KR102636459B1 - Plasma reactor having cavity structure - Google Patents

Abstract

The present invention relates to a plasma reactor having a cavity structure. The plasma reactor according to an embodiment of the present invention includes a reactor body forming a plasma discharge space and a groove-shaped cavity at the center, and connected to one side of the reactor body. It includes a gas inlet connected to the reactor body, a gas outlet connected to the other side of the reactor body, and a ferrite core at least partially located in the cavity.

Description

Plasma reactor having a cavity structure {PLASMA REACTOR HAVING CAVITY STRUCTURE}

The present invention relates to a plasma reactor having a cavity structure. Specifically, the cavity structure is formed in the center of the reactor body, and a ferrite core is placed inside the cavity to form plasma in the plasma discharge space of the reactor body to generate plasma. It relates to a plasma reactor having a cavity structure to prevent particle generation.

Plasma discharge is used for gas excitation to generate active gases containing ions, free radicals, atoms, and molecules. Activated gases are widely used in various fields, and are typically used in a variety of semiconductor manufacturing processes, such as etching, deposition, cleaning, and ashing.

Recently, wafers and LCD glass substrates for manufacturing semiconductor devices are becoming larger. Therefore, there is a demand for an easily expandable plasma source that has a high control capability for plasma ion energy and a large-area processing capability. The use of remote plasma is known to be very useful in the semiconductor manufacturing process using plasma.

For example, it is useful in cleaning process chambers or in the ashing process for photoresist strips. However, as the size of the substrate to be processed increases, the volume of the process chamber also increases, and a plasma source that can sufficiently remotely supply high-density active gas is required.

Meanwhile, remote plasma reactors (or remote plasma generators) include those using a transformer coupled plasma source and those using an inductively coupled plasma source. A remote plasma reactor using a transformer coupled plasma source has a structure in which a magnetic core having a primary winding coil is mounted on a toroidal reactor body. A remote plasma reactor using an inductively coupled plasma source has a structure in which an inductively coupled antenna is mounted on a reactor body of a hollow tube structure.

In the case of a remote plasma reactor with a transformer-coupled plasma source, due to its nature, it operates in a relatively high pressure atmosphere, so it is difficult to ignite the plasma or maintain the ignited plasma in a low pressure atmosphere. In the case of a remote plasma reactor with an inductively coupled plasma source, it is possible to operate in a relatively low pressure atmosphere due to its characteristics, but in order to operate in a high pressure atmosphere, the supplied power must be increased. However, in this case, the interior of the reactor body may be damaged by ion bombardment.

However, remote plasma reactors that operate efficiently at low or high pressure are required according to the various requirements of the semiconductor manufacturing process, but conventional remote plasma reactors employing either a coupled plasma source or an inductively coupled plasma source cannot respond appropriately. .

The purpose of the present invention is to form a cavity structure in the hollow part of the reactor body, and to form a plasma in the plasma discharge space of the reactor body by placing a ferrite core inside the cavity, thereby forming a cavity structure to prevent particle generation during plasma generation. The purpose is to provide a plasma reactor.

A plasma reactor according to an embodiment of the present invention includes a reactor body that forms a plasma discharge space between an outer curved portion and an inner curved portion, and a cavity structure is formed by the inner curved portion; a gas inlet connected to a plasma discharge space on one side of the reactor body; a gas outlet connected to the plasma discharge space on the other side of the reactor body; A plasma source for positioning a ferrite core with a coil wound inside the cavity of the reactor body; and a power source that supplies power to the coil.

A plasma reactor according to another embodiment of the present invention includes a reactor body that forms a plasma discharge space between an outer curved portion and an inner curved portion, and a cavity structure is formed by the inner curved portion; a gas inlet connected to a plasma discharge space on one side of the reactor body; a gas outlet connected to the plasma discharge space on the other side of the reactor body; A plasma source that positions a ferrite core with a first surface electrode wound inside the cavity of the reactor body and winds a second surface electrode along an outer curved surface of the reactor body; and a power source that supplies power to the surface electrode.

The first and second surface electrodes are formed by a current path provided at a predetermined number of turns to form inductively coupled plasma in the plasma discharge space.

The first and second surface electrodes are composed of a copper plate and an insulating member, and the copper plate is insulated by the insulating member.

The reactor body has a reverse bell-shape, with a longitudinal cross-section that is donut-shaped and a transverse cross-section that is U-shaped.

The reactor body is composed of dielectric material.

It further includes a gas distribution unit having a baffle structure for uniformly distributing the gas supplied through the gas inlet within the plasma discharge space.

The present invention forms a cavity structure in the hollow part of the reactor body and places a ferrite core inside the cavity to form plasma in the plasma discharge space of the reactor body, thereby preventing particle generation during plasma generation.

The present invention can provide a remote plasma reactor that operates efficiently at low or high pressure according to the various needs of the semiconductor manufacturing process.

1 is a block diagram showing the overall configuration of a plasma reactor having a cavity structure of the present invention and a plasma processing system equipped therewith;
Figure 2 is a perspective view of a plasma reactor according to an embodiment of the present invention;
Figure 3 is a longitudinal cross-sectional view taken along line A-A' of the plasma reactor of Figure 2;
Figure 4 is a transverse cross-sectional view taken along line B-B' of the plasma reactor of Figure 2;
Figure 5 is a perspective view showing an example of a ferrite core mounted in the plasma reactor of Figure 2;
Figure 6 is a cross-sectional view of the plasma reactor of Figure 5;
Figure 7 is a perspective view showing another embodiment of the ferrite core mounted in the plasma reactor of Figure 2;
Figure 8 is a cross-sectional view of the plasma reactor of Figure 7;
9 is a perspective view of a plasma reactor according to another embodiment of the present invention;
Figure 10 is a longitudinal cross-sectional view taken along line A-A' of the plasma reactor of Figure 9;
Figure 11 is a transverse cross-sectional view taken along line B-B' of the plasma reactor of Figure 9;
Figure 12 is a diagram of a gas distribution unit applied to Figure 1;
Figures 13 to 15 are cross-sectional views taken along line C-C' of the gas distribution part of Figure 12.

In order to fully understand the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below. This example is provided to more completely explain the present invention to those with average knowledge in the art. Therefore, the shapes of elements in the drawings may be exaggerated to emphasize a clearer description. It should be noted that identical members in each drawing may be indicated by the same reference numerals. Detailed descriptions of well-known functions and configurations that are judged to unnecessarily obscure the gist of the present invention are omitted.

1 is a block diagram showing the overall configuration of a plasma reactor having a cavity structure of the present invention and a plasma processing system equipped therewith.

Referring to FIG. 1, a plasma reactor 10 (hereinafter referred to as “plasma reactor”) having a cavity structure of the present invention is provided with a reactor body 11 that provides a plasma discharge space 24. The reactor body 11 has a gas inlet 12 and a gas outlet 16. The gas outlet 16 is connected to the chamber gas inlet 47 of the process chamber 40 through an adapter 48. The plasma gas generated in the plasma reactor 10 is supplied to the process chamber 40 through the adapter 48.

The reactor body 11 may have a reverse bell-shape in which the longitudinal cross-section is donut-shaped and the transverse cross-section is U-shaped. Here, the reactor body 11 may have a cavity structure at its center when viewed in a longitudinal cross-section. That is, the reactor body 11 has a hemispherical shape with the curved portion facing downward and an empty hollow portion, thereby forming a body having an outer region in contact with the outside and an inner region forming a cavity space. Additionally, the plasma discharge space 24 can be formed in the space between the outer area and the inner area.

The reactor body 11 may form a plasma discharge space 24 between the hemispherical outer curved surface and the inner curved surface in an area excluding the plasma hollow cavity 23.

The plasma reactor 10 is installed outside the process chamber 40 and remotely supplies plasma to the process chamber 40. The plasma source 20 is inductively coupled to the plasma generated in the plasma reactor 10. The plasma source 20 may include a ferrite core 21 around which a coil 22 is wound. The ferrite core 21 around which the coil 22 is wound may be located in the hollow cavity 23 of the reactor body 11.

The process chamber 40 is provided with a substrate support 42 inside to support the substrate to be processed 44 . The substrate support 42 may be electrically connected to one or more bias power sources 70 and 72 through an impedance matcher 74. The adapter 48 may have an insulating section for electrical insulation and a cooling channel to prevent overheating.

The process chamber 40 may be provided with a baffle 46 therein for distributing plasma gas between the substrate support 42 and the chamber gas inlet 47. The baffle 46 allows the plasma gas introduced through the chamber gas inlet 47 to be uniformly distributed and spread to the substrate to be processed. The substrate to be processed 44 is, for example, a silicon wafer substrate for manufacturing semiconductor devices or a glass substrate for manufacturing liquid crystal displays, plasma displays, etc.

The plasma source 20 operates by receiving radio frequencies from the power supply 30. The power supply 30 includes an AC switching power supply 32, a control circuit 33, and a voltage supply 31 that include one or more switching semiconductor devices and generate radio frequencies. Includes. The one or more switching semiconductor devices include, for example, one or more switching transistors. The voltage supply source 31 converts the alternating current voltage input from the outside into constant voltage and supplies it to the alternating current switching power supply source 32. The alternating current switching power supply 32 operates under the control of the control circuit 33 and generates radio frequencies.

The control circuit 33 controls the operation of the alternating current switching power supply 32 to control the voltage and current of the radio frequency. Control of the control circuit 33 is performed based on electrical or optical parameter values related to at least one of the plasma source 20 and the plasma generated inside the reactor body 11. For this purpose, the control circuit 33 is equipped with measurement circuits 13 and 14 for measuring electrical or optical parameter values. For example, the measurement circuit for measuring the electrical and optical parameters of the plasma includes a current probe 13 and an optical detector 14. The measurement circuits 13 and 14 for measuring the electrical parameters of the plasma source 20 measure the driving current, driving voltage, average power and maximum power of the plasma source 20, and the voltage generated from the voltage source 31. do.

The control circuit 33 controls the alternating current switching power source 32 by continuously monitoring the relevant electrical or optical parameter values through the measurement circuits 13 and 14 and comparing the measured values with reference values based on normal operation. Controls the voltage and current of radio frequencies. Although not specifically shown, the power supply source 30 is provided with a protection circuit to prevent electrical damage that may occur due to an abnormal operating environment. The power supply source 30 is connected to a system control unit 60 that controls the overall plasma processing system. The power supply source 30 provides operating status information of the plasma reactor 10 to the system control unit 60. The system control unit 60 controls the operation of the plasma reactor 10 and the process chamber 40 by generating a control signal to control the overall operation process of the plasma processing system.

The plasma reactor 10 and the power source 30 have a physically separate structure. That is, the plasma reactor 10 and the power source 30 are electrically connected to each other by a radio frequency supply cable 35. This separation structure of the plasma reactor 10 and the power source 30 provides ease of maintenance and installation. However, the plasma reactor 10 and the power source 30 may be provided as an integrated structure.

FIG. 2 is a perspective view of a plasma reactor according to an embodiment of the present invention, FIG. 3 is a longitudinal cross-sectional view along line A-A' of the plasma reactor of FIG. 2, and FIG. 4 is a perspective view of the plasma reactor of FIG. 2. This is a transverse cross-sectional view along line B-B'.

2 to 4, the plasma reactor 10 has a plasma discharge space 24 and a reactor body 11 having a gas inlet 12 and a gas outlet 16.

The reactor body 11 may have a gas inlet 12 at the top and a gas outlet 16 at the bottom. One or more gas inlets 12 may be formed in the reactor body 11, and may be formed in a distribution structure in which gas supplied from one gas source (not shown) is evenly distributed. Since the plasma discharge space 24 has a donut shape in longitudinal cross-section, it is desirable to install the gas inlet 12 on one side and connect it to the gas inlet 12 through a gas distribution structure to prevent uneven gas supply. Here, a left-right symmetrical gas distribution structure (i.e., a gas distribution structure with inlets in phases of 0° and 180°) is shown, but the present invention is not limited thereto. Meanwhile, the gas outlet 16 is formed in a structure that converges the plasma discharge space 24 (that is, a structure located on an extension of the position where the cavity 23 is formed, the central part in the longitudinal cross-section), forming a process chamber ( 40).

If the reactor body 11 is made of a metal material (such as Al), it may have an electrically insulating section in the transverse direction and may be made of a dielectric material such as quartz or aluminum nitride (AlN). Alternatively, it can be constructed using appropriate alternative materials.

The ferrite core 21 may be wound with a coil 22. The ferrite core 21 may be wound with a coil 22 and positioned inside the cavity 23 of the reactor body 11. At this time, one side of the coil 22 is connected to the power supply source 30 and the other side is grounded. The coil 22 is in the form of a pipe and may be provided with a cooling channel (not shown) inside the pipe to prevent overheating.

When power is supplied from the power source 30 to the ferrite core 21 on which the coil 22 is wound, the magnetic field H penetrating the inside of the plasma discharge space 24 of the reactor body 11 is focused. The magnetic field (H) formed by the ferrite core 21 generates an electric field (E) inside the plasma discharge space 24 provided by the reactor body 11. Therefore, inductively coupled plasma is formed in the internal plasma discharge space 24 of the reactor body 11.

FIG. 5 is a perspective view showing an example of a ferrite core mounted on the plasma reactor of FIG. 2, FIG. 6 is a cross-sectional view of the plasma reactor of FIG. 5, and FIG. 7 is a cross-sectional view of the ferrite core mounted on the plasma reactor of FIG. 2. It is a perspective view showing another example of a ferrite core, and FIG. 8 is a cross-sectional view of the plasma reactor of FIG. 7.

Since the description of the components of the plasma reactor 10 in FIGS. 5 to 8 is redundant as described above, detailed description will be omitted.

Referring to FIGS. 5 and 6, the plasma reactor 10 can be equipped with a cylindrical ferrite core 21a surrounding the outer peripheral surface of the reactor body 11 separately from the ferrite core 21 in order to improve the efficiency of plasma processing. there is. At this time, the cylindrical ferrite core 21a is wound with a coil 22a.

Referring to FIGS. 7 and 8, the plasma reactor 10 is not only located in the cavity of the reactor body 11 to improve the efficiency of plasma processing, but is also an integrated structure surrounding the outer circumferential surface and has an 'm' shape. A shaped ferrite core (21b) can be installed. At this time, the m-shaped ferrite core 21b has a first coil 22b-1 wound on the outer peripheral side and a second coil 22b-2 wound on the cavity side. That is, the m-shaped ferrite core 21b is divided into a part inserted into the cavity and a part surrounding the outer peripheral surface, and the first coil 22b-1 and the second coil 22b-2 are wound on these, respectively. The gas inlet 12 penetrates the m-shaped ferrite core 21b and is connected to the reactor body 11.

Meanwhile, referring to FIG. 6, the power supply 30 that supplies power to the coil 22a wound on the cylindrical ferrite core 21a is the power supply that supplies power to the coil 22 wound on the ferrite core 21. It may be a different power source or the same power source as the source. The coil 22 wound around the ferrite core 21 and the coil 22a wound around the cylindrical ferrite core 21a may be connected to the power supply 30 in parallel or in series.

Likewise, referring to FIG. 8, the power supply source 30 that supplies power to the second coil 22b-2 wound on the cavity side supplies power to the first coil 22b-1 wound on the outer peripheral surface. It may be a different power source or the same power source. The first coil 22b-1 wound on the outer peripheral side and the second coil 22b-2 wound on the cavity side may be connected to the power supply source 30 in parallel or in series.

FIG. 9 is a perspective view of a plasma reactor according to another embodiment of the present invention, FIG. 10 is a longitudinal cross-sectional view along line A-A' of the plasma reactor of FIG. 9, and FIG. 11 is a perspective view of the plasma reactor of FIG. 9. This is a transverse cross-sectional view along line B-B'.

9 to 11, the plasma reactor 10-1 includes a reactor body 11-1 having a plasma discharge space 24-1, a gas inlet 12-1, and a gas outlet 16-1. is provided. A detailed description of this will be omitted as it overlaps with what was explained previously.

The ferrite core 21-1 may be located inside the cavity 23-1 of the reactor body 11-1, that is, on the inner curved portion of the reactor body 11-1.

The first surface electrode 22-1 may be wound and mounted along the outer area of the reactor body 11-1, and the second surface electrode 22-2 may be wound around the ferrite core 21-1. It can be sung. The first and second surface electrodes 22-1 and 22-2 may be composed of a copper plate 22-1a and an insulating member 22-1b that insulates the copper plate 22-1a. Here, the insulating member 22-1b may be, for example, Teflon, ceramic, etc. The first and second surface electrodes 22-1 and 22-2 may be connected to the power supply 30 in parallel or in series.

The electric field E1 is directed to the plasma discharge space 24-1 of the reactor body 11-1 by the potential difference generated between the first and second electrodes 22-1 and 22-2. provided. In addition, the magnetic field H1 formed by the current path provided by the surface electrode 22-1 with a predetermined number of turns (for example, two turns, etc.) is focused on the reactor body 11-1. At this time, the magnetic field H1 forms an electric field E2 inside the plasma discharge space 24-1 provided by the reactor body 11-1. Therefore, a complex of capacitively coupled and inductively coupled plasma is formed in the internal plasma discharge space 24-1 of the reactor body 11-1. In this case, the plasma reactor 10-1 can reduce particle generation by providing a hybrid plasma source that generates a mixture of inductively coupled plasma and transformer coupled plasma.

If the reactor body 11 is made of a metal material (Al, etc.), it may have an electrically insulating section in the transverse direction, or the entire outer and inner regions may be covered with an insulating member. Additionally, the reactor body 11 may be made of a dielectric material such as quartz or aluminum nitride (AlN). Alternatively, it can be constructed using appropriate alternative materials.

FIG. 12 is a diagram of the gas distribution unit applied to FIG. 1, and FIGS. 13 to 15 are cross-sectional views taken along line C-C' of the gas distribution unit of FIG. 12.

Referring to FIG. 12 , the plasma reactor 10 may include a gas distribution unit 15 at the top of the reactor body 11 . The gas distribution unit 15 has a baffle structure for uniformly distributing the gas supplied through the gas inlet 12 within the plasma discharge space. The gas distribution unit 15 is detachable from the reactor body 11 to facilitate maintenance.

13 to 15 show a baffle structure that uniformly distributes gas in the gas distribution unit 15. Gas flow paths 15a to 15c are formed for uniform gas distribution throughout the gas distribution unit 15.

In FIG. 13, the gas flow path 15a of the gas distribution unit 15 may be uniformly distributed with the same size overall. In FIG. 14 , the gas flow path 15b of the gas distribution unit 15 may uniformly distribute flow paths of the same size as the gas flow path 15a of FIG. 9 , but may have various shapes. In FIG. 15, the gas flow path 15c of the gas distribution unit 15 is formed by forming the flow path in the area where the gas supplied from the gas inlet 12 directly touches the narrowest, and gradually widening the flow path in other areas, thereby forming the flow path. The size can be designed differently. In addition, those skilled in the art will easily understand that various types of flow paths can be formed.

The embodiments of the present invention described above are merely illustrative, and those skilled in the art will understand that various modifications and other equivalent embodiments are possible. Thus, it will be understood that the present invention is not limited to the forms mentioned in the detailed description above. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the attached patent claims. In addition, the present invention should be understood to include all modifications, equivalents and substitutes within the spirit and scope of the present invention as defined by the appended claims.

10: plasma reactor 11: reactor body
12: gas inlet 16: gas outlet
21: Ferrite core 22: Coil
23: Cavity 24: Plasma discharge space
30: power source 40: process chamber

Claims (11)

A reactor body installed outside a process chamber for processing a substrate, forming a plasma discharge space inside and forming a groove-shaped cavity in the outer center so as to remotely supply plasma to the process chamber;
a gas inlet connected to one side of the reactor body;
a gas outlet formed to be connected to the other side of the reactor body and formed in a direction opposite to the gas inlet in the reactor body;
a ferrite core positioned so that at least a portion is inserted into the cavity; and
It includes; a first coil formed to surround at least a portion of the circumference of the ferrite core;
The cavity is,
It is located based on a line connecting the gas inlet and the gas outlet, and is formed in the shape of a groove in the direction in which the gas inlet is located,
The ferrite core is,
A plasma reactor including a plasma source coupled to the cavity so that a magnetic field can be formed in the same direction as the direction in which gas flows in the plasma discharge space, and inserted and coupled in a direction from the gas inlet to the gas outlet. delete According to paragraph 1,
The ferrite core is,
A plasma reactor having a bar shape and located in the cavity. According to paragraph 1,
The ferrite core is,
A plasma reactor having an 'm' shape and a central protruding portion located in the cavity. According to paragraph 1,
The plasma source is,
A plasma reactor including a second coil located on an outer peripheral surface opposite the cavity of the reactor body. According to paragraph 1,
The plasma source is,
At least one first surface electrode located within a cavity of the reactor body;
At least one second surface electrode located on the outer peripheral surface opposite to the cavity of the reactor body;
Including, a plasma reactor. According to one of paragraphs 1,
The plasma source is,
a second coil located on the outer circumferential surface opposite the cavity of the reactor body;
At least one first surface electrode located within a cavity of the reactor body; and
At least one second surface electrode located on the outer peripheral surface opposite to the cavity of the reactor body;
Including,
A plasma reactor wherein at least one of the first coil, the second coil, the first surface electrode, and the second surface electrode is wound around the ferrite core. According to paragraph 1,
The gas inlet is,
An inlet for injecting gas; and
Distributing gas into two or more paths based on the inlet, and comprising a distribution pipe where each of the two or more paths is coupled to the reactor body,
A plasma reactor wherein the gas inlet has a Y-shape. According to paragraph 1,
The reactor body is,
The diameter of the outer peripheral surface decreases in at least some sections based on the direction from the uppermost end where the gas inlet is connected to the lowermost end where the gas outlet is connected,
A plasma reactor having a shape in which at least some of the uppermost corners are rounded. According to paragraph 1,
The reactor body is,
A plasma reactor whose longitudinal cross-section is donut-shaped and whose transverse cross-section is U-shaped with a reverse bell-shape. According to paragraph 1,
A plasma reactor in which the inner diameter of the gas inlet is relatively small compared to the inner diameter of the gas outlet.