced to the ignition induction coil 41 to discharge between the ignition electrodes 40 to perform plasma ignition. After the ignition step, the electrical connection between the ignition electrode 40 and the ignition induction coil 41 may be cut off so that it does not function as an electrode. Alternatively, the electrical connection of the ignition electrode 42 may be maintained without interruption even after the ignition step.

In the inductively coupled plasma source of the present invention as described above, the magnetic core 31 is generally located in the inner plasma discharge chamber 25 of the plasma reactor 10, so that the transfer efficiency of the inductively coupled energy coupled to the plasma is very high. The plasma can be generated and maintained stably. It is therefore suitable for a wide volume of plasma processing chambers provided for processing large workpieces. Or a plasma processing chamber for simultaneously processing a plurality of substrates to be processed.

6 is a cross-sectional view showing an e-gas outlet formed in the plasma reactor body along the annular structure of the plasma discharge chamber.

Referring to FIG. 6, the reactor body 20 of the plasma reactor 10 according to one variation is installed horizontally, and the gas outlets 50 are formed along the annular structure of the plasma discharge chamber 25. Can be. Or it may consist of an opening of an annular structure as a whole along the annular structure. Such a gas outlet 50 may be usefully used to provide a large and uniform plasma of a large area in a plasma process having a large volume.

7 shows an example in which a plasma reactor is mounted in a process chamber.

Referring to FIG. 7, the plasma reactor 10 is mounted in the process chamber 60 to supply plasma to the process chamber 60 remotely. For example, it may be mounted outside the ceiling of the process chamber 60. The plasma reactor 10 receives a radio frequency from a radio frequency generator 70 which is a power source and receives gas by a gas supply system (not shown) to generate an active gas.

The process chamber 60 receives an active gas generated in the plasma reactor 10 and performs a predetermined plasma treatment. The process chamber 60 may be, for example, a deposition chamber performing a deposition process or an etching chamber performing an etching process. Or an ashing chamber for stripping the photoresist. In addition, it may be a plasma processing chamber for performing various semiconductor manufacturing processes.

In particular, the plasma reactor 10 and the radio frequency generator 70 as a power supply source for supplying radio frequencies have a separate structure. That is, the plasma reactor 10 is configured to be mounted to the process chamber 60, and the radio frequency generator 70 is configured to be separated from the plasma reactor 10. The output terminal of the radio frequency generator 70 and the radio frequency input terminal of the plasma reactor 10 are remotely connected to each other by a radio frequency cable 72. Therefore, unlike the conventional radio frequency generator and the plasma reactor is composed of a single unit it can be installed very easily in the process chamber 60 and can improve the maintenance efficiency of the system.

As described above, the present invention has been described with reference to the embodiments shown in the drawings, but this is merely exemplary, and those skilled in the art to which the present invention pertains have various modifications and equivalent embodiments. You can see that it is possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

According to the inductively coupled plasma source having a built-in magnetic core of the present invention as described above, the magnetic core is located in the inner plasma discharge chamber of the plasma reactor as a whole, the transfer efficiency of the inductively coupled energy coupled to the plasma is very high, so that the high density plasma It can keep generating stably. It is therefore suitable for a wide volume of plasma processing chambers provided for processing large workpieces. Or a plasma processing chamber for simultaneously processing a plurality of substrates to be processed.

Claims (14)

A reactor body providing a ring-shaped plasma discharge chamber; A transformer having an annular magnetic core and a primary winding provided inside the plasma discharge chamber along an annular structure to provide a closed magnetic flux path; A core protection tube that wraps and protects the annular magnetic core from being exposed to the plasma discharge chamber; An ignition electrode installed in the plasma discharge chamber; One or more spokes extending from the sidewalls of the plasma discharge chamber to the core protection tube; And A power source electrically connected to the primary winding, The current source of the primary winding is driven by the power source, and the driving current of the primary winding induces an AC potential inside the plasma discharge chamber which forms an inductively coupled plasma that completes the secondary circuit of the transformer, The inductively coupled plasma source is formed in the annular plasma discharge chamber to surround the outside of the core protection tube along the center of the annular magnetic core. delete delete 2. The inductively coupled plasma source of claim 1 comprising an induction coil for ignition wound around an annular magnetic core and electrically connected to the ignition electrode. The inductively coupled plasma source of claim 1, wherein the core protection tube comprises a dielectric material. The inductively coupled plasma source of claim 1, wherein the core protection tube comprises a metal material and the metal material includes one or more electrically insulating regions to have electrical discontinuities in the metal material to minimize eddy currents. 7. The induction according to claim 5, wherein the reactor body comprises a metallic material and the metallic material comprises at least one electrically insulating region which makes the electrical discontinuity in the metallic material to minimize eddy currents. Combined plasma source. The inductively coupled plasma source of claim 1 comprising a coolant supply channel installed inwardly of the core protection tube. The inductively coupled plasma source of claim 1 comprising a coolant supply channel formed through a central portion of the magnetic core. 2. The inductively coupled plasma source of claim 1 comprising an impedance matching circuit configured between the power supply and the primary winding to perform impedance matching. delete delete The method of claim 1, wherein the reactor body has a structure that can be mounted in the process chamber, the power source is a structure that is physically separated from the reactor body, An inductively coupled plasma source in which the power source and the reactor body are connected remotely by connecting cables. delete

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