KR100476902B1 - The Large-Area Plasma Antenna(LAPA) and The Plasma Source For Making Uniform Plasma - Google Patents

Abstract

The present invention relates to an inductively coupled large area plasma antenna and a plasma generating apparatus including the same, wherein the inductively coupled large area plasma antenna includes an inner coil and an outer coil, and one end of the inner coil and the outer coil has an inner portion. The plane formed by the coil and the plane formed by the outer coil are not connected to each other at the same position, the other end of the inner coil and the outer coil is connected to the power terminal, the connection portion and the power end of the inner coil and outer coil It has a structure located on the surface opposite each other. The inductively coupled large-area plasma antenna can control the size of the electric field induced in the reactor of the plasma generator in a space and generates a plasma that is uniformly distributed in the reactor by appropriately controlling the diffusion of the plasma generated therefrom. .

Description

Large Area Plasma Antenna (LAPA) and Uniformly Generated Plasma Antenna (LAPA) and The Plasma Source For Making Uniform Plasma}

The present invention relates to an inductively coupled large area plasma antenna used in a plasma generator and a plasma generator including the same.

Plasma generators include Helicon and microwave plasma sources using capacitively coupled plasma sources, inductively coupled plasma sources, and plasma waves. plasma source). Among them, inductively coupled plasma generators capable of forming high density plasma at low operating pressures are widely used.

FIG. 1 illustrates an inductively coupled plasma generator that is generally used. The inductively coupled plasma generator 1 reacts into a chamber 101 in which a plasma 106 is generated and into the chamber 101. A gas inlet 102 for supplying a gas, and a vacuum pump 103 for maintaining the inside of the chamber 101 in a vacuum and discharging the reaction gas when the reaction is terminated. A substrate holder 105 for mounting a substrate 104 (for example, a wafer) to be mounted is installed, and an antenna 107 to which an rf power source 109 is connected is installed above the chamber 101. . When power is added from the rf power source 109 with impedance matching 108 to the antenna 107, rf power, that is, rf potential and current, is applied to the antenna 107. The applied rf potential forms an electric field that changes with time in the vertical direction of the dielectric 110 separating the antenna 107, and the rf current flowing through the antenna 107 is a magnetic field in the internal space 111 of the reaction chamber 101. And the magnetic field creates an induction electric field. At this time, the reaction gas inside the chamber 101 obtains sufficient energy for ionization from the applied electric field and forms the plasma 106. The formed plasma 106 enters the substrate 104 installed in the substrate holder 105 by another rf power source 112 applying a negative DC bias voltage to process the substrate 104.

On the other hand, the plasma 106 formed in the chamber 101 is more dense by the induced electric field by the magnetic field than the electric field formed in the chamber 101. Such a plasma is called an inductively coupled plasma and such equipment is called an inductively coupled type. It is called a plasma generator or a plasma generator. This plasma generator has the advantage of being able to form a high density plasma at low operating pressure.

FIG. 2 illustrates a planar spiral antenna which has been widely used in the plasma generator. In the planar spiral antenna, electromagnetic waves are largely formed at the center, and thus, the density distribution of the inductively coupled plasma generated is not uniform in space, and the density is high at the center and decreases toward the edge of the reactor. Therefore, in order to process a large area substrate of 300 mm or more, it is required to form a plasma having a uniform distribution in a space corresponding to at least the substrate area, but the aforementioned flat spiral antenna does not satisfy such a condition. have.

To solve this problem, various types of antennas have been disclosed. For example, Korean Patent Application No. 7010807/2000 discloses a transformer coupled balanced antenna in which the planar spiral antennas are arranged in parallel (see FIG. 3), and Korean Patent Application No. 14578/1998 forms a radiation structure. A large area planar antenna is disclosed (see FIG. 4). In addition, Korean Patent Application No. 35702/1999 discloses an antenna combined in a parallel form (see FIG. 5). However, the problem of operating this kind of antenna is that it is difficult to match the antenna and the input power, and the sculpted antennas are a problem due to the disturbance of electromagnetic waves generated between the antennas, manufacturing difficulties, and some of the antenna combinations when driving for a long time If the characteristics of the antenna are changed independently, there is a problem in the stability of the operation can not be adjusted. In addition, the parallel antenna is composed of several antenna coil wires. Therefore, in order to adjust the phase of the input current flowing through each parallel antenna line from the antenna input end to the output end, an inductor or a capacitor is independently attached to each line of the parallel antenna. This attachment condition also narrows the operating area of the reactor.

Therefore, the antenna using one input terminal and the other output terminal is the most ideal, and the antenna which can control the plasma density of the central part by controlling the formation of a large induced electric field in the central part generated from the spiral antenna Should be constructed.

Accordingly, an object of the present invention is to provide an antenna that can control the plasma density of the central portion by controlling the formation of a large induced electric field in the center portion generated in the planar spiral antenna. In other words, the present invention is to improve the problem of non-uniform distribution of the form of the plasma density of the central portion is a problem with the conventional planar spiral plasma, etc., and rapidly decreases toward the edge.

Another object of the present invention relates to a plasma generating apparatus having the above-described antenna.

The object of the present invention is to modify the shape of the antenna to control the current flow through the antenna to control the distribution of the electromagnetic field induced in the plasma generating device to generate a plasma having a uniform distribution in the generator and a structure capable of stable operation It can be achieved by providing an antenna having and a plasma generating device including the same.

The inductively coupled large area plasma antenna of the present invention for achieving the above object includes an inner coil and an outer coil, and one end of the inner coil and the outer coil has a plane formed by the inner coil and a plane formed by the outer coil. It is connected to each other at the same position, the other end of the inner coil and the outer coil is connected to the power terminal, the connecting portion and the power terminal of the inner coil and the outer coil has a structure located opposite to each other. More specifically, the inductively coupled large-area plasma antenna includes the inner coil, the outer coil, the auxiliary auxiliary coil, and the connecting coil, and one end of the inner coil and the outer coil has planar and outer coils formed by the inner coil. The other side of the inner coil and the outer coil is connected to each other by the connecting auxiliary coil and the connecting coil in a plane that is not the same as the plane to be formed, the power terminal is connected, the connecting portion (connection auxiliary coil and connecting coil) and the power stage Has a structure located on the opposite side.

The inductively coupled large area plasma antenna of the present invention having the structure as described above can control the size of the electric field induced in the reactor of the plasma generator in a space and by appropriately controlling the diffusion of the plasma generated therefrom within the reactor. Generate a plasma that is uniformly distributed. That is, the inductively coupled large-area plasma antenna according to the present invention is formed such that the direction of the current flowing through the inner coil and the current flowing through the outer coil have phases (180 °) in opposite directions to each other, and thus, in the inner coil and the outer coil. The generated electromagnetic field can be prevented from being largely formed at the center of the reactor, and by appropriately disposing the inner coil and the outer coil, a uniform electromagnetic field can be formed inside the reactor of the plasma generator, and further, the plasma is uniform inside the chamber. To be formed.

In addition, the inductively-coupled large-area plasma antenna of the present invention has a structural characteristic of smoothing the flow of cooling water because the inner coil and the outer coil are integrally connected.

The inductively coupled large area plasma antenna of the present invention can be configured in a variety of forms, including round, square (including rectangular and square) and elliptical. For example, both the inner coil and the outer coil may be configured in a circular, oval or square, the inner coil may be configured in a circular or oval shape, and the outer coil may be configured in a square or vice versa. In addition, the inner coil and the outer coil may be located on the same plane or, if necessary, on different planes. This will be described later with reference to the accompanying drawings.

6 is a schematic view of a preferred example of an inductively coupled large area plasma antenna according to the present invention, wherein the inductively coupled large area plasma antenna 2 includes an inner coil 201 and an outer coil 202. The inner coil 201 and the outer coil 202 are not closed, and the inner coil 201 is formed by the connection auxiliary coil 203 and the outer coil 202 is formed by the auxiliary coil 203. It is guided to a position away from and connected to each other by a connecting coil 204. Thus, the connecting portions 203 and 204 are not on the same plane formed by the inner coil 201 and the outer coil 202. The end 205 of the inner coil 201 is connected to an input terminal (or an output terminal), and the end 206 of the outer coil 202 is connected to an output terminal (or an input terminal). Therefore, the current i _in flowing in the inner coil 201 and the current i _ex flowing in the outer coil 202 flow in opposite directions to generate an electromagnetic field inside the reactor. In addition, the terminal connected to the end 205 of the inner coil 201, preferably secures the height corresponding to the connection coil 204 and the upper or outer coil 202 of the end 206 of the outer coil 202 ) Is passed over the closed area (dotted line 207) (208). In addition, the terminal connected to the end 206 of the outer coil 202, preferably, to secure the height corresponding to the connection coil 204 and to be connected to the outside of the antenna area made by the outer coil 202 (209). The inner coil 201 and the outer coil 202, the auxiliary auxiliary coil 203 and the connection coil 204 are composed of a conductor. The inner coil and the outer coil are configured at equal intervals from each other, but may be appropriately selected in consideration of the distribution of plasma density formed in the chamber by the antenna. In addition, the coolant may smoothly flow through the end 205 of the inner coil 201 and the end 206 of the outer coil 202.

Meanwhile, the central axes of the inner coil 201 and the outer coil 202 may be different from each other, and the inner coil and the outer coil may be located on different planes. Such an example is shown in FIG. 7. In FIG. 7, FIGS. 7A and 7B show that the central axes of the inner coil and the outer coil are different from each other, FIG. 7C shows that the inner coil is located on the top of the plane formed by the outer coil, and FIG. 7D shows the inner coil. It indicates that the outer coil is located in the lower part of the plane to be formed.

8 shows a schematic diagram of a rectangular plasma antenna which is another preferred example of an inductively coupled large area plasma antenna according to the present invention. The antenna 3 is composed of an inner coil 301 and an outer coil 302, and they are not closed, and the connection of the two coils 301 and 302 is connected to the inner coil 301 by the auxiliary auxiliary coil 303. ) Is guided to a position away from the plane formed by the plane and the outer coil 302 is connected to each other by the connection coil (304). The inner coil 301 and the outer coil 302 may have a square shape having the same width and length, or a rectangle having different lengths and widths. The end 305 of the inner coil 301 is connected to an input terminal (or output terminal), and the end 306 of the outer coil 302 is connected to an output terminal (or input terminal). Accordingly, the current i _in flowing in the inner coil 301 and the current i _ex flowing in the outer coil 302 flow in opposite directions, and apply an electromagnetic field to the inside of the reactor. Ends 305 and 306 of the inner and outer coils to which the input / output terminals are connected are located on one side outside the corners of the square antenna, and if possible, the input / output terminals are preferably formed at a close position. In addition, the terminal connected to the end 305 of the inner coil 301, preferably, to secure the height corresponding to the connection coil 304 and the upper end or the outer coil 302 of the end 306 of the outer coil 302 It passes over this closed area (307 shown by a dotted line) (308). In addition, the terminal connected to the end 306 of the outer coil 302, preferably, should be secured to the height corresponding to the connection coil 304 and connected outside the antenna area made by the outer coil 302 (309). The inner coil 301, the outer coil 302, the connection auxiliary coil 303 and the connection coil 304 is composed of a conductor. In addition, the inner coil 301 and the outer coil 302 may be located on different planes, and the coolant flows through the end 305 of the inner coil 301 and the end of the outer coil 302. The position of the inner coil 301 may deviate from the central axis of the outer coil 302.

Figure 9 shows another preferred example of a circular large area plasma antenna according to the present invention. The circular large area plasma antenna 4 is composed of an inner coil 401 and an outer coil 402, two coils 401 and 402 are closed, and the connection of the two coils 401 and 402 is connected. The auxiliary coil 403 is guided to a position away from the plane formed by the inner coil 401 and the outer coil 402 and is connected to each other by the connecting coil 404. The inner coil power terminal (or the end of the inner coil) 405 and the outer coil power terminal (or the end of the outer coil) 406 are located opposite to the connecting portions 403 and 404, preferably, the inner coil The power terminal 405 secures the height corresponding to the connection coil 404 and passes through the upper portion of the outer coil connecting terminal 406 or the upper portion of the outer coil 402 close to the outer coil connecting terminal 406 and the outer coil. The connection terminal 406 secures the height corresponding to the connection coil 404 and connects it. Therefore, when power is applied to the internal coil power terminal 405 (or the external coil power terminal 406), the internal coil 401 is applied. The current i _in flowing _in and the current i _ex flowing in the outer coil 402 flow in opposite directions. In addition, the coolant may flow through the inner coil power terminal 405 and the outer coil power terminal 406. In addition, the inner coil 401 and the outer coil 402 may be located on different planes. In addition, although the inductively coupled large-area plasma antenna 4 is shown in a circular shape, it may be changed in various forms. For example, the inner coil 401 may have an elliptical shape having a transverse radius greater than the longitudinal radius, or, conversely, an elliptical shape having an outer coil 402 having a shorter transverse radius than the vertical radius.

10 shows a schematic diagram of a rectangular inductively coupled large area plasma antenna. The rectangular inductively coupled large area plasma antenna 5 is composed of an inner coil 501 and an outer coil 502, two coils 501 and 502 are closed, and two coils 501 and 502. ) Is guided to a position away from the plane formed by the inner coil 501 and the outer coil 502 by the connecting auxiliary coil 503 is connected to each other by the connecting coil 504. The inner coil power terminal (or the end of the inner coil) 505 and the outer coil power terminal (or the end of the outer coil) 506 are located opposite to the connecting portions 503 and 504, preferably, the inner coil The power terminal 505 secures a height corresponding to the connection coil 504 and passes the upper portion of the outer coil connecting terminal 506 or the upper portion of the outer coil 502 close to the outer coil connecting terminal 506. The external coil connection terminal 506 secures the height corresponding to the connection terminal 504 and connects it. Therefore, when power is applied to the internal coil power terminal 505 (or the external coil power terminal 506), the internal coil ( The current i _in flowing in the 501 and the current i _ex flowing in the outer coil 502 flow in opposite directions. In addition, the coolant may flow through the internal coil power terminal 505 and the external coil power terminal 506. The inner coil 501 may have a rectangular shape having different horizontal and vertical lengths, and the outer coil 502 may have a rectangular shape. In addition, the inner coil 501 and the outer coil 502 may be located on different planes.

The inductively coupled large area plasma antenna may be used in various plasma generators including the plasma generator shown in FIG. 1. Specifically, a chamber in which a plasma is generated, a gas inlet for supplying a reaction gas into the chamber, a vacuum pump for maintaining a vacuum inside the chamber and discharging the reaction gas when the reaction is completed, and a substrate to be installed in the chamber. It can be used in a plasma generator including a substrate holder for placing the, a dielectric to isolate the antenna. When power is added from the impedance-matched rf power source to the antenna, rf power, ie, rf potential and current, is applied to the antenna in opposite directions to the inner coil and the outer coil, and an electromagnetic field having a uniform distribution inside the plasma generator. Will form. Therefore, a plasma having a uniform distribution is generated, and the generated plasma is incident by the other rf power source toward the substrate holder to which a negative DC bias voltage is applied, resulting in a uniform surface treatment of the uniform substrate. . If necessary, the antenna may be located inside the plasma generating space of the plasma generating device instead of the upper portion of the plasma generating device, or may be connected and used in parallel.

The inductively-coupled large area plasma antenna for the plasma generating apparatus of the present invention is composed of an inner and an outer coil so that the direction of current flows in opposite directions, thereby controlling the formation of an electromagnetic field generated in the inner coil and the outer coil at the center of the reactor. The generated plasma is uniformly formed in the space. In addition, the connection between the inner coil and the outer coil is made on a plane which is not the same as the plane formed by the inner coil and the plane formed by the outer coil, and the antenna coil is integrally formed to smoothly control the flow of the coolant. In addition, there is no need to additionally connect an unnecessary capacitor or inductor except for the resonance circuit, and the structure is very simple, which is easy to manufacture.

1 is a schematic diagram of a plasma generating apparatus generally used in the prior art.

2 is a schematic diagram of a planar spiral antenna which has been widely used in the above-described plasma generator.

3 is a schematic diagram of a transformer coupled balanced antenna according to Korean Patent Application No. 7010807/2000.

4 is a schematic diagram of a large area planar antenna in the form of a radiation structure according to Korean Patent Application No. 14578/1998.

5 is a schematic view of an antenna combined in a parallel type of Korean Patent Application No. 35702/1999.

6 to 10 are schematic diagrams of a preferred embodiment of the inductively coupled large area plasma antenna according to the present invention.

Claims (11)

An inner coil and an outer coil, wherein one end of the inner coil and the outer coil are connected to each other by a connecting portion at a position which is not the same as the plane formed by the inner coil and the plane formed by the outer coil, the inner coil and the There is only one connection portion connecting the external coil, the other end of the inner coil and the outer coil is connected to the power terminal, the connection portion and the power terminal of the inner coil and the outer coil has a structure located on the opposite surface, Inductively coupled large area plasma antenna used in plasma generators. The antenna of claim 1, wherein the antenna includes an inner coil, an outer coil, a connection auxiliary coil, and a connection coil, and one end of the inner coil and the outer coil is the same as the plane formed by the inner coil and the plane formed by the outer coil. It is connected to each other by the connection auxiliary coil and the connection coil in a plane not, the other end of the inner coil and the outer coil is connected to the power terminal, characterized in that the connecting portion and the power terminal has a structure located on the opposite side antenna. The antenna of claim 1, wherein a current flowing through the inner coil and a current flowing through the outer coil are opposite to each other. The antenna of claim 1, wherein the inner coil and the outer coil are not closed. The antenna of claim 1, wherein the inner coil and the outer coil are closed. The antenna of claim 1, wherein the inner coil and the outer coil are located on the same plane. The antenna of claim 1, wherein the central axes of the inner coil and the outer coil are the same. The antenna of claim 1, wherein the inner coil and the outer coil have a circular, rectangular or elliptical shape. A plasma generating apparatus comprising an inductively coupled large area plasma antenna according to any one of claims 1 to 8. The method of claim 9, wherein the plasma generating device is a chamber in which a plasma is generated, a gas inlet for supplying a reaction gas into the chamber, a vacuum pump for maintaining the inside of the chamber in a vacuum and discharge the reaction gas when the reaction is complete, the And a substrate holder for placing a substrate to be disposed in the chamber, and a dielectric for isolating the antenna. 10. The apparatus of claim 9, wherein the antenna is located outside of the plasma chamber.