KR100753869B1 - Compound plasma reactor - Google Patents

Abstract

A complex plasma reactor is provided to adjust easily production of plasma and plasma ion energy in a vacuum chamber through capacitive and inductive coupling. A vacuum chamber(100) has a substrate supporter, on which a substrate(112) is put on the substrate supporter. A dielectric window(130) is installed on an upper portion of the vacuum chamber, and is provided at its center with an opening. A gas shower head(140) is installed in the opening of the dielectric window. A RF antenna(151) is installed on an upper portion of the dielectric window around the gas shower head. The gas shower head and the substrate supporter are capacitively coupled to a plasma in the vacuum chamber, while the RF antenna is inductively coupled to the plasma.

Description

Compound Plasma Reactor {COMPOUND PLASMA REACTOR}

In order to more fully understand the drawings used in the detailed description of the invention, a brief description of each drawing is provided.

1 is a cross-sectional view of a hybrid plasma reactor according to a first embodiment of the present invention.

FIG. 2 is a view illustrating an assembly structure of a radio frequency antenna and a gas shower head installed on the plasma reactor of FIG. 1.

3 is a diagram illustrating an electrical connection structure between a radio frequency antenna and a shower head.

4A to 4D illustrate various examples of modifications of an electrical connection structure between a radio frequency antenna and a shower head.

5 is a diagram illustrating an example in which a dual power supply structure by power division is adopted.

6 is a diagram illustrating an example in which a dual power supply structure using two power supply sources is adopted.

7A and 7B are diagrams illustrating a power control unit configured between a radio frequency antenna and ground.

8 is a cross-sectional view of a plasma reactor according to a second embodiment of the present invention.

FIG. 9 is a view illustrating an arrangement structure of a radio frequency antenna and a gas shower head installed on the plasma reactor of FIG. 10.

FIG. 10 is a diagram illustrating an example in which a cylindrical radio frequency antenna is installed in the outer sidewall portion of the vacuum chamber.

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

100: vacuum chamber 110; Lower body

111: substrate support 112: substrate to be processed

113: vacuum pump 120: top cover

121: gas inlet 123: upper space

130: dielectric window 132: dielectric wall

140: gas shower head 151: radio frequency antenna

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio frequency plasma reactor, and in particular, having a complex plasma generating structure for generating inductively and capacitively coupled plasma by radio frequency. The present invention relates to a combined plasma reactor.

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, and 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 due to ion bombardment, radio frequency power is limited.

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.

As the 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 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.

Accordingly, the present invention is to solve the above-mentioned problems, the object of the present invention is to adopt both the advantages of the inductively coupled plasma and capacitively coupled plasma has a high controllability to plasma ion energy and can generate a more uniform high-density plasma It is to provide a composite plasma reactor.

One aspect of the present invention for achieving the above technical problem relates to a complex plasma source. The hybrid plasma reactor of the present invention comprises: a vacuum chamber having a substrate support on which a substrate to be processed is placed; A dielectric window installed at an upper portion of the vacuum chamber and having an opening at a central portion thereof; A gas shower head installed in the opening of the dielectric window; And a radio frequency antenna installed above the gas shower head above the dielectric window, wherein the gas shower head and the substrate support are capacitively coupled to the plasma inside the vacuum chamber, and the radio frequency antenna is connected to the plasma inside the vacuum chamber. Inductively coupled.

In this embodiment, a Faraday shield is provided between the radio frequency antenna and the dielectric window.

In this embodiment, a first power supply connected to a radio frequency antenna for supplying a radio frequency; And a second power source for supplying radio frequencies to the substrate support.

In this embodiment, a third power supply source for supplying a radio frequency of a frequency different from that of the second power supply source to the substrate support is included.

In this embodiment, a first power supply for supplying a radio frequency; And a power divider that divides the radio frequency power provided from the first power supply and divides and supplies the radio frequency power to the radio frequency antenna and the substrate support.

In this embodiment, the substrate support includes a second power supply for supplying a radio frequency of a frequency different from the radio frequency of the first power supply.

In this embodiment, a power regulator is connected between the radio frequency antenna and ground or at least one of the gas shower head and ground.

In this embodiment, the radio frequency antenna and the gas shower head are connected in series between a first power source and ground, wherein either end of the radio frequency antenna is connected to ground or the gas shower head is connected to ground. Connected with branches.

In this embodiment, a power regulator is connected between the radio frequency antenna and ground or at least one of the gas shower head and ground.

In this embodiment, the radio frequency antenna has two or more separate structures, and the two or more separate radio frequency antennas and the gas shower head are connected in series between the first power source and the ground, and any two separate A gas shower head is connected between the radio frequency antennas.

In this embodiment, a power regulator is connected between the radio frequency antenna and ground or at least one of the gas shower head and ground.

In this embodiment, the dielectric window and the radio frequency antenna are installed inside the vacuum chamber and include a top cover covering the top of the vacuum chamber.

Following this embodiment, the dielectric window serves as the top cover of the vacuum chamber and includes a cover member that entirely covers the radio frequency antenna on top of the dielectric window.

Following this embodiment, a dielectric wall is installed along the inner wall of the vacuum chamber.

In this embodiment, the shower head comprises a silicon plate that abuts the interior region of the vacuum chamber and is formed with a plurality of gas injection holes.

The 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 by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape of the elements in the drawings and the like are exaggerated to emphasize a clearer description. In understanding the drawings, it should be noted that like parts are intended to be represented by the same reference numerals as much as possible. And detailed description of known functions and configurations that are determined to unnecessarily obscure the subject matter of the present invention is omitted.

(Example)

Hereinafter, with reference to the accompanying drawings illustrating a preferred embodiment of the present invention, it will be described in detail the hybrid plasma reactor of the present invention. In addition, in the drawings, the same reference numerals are denoted together for components that perform the same function.

1 is a cross-sectional view of a hybrid plasma reactor according to a first embodiment of the present invention.

Referring to FIG. 1, the hybrid plasma reactor includes a vacuum chamber 100 including a lower body 110 and an upper cover 120. The substrate support 111 on which the substrate to be processed 112 is placed is provided in the vacuum chamber 100. The lower body 110 is provided with a gas outlet 113 for gas exhaust, the gas outlet 113 is connected to the vacuum pump 115. The substrate 112 to be processed is, for example, a silicon wafer substrate for producing a semiconductor device or a glass substrate for producing a liquid crystal display or a plasma display.

The lower body 110 is made of a metallic material such as aluminum, stainless steel, or copper. Or coated metal, for example anodized aluminum or nickel plated aluminum. Or refractory metal. Alternatively, it is possible to rewrite the lower body 110 entirely with an electrically insulating material such as quartz, ceramic, or other materials suitable for the intended plasma process to be performed. The upper cover 120 and the lower body 110 may be made of the same material or different materials.

The inner side of the vacuum chamber 100 is provided with a dielectric window 130 having a central opening. The gas shower head 140 is installed in the opening of the dielectric window 130. The gas shower head 140 includes at least one gas distribution plate 145 and is made of a conductive material. The gas shower head 140 may be provided with a silicon flat plate 146 having a plurality of gas injection holes formed at portions in contact with the inner region of the vacuum chamber 100. The gas inlet 121 connected to the gas shower head 140 is installed at the center of the upper cover 120. The radio frequency antenna 151 is installed in the upper space 123 between the upper cover 120 and the dielectric window 130.

A dielectric wall 132 may optionally be installed along the inner wall of the vacuum chamber 100. Dielectric wall 132 and dielectric window 130 preferably have an integral structure. However, they can be configured as separate structures. The dielectric wall 132 is installed to a portion slightly lower than the substrate support 111 as a whole to prevent the lower body 110 from being damaged or contaminated during the process. Dielectric window 130 and dielectric wall 132 are comprised of an insulating material, such as, for example, quartz or ceramic.

The dielectric window 130 may have a structure spanning between the upper cover 120 and the lower body 110, and each bonding surface is provided with O-rings 114 and 122, respectively, for vacuum insulation. In addition, O-rings 125 and 124 for vacuum insulation are installed on the joint surface of the dielectric window 130 and the shower head 140 and the joint surface of the shower head 140 and the upper cover 120, respectively.

FIG. 2 is a view illustrating an assembly structure of a radio frequency antenna and a gas shower head installed on the plasma reactor of FIG. 1. Referring to FIG. 2, the radio frequency antenna 151 is installed in a flat spiral structure around the gas shower head 140. A Faraday shield 142 is provided between the dielectric window 130 and the radio frequency antenna 151. The Faraday shield 142 may or may not be installed in an optional configuration. The Faraday shield 142 may or may not have an electrical connection with the gas shower head 140.

Again, referring to FIG. 1, one end of the radio frequency antenna 151 is electrically connected to the first power supply 160 supplying the radio frequency through the impedance matcher 161 and the other end is grounded. The radio frequency antenna 151 is inductively coupled to the internal plasma of the vacuum chamber. The substrate support 111 is electrically connected to the second power supply 162 supplying the radio frequency through the impedance matcher 163 and the gas shower head 140 is grounded. The gas shower head 140 and the substrate support 111 constitute a pair of capacitive electrodes and are capacitively coupled to the plasma inside the vacuum chamber 100. The first and second power sources 160 and 162 may be configured using a radio frequency power source capable of controlling the output voltage without a separate impedance matcher. The phase relationship between the radio frequency signal for capacitive coupling and the radio frequency signal for inductive coupling has an appropriate relationship, for example, a phase relationship of about 180 degrees.

In the hybrid plasma reactor according to the first embodiment of the present invention, the gas shower head 140 and the substrate support 111 are capacitively coupled to the plasma inside the vacuum chamber 100, and the radio frequency antenna 151 ) Is inductively coupled to the plasma inside the vacuum chamber 100. In general, inductively coupled plasma sources using radio frequency antennas are affected by plasma density and uniformity depending on the shape of the radio frequency antenna. In this regard, the plasma reactor of the present invention includes a gas shower head 140 that is capacitively coupled to the central portion, and has a radio frequency antenna 151 arranged in a spiral shape around the plate, thereby making it more uniform in the vacuum chamber. A plasma can be obtained.

This capacitive and inductive coupling facilitates the precise control of plasma generation and plasma ion energy in the vacuum chamber 100. This maximizes process productivity. In addition, since the gas shower head 140 is positioned above the substrate support 111, uniform gas injection may be performed on the substrate 112 to be processed to further improve uniform substrate processing.

3 is a diagram illustrating an electrical connection structure between a radio frequency antenna and a shower head. Referring to FIG. 3, the radio frequency antenna 151 and the gas shower head 140 may be electrically connected in series. That is, one end of the radio frequency antenna 151 is connected to the first power supply 160 through the impedance matcher 161, and the other end is connected to the gas shower head 140. And the gas shower head 140 is grounded. The electrical connection relationship between the gas shower head 140 and the radio frequency antenna 151 may be variously modified as follows.

4A to 4D illustrate various examples of modifications of an electrical connection structure between a radio frequency antenna and a shower head. 4A to 4D show a relationship between the physical arrangement of the radio frequency antenna 151 and the gas shower head 140 and an electrical connection relationship, as shown in (b) in FIG. The connection relationship is shown by electrical symbols.

The method of connecting the gas shower head 140 and the radio frequency antenna 151 illustrated in FIG. 4A is described with reference to FIG. 4. One end of the radio frequency antenna 151 is electrically connected to the first power supply 160 through an impedance matcher 161, and the other end is electrically connected to the gas shower head 140. The gas shower head 140 is grounded.

In the method of connecting the gas shower head 140 and the radio frequency antenna 151 illustrated in FIG. 4B, the gas shower head 140 is first electrically connected to the first power supply 160, and then the radio frequency antenna 161 is connected. Is connected to the gas shower head 140 and grounded.

The connection method of the gas shower head 140 and the radio frequency antenna 151 illustrated in FIGS. 4C and 4D comprises the radio frequency antenna 151 as two separate antennas 151a and 151b and a gas shower therebetween. The head 140 is electrically connected. However, in FIG. 4C, the radio frequency antenna 151 has an arrangement structure in which two separate antennas 151a and 151b are wound in the same winding direction but positioned outside and located inside.

In the radio frequency antenna 151 shown in FIG. 4D, two separate antennas 151a and 151b are wound in a flat spiral around the gas shower head 140 in parallel. The outer end of one antenna 151a located at the outer side is connected to the first power supply 160 through an impedance matcher 161, and the other end is connected to the gas shower head 140. The other antenna 151b located inside the inner end is connected to the gas shower head 140, the outer end is grounded.

The electrical connection between the gas shower head 140 and the radio frequency antenna 161 illustrated in FIGS. 4A to 4D may have various electrical connection methods in addition to those illustrated. In addition, a power supply method of the radio frequency antenna 161 and the substrate support 111 may be adopted as described below. In addition, the number of power supplies for supplying a radio frequency may be variously modified.

5 is a diagram illustrating an example in which a dual power supply structure by power division is adopted. Referring to FIG. 5, a power split supply structure in which the radio frequency provided from the first power source 160 is distributed through the power distribution unit 164 and dividedly supplied to the radio frequency antenna 151 and the substrate support 111 is provided. Can be employed. The power distribution unit 164 may divide power by various methods, for example, power division using a transformer, power division using a plurality of resistors, and power division using a capacitor. The substrate support 111 is provided with a radio frequency divided from the first power source 160 and a radio frequency provided from the second power source 162, respectively. Here is the radio frequency of the different frequencies provided by the first and second power supply (160, 162).

6 is a diagram illustrating an example in which a dual power supply structure using two power supply sources is adopted. Referring to FIG. 6, the substrate support 111 may be provided with two radio frequencies through two power sources 162a and 162b providing different frequencies.

As such, when the substrate support 111 is provided with radio frequencies having different frequencies, various power supply structures such as a power split structure or an independent separate power source may be adopted. The dual power supply structure of the substrate support 111 further facilitates plasma generation inside the vacuum chamber 100, further improves plasma ion energy control on the surface of the substrate 112, and further improves process productivity. You can.

The single or dual power supply structure of the substrate support 111 is mixed with the various electrical connection methods of the radio frequency antenna 151 and the gas shower head 140 described with reference to FIGS. Can be implemented.

7A and 7B are diagrams illustrating a power control unit configured between a radio frequency antenna and ground. 7A and 7B, a power controller 170 may be configured between the radio frequency antenna 151 and the ground. The power controller 170 may be configured of, for example, a variable capacitor 171a or a variable inductor 171b. The inductive coupling energy of the radio frequency antenna 151 may be adjusted according to the variable capacitance control of the power controller 170. The power control unit 170 may be configured between the gas shower head 140 and the ground to adjust the capacitive coupling energy.

The power control unit 170 may be mixed with various power connection structures of the above-described various types of power supply structures and the gas shower head 140 and the radio frequency antenna 161 to implement more various electrical connection methods.

8 is a cross-sectional view of a plasma reactor according to a second embodiment of the present invention. FIG. 9 is a view illustrating an arrangement structure of a radio frequency antenna and a gas shower head installed on the plasma reactor of FIG. 10. 8 and 9, the plasma reactor of the second embodiment of the present invention basically has the same configuration as the first embodiment described above. Therefore, repeated description of the same configuration is omitted.

However, in the plasma reactor according to the second embodiment, the structure of the vacuum chamber 100a is slightly different from the vacuum chamber 100 of the first embodiment described above. In the vacuum chamber 100a of the plasma reactor of the second embodiment, the dielectric window 130 formed on the upper portion of the lower body 110 serves as the upper cover. The upper portion of the dielectric window 130 includes a cover member 126 covering the radio frequency antenna 151 as a whole. Cover member 126 may be constructed of a conductive or nonconductive material. The shower head 140 has a structure that protrudes to the substrate support 111 lower than the dielectric window 130.

FIG. 10 is a diagram illustrating an example in which a cylindrical radio frequency antenna is installed in the outer sidewall portion of the vacuum chamber. Referring to FIG. 10, the radio frequency antenna 151 has a flat spiral structure and is installed on an upper portion of the dielectric window 130, and may be installed in a cylinder structure on an outer sidewall portion of the vacuum chamber 100 in an extended structure. . The structure of the dielectric window 130 also has a suitable structure. In addition, the cover member also has an extended structure to cover the radio frequency antenna 151 provided in the side wall portion.

The hybrid plasma reactor according to the present invention may be variously modified and may take various forms. It is to be understood, however, that the present invention is not limited to the specific forms referred to in the above description, but rather includes all modifications, equivalents and substitutions within the spirit and scope of the invention as defined by the appended claims. It should be understood to do.

According to the hybrid plasma reactor of the present invention as described above, the gas shower head 140 and the substrate support 111 is capacitively coupled to the plasma inside the vacuum chamber 100, the radio frequency antenna 151 is Inductively coupled to the plasma inside the vacuum chamber 100. This capacitive and inductive coupling facilitates the precise control of plasma generation and plasma ion energy in the vacuum chamber 100. This maximizes process productivity. In addition, since the gas shower head 140 is positioned above the substrate support 111, uniform gas injection may be performed on the substrate 112 to be processed to further improve uniform substrate processing.

Claims (15)

A vacuum chamber having a substrate support on which a substrate to be processed is placed; A dielectric window installed at an upper portion of the vacuum chamber and having an opening at a central portion thereof; A gas shower head installed in the opening of the dielectric window; And A radio frequency antenna installed above the gas shower head above the dielectric window, The gas shower head and the substrate support are capacitively coupled to the plasma inside the vacuum chamber, and the radio frequency antenna is inductively coupled to the plasma inside the vacuum chamber. The hybrid plasma reactor of claim 1, comprising a faraday shield installed between the radio frequency antenna and the dielectric window. 2. The apparatus of claim 1, further comprising: a first power supply connected to a radio frequency antenna to supply radio frequency; And A hybrid plasma reactor comprising a second power source for supplying radio frequency to a substrate support. 4. The hybrid plasma reactor of claim 3, comprising a third power source for supplying a substrate support with a radio frequency of a frequency different from that of the second power source. 2. The apparatus of claim 1, further comprising: a first power supply for supplying a radio frequency; And And a power divider for dividing and supplying radio frequency power provided from a first power supply to a radio frequency antenna and a substrate support. 6. The hybrid plasma reactor of claim 5, comprising a second power source for supplying a radio frequency of a frequency different from the radio frequency of the first power source as a substrate support. 7. A hybrid plasma reactor according to any one of claims 3 to 6, comprising a power regulator connected between the radio frequency antenna and ground or at least one of the gas shower head and ground. The radio frequency antenna and the gas shower head of claim 3 to 6 are connected in series between a first power source and ground, A hybrid plasma reactor, wherein one end of the radio frequency antenna is connected to ground or the gas shower head is connected to ground. 9. The hybrid plasma reactor of claim 8, comprising a power regulator coupled between at least one of the radio frequency antenna and ground or between the gas shower head and ground. The radio frequency antenna according to any one of claims 3 to 6, wherein the radio frequency antenna has two or more separate structures, and the two or more separate radio frequency antennas and the gas shower head are in series between the first power source and the ground. Connected, A hybrid plasma reactor in which a gas shower head is connected between any two separate radio frequency antennas. 11. The hybrid plasma reactor of Claim 10, comprising a power regulator coupled between at least one of the radio frequency antenna and ground or between the gas shower head and ground. The hybrid plasma reactor of claim 1, wherein the dielectric window and the radio frequency antenna are installed inside the vacuum chamber and include a top cover covering the top of the vacuum chamber. The hybrid plasma reactor of claim 1, wherein the dielectric window comprises a cover member that functions as a top cover of the vacuum chamber and covers the radio frequency antenna entirely on top of the dielectric window. The hybrid plasma reactor of claim 1, further comprising a dielectric wall disposed along an inner wall of the vacuum chamber. The hybrid plasma reactor of Claim 1, wherein the shower head comprises a silicon plate in contact with an interior region of the vacuum chamber and in which a plurality of gas injection holes are formed.

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