TWI495136B - Solar cell and method of manufacturing same - Google Patents

Description

Solar cell and method of manufacturing same

The present invention relates to a solar cell and a method of manufacturing the same.

A solar cell is a device that converts light energy into electrical energy using semiconductor characteristics.

The solar cell has a PN junction structure in which a positive (P) type semiconductor is bonded to a negative (N) type semiconductor. When sunlight is incident on a solar cell having such a structure, the energy retained by the incident solar rays generates holes and electrons in the semiconductor. At this time, the electric field generated in the PN junction causes the hole (+) to p. The direction of the semiconductor shifts, causing the electrons (-) to move toward the N-type semiconductor, thereby generating potential charging, thereby inducing a current.

Such a solar electric field is classified into a substrate type solar cell and a thin film type solar cell.

The substrate type solar cell is a solar cell manufactured by using a material such as ruthenium for a substrate, and the thin film type solar cell is a solar cell manufactured by forming a semiconductor in the form of a film for a substrate using a material such as glass.

The substrate type solar cell exhibits slightly superior efficiency as compared with the thin film type solar cell, but has disadvantages in that thickness is minimized in terms of handling, and manufacturing cost is increased due to the use of an expensive semiconductor substrate.

Thin film type solar cells exhibit a slightly lower efficiency than substrate type solar cells, but can be manufactured to a small thickness, use inexpensive materials, thereby reducing manufacturing costs, and being suitable for mass production.

The thin film type solar cell is manufactured by forming a front electrode on a substrate such as glass, forming a semiconductor layer on the front electrode, and forming a back electrode on the semiconductor layer. Since the front electrode forms a light receiving face on which light is incident, a transparent conductive material such as zinc oxide (ZnO) is used for the front electrode. Due to the resistance of the transparent conductive material, as the size of the substrate increases, the disadvantage is that the power loss also increases.

Therefore, a thin film type solar cell is generally designed as a structure in which a plurality of unit cells are connected in series to minimize power loss caused by resistance of a transparent conductive material.

"1a", "1b", "1c", "1d", "1e", and "1f" are structures with a plurality of unit cell strings connected. A cross-sectional view of a method of manufacturing a conventional thin film solar cell.

Referring to "FIG. 1a", the front electrode 20 is formed on the substrate 10.

Referring to FIG. 1b, in order to divide the front electrode 20 into a plurality of unit front electrodes, a predetermined region of the front electrode 20 is removed by a laser scribing process (P1) to form a first trench (t1).

Referring to "FIG. 1c", the semiconductor layer 30 is formed over the entire surface of the substrate 10 including the front electrode 20.

Referring to FIG. 1d, in order to divide the semiconductor layer 30 into a plurality of unit semiconductor layers, a predetermined region of the semiconductor layer 30 is removed by a laser scribing process (P2) to form a second trench (t2).

Referring to "FIG. 1e", the back electrode 50 is formed on the semiconductor layer 30.

Referring to FIG. 1f, a predetermined region of the back electrode 50 and the semiconductor layer 30 is removed by a laser scribing process (P1) to form a third trench (t3). Therefore, a thin film type solar cell having a structure in which a plurality of unit cells are connected in series can be obtained.

Such a thin film type solar cell is classified into a superstrate-type solar cell and a substrate type solar cell, in which sunlight in a surface type solar cell is directly incident on a transparent substrate such as glass, in a substrate type solar cell Using a flexible substrate of low transparency, sunlight is incident through the transparent conductive layer laminated on the substrate.

The "Fig. 2" is a schematic diagram of a laser scribing method for a conventional solar panel. The "Fig. 3" is a schematic diagram of a laser scribing method for a conventional substrate type solar cell.

Please refer to "Fig. 2" because the surface type solar cell uses a transparent glass through which the laser can pass, and the laser passes through the substrate 60 and the transparent conductive layer 61 appearing under the substrate 60 can be removed. As shown, the particles of the removed transparent conductive layer 61 are dispersed under the substrate 60 and do not remain on the transparent conductive layer 61.

In the meantime, please refer to "Fig. 3". The substrate type solar cell uses the flexible substrate 70 having a low light transmittance. Since the laser cannot pass through the substrate 70, the treatment of the film surface is required.

The back electrode 71 and the anti-diffusion layer 72 are laminated in a state above the substrate 70 in this order, and the laser is irradiated to remove the back electrode 71 and the anti-diffusion layer 72. For this reason, particles generated during laser scoring appear as residuals on the anti-diffusion layer 72 or are melted and removed by the high energy of the laser to be laminated on the edge of the anti-diffusion layer 72 to form a burr ( Burr)73.

The "Fig. 4" is a schematic view showing the burrs generated by laser scribing in a conventional substrate type solar cell. The "figure 5" is a schematic diagram showing the problem caused by the burrs occurring in the conventional substrate type solar cell.

Referring to "Fig. 4", particles generated by P1 laser scribing in a substrate type solar cell are laminated on the edge of the diffusion resistant layer 72 to form a burr 73. The burrs 73 have a height of several hundred nanometers (nm).

Referring to FIG. 5, the back electrode 71 and the anti-diffusion layer 72 laminated on the substrate 70 are subjected to P1 laser scribing to generate a burr 73.

The burr 73 generated during the P1 laser scribing passes through the semiconductor layer 74 formed by the subsequent process on the anti-diffusion layer 72, and contacts the front electrode 75. The burr 73 contacts the front electrode 75, causing the front electrode 75 to contact the back electrode 71, thereby interfering with the insulation of the solar cell and causing deterioration of the efficiency of the solar cell. In severe cases, the burr 73 has the drawback of hindering the normal operation of the solar cell.

Accordingly, the present invention provides a solar cell and method of fabricating the same that substantially obviate one or more of the problems caused by the limitations and disadvantages of the prior art.

It is an object of the present invention to provide a solar cell and a method of manufacturing the same that avoids degradation of insulation and efficiency caused by burrs generated during laser scribing.

The present invention provides a method for fabricating a solar cell comprising: forming a back electrode on a substrate; forming an anti-diffusion layer on the back electrode in order to obtain the object and other features of the present invention. The first laser scribe is performed to divide the back electrode into a plurality of unit back electrodes; the second laser scribe is performed along one side of the first line formed by the first laser scribe, so that the second laser scribe is processed The area overlaps the first line to remove the burrs generated by the first laser scoring; and three laser scribings are performed along the other side of the first line such that the processing area of the three laser scoring overlaps the first line to clear Burst.

The second laser scribe is completed simultaneously or sequentially with three laser scribes.

It is assumed that the line formed by the second laser scribe is defined as the second line, and the line formed by the three-shot laser scribe is defined as the third line, and the width of the second line and the third line is 1/ of the width of the first line. 2 or less.

The width of the second and third lines may overlap the width of the first line by about 10 micrometers (μm) or more.

The first line has a width of from about 50 to about 60 microns and the second line and the third line have a width of from about 20 to about 30 microns.

Compared to the first laser scoring, the second laser scoring and the three laser scoring are performed in accordance with low frequency and low power.

The substrate is a flexible substrate selected from aluminum foil, SUS foil, and translucent film.

The back electrode is selected from the group consisting of silver, aluminum, silver + aluminum, silver + magnesium, silver + manganese, silver + germanium, silver + zinc, silver + molybdenum, silver + nickel, silver + copper, and silver + aluminum + zinc. .

The anti-diffusion layer contains any one of zinc oxide, boron-doped zinc oxide (ZnO: B), aluminum-doped zinc oxide (ZnO: Al), germanium (Ge), aluminum oxide (Al 2 O 3 ) or germanium dioxide (SiO 2 ).

According to another aspect, a method for fabricating a solar cell according to the present invention includes: forming a back electrode on a substrate; completing a first laser scribe to divide the back electrode into a plurality of unit back electrodes; forming along the first laser scribe One side of the first line completes the second laser scribe, such that the treated area of the second laser scribe is overlapped with the first line to remove the burrs generated by the first laser scribe; and the other along the first line Three laser scribes are completed on the side, so that the processing area of the three laser scribes overlaps with the first line to remove the burrs.

According to another aspect, a method for fabricating a solar cell according to the present invention includes: forming a back electrode on a substrate; forming an anti-diffusion layer on the back electrode; completing a first laser scribe to divide the back electrode into a plurality of unit back electrodes; And performing secondary laser scribing on both sides of the first line formed along the first laser scoring, such that the processing area of the second laser scoring overlaps with the first line to remove the burrs generated by the first laser scribing .

The area of the area where the second laser marking is completed is larger than the area of the area where the first laser marking is completed.

According to still another aspect, a solar cell according to the present invention includes: a substrate; a back electrode and an anti-diffusion layer are separated by a first trench on the substrate; and a semiconductor layer is transmitted through the second trench on the anti-diffusion layer ( T2) is spaced; and the front electrode is spaced through the third trench on the semiconductor layer, wherein the edge of the anti-diffusion layer adjacent to the first trench comprises a step lower than the top of the anti-diffusion layer.

The width of the step is 1/4 or less of the width of the first groove.

It is to be understood that the foregoing general description of the invention and the claims

The configuration and function of the preferred embodiment of the present invention will be described in conjunction with the drawings. When the elements are denoted by reference numerals in the drawings, it should be noted that although the same elements are present in different drawings, the same elements are denoted by the same or similar reference numerals.

"6a", "6b", "6c", "6d", "6e", "6f", "6g", "6h", " 6i" and "6j" are schematic views showing a manufacturing process of a solar cell according to an embodiment of the present invention.

The flexible solar cell is formed by laminating an electrode layer and a semiconductor layer on a flexible substrate having low light transmittance, and the flexible substrate is light, foldable, and portable, whereby the flexible solar cell can be equipped with a sunroof and a sunshade. Board (sun visor), blinds, etc. In a flexible solar cell, sunlight is not incident on the flexible substrate, but is incident on the transparent conductive layer laminated on the flexible substrate. This type of solar cell is also called a germanium substrate type solar cell.

The use of laser patterned processes is a very important factor in the manufacture of flexible solar cells. The flexible solar cell uses a flexible substrate having a low light transmittance because the laser cannot pass through the flexible substrate, thereby requiring film surface treatment. Particles generated during laser scoring may appear as residues or may be laminated to the edges of the electrode layer that is melted or removed by the high energy of the laser, producing burrs. The burrs hinder the insulation of the solar cells, thereby causing deterioration of the efficiency of the solar cells and hindering the normal operation of the solar cells. Accordingly, the present invention provides a method of manufacturing a solar cell to effectively remove burrs.

Referring to "FIG. 6a", the back electrode 121 and the anti-diffusion layer 122 are formed on the flexible substrate 110 (or substrate). The flexible substrate 110 refers to a substrate made of a material having flexibility and low light transmittance, and thus does not transmit laser light. The flexible substrate 110 is made of a material such as metal or plastic, and is, for example, aluminum foils, SUS foils, translucent films, or the like.

The back electrode 121 is formed on the flexible substrate 110 using a metal or a transparent conductive material (TCO), such as silver, aluminum, silver + aluminum, silver + magnesium, silver + manganese, silver + germanium, silver + Zinc, silver + molybdenum, silver + nickel, silver + copper or silver + aluminum + zinc, transparent conductive materials such as indium tin oxide (ITO), fluorine doped tin oxide (FTO), zinc oxide, doped Zinc boride (ZnO: B), aluminum-doped zinc oxide (ZnO: Al), Ag, tin dioxide (SnO2), fluorine-doped tin dioxide (SnO2: F), zinc oxide: gallium trioxide (ZnO: Ga2O3) Zinc oxide: aluminum oxide (ZnO: Al2O3) or tin dioxide: antimony trioxide (SnO2: Sb2O3).

The anti-diffusion layer 122 prevents the material of the back electrode 121 from being diffused into the semiconductor layer 150 arranged on the back electrode 121, and contributes to an improvement in the efficiency of the solar cell. The anti-diffusion layer 122 is made of a conductive material such as zinc oxide, boron-doped zinc oxide (ZnO: B), aluminum-doped zinc oxide (ZnO: Al), germanium (Ge), aluminum oxide (Al 2 O 3 ) or cerium oxide (SiO 2 ). ) Manufacturing. The anti-diffusion layer 122 may also be omitted.

Next, the first laser scribe is completed to divide the back electrode 121 into a plurality of unit back electrodes. The laser scribing does not require a mask to divide the back electrode 121 into a plurality of unit back electrodes, thereby having an economic advantage in the manufacturing process of the thin film type solar cell.

The flexible substrate 110 is fabricated from a material that does not transmit laser light. For this reason, the first laser scoring is performed by directly irradiating the laser to the back electrode 121 and the anti-diffusion layer 122.

Please refer to "Fig. 6b", the first trench t1 is formed in the area cleared by the first laser scribing. The particles of the back electrode 121 and the anti-diffusion layer 122 removed by the first laser scoring appear as a residue on the anti-diffusion layer 122, or are melted by the high energy of the laser and laminated on both sides of the first trench t1. On the edge of the anti-diffusion layer 122 appearing thereon, a burr 125 is produced.

The burrs 125 have a height of several hundred nanometers. Referring to "figure 5", the burr 73 penetrates the semiconductor layer 74 and contacts the front electrode 75, thereby interfering with the insulation of the solar cell and causing a decrease in the efficiency of the solar cell.

Please refer to "Fig. 6c" to complete the second laser scribing to remove the burrs 125 arranged on the side of the first trench t1. The second laser scribe can be performed using the same laser device as the first laser scribe.

Referring to "Fig. 6d", the burrs 125 appearing on the side of the first trench t1 are removed by the second laser scribe. At this time, a portion of the edge of the anti-diffusion layer 122 is removed, and the cleared region forms a step 126.

Referring to "Fig. 6e", three laser scribings are completed to clear the burrs 125 appearing on the other side of the first trench t1. Three laser scribes can be completed simultaneously with the second laser scribe. Three laser scorings (three times laser scribing) can be performed using the same laser device as the first laser scoring.

Referring to "Fig. 6f", the burrs 125 arranged on the other side of the first trench t1 are removed by three laser scribes. At this time, a portion of the edge of the anti-diffusion layer 122 is removed, and the cleared region forms a step 126.

Referring to FIG. 6g, the semiconductor layer 130 is formed on the anti-diffusion layer 122. The semiconductor layer 130 is formed to have a NIP structure in which an n-type semiconductor layer, an i-type semiconductor layer, and a p-type semiconductor layer are laminated in this order.

Referring to "Fig. 6h", the P2 laser scribe is completed to divide the semiconductor layer 130 into a plurality of unit semiconductor layers. The second trench (t2) is formed by P2 laser scribing.

Referring to FIG. 6i, the front electrode 140 is formed on the semiconductor layer 130 including the second trench t2. The front electrode 140 includes a surface on which sunlight is incident, and the front electrode 140 is made of, for example, zinc oxide, boron-doped zinc oxide (ZnO: B), aluminum-doped zinc oxide (ZnO: Al), tin dioxide (SnO 2 ), or It is made of a transparent conductive material of fluorine tin dioxide (SnO2:F) or indium tin oxide (ITO).

Referring to "Fig. 6j", the laser scribing is completed to divide the front electrode 140 into a plurality of unit front electrodes. The third trench t3 is formed by P3 laser scribing. Therefore, the solar cell has a structure in which a plurality of unit cells are connected in series.

As described above, the process of removing the back electrode 121 and the anti-diffusion layer 122 arranged on the flexible substrate 110 to form the first trench t1 by laser scribing (this process is referred to as 〞P1 laser scribe 〞) The high energy melted particles of the laser are laminated on the edges of the anti-diffusion layer 122 to produce a burr 125. In the laser scribing process for processing particularly important materials, the burrs 125 are severe. The burrs 125 should be removed to insulate the solar cells. In the conventional case, the burr 125 is removed through an additional cleaning process.

According to the preparation method of the solar cell, the burr 125 generated during the P1 laser scribing process can be used by the additional second and third laser scribing processes using the laser used in the first laser scribing process without using any other equipment. Clear. Therefore, the problem of deterioration of insulation and efficiency of the solar cell caused by the burr 125 can be easily solved.

The method of the present invention does not require an additional wet cleaning process to remove burrs (by-products), thereby reducing the time and cost involved therein. In addition, the water sensitive flexible substrate requires a separate drying process after the wet cleaning process, but the method of the present invention omits the drying process, thereby reducing the time and cost involved in solar cell fabrication.

The embodiment in which the burr 125 generated during the P1 laser scribing is removed by a series of laser processes is applied to remove the burrs generated during the P1 laser scribing and the burrs generated during the P2 laser scoring, and P3 The burrs generated during the laser scribing, wherein the P2 laser scribing is completed to divide the semiconductor layer 130 into a plurality of unit semiconductor layers, and the P3 laser scribing is completed to divide the front electrode 140 into a plurality of unit front electrodes 140.

Fig. 7 is a schematic view showing the completion process of laser scribing in the method for manufacturing a solar cell according to an embodiment of the present invention.

Please refer to "6a", "6b", "6c", "6d", "6e", "6f", "6g", "6h", In the "6th drawing", the "6th drawing", and the "7th drawing", first, the back electrode 121 is removed by the first laser scribe to divide the back electrode 121 into a plurality of unit back electrodes. The back electrode 121 on which the anti-diffusion layer 122 is formed is intended to include the anti-diffusion layer 122 (refer to "Fig. 6a").

The first line L1 is formed along the back electrode 121 which is removed by the first laser scribing. The first laser scribing is performed with high frequency and high power with a large width. The first line L1 has a width (W1) of 50 to 60 micrometers (μm.).

Then, the second laser scribing is completed to clear the burrs generated by the first laser scribing on one side of the first line L1, such that the processing area of the second laser scribing overlaps with the first line L1. The second laser scribe is performed by setting the center of the laser to one side of the first line L1. Compared to the first laser scoring, the second laser scoring is performed in accordance with low frequency and low power of small width.

The second line L2 is formed by secondary laser scribing. The second line L2 has a width of 20 to 30 micrometers (μm.). At this time, the width of the overlapping area of the first line L1 and the second line L2 is 10 to 15 μm, which is 1/2 of the width W2 of the second line L2, which is 1/4 of the width W1 of the first line L1 or less.

Then, three laser scribings are completed to clear the burrs generated by the first laser scribing on the other side of the first line L1, such that the processing area of the three laser scoring overlaps the first line L1. Three laser scribings are performed by setting the center of the laser as the other side of the first line L1. Compared to the first laser scoring, the three-shot laser scoring is performed in accordance with low frequency and low power of small width.

The third line L3 is formed by three laser scoring. The third line L3 has a width of 20 to 30 microns. At this time, the width of the overlapping area of the first line L1 and the second line L2 is 10 to 15 μm, which is 1/2 of the width W3 of the third line L3.

Thus, the burrs are effectively removed by performing three laser scribes such that the processing area of the three laser scribes partially overlaps the formed first line L1. When the second and third laser scribes are performed with low frequency and low power at a low power compared to the first laser scribe, only the burrs can be effectively removed without any influence on the back electrode 121.

The "Fig. 8" is a schematic view showing a state in which the burr is removed by laser scribing in an embodiment shown in Fig. 7.

Referring to "Fig. 4", a burr 73 is formed on the diffusion resistant layer 72. On the other hand, please refer to "Fig. 8", the anti-diffusion layer 122 is completely removed, and its edge forms a small step.

Fig. 9 is a cross-sectional view showing a solar cell according to an embodiment of the present invention.

The substrate 110 is made of a material having flexibility and low transmittance. The substrate 110 may be made of metal or plastic such as aluminum foil, SUS foil, translucent film, or the like.

The back electrode 121 is formed on the substrate 110. The back electrode 121 is formed of a metal or a transparent conductive material (TCO) such as silver, aluminum, silver + aluminum, silver ten magnesium, silver + manganese, silver + germanium, silver + zinc, silver + molybdenum, silver + nickel, silver. + copper or silver + aluminum + zinc, transparent conductive materials such as indium tin oxide (ITO), fluorine doped tin oxide (FTO), zinc oxide, boron doped zinc oxide (ZnO: B), aluminum doped Zinc oxide (ZnO: Al), Ag, tin dioxide (SnO2), fluorine-doped tin dioxide (SnO2: F), zinc oxide: gallium oxide (ZnO: Ga2O3), zinc oxide: aluminum oxide (ZnO) :Al2O3) or tin dioxide: antimony trioxide (SnO2: Sb2O3).

The anti-diffusion layer 122 is formed on the back electrode 121. The anti-diffusion layer 122 prevents the material of the back electrode 121 from being diffused into the semiconductor layer, thereby improving the efficiency of the solar cell. The anti-diffusion layer 122 is made of, for example, zinc oxide, boron-doped zinc oxide, aluminum-doped zinc oxide, germanium (Ge), aluminum oxide (Al 2 O 3 ), or hafnium oxide (SiO 2 ). The anti-diffusion layer 122 may also be omitted.

The back electrode 121 and the anti-diffusion layer 122 are spaced apart through the first trench t1. The first trench t1 is formed by P1 laser scribing.

The edge of the anti-diffusion layer 122 adjacent to the first trench t1 has a step 126 lower than the anti-diffusion layer 122. Step 126 is formed through a series of laser processes to remove burrs generated during P1 laser scoring. The width of the step 126 is 1/4 or less of the width of the first trench t1.

In the case where the anti-diffusion layer 122 is not formed, the edge of the back electrode 121 adjacent to the first trench t1 has a step.

The semiconductor layer 130 is formed over the anti-diffusion layer 122 including the first trench t1. The semiconductor layer 130 has a NIP structure in which an n-type semiconductor layer, an i-type semiconductor layer, and a p-type semiconductor layer are laminated in this order.

The semiconductor layer 130 is spaced through the second trench (t2). The second trench (t2) is formed by P2 laser scribing.

The front electrode 140 is formed over the semiconductor layer 130. The sunlight is incident on the surface of the front electrode 140, and the front electrode 140 is made of zinc oxide, boron-doped zinc oxide (ZnO: B), aluminum-doped zinc oxide (ZnO: Al), tin dioxide (SnO2), fluorine-doped It is made of a transparent conductive material such as tin oxide (SnO2:F) or indium tin oxide (ITO).

The front electrodes 140 are spaced through the third trench t3. The third trench t3 is formed by P3 laser scribing.

"10a", "10b", "10c", "10d", "10e" and "10f" are manufacturing processes for solar cells according to an embodiment of the present invention. Schematic diagram. The same components as in the embodiment shown in "6a", "6b", "6c", "6d", "6e", and "6f" are given the same reference. The reference numerals are given, and detailed descriptions thereof are omitted.

Referring to FIG. 10a, the back electrode 121 and the anti-diffusion layer 122 are formed on the substrate 110. Then, the first laser scribing is completed to divide the back electrode 121 into a plurality of unit back electrodes.

Please refer to "Fig. 10b", the first trench t1 is formed in the region cleared by the first laser scribing. The particles of the back electrode 121 and the anti-diffusion layer 122 removed by the first laser scribing appear as a residue on the anti-diffusion layer 122, or are melted by the high energy of the laser and laminated on both sides of the first trench t1. On the edge of the anti-diffusion layer 122 appearing thereon, a burr 125 is produced.

Referring to "Fig. 10c", the second laser scribing is completed to clear the burrs 125 arranged on the side of the first trench t1. At this time, the back electrode 121 and the anti-diffusion layer 122 under the burr 125 are removed. The second laser scoring is performed using the same laser device as the first laser scoring.

Referring to "Fig. 10d", the burrs 125 arranged on the side of the first trench t1 and the back electrode 121 and the anti-diffusion layer 122 arranged therebelow are removed by secondary laser scribing.

Referring to "Fig. 10e", three laser scribings are completed to clear the burrs 125 appearing on the other side of the first trench t1. At this time, the back electrode 121 and the anti-diffusion layer 122 appearing under the burr 125 are removed. Three laser scribes and two laser scribes can be completed simultaneously. The three-shot laser scoring is performed using the same laser device as the first laser scoring.

Referring to FIG. 10f, the burrs 125 arranged on the other side of the first trench t1 and the back electrode 121 and the anti-diffusion layer 122 arranged under the burrs 125 are removed by three laser scribing.

Since the burr 125 is removed along with the back electrode 121 and the anti-diffusion layer 122 arranged under the burr 125 by the second and third laser lithography, this embodiment and "Fig. 6a", "6b", "6c" The embodiments shown in Fig., "6d", "6e", and "6f" are different.

"11a", "11b", "11c" and "11d" are schematic views of a manufacturing process of a solar cell according to another embodiment of the present invention. The same elements as those in the embodiments shown in "6a," "6b," "6c," "6d," "6e," and "6f" are denoted by the same reference numerals. And a detailed description thereof is omitted.

Referring to FIG. 11a, the back electrode 121 and the anti-diffusion layer 122 are formed on the substrate 110. Then, the first laser scribing is completed to divide the back electrode 121 into a plurality of unit back electrodes.

Please refer to "Fig. 11b", the first trench t1 (or the first line) is formed in the area cleared by the first laser scribing. The particles of the back electrode 121 and the anti-diffusion layer 122 removed by the first laser scribing appear as a residue on the anti-diffusion layer 122, or are melted by the high energy of the laser and laminated on both sides of the first trench t1. On the edge of the anti-diffusion layer 122 appearing thereon, a burr 125 is produced.

Referring to "Fig. 11c", the second laser scribing is completed to clear the burrs 125 arranged on both sides of the first trench t1. At this time, only the burrs 125 are removed, and the back electrode 121 and the anti-diffusion layer 122 arranged under the burrs 125 are also removed.

The second laser scoring is continuously performed along the first line formed by the first laser scoring, such that the treated area of the second laser scoring overlaps the first line. Therefore, the area of the area where the second laser scribe is completed is larger than the area of the area where the first laser scribe is completed. The second laser scoring is performed using the same or a different device as the first laser scoring.

Referring to FIG. 11d, the burrs 125 arranged on both sides of the first line and the back electrode 121 and the anti-diffusion layer 122 arranged under the burrs 125 are removed by the second laser scribe.

In this embodiment, the burrs 125, which are first scribed on both sides of the first line, are removed by the second laser scribe, thereby simplifying the process and shortening the process time.

Fig. 12 is a schematic view showing a comparison between a conventional device for manufacturing a solar cell and the device of the present invention.

Referring to "Fig. 9" and "Fig. 12", in the schematic view of the configuration of the conventional device, the first sputtering machine or the chemical vapor deposition apparatus for forming the back electrode 121 is arranged on the substrate 110.

A second sputtering machine or chemical vapor deposition apparatus for forming the anti-diffusion layer 122 on the back electrode 121 is arranged in the vicinity of the first sputtering machine or the chemical vapor deposition apparatus.

The P1 processed laser is arranged adjacent to a second sputtering machine or chemical vapor deposition apparatus to complete the P1 laser scoring.

A cleaning device for removing burrs generated during P1 laser scribing is arranged near the P1 processing laser.

A plasma enhanced chemical vapor deposition (PECVD) apparatus for forming the semiconductor layer 130 on the anti-diffusion layer 122 is arranged in the vicinity of the cleaning device to remove the burrs. Plasma enhanced chemical vapor deposition is a method of depositing a film by plasma using ion activation.

The P2 processed laser used to complete the P2 laser scoring is arranged adjacent to the plasma enhanced chemical vapor deposition apparatus. A third sputtering machine or chemical vapor deposition apparatus for forming the front electrode 140 on the semiconductor layer 130 is arranged in the vicinity of the P2 processing laser. The P3 processed laser used to complete the P3 laser scoring is arranged adjacent to the third sputtering machine or chemical vapor deposition apparatus.

In the meantime, in the configuration diagram of the apparatus to which the present invention is applied, the plasma enhanced chemical vapor deposition apparatus is arranged in the vicinity of the P1 processing laser, thereby avoiding the necessity of cleaning any cleaning equipment for removing the burrs. This is why the burrs generated during the P1 laser scoring can be easily removed by first, second and third laser scoring using the P1 processed laser.

The present invention provides a solar cell manufacturing apparatus which is relatively simple in configuration as compared with conventional wet cleaning and drying processes for removing burrs. Furthermore, the present invention can greatly shorten the total process time required to manufacture a solar cell, thereby reducing manufacturing costs.

As apparent from the above, the present invention provides a solar cell and a method of fabricating the same, wherein the deterioration of the insulation and efficiency of the solar cell can be avoided by a series of laser processes by removing the burrs generated during the P1 laser scribing.

Although the present invention has been disclosed above in the foregoing embodiments, it is not intended to limit the invention. It is within the scope of the invention to be modified and modified without departing from the spirit and scope of the invention. Please refer to the attached patent application for the scope of protection defined by the present invention.

10. . . Substrate

20. . . Front electrode

30. . . Semiconductor layer

T1. . . First groove

T2. . . Second groove

T3. . . Third groove

50. . . Back electrode

60. . . Substrate

61. . . Transparent conductive layer

70. . . Substrate

71‧‧‧ Back electrode

72‧‧‧Anti-diffusion layer

73‧‧‧Mamma

74‧‧‧Semiconductor layer

75‧‧‧ front electrode

110‧‧‧Flexible substrate

121‧‧‧Back electrode

122‧‧‧Anti-diffusion layer

125‧‧‧Mamma

126‧‧‧ ladder

130‧‧‧Semiconductor layer

140‧‧‧ front electrode

L1‧‧‧ first line

L2‧‧‧ second line

L3‧‧‧ third line

W1, W2, W3‧‧‧ width

1a to 1f are cross-sectional views showing a method of manufacturing a conventional thin film type solar cell having a structure in which a plurality of unit cells are connected in series;

Figure 2 is a schematic view showing a laser scribing method for a conventional solar panel;

Figure 3 is a schematic view showing a laser scribing method for a conventional substrate type solar cell;

Figure 4 is a schematic view showing the burrs generated by laser scribing in a conventional substrate type solar cell;

Fig. 5 is a schematic view showing a problem caused by burrs in a conventional substrate type solar cell;

6a to 6j are schematic views showing a manufacturing process of a solar cell according to an embodiment of the present invention;

Figure 7 is a schematic view showing a laser scribing process in a method of manufacturing a solar cell according to an embodiment of the present invention;

Figure 8 is a schematic view showing a state in which the burr is removed by laser scribing in an embodiment shown in Figure 7;

Figure 9 is a cross-sectional view showing a solar cell according to an embodiment of the present invention;

10a to 10f are schematic views showing a manufacturing process of a solar cell according to an embodiment of the present invention;

11a to 11d are schematic views showing a manufacturing process of a solar cell according to another embodiment of the present invention;

Figure 12 is a schematic view showing a comparison between a conventional device for manufacturing a solar cell and the device of the present invention.

T1. . . First groove

T2. . . Second groove

T3. . . Third groove

110. . . Flexible substrate

121. . . Back electrode

122. . . Anti-diffusion layer

126. . . ladder

130. . . Semiconductor layer

140. . . Front electrode

Claims (14)

A method for manufacturing a solar cell, comprising: forming a back electrode on a substrate; forming an anti-diffusion layer on the back electrode; completing a first laser scribe to form a first pass through the back electrode and the anti-diffusion layer a trench divides the back electrode into a plurality of unit back electrodes; and performs a second laser scribe along one side of the first line formed by the first laser scribe, such that the processing area of the second laser scribe Overlapping the first line to remove a burr generated by the first laser scribe; and performing three laser scribes along the other side of the first line, such that the processing area of the three laser scribes is the first The lines overlap to remove the burr, wherein the second laser scribe and the three laser scribes are performed such that an edge of the anti-diffusion layer adjacent to the first trench has a step equal to or lower than the resistance The top of the diffusion layer. The method of manufacturing a solar cell according to claim 1, wherein the second laser scribe is performed simultaneously or sequentially with the three laser scribes. The method for manufacturing a solar cell according to claim 1, wherein a line formed by the second laser scribe is defined as a second line, and a line formed by the third laser scribe is defined as a third line. The width of the second line and the third line is 1/2 or less of the width of the first line. The method for manufacturing a solar cell according to claim 3, wherein the second line And the width of the third line overlaps the width of the first line by about 10 micrometers (μm) or more. The method of fabricating a solar cell according to claim 3, wherein the first line has a width of about 50 to about 60 microns, and the second line and the third line have a width of about 20 to about 30 microns. The method of manufacturing a solar cell according to claim 1, wherein the second laser scribe and the three laser scribes are performed according to a low frequency and a low power compared to the first laser scribe . The method of manufacturing a solar cell according to claim 1, wherein the substrate is a flexible substrate selected from the group consisting of an aluminum foil, a SUS foil, and a semi-transparent film. The method for manufacturing a solar cell according to claim 1, wherein the back electrode is selected from the group consisting of silver, aluminum, silver+aluminum, silver+magnesium, silver+manganese, silver+germanium, silver+zinc, silver+molybdenum, A group consisting of silver + nickel, silver + copper, and silver + aluminum + zinc. The method for manufacturing a solar cell according to claim 1, wherein the anti-diffusion layer comprises zinc oxide, boron-doped zinc oxide (ZnO: B), aluminum-doped zinc oxide (ZnO: Al), germanium (Ge), and the like. Any one of aluminum oxide (Al ₂ O ₃ ) or cerium oxide (SiO ₂ ). A method for manufacturing a solar cell, comprising: forming a back electrode on a substrate; performing a first laser scribe to divide the back electrode into a plurality of unit back electrodes by forming a first trench in the back electrode; One of the first lines formed by the first laser scoring completes the second thunder Shooting, such that the processing area of the second laser scoring overlaps the first line to remove a burr generated by the first laser scoring; and completes three laser engravings along the other side of the first line So that the processing area of the three laser scribes overlaps the first line to remove the burr, wherein the second laser scribe and the three laser scribes are performed to make the back electrode adjacent to the first trench The edge has a step that is equal to or lower than the top of the back electrode. A method for manufacturing a solar cell, comprising: forming a back electrode on a substrate; forming an anti-diffusion layer on the back electrode; completing a first laser scribe to form a first pass through the back electrode and the anti-diffusion layer a trench divides the back electrode into a plurality of unit back electrodes; and performs a second laser scribe along both sides of a first line formed by the first laser scribe, such that the second laser scribes The processing area overlaps the first line to remove a burr generated by the first laser scribe, wherein the second laser scribe is performed to have a step of the edge of the anti-diffusion layer adjacent to the first trench The step is equal to or lower than the top of the anti-diffusion layer. The method of manufacturing a solar cell according to claim 11, wherein an area of the area where the second laser scribe is completed is larger than an area of the area where the first laser scribe is completed. A solar cell comprising: a substrate; a back electrode and an anti-diffusion layer are separated by a first trench on the substrate; and a semiconductor layer is passed through a second trench on the anti-diffusion layer ( T2) is spaced apart; and a front electrode is spaced through a third trench on the semiconductor layer, wherein an edge of the anti-diffusion layer adjacent to the first trench comprises a portion equal to or lower than a top of the anti-diffusion layer One of the steps. The solar cell of claim 13, wherein the width of the step is 1/4 or less of a width of the first trench.