KR100742659B1 - Inductively Coupled Plasma Generator Using Magnetic Core - Google Patents

Abstract

The present invention is a chamber for generating a plasma; A plurality of loop pipes are provided on the outside of the chamber at regular intervals, and form a loop to communicate the input and output with the chamber; A magnetic core completely surrounding each roof tube at a boundary between the roof tube and the chamber; And an antenna wound in series over the magnetic core to generate a magnetic field for inducing an electric field flowing through each loop.

Roof tube, inductively coupled plasma generator, magnetic core, high permeability

Description

Inductively coupled plasma generating apparatus with magnetic core

1 is a longitudinal sectional view of an inductively coupled plasma generating device according to an embodiment of the present invention.

2a to 2c is a cross-sectional view of the inductively coupled plasma generating apparatus according to an embodiment of the present invention.

3 is an enlarged view of a magnetic core part according to an embodiment of the present invention.

Figure 4 is an enlarged view of a magnetic core portion of another form according to an embodiment of the present invention.

5a and 5b is a magnetic core combination of the upper side according to an embodiment of the present invention.

Figure 6a is a longitudinal sectional view of the inductively coupled plasma generating apparatus according to another embodiment of the present invention.

Figure 6b is a cross-sectional view of the inductively coupled plasma generator according to another embodiment of the present invention.

*** Explanation of symbols for main parts of drawing ***

100: inductively coupled plasma generator 101: chamber

102: roof tube 103, 103-1, 103-2, 103 ', 103'-1, 203: magnetic core

104, 104-1, 204: antenna 105, 105-1, 205: upper antenna

106, 206: gas inlet 107, 207: exhaust port

108, 208: insulation plates 109, 209: chuck

110, 210: opening and closing 201: outer roof pipe

202: internal chamber 211: bridge

The present invention relates to an inductively coupled plasma generator, and more particularly, to an inductively coupled plasma generator that generates a uniform high density plasma on a large area using a high permeability core.

Plasma is used in a technical field in which a fine pattern is to be formed, such as in a semiconductor chip manufacturing process or a manufacturing process of a flat panel display device such as a plasma display panel (PDP), a liquid crystal display (LCD), an organic luminescence (EL), and the like. It is produced and subjected to various surface treatment processes such as physical vapor deposition (PVD) such as dry etching, chemical vapor deposition (CVD), sputtering. Recently, in order to reduce costs and improve yield, the size of the substrate tends to be large, for example, 300 mm or more, and accordingly, the size of the plasma generator for processing large diameter substrates is increasing.

Representative forms widely used in such plasma generators include, for example, an inductively coupled plasma generator and a capacitively coupled plasma generator, and the double inductively coupled plasma generator includes a chamber in which a plasma is generated. The chamber is provided with a gas inlet for supplying the reaction gas and a vacuum pump and a gas outlet for discharging the reaction gas after the reaction is maintained in a vacuum. In addition, a chuck for placing a sample such as a wafer or a glass substrate is provided inside the chamber, and an antenna to which a high frequency power source is connected is installed in the upper portion of the chamber. An insulating plate may be installed between the antenna and the chamber to transmit electromagnetic waves induced by the antenna, thereby transferring power from the antenna to the plasma.

In the conventional inductively coupled plasma generator, a single spiral antenna or a plurality of split-electrode antennas are used. As RF power is applied, a magnetic field that changes in time perpendicular to the plane of the antenna is formed. The changing magnetic field forms an induction electric field inside the chamber, and the induction electric field heats electrons to generate a plasma inductively coupled with the antenna. Thus, electrons collide with surrounding neutral gas particles to generate ions and radicals, and they are used for plasma etching and deposition.

However, in the antenna of the spiral structure, since the induction coils constituting the antenna are connected in series, the amount of current flowing in each induction coil becomes constant. In this case, it is difficult to control the distribution of the induction field. It is difficult to prevent the density of the plasma from being lowered in the central portion of the high density near the inner wall of the chamber. Therefore, it is extremely difficult to keep the density of the plasma uniform.

In addition, since each induction coil of the antenna is connected in series, the voltage drop by the antenna is increased, so the influence of capacitive coupling with the plasma is increased. Therefore, the power efficiency is lowered and it is also difficult to maintain the uniformity of the plasma.

Next, in the antenna having three split electrode structures connected to three high frequency power sources having different phases from each other, the plasma density is high at a position close to each split electrode, and the plasma density is lower at the center of the chamber, thereby ensuring uniformity of plasma. This is difficult, and it becomes particularly difficult to process a large area substrate. In addition, since the power must be used independently of each other to increase the cost, there is a problem that a separate impedance matching circuit must be used for each divided electrode for impedance matching for efficient use of the power.

On the other hand, the plasma generator has a problem that the plasma density distribution in the chamber is not uniform due to the structural cause of the loop antenna. That is, a region with a relatively high plasma density is formed in the middle of the antenna, and the plasma density at the power supply terminal and the ground terminal of the antenna is relatively low, and the plasma density distribution on the cross section cut along the diameter is relatively low. It was not symmetrical with each other and was nonuniform.

This is because the relatively high voltage is applied to the power supply side of the antenna, resulting in ion loss, which leads to a drop in plasma density. In addition, current flows between the disconnected part of the loop antenna, that is, the power supply and ground terminals. This is because there is no induction electric field, and plasma generation in this part is weakened, and thus a drop in plasma density occurs.

In order to solve this problem, in Korean Utility Model Publication No. 253559, a power end to which RF power is applied is formed at one end and the other end of the ground end is electrically grounded. Two looped antennas are installed in parallel, the powered and ground ends of each antenna are symmetrically positioned with respect to the center of the antenna, the powered and ground ends of each antenna are located far from the chamber and in the middle of each antenna The part provides an antenna structure of an inductively coupled plasma generator which generates a uniform plasma density in a rotational direction which is installed in parallel with each other so as to be close to the chamber.

However, in the plasma generating apparatus equipped with such an antenna structure, various problems occur. First, since the middle part of each antenna near the chamber crosses up and down, the height difference in the plane and the vertical direction formed by the antenna is different. As a result, a difference in electric field is generated, thereby inhibiting the uniformity of plasma generated in the chamber.

In addition, in order to improve the generation efficiency of the plasma generated in the chamber, a strong induction electric field should be formed, and for this purpose, the RF power supplied to the antenna has to be increased.

An object of the present invention is to provide an inductively coupled plasma generator capable of uniformly generating and distributing high density plasma therein in order to solve the above problems.

Another object of the present invention is to provide an inductively coupled plasma generator capable of forming a strong electric field inside the plasma generator.

Still another object of the present invention is to increase the power efficiency of an inductively coupled plasma generator by generating a high density plasma on a large area even at low internal pressure and low RF power.

The objects, features and advantages of the present invention will be more clearly understood from the embodiments described below.

A chamber generating a plasma to achieve the above object; A plurality of loop pipes are provided on the outside of the chamber at regular intervals, and form a loop to communicate the input and output with the chamber; A magnetic core completely surrounding each roof tube at a boundary between the roof tube and the chamber; And an antenna wound in series with the entire magnetic core to generate a magnetic field for inducing an electric field flowing through each loop.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a longitudinal cross-sectional view of an inductively coupled plasma generator according to an embodiment of the present invention, Figures 2a to 2c is a cross-sectional view of the inductively coupled plasma generator according to an embodiment of the present invention A-A 'of FIG. A cross section cut along the side.

1 and 2A to 2C, the inductively coupled plasma generator 100 includes a chamber 101, a loop tube 102 in which an electric field is induced, a magnetic core 103 for forming a magnetic field, and an RF. The power supply antenna 104, the upper antenna 105 mounted on the top of the chamber, the gas injection port 106 is injected gas, the exhaust port 107 for discharging the used gas, opening and closing the opening 110 It is composed of a chuck 109 provided for mounting inside the chamber through).

The roof tube 102 is circular or rectangular in cross section, and is circular in this embodiment, spaced apart at predetermined intervals along the circumferential direction of the chamber 101 and communicating from the inside of the chamber 101 to the inside of the chamber 101 again. It is a protruding cylindrical annulus that enters and is located outside the chamber 101 in one or more numbers. In addition, as illustrated in FIG. 1, a plurality of roof tubes 102 may be layered at a predetermined interval along the longitudinal direction of the chamber 101.

The magnetic core 103 is in the form of a circular ring that is detachably wrapped around each roof tube 102. The magnetic core 103 surrounds the roof tube 102 at the boundary between the roof tube 102 and the chamber 101, and is made of a ferromagnetic material such as ferrite. It is provided to induce a strong electric field (E) to the roof tube 102 using a large magnetic permeability of. Here, the magnetic core 103 is a material of high permeability, OP ferrite, Ba ferrite, Mn-Zn-based ferrite, Ni-Zn-based ferrite, Cu-Zn-based ferrite, permalloy, and sendest (sendust) It may be composed of any one.

The antenna 104 and the upper antenna 105 are composed of a power supply terminal (not shown) to which RF power of 300 V or less and a current of 10 A or less is applied at one end and a ground terminal (not shown) for grounding at the other end. . An antenna 104 may be supplied with a low frequency power source of several hundred kHz and an upper antenna 105 may be connected to a high frequency power source such as a 13.56 MHz power source to facilitate plasma generation and contribute to uniform plasma generation. Can be. In addition, the same power source may be connected to the antenna 104 and the upper antenna 105.

As shown in FIG. 3, the antenna 104 of this configuration winds two magnetic cores 103 and 103-1 adjacent to the outside of the chamber 101, that is, the two magnetic cores 103 and 103-1 are magnetic. After winding together from the bottom of the core 103 in a clockwise direction, the other two magnetic cores 103 'and 103'-1 spaced apart by a predetermined distance are reversely wound together from the bottom of the magnetic core 103'-1 in a counterclockwise direction. The arrangement of this series of antennas 104 comprises a pair of two magnetic cores 103 and 103-1 and two other magnetic cores 103 'and 103'-1 along the circumferential direction of the chamber 101, respectively. It is wound up and placed continuously.

In addition, the antenna 104 is continuously arranged to wind two magnetic cores 103 and 103-1 along the circumferential direction of the chamber 101 and surround the other two magnetic cores 103 'and 103'-1. Instead, the two magnetic cores 103 and 103-1 and the other two magnetic cores 103 'and 103'-1 may be separately wound and disposed.

The upper antenna 105 is mounted on the insulating plate 108 and forms a magnetic field B that changes in time perpendicular to the plane of the insulating plate 108 to induce an electric field inside the chamber 101.

A process of generating a strong electric field in the inductively coupled plasma generator 100 having such a configuration will be described with reference to FIG. 3.

3 is an enlarged view of a portion of a magnetic core according to an embodiment of the present invention, and includes a magnetic core 103 surrounding the roof tube 102 at a boundary portion between the roof tube 102 and the circular chamber, and the magnetic An antenna 104 is shown winding the core 103.

As RF power is applied to the antenna 104, the antenna 104 forms a strong magnetic field B in any direction that changes in time in two adjacent magnetic cores 103 and 103-1. That is, the two magnetic cores 103 and 103-1 have a magnetic field B having opposite directions, for example, a magnetic field in a clockwise direction that changes in time is formed in the magnetic core 103 on one side, and the magnetic cores adjacent to each other ( 103-1) forms a counterclockwise magnetic field that changes in time.

In addition, magnetic fields B having opposite directions are formed in the other two magnetic cores 103 'and 103'-1, and a magnetic field in a clockwise direction that changes in time is formed in the magnetic core 103' on one side, and the adjacent side is formed. The magnetic core 103'-1 has a counterclockwise magnetic field that changes in time.

The opposite magnetic field B, which changes in time, is formed on the two magnetic cores 103 and 103-1 and the other two magnetic cores 103 ′ and 103 ′-1, so that the loop tube 102 has a magnetic field. A circular electric field E is passed from the right opening tube on which the core 103 is mounted to the left opening tube on which the magnetic core 103'-1 is mounted.

This induction electric field E is circularly induced in each roof tube 102 as shown in FIG. 2A, and thus, the induction electric field E is applied to the gas in the chamber injected through the gas inlet 106. The energy is applied to generate a plasma in the chamber 101. In addition, when the winding directions of the antenna 104 winding the two magnetic cores 103 and 103-1 and the other two magnetic cores 103 'and 103'-1 are reversed, as shown in FIG. A circular electric field E is passed from the left aperture tube on which the 103'-1 is mounted to the right aperture tube on which the magnetic core 103 is mounted.

Optionally, the antenna 104 may wind the magnetic cores 103, 103-1, 103 ′ and 103 ′-1, respectively, to induce the electric field E in a predetermined direction as shown in FIG. 2C.

Here, the above-described magnetic core 103, 103-1, 103 ', 103'-1 is in the form of a circular ring, but as shown in Figure 4 the magnetic core 103-2 is the end of the roof tube 102 It may take the form of a square ring that encloses a square.

In this case, the antenna 104-1 is not disposed as described above, but is disposed in a form surrounding the intermediate core 103-3 to form a magnetic field B such as a paired vortex passing through the intermediate core 103-3. The magnetic field 103-2 is generated, and the electric field E is induced in the loop tube 102 by the magnetic field B.

Optionally, the inductively coupled plasma generating apparatus 100 according to one embodiment of the present invention of FIGS. 1 and 2 may be configured by using an upper antenna 105 mounted on an insulating plate 108 above the chamber 101. In order to induce an electric field in the upper part of 101, but in order to induce a stronger electric field, as shown in Figures 5a and 5b, a plurality of loop tubes 102 and such loop tubes on the insulating plate 108 above the chamber 101 Each of the plurality of magnetic cores 103-2 having the shape of a square ring surrounded by the antennas 105-1 and each of the antennas 102-1 is lattice-arranged with the same density or spaced at a predetermined distance along the circumferential direction. May be

Using the magnetic cores 103 and 103-1 provided in the inductively coupled plasma generator 100 according to the embodiment of the present invention configured as described above, a strong electric field E is induced in the chamber 101 with low RF power. The high density plasma is generated through the induced electric field (E).

In order to use such a high-density plasma with a large area of 300 mm or more, such as wafers, LCDs, organic ELs, etc., the size of the chamber must be larger and the electric field strength must be stronger. Thus, as shown in FIGS. 6A and 6B, an inductively coupled plasma generator according to another embodiment of the present invention may be implemented.

Hereinafter, an inductively coupled plasma generator 200 according to another embodiment of the present invention will be described.

6A is a longitudinal cross-sectional view of an inductively coupled plasma generator according to another embodiment of the present invention, and FIG. 6B is a cross-sectional view of an inductively coupled plasma generator according to another embodiment of the present invention, taken along line C-C 'of FIG. 6A. One cross section view.

6A and 6B, the inductively coupled plasma generator 200 has a circular inner chamber 202 and a circular loop spaced apart from the inner chamber 202 at a predetermined distance to surround the inner chamber 202. A plurality of bridges 211 arranged at regular intervals between the outer roof tube 201 and the inner chamber 202 such that the outer roof tube 201, the outer roof tube 201, and the inner chamber 202 communicate with each other, A magnetic core 203 for enclosing each bridge 211 and forming a magnetic field, an antenna 204 to which RF power is supplied, an upper antenna 205 mounted to an upper chamber, a gas injection hole 206 to inject gas, It consists of an exhaust port 207 for discharging the spent gas, and a chuck 209 provided for mounting the wafer or glass substrate into the inner chamber 202 through the opening and closing port 210.

The inductively coupled plasma generator 200 includes a plurality of bridges 211 communicating between the outer roof tube 201 and the inner chamber 202 spaced apart by a predetermined distance along the circumferential direction, and further provided with an outer roof tube ( A plurality may be arranged along the height direction between the 201 and the inner chamber 202.

Each of the bridges 211 arranged in this way is surrounded from the outside and the magnetic core 203 wound by the antenna 204 is used to induce an electric field E passing through each bridge 211.

The magnetic core 203 completely surrounds the bridge 211 from the outside, and may be any one selected from a circular ring, a cylinder, a square ring, and a square cylinder, and the material of the magnetic core 203 may be the aforementioned magnetic core. Like the material of (103), it is composed of any one of OP ferrite, Ba ferrite, Mn-Zn ferrite, Ni-Zn ferrite, Cu-Zn ferrite, permoloy, and sendast.

A strong magnetic field B that changes in time in the magnetic core 203 is formed by the antenna 204 winding the magnetic core 203, so that a large diameter strong cross the bridge 211 as shown in FIG. 6B. The electric field E is induced, so a large electric field E of a large area is induced along the circumference of the plasma generator 200.

Using the induced electric field (E) in this way to generate a high-density plasma in the inner chamber 202, it is transmitted through the opening and closing 210 to process the wafer or glass substrate placed on the chuck 209.

RF power applied to a conventional inductively coupled plasma generator can induce a stronger electric field in a large area in the inductively coupled plasma generator according to the present invention and generate a high density plasma using such a strong electric field.

Although the technical spirit of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiments are for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various implementations are possible within the scope of the technical idea of the present invention.

As described above, the present invention may induce a strong electric field using a material having a high permeability with a low RF power source, and generate a high density plasma using the strong electric field.

By producing plasma of high density uniformly over a large area and using plasma for a large diameter wafer or glass substrate, production yield can be improved.

Claims (8)

A chamber generating a plasma; A plurality of loop pipes are provided on the outside of the chamber at regular intervals, and form a loop to communicate the input and output with the chamber; A magnetic core completely surrounding each roof tube at a boundary between the roof tube and the chamber; And And an antenna wound in series over the entire magnetic core to generate a magnetic field for inducing an electric field flowing through the respective loops. The apparatus of claim 1, wherein the roof pipes are arranged in plural spaces spaced apart from each other in the circumferential direction outside the side surface of the chamber. 3. The inductively coupled plasma generator using a magnetic core according to claim 2, wherein the roof tubes are arranged in plural spaces spaced apart from each other in the height direction of the chamber. The inductively coupled plasma generator using a magnetic core according to claim 1 or 2, wherein a plurality of roof tubes are arranged at a uniform density on the top of the chamber. 2. The magnetic core of claim 1, wherein the magnetic core surrounds the loop tube at the boundary of the roof tube and the chamber, and the antenna winds up the adjacent magnetic core together surrounding the adjacent loop tube. Inductively coupled plasma generator using. A chamber generating a plasma; A roof tube spaced apart from the chamber by a predetermined distance to surround the chamber; A plurality of bridges arranged at regular intervals along the roof tube and the chamber so that the roof tube and the chamber communicate with each other; A magnetic core completely surrounding each bridge; And And an antenna wound around the magnetic core in series to generate a magnetic field for inducing an electric field flowing through the bridge and the loop tube. 7. The inductively coupled plasma generator using a magnetic core according to claim 6, wherein a plurality of roof tubes and corresponding bridges are arranged along a height direction of the chamber. 8. The inductively coupled plasma generator using a magnetic core according to claim 7, wherein the arranged loop tube is integrated as a whole in the height direction.

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