Ultrasonic junction evaluation method

Abstract

To provide an ultrasonic junction evaluation method capable of performing quality determination of a bonding place with high accuracy.SOLUTION: In a step ST11, a supersonic oscillation operation is executed to a plurality of bonding places, and a bonding processing time of each of bonding places is measured. In a step ST12, a processing time of the supersonic oscillation operation against to the plurality of bonding places is recognized as a plurality of bonding processing times. In a step ST13, a bonding quality result in each of the plurality of bonding places is obtained on the basis of a comparison result of a bonding processing time and a reference processing time of the plurality of bonding places. Concretely, in the plurality of bonding places, a bonding place that the bonding processing time is a reference processing time or less is determined as a "good", and the bonding place in the case where the bonding processing time is longer than the reference processing time is determined as a "fail".SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to a method for evaluating ultrasonic bonding in an ultrasonic vibration operation using an ultrasonic vibration bonding device. [Background technology]

[0002] Conventional ultrasonic vibration bonding devices apply pressure from above to the materials to be bonded placed on the surface of a substrate and ultrasonic vibration from an ultrasonic vibration horn to bond the materials to the surface of the substrate. Examples of such ultrasonic vibration bonding devices include the ultrasonic bonding device disclosed in Patent Document 1 and the ultrasonic vibration bonding device disclosed in Patent Document 2.

[0003] Conventional ultrasonic vibration bonding devices perform an ultrasonic vibration operation in which ultrasonic vibration is applied to materials to be bonded using an ultrasonic vibration horn. To perform the ultrasonic vibration operation, an oscillation signal, which is an electric signal, is sent from an ultrasonic oscillator to a converter, which converts the electric signal into ultrasonic vibration, and the obtained ultrasonic vibration is applied to the ultrasonic vibration horn.

[0004] The ultrasonic oscillator outputs an oscillation signal that oscillates at a set oscillation frequency to the converter. The oscillation signal is an electrical signal such as a voltage or current.

[0005] In the conventional ultrasonic vibration bonding device, when bonding multiple bonding points at a fixed pitch on a bonding surface extending in a specific direction, there was a possibility that a first defective point where bonding could not be performed or a second defective point where the bonding material was broken could occur. As a result of the investigation into the cause, it was found that the occurrence of the above-mentioned first and second defective points was due to the frictional resistance of the materials to be bonded. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2022-61631 A [Patent Document 2] International Publication No. 2018 / 025362 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional ultrasonic vibration bonding devices use an energy control method as their ultrasonic control method. In other words, conventional ultrasonic control methods use an operation continuation process that continues ultrasonic vibration operation until the consumed energy calculated from the oscillation signal from the ultrasonic oscillator reaches a preset energy (threshold energy). The above-mentioned consumed energy (W s) is defined as the product of the electrical output value (W (att)) and time (s (econd)).

[0008] Fig. 14 is a graph showing the control content of a conventional ultrasonic control method. In the figure, the horizontal axis indicates time (ms) and the vertical axis indicates electrical output value (Power (W)). Fig. 14 shows the change over time of output information SC11 and SC12 in two connection cases (case 11, case 12).

[0009] Here, output information SC11 is an electrical output value (W) for causing the ultrasonic vibration horn to perform an ultrasonic vibration operation in case 11, and output information SC12 is an electrical output value (W) for causing the ultrasonic vibration horn to perform an ultrasonic vibration operation in case 12.

[0010] Case 11 shows the change over time of the output information SC11 when the frictional resistance of the materials to be joined is relatively small, and case 12 shows the change over time of the output information SC12 when the frictional resistance is relatively large. The "frictional resistance of the materials to be joined" is the total frictional resistance at the contact surface between the materials to be joined and the ultrasonic vibration horn (hereinafter, sometimes simply referred to as the "contact surface") and the joining surface between the materials to be joined and the substrate (hereinafter, sometimes simply referred to as the "joining surface"). The frictional resistance is determined by the smaller of the first frictional resistance at the contact surface and the second frictional resistance at the joining surface.

[0011] In case 11, since the frictional resistance is relatively small, the rate of increase in the output information SC11 becomes gradual, and at time t12 when the output information SC11 reaches the output value W1, the consumed energy ΣE1 reaches the energy threshold EX, and the ultrasonic vibration operation ends.

[0012] In case 12, since the frictional resistance is relatively large, the rate of increase in the output information SC2 is relatively steep, and at time t11 when the output value W9 is reached, the consumed energy ΣE2 reaches the energy threshold EX, and the ultrasonic vibration operation ends.

[0013] As described above, in the conventional ultrasonic control method, if there is variation in the frictional resistance of the materials to be joined, variation will occur in the processing time of the ultrasonic vibration operation (times t11, t12) and the final electrical output values ​​(output values ​​W1, W9) indicated by the output information SC (SC1, SC2).

[0014] As a result, conventional ultrasonic vibration bonding devices had a problem in that if there was variation in the frictional resistance of the workpieces among multiple bonding locations, the workpieces could not be bonded well by the ultrasonic vibration action of the ultrasonic vibration horn.

[0015] The ultrasonic vibration bonding device used in the ultrasonic bonding evaluation method disclosed herein has been made to solve the above-mentioned problems, and is an improved ultrasonic vibration bonding device that can satisfactorily bond the workpieces through the ultrasonic vibration action of an ultrasonic vibration horn, even if there is variation in the frictional resistance of the workpieces.

[0016] An object of the present disclosure is to provide an ultrasonic bonding evaluation method capable of accurately determining the quality of an ultrasonically bonded joint during ultrasonic vibration operation using an improved ultrasonic vibration bonding device. [Means for solving the problem]

[0017] The ultrasonic bonding evaluation method according to the present disclosure is an ultrasonic bonding evaluation method in an ultrasonic vibration operation using an ultrasonic vibration bonding device, comprising: (a) a step of performing an ultrasonic vibration operation using the ultrasonic vibration bonding device to apply ultrasonic vibration to a joining point of materials to be joined that are placed on a substrate, the ultrasonic vibration being generated based on an electrical signal including an electrical output value, and the ultrasonic vibration operation being performed at the joining point until the electrical output value reaches an output threshold value; (b) a step of recognizing a processing time of the ultrasonic vibration operation for the joining point as a joining processing time; and (c) a step of obtaining a joining pass / fail result for the joining point based on a result of comparing the joining processing time with a reference processing time. Effect of the Invention

[0018] In the ultrasonic bond evaluation method disclosed herein, in order to obtain a bond pass / fail result in step (c), by setting an appropriate reference processing time, it is possible to obtain a highly accurate bond pass / fail result for the bonded portion. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is an explanatory diagram illustrating a schematic configuration of an ultrasonic vibration bonding device according to a first embodiment. [Diagram 2] FIG. 2 is an explanatory diagram illustrating the ultrasonic oscillator shown in FIG. 1 and its periphery. [Diagram 3] 5 is a flowchart showing a processing procedure of a control operation in the ultrasonic vibration bonding apparatus of the first embodiment. [Figure 4] 4 is a graph showing the control content of an ultrasonic control method in the ultrasonic vibration bonding device of the first embodiment. [Diagram 5] FIG. 11 is an explanatory diagram illustrating a schematic diagram of an ultrasonic oscillator and its periphery in a second embodiment. [Figure 6] 10 is a flowchart showing a control procedure of an ultrasonic control method in a conventional ultrasonic vibration bonding device. [Figure 7] FIG. 2 is an explanatory diagram showing an aluminum lead wire serving as a joined material and its surroundings. [Figure 8]13 is a flowchart showing a processing procedure of an ultrasonic bonding evaluation method according to a third embodiment. [Figure 9] 1 is a flowchart showing a general manufacturing process for a solar cell. [Figure 10] FIG. 11 is an explanatory diagram showing, in table form, the evaluation results of the ultrasonic bonding evaluation method according to the third embodiment. [Figure 11] 13 is a flowchart showing a processing procedure of an ultrasonic bonding evaluation method according to a fourth embodiment. [Figure 12] 12 is a flowchart showing details of a reference processing time setting process shown in FIG. 11. [Figure 13] FIG. 13 is an explanatory diagram showing, in table form, experimental results during the process of setting the reference processing time according to the fourth embodiment. [Figure 14] 1 is a graph showing the control content of a conventional ultrasonic control method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] <Principles of the Disclosure> Conventional ultrasonic vibration bonding devices use an energy control method as the ultrasonic control method, which results in variations in the operating time of the ultrasonic vibration operation (t12>>t11) and the final electrical output value (W9>>W1) when bonding multiple joints, as shown in Figure 14.

[0021] The inventors of the present application focused on the electrical output value contained in the oscillation signal rather than the energy calculated from the oscillation signal, and assumed that an ideal output value WR exists for joining materials to be joined.

[0022] As in case 11 shown in Figure 14, when the frictional resistance between the ultrasonic vibration horn and the workpiece is lower than usual, the output value W1 falls far below the ideal output value WR, and as a result, it is considered that the workpieces cannot be joined well even if the ultrasonic vibration operation is performed for a relatively long time.

[0023] On the other hand, when the frictional resistance of the workpiece is larger than normal, as in case 12 in Fig. 14, the output value W9 greatly exceeds the ideal output value WR, and as a result, it is highly likely that the workpiece will be damaged. For example, if the workpiece is a metal foil, it is highly likely that the metal foil will be destroyed.

[0024] In this way, in the energy control method in which the energy threshold EX is set as the termination condition, when the frictional resistance is too large or too small compared to normal, it is not possible to perform good joining of the workpieces by ultrasonic vibration. In other words, when the frictional resistance varies among multiple joining points, the energy control method cannot cope with this.

[0025] Therefore, the inventors of the present application found that an effective control method is to set an output threshold value WX that matches the ideal output value WR in advance, and to continue the ultrasonic vibration operation until the electrical output value of the oscillation signal reaches the output threshold value WX. The ultrasonic vibration bonding apparatus that adopts the output control method as the ultrasonic control method is the first and second embodiments described below.

[0026] <Embodiment 1> FIG. 1 is an explanatory diagram that illustrates a schematic configuration of an ultrasonic vibration bonding apparatus 101 according to a first embodiment of the present disclosure, which is an ultrasonic vibration bonding apparatus.

[0027] As shown in the figure, an ultrasonic vibration bonding device 101 includes an ultrasonic vibration horn 10, a converter 11, and an ultrasonic oscillator 12 as main components.

[0028] Meanwhile, a substrate 14 is placed on a stage 20, and a material to be joined 13 is placed on the surface of the substrate 14. The material to be joined 13 may be, for example, a metal foil. An interface BF is an interface between the material to be joined 13 and the substrate 14 when they are joined. In this manner, the material to be joined 13 is placed on the stage 20 via the substrate 14.

[0029] The ultrasonic vibration horn 10 has a contact tip 10t at its tip, and performs an ultrasonic vibration operation to apply ultrasonic vibration from the bottom surface of the contact tip 10t to the workpiece 13. In parallel with the ultrasonic vibration operation, a pressurizing operation is performed in which pressure is applied to the ultrasonic vibration horn 10 toward the stage 20 by a pressurizing cylinder 6 (see FIG. 2), not shown in FIG. 1. Only the pressure force F6 during the pressurizing operation by the pressurizing cylinder 6 is shown in FIG.

[0030] The converter 11, which functions as an ultrasonic vibrator, applies ultrasonic vibration to the ultrasonic vibration horn 10. The ultrasonic oscillator 12 includes therein, as a main component, a control unit 1 that executes a control operation to control the ultrasonic vibration operation by the ultrasonic vibration horn 10.

[0031] 2 is an explanatory diagram that shows a schematic diagram of an ultrasonic oscillator 12 and its periphery. As shown in the figure, a control unit 1 in the ultrasonic oscillator 12 outputs an oscillation signal S12 including output information SC to a converter 11 as a control operation. The output information SC included in the oscillation signal S12 is an electrical output value for the ultrasonic vibration applied from the converter 11 to the ultrasonic vibration horn 10 to vibrate at a predetermined frequency. For example, when the oscillation signal S12 is a voltage signal, it is considered that the amplitude (magnitude) of the oscillation signal S12 is the output information SC.

[0032] The control unit 1 outputs an oscillation signal S12 as a control signal to the converter 11. The converter 11, which functions as an ultrasonic transducer, applies ultrasonic vibration to the ultrasonic vibration horn 10 based on the oscillation signal S12.

[0033] As a result, the ultrasonic vibration horn 10 can perform an ultrasonic vibration operation that applies ultrasonic vibration to the workpiece 13 from the bottom surface (joining surface) of the contact tip portion 10t.

[0034] The output information SC included in the oscillation signal S12 is an electrical output value required for the ultrasonic vibration to vibrate at a predetermined frequency in the ultrasonic vibration operation of the ultrasonic vibration horn 10. The momentum of the ultrasonic vibration imparted by the converter 11 to the ultrasonic vibration horn 10 is positively correlated with the output information SC, and the larger the output information SC, the larger the momentum of the ultrasonic vibration.

[0035] In this manner, the control unit 1 controls the ultrasonic vibration operation of the ultrasonic vibration horn 10 by outputting the oscillation signal S12 as a control signal to the converter 11 as a control operation.

[0036] The control operation by the control unit 1 in the ultrasonic vibration bonding apparatus 101 of the first embodiment is characterized by including an operation continuation process for continuing the ultrasonic vibration operation until the output information SC (the electric output value indicated by the output information SC) becomes equal to or greater than the output threshold value WX.

[0037] The ultrasonic vibration horn 10 and the converter 11 have a friction resistance recognition function that recognizes the friction resistance related to the workpiece 13. As described above, the "friction resistance related to the workpiece 13" is the total friction resistance at the contact surface between the workpiece 13 and the ultrasonic vibration horn 10 and the joining surface between the workpiece 13 and the substrate 14. That is, the friction resistance is determined by the smaller of the first friction resistance at the contact surface and the second friction resistance at the joining surface. The friction resistance recognition function can be realized by an existing technology that utilizes, for example, the piezoelectric principle. A detection member for the friction resistance recognition function is provided, for example, in the ultrasonic vibration horn 10, and a feedback signal SF including friction resistance information detected by the ultrasonic vibration horn 10 is output to the control unit 1 in the ultrasonic vibration horn 10 via the converter 11.

[0038] The feedback signal SF is output at a predetermined time interval, which may be, for example, 1 ms.

[0039] In response to receiving the feedback signal SF, the control unit 1 calculates output information SC based on the frictional resistance information included in the feedback signal SF, and outputs an oscillation signal S12 including the newly calculated output information SC to the converter 11 as a control signal.

[0040] The converter 11 then applies to the ultrasonic vibration horn 10 ultrasonic vibration based on the oscillation signal S12 including the newly obtained output information SC.

[0041] During the execution of the ultrasonic vibration operation, the frictional resistance information (frictional resistance value indicated by the frictional resistance information) increases, and therefore the output information SC (electrical output value indicated by the frictional resistance information) also increases. This is because there is a positive correlation between the frictional resistance information and the output information SC. The control unit 1 in the ultrasonic oscillator 12 continues to output the oscillation signal S12 including the output information SC to the converter 11 until the output information SC becomes equal to or greater than the output threshold value WX, and therefore the ultrasonic vibration operation continues to be executed.

[0042] As shown in FIG. 2, the ultrasonic vibration bonding apparatus 101 of the first embodiment is provided with a pressurizing cylinder 6 as a pressurizing mechanism, and the pressurizing cylinder 6 performs a pressurizing operation of applying a pressure F6 to the ultrasonic vibration horn 10 toward the stage 20 under the control of the control unit 1.

[0043] The control unit 1 controls the pressurizing operation of the pressurizing cylinder 6 by outputting a pressurizing control signal SP to the pressurizing cylinder 6 .

[0044] 3 is a flowchart showing the procedure of the control operation in the ultrasonic vibration bonding apparatus 101 of the embodiment 1. As described above, the control operation is performed by the control unit 1, and the ultrasonic vibration bonding apparatus 101 employs an output control method as an ultrasonic control method. Hereinafter, the processing contents of the control operation of the control unit 1 will be described with reference to FIG.

[0045] In step ST1, an output threshold value WX, which is a termination condition parameter in the output control method, is set. The output threshold value WX is set to, for example, the ideal output value WR shown in FIG.

[0046] Next, in step ST2, a pressurizing operation is started by the pressurizing cylinder 6, which is a pressurizing mechanism. Specifically, the control unit 1 outputs a pressurizing control signal SP, which instructs the pressurizing cylinder 6 to start the pressurizing operation, to the pressurizing cylinder 6, whereby the pressurizing operation by the pressurizing cylinder 6 is started.

[0047] Thereafter, in step ST3, it is recognized that the contact between the contact tip 10t of the ultrasonic vibration horn 10 and the workpiece 13 is in contact with the workpiece 13. For example, an existing detection function for detecting the presence or absence of contact between the contact tip 10t and the workpiece 13 is provided in the pressurizing cylinder 6, and when the detection function detects contact, a contact detection signal S6 indicating the contact state is output to the control unit 1, whereby the control unit 1 can recognize the contact state.

[0048] Next, in step ST4, the control unit 1 of the ultrasonic oscillator 12 outputs an oscillation signal S12 including output information SC and oscillating at a predetermined frequency to the converter 11, thereby starting ultrasonic vibration operation by the ultrasonic vibration horn 10. Note that the output information SC at the start of operation is set to a relatively small value.

[0049] In this way, steps ST3 and ST4 are steps in which the contact between the contact tip 10t and the workpiece 13 is used as a trigger to start the ultrasonic vibration operation.

[0050] Thereafter, in step ST5, when the ultrasonic vibration operation is started, the converter 11 outputs the feedback signal SF to the control unit 1 of the ultrasonic oscillator 12. As described above, the feedback signal SF includes friction resistance information indicating the friction resistance value at the contact point between the bottom surface of the contact tip portion 10t and the workpiece 13.

[0051] Based on the frictional resistance information included in the feedback signal SF, the control unit 1 newly calculates the output information SC required to apply ultrasonic vibration of a predetermined frequency to the contact point. There is a positive correlation between the frictional resistance information of the contact point (the frictional resistance value indicated by the information) and the output information SC (the electrical output value indicated by the information).

[0052] Then, in step ST6, the control unit 1 outputs the oscillation signal S12 including the output information SC to the converter 11. Then, the converter 11 applies ultrasonic vibration based on the oscillation signal S12 including the output information SC to the ultrasonic vibration horn 10.

[0053] Since the frictional resistance at the contact location increases during the execution period of the ultrasonic vibration operation, the output information SC (the electrical output value indicated) also increases. For example, when the output information SC indicates a voltage value (V), usually, since the current value (A) flowing through the converter 11 is constant, the power value (W) of the converter 11 also rises along with the voltage value.

[0054] Next, in step ST7, the output information SC (the electrical output value indicated) is compared with the output threshold value WX. When the output information SC is a voltage value, the output threshold value WX is a voltage value, and when the output information SC is a power value, the output threshold value WX is a power value. As described above, since the current value flowing through the converter 11 is constant, the voltage value and the power value are substantially equivalent electrical output values.

[0055] In step ST7, when {SC≧WX} is satisfied, the process proceeds to the next step ST8 and subsequent steps, and when {SC≧WX} is not satisfied, the process returns to step ST5.

[0056] When {SC<WX} in step ST7, thereafter, steps ST5 to ST7 are repeatedly executed until {SC≧WX} is satisfied. Thus, step ST7 is a step that repeatedly executes steps ST5 and ST6 until the output information SC becomes equal to or greater than the output threshold value WX.

[0057] Therefore, until the output information SC reaches the output threshold value WX, the output of the oscillation signal S12 effective as a control signal is continued, so the ultrasonic vibration operation by the ultrasonic vibration horn 10 is continuously executed.

[0058] In step ST8, which is executed if {SC≧WX} is satisfied in step ST7, the pressurizing operation by the pressurizing cylinder 6, which is the pressurizing mechanism, is terminated. Specifically, the pressurizing operation by the pressurizing cylinder 6 is terminated by outputting a pressurizing control signal SP from the control unit 1 to the pressurizing cylinder 6 to instruct the end of the pressurizing operation.

[0059] Thereafter, in step ST9, the ultrasonic vibration operation by the ultrasonic vibration horn 10 is terminated. For example, the output of the oscillation signal S12 to the converter 11 is stopped to terminate the ultrasonic vibration operation.

[0060] In this way, steps ST8 and ST9 are executed after the output information SC becomes equal to or greater than the output threshold value WX, and are steps for ending the pressurizing operation by the pressurizing cylinder 6 and the ultrasonic vibration operation by the ultrasonic vibration horn 10.

[0061] Fig. 4 is a graph showing the control content of the ultrasonic control method in the ultrasonic vibration bonding apparatus 101 of the embodiment 1. In the figure, the horizontal axis indicates time (ms) and the vertical axis indicates the electric output value (Power (W)). That is, in Fig. 4, the output information SC indicates the power value (W) as the electric output value.

[0062] Case 1 shows the change over time of the output information SC1 in the case where the frictional resistance of the workpiece 13 is relatively small when the ultrasonic vibration horn 10 is performing the ultrasonic vibration operation. That is, case 1 shows the control content in the case where the degree of slippage at the interface BF between the workpiece 13 and the substrate 14 is relatively large, that is, the second frictional resistance at the interface BF that becomes the joining surface is small.

[0063] On the other hand, case 2 shows the change over time of the output information SC2 when the frictional resistance is relatively large. Case 2 shows the control content when there is almost no slippage at the interface BF between the workpieces 13 and the substrate 14, for example.

[0064] In case 1, since the frictional resistance is relatively small, the rate of increase of the output information SC1 becomes relatively gradual, and at time t2, the output information SC1 reaches the output threshold value WX, and the ultrasonic vibration operation ends.

[0065] In case 2, since the frictional resistance is relatively large, the increase in the output information SC2 is relatively steep, and at time t1, the output threshold WX is reached and the ultrasonic vibration operation is terminated. A relatively large time difference dt12 exists between time t1 and time t2.

[0066] When there is almost no slippage at the interface BF (joint surface) between the joined material 13 and the substrate 14 and the frictional resistance of the joined material 13 is relatively large, the output information SC1 reaches the output threshold value WX at time t1, as shown in case 2 of Figure 4.

[0067] On the other hand, when the degree of slippage at the interface BF (joining surface) between the joined material 13 and the substrate 14 is relatively large and the frictional resistance of the joined material 13 is relatively small, as shown in case 1 of Figure 4, the output information SC2 reaches the output threshold WX at time t2, which is delayed by a time difference dt12 from time t1.

[0068] In this way, the control unit 1 of the ultrasonic vibration bonding apparatus 101 of embodiment 1 executes a control operation including an operation continuation process that continues the ultrasonic vibration operation until the output information SC (SC1, SC2) reaches the output threshold value WX, regardless of the level of frictional resistance of the workpiece 13 at the contact point.

[0069] (Conventional ultrasonic control method) Fig. 6 is a flow chart showing the control procedure of the ultrasonic control method of a conventional ultrasonic vibration bonding device. As described above, an energy control method has been used as the ultrasonic control method in the past. The processing procedure of the conventional ultrasonic control method will be explained below with reference to the same figure. Here, for convenience of explanation, it is assumed that the conventional ultrasonic vibration bonding device has a configuration similar to that shown in Figs. 1 and 2, and that a control unit similar to the control unit 1 executes the control operation.

[0070] In step ST51, an energy threshold EX is set, which is a termination condition parameter in the energy control method.

[0071] Next, in step ST52, similarly to step ST2 shown in FIG. 3, the pressurizing operation by the pressurizing cylinder 6, which is the pressurizing mechanism, is started.

[0072] Thereafter, in step ST53, similarly to step ST3 shown in FIG. 3, contact between the contact tip 10t of the ultrasonic vibration horn 10 and the workpiece 13 is recognized.

[0073] Next, in step ST54, similarly to step ST4 shown in FIG. 3, the ultrasonic vibration horn 10 starts ultrasonic vibration operation.

[0074] Thereafter, in step ST55, similarly to step ST5 shown in FIG. 3, output information SC required for applying ultrasonic vibration of a predetermined frequency to the contact location where the frictional resistance indicated by the frictional resistance information is occurring is newly calculated.

[0075] Then, in step ST56, the oscillation signal S12 including the output information SC is output to the converter 11, similarly to step ST6 shown in FIG.

[0076] Next, in step ST57, the consumed energy ΣE is calculated based on the output information SC of the oscillation signal S12. When the output information SC indicates a power value, the consumed energy ΣE is an integral value of the change over time of the output information SC.

[0077] Next, in step ST58, the consumed energy ΣE is compared with the energy threshold value EX.

[0078] In step ST58, if {ΣE≧EX} is satisfied, the process proceeds to the next step ST59, and if {ΣE≧EX} is not satisfied, the process returns to step ST55.

[0079] In step ST58, when {ΣE < EX}, steps ST55 to ST58 are repeatedly executed until {ΣE ≥ EX} is satisfied.

[0080] Therefore, until the output information ΣE reaches the energy threshold EX, the output of the effective oscillation signal S12 is continued, so the ultrasonic vibration operation by the ultrasonic vibration horn 10 is continuously executed.

[0081] In step ST59, which is executed when {ΣE ≥ EX} is satisfied in step ST58, similar to step ST8 shown in FIG. 3, the pressurizing operation by the pressurizing cylinder 6 is terminated.

[0082] Thereafter, in step ST60, similar to step ST9 shown in FIG. 3, the ultrasonic vibration operation by the ultrasonic vibration horn 10 is terminated.

[0083] Thus, the conventional ultrasonic control method employs an energy control method. For this reason, as in case 11 shown in FIG. 14, the ultrasonic vibration operation may end at time t12 when the output information SC11 is much lower than the ideal output value WR (≈ WX), or as in case 12 shown in FIG. 14, the ultrasonic vibration operation may finally end at t11 when the output information SC12 is much higher than the ideal output value WR.

[0084] (Effect) The control operation executed by the control unit 1 in the ultrasonic oscillator 12 in the ultrasonic vibration bonding apparatus 101 of Embodiment 1 includes an operation continuation process of continuing the ultrasonic vibration operation until the output information SC becomes equal to or higher than the output threshold value WX.

[0085] Therefore, during the execution period of the ultrasonic vibration operation, the converter 11 can always apply ultrasonic vibration based on the oscillation signal S12 including the output information SC equal to or higher than the output threshold value WX to the ultrasonic vibration horn 10.

[0086] For example, in case 2 shown in Fig. 4, the output information SC2 reaches the output threshold value WX at time t1, and in case 1 shown in Fig. 4, the output information SC1 reaches the output threshold value WX at time t2 delayed by a time difference dt12 from time t1. That is, the ultrasonic vibration bonding device of the first embodiment does not end the ultrasonic vibration operation at the output value W1 where the output information SC11 is significantly lower than the ideal output value WR corresponding to the output threshold value WX, as in case 11 shown in Fig. 14.

[0087] As a result, by appropriately setting the output threshold WX, the ultrasonic vibration bonding apparatus 101 of the first embodiment can satisfactorily bond the workpiece 13 onto the surface of the substrate 14 by the ultrasonic vibration action of the ultrasonic vibration horn 10.

[0088] Therefore, when joining multiple joining points of the workpiece 13, even if there is variation in the frictional resistance of the workpiece 13 between the multiple joining points, the ultrasonic vibration joining device 101 of embodiment 1 can join each of the multiple joining points well.

[0089] For example, by performing an experiment in which a plurality of joining points are joined on an experimental workpiece similar to the workpiece 13 using the ultrasonic vibration joining device 101, it is possible to obtain an output threshold value WX that provides an output value that allows good joining regardless of the level of friction resistance of the workpiece 13 at the contact points. As the output threshold value WX, for example, the ideal output value WR shown in FIG.

[0090] In response to receiving the feedback signal SF, the control unit 1 in the ultrasonic vibration bonding apparatus 101 of embodiment 1 calculates output information SC based on the frictional resistance information contained in the feedback signal SF, and outputs the oscillation signal S12 including the newly calculated output information SC as a control signal.

[0091] Therefore, the control unit 1 in the ultrasonic vibration bonding apparatus 101 of the first embodiment can always output to the converter 11 the oscillation signal S12 including the output information SC reflecting the frictional resistance information included in the feedback signal SF.

[0092] As a result, the ultrasonic vibration bonding apparatus 101 of embodiment 1 can apply ultrasonic vibrations that always vibrate at a predetermined frequency to the workpiece 13 by the ultrasonic vibration horn 10 by causing the ultrasonic vibration horn 10 to perform ultrasonic vibration operation via the converter 11.

[0093] The control unit 1 in the ultrasonic vibration bonding apparatus 101 of embodiment 1 executes control operations including steps ST1 to ST9 shown in FIG. 3, thereby quickly terminating the pressurizing operation by the pressurizing cylinder 6 and the ultrasonic vibration operation by the ultrasonic vibration horn 10 when the output information SC reaches or exceeds the output threshold value WX.

[0094] The ultrasonic vibration bonding apparatus 101 of the first embodiment can cause the ultrasonic vibration horn 10 to perform ultrasonic vibration operation by outputting an oscillation signal S12 as a control signal from the control unit 1 included in the ultrasonic oscillator 12 to the converter.

[0095] <Embodiment 2> Fig. 5 is an explanatory diagram showing a schematic diagram of an ultrasonic oscillator 12B and its periphery provided in an ultrasonic vibration bonding apparatus 102 according to the embodiment 2. The overall configuration of the ultrasonic vibration bonding apparatus 102 is similar to that of the ultrasonic vibration bonding apparatus 101 according to the embodiment 1 shown in Fig. 1, except that the ultrasonic oscillator 12 is replaced with an ultrasonic oscillator 12B.

[0096] Hereinafter, the same components as those of the ultrasonic oscillator 12 of the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted as appropriate, and the description will be centered on the characteristic components of the ultrasonic oscillator 12B of the second embodiment.

[0097] As shown in FIG. 5, a control unit 1B in an ultrasonic oscillator 12B outputs an oscillation signal S12 indicating output information SC to a converter 11, similar to the control unit 1 in the first embodiment.

[0098] The ultrasonic oscillator 12B includes as a main component a timer 2 in addition to the control unit 1B. The control unit 1B receives time information S2 indicating the passage of time from the timer 2, recognizes the processing time of the ultrasonic vibration operation, and outputs to the outside processing time information TP indicating the bonding processing time, which is the processing time of the ultrasonic vibration operation.

[0099] The control unit 1B constantly receives time information S2 from the timer 2, and thereby recognizes, for example, the elapsed time from the start time of the ultrasonic vibration operation in step ST4 shown in FIG. 3 to the end time of the ultrasonic vibration operation in step ST9 as the processing time of the ultrasonic vibration operation.

[0100] Then, the control unit 1B outputs, to the outside of the ultrasonic vibration bonding apparatus 102, processing time information TP indicating a bonding processing time, which is the processing time of the ultrasonic vibration operation.

[0101] Since the control unit 1B in the ultrasonic oscillator 12B in the ultrasonic vibration bonding apparatus 102 of embodiment 2 receives time information S2 from the timer 2, it is relatively easy to recognize the bonding processing time, which is the processing time of the ultrasonic vibration operation by the ultrasonic vibration horn 10, from the time information S2.

[0102] Therefore, the ultrasonic vibration bonding apparatus 102 of embodiment 2 outputs processing time information TP indicating the bonding processing time to the outside, so that a user of the ultrasonic vibration bonding apparatus 102 can use the processing time information TP as information for judging the quality of the bonding.

[0103] <Embodiment 3> By using the ultrasonic vibration bonding apparatus 101 of embodiment 1 or the ultrasonic vibration bonding apparatus 102 of embodiment 2 as an improved ultrasonic vibration bonding apparatus, an ultrasonic vibration operation can be performed on the workpieces 13 arranged on the substrate 14, applying ultrasonic vibrations to the joining points.

[0104] The ultrasonic bonding evaluation method of the third embodiment, which is an ultrasonic bonding evaluation method of the present disclosure, evaluates ultrasonic vibration operation using the ultrasonic vibration bonding apparatus 102 of the second embodiment as an improved ultrasonic vibration bonding apparatus.

[0105] Fig. 7 is an explanatory diagram showing aluminum lead wires 3 (3L, 3R) and their surroundings, which are a specific example of the joined material 13. The XYZ orthogonal coordinate system is shown in the figure. Thus, in Fig. 7, the aluminum lead wires 3, which are electrode materials used in solar cells, are shown as the joined material 13 (see Fig. 1).

[0106] 7, an electrode formation region 4a is provided on the surface of a solar cell substrate 4. A substrate formation width KH4 along the Y direction of the solar cell substrate 4 is set to, for example, 700 mm, and a substrate formation length KL4 along the X direction is set to, for example, 1600 mm. The electrode formation region 4a is provided over the entire surface of the solar cell substrate 4.

[0107] The regions extending in the X direction at both ends in the Y direction of the electrode formation region 4a are the arrangement regions for the aluminum lead wires 3. That is, in the electrode formation region 4a, the aluminum lead wire 3L is arranged in the left end region on the +Y direction side, and the aluminum lead wire 3R is arranged in the right end region on the Y direction side.

[0108] The solar cell substrate 4 is transported along the substrate transport direction D4, which is the +X direction. Therefore, in the electrode formation region 4a of the solar cell substrate 4, the aluminum lead wire 3L is arranged on the L side (left side) and the aluminum lead wire 3R is arranged on the R side (right side) with respect to the substrate transport direction D4.

[0109] The aluminum lead wire 3L has joints L(1) to L(52) set along the -X direction, and the aluminum lead wire 3R has joints R(1) to R(52) set along the -X direction. In this manner, the joints L(1) to L(52) and the joints R(1) to R(52) are provided as a plurality of joints.

[0110] Hereinafter, the aluminum leads 3L and 3R may be collectively referred to as "aluminum lead 3", the joints L(1) to L(52) may be collectively referred to as "joint L(i)", and the joints R(1) to R(52) may be collectively referred to as "joint R(j)". In the joint L(i), "i" refers to any of 1 to 52, and in the joint R(j), "j" refers to any of 1 to 52.

[0111] In this manner, a joint L(i) for the aluminum lead wire 3L and a joint R(j) for the aluminum lead wire 3R are provided as a plurality of joints for the aluminum lead wire 3.

[0112] The bonding at the bonding points L(i) is performed, for example, by placing the contact tip 10t of the ultrasonic vibration horn 10 in the ultrasonic vibration bonding device 102 above the aluminum lead wire 3L, and performing an ultrasonic vibration operation in which ultrasonic vibrations are applied to the bonding points L(i) in the order of bonding points L(1) to L(52) while moving the solar cell substrate 4 along the substrate transport direction D4 parallel to the X direction.

[0113] Similarly, bonding at bonding point R(j) is performed, for example, by positioning the contact tip 10t above the aluminum lead wire 3R, moving the solar cell substrate 4 along the substrate transport direction D4, and performing an ultrasonic vibration operation to apply ultrasonic vibrations to bonding points R(j) in the order of bonding points R(1) to R(52).

[0114] Fig. 8 is a flowchart showing the procedure of the ultrasonic bonding evaluation method according to the embodiment 3. Hereinafter, with reference to the same drawing, the processing contents of the ultrasonic bonding evaluation method in ultrasonic vibration operation using the ultrasonic vibration bonding apparatus 102 according to the embodiment 2 as an improved ultrasonic vibration bonding apparatus will be described.

[0115] First, in step ST11, ultrasonic vibration is applied to a plurality of bonding points, and the bonding process time for each of the plurality of bonding points is measured.

[0116] Specifically, an ultrasonic vibration bonding apparatus 102 is used to perform an ultrasonic vibration operation in which ultrasonic vibrations are applied to each of bonding points L(1) to L(52) and bonding points R(1) to R(52) of an aluminum lead wire 3 (3L, 3R) arranged on a solar cell substrate 4. As a result, the aluminum lead wire 3L is bonded to the electrode formation region 4a at the bonding point L(i), and the aluminum lead wire 3R is bonded to the electrode formation region 4a at the bonding point R(j).

[0117] Thus, step ST11 is a step in which ultrasonic vibration operation is performed using the ultrasonic vibration bonding apparatus 102 to apply ultrasonic vibration to multiple bonding points (L(i) and R(j)) of the aluminum lead wire 3, which is the material to be bonded and arranged on the solar cell substrate 4.

[0118] At this time, the ultrasonic vibration of the ultrasonic vibration horn 10 is generated based on an oscillation signal S12 output from the control unit 1B in the ultrasonic oscillator 12B. The oscillation signal S12 is an electrical signal and includes output information SC, which is an electrical output value. The ultrasonic vibration operation is performed at each of the joints L(1) to L(52) and the joints R(1) to R(52) until the output information SC reaches the output threshold value WX.

[0119] Since the ultrasonic vibration bonding device 102 outputs processing time information TP when performing ultrasonic vibration operation, the bonding processing time for each of the bonding points L(i) and R(j) can be easily measured by referring to the processing time information TP.

[0120] Thereafter, in step ST12, the processing time of the ultrasonic vibration operation for each of the multiple bonding points (bonding points L(1) to L(52) and bonding points R(1) to R(52)) is recognized as multiple bonding processing times. Since the processing time information TP is obtained for each bonding point in ST11, the bonding processing time during the execution of the ultrasonic vibration operation for each of the multiple bonding points can be easily recognized.

[0121] Thereafter, in step ST13, a result of the quality of the joints at each of the plurality of joints (L(i) and R(j)) is obtained based on a comparison result between the joint processing time at each of the plurality of joints and the reference processing time.

[0122] That is, for each of the multiple joints, those whose joining processing time is equal to or less than the reference processing time are judged to be "good," and those whose joining processing time is longer than the reference processing time are judged to be "bad."

[0123] The reference processing time is set based on the takt time of a process for producing solar cells, for example. Fig. 9 is a flow chart showing a general solar cell manufacturing process. The general solar cell manufacturing process will be described below with reference to Fig. 9.

[0124] First, in step ST21, a manufacturing process of the solar cell substrate 4 is performed. After step ST21 is performed, the main parts of the solar cell are fabricated in the solar cell substrate 4. The main parts of the solar cell include a back electrode, a light absorbing layer, a transparent conductive film (electrode formation region 4a), a buffer layer, and the like.

[0125] Thereafter, in step ST22, a lead wire attachment process is performed to attach the aluminum lead wires 3 and ribbons onto the solar cell substrate 4. At this time, ultrasonic vibration operation is performed on a plurality of bonding points (L(i) and R(j)) using the ultrasonic vibration bonding device 102.

[0126] Next, in step ST23, a lamination process (pressure sealing process) is performed, and in step ST24, a final assembly process is performed, which includes assembling a frame and a JBOX (junction box).

[0127] In general, a takt time is set in the solar cell manufacturing method including steps ST21 to ST24. In this case, the takt time is also set for the lead wire attachment processing time in step ST22, and a reference processing time for each of the multiple joining points (L(i) and R(j)) is set based on the takt time set in step ST22.

[0128] A bonding point where the bonding process time is longer than the reference process time set in this way has an inappropriate bonding process time in relation to the takt time set in step ST22.For this reason, in the ultrasonic bonding evaluation method of the third embodiment, a bonding point where the bonding process time is longer than the reference process time is judged to be defective regardless of the quality of the bond itself.

[0129] 10 is an explanatory diagram showing, in table form, the evaluation results obtained by the ultrasonic bonding evaluation method of the third embodiment. In the figure, bonding locations No. 1 to No. 5 are shown. The bonding location of No. 1 is bonding location R(10), the bonding location of No. 2 is bonding location R(20), the bonding location of No. 3 is bonding location L(10), the bonding location of No. 4 is bonding location L(20), and the bonding location of No. 5 is bonding location L(30). Furthermore, the output values ​​at which the output information SC finally indicates the output threshold value WX at bonding locations No. 1 to No. 5 were all 150 (W).

[0130] As shown in FIG. 10, the bonding processing time for No. 1 was 30 ms, the bonding processing time for No. 2 was 32 ms, the bonding processing time for No. 3 was 60 ms, the bonding processing time for No. 4 was 45 ms, and the bonding processing time for No. 5 was 100 ms.

[0131] 10 shows that the bonding process time for the bonding portion L(i) tends to be longer than that for the bonding portion R(j). This may be because the formation height of the left end region of the electrode formation region 4a is different from that of the other regions in the film formation process of step ST21.

[0132] In the evaluation results shown in FIG. 10, the standard processing time was set to 50 ms, and the bonding points No. 3 and No. 5, which had bonding processing times of 60 ms and 100 ms, respectively, greater than 50 ms, were judged as “fail,” while the bonding points No. 1, No. 2, and No. 4, which had bonding processing times of less than 50 ms, were judged as “good.”

[0133] In this way, the ultrasonic bonding evaluation method of embodiment 3 can determine that bonds that have a bonding processing time longer than the reference processing time are “bad”, even if it is assumed that the bonding points L(i) and R(j) are bonded well.

[0134] In the ultrasonic bond evaluation method according to the third embodiment, a bond pass / fail result can be obtained with high accuracy for the bonded portion by setting an appropriate reference processing time in step ST13.

[0135] In addition, the ultrasonic bond evaluation method of embodiment 3 obtains a plurality of bond pass / fail results corresponding to a plurality of bond points (bond points L(1) to L(52) and bond points R(1) to R(52)) in step ST13, and therefore can identify defective points in the plurality of bond points based on the plurality of bond pass / fail results.

[0136] In the example shown in FIG. 10, among the joints L(1) to L(52) of the aluminum lead wire 3L, the joints L(10) and L(30) can be identified as defective parts judged as "no."

[0137] In the ultrasonic bonding evaluation method of the third embodiment, the material to be bonded 13 is an aluminum lead wire 3 which is an electrode material used in solar cells, and the reference processing time is set based on the takt time of step ST22 which is a process for manufacturing the solar cell.

[0138] The ultrasonic bonding evaluation method of embodiment 3 sets a reference processing time based on the takt time in step ST22, so that a bonding point bonded with a bonding processing time that may affect the takt time can be determined to be defective.

[0139] <Fourth embodiment> The ultrasonic bonding evaluation method of the fourth embodiment, which is an ultrasonic bonding evaluation method of the present disclosure, evaluates ultrasonic vibration operation using the ultrasonic vibration bonding apparatus 102 of the second embodiment as an improved ultrasonic vibration bonding apparatus.

[0140] Fig. 11 is a flowchart showing the processing procedure of the ultrasonic bond evaluation method according to embodiment 4. Fig. 12 is a flowchart showing details of the setting processing of the reference processing time in step ST11 shown in Fig. 11. The processing contents of the ultrasonic bond evaluation method according to embodiment 4 will be described below.

[0141] Step ST10 is a step for setting a reference processing time, which is executed prior to steps ST11 to ST13. Hereinafter, the process for setting the reference processing time shown in step ST10 will be described with reference to FIG.

[0142] First, in step ST101, ultrasonic vibration is applied to a plurality of experimental joints, and the experimental joint processing time for each of the plurality of experimental joints is measured as a plurality of experimental joint processing times.

[0143] For convenience of explanation, the following describes a case where the solar cell substrate 4 shown in Fig. 7 is used as the experimental subject. In this case, the experimental joined materials are the aluminum lead wires 3L and 3R, and the multiple experimental joining points are the joining points L(1) to L(52) for the aluminum lead wire 3L and the joining points R(1) to R(52) for the aluminum lead wire 3R. The respective joining process times for the joining points L(1) to L(52) and the joining points R(1) to R(52) are the multiple experimental joining process times.

[0144] Thus, step ST101 is a step of performing an ultrasonic vibration operation using the ultrasonic vibration bonding device 102 to apply ultrasonic vibration to a plurality of experimental bonding points (L(i) and R(j)) of the aluminum lead wires 3 (3L, 3R), which are experimental bonding materials arranged on the solar cell substrate 4. As a result, the aluminum lead wire 3L is bonded to the electrode formation region 4a at the experimental bonding point (L(i)), and the aluminum lead wire 3R is bonded to the electrode formation region 4a at the experimental bonding point (R(j)).

[0145] Since the ultrasonic vibration bonding device 102 outputs processing time information TP when performing ultrasonic vibration operation, the experimental bonding processing time for each of the multiple experimental bonding points (L(i) and R(j)) can be easily measured by referring to the processing time information TP.

[0146] Thereafter, in step ST102, the experimental bonding processing time for each of the multiple experimental bonding points (L(i) and R(j)) is recognized as multiple experimental bonding processing times. Since processing time information TP is obtained for each experimental bonding point in ST101, the experimental bonding processing time during execution of the ultrasonic vibration operation for each of the multiple experimental bonding points (L(i) and R(j)) can be easily recognized as multiple experimental bonding processing times.

[0147] Next, in step ST103, the bonding strength of each of the plurality of experimental bonding points is measured as a plurality of experimental bonding strengths. The plurality of experimental bonding strengths can be measured by an existing technique.

[0148] Thereafter, in step ST104, a bond pass / fail result for each of the plurality of experimental joints is obtained as a plurality of experimental bond pass / fail results based on a comparison result between each of the plurality of experimental bond strengths and the reference bond strength.

[0149] 13 is an explanatory diagram showing, in table form, the experimental results during the process of setting the reference processing time in step ST10 of the fourth embodiment. In the figure, experimental joints No. 1 to 5 are shown. The joint position of No. 1 is the experimental joint R(10), the joint position of No. 2 is the experimental joint R(20), the joint position of No. 3 is the experimental joint L(10), the joint position of No. 4 is the experimental joint L(20), and the joint position of No. 5 is the experimental joint L(30). In addition, the output values, which are the output threshold value WX finally indicated by the output information SC at the experimental joints No. 1 to No. 5, were all 150 (W).

[0150] As shown in FIG. 13, the experimental bonding processing time for No. 1 was 30 ms, the experimental bonding processing time for No. 2 was 32 ms, the experimental bonding processing time for No. 3 was 60 ms, the experimental bonding processing time for No. 4 was 45 ms, and the experimental bonding processing time for No. 5 was 100 ms.

[0151] In the fourth embodiment, the reference bonding strength is set to 2 (N). As shown in Fig. 13, the experimental bonding strength of No. 1 was 4.84 (N), the experimental bonding strength of No. 2 was 5.11 (N), the experimental bonding strength of No. 3 was 1.52 (N), the experimental bonding strength of No. 4 was 2.12 (N), and the experimental bonding strength of No. 5 was 0.24 (N).

[0152] 13, the experimental bond strength of the experimental bonded portion L(i) tends to be weaker than that of the experimental bonded portion R(j), and the experimental bonding process time of the bonded portion L(i) tends to be longer than that of the bonded portion R(j). From this, it is inferred that there is a positive correlation between the experimental bond strength and the experimental bonding process time.

[0153] 13, the reference joint strength is set to 2 (N), and the experimental joints No. 3 and No. 5, which have experimental joint strengths of 1.52 (N) and 0.24 (N), respectively, which are smaller than 2 (N), are judged as "bad," and the experimental joints No. 1, No. 2, and No. 4 are judged as "good." In this way, in step ST104, pass / fail judgment results for No. 1 to No. 5 are obtained as multiple experimental joint pass / fail results.

[0154] Thereafter, in step ST105, a reference processing time corresponding to the reference bonding strength is determined based on the plurality of experimental bonding pass / fail results and the plurality of experimental bonding processing times. Here, the experimental bonding processing times No. 1 to No. 5 become the plurality of experimental bonding processing times.

[0155] Considering that there is a positive correlation between the experimental bonding strength and the experimental bonding processing time, the pass / fail judgment results of No. 1 to No. 5 are compared with the experimental bonding processing times of No. 1 to No. 5 to determine the reference processing time.

[0156] In the experimental results shown in Figure 13, the time period greater than 45 ms, which is the experimental bonding processing time of No. 4, and less than 60 ms, which is the experimental bonding processing time of No. 3, is a candidate for the reference processing time, and for example, 50 ms can be determined as the reference processing time.

[0157] In this way, the ultrasonic bonding evaluation method of embodiment 4 can set a standard processing time at which it can be assumed that the bonding points are well bonded in step ST10 through experiments in which ultrasonic vibration operations are performed on multiple experimental bonding points.

[0158] Steps ST11 to ST13, which are executed after step ST10, are executed for manufacturing a substrate equivalent to the solar cell substrate 4 that was the experimental subject. Note that steps ST11 to ST13 shown in Fig. 11 are substantially the same as steps ST11 to ST13 in the ultrasonic bonding evaluation method according to the third embodiment shown in Fig. 8, and therefore a description thereof will be omitted.

[0159] In the ultrasonic bonding evaluation method of embodiment 4, since the bonding pass / fail result is obtained in step ST13, by appropriately setting the reference processing time, as in embodiment 3, it is possible to obtain a highly accurate bonding pass / fail result for the experimental bonding points.

[0160] In addition, in the ultrasonic bonding evaluation method of embodiment 4, in step ST10, ultrasonic vibration is performed on a plurality of experimental bonding points, and a standard processing time corresponding to a standard bonding strength is set, so that bonding points that exceed the standard processing time can be inferred to have a bonding strength below the standard bonding strength and judged to be defective.

[0161] In addition, as in embodiment 3, the ultrasonic bonding evaluation method of embodiment 4 obtains multiple bonding pass / fail results corresponding to multiple experimental bonding points in step ST13, and therefore, it is possible to identify defective points in the multiple experimental bonding points based on the multiple bonding pass / fail results.

[0162] In the ultrasonic bonding evaluation method of embodiment 4, when repeatedly judging the pass / fail behavior of the aluminum lead wire 3 that is the (experimental) bonded material and the solar cell substrate 4 that has a common (experimental) bonding point (L(i), R(j)), the process of setting the reference processing time in step ST10 may be performed once, and thereafter the process of step ST10 may be omitted and only the processes of steps ST11 to ST13 may be performed.

[0163] <Other> In addition, within the scope of the present disclosure, it is possible to freely combine the respective embodiments, and to appropriately modify or omit the respective embodiments.

[0164] For example, in the first and second embodiments, the control unit 1 (1B) may be provided outside the ultrasonic oscillator 12 (12). Hereinafter, the control unit 1 provided outside is referred to as the "externally arranged control unit." The externally arranged control unit may be configured to control the output form of the oscillation signal S12 of the ultrasonic oscillator 12 and the pressurizing operation of the pressurizing cylinder 6. In this case, the externally arranged control unit outputs the oscillation signal S12 including the output information SC to the converter 11 via the ultrasonic oscillator 12.

[0165] In the ultrasonic bonding evaluation methods of the third and fourth embodiments, the evaluation method in ultrasonic vibration operation using the ultrasonic vibration bonding apparatus 102 of the second embodiment as the improved ultrasonic vibration bonding apparatus has been described, but the ultrasonic vibration bonding apparatus 101 may be used as the improved ultrasonic vibration bonding apparatus instead of the ultrasonic vibration bonding apparatus 102. In this case, however, it is necessary to measure and recognize the bonding processing time of the bonding portion by using a method other than using the processing time information TP.

[0166] In addition, in the third and fourth embodiments, the processing of step ST10 was performed on the experimental joining points of the experimental workpieces, but the reference processing time may also be obtained by using the joining points of the workpieces to be manufactured in the actual manufacturing process as the experimental joining points.

[0167] For example, when the same manufacturing process involving ultrasonic vibration operation on the workpieces is performed in the order of a first and a second manufacturing process, a reference processing time is set in step ST10 when the first manufacturing process is performed, and steps ST11 to ST13 are performed in the second manufacturing process using the reference processing time determined when the first manufacturing process is performed to determine pass / fail. [Explanation of symbols]

[0168] 1,1B Control section 2. Timer 3,3L,3R Aluminum lead wire 4. Solar Cell Substrate 4a Electrode formation area 6. Pressurizing cylinder 10 Ultrasonic vibration horn 11 Converter 12,12B Ultrasonic oscillator 13 Material to be joined 14 Substrate 20 Stages 101,102 Ultrasonic vibration bonding equipment L(1)~L(52), R(1)~R(52) joints

Claims

1. 1. A method for evaluating ultrasonic bonding in an ultrasonic vibration operation using an ultrasonic vibration bonding apparatus, comprising: (a) performing an ultrasonic vibration operation of applying ultrasonic vibration to a joining point of materials to be joined that are arranged on a substrate using the ultrasonic vibration bonding device, the ultrasonic vibration being generated based on an electrical signal including an electrical output value, and the ultrasonic vibration operation being performed at the joining point until the electrical output value reaches an output threshold value; (b) recognizing a processing time of the ultrasonic vibration operation on the joint as a bonding processing time; (c) obtaining a result of the quality of the joint of the joint based on a comparison result of the joint processing time and a reference processing time. Ultrasonic bonding evaluation method.

2. 2. The ultrasonic bonding evaluation method according to claim 1, the joint includes a plurality of joints; the bonding process time includes a plurality of bonding process times corresponding to the plurality of bonding locations, The step (a) (a-1) performing the ultrasonic vibration operation of applying the ultrasonic vibration to each of the plurality of joints, the ultrasonic vibration operation being performed at each of the plurality of joints until the electrical output value reaches the output threshold; The step (b) (b-1) including a step of recognizing the plurality of bonding process times; The step (c) (c-1) obtaining a plurality of bonding quality results for each of the plurality of bonding locations based on a comparison result between each of the plurality of bonding process times and the reference process time, Ultrasonic bonding evaluation method.

3. 3. The ultrasonic bonding evaluation method according to claim 2, The material to be joined is an electrode material used in a solar cell, the reference processing time is set based on a takt time of a process for producing the solar cell; Ultrasonic bonding evaluation method.

4. The ultrasonic bonding evaluation method according to claim 1 or 2, (d) a step of setting the reference processing time, the step being executed prior to the steps (a) to (c); The step (d) (d-1) performing an ultrasonic vibration operation by applying the ultrasonic vibration to a plurality of experimental bonding points of experimental workpieces arranged on a substrate using the ultrasonic vibration bonding device; (d-2) identifying a processing time of the ultrasonic vibration operation on the plurality of experimental bonding sites as a plurality of experimental bonding processing times; (d-3) measuring the bonding strength of each of the plurality of experimental bonding points as a plurality of experimental bonding strengths; (d-4) obtaining a plurality of experimental bond pass / fail results for each of the plurality of experimental bonded portions based on a comparison result between each of the plurality of experimental bond strengths and a reference bond strength; (d-5) determining the reference processing time based on the plurality of experimental bonding pass / fail results and the plurality of experimental bonding processing times; Ultrasonic bonding evaluation method.

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