KR100805558B1 - Inductively coupled plasma source having multi discharging tube coupled with magnetic core - Google Patents

Abstract

An inductively coupled plasma source with multiple discharge tubes coupled to a magnetic core is disclosed. The plasma reactor has two plasma discharge tubes, each having independent plasma discharge chambers. A transformer is mounted to provide the inductive coupling energy for the plasma discharge to the plasma discharge tube. The transformer has an annular magnetic core that forms a closed loop and a primary winding wound thereon. The magnetic core is coupled to penetrate the center of the plasma discharge tube. The plasma discharge tube has a hollow cylindrical structure and has a common gas inlet at the top and a gas outlet at the bottom. Most of the magnetic core cross sections are located inside the plasma discharge chamber, so that the transfer efficiency of the inductive coupling energy coupled to the plasma is very high. Therefore, not only can the plasma be stably maintained, but also a high density plasma can be obtained. In addition, it has a repetitive expansion structure and can be very useful for providing a large area of plasma in a large volume plasma process.

Inductively Coupled Plasma, Plasma Treatment, Active Gas

Description

INDUCTIVELY COUPLED PLASMA SOURCE HAVING MULTI DISCHARGING TUBE COUPLED WITH 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.

2A and 2B are vertical and horizontal cross-sectional views of the plasma reactor of FIG. 1.

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

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

5 to 9 show various variations of the plasma reactor.

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

10: plasma reactor 20: plasma discharge tube

30: transformer 31: magnetic core

32: primary winding 33: power source

50: process chamber 60: radio frequency generator

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, and specifically, a magnetic core. An inductively coupled plasma source having multiple discharge tubes coupled thereto.

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, the present invention provides an inductively coupled plasma source having multiple discharge tubes coupled to a magnetic core that can stably maintain a plasma and stably obtain a high density plasma by increasing the transfer efficiency of inductively coupled energy coupled to the plasma. Its purpose is to.

One aspect of the present invention for achieving the above technical problem relates to an inductively coupled plasma source. Inductively coupled plasma sources of the present invention include: a transformer having a magnetic core and a primary winding; A plurality of plasma discharge tubes coupled to the magnetic core so as to penetrate the center, and separated to have independent discharge spaces; A core protection tube surrounding the magnetic core portion penetrating the plasma discharge tube; A power supply electrically connected to the primary winding, wherein the current is driven by the power supply and the driving current of the primary winding is inside the plasma discharge tube to form an inductively coupled plasma that completes the secondary circuit of the transformer. An inductively coupled plasma, which induces an AC potential, is formed in the plasma discharge tube so as to surround the outside of the core protection tube about the magnetic core portion passing through the plasma discharge chamber.

In one embodiment, there is a gas inlet for injecting gas into the plasma discharge tube and a gas outlet for discharging the plasma gas generated in the plasma discharge tube, wherein a plurality of plasma discharge tubes are parallel between the gas inlet and the gas outlet. Or connected in series.

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

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 plasma discharge tube includes 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, two or more separate multiple gas outlets are included.

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 tube.

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

In one embodiment, the gas entering the plasma discharge tube is selected from the group comprising an inert gas, a reactive gas, and a mixed gas of inert gas and 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, with reference to the accompanying drawings illustrating a preferred embodiment of the present invention, an inductively coupled plasma source having multiple discharge tubes coupled to the magnetic core of the present invention will be described in detail.

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

Referring to FIG. 1, the plasma reactor 10 includes two plasma discharge tubes 20 each having an independent plasma discharge chamber 24 (see FIG. 2). A transformer 30 is mounted to provide the inductive coupling energy for the plasma discharge to the plasma discharge tube 20. The transformer 30 has an annular magnetic core 31 and a primary winding 32 wound thereon, forming one closed loop. The magnetic core 31 is coupled to penetrate the center of the plasma discharge tube 20. The plasma discharge tube 20 has a hollow cylindrical structure and has a common gas inlet 21 at the top and a gas outlet 22 at the bottom.

The plasma discharge tube 20 is made of a metal material such as aluminum, stainless steel, or copper. Or can be rewritten with a coated metal, for example anodized aluminum or nickel plated aluminum. Or refractory metal. Alternatively, the plasma discharge tube 20 may be rebuilt from an insulating material, such as quartz or ceramic, and may be rebuilt from other materials suitable for the intended plasma process to be performed. If the plasma discharge tube 20 comprises a metal material, it includes one or more electrically insulating regions 26 to have electrical discontinuities in the metal material to minimize eddy currents.

2A and 2B are vertical and horizontal cross-sectional views of the plasma reactor of FIG. 1.

2A and 2B, the magnetic core portion penetrating the plasma discharge tube 20 is wrapped and protected by the core protection tube 23. The part where the core protection tube 23 and the plasma discharge tube 20 contact is vacuum-insulated by a suitable vacuum insulating member (not shown). The core protection tube 23 is made of a dielectric material such as quartz and ceramic. Alternatively, the core protection tube 23 may be made of the same metal material as the core protection tube 23 as described above, in which case one or more electrically insulating regions (not shown) have electrical discontinuities to prevent eddy currents. City).

Inside the core protection tube 23 is mounted a cooling water supply pipe 34 for forming a cooling water supply channel while surrounding the magnetic core 31. Alternatively, the cooling water supply channel may be formed through the center of the magnetic core 31. Alternatively, the cooling water supply channel may be formed at both the cooling water supply pipe 34 and the center of the magnetic core 31. Alternatively, the cooling water channel may be formed to surround the outside of the plasma discharge tube 20.

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.

The primary winding 32 is electrically connected to a power source 33 that supplies radio frequency power. The current in the primary winding 32 is driven by the power supply 33. The drive current of the primary winding 32 induces an AC potential inside the plasma discharge tube 20, which forms an inductively coupled plasma 35 that completes the secondary circuit of the transformer 30. The inductively coupled plasma 35 is then independent of the interior of the two plasma discharge tubes 20 so as to surround the outside of the core protection tube 34 about the magnetic core portion penetrating the plasma discharge chamber 24. Is formed.

The gas flowing into the plasma discharge chamber 24 is selected from the group containing an inert gas, a reaction gas, and a mixed gas of the inert gas and the reaction gas. Or other gases suitable for other plasma processes may be selected.

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

Referring to FIG. 3, ignition electrodes 42 are formed in the internal plasma discharge chamber 24 of the plasma discharge tube 20, respectively. The ignition electrode 42 is electrically connected to the induction coil 40 for ignition wound on 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 40 to discharge between the ignition electrodes 42 to perform plasma ignition. After the ignition step, the electrical connection between the ignition electrode 42 and the ignition induction coil 40 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 plasma reactor 10 is divided into two plasma discharge tubes 20, and the magnetic core 31 is disposed in the plasma discharge chamber 24 therein. The transfer efficiency of the inductive coupling energy coupled to the plasma is very high. In addition, the structure of the plasma reactor 10 described above has a structure that can be easily expanded in various forms, such as the modifications described below. 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.

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

Referring to FIG. 4, the plasma reactor 10 is mounted in the process chamber 50 to remotely supply plasma to the process chamber 50. For example, it may be mounted outside the ceiling of the process chamber 50. The plasma reactor 10 receives a radio frequency from a radio frequency generator 60 which is a power source, and receives gas by a gas supply system (not shown) to generate an active gas.

The process chamber 50 receives the active gas generated in the plasma reactor 10 and performs a predetermined plasma treatment. The process chamber 50 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 60 as a power supply source for supplying radio frequencies have a separate structure. That is, the plasma reactor 10 is configured to be fixed to the process chamber 50, and the radio frequency generator 60 is configured to be separated from the plasma reactor 10. The output terminal of the radio frequency generator 60 and the radio frequency input terminal of the plasma reactor 10 are remotely connected to each other by a radio frequency cable 61. 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.

The inductively coupled plasma source of the present invention may be modified in various ways as described below. In the following modifications, the same components are denoted by the same reference numerals, and repeated descriptions are omitted.

5 to 9 show various variations of the plasma reactor.

In one variation, as shown in FIG. 5, the plasma reactor 10a has four plasma discharge tubes 20-1 to 20-4 arranged in a cubic shape, and a multi-loop magnetic type having a cubic shape to penetrate them. The core 31 is mounted. The magnetic core 31 may be composed of an assembly of a plurality of ferrite pieces. The gas inlet 21 and the gas outlet (not shown) are commonly installed at the top and the bottom.

In another variation, the plasma, plasma reactor 10b shown in FIG. 6 has three plasma discharge tubes 20-1-20-3 arranged in parallel and are suitable for passing through the magnetic core 31 of the multi-loop type. Is fitted. The plurality of gas inlets 21-1 and 21-2 and the gas outlets 22-1 and 22-2 may be separately configured at the top and the bottom thereof, respectively.

In another variation, as shown in FIG. 7, the plasma reactor 10c has a multiple loop suitable for four plasma discharge tubes 20-1-20-4 to be radially disposed about and penetrating them. The magnetic core 31 having a is mounted. The plurality of gas inlets 21-1 and 21-2 and the gas outlets 22-1 may be separately configured at the top and the bottom.

In another variant, as shown in FIGS. 8 and 9, the plasma reactor 10d has two plasma discharge tubes 20 arranged in parallel at the top and the bottom thereof, and are connected to each other by a connecting tube 27.

There will be many other variations in addition to the above modifications, but it will be appreciated that these modifications will be apparent to those skilled in the art based on the spirit of the present invention.

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 multiple discharge tubes coupled to the magnetic core of the present invention as described above, most of the magnetic core cross sections are located inside the plasma discharge chamber to transfer the inductive coupling energy coupled to the plasma. The efficiency is very high. Therefore, not only can the plasma be stably maintained, but also a high density plasma can be obtained. In addition, it has a repetitive expansion structure and can be very useful for providing a large area of plasma in a large volume plasma process.

Claims (14)

A plasma reactor including a transformer having a magnetic core and a primary winding, and a plurality of plasma discharge tubes coupled to the magnetic core to penetrate a central portion thereof, each separated to have independent discharge spaces; A core protection tube surrounding a portion of the magnetic core passing through the plasma discharge tube; A power supply electrically connected to the primary winding; And An ignition circuit having an ignition induction coil wound around the magnetic core and an ignition electrode electrically connected to the ignition induction coil and installed in the plasma discharge tube, A current of the primary winding is driven by the power supply source, and the driving current of the primary winding induces an AC potential inside the plurality of plasma discharge tubes to form an inductively coupled plasma which completes the secondary circuit of the transformer, And the inductively coupled plasma is formed to surround the outside of the core protection tube in an inner discharge space of the plurality of plasma discharge tubes. The method of claim 1, A gas inlet for injecting gas into the plurality of plasma discharge tubes and a gas outlet for discharging plasma gas generated in the plurality of plasma discharge tubes; The plurality of plasma discharge tubes connected in parallel or in series between the gas inlet and the gas outlet. delete The method of claim 1, And the core protection tube comprises a dielectric material. The method of claim 1, The core protective tube comprises a metallic material, And the metallic material comprises one or more electrically insulating regions to have electrical discontinuities in the metallic material to minimize eddy currents. The method according to any one of claims 4 to 5, The plurality of plasma discharge tubes comprises a metallic material, And the metallic material comprises one or more electrically insulating regions to have electrical discontinuities in the metallic material to minimize eddy currents. The method of claim 1, An inductively coupled plasma source comprising a coolant supply channel installed inwardly of the core protection tube. The method of claim 1, An inductively coupled plasma source comprising a coolant supply channel formed through a central portion of the magnetic core. The method of claim 2, The gas outlet comprises two or more separate multiple gas outlets. The method of claim 1, And an impedance matching circuit configured between the power supply and the primary winding to perform impedance matching. The method of claim 1, The power supply operates without an adjustable matching circuit. The method of claim 1, And a process chamber for receiving and receiving plasma gases generated from the plurality of plasma discharge tubes. The method of claim 12, wherein the plasma reactor has a structure that can be mounted in the process chamber, The power source has a structure physically separated from the plasma reactor, And the power source and the primary winding of the plasma reactor are remotely connected with a connecting cable. The method of claim 1, The gas flowing into the plurality of plasma discharge tubes is An inductively coupled plasma source selected from the group consisting of inert gases, reactive gases, mixed gases of inert gases and reactive gases.

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