KR101430747B1 - Apparatus for Processing Substrate Using Plasma - Google Patents

Abstract

The present invention relates to a Plasma Enhanced Chemical Vapor Deposition (PECVD) apparatus used for processing a substrate such as a solar cell. A PECVD apparatus of the present invention includes a chamber; A suscepter disposed in the chamber and supporting the substrate; A showerhead disposed on the susceptor and supplying a process gas for forming a film to the substrate; A driving unit connected to the susceptor, for raising and lowering the susceptor to adjust a distance between the susceptor and the showerhead; A high frequency power source for applying a high frequency current to the showerhead so that the process gas is excited to generate plasma; And a controller for controlling the driving unit to change the distance between the susceptor and the showerhead continuously or stepwise during a process.

Description

[0001] Apparatus for Processing Substrate Using Plasma [

The present invention relates to a Plasma Enhanced Chemical Vapor Deposition (PECVD) apparatus for depositing a thin film on a substrate using plasma.

Recently, interest in environmental problems and energy depletion has increased, and there is a growing interest in solar cells as energy-efficient alternative energy sources, which are rich in energy resources and have no problems with environmental pollution.

Solar cells can be divided into solar cells, which generate the steam needed to rotate the turbine using solar heat, and solar cells, which convert the photons into electrical energy using the properties of semiconductors. Among them, a photovoltaic cell (hereinafter referred to as "solar cell") that converts light energy into electrical energy by absorbing light to generate electrons and holes generates monocrystalline silicon solar cells, polycrystalline silicon solar cells, thin film solar cells -film solar cells).

 Thin film solar cells are fabricated by depositing p, i, and n films on a glass or plastic transparent substrate. Crystalline solar cells are fabricated by depositing an antireflection film on a silicon substrate. These films are deposited by chemical vapor deposition RTI ID = 0.0 > (PECVD) < / RTI > process.

It is an object of the present invention to provide a substrate processing apparatus using a plasma capable of improving the uniformity of a deposited thin film and cell efficiency.

It is also an object of the present invention to provide a substrate processing apparatus using plasma capable of controlling the deposition rate of the deposited thin film during the process.

The objects of the present invention are not limited thereto, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a substrate processing apparatus using plasma, comprising: a chamber; A suscepter disposed in the chamber and supporting the substrate; A showerhead disposed on the susceptor and supplying a process gas for forming a film to the substrate; A driving unit connected to the susceptor, for raising and lowering the susceptor to adjust a distance between the susceptor and the showerhead; A high frequency power source for applying a high frequency current to the showerhead so that the process gas is excited to generate plasma; And a control unit for controlling the high frequency power source so that the high frequency current applied to the showerhead is increased or decreased during the process.

According to an embodiment of the present invention, the control unit controls the supply amount of the process gas so that the supply amount of the process gas is continuously increased or decreased in the process progress.

According to the embodiment of the present invention, the controller controls the driving unit to change the distance between the susceptor and the showerhead continuously or stepwise during the process.

According to an embodiment of the present invention, there is provided a matching unit for impedance matching between a high-frequency power source and a showerhead in real time when changing the interval between a showerhead and a susceptor, and supplying linearly changing power supplied to the showerhead.

According to an embodiment of the present invention, the matching unit comprises one or more power distribution and impedance matching function between at least one electrode and the high frequency power source.

According to the present invention, the RF power and the process gap between the showerhead (upper electrode) and the substrate can be controlled linearly according to the thin film deposition conditions, thereby enabling low-speed deposition or high-speed deposition during the process.

According to the present invention, low-speed or high-speed deposition can be performed during the process by controlling the supply amount of the process gas according to the thin film deposition conditions.

Further, according to the present invention, it is possible to arbitrarily adjust the film characteristics (a-Si, mc-Si) and the thin film characteristics according to the thickness without stopping the process according to recipe conditions.

In addition, according to the present invention, the height of the susceptor can be controlled during the process so that uniform deposition of the thin film can be achieved by partially adjusting the thin film deposition rate according to the position on the substrate.

The drawings described below are for illustrative purposes only and are not intended to limit the scope of the invention.
1 is a perspective view of a PECVD apparatus for a large area substrate according to an embodiment of the present invention.
2 is a plan view of a PECVD apparatus for a large area substrate according to an embodiment of the present invention.
3 is a side cross-sectional view of a PECVD apparatus for a large area substrate according to an embodiment of the present invention.
4A is a cross-sectional view of the process chamber with the susceptor in a down position.
4B is a cross-sectional view of the process chamber with the susceptor in the up position.
5 is a diagram for explaining a control unit for controlling a high-frequency power source and a landing gear.
6 is a process flow chart of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The above and other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. Each drawing has been partially or exaggerated for clarity. It should be noted that, in adding reference numerals to the constituent elements of the respective drawings, the same constituent elements are shown to have the same reference numerals as possible even if they are displayed on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is a perspective view of a PECVD apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 are a plan view and a side sectional view of a PECVD apparatus according to an embodiment of the present invention.

1 to 3, the PECVD apparatus 1 is for performing a PECVD process on a large area substrate S for a solar cell, and includes a load lock chamber 100, a transport chamber 200, Process module 300.

The load lock chamber 100 is disposed in front of the PECVD apparatus 1. [ The load lock chamber 100 has a structure in which four chambers are stacked, in which two chambers are a loading chamber 110a in which a large-area substrate S is waiting before processing, and the remaining two chambers are processed Can be used as the unloading chamber 110b in which the large-area substrate S is waiting.

Each of the loading chamber 110a and the unloading chamber 110b has a first entrance port 112 and a second entrance port 114 and a stage 120 in which a large area substrate is placed in the interior space. A stage 120 of the loading chamber 110a is provided with a preheating member 130 for preheating a large area substrate and a stage 120 of the unloading chamber 110b is provided with a large area substrate S processed in the process chamber. The cooling member 140 for lowering the temperature of the large-area substrate is provided.

The large-area substrate is carried into the loading chamber 110a by the atmospheric pressure transfer robot (not shown) or is taken out of the unloading chamber 110b. The loading chamber 110a and the unloading chamber 110b constituting the load lock chamber 100 are connected to the transfer chamber 200 at a time when the transfer robot 210 of the transfer chamber 200 loads or unloads the large- ), And when the untreated large-area substrate is supplied from the atmospheric pressure conveying robot or the already-processed large-area substrate is taken out, the atmospheric pressure state is switched to the atmospheric pressure state. That is, the loading / unloading chambers 110a and 110b of the load lock chamber 100 maintain the pressure while crossing the vacuum state and the atmospheric pressure state, respectively, in order to prevent the atmospheric pressure state of the transfer chamber 200 from being changed And is divided into a plurality of loading chambers 110a and unloading chambers 110b for processing such pressure fluctuations as quickly as possible. Of course, the chambers of the load lock chamber can be used for both loading and unloading as well as for loading and unloading.

The transfer chamber 200 is located at the center of the load lock chamber 100 and the process module 300. The transfer chamber 200 is connected to the load lock chamber 100 and the process chambers 300a of the process module 300 and has a transfer robot 210 for transferring a large area substrate. The transfer robot 210 is a robot having one or two arm structures capable of taking out the large area substrate placed on the stage 120 of the loading chamber 110a and transferring the large area substrate into the process chamber 300a of the process module 300. [ .

In addition to the structure shown in the present embodiment, the transport robot 210 provided in the transport chamber 200 may use various robots used in a conventional solar cell manufacturing process and a flat panel display panel manufacturing process. For example, a robot having an arm of a double blade structure capable of handling two large-area substrates S as one arm, a robot having one or more arms, or a robot employing them in combination may be used have.

The process modules 300 are connected to a side surface of the transfer chamber 200. In this embodiment, three process modules 300 are arranged at intervals of 90 degrees around the transfer chamber 200. However, if necessary, four to five process modules 300 may be arranged have.

The process module 300 performs a plasma chemical vapor deposition (PECVD) process for depositing a thin film on a substrate using plasma. The substrate used in the thin film deposition process may be, for example, a transparent substrate made of glass or plastic used for manufacturing a thin film solar cell, or a silicon substrate used for manufacturing a crystal solar cell (solar cell) . The process module 30 can deposit a p-layer, an i-layer and an n-layer on a transparent substrate of a thin-film solar cell or an anti-reflection layer on a silicon substrate of a crystalline solar cell. In addition, the process module 30 may deposit a thin film on a glass substrate used for manufacturing a flat panel display device.

Each of the process chambers 300a is a vacuum chamber, and in this embodiment, the process module 300 is divided into four process chambers 300a, Although the process chambers 300a are constructed in a stacked structure, four or more process chambers may be stacked if the height is allowed.

Below the process chamber 300a positioned at the lowermost stage, an elevating device 400 having an elevation driving part 410 is installed. The elevating device 400 includes a susceptor 310 installed in each of the four process chambers 300a, Respectively. The elevating driving force of the elevating apparatus 400 can be transmitted to the susceptors of the respective processing chambers 300a through the elevating shafts 360. The process module 300 having such a structure can reduce the height of the equipment as much as possible, so that more process chambers 300a can be stacked.

As described above, the PECVD apparatus 1 of the present invention can increase the process and production flexibility and maximize the productivity per apparatus by allowing a plurality of (more than 12) process chambers 300a to be arranged in the same area. In particular, the present invention is well suited for a tandem solar cell fabrication process in which the thickness of a deposited layer is as thick as ~ 20,000 angstroms (2 um), and thus deposits a microcrystalline silicon thin film that takes longer than other thin films.

4A is a cross-sectional view of the process chamber with the susceptor in the down position, and Fig. 4B is a cross-sectional view of the process chamber with the susceptor in the up position. And Fig. 5 is a diagram for explaining a control unit for controlling the high-frequency power source and the landing gear.

4A to 5, the process chamber 300a is shielded from the outside, and provides a plasma forming region (reaction space) between the susceptor 310 and the showerhead 320. As shown in FIG.

A side wall of the process chamber 300a is provided with a slot valve 380 for determining whether the transfer chamber 200 is in communication with the reaction space. S) is loaded (or when the large area substrate is taken out), the slot valve 380 is opened.

The process chamber 310 is provided with lift pins 390 which support the large area substrate S when the substrate is carried in or out and the substrate support is supported by the susceptor 310 As shown in FIG. That is, when the large area substrate is loaded by the carrying robot 210, the substrate is supported on the lift pins 390 in a state in which the susceptor 310 is lowered. As the susceptor 310 is moved up and down, And the lift pins 390 are inserted into a pinhole formed in the susceptor 310. The susceptor 310 is mounted on the susceptor 310,

In the upper space of the susceptor 310, an electrode type shower head 320 connected to a high frequency power source 500 (shown in FIG. 5) as a plasma source for applying a high frequency current to form plasma is provided. A matching unit 510 is provided between the high frequency power source 500 and the shower head 320. The shower head 320 is formed with small-diameter spray holes (not shown), and the surface is polarized to prevent arc generation due to plasma. In addition, the shower head 320 is connected to a gas supply unit 600 (shown in Fig. 5) for supplying a process gas. The gas supply unit 600 is controlled by the control unit 700, and the supply amount of the process gas by the control unit 700 can be changed stepwise or continuously.

The showerhead 320 is supplied with a plasma-forming mixed gas for thin film deposition on a substrate according to the type of processing performed in the process chamber 300 through the gas supply unit 600. The plasma-forming mixed gas supplied from the gas supply unit 600 is plasma-plasmaized in the shower head 320 to deposit a predetermined thin film on the large-area substrate S and then exhausted through the gas exhaust pipe 370.

The susceptor 310 is installed so as to be movable up and down in the process chamber 300a, and is electrically grounded. The large-area substrate S is seated on the susceptor 310. A heater (not shown) for heating the large area substrate S is mounted inside the susceptor 310. The susceptor 310 has its bottom surface supported by the susceptor supports 350. The susceptor supporter 350 is longer than the susceptor 310, and the elevating shaft 360 is vertically installed at both ends.

The lifting shaft 360 is connected to another lifting shaft 360 of the process chamber 300a having an upper portion passing through the shower head 320. [ That is, the lift shaft 360 serves to transmit the lift force of the lift apparatus 400 to each other. The lifting shaft 360 located at the lowermost end is connected to the lifting device 400. The elevating and lowering driving force of the elevating apparatus 400 is transferred to the respective processing chambers 300a through the lifting shafts 360 and simultaneously elevates and elevates the susceptors 310 installed in the respective processing chambers 300a.

5, the controller 700 may control the elevating apparatus 400 to continuously or stepwise change the distance between the susceptor 310 and the shower head 320 during the process, The high frequency power supply 500 can be controlled so that the applied high frequency power is continuously changed (stepped up or decreased) without interruption of the power supply.

The control unit 700 controls the gas supply unit 600 to increase or decrease the supply amount of the process gas supplied from the gas supply unit 600 to the shower head 320 either stepwise or continuously, Deposition was possible.

6 shows a process flow chart in the present invention.

6, when the process setting S12 is completed at the start of the process (S10), the high frequency power (hereinafter referred to as a supply power) to be supplied to the showerhead and the interval between the showerhead 320 and the susceptor 310 Hereinafter referred to as an electrode interval) is first set (S14), and the supply power is supplied through a matching process (S16, S18). If the supply power, the electrode interval, and the process gas supply amount are required to be changed (S20), the supply power, the electrode interval, and the process gas supply amount are reset (S22) do.

As described above, since the supply power, the electrode interval, and the process gas supply amount are adjusted without interruption of the power supply during the process, the film deposition can be continuously performed without interruption, thereby improving the film characteristics with different conditions.

For example, if the electrode interval is narrowed, the film deposition is good at the center portion of the substrate, and conversely, if the electrode interval is widened, the film deposition at the edge portion of the substrate is good. By using this point, it is possible to intensively deposit a region where the film deposition rate is relatively low during the process. When the supply power is lowered, the deposition rate is lowered while the hardness of the deposition layer is improved. When the supply power is increased, the deposition rate is improved while the hardness of the deposition layer is lowered. The process can be progressed while gradually increasing the supply power, and vice versa. Further, the supply power, the electrode spacing, and the supply amount adjustment of the process gas can be performed independently of each other or in conjunction with each other.

As described above, according to the thin film deposition conditions, the supply power, the electrode spacing, and the process gas supply amount are linearly controlled to enable low-speed or high-speed deposition during the process. In addition, it is possible to arbitrarily adjust the film characteristics (a-Si, mc-Si) and the thin film characteristics depending on the thickness without stopping the process according to the recipe conditions.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Description of the Related Art
100: load lock chamber
200: conveying chamber
300: Process module
300a: process chamber
310: susceptor
320: Shower head

Claims (5)

A substrate processing apparatus using plasma, comprising:
chamber;
A suscepter disposed in the chamber and supporting the substrate;
A showerhead disposed on the susceptor and supplying a process gas for forming a film to the substrate;
A driving unit connected to the susceptor, for raising and lowering the susceptor to adjust a distance between the susceptor and the showerhead;
A high frequency power source for applying a high frequency current to the showerhead so that the process gas is excited to generate plasma; And
And a control unit for controlling the high frequency power source so that the high frequency current applied to the showerhead is increased or decreased during the process.
Wherein the control unit controls the driving unit to change the distance between the susceptor and the showerhead continuously or stepwise during the process. delete The method according to claim 1,
Wherein the control unit controls the supply amount of the process gas so that the supply amount of the process gas is continuously or stepwise increased or decreased during the process. A substrate processing apparatus using plasma, comprising:
chamber;
A suscepter disposed in the chamber and supporting the substrate;
A showerhead disposed on the susceptor and supplying a process gas for forming a film to the substrate;
A driving unit connected to the susceptor, for raising and lowering the susceptor to adjust a distance between the susceptor and the showerhead;
A high frequency power source for applying a high frequency current to the showerhead so that the process gas is excited to generate plasma;
A control unit for controlling the high frequency power source so that a high frequency current applied to the showerhead is increased or decreased during a process; And
And a matching unit for impedance matching between the high frequency power source and the showerhead in real time when the distance between the showerhead and the susceptor is changed in accordance with a linear change supply of electric power to be supplied to the showerhead. Device. 5. The method of claim 4,
Wherein the matching unit comprises one or more power distribution and impedance matching function between at least one electrode and a high frequency power source.

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