WO2014184971A1

WO2014184971A1 - Foreign object removal device and method for producing solar cell using same

Info

Publication number: WO2014184971A1
Application number: PCT/JP2013/079148
Authority: WO
Inventors: 光徳中谷; 黒田　章裕; 浅野　聡也; 聖沖本
Original assignee: 三菱電機株式会社
Priority date: 2013-05-14
Filing date: 2013-10-28
Publication date: 2014-11-20
Also published as: JPWO2014184971A1; TWI514610B; JP6091610B2; WO2014184876A1; TW201507188A

Abstract

In the present invention, a rotating brush (37) of soft hairs produced at high precision and having an outer diameter equivalent to a texture size is contacted to a solar cell (10) immediately after CVD film production by an amount corresponding to the texture size, p-n junction breakage resulting from texture chipping is avoided, and only CVD foreign objects such as foreign object microparticles (14) and foreign object coarse particles (14G) are eliminated by means of the rotational force of the rotating brush (37). As a result, it is possible to produce a solar cell without a brush material adhering to the cell surface in a manner so as to cause problems in a printing step or in a manner so as to cause scratches at the cell surface, even while eliminating CVD foreign objects that lead to a hindrance in the printing of a grid electrode having a width of 30-150 μm.

Description

Foreign matter removing apparatus and method for manufacturing solar cell using the same

The present invention relates to a foreign matter removing apparatus and a solar battery manufacturing method using the same, and more particularly, to a brush device that removes foreign matter adhering to the surface of a solar battery cell.

For example, a solar battery cell is formed on a silicon substrate, a pn junction that converts light energy of sunlight into electrical energy, an antireflection film that is provided on the substrate on the light-receiving surface side and suppresses reflection of sunlight, and antireflection A collector electrode provided on the film and outputting electric energy to the outside is formed. In many cases, the antireflection film is formed of silicon nitride, and a plasma CVD apparatus is used for the film formation.

When a silicon nitride film is formed on a silicon substrate as a substrate to be processed using a plasma CVD apparatus, the film is also formed on the inner wall, electrode, and stage inside the apparatus at the time of film formation. Then, these films are peeled off to become foreign substances, and fall onto the silicon substrate before, during or during processing. If foreign matter adhering in the process of forming the antireflection film is present on the silicon substrate, the current collecting electrode cannot be formed in a desired pattern when the current collecting electrode is formed by screen printing in the next process. Furthermore, foreign matter adheres to the pattern portion of the print mask, causing clogging. If pattern formation is performed using this print mask, the collector electrode cannot be formed in a desired pattern on another silicon substrate. Sometimes. That is, the same defect may occur even in a solar battery cell to which no foreign matter is attached. In order to suppress such defects, the printing mask is periodically replaced. However, there is a problem that productivity is reduced due to an increase in printing mask cost and time required for the replacement.

For example, a method of forming an antireflection film having a thickness of 60 nm to 95 nm by a plasma CVD (Chemical-Vapor-Deposition) method is disclosed (for example, Patent Document 1). In this method, when the number of times of film formation increases, the plasma CVD apparatus deposits a film made of the same material as the antireflection film in the chamber and peripheral jigs, and the film peels off and becomes a foreign substance and falls into the cell to cause a defect. cause. After the CVD film is formed, the foreign matter comes out on the cell with a size of 1 mm or less. As for the particle size distribution of the foreign matter, 10 μm or less is 95% or more. In the electrode forming step after the CVD film is formed, a comb-like grid electrode having a width of 30 μm to 150 μm is printed by a screen printing method. At this time, if a foreign substance having a size equal to or larger than the grid width blocks the opening of the mask, a printing defect occurs and cell characteristic defects continuously occur.

As for foreign matters after the CVD film formation, those having a size of 0.1 mm or more can be removed by air blow, but those having a size of 0.1 mm or less cannot be removed by air blow.

By the way, solar cells form a pyramid-like texture in order to confine sunlight efficiently. When the texture is formed with an alkali or acid type wet solution, the texture step is generally 1 μm to 30 μm. When the texture is formed by a dry etching technique using plasma, the texture is 0.5 μm to 3 μm. There are many.

When observing the state in which one foreign substance of several μm or more is placed on such a texture, the foreign substance gets on the top of several textures and makes point contact to form a point contact part. As a result of proceeding with the analysis investigation, foreign matter gets on the cell during the CVD film formation, and the CVD film is slightly deposited on the foreign matter, and the point contact portion is protected by the underlying cell and the CVD film having a thickness of several nm. It seems that it is difficult to remove. If the CVD foreign matter is to be removed with a hard object, the pn junction formed on the surface of the solar battery cell is destroyed with a size equivalent to the size of the foreign matter, and the cell output is significantly deteriorated. This CVD foreign matter can be easily removed by applying a force of about 0.1 N, but it is understood that with a general cell size of 156 mm □, several thousand foreign matters of 10 μm to 100 μm are carried on one cell. The foreign particles increase exponentially as the particle size decreases. It takes too much time to remove such countless foreign substances one by one, which is a major obstacle to production. For this reason, it is necessary to pay a great deal of labor for the maintenance of the chamber of the CVD film forming apparatus. Examples of the occurrence of CVD foreign matter are disclosed in Patent Document 2 and the like.

Also, a method of cleaning foreign matter in the CVD chamber with a charging plate is disclosed (Patent Document 3).

Further, Patent Document 4 discloses a rotating brush. In this example, a protective film used in the production of a solar cell using a CdTe film is adhered to a hard resin rotating shaft and rubbed to remove it. Even if this apparatus is used for removing CVD foreign matter, the cell surface Is markedly scratched, leading to deterioration of characteristics.

In addition, the present inventors tried to remove the CVD foreign matter by rubbing the cell surface with a net or cloth formed of a soft resin made of vinyl, but even if the foreign matter could be removed, clear streak marks that can be visually recognized on the cell surface. I knew I could enter. In some cases, the pn junction in the texture portion was broken, or vinyl adhered to the top of the texture. When vinyl adheres to the textured shape, CVD foreign matter may adhere to the print mask and become clogged in the printing process, as in the case where CVD foreign matter has adhered.

Japanese Patent No. 4144241 Japanese Patent No. 3651977 JP 2009-144193 A Japanese Patent Laid-Open No. 2001-15777

The present invention has been made in view of the above, and while removing CVD foreign matter that interferes with printing of fine line widths such as grid electrode widths of 30 μm to 150 μm, the cell surface is scratched or troubles occur in the printing process. An object of the present invention is to obtain a foreign matter removing apparatus that does not cause the brush material to adhere to the cell surface and a method for producing a solar cell using the same.

In order to solve the above-described problems and achieve the object, the foreign matter removing device of the present invention is a foreign matter removing device for removing foreign matter adhering to the surface of the solar battery cell, holding the solar battery cell on a smooth surface. Conveying part to convey and a large number of non-metallic hairs, contact with the solar cells on the conveying part to remove foreign matter, contact with the brush and adhere to the brush And a wiping plate for wiping off the foreign matter.

According to the present invention, since the foreign matter is removed while removing the foreign matter adhering to the brush using the brush and the wiper plate, the pn junction breakage due to the lack of texture is avoided, and the printing process is performed. It is possible to prevent the occurrence of a defect. As a result, it is possible not only to improve the cell non-defective rate and the productivity, but also to form a fine grid electrode even in a fine region with a large distribution of CVD foreign matter. Therefore, the cell output can be improved and the cost can be reduced, and high-quality solar cells can be provided with high productivity.

FIG. 1 is a schematic diagram of a foreign matter removing apparatus using a rotating brush device according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of the AA cross-sectional view of FIG. 1, which is a foreign matter removing apparatus using a rotating brush device according to the first embodiment of the present invention. FIG. 3 is a schematic view of a rotating brush device without a cell edge receiving roller. FIG. 4 is an enlarged view of a main part of FIG. FIG. 5 is a schematic diagram when the tip of the rotating brush is disturbed. FIG. 6 is a schematic diagram for obtaining the outer diameter accuracy by rotating the rotating brush at a high speed to straighten the hair tips and cutting the hair tips. 7A and 7B are diagrams showing a turntable type printing stage, where FIG. 7A is a layout and function diagram, and FIG. 7B is a schematic diagram of a foreign matter removing apparatus using a flat brush. FIG. 8 is a diagram for explaining the configuration of the solar battery cell according to the third embodiment of the present invention, in which (a) is a cross-sectional view, (b) is a top view, and (c) is a bottom view. FIG. 9 is a flowchart for explaining a manufacturing process of the solar battery cell according to the third embodiment of the present invention. 10 (a) to 10 (g) are cross-sectional views for explaining the manufacturing process of the solar battery cell according to the third embodiment of the present invention. FIGS. 11A to 11C are process cross-sectional views illustrating the foreign matter removing process according to the third embodiment of the present invention. FIG. 12 is a schematic diagram of a foreign matter removing apparatus using a rotating brush device according to a fourth embodiment of the present invention. FIG. 13 is a schematic diagram of a foreign matter removing apparatus using a rotating brush device according to a fifth embodiment of the present invention. FIG. 14 is a schematic diagram of a foreign matter removing apparatus using a rotating brush device according to a sixth embodiment of the present invention.

Embodiments of a foreign matter removing apparatus and a solar cell manufacturing method using the same according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the drawings shown below, the scale of each member may be different from the actual scale for easy understanding. The same applies between the drawings.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of a foreign matter removing apparatus using the rotating brush device according to the first embodiment of the present invention. This foreign matter removing apparatus includes a solar battery cell (hereinafter also referred to as a cell) after CVD film formation. It is mounted on a transport belt 20 for transport. This foreign matter removing device is a device for removing foreign matter adhering to the surface of a cell 10 constituting a solar battery, and removes foreign matter by bringing it into contact with the transport belt 20 as a transport section and the cell 10 on the transport belt 20. The rotating brush 37, the wiper plate 40 which contacts the rotating brush 37 and wipes off the foreign matter attached to the rotating brush 37, and a cleaning unit are included. The conveyance belt 20 conveys the cell 10 while holding the cell 10 on a smooth surface. The rotating brush 37 is made of a high-molecular fiber made of a large number of non-metallic hairs and having a hardness lower than that of silicon, which is a substrate for a solar battery constituting a solar battery cell. The cleaning unit cleans the tip of the rotating brush 37 by blowing air at a speed larger than the floating speed of the foreign matter to be removed. FIG. 4 is an enlarged view of a main part of FIG. In this solar cell 10, an n-type impurity diffusion layer 3 is formed by phosphorus diffusion as a second conductivity type semiconductor layer on the light-receiving surface side of a p-type single crystal silicon substrate as a substrate 2, and a semiconductor having a pn junction. A substrate 11 is configured. Thus, the antireflection film 4 is formed on the surface of the substrate 2 on which the n-type impurity diffusion layer 3 is formed by the CVD film forming method.

First, the outline of the function of FIG. 1 is that the cell 10 on the transport belt 20 is transported, and the coarse foreign particles 14G are removed and collected to the first dust collector 36 using the air blow 35 in the first stage, and in the second stage. Using the rotating brush 37, the foreign particle 14 adhering to the cell 10 is removed and collected in the second dust collector 41. During the rotation of the rotating brush 37, the foreign matter coarse particles 14G and the foreign matter fine particles 14 sandwiched between the hairs of the rotating brush 37 between the hairs and the hairs are not subjected to static electricity removal measures and do not contain metal. The tip of the rotary brush 37 is wiped off with the conductive wiper 40 or blown off by the air blow 42 on the tip of the rotary brush 37 and collected by the second dust collector 41 or the third dust collector 43. Here, the duct cross-sectional area of the collection path to the first dust collector 36, the second dust collector 41, and the third dust collector 43 is kept constant to collect the foreign matter that has been moved or floated by brushing or air blow. It is desirable to do. In particular, it is desirable that the cover 44 be a cylindrical body having a constant cross section and the duct cross-sectional area be constant in the vicinity of the rotating brush 37. Here, the vicinity of the rotating brush 37 refers to a portion in a cross section perpendicular to the rotating shaft 39 of the rotating brush 37, and is formed to be a cylindrical body having a constant cross section at least in this region. Thus, by making the duct cross-sectional area constant, it becomes possible to efficiently maintain the flow velocity to the first dust collector 36, the second dust collector 41, and the third dust collector 43 while maintaining a laminar flow state. It is possible to suppress the foreign matter flying at the limit of the floating speed from falling and accumulating at an unexpected place due to the decrease in the airflow speed. Here, a so-called anti-static plate is effective as the conductive deburring plate 40 that does not contain metal and has been subjected to static electricity removal measures. For example, a material obtained by conducting a conductive treatment on the surface of a PVC (polyvinyl chloride) substrate is used as the antistatic plate.

Next, the details of each function of the rotating brush will be described mainly with reference to FIG. Although not shown, the conveyance belt 20 is provided with several suction holes of 1 to 3 mmΦ per cell. By suctioning through the suction holes, suction is performed at a negative pressure of several tens of kPa per cell. Yes. The suction hole prevents the cell 10 from being displaced on the conveyor belt 20, and when removing the cell 10 from the conveyor belt 20, the suction is turned off and the negative pressure is released. In FIG. 1, the cell 10 is moved from the left to the right in the drawing by the conveyor belt 20. There are various movement methods. (1) When the speed is constant, (2) When the robot moves by a pitch larger than the cell size, it stops for a certain time and repeats the same movement. (3) In some cases, the combination of (1) and (2). Thus, the conveyance belt 20 and the cell 10 are integrated and repeatedly accelerated and decelerated.

FIG. 1 shows a state in which CVD foreign matters such as foreign matter coarse particles 14G and foreign matter fine particles 14 are placed on the cell 10. The CVD foreign substances are coarse foreign particles 14G that can be suspended and removed by the air flow 35N flowing from the air blow 35 or the gap between the covers 44, and foreign particles 14 that can be removed by the rotating brush 37. When calculating the relationship between the size of the CVD foreign matter particle and the floating speed, if the antireflection film 4 is a SiNOH film, the floating speed is 0.3 m / sec if the spherical particle has a size of 50 μm, which is a problem in the grid printing process. In the 10 μm size, the floating speed is 0.01 m / sec. The floating speed varies exponentially with the particle size. Large coarse particles with a size of 0.1 mm soar with an air blow of 1 to 2 m / sec.

First, in order to avoid the deterioration of the rotating brush 37 due to the foreign particle coarse particles 14G, air of 2 m / sec or more is blown by the air blow 35 and collected in the first dust collector 36 on the upstream side. A cover 44 is provided so that foreign matter to be collected is not scattered outside.

The rotary brush 37 is preferably made of a general-purpose material of a linear fiber that is soft and has a hardness that does not damage the cell surface, such as vinyl chloride resin or nylon resin. However, if the brush contains metal or the surface is contaminated, the output of the solar cell is greatly deteriorated. For example, in the case of Fe contamination, if the surface of the silicon crystal solar battery cell exceeds 2E12 atoms / cm ² , the cell output is significantly reduced. If the brush material contains 1000 ppm or more of Fe, if the brush marks adhere to the texture surface at a density of 1E-3 / mm ² with a volume of 1 μm ³ , the cell output begins to decrease. A rotating brush 37 is a structure in which several thousand or more hairs are bundled and wound around the rotating shaft 39. The diameter of the hair of the brush should ideally be determined by the size of the foreign matter to be removed and the texture size formed on the cell surface. Limited by. The diameter of the hair of the brush is also determined by the accuracy of the cut surface of the hair tip. Here, if the average size of the target foreign particle 14 to be removed is 50 μm, one hair of the rotating brush is preferably 50 μmΦ and 5 to 40 mm long. Particularly desirable is 10 to 30 mm. The density of the hairs of the brush is 40,000 / cm ² for each hair of 50 μmΦ. In the calculation of the closest cross-sectional area in the cross-sectional direction of the ciliary body, the cross-sectional area density of the ciliary body is π / 4 to 80%. When contacting the cell surface, many hairs contact the cell, and the force applied at that time is 20 Pa, which is sufficiently smaller than the cell breaking stress. The hair cross-sectional area density required for the hair of the brush to be surely removed by contact with foreign matter on the cell surface must be 20% or more.

Next, the foreign particle 14 which is a CVD foreign substance on the cell 10 is rotated by a motor (not shown) on the rotary shaft 39 and brought into contact with the rotary brush 37. Similarly, although not shown in the figure, it is desirable that the rotary brush 37 has a configuration in which the height can be accurately positioned on the micron order by a vertical drive motor. When the rotary brush 37 is pushed into the cell 10 by 3 mm or more and the rotary brush 37 is rotated at a high speed, the hair at the tip of the brush becomes a wholesale state with a hard pyramid-like texture (not shown) of the cell 10, and the hair tip Is scraped off to the top of the texture, and part of it is caught on the top of the texture, and the white streak-like brush marks can be visually observed. In order to suppress scratches, it is desirable that the amount of pushing of the rotating brush 37 into the cell 10 is 0.001 to 3 mm. From the viewpoint of safety, it is desirable that the amount of pushing of the rotating brush 37 into the cell 10 is 0.001 to 0.1 mm. This brush mark induces a printing failure in a later printing process. For this reason, it is desirable to remove foreign matter so that brush marks are not formed. Most brush marks are made of brush material. If it is a grade which does not generate | occur | produce a defect by electrode printing, if it processes in an electrode baking process sufficiently higher than the temperature which a brush material burns, a brush trace will lose | disappear. When heavy metal is contained in the brush material, the cell output decreases, but there is a trade-off relationship with the increase in cell output by removing CVD foreign matter, so the optimum brush push-in amount and brush rotation speed under production conditions It is necessary to decide.

The conveying speed of the conveying belt 20 and the cell 10 is constant 600 mm / s, the hair of the rotating brush 37 is 20 mm long, the outer diameter of the rotating shaft is 40 mmΦ, and the outer diameter of the rotating brush 37 is 80 mmΦ. Then, assuming that the rotation direction is positive in FIG. 1 and the brush is overtaking the cell surface, the relative speed is positive. The relationship between the brush rotation speed and the relative speed between the cell surface is as shown in Table 1. .

From Table 1, it can be seen that the control of the number of rotations is important because the brush marks become apparent when the relative speed of the cell surface with respect to the rotating brush is 600 mm / sec or more. It is desirable to synchronize both the acceleration and deceleration of the drive system of the conveyance belt 20 and the rotating brush 37 so as to correspond to various conveyance modes. In Table 1, the conveyor belt 20 moves at a fairly fast constant speed, and the brush tip and the conveyor belt 20 come into contact with each other and wear. desirable. However, stopping the transport system often significantly reduces productivity.

The parameters that influence the brush mark are the amount of pressing of the brush to the cell, the number of rotations of the brush, the accuracy of the brush outer diameter, and the accuracy of brush pressing control. Here, if the brush rotation speed is lowered, the CVD foreign matter removal rate is likely to be lowered. Therefore, brush marks should be suppressed with other parameters.

Next, the roles of the rotating brush 37 shown in FIG. 1 and the receiving roller 38 shown on the opposite side of the cell 10 will be described. FIG. 2 is a cross-sectional view taken along the line AA in FIG. As shown in FIG. 2, the cell 10 protrudes outward from the conveyor belt 20, and when the rotating brush 37 is pressed, the periphery of the cell 10 warps downward, causing problems such as defective cell adsorption, defective cell conveyance, and broken cells. It becomes. The receiving roller 38 can be synchronized at the same height as the conveying belt 20 as shown in FIG. 2, the rotation direction is opposite to the rotating brush 37 as shown in FIG. 1, and the same peripheral speed as the conveying belt 20. desirable. In particular, when the brush has a protruding portion that protrudes from the cell surface of the solar battery cell, a receiving roller 38 is provided at a location facing the protruding portion, and the cell conveyance system, the receiving roller, and the brush are synchronized. The production yield is improved by forming the synchronous mechanism. FIG. 3 shows a case where the receiving roller 38 is not provided. FIG. 6 is a state diagram before and after the rotating brush 37 is pressed against the cell 10, and when there is no receiving roller 38, the height of the cell periphery outside the conveyor belt 20 moves up and down by 1 mm when the cell thickness is 0.2 mm in high-speed video camera shooting. I know that. This vertical movement around the cell is not recommended when a rotating brush is used at high speed, as it tends to cause brush marks.

Next, even if the accuracy of the pushing amount of the rotating brush 37 and the cell 10 is improved, the brush is an aggregate of thin hair tips of 50 μmΦ. Outer diameter accuracy cannot be obtained, and brush marks are likely to occur. FIG. 5 shows a schematic diagram of a normal rotating brush 45 in which the bristles and hair lengths are not uniform. In the case of FIG. 5, the brush outer diameter is 80 mm ± 2 mm, which is a problem level for brush marks. In order to remove the wrinkles of the hair of the rotating brush 45 in FIG. 5, if the ultra high speed rotation is performed around the rotating shaft 39 in advance, the rotating brush 37 has its hair tips straightened by centrifugal force as shown in FIG. You can take a spear. Furthermore, it has the cutting blade 46 which cuts a hair-like body, and cuts the outer diameter of the rotary brush 37 from which the length of a hair-like body differs in this cut blade 46 to a desired value. When cutting the tip of a brush, the tip is bent due to airflow turbulence if there is a disturbing stationary object because of high-speed rotation. For this reason, it is desirable to use a vacuum when cutting the brush tip.

Since the outer diameter, height, and rotation speed of the rotating brush 37 can be controlled with high accuracy in FIG. 1, when the level is set to the same level as the texture height, the conveyor belt 20 and the receiving roller 38 operate at the same speed in conjunction with the rotating brush 37. Synchronize with. For this reason, even in a region where the relative speed between the cell surface and the brush tip exceeds 600 mm / sec or more, the foreign particle 14 which is a CVD foreign material is bounced by the bristles of the rotating brush 37 and removed into the air. At this time, when the brush bristles begin to rub against the cell surface, the ciliary body is pushed back and most of the ciliary body does not come into contact with the cell surface, so that a brush mark is hardly generated. As described above, the tip cut portion of one hair of the rotating brush can be cut in a vertical section, and the outer diameter of the rotating brush is close to the accuracy of the cut surface of one hair of the rotating brush. . For this reason, the accuracy of the amount of pushing the rotating brush 37 into the cell 10 is close to the diameter of one brush hair, so the outer diameter of one brush hair is reduced, and one hair The longer the length, the better to suppress the brush marks. From such a viewpoint, the outer diameter of the brush hair is preferably 0.2 mm or less. If it exceeds 0.2 mm, the accuracy of the amount by which the rotary brush 37 is pushed into the cell 10 cannot be obtained. However, if the outer diameter of the brush hair is too thin, the processing and operability of the hair tend to be poor.

In FIG. 1, since the foreign particle 14 blown from the surface of the cell 10 by the rotating brush 37 is 50 μmΦ and has a floating speed of 0.3 m / sec, it is exhausted with a larger air volume and collected by the second dust collector 41. The foreign particle coarse particles 14G and the foreign particle 14 may be sandwiched between the hairs of the rotating brush 37 and the hairs. If the surface of the cell 10 is rubbed with the rotating brush 37 in this state, the cell 10 is scratched and the cell output deteriorates. Therefore, it is desirable that the rotating brush 37 is completely wiped off during one rotation.

In FIG. 1, 1 mm of the wiping plate 40 is pushed into the bristles of the rotating brush 37 and applied to wipe off the coarse foreign particles 14G and foreign particles 14 which are CVD foreign matters. The removed foreign matter is collected in the second dust collector 41. When the effect of the wiper plate 40 was confirmed with the rotating brush 37 forcibly mixed with the CVD foreign matter, it was found that several tenths could not be removed. Subsequently, when the air blow 42 was used to blow the tip of the rotating brush 37 at 10 m / sec to 20 m / sec, there were no coarse foreign particles 14G or foreign particles 14 as CVD foreign matters attached to the brush.

As described above, according to the present embodiment, the texture of the texture is determined by pressing the rotating brush produced with the same level of accuracy as the texture size against the cell immediately after film formation of the CVD film by an amount corresponding to the texture size. It is possible to avoid pn junction breakage due to chipping, and to remove only the CVD foreign matter with the rotational force of the brush.

Embodiment 2. FIG.
The rotary brush 37 according to the first embodiment is preferably used for removing foreign substances caused by CVD, but there are cases where foreign substances adhering during conveyance are desired to be removed at the same time in the printing process, which is a subsequent process of the CVD film forming process. Therefore, in this embodiment, a foreign matter removing apparatus using a linear brush (hereinafter referred to as a flat brush) will be described.

7A and 7B show an example of a foreign matter removing apparatus used in the solar cell manufacturing apparatus according to Embodiment 2 of the present invention. FIG. 7A is a diagram showing an overall layout of the printing apparatus when the foreign matter removing apparatus is attached to the printing apparatus, and is a turntable type printing apparatus. The four stages R1 to R4 of the turntable 21 are arranged symmetrically in the vertical and horizontal directions and in point symmetry, and the function of the order in which the cells 10 are supplied and processed is as follows: cell insertion positioning position R1 → brush cleaning position R2 → printing Position R3 → print inspection cell discharge position R4.

FIG. 7B is an enlarged view of a main part showing a brush cleaning position R2 for cleaning the second cell surface. At the brush cleaning position R2, a stage plate 22 is provided on the turntable 21, and the cell 10 is disposed thereon. In FIG. 7B, the turntable 21 rotates and the cell 10 adsorbed on the stage plate 22 is lowered and brought into contact with the flat brush 49 so that the tip of the brush is touched (V ₁ ). is there. In FIG. 7B, the scan is moved from the left to the right (H ₂ ), and when it is finished, it is retracted upward (V ₂ ). Subsequently, the turntable 21 rotates and moves from right to left (H ₁ ) and from top to bottom (V ₁ ) while the cell moves to the next printing position R 3, and returns to the original position. At this time, the foreign material remaining on the flat brush 49 is removed by contacting the wiping plate 40P. The wiping plate 40P is formed so as to be movable up and down, and when the foreign matter remaining on the flat brush 49 is removed, the wiping plate 40P shifts upward and does not come into contact with the flat brush 49. The flat brush 49 may be made of the material, scan speed, and push-in amount described in the first embodiment, but the flat brush 49 corrects wrinkles when the hair tips are bent and wrinkled compared to the rotating brush 37. Is difficult, and the amount of pushing into the cell varies. The flat brush 49 has a life shorter than that of the rotating brush 37 due to scissors, and it is difficult to control the height, but the same effect as that of the rotating brush 37 can be obtained, and the device is simple and easy to use.

A minute scratch on the cell surface induces device characteristics deterioration, but a minute scratch on the back surface of the cell has a likelihood. Here, when a linear brush, that is, a flat brush 49, is used for a horizontal moving part such as a belt transporter, the pushing depth of the cell 10 into the bristles is about 0 to 5 mm from the cell passing part and pushed so as to come into contact. Thus, the CVD foreign matter adhering to the back surface of the cell can be removed. Since the cell 10 is damaged when the pushing depth of the cell 10 into the bristles of the flat brush 49 exceeds 5 mm, it is desirable not to exceed 5 mm.

Also, it is desirable that one hair of the flat brush 49 has a length of about 50 μmΦ and 5 to 40 mm. Particularly desirable is 10 to 30 mm. If the length of the ciliary body exceeds 40 mm, it is difficult to obtain processing accuracy when cutting the hair tips. Also, as you continue to use it, the hair tips will bend and become wrinkled easily. In particular, in the case of a flat brush, it is difficult to correct wrinkles. Moreover, it will become easy to be damaged, if the length of a ciliary body is less than 5 mm.

Embodiment 3 FIG.
The manufacturing method of the photovoltaic cell concerning this invention, the structure of a photovoltaic cell, and its manufacturing process are demonstrated. The configuration of the solar battery cell will be described with reference to FIGS. 8 (a) to (c). FIG. 8A is a cross-sectional view for explaining the configuration of the solar battery cell 10 according to the embodiment of the present invention, and FIG. 8B is a top view of the solar battery cell 10 viewed from the light receiving surface side. 8 (c) is a bottom view of the solar battery cell 10 as viewed from the side opposite to the light receiving surface. FIG. 8A is a cross-sectional view in the XX direction of FIG. FIG. 9 is a flowchart showing a manufacturing process of the solar battery cell 10. In this solar cell 10, an n-type impurity diffusion layer 3 is formed by phosphorus diffusion as a second conductivity type semiconductor layer on the light-receiving surface side of a p-type single crystal silicon substrate as a substrate 2, and a semiconductor having a pn junction. A substrate 11 is configured. An antireflection film 4 made of a silicon nitride film (SiN film) is formed on the n-type impurity diffusion layer 3. In the present embodiment, after the formation of the antireflection film 4, prior to forming the electrodes on the light receiving surface side and the back surface side, a foreign matter removing step (FIG. 9: Step S40) using the rotating brush 37 is added. Features.

The substrate 2 is not limited to a p-type single crystal silicon substrate, and a p-type polycrystalline silicon substrate may be used.

Further, on the light receiving surface side surface of the semiconductor substrate 11 (n-type impurity diffusion layer 3), fine irregularities are formed as a texture structure. The micro unevenness increases the area for absorbing light from the outside on the light receiving surface, suppresses the reflectance on the light receiving surface, and has a structure for confining light. Further, on the light receiving surface side of the semiconductor substrate 11, a light receiving surface side electrode 12 including the surface silver grid electrode 6 and the surface silver bus electrode 5 is formed. As shown in FIG. 8B, the front silver bus electrode 5 is provided so as to be orthogonal to the front silver grid electrode 6, and is electrically connected to the n-type impurity diffusion layer 3 at the bottom surface portion. . The front silver bus electrode 5 and the front silver grid electrode 6 are made of a silver material.

On the other hand, a back surface electrode 7 made of an aluminum material is provided on the entire back surface (surface opposite to the light receiving surface) of the semiconductor substrate 11, and extends in the same direction as the front silver bus electrode 5 and made of a silver material. A back surface collecting electrode 8 is provided. The back electrode 7 and the back collecting electrode 8 constitute a back electrode 13 as the second electrode.

In solar cell 10 configured in this way, sunlight is applied to the pn junction surface (the junction surface between substrate 2 and n-type impurity diffusion layer 3) of semiconductor substrate 11 from the light-receiving surface side of solar cell 10. Then, holes and electrons are generated. Due to the electric field at the pn junction, the generated electrons move toward the n-type impurity diffusion layer 3, and the holes move toward the substrate 2. As a result, electrons are excessive in the n-type impurity diffusion layer 3 and holes are excessive in the substrate 2. As a result, a photovoltaic force is generated. This photovoltaic power is generated in the direction of biasing the pn junction in the forward direction, the light receiving surface side electrode 12 connected to the n-type impurity diffusion layer 3 becomes a negative pole, and the back surface side electrode 13 connected to the substrate 2 becomes a positive pole. Thus, a current flows through an external circuit (not shown).

Next, an example of a method for manufacturing the solar battery cell 10 will be described. FIG. 9 is a flowchart for explaining a manufacturing process of the solar battery cell 10. FIG. 10A to FIG. 10G are cross-sectional views for explaining the manufacturing process of the solar battery cell.

First, for example, a p-type single crystal silicon substrate is prepared as the substrate 2, and the p-type single crystal silicon substrate is cleaned using hydrogen fluoride, pure water, or the like. After that, fine irregularities are formed on the surface of the p-type single crystal silicon substrate to form a texture structure (pyramid structure) on the surface (FIG. 9: Step S10, FIG. 10 (a)). )). As the texture formation, for example, a p-type single crystal silicon substrate is etched with an aqueous alkali solution such as an aqueous sodium hydroxide solution (additives may be added in some cases).

Next, the p-type single crystal silicon substrate is put into a thermal oxidation furnace and heated in the presence of phosphorus oxychloride (POCl ₃ ) vapor to form phosphorus glass on the surface of the p-type single crystal silicon substrate. As a result, phosphorus is diffused into the p-type single crystal silicon substrate, the n-type impurity diffusion layer 3 is formed on the surface layer of the p-type single crystal silicon substrate, and a pn junction is formed (FIG. 9: Step S20, FIG. 10). (B)). Here, a phosphor glass layer mainly composed of glass on the surface immediately after the formation of the n-type impurity diffusion layer 3 and an n-type impurity diffusion layer 3 formed on the back surface of the p-type single crystal silicon substrate are hydrofluoric acid (HF). It is removed by wet etching with a mixed acid of / nitric acid (HNO ₃ ) / sulfuric acid (H ₂ SO ₄ ). Thus, a pn junction is formed by the substrate 2 made of p-type single crystal silicon as the first conductivity type layer and the n-type impurity diffusion layer 3 as the second conductivity type layer formed on the light receiving surface side of the substrate 2. The formed semiconductor substrate 11 is obtained (FIG. 10C).

Next, a SiN film is formed on the n-type impurity diffusion layer 3 as the antireflection film 4 by the plasma CVD method (FIG. 9: step S30, FIG. 10 (d)). The film thickness and refractive index of the antireflection film 4 are set to values that most suppress light reflection. Note that two or more layers having different refractive indexes may be laminated as the antireflection film 4. The antireflection film 4 may be formed by a different film forming method such as a sputtering method.

Thereafter, the surface of the antireflection film 4 is lightly rubbed by the foreign matter removing device using the rotating brush 37 shown in FIG. 1 to remove the foreign matter attached to the surface (FIG. 9: Step S40). This process is a feature of the present embodiment, and this process will be described in detail later.

Next, electrodes are formed by screen printing. First, the back side electrode 13 is created (before firing). That is, the aluminum paste 7a as the electrode material paste is applied to the shape of the back electrode 7 by screen printing on the back side of the p-type single crystal silicon substrate, and dried at about 100 ° C. to 300 ° C. Further, a silver paste 8a as an electrode material paste is applied to the shape of the back surface collecting electrode 8, and dried at about 100 ° C. to 300 ° C. (FIG. 9: Step S50, FIG. 10 (e)).

Next, the light receiving surface side (surface side) electrode 12 is prepared (before firing). That is, after applying the silver paste 12a to the shape of the front silver bus electrode 5 and the front silver grid electrode 6 on the antireflection film 4 which is the light receiving surface of the p-type single crystal silicon substrate as the substrate 2, by screen printing, The silver paste 12a is dried (FIG. 9: Step S60, FIG. 10 (f)).

Thereafter, the paste is baked at a temperature of about 700 ° C. to 900 ° C. for a time of several minutes to ten and several minutes. Thereby, the front silver bus electrode 5 and the front silver grid electrode 6 as the light receiving surface side electrode 12, and the back electrode 7 and the back current collecting electrode 8 as the back surface side electrode 13 are obtained (FIG. 9: Step S70, FIG. 10). (G)).

By performing the steps as described above, the solar battery cell 10 shown in FIGS. 8A to 8C can be manufactured. In addition, the order of arrangement of the paste, which is an electrode material, on the semiconductor substrate 11 may be switched between the light receiving surface side and the back surface side.

Next, the foreign matter removing step S40 in the method for manufacturing the solar cell according to the present embodiment will be described. 11 (a) to 11 (c) are enlarged cross-sectional views of the main part showing the foreign matter removing step S40 according to the present embodiment. In the formation process of the antireflection film (FIG. 9: Step S30), when the SiNOH film is formed using the plasma CVD method, foreign substances fall and adhere to the semiconductor substrate during the film formation. The following inconveniences may occur in the printing process. That is, when the electrode material paste is applied to the surface of the solar battery cell by screen printing, the electrode material paste may not be applied in a desired shape to a place where the foreign material is present. Furthermore, since the electrode material paste cannot be applied in a desired shape due to the clogging of foreign matter in the printing mask pattern, the electrode material paste may not be applied in the desired shape even in a solar battery cell without foreign matter adhesion. is there. When the electrode material paste cannot be applied in a desired shape as described above, the photoelectric conversion efficiency is lowered due to a decrease in curvature factor (F.F), and if the desired photoelectric conversion efficiency cannot be obtained, it becomes defective. The rate increases. In addition, when the printing mask that is clogged with foreign matter is replaced, the productivity decreases.

Therefore, in the present embodiment, as a foreign matter removing step (FIG. 9: step S40) after the antireflection film forming step, the foreign matter removing apparatus shown in FIG. The surface of the antireflection film is rubbed with the rotating brush 37 while air blowing.

Factors that improve the foreign matter removal rate by removing foreign matter using the rotating brush 37 will be described with reference to FIGS. 11 (a) to 11 (c). FIG. 11A shows an enlarged view of the vicinity of the surface of the semiconductor substrate 11 when the foreign particle 14 adheres before the antireflection film 4 is formed. This step corresponds to an enlarged view of the vicinity of the surface of the semiconductor substrate 11 during the step of forming the antireflection film 4 in FIG. Prior to the formation of the antireflection film 4, foreign particles 14 (or coarse particles) fall from the CVD apparatus to the n-type impurity diffusion layer 3 and adhere to the surface of the n-type impurity diffusion layer 3. After the foreign matter adheres, in the film formation step of the antireflection film 4, the antireflection film 4 is formed so as to surround the periphery of the foreign particle 14 as shown in FIG. A portion where the antireflection film 4 surrounds the foreign particle 14 as in the portion A in FIG. 11B has a low foreign matter removal rate in the water washing process. However, as shown in FIG. 11 (c), the foreign particles 14 are peeled off, including the antireflection film 4 that wraps around the foreign particles 14 like the A 'portion, by rubbing lightly using the rotating brush 37. To do.

By carrying out the step of rubbing with the rotating brush 37 in this way, the foreign particle 14 is easily peeled off from the surface of the semiconductor substrate 11, and the foreign matter removal rate is improved. In addition, in removing the antireflection film 4 that wraps around the foreign particle 14, a physical process of rubbing with the rotating brush 37 is used in the third embodiment, but a fluorine gas system (F ₂ , NF ₃ , ClF) is used. Chemical treatment such as dry etching treatment with plasma of ₃ ) may be used in combination.

When performing the brushing process, if the surface of the antireflection film 4 (silicon nitride) or the n-type impurity diffusion layer 3 (silicon) is scratched or the texture structure is destroyed, the photoelectric conversion efficiency is lowered. For this reason, the hair material constituting the rotating brush 37 must be made of silicon oxynitride or a material that is sufficiently softer than silicon. A soft material having a Mohs hardness of 3 or less is preferable. Examples thereof include nylon and polypropylene. In addition, when the diameter of the crust of the rotating brush is thin, the force to remove the foreign matter is weak, and if it is too thick, it is difficult to remove the foreign matter in the textured groove on the substrate surface, so that a desired foreign matter removal rate can be obtained. The diameter of the hair of the rotating brush is preferably 10 to 100 μm.

Furthermore, when the surface of the antireflection film 4 is brushed with the rotating brush 37 to which the foreign particle 14 is attached by the brushing process, a desired foreign matter removal rate may not be obtained due to the reattachment. Alternatively, the surface of the antireflection film 4 (silicon nitride) or the n-type impurity diffusion layer 3 (silicon) may be damaged or the texture structure may be destroyed. These all cause a decrease in photoelectric conversion efficiency.

In the present embodiment, as shown in FIG. 1, a third dust collector 43 that sucks the foreign particle 14 or coarse particle 14 </ b> G attached to the brush is installed in the removal mechanism including the rotary brush 37, and the rotary brush 37. Remove foreign material adhering to the surface. Thereby, a desired foreign matter removal rate can be stably obtained, and it is possible to prevent the silicon nitride or silicon from being damaged or the texture structure from being destroyed.

Embodiment 4 FIG.
FIG. 12 is a cross-sectional view of the foreign matter removing apparatus using the rotating brush device according to the fourth embodiment of the present invention. This foreign matter removing apparatus is on the side where the tip of the rotating brush 37 descends, that is, after contacting the cell 10. The rotating plate 40S which contacts is provided at the position rotated by 270 degrees. And this wiping board 40S is covered with the dust collection nozzle 50 installed apart from the rotating brush 37, and exhausts the circumference | surroundings of the wiping board 40S. The space between the wiping plate 40S and the dust collection nozzle 50 is 6 mm or less, the exhaust speed of the space is 5 m / sec or more, and the protruding amount X of the wiping plate 40S from the dust collection nozzle 50 is within 10 mm. And the dust collection nozzle 50 is connected to the 4th dust collector 51, and exhausts the circumference | surroundings of the wiping board 40S. Tip of the payment plate 40S is disposed to come to the position of the axial center distance S _A of the rotary brush 37. Thus the distance between the tip of the payment plate 40S and the rotary brush 37 has a value obtained by subtracting the distance S _A from the radius R of the rotary brush 37. The payment plate 40S is supported by support (not shown) at a distance S _C from the conveyor belt 20. The payment plate height of 40S height of the axis of the rotary brush 37 that is located at a distance S _B from the conveying belt 20, slightly pay plate 40S is low. The amount that the brush tip pushes into the cell is the same as the amount that the brush tip pushes into the wiper, and is preferably 1 mm or less. The distance S _B and the distance S _C are desirably the same value, and even if there is a difference, it is desirable that the distance S _B and the distance S _C be 2 mm or less.

This foreign matter removing apparatus is mounted on a conveyor belt 20 that conveys solar cells after forming a functional film by the CVD method, as in the first to third embodiments. This foreign matter removing device is a device for removing foreign fine particles 14 adhering to the surface of a cell 10 constituting a solar battery, and makes the foreign matter come into contact with the transport belt 20 as a transport section and the cell 10 on the transport belt 20. The rotary brush 37 to be removed, the wiper plate 40S that comes into contact with the rotary brush 37 and wipes off the foreign matter attached to the rotary brush 37, and a cleaning unit are included. The conveyor belt 20 holds the cell 10 with a smooth surface and conveys it in the direction indicated by the arrow A. The rotating brush 37 is made of a high-molecular fiber made of a large number of non-metallic hairs and having a hardness lower than that of silicon, which is a substrate for a solar battery constituting a solar battery cell.

According to this foreign matter removing device, the foreign matter fine particles 14 are wiped off by the rotating brush 37 and most of them are blown off or collected by the fourth dust collector 51. Some of them are adsorbed on the wiping plate 40S, but are removed by the dust collecting nozzle 50. Therefore, even when a large amount of foreign particles 14 are generated, they fall in a large amount from the wiping plate 40S to the brush bristle gap. It is possible to avoid a situation in which the brush is soiled or a large amount of foreign particle 14 is reattached to the cell 10.

As shown in FIG. 12, the foreign particle 14 on the cell 10 adheres to the tip of the rotating brush 37 and is then adsorbed to the wiping plate 40S. In this wiping plate 40S, the tip of the wiping plate 40S slightly protrudes from the dust collecting nozzle 50 in a “tongue shape”, and the dust collecting nozzle 50 covering the wiping plate 40S exhausts a narrow gap at an air flow velocity V, and the foreign particle 14 Is collected and exhausted by the fourth dust collector 51 to be recovered.

If the clearance d = 6 mm or less and the exhaust velocity V = 5 m / sec or more, the foreign particle 14 having a size of 0.5 mm or less is all the fourth if the distance X from the wiper plate 40S to the dust collection nozzle 50 is within 10 mm. The exhaust gas can be collected up to the dust collector 51. If the gap d exceeds 6 mm, it is difficult to apply a sufficient exhaust flow to the wiping plate 40S, and exhaust recovery becomes difficult. If the exhaust speed is less than V = 5 m / sec, the foreign particle 14 remains attached to the inner wall of the dust collection nozzle 50, making it difficult to collect the foreign particle 14 by exhaust. Desirably, by realizing exhaust at an exhaust speed of about 10 to 30 m / sec, foreign particles 14 can be reliably recovered by exhaust.

In Embodiment 4 of the present invention, by providing the conveyor belt 20 of the solar battery cell and the rotating brush 37 in contact with the solar battery cell, foreign matter adhering to the surface of the solar battery cell can be removed. Further, by providing the wiper plate 40S that comes into contact with the bristles of the rotating brush 37, foreign substances attached to the bristles of the rotating brush 37 can be removed, so that the solar cells are damaged by the foreign substances attached to the rotating brush 37. It can prevent that the foreign material adhering to the rotating brush 37 adheres again to a photovoltaic cell. Further, by surrounding the wiping plate 40S with the dust collecting nozzle 50 and exhausting it, the foreign particle 14 is prevented from adsorbing to the wiping plate 40S, and the foreign particle 14 is reattached to the rotating brush 37 from the wiping plate 40S. Can be prevented.

In addition, as shown in FIG. 12, the wiping plate 40S contacts on the side where the tip of the rotary brush 37 having the radius R descends. If the rotation direction is counterclockwise as shown in FIG. 12, the tip of the rotating brush 37 descends in the left half of the rotating brush 37, so that the wiper plate 40 </ b> S is installed in the left half. Thereby, the foreign particle 14 that has been wiped off from the bristles of the rotating brush 37 floats above the wiping plate 40S. Thereby, even if the suction force of the dust collection nozzle 50 is temporarily reduced, foreign matter can be received on the wiping plate 40S, so that there is an effect of preventing the foreign matter from falling onto the cell 10. In the above embodiment, no air blow is performed, but also in this embodiment, the tip of the rotating brush 37 is cleaned by performing an air blow (not shown) at a speed larger than the floating speed of the foreign matter to be removed. May be.

Embodiment 5 FIG.
In the fourth embodiment shown in FIG. 12, there is one gap on the upper side of the wiper plate 40S and the dust collecting nozzle 50, and there is a concern that the foreign fine particles 14 adhere to the back side of the wiper plate 40S. In this Embodiment, as shown in FIG. 13, the clearance gap is provided above and below the payment plate 40S. In this example, the foreign particles 14 adhering to the tips of the rotating brush 37 and the wiper plate 40S can be exhausted and recovered more efficiently. Others are the same as those of the fourth embodiment, and the description is omitted here.

Embodiment 6 FIG.
In the foreign matter removing apparatus of

Embodiments

4 and 5 shown in FIGS. 12 and 13, dust collection is performed only by the wiping plate 40S and the dust collection nozzle 50, but it is covered by the cover 44 as in the first embodiment. The foreign matter to be collected may not be scattered outside. As the sixth embodiment, an example using both the dust collection nozzle 50 and the cover 44 will be described as shown in FIG. Others are the same as those in the first embodiment and the fourth embodiment, and the description is omitted here. Due to the relationship with the cover 44, the wiping plate 40 r is provided at a position where the rotating brush 37 rotates 90 degrees after the foreign particles 14 on the cell 10 are removed. As in the fourth embodiment, the dust collection nozzle 50 covers the periphery of the wiping plate 40 r and is connected to the fourth dust collector 51. Also in the present embodiment, the AA cross section is as shown in FIG. 2 as in the first embodiment, but the description is omitted here.

As in the first embodiment shown in FIG. 1, a state where CVD foreign matters such as coarse foreign particles 14G and foreign fine particles 14 are on the cell 10 is shown. The CVD foreign matter includes foreign matter coarse particles 14G that can be suspended and removed by an air flow 35N flowing into the cover through a gap between the air blow 35 and the cover 44, and foreign matter fine particles 14 that can be removed by the rotating brush 37. When the relationship between the size of CVD foreign particles and the floating speed is calculated, if the antireflection film is a SiNOH film, the floating speed is 0.3 m / sec if it is a spherical particle of 50 μm size, which is a problem in the grid printing process. In the 10 μm size, the floating speed is 0.01 m / sec. The floating speed varies exponentially with the particle size. Large coarse particles with a size of 0.1 mm soar with an air blow of 1 to 2 m / sec.

Also here, first, in order to avoid deterioration of the rotating brush 37 due to the foreign particle coarse particles 14G, air of 2 m / sec or more is blown by the air blow 35 and collected in the first dust collector 36 on the upstream side.

Also in this embodiment, the foreign matter is efficiently removed and a highly reliable solar cell can be obtained. However, in this embodiment, the wiping plate 40r is provided at a position where the rotating brush 37 is rotated 90 degrees after the foreign particle 14 on the cell 10 is removed. In the present embodiment, immediately after the foreign particles 14 on the cell 10 are removed, the rotating brush 37 peels off the foreign particles 14 by the wiping plate 40r and is efficiently recovered by the dust collection nozzle 50. The flying of the foreign particle 14 can be suppressed. A second wiping plate may be provided at a position facing the wiping plate 40r with respect to the axial center of the rotating brush 37 to further clean the rotating brush 37.

In the above-described embodiment, the diffusion type solar cell in which the n-type impurity is diffused in the p-type single crystal silicon substrate to form the pn junction has been described. However, the n-type single crystal silicon substrate, the n-type polycrystalline silicon substrate, etc. It can be applied to other optical elements such as thin film EL elements as well as thin film solar cells in which a pn junction is formed by forming a p-type amorphous silicon layer, a p-type polycrystalline silicon layer, etc. on the surface of a silicon substrate. .

The antireflection film is not limited to a silicon oxynitride film, but is a silicon oxynitride film, a silicon nitride film, or a multilayer film in which a silicon oxynitride film, a silicon nitride film, etc. are laminated. This is particularly effective for an inorganic film formed by vapor deposition in a chamber such as an apparatus.

As described above, the foreign matter removing apparatus and the solar cell manufacturing method using the same according to the present invention are useful for removing foreign matters without damaging the surface, and in particular, solar cells after formation of a CVD film. It is suitable for removing foreign substances on the substrate surface.

2 (p-type single crystal silicon) substrate, 3 n-type impurity diffusion layer, 4 antireflection film, 5 surface silver bus electrode, 6 surface silver grid electrode, 7 back electrode, 7a aluminum paste, 8 back current collecting electrode, 8a silver Paste, 10 cells, 11 semiconductor substrate, 12 light receiving surface side electrode, 12a silver paste, 13 back surface side electrode, 14G foreign material coarse particles, 14 foreign material fine particles, 20 transport belt, 21 turntable, 22 stage plate, 35 air blow, 35N Large airflow, 36 1st dust collector, 37 rotating brush, 38 receiving roller, 39 rotating shaft, 40, 40S, 40P, 40r wiper plate, 41 2nd dust collector, 42 air blow, 43 3rd dust collector, 44 cover, 45 Rotating Brush (Fuzz Disorder), 46 Cut Blade, 49 Flat Brush, 50 Dust Collection Le, 51 fourth dust collector.

Claims

A foreign matter removing device for removing foreign matter adhering to the surface of a solar battery cell,
A transport unit that transports the solar battery cell while holding it on a smooth surface;
A brush composed of a large number of non-metallic hairs, which contacts the solar cells on the transport unit to remove foreign substances,
A wiping plate that contacts the brush and wipes off foreign matter adhering to the brush;
Foreign matter removing device having
The foreign matter removing apparatus according to claim 1, wherein the brush is a rotating brush.
The foreign matter removing apparatus according to claim 1 or 2, further comprising a dust collection nozzle that surrounds the wiping plate and is spaced apart from the brush and exhausts around the wiping plate.
4. The foreign matter removing apparatus according to claim 3, wherein the wiper plate contacts on the side where the tip of the rotating brush descends.
The space between the wiping plate and the dust collecting nozzle is 6 mm or less, the exhaust speed of the space is 5 m / sec or more, and the protruding amount of the wiping plate from the dust collecting nozzle is within 10 mm. Item 5. A foreign matter removing apparatus according to Item 4.
The foreign matter removing apparatus according to any one of claims 1 to 5, wherein the brush has an outer diameter of the ciliary body of 0.2 mm or less.
The foreign matter removing apparatus according to any one of claims 1 to 6, wherein the brush has a length of the ciliary body of 5 mm to 40 mm.
The foreign matter removing apparatus according to any one of claims 1 to 7, wherein the brush has a cross-sectional density of 20% to 80% of the ciliary body.
The foreign matter removing apparatus according to any one of claims 1 to 8, wherein the brush has a metal content of less than 1000 ppm.
When the brush has a protruding part that protrudes outward from the cell surface of the solar battery cell, a receiving roller is provided at a position facing the protruding part to synchronize the cell conveyance system, the receiving roller, and the brush. The foreign matter removing apparatus according to claim 1, further comprising a synchronization mechanism.
The foreign matter removing apparatus according to any one of claims 1 to 10, wherein a brush peripheral speed of the brush and a relative speed of a cell surface of the solar battery cell are 600 mm / sec or less.
The foreign matter removing apparatus according to any one of claims 1 to 11, wherein an amount of pushing the brush into a cell surface of the solar battery cell is 0.001 mm or more and 3 mm or less.
When the outer diameter dimensional accuracy of the brush is 0.01 mm or less and the amount of pushing the brush into the cell surface has a height accuracy of 0.001 mm to 0.1 mm, the brush peripheral speed and the cell surface relative speed are 2000 mm. The foreign matter removing apparatus according to any one of claims 1 to 12, wherein the foreign matter removing apparatus is set to / sec or less.
The foreign matter removing apparatus according to claim 1, wherein the brush is a linear brush.
15. The foreign matter removing apparatus according to claim 14, wherein an amount of pushing the brush into a cell surface of the solar battery cell is 0 to 5 mm.
The foreign matter removing apparatus according to any one of claims 1 to 15, wherein the brush is made of a polymer fiber having a hardness lower than that of a solar battery substrate constituting the solar battery cell.
Each function of one printing machine in the automatic conveyance printing line has a cell insertion positioning position, a cell surface foreign matter cleaning position, an electrode printing position, and a cell inspection discharge position in the order of processing. The foreign matter removal apparatus according to claim 1, wherein the foreign matter removal is performed by sweeping the cell surface by the method.
The foreign matter according to any one of claims 1 to 17, further comprising a cleaning unit that performs air blowing at a tip of the brush at a speed larger than a floating speed of the foreign matter to be removed. Removal device.
Preparing a first conductive type crystalline semiconductor substrate having a second conductive type semiconductor layer on the first surface side having a texture structure;
Forming an antireflection film on the semiconductor layer of the second conductivity type;
A brush made of a large number of non-metallic hairs, in contact with the crystalline semiconductor substrate on which the anti-reflection film is formed on the transport section, contacts the brush to remove foreign matter, contacts the brush, Using a foreign material removal device equipped with a wiper plate to remove the adhered foreign material,
The step of removing the foreign matter by brushing with the brush while the antireflection film surface is in contact with the brush with the wiping plate and the foreign matter attached to the brush is wiped off;
Forming a light receiving surface side electrode electrically connected to the semiconductor layer of the second conductivity type on the antireflection film.
The foreign matter removing apparatus further includes a cleaning unit that performs air blowing at a tip larger than the floating speed of the foreign matter to be removed at the tip of the brush for cleaning.
The step of removing the foreign matter includes
21. The sun according to claim 19, wherein the antireflection film surface is a step of removing foreign matter by brushing with a brush while performing air blowing at a speed larger than a floating speed of the foreign matter to be removed. Battery manufacturing method.