KR102467966B1 - Hybrid plasma generator and control method of hybrid plasma generator - Google Patents

Abstract

An apparatus for generating a hybrid plasma according to an embodiment includes an upper chamber, a capacitive coupled plasma module disposed above the upper chamber, an inductively coupled plasma module disposed on a side surface of the capacitive coupled plasma module, and the inductively coupled plasma module. A current control module connected to the upper part of the antenna of the inductively coupled plasma module to control the current flowing to the inductively coupled plasma module and connected to the lower part of the antenna of the inductively coupled plasma module to control the magnitude of the voltage applied to the inductively coupled plasma module. It may include a voltage regulation module that does.

Description

Hybrid plasma generator and control method of hybrid plasma generator

The present invention relates to a hybrid plasma generating device and a control method of the hybrid plasma generating device, and more specifically, in a hybrid plasma generating device including a capacitive coupled plasma generating module and a flow coupled plasma generating module, an inductively coupled plasma generating module. The present invention relates to a technique for controlling the magnitude of current and voltage applied to an inductively coupled plasma generating module using variable capacitors connected to input terminals and output terminals of the plasma generating module, respectively.

Plasma is an ionized gas, composed of positive ions, negative ions, electrons, excited atoms, molecules, and chemically very active radicals. Also called the fourth state. This plasma contains ionized gas and is very useful in semiconductor manufacturing processes such as accelerating it using an electric or magnetic field or causing a chemical reaction to clean, etch, or deposit a wafer or substrate.

Recently, plasma generators that generate high-density plasma are used in semiconductor manufacturing processes, and there are several plasma modules for generating plasma. Capacitive coupled plasma (CCP) using radio frequency and inductively coupled plasma (ICP) are representative examples.

The capacitive coupled plasma module has an advantage of higher process productivity than other plasma modules due to accurate capacitive coupling control and high ion control capability. On the other hand, since the energy of the radio frequency power source is coupled to the plasma almost exclusively through capacitive coupling, the plasma ion density can be increased or decreased only by increasing or decreasing the capacitively coupled radio frequency power. However, increasing radio frequency power increases the ion bombardment energy. As a result, in order to prevent damage due to ion bombardment, radio frequency power has limitations.

Meanwhile, the inductively coupled plasma module is known to be suitable for obtaining high-density plasma because it can easily increase ion density with an increase in radio frequency power and has relatively low ion impact. Therefore, inductively coupled plasma modules are generally used to obtain high-density plasma. Inductively coupled plasma modules are being developed in a typical way using a radio frequency antenna (RF antenna) and a method using a transformer (also referred to as transformer coupled plasma).

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

However, widening the antenna structure or increasing the power supplied to the antenna in order to obtain large-area plasma has limitations. For example, it is known that a radially non-uniform plasma is generated by a standing wave effect. In addition, when high power is applied to the antenna, capacitive coupling of the radio frequency antenna increases, so that the dielectric window must be thick, and as a result, the distance between the radio frequency antenna and the plasma increases, resulting in low power transfer efficiency. A losing problem arises.

Recently, in the semiconductor manufacturing industry, a more advanced plasma processing technology is required due to various factors such as ultra-miniaturization of semiconductor devices and enlargement of silicon wafer substrates for manufacturing semiconductor circuits. A hybrid plasma generating device combining type plasma sources is being developed.

However, in the case of the hybrid plasma generator according to the prior art, plasma is generated by independently controlling the capacitive coupled plasma module and the inductively coupled plasma module, but when the capacitive coupled plasma module and the inductively coupled plasma module are combined As the plasma is generated without considering the balance conditions and problems of the generated source, there is a problem in that the efficiency of the hybrid plasma generator is low.

Republic of Korea Patent Publication No. 10-2009-00974627A (2009.09.08) - Mixed plasma generating device and method, and electrothermal cooking device using mixed plasma

Therefore, a hybrid plasma generating device and a control method of the hybrid plasma generating device according to an embodiment are inventions designed to compensate for the above-described problems, and include variable capacitors connected to an input terminal and an output terminal of an inductively coupled plasma generating module, respectively. It is to provide a hybrid plasma generating device and a control method of the hybrid plasma generating device capable of controlling the magnitude of the current and voltage applied to the inductively coupled plasma generating module using the inductively coupled plasma generating module.

An apparatus for generating a hybrid plasma according to an embodiment includes an upper chamber, a capacitive coupled plasma module disposed above the upper chamber, an inductively coupled plasma module disposed on a side surface of the capacitive coupled plasma module, and the inductively coupled plasma module. A current control module connected to the upper part of the antenna of the inductively coupled plasma module to control the current flowing to the inductively coupled plasma module and connected to the lower part of the antenna of the inductively coupled plasma module to control the magnitude of the voltage applied to the inductively coupled plasma module. It may include a voltage regulation module that does.

One side of the current control module may be connected to an upper portion of the antenna, and the other side of the current control module may be connected to a power module supplying power to the inductively coupled plasma module.

One side of the voltage control module may be connected to a lower part of the antenna, and the other side of the voltage control module may be connected to a grounding part of the hybrid plasma generating device.

The current control module may include a first variable capacitor, and the voltage control module may include a second variable capacitor.

The control module may further include a control module that controls capacitances of the first variable capacitor and the second variable capacitor.

The control module may control the size of a current flowing through the antenna of the inductively coupled plasma module and the electrode of the capacitively coupled plasma module by controlling the size of the capacitance of the first variable capacitor.

The control module may control the size of the voltage applied to the antenna of the inductively coupled plasma module by controlling the size of the capacitance of the second variable capacitor.

The control module may control the capacitance of the second variable capacitor so that phases of voltages of the input and output terminals of the antenna are opposite to each other and voltages are equal to each other.

A control method of a hybrid plasma generator including a capacitively coupled plasma module and an inductively coupled plasma module according to another embodiment includes the control of the hybrid plasma using a first variable capacitor connected to an upper portion of an antenna of the inductively coupled plasma module. Controlling the current flowing through the inductively coupled plasma module and controlling the magnitude of the voltage applied to the inductively coupled plasma module using a second variable capacitor connected to a lower part of the antenna of the inductively coupled plasma module. can include

The controlling of the magnitude of the voltage may include controlling the magnitude of the capacitance of the second variable capacitor so that the phases of the voltages at the input terminal and the output terminal of the antenna are opposite to each other and the magnitudes of the voltages are equal to each other. have.

The hybrid plasma generating device and the hybrid plasma generating device according to an embodiment can generate a desired type of plasma source by adjusting the amount of current flowing through the capacitively coupled plasma module and the inductively coupled plasma module using a variable capacitor. . In addition, since the magnitude of the voltage applied to the antenna can be reduced by using a variable capacitor, capacitive coupling and sputtering problems generated in the hybrid plasma generator can be reduced, so that a higher density plasma can be formed. There are advantages to

In addition, since the capacitance value of the variable capacitor can be controlled in real time by the control module, the amount and density of generated plasma can be controlled in real time according to the user's desire.

1 is a block diagram showing some components of a hybrid plasma generator according to an embodiment of the present invention.
2 is a plan view of a hybrid plasma generator according to an embodiment of the present invention when viewed from above.
3 is a cross-sectional view of a hybrid plasma generating device according to an embodiment of the present invention.
4 is a diagram illustrating a state in which a power module supplies power to a hybrid plasma generating device according to an embodiment of the present invention.
5 is a diagram illustrating a state in which variable capacitors are disposed in a current control module and a voltage control module according to an embodiment of the present invention.
6 is a diagram showing experimental results of plasma generation density according to a change in a variable capacitor value in order to prove the effect according to the present invention.

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing an embodiment of the present invention, if it is determined that a detailed description of a related known configuration or function hinders understanding of the embodiment of the present invention, the detailed description thereof will be omitted. In addition, embodiments of the present invention will be described below, but the technical idea of the present invention is not limited or limited thereto and can be modified and implemented in various ways by those skilled in the art.

In addition, terms used in this specification are used to describe embodiments, and are not intended to limit and/or limit the disclosed invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, terms such as "include", "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or the existence or addition of more other features, numbers, steps, operations, components, parts, or combinations thereof is not excluded in advance.

In addition, throughout the specification, when a part is said to be “connected” to another part, this is not only the case where it is “directly connected”, but also the case where it is “indirectly connected” with another element in the middle. Terms including ordinal numbers, such as "first" and "second" used herein, may be used to describe various components, but the components are not limited by the terms.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted.

1 is a block diagram showing some components of a hybrid plasma generator according to an embodiment of the present invention, and FIG. 2 is a plan view of the hybrid plasma generator according to an embodiment of the present invention when viewed from above, 3 is a cross-sectional view of a hybrid plasma generating device according to an embodiment of the present invention.

1 to 3, the hybrid plasma generator 1 according to the present invention includes a capacitive coupled plasma module 100, an inductively coupled plasma module 200, a current control module 10, a voltage control module ( 20), a power module 30, a control module 40, an upper chamber 50 and a lower chamber 60.

Referring to FIGS. 2 and 3 , the capacitively coupled plasma module 100 has a structure penetrating from the upper center to the lower center of the reaction chamber 50 of the hybrid plasma generating device 1, and inductively coupled plasma The module 200 may be configured to surround the capacitive coupled plasma module 100 outside the outer circumferential surface of the capacitive coupled plasma module 100 .

The form in which the inductively coupled plasma module 200 surrounds the capacitively coupled plasma module 100 may have a circular donut shape as shown in FIG. 3 , and thus the capacitively coupled plasma module 100 may have a circular shape. However, the form that the inductively coupled plasma module 200 may have is not limited thereto as long as the inductively coupled plasma module 200 can be expressed as a form surrounding the capacitively coupled plasma module 100. Depending on the type and characteristics of the substrate to be used, polygonal donut shapes and polygonal shapes are also possible.

Power applied to the hybrid plasma generator 1 may be supplied from the power module 30, low frequency (LF) is applied to the capacitive coupled plasma module 100, and the inductively coupled plasma module 200 ) can be applied with high frequency (HF), and the applied frequency can be changed according to the process conditions.

For example, when a low frequency is applied to the capacitive coupled plasma module 100 and a high frequency is applied to the inductively coupled plasma module 200, the frequency applied to the capacitive coupled plasma module 100 is 400 kHz to 12.56 MHz. , and the range of frequencies applied to the inductively coupled plasma module 200 surrounding the capacitively coupled plasma module 100 may be in the range of 13 MHz to 60 MHz.

Referring to FIG. 3, the configuration of the hybrid plasma generating device 1 will be described in detail, the hybrid plasma generating device 1 according to the present invention includes an upper chamber 50 and a lower chamber 60, and an upper chamber ( 80) and penetrates toward the lower chamber 50 and includes a first electrode 120 disposed in the upper chamber 50 and a second electrode 140 opposing the first electrode 120. An antenna 220 formed in the module 100 and the upper chamber 50 and including at least one unit coil on a quartz plate 240 disposed at a predetermined distance from the first electrode 120 It may be configured to include an inductively coupled plasma module 200 that does.

At this time, the first electrode 120 is connected to the upper electrode rod 120a protruding out of the upper chamber 50 and the upper electrode rod 120a, and is installed in a space where the capacitively coupled plasma module 100 is disposed. It may be formed in an I-shape including a center electrode 120b and a lower electrode 120c connected to the center electrode 120b and protruding toward the lower chamber 60, of the hybrid plasma generating device 1. can serve as a support.

An antenna 220 including unit coils constituting the inductively coupled plasma module 200 is disposed above the quartz plate 240 . At this time, the number of unit coils is not limited.

Support ball 260 to maintain a vacuum between the upper part of the lower chamber 60, that is, between the quartz plate 240 and the lower electrode rod 120c of the first electrode 120 and between the quartz plate 240 and the side outer wall can be placed. For example, the support ball 260 may be an O-ring.

The lower chamber 60 forms a reaction space in which plasma P is formed to process samples such as semiconductor wafers or glass substrates, and can perform a function of maintaining the reaction space at a vacuum and a constant temperature. A gas nozzle (not shown) for injecting a reaction gas from the outside and an exhaust port for discharging the reaction gas to the outside may be provided in the lower chamber 60 . In addition, a second electrode 140 for mounting a sample such as a semiconductor wafer or a glass substrate may be provided inside the reaction chamber 50 .

4 is a diagram showing a state in which a power module supplies power to a hybrid plasma generating device according to an embodiment of the present invention, and FIG. 5 is a view showing a variable current control module and a voltage control module according to an embodiment of the present invention. It is a drawing showing how the capacitor is arranged.

Referring to FIG. 4 , the power module 30 may be connected to the first electrode 120 , the second electrode 140 , and the antenna 220 to supply power.

First, the plasma generated by the capacitive coupled plasma module 100 will be described. When RF power is applied to the first electrode 120 and the second electrode 140 constituting the capacitive coupled plasma module 100, the first An electric field is induced between the electrode 120 and the second electrode 140 . At the same time, when the reaction gas is injected through a gas injection port (not shown) installed on the outer wall of the side of the hybrid plasma generator 1, the reaction gas can be transformed into a plasma state by the induced electric field inside the lower chamber 60. . At this time, a chemical reaction occurs between neutral radical particles generated therefrom and charged ions, and the surface of the substrate is etched or deposited.

In the case of the inductively coupled plasma module 200, RF power may be supplied from the power module 30, and an antenna 220 including unit coils may generate an electric field. The electric field generated in this way generates a discharge in the reaction gas injected through the gas injection port (not shown) to turn the gas into plasma and causes a chemical reaction between the neutral radical particles and charged ions generated from the gas to form a substrate. Surface treatment may be performed, and at this time, the power module 30 is applied to the first electrode 120 and the second electrode 140 of the capacitive coupled plasma module 100 and the antenna of the inductively coupled plasma module 200. Different frequencies may be applied to 220 respectively.

In addition, the hybrid plasma generating device 1 is a current control module (a 10) and a voltage control module 20 connected to the lower part 220b of the antenna of the inductively coupled plasma module 200 to control the magnitude of the voltage applied to the inductively coupled plasma module 200. The current control module 10 and the voltage control module 20 may include variable capacitors C1 and C2, respectively, and the capacitance of the variable capacitors C1 and C2 is measured in real time by the control module 40. Variable and controllable.

In addition, as shown in FIGS. 4 and 5, one side of the current control module 10 is connected to the upper antenna 220a, which is the input end of the antenna, and the other side of the current control module 10 is connected to the inductively coupled plasma module 200. ), and one side of the voltage control module 20 is connected to the lower antenna 220b, which is the output end of the antenna, and the other side of the voltage control module 20 generates hybrid plasma. It may be connected to the grounding part (G) of the device.

Specifically, since the first capacitor C1 of the current control module 10 is electrically connected to the power module 30 and the capacitively coupled plasma module 100, the control module 40 has a first capacitor C1 It is possible to control the magnitude of the current flowing through the antenna 220 of the inductively coupled plasma module 200 and the electrode of the capacitively coupled plasma module 100 by varying the capacitance value of . Accordingly, in the case of the present invention, it is possible to generate a desired type of plasma source by adjusting the size of the current flowing through the capacitively coupled plasma module 100 and the inductively coupled plasma module 200, and in some cases simultaneous use and control can be made possible.

In addition, since the second capacitor C2 of the voltage control module 20 is connected to the ground part G of the hybrid plasma generator, the control module 40 varies the capacitance value of the second capacitor C2. In this way, the magnitude of the voltage applied to the antenna 220 of the inductively coupled plasma module 200 can be controlled.

Specifically, in the control module 40, the other side of the second capacitor C2 is connected to the ground G, so that a voltage balance condition can be formed by adjusting the capacitance value. The voltage balance condition refers to the antenna 220 ) means that the same magnitude of voltage is applied to the input terminal and the output terminal, and the phase is opposite. The voltage balance condition may mean a case where the magnitude of the impedance of the second capacitor is half of the magnitude of the impedance of the coil of the capacitive coupled plasma module 100 .

For example, when a voltage of 10V is applied to the capacitively coupled plasma module 100, if there is no second capacitor, the output terminal of the antenna is connected to the ground (G), so the power of the input terminal of the antenna becomes 10V, and the antenna The output terminal becomes 0V. However, as in the present invention, when the second capacitor C2 grounded to the ground is connected to the lower portion 220b of the antenna, which is the output terminal of the antenna, the voltage at the output terminal of the antenna can be controlled to be -5V, and accordingly, the antenna The voltage at the input terminal of can be +5V.

In the case of having the same characteristics as the present invention, the size of the voltage itself applied to the antenna is reduced, so that problems due to capacitive coupling and sputtering generated in the capacitive coupled plasma module 200 can be reduced, There is an advantage of forming a higher density plasma, and since the capacitance values of the variable capacitors C1 and C2 can be controlled in real time by the control module 40, the plasma generated according to the user's desire There is an advantage that the amount and density can be controlled in real time.

FIG. 6 is a diagram showing the experimental results of the plasma generation density according to the change in the variable capacitor value in order to prove the effect according to the present invention. Each experimental result in FIG. , 300pF, 400pF, 600pF, and 1000pF, it is a diagram showing the density of the generated plasma.

Referring to FIG. 6 , it can be seen that the distribution and density of generated plasma change whenever the capacitance value of the second capacitor is increased. Through these results, the user can easily control the distribution and density of the generated plasma by adjusting the capacitance value of the capacitor according to the experimental environment.

The hybrid plasma generating device and the hybrid plasma generating device according to an embodiment can generate a desired type of plasma source by adjusting the amount of current flowing through the capacitively coupled plasma module and the inductively coupled plasma module using a variable capacitor. . In addition, since the magnitude of the voltage applied to the antenna can be reduced by using a variable capacitor, capacitive coupling and sputtering problems generated in the hybrid plasma generator can be reduced, so that a higher density plasma can be formed. There are advantages to

In addition, since the capacitance value of the variable capacitor can be controlled in real time by the control module, the amount and density of generated plasma can be controlled in real time according to the user's desire.

On the other hand, components, units, modules, components, etc. described in this specification described as “~ unit” may be implemented together or separately as interoperable logic devices. Depiction of different features for modules, units, etc. is intended to highlight different functional embodiments and does not necessarily mean that they must be realized by separate hardware or software components. Rather, functionality associated with one or more modules or units may be performed by separate hardware or software components or integrated within common or separate hardware or software components.

Additionally, the logic flow and structural block diagrams described in this patent document describe corresponding actions and/or specific methods supported by corresponding functions and steps supported by the disclosed structural means. It can also be used to build software structures and algorithms and their equivalents.

The present description presents the best mode of the invention and provides examples to illustrate the invention and to enable those skilled in the art to make and use the invention. The specification thus prepared does not limit the invention to the specific terms presented.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art or those having ordinary knowledge in the art do not deviate from the spirit and technical scope of the present invention described in the claims to be described later. It will be understood that the present invention can be variously modified and changed within the scope not specified. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

1: hybrid plasma generator
10: current regulation module
20: voltage regulation module
30: power module
40: control module
50: upper chamber
60: lower chamber
100: capacitive coupled plasma module
200: inductively coupled plasma module

Claims (10)

upper chamber;
a capacitively coupled plasma module disposed above the upper chamber;
an inductively coupled plasma module disposed on a side of the capacitively coupled plasma module;
a current control module connected to an upper portion of an antenna of the inductively coupled plasma module to control current flowing to the inductively coupled plasma module and including a first variable capacitor;
a voltage control module connected to a lower portion of an antenna of the inductively coupled plasma module to control a voltage applied to the inductively coupled plasma module and including a second variable capacitor; and
A control module for controlling capacitances of the first variable capacitor and the second variable capacitor; and
The control module,
Controlling the size of the capacitance of the second variable capacitor so that the phases of the voltages at the input terminal and the output terminal of the antenna are opposite to each other and the magnitudes of the voltages are equal to each other, the hybrid plasma generator. According to claim 1,
One side of the current control module is connected to the top of the antenna,
The other side of the current control module is connected to a power module for supplying power to the inductively coupled plasma module, hybrid plasma generating device. According to claim 1,
One side of the voltage control module is connected to the lower part of the antenna,
The other side of the voltage control module is connected to the ground of the hybrid plasma generating device. delete delete According to claim 1,
The control module,
Controlling the size of the capacitance of the first variable capacitor to control the size of the current flowing through the antenna of the inductively coupled plasma module and the electrode of the capacitively coupled plasma module. According to claim 1,
The control module,
Controlling the size of the voltage applied to the antenna of the inductively coupled plasma module by controlling the size of the capacitance of the second variable capacitor. delete A method for controlling a hybrid plasma generating device including a capacitively coupled plasma module and an inductively coupled plasma module,
controlling a current flowing into the inductively coupled plasma module using a first variable capacitor connected to an upper portion of an antenna of the inductively coupled plasma module; and
Controlling the magnitude of the voltage applied to the inductively coupled plasma module using a second variable capacitor connected to a lower portion of an antenna of the inductively coupled plasma module;
The step of controlling the magnitude of the voltage,
Controlling the size of the capacitance of the second variable capacitor so that the phases of the voltages of the input terminal and the output terminal of the antenna are opposite to each other and the magnitudes of the voltages are equal to each other. delete

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