KR100980287B1 - Inductively coupled plasma reactor having multi rf antenna - Google Patents

Abstract

The inductively coupled plasma reactor having multiple radio frequency antennas of the present invention includes a plasma reactor including a substrate support on which a substrate is to be placed and a dielectric window, and an induced electromotive force for generating an inductively coupled plasma into the plasma reactor through the dielectric window. And a magnetic core cover provided to cover the first radio frequency antenna, the first and second radio frequency antennas providing a magnetic flux entrance and exit toward the interior of the plasma reactor. The inductively coupled plasma reactor having multiple radio frequency antennas of the present invention includes multiple radio frequency antennas having a magnetic core cover to generate a more uniform and large area of high density plasma, and improves plasma ion energy control and plasma reproducibility. The yield can be improved.

Plasma, radio frequency antenna, inductive coupling, magnetic core

Description

INDUCTIVELY COUPLED PLASMA REACTOR HAVING MULTI RF ANTENNA}

The present invention relates to an inductively coupled plasma reactor using a radio frequency. Specifically, a multi-radio frequency antenna having a magnetic core cover can generate a more uniform large-area high-density plasma, and can control plasma ion energy. It relates to an inductively coupled plasma reactor that can improve yield by increasing plasma reproducibility.

Plasma is a highly ionized gas containing the same number of positive ions and electrons. 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 a variety of semiconductor manufacturing processes such as etching, deposition, cleaning, ashing, and the like.

There are a number of plasma sources for generating plasma, and the representative examples are capacitive coupled plasma and inductive coupled plasma using radio frequency.

Capacitively coupled plasma sources have the advantage of high process productivity compared to other plasma sources due to their high capacity for precise capacitive coupling and ion control. On the other hand, since the energy of the radio frequency power supply is almost exclusively connected to the plasma through capacitive coupling, the plasma ion density can only be increased or decreased by increasing or decreasing the capacitively coupled radio frequency power. However, increasing radio frequency power increases ion bombardment energy. As a result, in order to prevent damage caused by ion bombardment, there is a limit of radio frequency power supplied.

On the other hand, the inductively coupled plasma source can easily increase the ion density with the increase of the radio frequency power source, the ion bombardment is relatively low, it is known to be suitable for obtaining a high density plasma. Therefore, inductively coupled plasma sources are commonly used to obtain high density plasma. Inductively coupled plasma sources are typically developed using a radio frequency antenna (RF antenna) and a transformer (also called transformer coupled plasma). The development of technology to improve the characteristics of plasma, and to increase the reproducibility and control ability by adding an electromagnet or a permanent magnet or adding a capacitive coupling electrode.

Radio frequency antennas are generally used as spiral type antennas or cylinder type antennas. The radio frequency antenna is disposed outside the plasma reactor and transmits induced electromotive force into the plasma reactor through a dielectric window such as quartz. Inductively coupled plasma using a radio frequency antenna can obtain a high density plasma relatively easily, but the plasma uniformity is affected by the structural characteristics of the antenna. Therefore, efforts have been made to improve the structure of the radio frequency antenna to obtain a uniform high density plasma.

However, in order to obtain a large plasma, it is limited to widen the structure of the antenna or increase the power supplied to the antenna. For example, it is known that a non-uniform plasma is generated in the radiographic state by a standing wave effect. In addition, when high power is applied to the antenna, the capacitive coupling of the radio frequency antenna increases, so that the dielectric window must be thickened, thereby increasing the distance between the radio frequency antenna and the plasma, thereby lowering power transmission efficiency. Losing problems occur.

In the recent semiconductor manufacturing industry, plasma processing technology has been further improved due to various factors such as ultra-miniaturization of semiconductor devices, the enlargement of silicon wafer substrates for manufacturing semiconductor circuits, the enlargement of glass substrates for manufacturing liquid crystal displays, and the emergence of new target materials. This is required. In particular, there is a need for improved plasma sources and plasma processing techniques that have good processing capabilities for large area workpieces.

Therefore, an object of the present invention is to provide a more uniform large-area high-density plasma having a multi-radio frequency antenna having a magnetic core cover, and induction to improve the yield by increasing the plasma reproducibility and control of plasma ion energy It is to provide a combined plasma reactor.

One aspect of the present invention for achieving the above technical problem relates to an inductively coupled plasma reactor having multiple radio frequency antennas. An inductively coupled plasma reactor having multiple radio frequency antennas of the present invention comprises: a plasma reactor including a substrate support on which a substrate to be processed is placed and a dielectric window; First and second radio frequency antennas for providing induced electromotive force for inductively coupled plasma generation through the dielectric window into the plasma reactor; And a magnetic flux cover directed toward the interior of the plasma reactor and covering the first radio frequency antenna.

In one embodiment, the dielectric window has a cylindrical structure and constitutes an upper body of the plasma reactor, and the first and second radio frequency antennas have a cylindrical spiral structure installed as sidewalls of the dielectric window.

In one embodiment, the second radio frequency antenna has an overlapping structure covering along the first radio frequency antenna.

In an embodiment, the magnetic core cover has a structure installed between the first and second radio frequency antennas, a structure covering all of the overlapping first and second radio frequency antennas, or the first and second radios. The mounting structure includes any one of an installation structure including one magnetic core installed between the frequency antennas and another magnetic core cover covering the second radio frequency antenna.

In one embodiment, a third radio frequency antenna is installed outside the ceiling of the dielectric window.

In one embodiment, another magnetic core cover covering the third radio frequency antenna.

In one embodiment, it includes third and fourth radio frequency antennas mounted to the outer ceiling of the dielectric window.

In one embodiment, another magnetic core cover covering the third radio frequency antenna.

In one embodiment, the dielectric window has a cylindrical structure and constitutes an upper body of the plasma reactor, the first radio frequency antenna is installed to the sidewall of the dielectric window, the second radio frequency antenna is the dielectric window Is installed on the ceiling.

In one embodiment, a third radio frequency antenna is installed on the ceiling of the dielectric window.

In one embodiment, another magnetic core cover covering the third radio frequency antenna.

In one embodiment, the substrate support is biased by receiving one or more radio frequencies.

According to the inductively coupled plasma reactor having a multi-radio frequency antenna of the present invention, a multi-radio frequency antenna having a magnetic core cover can be used to generate a more uniform high-density plasma, and can control plasma ion energy and plasma reproducibility. Increasing the yield can be improved.

In order to fully understand the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Embodiment of the present invention may be modified in various forms, the scope of the invention should not be construed as limited to the embodiments described in detail below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Therefore, the shape of the elements in the drawings and the like may be exaggerated to emphasize a more clear description. It should be noted that the same members in each drawing are sometimes shown with the same reference numerals. Detailed descriptions of well-known functions and constructions which may be unnecessarily obscured by the gist of the present invention are omitted.

1 shows an inductively coupled plasma reactor according to a preferred embodiment of the present invention.

Referring to FIG. 1, the inductively coupled plasma reactor 10 of the present invention is a plasma reactor 10 through a substrate support 20, a dielectric window 12, and a dielectric window 12 on which a substrate 22 to be processed is placed. First and second radio frequency antennas 30, 32, and magnetic flux entrances and exits that provide induction electromotive force for inductively coupled plasma generation into the interior of the plasma reactor 10 with the first radio frequency antenna 30 It includes a magnetic core cover 31 installed to cover. The dielectric window 12 has a cylindrical structure and constitutes an upper body of the plasma reactor 10. The lower body 11 includes a substrate support 20. The first and second radio frequency antennas 30 and 32 have a cylindrical spiral structure which is installed as a side wall of the dielectric window 12. As shown in the figure, the first and second radio frequency antennas 30, 32 have a cylindrical spiral structure which is alternately arranged. The first radio frequency antenna 30 is connected to the main power supply 40 via an impedance matcher 41. The second radio frequency antenna 32 is connected to another main power supply 42 via another impedance matcher 41. The two main power sources 40, 42 may each supply the same or different radio frequency power.

 FIG. 2 is a partial perspective view illustrating a radio frequency antenna covered by a magnetic core cover, and FIG. 3 is a view for explaining an induction magnetic field focused by the magnetic core cover.

As shown in FIGS. 2 and 3, the first radio frequency antenna 30 is covered by a magnetic core cover 31. The magnetic core cover 30 covers the first radio frequency antenna 30 with the magnetic flux entrance and exit facing the interior of the plasma reactor. Thus, as shown in FIG. 3, the magnetic flux generated by the first radio frequency antenna 30 is strongly concentrated by the magnetic core cover 31 to form an induced magnetic field inside the plasma reactor 10. On the other hand, unlike the first radio frequency antenna 30, the second radio frequency antenna 32 is installed outside the dielectric window 12 as it is. Therefore, more concentrated plasma discharge is generated inside the plasma reactor 10 because the induced electromotive force is formed by the first radio frequency antenna 32 in the outer periphery of the plasma reactor 10.

The magnetic core cover 31 has a vertical cross-sectional structure having a horseshoe shape and is installed such that the magnetic flux entrance and exit points toward the dielectric window 12. The magnetic core cover 31 is made of ferrite but may be made of other alternative materials. Magnetic core cover 31 may be configured by assembling a plurality of horseshoe-shaped ferrite core pieces. In the case of using a plurality of pieces, each piece can be connected by inserting a nonmagnetic material layer such as an insulating material on the assembly surface. When the nonmagnetic material layer is formed, the induced electromotive force by the first radio frequency antenna 30 may be more uniformly transmitted into the plasma reactor 10, thereby increasing the plasma uniformity. Although not shown, a Faraday shield may be selectively configured between the dielectric window 12 and the first and second radio frequency antennas 30 and 32.

On the other hand, when the first and second radio frequency antennas 30 and 32 are driven by different frequencies, it is possible to further improve the process productivity by further improving the density of uniform plasma generation and the ability to control plasma ion energy. In addition, since the first and second radio frequency antennas 131 and 133 are supplied with different frequencies, capacitive coupling occurs due to a relative voltage difference. Thus, capacitive coupling occurs between the first and second radio frequency antennas 30 and 32, which further complicates the plasma ion acceleration path, resulting in a more uniform high density plasma.

4 is a cross-sectional view showing the superimposed radio frequency antenna and the magnetic core cover.

Referring to FIG. 4, the first and second radio frequency antennas 30 and 32 may have a structure in which the second radio frequency antenna 32 is superimposed on the first radio frequency antenna 30. In this case, the magnetic core cover 31 may be installed between the first radio frequency antenna 30 and the second radio frequency antenna 32 to cover the first radio frequency antenna 30. Alternatively, although not shown in the drawings, the magnetic core cover may be installed outside the second radio frequency antenna 32 so as to cover both the overlapping first and second radio frequency antennas 30 and 32. Alternatively, the structure may include one magnetic core cover between the first and second radio frequency antennas and another magnetic core cover covering the second radio frequency antenna.

Again, referring to FIG. 1, substrate support 20 may be biased by one or more bias power supplies 45, 46 that supply a radio frequency for bias. One or more bias power supplies 45, 46 are connected to the substrate support through impedance matcher 165. The dual bias structure of the substrate support 20 may further improve the plasma ion energy control ability on the surface of the substrate 22 to further improve the process productivity. The substrate support 20 may have a single bias structure. Alternatively, the support 20 may be modified to have a structure having a zero potential without supplying bias power. And the support 20 may include an electrostatic chuck. And the support 20 may include a heater.

The plasma reactor 10 may be provided with a cooling water supply channel for temperature control. The cooling water supply channel may use the first and second radio frequency antennas 30 and 32 or may constitute separate cooling channels.

5 to 7 are views showing various modifications of the inductively coupled plasma reactor provided with a radio frequency antenna on the ceiling of the reactor.

First, referring to FIG. 5, the plasma reactor 10 of the modification may be provided with another radio frequency antenna 37 outside the ceiling 13 of the dielectric window 12. The other radio frequency antenna 37 is connected to another main power source 47 through another impedance matcher 48. The ceiling 13 of the dielectric window 12 may have a domed or flat structure. As shown in FIG. 6, when the radio frequency antenna 37 is provided outside the ceiling 13, only the first radio frequency antenna 30 may be provided on the side of the dielectric window 12.

As shown in FIG. 7 or FIG. 8, two radio frequency antennas 37-1 and 37-2 may be provided outside the ceiling 13, and two radio frequency antennas 37-1 and 37-2 may be provided. ) May be driven by receiving different or the same radio frequency power by independent main power sources 47-1 and 47-2 and impedance matchers 48-1 and 48-2, respectively. Here, the two radio frequency antennas 37-1 and 37-2 may have alternating arrangements or may be positioned at the center and the outside, respectively. In addition, even in the case of two radio frequency antennas 37-1 and 37-2 installed on the ceiling 13, any one may include a magnetic core cover 38. As shown in FIG. 7, the structure may be disposed entirely in the electric bath 13, or as shown in FIG. 8.

The multiple radio frequency antennas provided in the plasma reactor 10 of the present invention as described above illustrate a structure in which power is supplied by independent main power sources. However, more than one radio frequency antenna can be driven by one main power source. In this case, the number of main power sources can be reduced. Although not shown in the drawings in detail, it is obvious that the supply and exhaust structure of the process gas should be provided. The gas supply may, for example, have one or more gas supply nozzles or may have a gas shower head. Alternatively, the gas supply structure may be branched in various ways from the inside of the plasma reactor 10 and multiple gas injection may be performed.

The inductively coupled plasma reactor of the present invention includes a magnetic core cover for at least one radio frequency antenna for multiple radio frequency antennas installed on the side wall, the ceiling, or both of the plasma reactors, so that a large area of plasma can be seen inside the plasma reactor. Allow it to occur evenly. To this end, the arrangement of the antenna may take a variety of ways. For example, different antennas may have alternating arrangements, sequential arrangements, or overlapping structures. Alternatively, the winding density may be adjusted differently as appropriate.

Embodiments of the inductively coupled plasma reactor having multiple radio frequency antennas of the present invention described above are merely exemplary, and those skilled in the art to which the present invention pertains have various modifications and other equivalent implementations therefrom. You can see that examples are possible. Accordingly, it is to be understood that the present invention is not limited to the above-described embodiments. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims. It is also to be understood that the present invention includes all modifications, equivalents, and substitutes within the spirit and scope of the invention as defined by the appended claims.

 The inductively coupled plasma reactor having multiple radio frequency antennas of the present invention can be very usefully used in plasma processing processes for forming various thin films such as semiconductor integrated circuits, flat panel displays, and solar cells.

1 shows an inductively coupled plasma reactor according to a preferred embodiment of the present invention.

2 is a partial perspective view showing a radio frequency antenna covered by a magnetic core cover.

3 is a view for explaining an induction magnetic field focused by the magnetic core cover.

4 is a cross-sectional view showing the superimposed radio frequency antenna and the magnetic core cover.

5 to 7 show various modified examples of an inductively coupled plasma reactor in which a radio frequency antenna is installed on the ceiling of the reactor.

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

10: plasma reactor

11: lower body

12: dielectric window

13: ceiling

20: substrate support

22: substrate to be processed

30, 32, 33: radio frequency antenna

31, 34, 38: magnetic core cover

35, 36: induction magnetic field

40, 42, 47, 47-1, 47-2: main power source

41, 43, 44, 48, 48-1, 48-2: impedance matcher

45, 46: bias power supply

Claims (12)

A plasma reactor comprising a substrate support on which a substrate to be processed is placed and a dielectric window; First and second radio frequency antennas for providing induced electromotive force for inductively coupled plasma generation through the dielectric window into the plasma reactor; A third radio frequency antenna installed outside the ceiling of the dielectric window; An inductively coupled plasma reactor having multiple radio frequency antennas comprising a magnetic core cover installed such that a magnetic flux entrance and exit toward the interior of said plasma reactor and covering said first radio frequency antenna. The method of claim 1, The dielectric window has a cylindrical structure and constitutes an upper body of the plasma reactor, And the first and second radio frequency antennas have multiple radio frequency antennas having a cylindrical spiral structure installed on sidewalls of the dielectric window. The method of claim 1, And the second radio frequency antenna has multiple radio frequency antennas having an overlapping structure covering the first radio frequency antenna. The method of claim 3, The magnetic core cover is installed between the first and second radio frequency antennas, covers the overlapping first and second radio frequency antennas, or is installed between the first and second radio frequency antennas. An inductively coupled plasma reactor having a multiple radio frequency antenna having any one of the mounting structures including one magnetic core and another magnetic core cover covering the second radio frequency antenna. delete delete The method of claim 2, An inductively coupled plasma reactor having multiple radio frequency antennas comprising a fourth radio frequency antenna mounted to an outer ceiling of the dielectric window. The method of claim 1, An inductively coupled plasma reactor having multiple radio frequency antennas comprising another magnetic core cover covering the third radio frequency antenna. The method of claim 1, The dielectric window has a cylindrical structure and constitutes an upper body of the plasma reactor, The first radio frequency antenna is installed to the side wall of the dielectric window, the second radio frequency antenna inductively coupled plasma reactor having a multiple radio frequency antenna is installed to the ceiling of the dielectric window. delete delete The inductively coupled plasma reactor of claim 1, wherein the substrate support has multiple radio frequency antennas biased by receiving one or more radio frequencies.

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