JP5395592B2 - Electrode forming apparatus and electrode forming method - Google Patents

Description

  The present invention relates to an apparatus and method for forming an electrode on a substrate by discharging a coating solution containing an electrode material from a nozzle, and more particularly to an apparatus and method for forming an electrode on a solar cell substrate.

  As a technique for forming a predetermined pattern on a substrate, there is a method of drawing a pattern on a substrate by moving a nozzle for discharging a coating liquid containing a pattern material relative to the substrate. Here, when a pattern that intersects with each other on the substrate is formed by coating, the height of the pattern may be higher than other portions due to the coating liquid being applied twice at the pattern intersection. In order to avoid this problem, for example, in the technique described in Patent Document 1 previously disclosed by the applicant of the present application, when forming a rib pattern intersecting on a substrate, After the portion intersecting with the rib pattern formed in step (2) is removed, the subsequent rib pattern is formed.

  The above technique is a technique for forming a rib pattern on a glass substrate for a plasma display device, and it is conceivable to form an electrode on, for example, a solar cell substrate. In an electrode of a solar cell, for example, as described in Patent Document 2, a large number of thin electrodes also referred to as finger electrodes and a wide electrode also referred to as a bus electrode that crosses these electrodes are combined.

Japanese Patent Laying-Open No. 2008-098001 (for example, FIG. 9) Japanese Patent Laying-Open No. 2005-353851 (for example, FIG. 1)

  However, the technique described in Patent Document 1 described above requires a large number of processes, such as the need to partially remove the pattern once formed by coating, and the electrical conduction between the intersecting patterns is not necessarily guaranteed. Problems remain in applying to electrode formation on battery substrates. Patent Document 2 does not mention the height at the intersection between the finger electrode and the bus electrode.

  Thus, in the technique of forming electrodes that cross each other on a substrate by nozzle coating, a technique for forming electrodes in a simple process while suppressing the swell of the electrodes at the intersection has not been established.

  The present invention has been made in view of the above problems, and in a method and apparatus for forming an electrode on a substrate by discharging a coating liquid containing an electrode material from a nozzle, the electrode is swelled at an intersection in a simple process. It aims at providing the technique which can be suppressed.

In a first aspect of the electrode forming apparatus according to the present invention, in order to achieve the above object, a coating liquid containing an electrode material is discharged onto the coated surface while moving relative to the coated surface of the substrate in the first direction. Thus, the first electrode nozzle for forming the first electrode on the coated surface and the coated surface on which the first electrode formed by curing the coating solution is different from the first direction. a coating solution containing an electrode material while relatively moving in two directions by discharging the coated surface, and a second electrode for the nozzle that forms the second electrode intersecting the first electrode to the coated surface, the first A height detecting means for detecting the height of the top surface of one electrode from the coated surface, and a distance between the coated surface and the second electrode nozzle is controlled based on a detection result of the height detecting means. control and means, prior to the second electrode for the nozzle before Symbol substrate When passing through the position facing the first electrode, said control means in close proximity facing said top surface of said first electrode a discharge port of the nozzle for the second electrode, thereby clogging the discharge ports by the top surface It is characterized by that.

  In the invention configured in this way, when the second electrode nozzle that moves relative to the substrate passes through the position facing the first electrode, the ejection port is in close proximity to the top surface of the first electrode. Go through position. That is, at this facing position, the discharge port and the top surface of the first electrode are in a state of facing each other by a minute distance. For this reason, since the discharge port is blocked by the top surface of the first electrode and the discharge of the coating liquid is suppressed, it is prevented that the coating liquid is further applied on the first electrode. .

  Therefore, the increase in the height of the electrode at the intersection of the first electrode and the second electrode is suppressed without increasing the number of steps as compared with the case where the coating liquid is applied by simply scanning the nozzle in two directions. Can do. In addition, since the second electrode nozzle passes through the position facing the first electrode in a state where the coating liquid can be discharged, the conduction between the first electrode formed first and the second electrode formed later is ensured. Can be obtained. As described above, according to the present invention, it is possible to form electrodes that cross each other on the substrate in a simple process and while suppressing the swelling of the electrodes at the intersections.

  About the discharge port of the nozzle for 2nd electrodes, it is desirable to pass as close as possible in the range which does not contact the top face of the 1st electrode. In particular, if the passage position of the nozzle for the second electrode is determined so that the distance from the top surface of the first electrode is substantially zero, the coating liquid is hardly applied on the first electrode, and the first electrode The rise of the electrode at the intersection with the second electrode can be made substantially zero.

  Here, the distance between the surface to be coated and the nozzle for the second electrode can be changed, and control means for controlling the distance may be provided. By doing so, the position of the discharge port of the second electrode nozzle can be set according to the height of the first electrode, and the rise at the intersection of the first electrode and the second electrode can be further suppressed. Can do.

Moreover, the 2nd aspect of the electrode forming apparatus concerning this invention is with respect to the said to-be-coated surface of the board | substrate in which the 1st electrode extended along a 1st direction was formed in the to-be-coated surface in order to achieve the said objective. A second electrode that crosses the first electrode is formed on the surface to be coated by discharging a coating liquid containing an electrode material to the surface to be coated while relatively moving in a second direction different from the first direction. An electrode nozzle, a height detecting means for detecting a height of the top surface of the first electrode from the coated surface, and the coated surface and the second electrode based on a detection result of the height detecting means And controlling the interval with the nozzle for use when the second electrode nozzle passes through the position facing the first electrode on the substrate, the discharge port of the second electrode nozzle is used as the top surface of the first electrode. by closely opposed to, and control means Ru occlude said discharge port by said top surface It is characterized in that it comprises.

In the invention thus configured, the second electrode nozzle is opposed to the first electrode in a state where the discharge port is close to and opposed to the top surface of the first electrode with respect to the substrate on which the first electrode is formed. Since the discharge port is controlled so as to be closed by the top surface , the electrodes that cross each other are formed on the substrate in a simple process and while suppressing the swell of the electrodes at the intersection, as in the above-described invention. Can be formed.

In these inventions, the height from the coated surface of the top surface of the first electrode is detected, that controls the distance between the coated surface and the second electrode for the nozzle on the basis of the detection result of it. In this way, since the distance between the coated surface and the second electrode nozzle is set based on the height of the first electrode actually formed, the electrode at the intersection of the first electrode and the second electrode Can be more reliably suppressed.

  The opening surface of the discharge port of the second electrode nozzle may be substantially parallel to the surface to be coated. In this way, the discharge port is almost completely blocked by the top surface of the first electrode to restrict the discharge of the coating liquid, and even if there is a coating liquid discharged onto the first electrode, Since it is scraped off by the end portion, almost no coating liquid remains on the first electrode after passing through the nozzle, and the swell of the electrode at the intersection can be prevented.

  Further, the opening length of the discharge port along the second direction, that is, the moving direction of the second electrode nozzle, may be made smaller than the width of the first electrode along the second direction. If it does in this way, when the nozzle for 2nd electrodes is located in the position facing a 1st electrode, the whole surface of the opening surface of a discharge outlet will oppose the top surface of a 1st electrode. Therefore, the supply of the coating liquid to the first electrode can be minimized, and the swell of the electrode at the intersection can be more reliably suppressed. In this sense, when electrodes having different widths are crossed, it is preferable to form the wider one first as the first electrode and the narrower one later as the second electrode.

  In these inventions, the second electrode nozzle is configured to discharge a coating liquid containing a photocurable resin, and light that irradiates the coating liquid applied to the coated surface from the second electrode nozzle. You may make it provide an irradiation means. In the invention configured as described above, since the coating liquid can be cured in a short time, it is possible to form a so-called high aspect ratio electrode having a narrow width and a high height. Therefore, the invention configured in this way can be suitably applied to the formation of solar cell electrodes that are required to have low electrical resistance and low shielding of incident light.

In order to achieve the above object, the electrode manufacturing method according to the present invention includes a first step of forming a first electrode extending along a first direction on the surface of the substrate, and the first step formed in the first step . A detection step of detecting the height of the top surface of one electrode from the substrate surface, and a nozzle for discharging a coating liquid containing an electrode material to the surface of the substrate on which the first electrode is formed, in the first direction A second step of forming a second electrode that intersects with the first electrode by relatively moving in different second directions, and in the second step , based on a detection result in the detection step, By controlling the distance from the nozzle for the second electrode so that the nozzle passes through the position facing the first electrode on the substrate, the discharge port of the nozzle is brought close to the top surface of the first electrode. while by passing, closes the discharge port by the top surface So it is characterized in Rukoto.

  In the invention configured as described above, similarly to the above-described invention of the electrode forming apparatus, it is possible to prevent the coating liquid from being applied to the first electrode, and the first electrode and the second electrode are connected to each other. It is possible to form an electrode with few swells at a crossing point with a simple process.

  In this invention, the detection process which detects the height from the substrate surface of the 1st electrode top surface formed in the 1st process is further provided, and in the 2nd process, based on the detection result in the detection process, the nozzle and the substrate surface The interval may be controlled. In this way, since the distance between the surface to be coated and the nozzle is set based on the height of the first electrode actually formed, the swell of the electrode at the intersection of the first electrode and the second electrode is further increased. It can be surely suppressed.

  In the second step, the opening surface of the nozzle outlet may be substantially parallel to the substrate surface. In this way, the coating liquid discharged onto the first electrode is scraped off by the end of the discharge port, so that almost no coating liquid remains on the first electrode after passing through the nozzle, and the electrode rises at the intersection. Can be prevented.

  In addition, it is preferable that the number of second electrodes formed is greater than the number of first electrodes formed. In other words, the number of electrodes to be formed later is preferably larger than the number of electrodes to be formed first. This is because forming a small number of electrodes first reduces the number of times that an electrode to be formed later crosses the previous electrode, thereby facilitating control. In this sense, when the number of two types of electrodes to be intersected is different, it is preferable to form the smaller number first as the first electrode.

  Similarly, the width of the second electrode along the first direction is preferably smaller than the width of the first electrode along the second direction. That is, the width of the electrode formed later is preferably smaller than the width of the electrode formed first. This is because it is easier to control the formation of the narrow electrode according to the wide formed electrode than to control the formation of the wide electrode according to the narrow formed electrode. In this sense, when the widths of the two types of electrodes to be intersected are different from each other, it is preferable to form the wider one first as the first electrode.

  Further, the first electrode and the second electrode may be formed at substantially the same height. In this invention, since the swell at the intersection of the first electrode and the second electrode is suppressed, if the first electrode and the second electrode are made substantially the same height, the entire electrode including those intersections is made almost the same height. Can be formed.

  According to the electrode forming apparatus and the electrode forming method according to the present invention, the second electrode can be formed while preventing the coating liquid from being further superimposed on the previously formed first electrode. The swell of the electrode at the intersection of the two can be suppressed.

It is a figure showing one embodiment of an electrode formation device concerning this invention. It is an enlarged view which shows the structure of a head part in detail. It is a figure which shows typically the mode of discharge of the coating liquid from a head part. It is a figure which shows an example of the solar cell module manufactured with this apparatus. It is a flowchart which shows the manufacturing method of the solar cell module by this electrode formation apparatus. It is a figure which shows the example of a scanning profile.

  FIG. 1 is a view showing an embodiment of an electrode forming apparatus according to the present invention. The electrode forming apparatus 1 forms a conductive electrode wiring on a substrate W such as a single crystal silicon wafer having a photoelectric conversion layer formed on the surface thereof, for example, and manufactures a photoelectric conversion device used as a solar cell, for example. Device. The apparatus 1 can be suitably used for an application in which a collecting electrode is formed on a light incident surface of a photoelectric conversion device, for example.

  In this electrode forming apparatus 1, a stage moving mechanism 2 is provided on a base 11, and a stage 3 that holds a substrate W can be moved in the XY plane shown in FIG. 1 by the stage moving mechanism 2. Two sets of frames 121 and 122 are fixed to the base 11 so as to straddle the stage 3, and the first head portion 5 is attached to the frame 121, and the second head portion 7 is attached to the frame 122. The second head unit 7 is spaced apart from the first head unit 5 in the (+ X) direction, and the distance between both is set wider than the length of the substrate W in the X direction.

  The stage moving mechanism 2 includes an X direction moving mechanism 21 that moves the stage 3 in the X direction from the lower stage, a Y direction moving mechanism 22 that moves the stage 3 in the Y direction, and a θ rotation mechanism 23 that rotates about an axis that faces the Z direction. Have. The X-direction moving mechanism 21 has a structure in which a ball screw 212 is connected to a motor 211 and a nut 213 fixed to the Y-direction moving mechanism 22 is attached to the ball screw 212. When the guide rail 214 is fixed above the ball screw 212 and the motor 211 rotates, the Y-direction moving mechanism 22 moves smoothly along the guide rail 214 in the X direction along with the nut 213.

  The Y-direction moving mechanism 22 also has a motor 221, a ball screw mechanism, and a guide rail 224. When the motor 221 rotates, the θ-rotation mechanism 23 moves in the Y direction along the guide rail 224 by the ball screw mechanism. The θ rotation mechanism 23 rotates the stage 3 about the axis facing the Z direction by the motor 231. With the above configuration, the relative movement direction and direction of the first and second head portions 5 and 7 with respect to the substrate W can be changed. Each motor of the stage moving mechanism 2 is controlled by the control unit 6.

  Further, a stage elevating mechanism 24 is provided between the θ rotation mechanism 23 and the stage 3. The stage elevating mechanism 24 elevates the stage 3 in accordance with a control command from the control unit 6 and positions the substrate W at a specified height (Z direction position). As the stage elevating mechanism 24, for example, a mechanism using an actuator such as a solenoid or a piezoelectric element, a mechanism using a gear, a mechanism using a wedge meshing, or the like can be used.

  The first head unit 5 includes a discharge nozzle unit 52 that discharges a liquid coating liquid onto the substrate W on the lower surface of the base 51, and a light irradiation unit 53 that irradiates UV light (ultraviolet light) toward the substrate W. A supply pipe 522 is attached to the discharge nozzle portion 52. The supply pipe 522 is connected to a tank 525 that stores a coating liquid containing an electrode material via a control valve 524. Nitrogen gas is introduced into the tank 525 via a regulator 526 from a nitrogen gas (N2) supply source (not shown), and the coating liquid in the tank 525 is pressurized to a constant pressure. When the control unit 6 controls the opening and closing of the control valve 524, ON / OFF of the coating liquid discharge from the discharge nozzle portion 52 is controlled.

  The light irradiation unit 53 is connected to a light source unit 532 that generates ultraviolet rays via an optical fiber 531. Although not shown, the light source unit 532 has a shutter that can be freely opened and closed at its light emitting portion, and the on / off of the emitted light and the amount of light can be controlled by the opening and closing and the opening degree. The light source unit 532 is controlled by the control unit 6.

  A height detection sensor 54 is provided on the opposite side of the discharge nozzle portion 52 with the light irradiation portion 53 interposed therebetween. For example, the height detection sensor 54 emits light or ultrasonic waves downward and detects reflected light or ultrasonic waves to detect the height of the upper surface of the substrate W and the substrate W of the structure formed on the substrate W. Detect height from top surface. The output signal of the height detection sensor 54 is input to the control unit 6.

  Similarly, the second head portion 7 is provided with a base 72, a discharge nozzle portion 72, and a light irradiation portion 73, and a supply pipe 724, a control valve 724, a tank 725, a regulator 726, and the like are connected to the discharge nozzle portion 72. ing. An optical fiber 731 and a light source unit 732 are connected to the light irradiation unit 73. The functions of these components are the same as those of the corresponding components provided around the first head unit 5. The second head 7 is not provided with a height detection sensor.

  FIG. 2 is an enlarged view showing the configuration of the head portion in more detail. More specifically, FIG. 2A is a view showing the vicinity of the tip of the discharge nozzle portion 52 when the first head portion 5 is viewed from below, and FIG. 2B is a view of the second head portion 7 viewed from below. It is a figure which shows the discharge nozzle part 72 tip vicinity at the time. The discharge nozzle portion 52 has a structure in which a cylindrical tip nozzle 521 having a discharge port 521a communicated with the cavity is protruded from a nozzle base 520 having a cylindrical cavity inside. The coating liquid transported from the tank 525 via the supply pipe 522 is discharged toward the substrate W from the discharge port 521a at the lower end of the tip nozzle 521. As shown in FIGS. 1 and 2A, the tip nozzle 521 extends from the nozzle base 520 in the (−Z) direction and the (+ X) direction.

  In addition, the light irradiation unit 53 has the same size in the Y direction as the nozzle base 520 in order to irradiate the entire coating liquid discharged from the discharge port 521a, and its lower end condenses light. Lens 531.

  As shown in FIG. 2B, the second head portion 7 is similarly provided with a nozzle base 720 and a tip nozzle 721, but is different from the first head portion 5 in the following points. That is, in the second head unit 7, a plurality of tip nozzles 721 having smaller discharge ports 721a are provided at equal intervals in the Y direction (four in this example, but not limited thereto). The tip nozzle 721 extends from the nozzle base 520 directly below, that is, in the (−Z) direction. In addition, the light irradiation part 73 provided with the lens 731 at the lower end is similar to the light irradiation part 53 of the first head part 5 so that the coating liquid discharged from each tip nozzle 721 is uniformly irradiated with light. Widely formed.

  The material of the tip nozzles 521 and 721 is not particularly limited. For example, silicon or zirconia crystals can be used from the viewpoint that contaminants are not mixed into the discharge liquid and fine processing can be performed. If the tip nozzle is detachably attached to the nozzle base, for example, if any of the discharge ports is clogged or damaged by the coating liquid, only the tip nozzle needs to be replaced. It is advantageous in terms of the running cost of the apparatus as compared with replacing the whole.

  FIG. 3 is a diagram schematically showing how the coating liquid is discharged from the head portion. More specifically, FIG. 3A is a diagram showing a state of discharge of the coating liquid from the first head unit 5, and FIG. 3B is a state of discharge of the coating liquid from the second head unit 7. FIG. As will be described later, in this embodiment, the coating liquid is discharged from the discharge port 521a of the tip nozzle 521 while the substrate W placed on the stage 3 is moved in the X direction by the stage moving mechanism 2. Accordingly, the coating liquid A1 discharged onto the substrate W moves along with the substrate W in the X direction (rightward in the figure). In terms of scanning movement with respect to the substrate W, it is equivalent even if the substrate W is fixed and the first head unit 5 is moved, but various pipes are connected to the first head unit 5, and the nozzle It is preferable to move the substrate W while fixing the first head unit 5 from the viewpoint of suppressing fluctuations in the discharge amount due to vibration.

  A light irradiation unit 53 is provided on the downstream side of the discharge nozzle unit 52 in the substrate movement direction, and irradiates the coating liquid A1 applied to the substrate W with light L1 (for example, ultraviolet rays). At the light irradiation position where the light L1 is irradiated onto the substrate W, if the coating liquid contains a photocurable resin, curing starts upon receiving light irradiation from the light irradiation unit 53. In this way, a photocurable resin is added to a coating solution containing an electrode material, and the coating solution immediately after coating is irradiated with light to be cured, thereby forming a high aspect ratio electrode having a narrow width and a high height. be able to.

  As described above and as shown in FIG. 3A, since the tip nozzle 521 extends from the nozzle base 520 in the (−Z) direction and the (+ X) direction, the plane P1 including the opening surface of the discharge port 521a. The normal vector V1 has a component toward the substrate moving direction. By opening the discharge port 521a in this way, it is possible to apply a high-viscosity coating liquid to the substrate W without staying around the discharge port 521a, and to irradiate the coating liquid immediately after coating with light. it can. The direction of the normal vector V1 is preferably 30 degrees or more and less than 90 degrees with respect to the vertically downward direction.

  On the other hand, as shown in FIG. 3B, in the second head unit 7, the tip nozzle 721 extends downward (−Z direction) from the nozzle base 720. Accordingly, the plane P2 including the opening surface of the discharge port 721a is substantially parallel to the upper surface of the substrate W, and its normal vector V2 is also downward. A light irradiation unit 53 is provided downstream of the discharge nozzle unit 52 in the substrate movement direction, and irradiates the coating liquid A2 discharged from the tip nozzle 721 and applied to the substrate W with the light L2. In this way, the apparatus 1 can form a predetermined pattern on the substrate W.

  FIG. 4 is a diagram showing an example of a solar cell module manufactured by this apparatus. In this solar cell module M, finger electrodes F and bus electrodes B are provided on the upper surface (light incident surface) of a substrate W provided with a photoelectric conversion layer. The finger electrodes F are electrodes that are narrow in width so as not to block incident light and that have a large thickness so as to have a low resistance, and a large number are formed in parallel to each other. On the other hand, one or a plurality of bus electrodes B are formed so that the charges collected by the finger electrodes F can be taken out to the outside with a low loss and cross each finger electrode F. The finger electrode F and the bus electrode B are set to have the same height for reasons of the post-process and device performance. Typically, the widths of the bus electrode B and the finger electrode F are about 2 mm and 100 μm, respectively. These heights are both about 20 μm.

  Next, a method for manufacturing the above-described solar cell module M using the electrode forming apparatus 1 described above will be described. In the electrode forming apparatus 1, tanks 525 and 725 are preliminarily filled with a coating solution prepared including the electrode materials of the finger electrodes F and the bus electrodes B, and this is applied to the substrate W on which the photoelectric conversion layer is formed. By doing so, it is possible to manufacture the solar cell module M.

  As the coating solution, a paste-like mixed solution having conductivity and photocurability, for example, containing conductive particles, an organic vehicle (a mixture of solvent, resin, thickener, etc.) and a photopolymerization initiator is used. it can. The conductive particles are, for example, silver powder as a material of the electrode, and the organic vehicle contains ethyl cellulose as a resin material and an organic solvent. Further, the viscosity of the coating solution is preferably, for example, 50 Pa · s (pascal second) or less before performing the curing process by light irradiation, and is preferably 350 Pa · s or more after performing the curing process. The composition of the coating liquid filled in the two tanks 525 and 725 may be the same, or a coating liquid having a different composition may be prepared for each.

  FIG. 5 is a flowchart showing a method of manufacturing a solar cell module by this electrode forming apparatus. First, the substrate W is carried into the apparatus 1 and placed on the stage 3 (step S101). Then, the stage moving mechanism 2 is operated to move the substrate W to a predetermined drawing start position (the position of the substrate W in FIG. 1) such that the right end thereof is in the vicinity of the position immediately below the first head portion 5 (step S102). ).

  Next, while moving the substrate W in the X direction, the discharge of the coating liquid and the light irradiation from the discharge nozzle unit 52 and the light irradiation unit 53 provided in the first head unit 5 are started (step S103). When the coating liquid is discharged from each tip nozzle 521, the coating liquid is applied onto the substrate W in a wide stripe pattern corresponding to the opening width of the discharge port 521a of the tip nozzle 521. Further, by irradiating with ultraviolet rays from a light irradiation unit 53 provided on the downstream side of the discharge nozzle unit 52 in the substrate moving direction, the coating liquid on the substrate W is cured and a conductive electrode is formed. This electrode becomes the bus electrode B.

  For the electrode formed by curing the coating solution, the height from the upper surface of the substrate W is detected by the height detection sensor 54 provided on the downstream side of the light emission irradiation unit 53 in the substrate movement direction (step S104). If the coating conditions and the light irradiation conditions are constant, the height of the formed electrode is considered to be substantially constant. Therefore, it is not always necessary to detect the height, and representative sampling may be performed at several locations.

  When the application of the coating liquid and the light irradiation from one end to the other end of the substrate W are completed, the above operation is repeated as many times as necessary (return to the drawing start position until the electrodes are completely formed on the entire surface of the substrate W (example of the module in FIG. 4). (Two times) is repeated (step S105). At this time, the necessary number of stripe patterns can be formed by moving the position of the substrate W by a predetermined amount in the Y direction every time one operation is completed. Thus, the bus electrode B is formed.

  Subsequently, the finger electrode F is formed. At the time when the formation of the bus electrode B is completed, the left end of the substrate W in FIG. 1 is at a position where it passes directly under the first head portion 5. At this time, the positions of the two frames 121 and 122 are set so that the right end of the substrate W comes to a position immediately below the second head portion 7. Here, the θ rotation mechanism 23 is operated to rotate the substrate W 90 degrees around the Z axis (vertical axis) (step S106). By doing so, the finger electrode F to be formed next can be made to intersect with the bus electrode B that has already been formed at a substantially right angle. The crossing angle of the electrodes can be arbitrarily determined by the rotation angle of the stage 3.

  Next, based on the height detection result of the bus electrode B detected previously, the scanning profile of the second head unit 7 with respect to the substrate W in the formation of the finger electrode is set (step S107). In this embodiment, when the discharge nozzle portion 72 of the second head portion 7 crosses the bus electrode B that has already been formed, the discharge port 721a passes through in a state of being very close to the top surface of the bus electrode B. 2 Control the distance between the head portion 7 and the substrate W.

  This is because the top surface of the bus electrode B closes the discharge port 721a when the discharge port 721a crosses over the bus electrode B, and the discharge of the coating liquid from the discharge port 721a is restricted, so that the top surface of the bus electrode B is further increased. This is to prevent the coating liquid from being poured. If a coating solution is further applied onto the formed bus electrode B and cured by light irradiation, the height of the electrode is not constant, and the intersection portion is greatly different from other portions.

  In contrast, in this embodiment, the ejection port 721a passes over the bus electrode B while facing the top surface of the bus electrode B in a very close state. In this embodiment, the discharge port 721a is closed at the top surface of the bus electrode B to prevent the coating solution from being applied to the top surface of the bus electrode B, and the coating solution is scraped off at the bottom surface of the discharge port 721a. In this way, an electrode with almost the same height is obtained by suppressing the rise at the intersection. A process for enabling this is a scan profile setting process. The scanning profile is information indicating how the interval between the second head unit 7 and the substrate W is set with respect to time when the second head unit 7 is scanned and moved with respect to the substrate W. It can be expressed as a locus to be drawn by the discharge port 721a with respect to the substrate W.

  FIG. 6 is a diagram showing an example of a scanning profile. The height of the coating liquid ejected from the ejection port 721a that opens directly below on the substrate W is influenced by the viscosity of the ejection liquid, the ejection amount, and the scanning speed, as well as the height of the ejection port 721a from the substrate W. It also changes depending on the situation. Therefore, first, the height Hg of the discharge port 721a from the substrate W is set so that the height H2 of the coating liquid A2 becomes the same as the height detection result H1 of the bus electrode B that has already been formed. In this way, first, the height of the finger electrode F at a position away from the bus electrode B can be made equal to the height of the bus electrode B.

  Next, a condition when the tip nozzle 721 passes over the bus electrode B is determined. As described above, it is desirable that the ejection port 721a crosses the bus electrode B in a state where it is separated from the top surface of the bus electrode B by a minute distance. Here, the allowable maximum value of the bulge amount allowed at the intersection of the electrodes in the specification of the module M is assumed to be H0 (for example, 5 μm). In other words, it is assumed that the height of the electrode at the intersection portion is (H1 + H0) up to (H1 + H0) with respect to the height H1 of the bus electrode B. Therefore, the distance between the discharge port 721a and the upper surface of the substrate W when the tip nozzle 721 passes over the bus electrode B may be determined so that the amount of swell of the electrode at the intersection is H0 or less. Although it may be possible to temporarily stop the discharge of the coating liquid when the tip nozzle 721 passes over the bus electrode B, the discharge timing of the coating liquid from the discharge port 721a is finely controlled by opening and closing the control valve 54. That's difficult and unrealistic.

  As shown in FIG. 6A, the distance Hg between the discharge port 721a and the substrate W required to set the height H2 of the coating liquid A2 to the height H1 of the formed bus electrode B is determined by the coating liquid A2. Consider the case where it is slightly larger than the height H2. More specifically, the distance ΔHa (= Hg−H2) between the discharge port 721a and the top surface of the coating liquid A2 is equal to or less than the allowable maximum value H0.

  In this case, the second head unit 7 may be scanned and moved with respect to the substrate W while the height Hg of the ejection port 721a from the substrate W is kept constant. This is because the thickness of the coating liquid applied to the top surface Ba of the bus electrode B when the tip nozzle 721 crosses the bus electrode B is about ΔHa and is within the allowable maximum value H0. Therefore, the scanning profile Pa in this case can be expressed as a straight line parallel to the upper surface of the substrate W as shown in FIG.

  On the other hand, as shown in FIG. 6B, the interval Hg between the discharge port 721a and the substrate W required to obtain the height of the coating liquid A2 equal to the height H1 of the bus electrode B is larger than the above. Think. More specifically, this is a case where the interval ΔHa (= Hg−H2) between the discharge port 721a and the top surface of the coating liquid A2 exceeds the allowable maximum value H0. In this case, if the tip nozzle 721 is scanned and moved while maintaining the interval Hg, a coating liquid having a height exceeding the allowable maximum value H0 is applied onto the bus electrode B. Therefore, when crossing the bus electrode B, it is necessary to reduce the interval between the ejection port 721a and the substrate W and bring them closer together. At this time, the interval between the discharge port 721a and the substrate W is determined so that the interval between the discharge port 721a and the top surface Ba of the bus electrode B is equal to or less than the allowable maximum value H0. Therefore, the scanning profile Pb in this case is a locus that is high at a position away from the bus electrode B and descends in the vicinity of the bus electrode B, as shown in FIG.

  Further, particularly when the viscosity of the coating liquid is high, as shown in FIG. 6C, in order to obtain the height H2 of the coating liquid A2, the distance Hg between the discharge port 721a and the substrate W is set to It may be necessary to make it smaller than the height H2. That is, ΔHa (= Hg−H2) <0 at this time. In this case, in order to prevent the lower end from coming into contact with the bus electrode B when the tip nozzle 721 crosses the bus electrode B, it is necessary to widen the gap before the bus electrode B and return it again after passing. Therefore, the scanning profile indicated by the symbol Pc in FIG.

  Returning to FIG. 5, the description of the flowchart will be continued. Prior to the formation of the finger electrode F, the control unit 6 sets a scanning profile file as described above based on the detection result of the height detection sensor 54 (step S107). Then, while moving W in the X direction again, this time, the coating liquid is discharged and light is emitted from the discharge nozzle portion 72 and the light irradiation portion 73 provided in the second head portion 7 (step S108). At this time, the coating liquid discharged from the discharge nozzle portion 72 is applied to the substrate W. Since the substrate W has been rotated 90 degrees first, the relative movement direction of the second head portion 7 with respect to the substrate W is The moving direction of one head unit 5 is 90 degrees. Therefore, new coating is performed so as to be orthogonal to the bus electrode B already formed on the substrate W.

  At this time, the interval between the ejection port 721a and the substrate W is controlled in synchronization with the scanning movement in accordance with the previously defined scanning profile. As a result, as shown in FIG. 6D, the height H2 of the finger electrode F to be formed later can be made equal to the height H1 of the bus electrode B, and the swell amount Hc at the intersection of the two is obtained. Can be suppressed to an allowable range H0 or less. In particular, in this embodiment, since the wide bus electrode B is formed first, the opening length in the X direction of the tip nozzle 721 for finger electrode formation is smaller than the bus electrode width. For this reason, when the discharge port 721a is opposed to the top surface Ba of the bus electrode B, the discharge port 721a is almost completely closed. As a result, application of the coating liquid onto the bus electrode B can be almost completely eliminated. Note that the interval between the discharge port 721a and the substrate W is actually adjusted by moving the stage 3 and the substrate W up and down by the stage elevating mechanism 24 instead of moving the second head unit 7.

  When application of the coating liquid and light irradiation are thus completed from one end to the other end of the substrate W, four striped finger electrodes F perpendicular to the bus electrodes B are formed on the substrate W. The necessary number of finger electrodes F can be formed by repeating the above operation a required number of times while changing the Y-direction position of the substrate W (step S109). Thus, finger electrodes F are formed on the entire surface of the substrate. About the board | substrate W which completed formation of an electrode, the manufacture of the solar cell module M is completed by carrying out out of an apparatus (step S110).

  As described above, in this embodiment, it is possible to manufacture a solar cell module M having an electrode pattern in which a narrow finger electrode F and a wide bus electrode B are crossed on a substrate W. In this embodiment, when the discharge nozzle portion 72 for finger electrodes crosses the previously formed bus electrode B, the discharge port 721a passes through in a state of being close to and opposed to the top surface Ba of the bus electrode B. Since the distance between 721a and the substrate W is controlled, the swell of the electrode at the intersection of the finger electrode F and the bus electrode B can be reduced. Therefore, it is not necessary to remove the intersection portion of the previously formed electrodes, and the process is simple. In addition, the electrode material is not wasted.

  More specifically, since the interval between the discharge port 721a and the substrate W is set based on the detected height H1 of the bus electrode B and the allowable maximum value H0 of the bulge amount of the electrode at the intersection, the electrode at the intersection It is possible to ensure that the amount of swell is within an allowable range. Further, since the interval between the discharge port 721a and the substrate W is set so as to obtain the finger electrode F having the same height as the previously formed bus electrode B except in the vicinity of the bus electrode B, the finger electrode F And the bus electrode B can be made to have the same height.

  It should be noted that the order of forming the bus electrode B and the finger electrode F may be any in principle, but in this embodiment, the bus electrode B is formed first. The reason is as follows.

  First, the number of finger electrodes F formed is larger than the number of bus electrodes B formed. If a large number of electrodes are formed first, in the electrode formation performed later, the number of electrodes that the tip nozzle 721 should cross is increased, and the scanning profile becomes complicated and the control becomes complicated. By forming the bus electrodes B (two) having a small number first, it is only necessary to cross the bus electrodes twice when forming the finger electrodes, so that the control becomes easier than the reverse case.

  Second, the width of the finger electrode F formed later is smaller than the width of the bus electrode B formed first. Rather than controlling the distance between the nozzle and the substrate when forming a wide bus electrode according to the height of the finger electrode F with a small width, the finger electrode F when forming a finger electrode with a small width according to the height of the wide bus electrode B is used. It is easier and more accurate to perform the interval control. If the crossing angle of the electrodes is not a right angle, the width of the electrode formed earlier along the scanning movement direction of the nozzle in the subsequent electrode formation and the electrode formed later in the previous electrode formation This is a comparison with the width along the direction perpendicular to the nozzle movement direction.

  Third, the discharge port 521a of the front nozzle 521 for forming the bus electrode has a larger opening area than the discharge port 721a of the front nozzle 721 for forming the finger electrode. When the opening area of the discharge port is large, the discharge amount of the coating liquid is also large, so that it becomes difficult to control, and it is easier to perform the interval control in the tip nozzle 721 for finger electrode formation with a smaller discharge amount. Further, even when a part of the coating liquid spreads in a direction different from the scanning direction when the interval is polarized, if the ejection amount is small, the pattern disturbance is small.

  Further, although this embodiment is not applicable, the control becomes more difficult when the length of the discharge port of the nozzle for forming the electrode to be performed later is larger than the width of the previous electrode to be traversed. This is because even when the discharge port is directly above the previously formed electrode, the top surface of the electrode cannot block the entire opening surface of the discharge port, and the coating liquid flows out from the gap to form a pattern. Because there is a possibility of disturbance. In this sense, as in the present embodiment, it is desirable that the opening length of the nozzle discharge port is smaller than the width of the pattern to be traversed.

  As described above, in this embodiment, the upper surface of the substrate W corresponds to the “coating surface” of the present invention, and the bus electrode B and the finger electrode F are the “first electrode” and “second electrode” of the present invention. Corresponds to "electrode". The extending directions of the bus electrode B and the finger electrode F correspond to the “first direction” and the “second direction” of the present invention, respectively.

  In this embodiment, the tip nozzles 521 and 721 function as the “first electrode nozzle” and the “second electrode nozzle” of the present invention, respectively. The control unit 6 functions as the “control unit” of the present invention, and the light irradiation unit 73 functions as the “light irradiation unit” of the present invention. In this embodiment, the height detection sensor 54 functions as the “height detection means” of the present invention.

  In the flowchart shown in FIG. 5, steps S103 and S108 correspond to the “first process” and “second process” of the present invention, respectively, and step S104 corresponds to the “detection process” of the present invention. .

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above embodiment, the present invention is applied to an apparatus for manufacturing a solar cell module M having electrodes in which finger electrodes F and bus electrodes B are orthogonal to each other. However, the present invention can be applied to the purpose of forming a pattern different from the above as long as two or more kinds of electrodes intersecting each other are included.

  Moreover, in the said embodiment, although the bus electrode W and the finger electrode F are formed sequentially with respect to the board | substrate W in which the electrode is not formed, you may form previously about the electrode. That is, the present invention can also be applied to an electrode forming apparatus that accepts a substrate on which an electrode is already formed and newly forms an electrode that intersects an existing electrode. In this case, the first head unit 5 is not necessary, but a height detection sensor for detecting the height of the existing electrode is still necessary.

  Moreover, in the said embodiment, the height of the bus electrode B just after hardening by light irradiation is detected by the height detection sensor 54, and the finger electrode is formed after setting the scanning profile based on the detection result. However, it is not limited to this. For example, a height detection sensor may be provided on the second head portion side, and the height of the second head portion may be controlled by feedback control based on the output of the height detection sensor without setting a scanning profile in advance. Further, for example, a frame for installing a height detection sensor may be provided separately, and the substrate height may be conveyed to the detection position to detect the electrode height.

  Further, the electrode height may not be formed for each treatment. If the application condition and the light irradiation condition by the first head unit 5 are determined, the height of the electrode to be formed is also substantially determined. For example, these conditions are fixed and the electrode is experimentally formed in advance to detect the height. Further, based on the result, conditions for the later electrode formation (interval between the discharge port and the substrate) may be set.

  Moreover, in the said embodiment, although light is irradiated with respect to the coating liquid containing a photocurable resin, the coating liquid is hardened and the electrode is obtained, but with respect to a coating liquid containing a photocurable resin and a coating liquid It is not an essential requirement to perform light irradiation.

  In the second head portion 7 of the above embodiment, the discharge nozzle portion having four tip nozzles is provided, but the number of tip nozzles is not limited to this and is arbitrary. Conversely, the tip nozzle of the first head unit 5 is not limited to one. For example, a plurality of tip nozzles having the same shape as the tip nozzle 721 provided in the second head portion 7 are arranged close to each other in the Y direction, and the coating liquid discharged from the plurality of tip nozzles comes into contact with each other to increase the width. You may make it become an electrode. In this case, since the shape of the tip nozzle is all common, it is possible to reduce the manufacturing cost of the apparatus and improve the maintainability.

  In each of the above embodiments, the wiring is formed only on one surface of the substrate W. However, the present invention can be applied to the case where the wiring is formed on both surfaces of the substrate W.

  In each of the above embodiments, electrode wiring is formed on a silicon substrate to produce a photoelectric conversion device as a solar cell, but the substrate is not limited to silicon. For example, the present invention can also be applied when forming an electrode on a thin film solar cell formed on a glass substrate or a device other than a solar cell.

  The present invention can be applied to an apparatus and a method for forming electrodes on a substrate, particularly a solar cell substrate, and can be suitably applied particularly when forming electrodes that cross each other on the substrate.

6 Control unit (control means)
54 Height detection sensor (height detection means)
73 Light irradiation part (light irradiation means)
521 Tip nozzle (Nozzle for first electrode)
721 Tip nozzle (second electrode nozzle)
B bus electrode (first electrode)
F finger electrode (second electrode)
S103 First step S104 Detection step S108 Second step W Substrate

Claims (12)

A nozzle for a first electrode that forms a first electrode on the coated surface by discharging a coating liquid containing an electrode material to the coated surface while moving relative to the coated surface of the substrate in a first direction;
The coating liquid containing the electrode material is discharged onto the coated surface while moving relatively in a second direction different from the first direction with respect to the coated surface on which the first electrode formed by curing the coating liquid is formed. A second electrode nozzle for forming a second electrode intersecting the first electrode on the coated surface ;
A height detecting means for detecting a height of the top surface of the first electrode from the coated surface;
Control means for controlling an interval between the coated surface and the second electrode nozzle based on a detection result of the height detection means ,
When the second electrode nozzle passes through the position facing the first electrode before SL on the substrate, opposed close the discharge port of the control means the nozzle for the second electrode on said top surface of said first electrode Then , the discharge port is closed by the top surface .   The first electrode nozzle discharges the coating solution containing a photocurable resin, and the coating solution applied to the coated surface is irradiated with light from the first electrode nozzle to cure the coating solution. The electrode forming apparatus according to claim 1, further comprising a curing unit. A coating liquid containing an electrode material is applied to the substrate on which the first electrode extending along the first direction is moved in a second direction different from the first direction with respect to the surface of the substrate on which the substrate is formed. A second electrode nozzle that forms a second electrode that intersects the first electrode on the coated surface by discharging to the coated surface;
A height detecting means for detecting a height of the top surface of the first electrode from the coated surface;
The distance between the coated surface and the second electrode nozzle is controlled based on the detection result of the height detection means, and the second electrode nozzle passes through a position facing the first electrode on the substrate. wherein the second outlet of the electrode nozzle in close proximity facing the top surface of the first electrode, the electrode forming apparatus, characterized in that said discharge port and a control means for Ru is closed by the top surface when. The opening surface of the discharge port of the second electrode nozzle, the electrode forming apparatus according to any one of claims 1 is substantially parallel to the coated surface 3. The opening length of the discharge port along the second direction, the electrode forming apparatus according to any one of 4 claims 1 smaller than the width of the first electrode along the second direction. The said 2nd electrode nozzle discharges the said coating liquid containing photocurable resin, and is provided with the light irradiation means to light-irradiate with respect to the said coating liquid apply | coated to the said to-be-coated surface from the said 2nd electrode nozzle. The electrode forming apparatus according to any one of 1 to 5 . Forming a first electrode extending along a first direction on a surface of the substrate;
A detection step of detecting a height of the top surface of the first electrode formed in the first step from the substrate surface;
A second electrode that intersects the first electrode by moving a nozzle for discharging a coating solution containing an electrode material in a second direction different from the first direction with respect to the surface of the substrate on which the first electrode is formed. A second step of forming
In the second step, an interval between the surface to be coated and the nozzle for the second electrode is controlled based on a detection result in the detection step, so that the nozzle faces the first electrode on the substrate. when passing, the discharge port of the nozzle is passed through while closely opposed to the top surface of the first electrode, the electrode forming method comprising Rukoto to close the discharge opening by the top surface. The electrode forming method according to claim 7 , wherein in the second step, an opening surface of the discharge port of the nozzle is made substantially parallel to the substrate surface. 9. The electrode forming method according to claim 7 , wherein the number of the second electrodes formed is greater than the number of the first electrodes formed. The width of the first second electrodes along the direction, the electrode forming method according to any one of the second to small claims 7 than the width of the first electrode along the direction 9. In the second step, the electrode forming method according to any one of claims 7 to 1 0 to form the second electrode at substantially the same height as the first electrode.   Predetermining an allowable maximum value of the swell amount at the intersection of the first electrode and the second electrode,
  In the second step, when the nozzle passes through a position facing the first electrode on the substrate, an interval between the discharge port of the nozzle and the top surface of the first electrode is set to be equal to or less than the allowable maximum value. The electrode forming method according to claim 7, wherein the electrode forming method is controlled.

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