KR20100092111A - Apparatus for fabricating solar cell and method for fabricating solar cell uesing the same - Google Patents

Abstract

PURPOSE: The manufacturing method of the manufacturing device of the solar battery and solar battery using the same forms the thin film patterns of the solar battery on the predetermined position. CONSTITUTION: The camera(110) in advance takes a photograph of the location examining laser. The laser-irradiated region(120) examines laser in the thin film material. The error determining unit(130) decides error between the search point of the laser which in advance in advance records with the fixed the laser irradiation route and camera. It controls the laser-irradiated region and the controller(140) revises error.

Description

Apparatus For Fabricating Solar Cell And Method For Fabricating Solar Cell Uesing the same}

The present invention relates to a solar cell, and more particularly, to a manufacturing apparatus of a solar cell capable of preventing defects in the manufacturing process of the solar cell and a method of manufacturing a solar cell using the same.

In general, a solar cell is a semiconductor device that converts solar energy into electrical energy, and has a junction type of a p-type semiconductor and an n-type semiconductor. The basic structure is the same as that of a diode. Most ordinary solar cells consist of large area pn junction diodes, and the basic requirement for solar cells for photovoltaic energy conversion is that the electrons are asymmetric in the semiconductor structure. It should be. In other words, the n-type semiconductor region has a large electron density and a small hole density, and the p-type semiconductor region is formed in the opposite direction. Therefore, in the thermal equilibrium, a diode composed of a junction of a p-type semiconductor and an n-type semiconductor has an imbalance of electric charge due to diffusion due to a concentration gradient of carriers, and thus an electric field is formed so that a carrier no longer exists. Does not occur. In this case, when light is applied to the pn junction diode above the band gap energy, which is the energy difference between the conduction band and the valence band of the material, the electrons subjected to the light energy are transferred from the valence band to the conduction band. Here it is. At this time, the electrons excited by the conduction band can move freely, and holes are generated in the valence band where electrons escape. This is called an excess carrier, and the excess carriers diffuse by concentration differences in the conduction band or the valence band. At this time, electrons excited in the p-type semiconductor and holes made in the n-type semiconductor are called respective minority carriers, and carriers in the p-type or n-type semiconductor (ie, p-type holes and n-type semiconductors) before conventional bonding are formed. The former is called a majority carrier. At this time, the majority carriers are disturbed by the flow due to the energy barrier due to the electric field, but electrons, which are p-type minority carriers, can move toward the n-type. The diffusion of the minority carrier causes a potential drop in the pn junction diode, and when the electromotive force generated at the anode terminal of the pn junction diode is connected to an external circuit, it acts as a solar cell.

On the other hand, solar cells using silicon are largely divided into single crystal and polycrystalline materials and are basically used in solar cells as pn homojunctions. Single crystal is a high quality material with high purity and low crystal defect density, which can achieve high efficiency, but is expensive, and polycrystalline material can manufacture a battery having an efficiency that can be commercialized at a relatively low cost.

Such a solar cell is composed of a first electrode (or "anode electrode"), a semiconductor pattern and a second electrode (or "cathode electrode") sequentially formed on a substrate, and supplies a required amount of electricity. In order to have a plurality of sub solar cells are connected in series. In addition, the first electrode, the semiconductor pattern, and the second electrodes of the conventional solar cell are formed using a laser rather than a photolithography process. For example, the first electrode is formed by depositing a transparent electrode material on a substrate and irradiating a laser beam to a region to be removed to remove a specific portion. However, in the irradiation method using the laser beam, a defect occurs in the manufacturing process of the solar cell as the position of the substrate is somewhat disturbed or an abnormal thin film pattern is formed in the laser irradiation process.

The present invention is to solve the above problems, in particular, to provide a solar cell manufacturing apparatus and a method for manufacturing a solar cell using the same to form a thin film pattern of the solar cell in place to prevent defects in the manufacturing process. There is.

An apparatus for manufacturing a solar cell according to an embodiment of the present invention for achieving the above object includes a deposition apparatus for depositing a thin film material; A laser device for irradiating a laser onto the thin film material, the laser device comprising: a camera for photographing a position to be irradiated with a laser in advance; A laser irradiator for irradiating a laser onto the thin film material; An error determination unit that determines an error between a laser irradiation path preset in advance by using the position information of the point photographed by the camera and an irradiation point of the laser photographed by the camera before laser irradiation; And controlling the laser irradiation unit to correct the error and irradiate the laser according to the corrected result.

The camera is installed in the front of the laser device in the advancing direction of the laser irradiation unit, characterized in that the laser irradiation unit is installed behind the laser device.

A method of manufacturing a solar cell according to the present invention includes a first step of forming first holes in a line shape positioned at predetermined intervals on a substrate and forming first electrodes electrically separated by the first holes; A second step of exposing the first electrode and spaced apart from each other and forming second holes parallel to the first holes, and forming semiconductor patterns electrically separated by the second holes; And forming a third hole exposing the semiconductor pattern and spaced apart from each other, the third holes being parallel to the second hole, and forming a second electrode electrically separated by the third holes. The first to third steps include depositing a thin film material; Photographing the irradiation path of the laser in advance using a camera before the laser is irradiated; Determining an error between a preset laser irradiation path and an irradiation path of a laser photographed by the camera before laser irradiation; And correcting the error so that the laser is irradiated with the preset laser irradiation path.

The step of photographing the irradiation path of the laser in advance, the step of determining the error before the laser irradiation and the step of correcting the error is characterized in that it is repeated until the laser irradiation process is finished.

The first to third holes may be formed by irradiating the laser on the thin film material.

An apparatus for manufacturing a solar cell and a method for manufacturing a solar cell using the same according to an exemplary embodiment of the present invention photograph an area to be irradiated before the laser is irradiated and correct an error generated when the actual laser is irradiated using the photographing result. As a result, the laser can be accurately irradiated to the laser irradiation path preset by the user. As a result, the thin films constituting the solar cell can be accurately formed in position, thereby preventing defects in the manufacturing process.

Hereinafter, a solar cell manufacturing apparatus and a manufacturing method of a solar cell using the same according to an embodiment of the present invention having the above characteristics will be described in more detail with reference to the accompanying drawings.

First, FIG. 1 is sectional drawing which shows the solar cell in this invention.

Referring to FIG. 1, a solar cell has a structure in which a sub solar cell P including a first electrode 10, a semiconductor pattern 20, and a second electrode 30 sequentially stacked on a substrate 200 is connected in series. Has In the series connection method, the second electrode 30 of the first sub solar cell P1 is connected to the first electrode 10 of the second sub solar cell P2 and the second of the second sub solar cell P2 is connected. The electrode 30 is connected to the first electrode 10 of the third sub solar cell P3 so that the first to third sub solar cells P1, P2, and P3 are connected in series. The first electrodes 10 are electrically separated by the first hole 12 formed in a line shape, and the semiconductor patterns 20 are electrically separated by the second hole 22 formed in a line shape, and the third electrode The 30 are electrically separated by the third hole 32 formed in the form of a line. The first to third holes 12, 22, and 32 are formed to be parallel to each other.

The solar cell manufacturing apparatus according to the present invention includes a deposition apparatus for depositing a thin film material on the substrate 200, and a laser apparatus for patterning the thin film material deposited on the substrate 200 using a laser.

Various vapor deposition apparatuses may be used as the vapor deposition apparatus according to a material to be deposited, such as a chemical vapor deposition apparatus and a sputtering apparatus.

The laser device is shown in FIG. 2 as a device capable of forming a thin film pattern having a desired shape by irradiating a laser to the thin film material.

2 shows that the laser device 100 irradiates the laser 22 to the back surface 200a of the substrate 200 and the laser is irradiated onto the thin film material 10a via the substrate 200.

Referring to FIG. 2, the laser device 100 includes a CCD camera 110, a laser irradiator 120 to which the laser 122 is irradiated, an error determiner 130, and a controller 140.

The CCD camera 110 is located in front of the advancing direction of the laser device to photograph the laser irradiation path to be irradiated with the laser in advance. In addition, the CCD camera 110 supplies position information of the photographed irradiation path to the error determining unit 130. Here, the positional information indicates coordinates in the X direction (horizontal direction) and coordinates in the Y direction (vertical direction), for example.

The error determining unit 130 stores position information on a preset laser irradiation path. Accordingly, the error determination unit 130 uses the position information of the preset laser irradiation path and the position information of the point photographed by the CCD camera 110 to set the laser irradiation path and the laser to be irradiated from the laser irradiation unit 120. Pre-determine the error between survey points.

The controller 140 controls the driving and the position of the laser irradiation unit 120. In addition, the control unit 140 irradiates the laser 22 by correcting the irradiation path of the laser emitted from the laser irradiation unit 120 using the error determined by the error determining unit 130.

The laser irradiator 120 is positioned behind the traveling direction of the laser device and irradiates the laser 22 to the thin film 10a formed on the substrate 200 as shown in FIG. 1 under the control of the controller 140. Here, the region to which the laser 122 is irradiated is the region where the first to third holes 12, 22, and 32 are to be formed in FIG. 1.

Hereinafter, a method of manufacturing a solar cell using the laser device shown in FIG. 2 will be described with reference to the flowchart shown in FIG. 3 and FIGS. 4A to 4C.

First, transparent conductive oxide (TCO) is deposited on the substrate 200 using a deposition method such as sputtering.

Thereafter, before starting the laser irradiation, the CCD camera 110 first checks the start coordinates of the preset laser irradiation path (S10). The point photographed by the CCD camera 110 is a starting point of the preset laser irradiation path. If it is determined that the laser 22 is irradiated from the laser irradiator 120, the laser irradiation process is performed (S12). The area to be irradiated with the laser 22 during the laser process is previously performed by the CCD camera 110. Continuously photographed (S14) and the photographed position information or coordinate information is immediately supplied to the error determining unit 130 (S16).

The error judging unit 130 uses the predetermined position information of the laser irradiation path and the position information of the point photographed by the CCD camera 110 to set the laser irradiation path and the irradiation point of the laser to be irradiated from the laser irradiation unit 120. (S18) And the controller 140 corrects the irradiation point of the laser emitted from the laser irradiation unit 120 to irradiate the laser by using the error determined by the error determination unit 130. After S20, as the steps S14 and S20 are repeatedly performed, the laser 122 can be accurately irradiated to the laser irradiation path preset to form the hole. Accordingly, as shown in FIG. 4A, the laser 122 is irradiated in the rear direction of the substrate 200. Here, the laser irradiation path to which the laser 122 is irradiated is an area where the first holes 12 are to be formed. Thereafter, when the laser irradiation process is completed, as shown in FIG. 4B, the first hole 12 and the first electrode 10 having a line shape exposing the substrate 200 may be normally formed on the substrate 200. do.

The P-type semiconductor, the intrinsic semiconductor, and the n-type semiconductor are sequentially stacked on the substrate 200 on which the first electrode 10 is formed.

Subsequently, as the processes of steps S10 to S20 are repeated, a second hole 22 and a semiconductor pattern 20 having a line shape exposing the first electrode 10 are formed as shown in FIG. 4C.

As a metal material such as aluminum (Al) or aluminum neodium (AlNd) is deposited on the substrate 200 on which the semiconductor pattern 20 is formed, the process of steps S10 to S20 is repeated, as shown in FIG. 1. Similarly, the third hole 32 and the second electrode 30 in the form of a line exposing the semiconductor pattern 20 are formed. Here, the second electrode 20 of the front sub solar cell P is in contact with the first electrode 10 of the next sub solar cell P through the second hole 22.

Accordingly, unlike the related art, the laser is normally irradiated onto a desired area so that the thin film patterns constituting the solar cell can be normally formed. This effect will be described in more detail with reference to FIGS. 5 to 7 as follows.

When the thin film is patterned using a laser, the position of the substrate 200 may be slightly disturbed, or the laser may be irradiated to a region outside the preset laser irradiation path due to an error in the laser irradiation process. For example, when a laser irradiation process is normally performed, thin film patterns are formed to have a shape as illustrated in FIG. 5. Here, FIG. 5 is a plane photograph which shows area | region A in FIG. Pattern1 in FIG. 5 is an area corresponding to the first hole 12 in FIG. 1, and Pattern2 in FIG. 5 is an area corresponding to the second hole 22 in FIG. 1. That is, as shown in FIG. 1, the second electrode 30 of the front sub solar cell P passes through the semiconductor pattern 20 to expose the first electrode 10 of the next sub solar cell P. It is to be connected to the first electrode 10 of the next sub solar cell P through 22. However, when the laser irradiation process is not normally performed, as shown in FIG. 6, as the laser irradiation process proceeds, the distance between the Pattern 1 and the Pattern 2 is not kept constant but becomes narrow. That is, the gap between the pattern 1 and the pattern 2 at the upper end of the line-shaped region irradiated with the laser is 80 μm, but gradually decreases to 50 μm and 30 μm, and the lower end of the line-type region is 0 μm. As a result, the second electrode 30 of the front sub solar cell P is not connected to the first electrode 10 of the next sub solar cell P or the second electrode of the front sub solar cell P ( A problem may occur in which 30) is connected to the first electrode 10 of the front sub solar cell P instead of the next stage. However, when the laser is irradiated using the laser device of the present invention, before the laser irradiation proceeds, the irradiation point of the laser is photographed by the CCD camera 110 in advance, and the error from the irradiation point previously designated by the error determining unit 130 is determined. By judging and correcting this, the laser can be accurately irradiated to the preset irradiation path.

FIG. 7 is a diagram illustrating a result of simulating the formation of thin film patterns at three arbitrary points when a solar cell is formed using the laser device described above. Referring to FIG. 6, it can be seen that the widths of the patterns at the three points do not have errors as large as 47 μm, 50 μm, and 53 μm.

As described above, in the apparatus for manufacturing a solar cell according to the present invention and a method for manufacturing the solar cell using the same, a user presets the area to be irradiated before the laser is irradiated and the laser is irradiated using the photographing result. The laser irradiation path can be accurately irradiated with the laser, as a result, the first electrode 10, the second electrode 30 and the semiconductor pattern 20 constituting the solar cell can be formed accurately in place. Therefore, the defect in the manufacturing process can be prevented.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of.

1 is a cross-sectional view showing a solar cell in the present invention.

2 is a view showing an apparatus for manufacturing a solar cell according to the present invention.

3 is a flowchart illustrating a method of manufacturing a solar cell using the apparatus for manufacturing a solar cell shown in FIG. 2.

Figures 4a to 4c is a process chart showing a method of manufacturing a solar cell using the apparatus for manufacturing a solar cell shown in FIG.

Fig. 5 is a simulation diagram showing the shape of a thin film pattern when the laser irradiation step is normally performed.

Fig. 6 is a simulation diagram showing the shape of a thin film pattern when the laser irradiation step is abnormally performed.

7 is a simulation diagram showing the formation of a thin film pattern when the solar cell is formed using the solar cell manufacturing apparatus according to the present invention.

* Brief description of symbols for the main parts of the drawings.

100: laser device 110: CCD camera

120: laser irradiation unit 130: error determination unit

200 substrate 10 first electrode

12: first hole 20: semiconductor pattern

22: second hole 30: second electrode

32: third hole

Claims (5)

A deposition apparatus for depositing a thin film material; A laser device for irradiating a laser to the thin film material, The laser device A camera which photographs a position to be irradiated with a laser in advance; A laser irradiator for irradiating a laser onto the thin film material; An error determination unit that determines an error between a laser irradiation path preset in advance by using the position information of the point photographed by the camera and an irradiation point of the laser photographed by the camera before laser irradiation; And a control unit which controls the laser irradiation unit to correct the error and irradiates a laser according to the corrected result. The method of claim 1, The camera is installed in front of the laser device in the direction of the laser irradiation unit and the laser irradiation unit is a solar cell manufacturing apparatus, characterized in that installed on the back of the laser device. Forming a first hole in a line shape spaced apart from the substrate and forming first electrodes electrically separated by the first holes; A second step of exposing the first electrode and spaced apart from each other and forming second holes parallel to the first holes, and forming semiconductor patterns electrically separated by the second holes; And forming a third hole exposing the semiconductor pattern and spaced apart from each other, and forming third holes parallel to the second hole, and forming a second electrode electrically separated by the third holes. The first to third steps Depositing a thin film material; Photographing the irradiation path of the laser in advance using a camera before the laser is irradiated; Determining an error between a preset laser irradiation path and an irradiation path of a laser photographed by the camera before laser irradiation; And correcting the error so that the laser is irradiated with the predetermined laser irradiation path. The method of claim 3, wherein Photographing the irradiation path of the laser in advance, determining the error before laser irradiation, and correcting the error are repeated until the laser irradiation process is completed. . The method of claim 3, wherein And the first to third holes are formed by irradiating the thin film with the laser.

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