KR20100047723A - Inductively coupled plasma reactor - Google Patents

Abstract

PURPOSE: By using for a control antenna controlling direction and size of the induced electromotive force created in the main antenna the inductively coupled plasma source occurs the uniform high density plasma. CONSTITUTION: A reaction chamber(12) has the plasma discharge area. A main antenna(21) offers the first induced electromotive force for occurring the plasma discharge to the plasma discharge area. A dielectric window(20) is installed in the between discharge domain of the reaction chamber and main antenna. For the control antenna(22) offers the second induced electromotive force for the variable of the first induced electromotive force.

Description

Inductively Coupled Plasma Reactor {INDUCTIVELY COUPLED PLASMA REACTOR}

The present invention relates to an inductively copled plasma reactor using a radio frequency. Specifically, a control antenna capable of controlling the direction and magnitude of induced electromotive force generated from a radio frequency main antenna is used. The present invention relates to an inductively coupled plasma reactor capable of generating a more uniform high density plasma and improved control of plasma ion energy by variably controlling the induced electromotive force of the main antenna.

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 the radio frequency force increases the 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.

By the way, inductively coupled plasma using a radio frequency antenna is relatively easy to obtain a high density plasma, there is a problem that the plasma uniformity is affected by the structural characteristics of the antenna. Specifically, it is difficult to obtain a uniform plasma because the magnetic flux density of the center portion of the wireless antenna is higher than that of other regions. In addition, there is a problem that it is difficult to control the induced electromotive force while maintaining a uniform electromagnetic field. Therefore, there is a need for a plasma processing technique that obtains a uniform high density plasma and has improved control capability.

Accordingly, an object of the present invention is to solve the above-mentioned problems, and an object thereof is to control plasma induced energy of the main antenna by using a control antenna capable of controlling the direction and magnitude of induced electromotive force generated from the main antenna. The present invention provides an inductively coupled plasma reactor capable of generating more uniform and high density plasma.

One aspect of the present invention for achieving the above technical problem relates to an inductively coupled plasma reactor. An inductively coupled plasma reactor of the present invention comprises: a reaction chamber having a plasma discharge region, a main antenna providing a first induced electromotive force for generating a plasma discharge to the plasma discharge region, between the main antenna and a discharge region of the reaction chamber; It includes a dielectric window installed, a control antenna for providing a second induced electromotive force for the variable of the first induced electromotive force, a control circuit for controlling the direction and magnitude of the second induced electromotive force.

In one embodiment, the control circuit may include a switching unit for switching the direction of the second induced electromotive force in the same direction or the opposite direction to the direction of the first induced electromotive force.

In one embodiment, the control circuit may include a turn variable circuit for varying the number of turns of the control antenna.

In one embodiment, the inductively coupled plasma reactor may further include a magnetic core provided between the main antenna and the control antenna.

In one embodiment, the control antenna may include a plurality of antennas.

In one embodiment, the dielectric window may be a flat structure or a domed structure.

In an embodiment, the dielectric window includes a plurality of gas supply holes opened into the reaction chamber, and includes a gas supply unit supplying a process gas to a discharge region of the reaction chamber through the plurality of gas supply holes. can do.

In one embodiment, the gas supply may include one gas supply channel or two or more separate gas supply channels.

In one embodiment, the reaction chamber may include a substrate support for supporting a substrate to be processed, and may include one or more bias power sources for supplying bias power to the substrate support.

In one embodiment, it may include a power supply for providing radio frequency power to the control antenna unit.

In one embodiment, it may include an impedance matcher provided between the control antenna unit and the power supply source to match the impedance of both ends.

According to the inductively coupled plasma reactor of the present invention, by controlling the induced electromotive force of the main antenna variably by using a control antenna capable of controlling the direction and magnitude of the induced electromotive force generated from the main antenna, an improved control ability of plasma ion energy is obtained. And a more uniform high density plasma.

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 is a block diagram of 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 includes a reaction chamber 12 having a plasma discharge region and a main antenna 21 providing a first induced electromotive force for generating plasma discharge into the plasma discharge region. It is provided. A dielectric window 20 is formed between the main antenna 21 and the discharge region of the reaction chamber 12. And a control antenna 22 for providing a second induced electromotive force for varying the first induced electromotive force, and a control circuit 50 for controlling the direction and magnitude of the second induced electromotive force.

For example, a plate-shaped dielectric window 20 constitutes a ceiling of the reaction chamber 12, and a plate helical main antenna 21 is installed thereon. The main antenna 21 is electrically connected to a main antenna power supply 40 which provides radio frequency power through the main antenna impedance matcher 41. The control antenna 22 may be provided at an upper end of the main antenna 21, and a magnetic core 24 may be installed between the main antenna 21 and the control antenna 22. The control circuit 50 controls the direction and magnitude of the second induced electromotive force generated by the control antenna 22. The control antenna 22 is electrically connected to a control antenna power supply 48 that provides radio frequency power through the control antenna impedance matcher 48.

The inductively coupled plasma reactor 10 of the present invention variably controls the induced electromotive force of the main antenna 21 by using the control antenna 22 capable of controlling the direction and magnitude of the induced electromotive force generated by the main antenna 21. This allows greater control over plasma ion energy and more uniform high density plasma generation. The main antenna power supply 40 uses the main antenna impedance matcher 41, but may be configured using a radio frequency generator capable of controlling the output without a separate impedance matcher.

The reaction chamber 12 may be made of a metal material such as aluminum, stainless steel, or copper. Or it may be made of coated metal, for example anodized aluminum or nickel plated aluminum. Alternatively, a composite metal in which carbon nanotubes are covalently bonded may be used. Alternatively, it may be made of refractory metal. Alternatively, it is also possible to fabricate the reactor body 12 in whole or in part with an electrically insulating material such as quartz, ceramic. As such, the reaction chamber 12 may be made of any material suitable for performing the intended plasma process.

2A and 2B are diagrams showing a state of switching to control the direction of induced electromotive force.

Referring to FIG. 2A, the main antenna 21 provides a first induced electromotive force H1, and the control antenna 22 provides a second induced electromotive force H2. The total induced electromotive force H total formed in the magnetic core 24 is the sum of the first induced electromotive force H1 and the second induced electromotive force H2.

Referring to FIG. 2B, the control antenna 22 is switched in the opposite direction in FIG. 2A to provide the second induced electromotive force H2 in the opposite direction. In this case, the total induced electromotive force H total formed in the magnetic core 24 becomes the difference between the first induced electromotive force H1 and the second induced electromotive force H2.

As a result, the total induced electromotive force H total provided to the plasma discharge region increases or decreases according to the direction of the second induced electromotive force H2 provided by the control antenna 22.

3 is a view illustrating an operating state of a control circuit including a switching unit and a variable number of turn circuit.

Referring to FIG. 3, the control circuit 50 includes a switching unit 51 and a turn variable circuit 53. The switching unit 51 switches the direction of the second induced electromotive force in the same direction or the opposite direction to the direction of the first induced electromotive force. The turn variable circuit 53 varies the number of turns of the control antenna 22. That is, the control circuit 50 controls the direction and magnitude of the second induced electromotive force.

4 is a view showing the configuration and operation of a control circuit for controlling a plurality of control antennas according to another embodiment of the present invention.

Since the plasma discharge region is not locally uniform in magnetic flux density, a plurality of control antennas 22a and 22b can be used to vary the intensity depending on the region, thereby making it possible to create an electromagnetic field with a uniform magnetic flux density as a whole.

5 and 6 show various modifications of the domed inductively coupled plasma reactor.

As shown in FIGS. 5 and 6, the dielectric window 20 may have a domed structure. A gas distribution plate 34 may be provided as shown in FIG. 5 to supply gas into the reaction chamber 12, or a gas outlet 32 may be provided as shown in FIG. 6.

FIG. 7 is a cross-sectional view illustrating the gas outlet 32 of FIG. 6 in more detail. Gas is supplied into the reaction chamber 12 through the plurality of holes 35 provided in the gas blowing holes 32.

 The shape of the dielectric window 20 and the gas outlet 32 can be modified into any other type of structure for uniform generation of the plasma.

The structure of the reaction chamber 12 and the substrate support 14 may have a structure suitable for the uniform generation of the plasma, for example, a circular structure, a square structure, or any other structure depending on the substrate 16 to be processed. have. The substrate 16 to be processed is, for example, substrates such as wafer substrates, glass substrates, plastic substrates, etc., for the manufacture of various devices such as semiconductor devices, display devices, solar cells, and the like. It is connected to a gas outlet 11 and a vacuum pump (not shown) provided in the reaction chamber 12.

The substrate support 14 is connected and biased to one or more bias power sources 42 and 44. For example, two bias power sources 42, 44 that supply different radio frequency power sources are electrically connected to the substrate support 14 through a common impedance matcher 46 (or each impedance matcher). Biased. The dual bias structure of the substrate support 14 facilitates plasma generation inside the reaction chamber 12, and further improves plasma ion energy control to improve process productivity. Alternatively, it may be modified to a single bias structure. Alternatively, the substrate support 14 may be modified to have a zero potential without supplying bias power. Substrate support 14 may include an electrostatic chuck, and in addition or separately may include a heater.

8 is a view showing a modification of the plate-type inductively coupled plasma reactor.

Referring to FIG. 8, the upper portion of the dielectric window 20 includes a gas inlet 30 and a gas distribution plate 34 connected to a gas supply source (not shown). The process gas is input into the reaction chamber 12 through 34. The lower end of the gas distribution plate 34 is provided with a control antenna 22, a magnetic core 24, and a main antenna 32, and a plurality of openings 66 are formed in the dielectric window 20. By such a structure, the process gas is evenly distributed and supplied into the reaction chamber 12.

Embodiments of the inductively coupled plasma reactor of the present invention described above are merely illustrative, and those skilled in the art to which the present invention pertains may various modifications and equivalent other embodiments. You will know. Therefore, it will be understood that the present invention is not limited only to the form mentioned in the above detailed description. 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.

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

2A and 2B are diagrams showing a state of switching to control the direction of induced electromotive force.

3 is a view illustrating an operating state of a control circuit including a switching unit and a variable number of turn circuit.

4 is a view showing the configuration and operation of a control circuit for controlling a plurality of control antennas according to another embodiment of the present invention.

5 and 6 show various modifications of the domed inductively coupled plasma reactor.

FIG. 7 is a cross-sectional view illustrating the gas outlet of FIG. 6 in more detail.

8 is a view showing a modification of the plate-type inductively coupled plasma reactor.

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

10: inductively coupled plasma reactor 11: gas outlet

12: reaction chamber 14: substrate support

16: substrate to be processed 20: dielectric window

21: main antenna 22: control antenna

22a: first control antenna 22b: second control antenna

24: magnetic core 24a: first magnetic core

24b: second magnetic core 30: gas inlet

32: gas outlet 34: gas distribution plate

35: hole 36: opening

40: main antenna power source 41: main antenna impedance matcher

42, 44: bias power source 46: impedance matcher

47: control antenna power source 48: control antenna impedance matcher

50: control circuit 51: first control antenna switching unit

52: second control antenna switching unit

53: first antenna turn variable circuit

54: second control antenna turn variable circuit

60: Splitter 70: RPG

80: control unit

Claims (11)

A reaction chamber having a plasma discharge region; A main antenna for providing a first induced electromotive force for generating a plasma discharge to the plasma discharge region; A dielectric window disposed between the main antenna and a discharge region of the reaction chamber; A control antenna for providing a second induced electromotive force for varying the first induced electromotive force; Inductively coupled plasma reactor comprising a control circuit for controlling the direction and magnitude of the second induced electromotive force. According to claim 1, The control circuit And a switching unit for switching the direction of the second induced electromotive force in the same direction or the opposite direction to the direction of the first induced electromotive force. The method according to claim 1 or 2, The control circuit Inductively coupled plasma reactor comprising a variable number of turns circuit for varying the number of turns of the control antenna. The method of claim 1, Inductively coupled plasma reactor further comprises a magnetic core provided between the main antenna and the control antenna. The method of claim 1, The control antenna is an inductively coupled plasma reactor, characterized in that it comprises a plurality of antennas. The method of claim 1, The dielectric window is an inductively coupled plasma reactor, characterized in that the planar structure or domed structure. According to claim 1, The dielectric window is A plurality of gas supply holes opened into the reaction chamber, And a gas supply unit supplying a process gas to a discharge region of the reaction chamber through the plurality of gas supply holes. The method of claim 7, wherein The gas supply unit An inductively coupled plasma reactor comprising one gas supply channel or two or more separate gas supply channels. According to claim 1, The reaction chamber A substrate support for supporting a substrate to be processed, And one or more bias power sources for supplying bias power to the substrate support. According to claim 1, Inductively coupled plasma reactor characterized in that it comprises a power supply for providing radio frequency power to the control antenna unit. The method of claim 10, And an impedance matcher provided between the control antenna unit and the power supply source to match impedances at both ends.

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