KR20100044518A - Chemical vapor deposition apparatus - Google Patents

Abstract

PURPOSE: A chemical vapor deposition apparatus is provided to prevent the electric field offsetting between CCP source and an ICP source by arranging the CCP source between a plurality of ICP source. CONSTITUTION: A chemical vapor deposition apparatus comprises a process chamber, a susceptor, and a plurality of ICP sources and CCP sources. The susceptor is included within a process chamber. The substrate is settled in the susceptor. A plurality of ICP sources generates the plasma by inductively coupled plasma. The CCP source is included between a plurality of ICP sources. The CCP source generates the plasma by conductively coupled plasma.

Description

Chemical Vapor Deposition Apparatus {CHEMICAL VAPOR DEPOSITION APPARATUS}

The present invention relates to a chemical vapor deposition apparatus, and more particularly, to provide a chemical vapor deposition apparatus for generating an inductively coupled plasma (ICP) and a capacitively coupled plasma (CCP) will be.

Solar cells (solar cells or photovoltaic cells) are the key elements of photovoltaic power generation that converts solar energy directly into electricity. Solar cells are generally manufactured by cutting a silicon substrate (single c-Si or multi c-Si wafer). This method is excellent in terms of electricity production efficiency, which can be called the original purpose of the solar cell, but has a problem in that the production cost is high because expensive silicon substrates are excessively used. That is, the existing c-Si solar cell is manufactured to a thickness of 300 ~ 400 ㎛ due to the limitation of manufacturing technology (or cutting technology), but in fact, it is necessary to absorb the light from the solar cell to produce electricity. Since 50 micrometers of thickness is enough, the remaining silicon substrate is wasted.

In order to solve this problem, a technique of manufacturing a solar cell by forming a silicon thin film layer having a thickness of 1 to 3 μm on a low-cost substrate such as glass, metal, or plastic instead of an expensive silicon substrate is being studied. Such thin film solar cells have a large area and can be mass-produced using a technology similar to that of a conventional semiconductor device or display device, thereby improving productivity and significantly lowering manufacturing costs. As a representative example, a technology for manufacturing a solar cell by depositing an amorphous silicon (a-Si: H) thin film on an substrate in an amorphous state and crystallizing the deposited amorphous silicon thin film has been developed.

As a device for depositing a silicon thin film for manufacturing a thin film solar cell, physical vapor deposition (PVD) using physical collisions such as sputtering or chemical vapor deposition (CVD) using plasma Various types of deposition apparatuses, such as) may be used.

Conventional plasma generation methods can be divided into inductively coupled plasma (ICP) and capacitively coupled plasma (CCP) according to the application method of RF power. The former generates plasma using an induction magnetic field induced by a coil-type RF antenna, and the latter uses a vertical electric field formed by a potential difference between electrodes by applying RF power to electrodes in parallel flat plates facing each other. To generate a plasma.

Electrostatic coupling type plasma deposition apparatus can generate a plasma at low pressure, but the plasma energy is low, the ion energy and density contributing to the deposition is low. On the other hand, the inductively coupled plasma deposition apparatus has high plasma energy and improves ion energy and density contributing to the deposition, but it is difficult to generate a uniform plasma because the electric field is canceled between adjacent coil-type antennas arranged adjacently. There is a problem that it is difficult to generate a high density plasma.

Here, the deposition apparatus for manufacturing a thin film solar cell should be capable of processing a large area substrate, and should be able to process not only a circular but also various types of substrates (for example, a quadrangular substrate), and thus high density and uniformity. There is a need for the development of a deposition apparatus capable of generating plasma. In addition, glass substrates for solar cells are more susceptible to heat than silicon substrates, and thus, development of a deposition apparatus capable of depositing a thin film of excellent film quality at low temperature is required.

The present invention is to solve the above-mentioned problems, to provide a chemical vapor deposition apparatus capable of depositing a thin film on a large-area substrate for manufacturing a solar cell.

In addition, the present invention is to provide a chemical vapor deposition apparatus that improves the plasma density and uniformity to enable processing of a large area substrate.

According to embodiments of the present invention for achieving the above object of the present invention, a chemical vapor deposition apparatus capable of processing a large-area substrate is a process chamber, a susceptor provided in the process chamber, the substrate is seated, the susceptor A plurality of ICP sources provided on the top to generate plasma in an inductively coupled plasma (ICP) and a CCP source provided between the plurality of ICP sources and generating plasma in a conductively coupled plasma (CCP) It includes.

In an embodiment, the ICP source is a coil wound in a planar shape and wound such that the surface on which the coil is wound is disposed on a plane parallel to the susceptor. In addition, the plurality of ICP sources are connected in parallel or in series.

In an embodiment, the CCP source is in the form of a conductive material plate and is disposed parallel to the susceptor and the substrate.

In an embodiment, the CCP source is formed with a mount to which the ICP source is mounted. For example, the mounting portion may be formed with a hole or a slit penetrating the CCP source.

In an embodiment, the susceptor is connected to ground to correspond to the CCP source to serve as a flat electrode to generate a CCP plasma.

In an embodiment, a first power supply unit applying high frequency power to the ICP source and a second power supply unit applying high frequency power to the CCP source are provided, and a matching unit controlling the operation of the first and second power supply units. It is provided.

In an embodiment, a dielectric may be provided below the ICP source and the CCP source.

On the other hand, according to other embodiments of the present invention for achieving the above object of the present invention, a chemical vapor deposition apparatus capable of processing a large area substrate is a process chamber, a susceptor provided in the process chamber, the substrate is seated, It is provided on the susceptor to generate a plasma in the process chamber, including a plasma generating unit for generating an electrostatic coupling plasma and an inductive coupling plasma at the same time and a power supply for applying a high frequency power to the plasma generating unit; The plasma generating unit includes a CCP source having a flat plate shape parallel to the susceptor and generating a plasma by an electrostatic coupling method, and a plurality of coils mounted on the CCP source and wound in a plane shape parallel to the susceptor. Including an ICP source that generates a plasma in a coupled manner .

For example, the CCP source has a rectangular plate shape, the coil is wound in a rectangular shape, and the plurality of coils are spaced apart from each other and mounted in the CCP source.

According to the present invention, first, by placing a CCP source between a plurality of ICP sources to prevent the CCP source from canceling the electric field between the ICP source, and reinforces the reduced electric field can effectively improve the plasma generation density and uniformity have.

Second, by having a plurality of ICP sources, the density of the plasma can be generated to a degree sufficient to process a large area substrate.

Third, since it is possible to secure a high film quality and high deposition uniformity at a relatively low temperature, it is possible to process the glass substrate for solar cells.

Although the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, the present invention is not limited or restricted by the embodiments.

Hereinafter, a chemical vapor deposition apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5. For reference, Figure 1 is a longitudinal cross-sectional view for explaining a chemical vapor deposition apparatus according to an embodiment of the present invention, Figure 2 is a perspective view showing a plasma generating unit in the chemical vapor deposition apparatus of Figure 1, Figure 3 is Figure 2 As a modified embodiment of the plasma generating unit, a perspective view showing the shape of the first electrode. 4 is a block diagram illustrating a controller and a matching unit in the plasma generation unit of FIG. 2, and FIG. 5 is a graph schematically showing the magnitude of the electric field generated in the plasma generation unit of FIG. 2.

Referring to FIG. 1, the chemical vapor deposition apparatus 100 includes a process chamber 101, a susceptor 102, a power supply 104, and a plasma generator 103.

The process chamber 101 accommodates the substrate 10 to provide a space in which plasma is generated. For example, the substrate 10 is a glass substrate for a solar cell, and amorphous silicon is deposited on the surface of the substrate 10.

Hereinafter, as a chemical vapor deposition apparatus for manufacturing a solar cell, a chemical vapor deposition apparatus for a large-area glass substrate having a rectangular shape will be described as an example. However, the present invention may be applied to a silicon substrate, a metal, or a plastic substrate in addition to a glass substrate, and the shape of the substrate may be applied to a polygonal or circular substrate other than a square. In addition, the plasma generating unit 103 according to the present invention can be applied to any apparatus using a plasma, such as etching or ashing, in addition to a chemical vapor deposition apparatus.

The susceptor 102 may be provided inside the process chamber 101 so that the substrate 10 is seated, and a heater (not shown) for heating the substrate 10 for a deposition process may be provided.

The plasma generating unit 103 is provided on the susceptor 102 to generate a plasma inside the process chamber 101. For example, the plasma generator 103 is provided above the process chamber 101 and generates plasma by generating an electric field inside the process chamber 101. Alternatively, the plasma generator 103 may be provided inside the process chamber 101.

The plasma generating unit 103 generates plasma in an ICP source 131 that generates plasma in an inductively coupled plasma (hereinafter referred to as ICP) and a conductively coupled plasma (hereinafter referred to as CCP). Generating a CCP source 132. In particular, the plasma generator 103 is characterized in that the ICP and CCP are generated at the same time.

The ICP source 131 is a coil wound to form an induction magnetic field in the process chamber 101, and a first power supply unit for applying high frequency power to the ICP source 131 on one side of the ICP source 131 ( 141 is electrically connected.

The CCP source 132 and the susceptor 102 are paired to become electrodes for generating CCP in the process chamber 101. That is, a second power supply unit 142 electrically applying high frequency power to the CCP source 132 is electrically connected to one side of the CCP source 132, and the susceptor 102 to one side of the susceptor 102. A third power supply unit 143 for applying power is electrically connected to the inside of the process chamber 101 by a potential difference generated between the CCP source 132 and the susceptor 102 provided in parallel with each other. Plasma is generated.

One side of the process chamber 101 is provided with a source gas supply unit 105 for supplying a source gas for deposition into the process chamber 101. For example, the source gas supply unit 105 may have a nozzle shape connected to the process chamber 101.

However, the shape and number of the source gas supply unit 105 are not limited by the drawings. The source gas supply unit 105 may have various shapes that may supply the source gas into the process chamber 101, and may vary depending on the type of source gas supplied. Other numbers of source gas supplies 105 may be provided. For example, the source gas supply unit 105 may be provided on the susceptor 102 and may have a shower head having a plurality of injection holes. In addition, the source gas supply unit 105 may have a form in which a supply flow path of the source gas passes through the plasma generator 103.

Hereinafter, the plasma generator 103 will be described in detail with reference to FIGS. 2 to 5.

Referring to FIG. 2, the ICP source 131 is coils 311, 312, 313, and 314 wound to form an induction magnetic field in the process chamber 101 when high frequency power is applied. In this case, the coils 311, 312, 313, and 314 may be wound in a planar shape such that the wound surface forms a plane, and may be wound in a quadrangular shape. In addition, the coils 311, 312, 313, 314 are wound such that the wound surface is located on a plane parallel to the surface of the susceptor 102. However, the shapes of the coils 311, 312, 313, and 314 are not limited by the drawings, and the coils 311, 312, 313, and 314 may have various shapes.

Meanwhile, according to the present exemplary embodiment, a plurality of coils 311, 312, 313, and 314 are provided to generate a high-density plasma having a uniform size or more with respect to the large-area substrate 10. For example, the ICP source 131 is composed of four coils (311, 312, 313, 314).

In this case, the four coils 311, 312, 313, and 314 may be formed in the same direction so that the directions of the induction magnetic fields formed in the four coils 311, 312, 313, and 314 are the same. 411 is applied. For example, a high frequency power source 411 is connected to one end of the coils 311, 312, 313, and 314, and a ground 412 is connected to the other end of the coil. Alternatively, the four coils 311, 312, 313, and 314 may be connected to one high frequency power supply in parallel.

Referring to FIG. 4, the ICP source 131 is provided with a first controller 415 for generating a plasma by controlling power applied to the four coils 311, 312, 313, and 314. For example, the first control unit 415 is electrically connected to the four coils 311, 312, 313, and 314, so that the RF power sources having the same frequency to the four coils 311, 312, 313, and 314. It may be a resonance circuit for applying.

In addition, the CCP source 132 is also provided with a second control unit 416 for generating a plasma by controlling the power applied to the CCP source 132.

A matching unit 417 is electrically connected to the first and second controllers 415 and 416 to control the operation of the first and second controllers 415 and 416. RF power of different frequency bands may be applied to the ICP source 131 and the CCP source 132, and the matching unit 417 may be connected to the ICP source through the first and second controllers 415 and 416. RF power of different frequencies may be applied to the 131 and the CCP source 132.

The CCP source 132 has a size and shape corresponding to the susceptor 102 and has a plate shape that forms a plane parallel to the surface of the susceptor 102. Since the CCP source 132 becomes an electrode which generates plasma when a high frequency power is applied, the CCP source 132 is formed of a conductor material.

In particular, according to the present invention, the ICP source 131 and the CCP source 132 simultaneously generate a plasma in the process chamber 101, and the CCP source 132 is provided between the ICP source 131. do. The coils 311, 312, 313, and 314 may be spaced apart from each other by a predetermined interval in order to minimize interference between the induced electric fields generated by the coils 311, 312, 313, and 314. The CCP source 132 ) Is disposed in the space between the spaced coils 311, 312, 313, 314. For example, the CCP source 132 has a mounting portion 321 into which the coils 311, 312, 313, and 314 are inserted and mounted. The mounting part 321 may have a shape in which the coils 311, 312, 313, and 314 corresponding to the coils 311, 312, 313, and 314 may be accommodated in the mounting part 321, and the CCP source 132 may be used. It is formed through).

On the other hand, not only an induction magnetic field by the ICP source 131 but also a storage electric field due to the potential difference between the ICP source 131 and the process chamber 101 is generated, which causes the ICP source 131. Locally capacitively coupled plasma can be generated in the vicinity. The generation of such a local plasma lowers the uniformity of the plasma density generated in the process chamber 101 and causes damage to the inner wall of the process chamber 101.

The CCP source 132 is provided between the ICP source 131 serves as a Faraday shield to prevent the generation of local capacitively coupled plasma around the ICP source 131. That is, the CCP source 132 has an effect of inducing a storage electric field generated by the ICP source 131 above the process chamber 101 to prevent generation of capacitively coupled plasma.

In this case, in order for the CCP source 132 to function as a Faraday shield, the CCP source 132 needs to be formed of a conductive metal material. It is preferable that an opening corresponding to the ICP source 131 is formed in the mounting portion 321 so as to be sufficiently delivered into the process chamber 101. For example, as shown in FIG. 2, the mounting part 321 may have a form in which a lower portion of the coils 311, 312, 313, and 314 is completely opened through the CCP source 132. Alternatively, as shown in FIG. 3, a mounting portion 321 having a rectangular shallow groove shape so that a portion of the surface of the CCP source 132 may be recessed and the coils 311, 312, 313, and 314 may be seated therein. ) Is formed, and a plurality of slits 332 penetrating the CCP source 132 are formed in the mounting portion 321. For example, the slit 332 is formed under the coils 311, 312, 313, and 314 and is discontinuously formed along the winding direction of the coils 311, 312, 313, and 314.

5 schematically illustrates the intensity of the electric field generated at the ICP source 131 and the CCP source 132. Referring to FIG. 5, the x axis represents the length of the ICP source 131 and the CCP source 132, and the y axis represents the strength of the electric field. The induction electric field formed in the ICP source 131 has a substantially parabolic shape in a region corresponding to the coils 311, 312, 313, and 314, and the electric field formed in the CCP source 132 is approximately constant. Appears as a century. The strength of the electric field is locally lowered between the coils 311, 312, 313, and 314 and the coils 311, 312, 313, and 314 due to the shape characteristics of the induction electric field formed in the ICP source 131. There is a problem. In particular, between adjacent coils 311, 312, 313, and 314 and coils 311, 312, 313, and 314, the directions of currents applied to the coils 311, 312, 313, and 314 are formed to be opposite to each other. The attenuation effect of the electric field is shown.

The plasma generating unit 103 reinforces the electric field formed in the CCP source 132 by disposing the CCP source 132 between the coils 311, 312, 313, and 314. In this case, the intensity of the final electric field generated by the plasma generator 103 appears uniformly, and as a result, a plasma having a uniform density is generated.

In addition, the electric field generated in the ICP source 131 and the CCP source 132 is reinforced with each other to generate an electric field having a greater intensity than the electric field generated in a single ICP source 131 or CCP source 132. Therefore, the plasma generating unit 103 can effectively generate a plasma having a uniform density and a high density plasma, and can process the large-area substrate 10.

As described above, the present invention has been described with reference to the preferred embodiments, but those skilled in the art can variously modify the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated that it can be changed.

1 is a longitudinal sectional view for explaining a chemical vapor deposition apparatus according to an embodiment of the present invention;

FIG. 2 is a perspective view of a plasma generator in the chemical vapor deposition apparatus of FIG. 1; FIG.

3 is a modified embodiment of the plasma generation unit of FIG. 2, illustrating a shape of a first electrode;

4 is a block diagram illustrating a controller and a matching unit in the plasma generator of FIG. 2;

FIG. 5 is a graph schematically showing the magnitude of an electric field or a plasma density generated in the plasma generator of FIG. 2.

<Explanation of symbols for the main parts of the drawings>

10: substrate 100: chemical vapor deposition apparatus

101: process chamber 102: susceptor

103: plasma generating unit 104: power supply unit

105: source gas supply unit 131: ICP source

132: CCP source 141: first power supply

142: second power supply unit 143: third power supply unit

311, 312, 313, 314: coils 321, 331: mounting portion

332: slit 411: high frequency power supply

412: ground 415, 416: control unit

417: matching unit

Claims (11)

Process chambers; A susceptor provided in the process chamber to seat a substrate; A plurality of ICP sources provided on the susceptor to generate plasma in an inductively coupled plasma (ICP); And A CCP source provided between the plurality of ICP sources and generating plasma in a conductively coupled plasma (CCP); Chemical vapor deposition apparatus comprising a. The method of claim 1, The ICP source is a chemical vapor deposition apparatus, characterized in that the coil wound in a planar form. The method of claim 2, Chemical vapor deposition apparatus characterized in that the plurality of ICP sources are connected in parallel or in series. The method of claim 1, The CCP source is in the form of a conductive material plate, the chemical vapor deposition apparatus, characterized in that disposed in parallel with the susceptor and the substrate. The method of claim 4, wherein The CCP source is a chemical vapor deposition apparatus, characterized in that the mounting portion is formed is mounted to the ICP source. The method of claim 5, The mounting unit is a chemical vapor deposition apparatus, characterized in that the hole or slit penetrating the CCP source is formed. The method of claim 1, The susceptor is a chemical vapor deposition apparatus, characterized in that connected to the ground. The method of claim 1, A first power supply unit applying high frequency power to the ICP source and a second power supply unit applying high frequency power to the CCP source, Chemical vapor deposition apparatus comprising a matching unit for controlling the operation of the first and second power supply unit. The method of claim 1, Chemical vapor deposition apparatus, characterized in that the dielectric is further provided below the ICP source and the CCP source. Process chambers; A susceptor provided in the process chamber to seat a substrate; A plasma generation unit provided above the susceptor to generate plasma in the process chamber, wherein the plasma generation unit simultaneously generates an electrostatic coupling plasma and an inductive coupling plasma; And A power supply unit applying high frequency power to the plasma generation unit; Including, The plasma generation unit, A CCP source having a flat plate shape parallel to the susceptor and generating plasma in an electrostatic coupling manner; And An ICP source mounted to the CCP source and including a plurality of coils wound in a plane form parallel to the susceptor and generating plasma in an inductive coupling manner; Chemical vapor deposition apparatus comprising a. The method of claim 10, The CCP source has a rectangular plate shape, The coil is wound in a rectangular shape, the chemical vapor deposition apparatus, characterized in that the plurality of coils are spaced apart from each other mounted on the CCP source.

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