JP6659857B2 - Wire bonding equipment - Google Patents

Description

  The present invention relates to a wire bonding apparatus for calibrating a pressing load of a bonding tool.

  2. Description of the Related Art A wire bonding apparatus that uses a bonding tool to press a wire against an electrode of a substrate or an electrode of an electronic component and connects the substrate and the electronic component or the electronic components with each other with a wire is often used. If the bonding apparatus is operated continuously for a long time, the pressing load may change over time due to the influence of the surrounding environment or the like. The pressing load has a large effect on the formation of an alloy of the wire and the electrode during bonding, and if the pressing load changes over time, the bonding quality may be degraded. For this reason, in the wire bonding apparatus, when the continuous operation is performed for a predetermined time, for example, about 1000 hours, the wire bonding apparatus is stopped, the pressing load is calibrated, and an appropriate pressing load is maintained.

  The calibration of the pressing load is performed, for example, in the following procedure. First, the load cell is mounted on the heat block, and then the bonding load is set with the tip of the bonding tool in contact with the load cell. Accordingly, the wire bonding apparatus operates so that the bonding tool presses the load cell with the set load. On the other hand, the actual pressing load of the bonding tool is detected by the load cell. When there is a difference between the actual pressing load detected by the load cell and the set pressing load, the applied current value of the motor driving the bonding tool is adjusted so that the actual pressing load becomes the set pressing load (for example, And Patent Document 1).

JP-A-10-284532

  In the calibration of the pressing load as described in Patent Document 1, since it is necessary to mount a load cell on the heat block of the wire bonding apparatus, the temperature of the heat block is reduced to a temperature at which the load cell can be used by turning off the heater of the heat block. We had to wait until it fell. Further, after the calibration of the pressing load is completed, it is necessary to turn on the heater of the heat block and wait until the temperature of the heat block reaches a temperature at which bonding can be performed. Further, when a plate-like heat piece for adjusting the height according to the type of the substrate, the electronic component or the like is mounted on the heat block, it is necessary to remove the heat piece when mounting the load cell. Therefore, it is necessary to readjust the bonding parameters after the calibration of the pressing load is completed. As described above, when the calibration interval of the pressing load is shortened to keep the pressing load as constant as possible to ensure the bonding quality, there is a problem that the productivity is reduced.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a bonding apparatus capable of calibrating a pressing load of a bonding tool with a simple configuration following a bonding operation.

The wire bonding apparatus of the present invention has a bonding tool that is driven vertically by a motor and presses a wire against an electrode, and has a plurality of pressing points corresponding to a plurality of current values having different magnitudes applied to the motor, comprising an elastic member displacement is generated according to the pressing load of the bonding tool, a displacement detector for detecting the displacement of the elastic member, and a control unit for adjusting the pressure load of the bonding tool, and the control unit, a plurality of the motor of the current value is sequentially applied sequentially pressing the respective pressing points of the elastic member by the bonding tool, sequentially detects each displacement of the respective pressing points of the elastic member by the displacement detecting means, the bonding tool on the basis of the displacement detected calibrating the pressure load, the plurality of pressing points, as displaced when the corresponding current value is applied falls within a predetermined range, that are arranged on top of the elastic member The features.

  In the wire bonding apparatus of the present invention, the calibration of the pressing load of the bonding tool performed by the control unit converts each detected displacement into each load applied to each pressing point, and a plurality of current values applied to the motor and each pressing. A characteristic curve indicating the relationship with the load applied to the point may be generated, and the value of the current applied to the motor may be adjusted based on the generated characteristic curve.

  In the wire bonding apparatus of the present invention, the elastic member may be a leaf spring.

  ADVANTAGE OF THE INVENTION The bonding apparatus of this invention can calibrate the press load of a bonding tool following a bonding operation with a simple structure.

It is a top view showing the wire bonding device of an embodiment of the present invention. 1 is a system diagram illustrating a system configuration of a wire bonding apparatus according to an embodiment of the present invention. It is the perspective view and top view which show the leaf spring assembly of the wire bonding apparatus of embodiment of this invention. FIG. 4 is an explanatory diagram illustrating a pressing point, a pressing load, and a displacement of the leaf spring assembly illustrated in FIG. 3. 5 is a flowchart illustrating an operation of a first pressing load calibration program executed by a control unit of the wire bonding apparatus according to the embodiment of the present invention. 5 is a flowchart illustrating an operation of a second pressing load calibration program executed by a control unit of the wire bonding apparatus according to the embodiment of the present invention. 7 is a characteristic curve of a motor applied current value and a load generated in the operation shown in FIG. It is a perspective view showing other leaf spring assemblies of a wire bonding device of this embodiment. It is a perspective view showing other leaf spring assemblies of a wire bonding device of this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a wire bonding apparatus 100 of the present embodiment includes a frame 10, an XY table 11 mounted on the frame 10, a bonding head 12 mounted on the XY table 11, and a bonding head 12. 12, an ultrasonic horn 14 attached to the tip of the bonding arm 13, a capillary 15 as a bonding tool attached to the tip of the ultrasonic horn 14, and an electronic component 19 such as a semiconductor die. , A guide rail 16 for guiding the substrate 18 in the X direction, a heat block 17, and a leaf spring assembly 20.

  As shown in FIG. 2, a motor 40 for driving the bonding arm 13 in the vertical direction (Z direction) is provided inside the bonding head 12. The motor 40 includes a stator 41 fixed to the bonding head 12 and a mover 42 that rotates around a rotation axis 45. The mover 42 is integrated with the rear part of the bonding arm 13. When the mover 42 rotates, the tip of the bonding arm 13 moves in the vertical direction (Z direction). A flange 14b of the ultrasonic horn 14 is fixed to a tip of the bonding arm 13 with a bolt 14c. In addition, a recess 13 a for accommodating the ultrasonic vibrator 14 a of the ultrasonic horn 14 is provided on a lower side surface of the tip portion of the bonding arm 13. A capillary 15 is attached to the tip of the ultrasonic horn 14. The heat block 17 is mounted on the frame 10 between the two guide rails 16, and the leaf spring assembly 20 is mounted on the frame 10 between the heat block 17 and the guide rail 16. I have. Further, a heater 17 a for heating the heat block 17 is attached to the heat block 17.

  The height of the upper surface of the leaf spring 31 of the leaf spring assembly 20 is the height of the upper surface of the electrode of the electronic component 19 when the substrate 18 is vacuum-sucked on the heat block 17 (one point in FIG. 2). (Indicated by a chain line 47). Further, the height of the rotation center 43 of the rotation shaft 45 of the mover 42 (indicated by the intersection of the alternate long and short dash line 47 and the alternate long and short dash line 46 in FIG. 2) is substantially the same as the height of the bonding surface. Therefore, when the mover 42 rotates, the tip of the capillary 15 moves up and down in a direction substantially perpendicular to the electrode surface of the electronic component 19 and the upper surface of the leaf spring 31.

  The stator 41 of the motor 40 is supplied with driving power from a power supply 49. The current value supplied to the stator 41 is detected by a current sensor 51, and the current value is adjusted by a motor driver 48. An angle sensor 52 for detecting the rotation angle φ of the mover 42 is attached to the rotation shaft 45 of the mover 42. Further, near the bonding head 12, a temperature sensor 53 for detecting a representative temperature of the wire bonding apparatus 100 is attached.

  The wire bonding apparatus 100 is a computer including a CPU 61 that internally performs calculations and signal processing, and a memory 62 that stores a program for operating the wire bonding apparatus 100 and data necessary for executing the program. A control unit 60 for controlling the operation is provided. The control unit 60 receives signals detected by the angle sensor 52, the current sensor 51, and the temperature sensor 53. The control unit 60 determines a current value to be supplied to the stator 41 of the motor 40, and outputs a current value command to the motor driver 48. The motor driver 48 adjusts a current value applied to the stator 41 based on a command input from the control unit 60. The control unit 60 is also connected to the XY table 11 shown in FIG. 1, and outputs a command for the position of the capillary 15 in the XY direction to the XY table 11. The XY table 11 adjusts the position in the XY direction of the capillary 15 to the position specified by the control unit 60.

  The CPU 61 of the control unit 60 stores the signals detected by the angle sensor 52, the current sensor 51, and the temperature sensor 53, the position signals of the electrodes of the electronic component 19 and the substrate 18 input from an imaging device (not shown), and the like in the memory 62 beforehand Based on the information such as the type of the electronic component 19 and the pitch of the electrodes, the bonding program stored in the memory 62 is executed to operate the motor 40 to operate the capillary 15 in the up-down direction and the XY table 11. Are moved in the X and Y directions to perform a bonding operation for connecting the electrodes of the electronic component 19 and the electrodes of the substrate 18 with wires.

  The control unit 60 stores a pressing load calibration program described later in the memory 62. The CPU 61 of the control unit 60 executes a pressing load calibration program stored in the memory 62 based on signals detected by the angle sensor 52, the current sensor 51, the temperature sensor 53, and applies a predetermined current to the motor 40. Then, the leaf spring 31 is pressed by the tip of the capillary 15, the displacement of the leaf spring 31 is detected, and the operation of calibrating the pressing load of the capillary 15 based on the detected displacement is executed.

  As shown in FIG. 3A, the leaf spring assembly 20 includes a base 21 having a rectangular flat plate shape, a support base 22 projecting above a distal end portion (a portion on the minus side in the X direction) of the base 21, and a base 21. It has a flange 26 provided on the lower surface (minus side in the Z direction) and a cantilever leaf spring 31 fixed to the upper surface (upper surface in the Z direction) of the support base 22 with bolts 25. The leaf spring 31 is a thin metal plate and protrudes from the upper surface of the support base 22 toward the minus side in the X direction. A notch 23 is provided in a portion of the support base 22 corresponding to the root side of the leaf spring 31 so that the leaf spring 31 can be bent and deformed downward. Further, the flange 26 is provided with a bolt hole 27 for fixing the leaf spring assembly 20 to the frame 10 with bolts.

  The displacement in the Z direction when the leaf spring 31 is pressed by the tip of the capillary 15 is proportional to the load. For this reason, for example, when the 5 g pressing point 32 is pressed with a load of 200 g, a displacement as much as 40 times that when pressed with a load of 5 g occurs. Conversely, even if the pressing point for 200 g is pressed with a load of 5 g, the displacement will be 1/40 that of pressing with a load of 200 g. For this reason, as shown in FIG. 3B, the leaf spring 31 of the present embodiment includes a tapered portion having a narrower width toward the tip (toward the minus side in the X direction) and a band-shaped portion having a constant width. The shape of the combination is such that the overall width becomes narrower toward the tip. As a result, a large displacement is generated with a small load toward the distal end, and a large load is required to generate the same displacement at the root.

  As shown in FIG. 3B, on the upper surface of the leaf spring 31, pressing points 32, 33, and 34 for pressing the tip of the capillary 15 as a bonding tool are marked. As for each pressing point, the pressing point 32 at the tip is a pressing point used when the pressing load of the capillary 15 is small, for example, about 5 g, and the pressing point 33 at the center is the pressing load of the capillary 15, for example. The pressing point used when the medium size is about 20 g, and the pressing point 34 on the root side is used when the pressing load of the capillary 15 is a large load of about 200 g, for example.

  With this configuration, as shown in FIG. 4A, the displacement Δ1 when pressing the foremost pressing point 32 with a small load W1 (for example, 5 g) is shown in FIG. 4B. As shown in FIG. 4C, the displacement Δ2 when the intermediate pressing point 33 is pressed with a medium load W2 (for example, 20 g), and the root pressing with a large load W3 (for example, 200 g) as shown in FIG. The displacement Δ3 when the point 34 is pressed has substantially the same magnitude. Therefore, by using the pressing point corresponding to the pressing load, the displacement can be made substantially constant or within a predetermined range, and the position of the tip of the capillary 15 when the pressing point is pressed is largely shifted from the bonding surface. That is, the relationship between the pressing load by the capillary 15 and the displacement can be accurately grasped.

<Operation of First Press Load Calibration Program>
The operation of the first pressing load calibration program executed by the CPU 61 of the control unit 60 of the wire bonding apparatus 100 described above will be described with reference to FIG.

  As shown in step S101 in FIG. 5, the control unit 60 outputs a command to start the wire bonding apparatus 100. The wire bonding apparatus 100 turns on the heater 17a of the heat block 17 to increase the temperature of the heat block 17 to a predetermined temperature. When the temperature of the heat block 17 reaches a predetermined temperature, the substrate 18 on which the electronic components 19 are attached is moved along the guide rail 16 to a position above the heat block 17 by a feed mechanism (not shown). When the substrate 18 comes on the heat block 17, the substrate 18 is vacuum-sucked on the heat block 17.

  Then, according to the bonding program stored in the memory 62, the wire bonding apparatus 100 moves the capillary 15 in the vertical direction, and moves the XY table 11 in the XY directions to connect the electrodes of the electronic component 19 and the electrodes of the substrate 18 with each other. Are connected by wires.

  When the bonding of the electrodes of all the electronic components 19 attached to the substrate 18 to the electrodes of the substrate 18 is completed, the wire bonding apparatus 100 breaks the vacuum of the heat block 17 and moves the substrate 18 along the guide rail 16. The heat block 17 is moved to a storage (not shown). By repeating such an operation, the electrodes of the electronic components 19 mounted on many substrates 18 are bonded to the electrodes of the substrate 18.

  At the beginning of the bonding, the heat of the heater 17a is not transferred to the entire wire bonding apparatus 100, so the representative temperature of the wire bonding apparatus 100 detected by the temperature sensor 53 has not reached the steady operation temperature. As shown in step S102 of FIG. 5, the control unit 60 waits until the representative temperature of the wire bonding apparatus 100 reaches the steady operation temperature. If it is determined in step S102 in FIG. 5 that the representative temperature of the wire bonding apparatus 100 has reached the steady operation temperature, the process proceeds to step S103 in FIG. 5, in which the bonding operation is temporarily stopped, the XY table 11 is operated, and the capillary 15 is operated. The position is moved by the leaf spring 31 above the pressing point 32 and is adjusted to the height of the height pressing point 32 at the tip of the capillary 15. Then, a predetermined current is applied to the motor 40. At this time, the heater 17a is kept on.

  The current value applied to the motor 40 is, for example, a current value that applies a load of about 5 g to the pressing point 32 of the leaf spring 31 as described with reference to FIG. This current value may be a current value determined in advance by a test in which the capillary 15 is pressed onto the load cell and the load detected by the load cell becomes 5 g.

  As described with reference to FIG. 4A, when the leaf spring 31 is displaced by Δ1, the distal end of the capillary 15 also moves by Δ1 in the negative Z direction. At this time, the bonding arm 13 rotates around the rotation axis 45 by a predetermined angle. The control unit 60 acquires the rotation angle φ of the bonding arm 13 from the signal of the angle sensor 52, converts the rotation angle φ into the displacement Δ1 of the tip of the capillary 15, that is, the displacement Δ1 of the leaf spring 31, and Is detected (step S104 in FIG. 5). Therefore, the angle sensor 52 constitutes a displacement detecting means for detecting the displacement Δ1 of the pressing point 32 of the leaf spring 31.

  The controller 60 stores the displacement Δ1 detected in step S104 of FIG. 5 in the memory 62 as a reference displacement Δ1S, as shown in step S105 of FIG.

  After the reference displacement Δ1S is stored in the memory 62, the control unit 60 resumes the bonding operation and proceeds to step S106 in FIG. 5, in which the wire bonding apparatus 100 is operated for a predetermined time, for example, 1000 hours. The bonding operation is performed until the calibration timing of the pressing load comes.

  When the control unit 60 determines that the predetermined time has elapsed and the timing of the calibration of the pressing load has come, the process proceeds to step S107 in FIG. 5, and the bonding operation is temporarily stopped and the heater is stopped as described in step S103. With the 17a kept on, the XY table 11 is operated to move the position of the capillary 15 above the pressing point 32 of the leaf spring 31 to match the height of the tip of the capillary 15 with the pressing point 32. Then, a predetermined current is applied to the motor 40. Then, as described above, the rotation angle φ of the bonding arm 13 is acquired from the signal of the angle sensor 52, and the rotation angle φ is converted into the displacement Δ1 of the leaf spring 31 to convert the displacement of the pressing point 32 of the leaf spring 31. Δ1 is detected (Step S108 in FIG. 5).

  Then, the control unit 60 proceeds to step S109 in FIG. 5 and calculates an absolute value d = | detected displacement Δ1−reference displacement Δ1S | of a difference between the previously set reference displacement Δ1S and the currently detected displacement Δ1. Proceeding to S110, it is determined whether the value exceeds a predetermined threshold. If d is equal to or less than the predetermined threshold value, it is determined that it is not necessary to calibrate the pressing load, and the process returns to step S106 in FIG. 5 to restart the bonding operation.

  On the other hand, when the absolute value d of the difference exceeds the predetermined threshold, the pressing load is deviated from the initial pressing load, it is determined that calibration is necessary, and the motor is controlled so that the absolute value d of the difference becomes small. Increase or decrease the applied current value. For example, when the detected displacement Δ1 is about 110% of the reference displacement Δ1S, the current value applied to the motor 40 may be reduced to (100/110). Conversely, when the detected displacement Δ1 is about 90% of the reference displacement Δ1S, the current value applied to the motor 40 may be increased to (100/90).

  Then, while the operation of the wire bonding apparatus 100 is continued, the control unit 60 repeats the operations of steps S106 to S112 in FIG. 5, and stops the operation of the program when the wire bonding apparatus 100 is stopped.

  As described above, the wire bonding apparatus 100 of the present embodiment presses the leaf spring 31 by the capillary 15 successively to the bonding operation, and adjusts the value of the current applied to the motor 40 based on the displacement of the leaf spring 31. With this simple method, the pressing load of the capillary 15 can be calibrated without stopping the heater 17a, so that the bonding load can be secured by keeping the pressing load of the capillary 15 as constant as possible while suppressing a decrease in productivity. can do.

<Operation of the second pressing load calibration program>
Next, the operation of the second pressing load calibration program executed by the CPU 61 of the wire bonding apparatus 100 of the present invention will be described with reference to FIG. In this operation, a characteristic curve indicating the relationship between the pressing load W and the motor applied current value i as shown in FIG. According to the required pressing load determined by the type and the like, the command value of the necessary motor applied current value i is output to the motor driver 48 with reference to this characteristic curve, and the bonding operation for applying the required pressing load is performed. This is to calibrate the pressing load in the simple wire bonding apparatus 100. The operation similar to that described with reference to FIG. 5 will be described briefly.

  As shown in step S201 of FIG. 6, when the control unit 60 outputs a command to start the wire bonding apparatus 100, the wire bonding apparatus 100 turns on the heater 17a of the heat block 17 and sets the temperature of the heat block 17 to a predetermined temperature. Raise to temperature. Then, when the temperature of the heat block 17 reaches a predetermined temperature, the substrate 18 having the electronic components 19 mounted on its surface is moved along the guide rail 16 to a position above the heat block 17 by a feed mechanism (not shown). When the substrate 18 comes on the heat block 17, the substrate 18 is vacuum-sucked on the heat block 17.

  Then, according to the bonding program stored in the memory 62, the wire bonding apparatus 100 moves the capillary 15 in the vertical direction, and moves the XY table 11 in the XY directions to connect the electrodes of the electronic component 19 and the electrodes of the substrate 18 with each other. Are connected by wires. The wire bonding apparatus 100 stores, in the memory 62, a characteristic curve of a motor applied current value i necessary for generating a pressing load W of the capillary 15 at the time of bonding as shown by a solid line a in FIG. . The initial characteristic curve indicated by the solid line a is a characteristic curve set in advance by a test or the like. The memory 62 stores information such as the type of the electronic component 19 and the diameter of the wire. The control unit 60 determines the pressing load W when pressing the wire against the electrode based on the information stored in the memory 62. Then, the control unit 60 outputs to the motor driver 48 a command value of the motor applied current value i applied to the motor 40 when pressing the wire based on the characteristic curve of the solid line a in FIG. The motor driver 48 adjusts the current value applied to the motor 40 so as to be a current value command. As described above, at the time of bonding, the pressing load W of the capillary 15 is controlled based on the characteristic curve indicated by the solid line a in FIG.

  When the bonding of the electrodes of all the electronic components 19 attached to the substrate 18 to the electrodes of the substrate 18 is completed, the wire bonding apparatus 100 breaks the vacuum of the heat block 17 and moves the substrate 18 along the guide rail 16. The heat block 17 is moved to a storage (not shown). By repeating such an operation, the electrodes of the electronic components 19 mounted on many substrates 18 are bonded to the electrodes of the substrate 18.

  As shown in step S202 in FIG. 6, the wire bonding apparatus 100 waits until the representative temperature of the wire bonding apparatus 100 detected by the temperature sensor 53 reaches a predetermined steady-state operating temperature, and when the representative temperature reaches the predetermined temperature. Then, the process proceeds to step S203 in FIG. 6, and waits until the representative temperature reaches the steady-state operation temperature until the operation is performed for a predetermined operation time such as 1000 hours. Then, after driving for a predetermined driving time, the process proceeds to step S204 in FIG.

  After proceeding to step S204 shown in FIG. 6, the controller 60 resets the counter N to 1. Here, N is the number of the pressing points 32, 33, 34 arranged on the leaf spring 31. In the following description, the pressing point 32 is a first pressing point 32 corresponding to N = 1, the pressing point 33 is a second pressing point 33 corresponding to N = 2, and the pressing point 34 is a second pressing point corresponding to N = 3. A description will be given as the three pressing points 34. The first pressing point 32 is a pressing point corresponding to pressing with a small pressing load W10 shown in FIG. 7, for example, about 5 g, and the second pressing point 33 is a medium pressing load W20 shown in FIG. For example, the third pressing point 34 is a pressing point corresponding to pressing with about 20 g, and the third pressing point 34 is a pressing point corresponding to pressing with a large pressing load W30 shown in FIG. 7, for example, about 200 g. . The motor applied current value i10 shown in FIG. 7 is a current value applied to the motor 40 when the pressing load W10 is generated, and the motor applied current value i20 is applied to the motor 40 when the pressing load W20 is generated. The motor applied current value i30 is a current value applied to the motor 40 when the pressing load W30 is generated.

  When N is set to 1 in step S204 of FIG. 6, the control unit 60 proceeds to step S205 of FIG. 6, and sets the first pressing point 32 corresponding to N = 1 to the first pressing point 32. The motor application current value i10 shown in FIG. 7 is applied to the motor 40 so as to be pressed by the pressing load W10. Then, the process proceeds to step S207, where the rotation angle φ of the bonding arm 13 is acquired from the signal of the angle sensor 52, and the rotation angle φ is converted into the displacement Δ11 of the first pressing point 32, and the displacement Δ11 of the first pressing point 32 is calculated. It is detected (step S208 in FIG. 6). Since the displacement Δ11 of the first pressing point 32 and the pressing load applied to the first pressing point 32 are in a proportional relationship, the control unit 60 determines the relationship between the displacement of the first pressing point 32 and the pressing load in the detected displacement Δ11. Is multiplied by a proportional constant K1 to convert the displacement Δ11 into a pressing load W11 related to the first pressing point 32. After converting the displacement Δ11 into the pressing load W11, the control unit 60 stores the pressing load W11 in the memory 62.

  After storing the pressing load W11 in the memory 62, the control unit 60 proceeds to step S209 in FIG. 6, and N is the final value of Nend (in the embodiment, the pressing points are 32, 33, and 34, so Nend is Determine if 3) is true. If N is not 3, N is incremented by 1 in step S210 in FIG. 6 (in this case, N becomes 2), and the process returns to step S205.

  Then, as described above, the motor 40 applies the motor applied current value i20 shown in FIG. 7 so that the second pressing point 33 corresponding to N = 2 is pressed by the pressing load W20 corresponding to the second pressing point 33. Apply. Then, the process proceeds to step S207 to detect the displacement Δ21 of the second pressing point 33. Then, the control unit 60 multiplies the detected displacement Δ21 by a proportional constant K2 indicating the relationship between the displacement of the second pressing point 33 and the pressing load, and converts the displacement Δ21 into a pressing load W21 related to the second pressing point 33. After converting the displacement Δ21 into the pressing load W21, the control unit 60 stores the pressing load W21 in the memory 62. The control unit 60 determines whether or not N is the final value Nend (Nend is 3 in the embodiment) in the step of FIG. If N is not 3, N is incremented by 1 in step S210 in FIG. 6 (N becomes 3 in this case), and the process returns to step S205.

  Then, as described above, the motor 40 applies the motor applied current value i30 shown in FIG. 7 so that the third pressing point 34 corresponding to N = 3 is pressed by the pressing load W30 corresponding to the second pressing point 34. Apply. Then, the process proceeds to step S207 to detect the displacement Δ31 of the third pressing point 34. Then, the control unit 60 multiplies the detected displacement Δ31 by a proportional constant K3 indicating the relationship between the displacement of the third pressing point 34 and the pressing load, and converts the displacement Δ31 into a pressing load W31 related to the second pressing point 34. After converting the displacement Δ31 into the pressing load W31, the control unit 60 stores the pressing load W31 in the memory 62. The control unit 60 determines whether or not N is the final value Nend (Nend is 3 in the embodiment) in the step of FIG. Now, since N = 3, the control unit 60 determines YES in step S209 in FIG. 6 and proceeds to step S211 in FIG.

  As described with reference to FIGS. 4A to 4C, the pressing points 32, 33, and 34 of the leaf spring 31 of the present embodiment correspond to the pressing points 32, 33, and 34, respectively. The displacements Δ10, Δ20, and Δ30 when the corresponding pressing loads W10 (for example, 5 g), W20 (for example, 20 g), and W30 (for example, 200 g) are applied are arranged to have substantially the same value. For this reason, the proportional constants K1, K2, and K3 indicating the relationship between the displacement of each of the pressing points 32, 33, and 34 and the pressing load on each of the pressing points 32, 33, and 34 are not the same, and K1 <K2 <K3. I have. As described above, when W10 is 5 g, W20 is 20 g, and W30 is 200 g, K2 is four times k1 and K3 is 40 times K1. The values of K1 to K3 are set in advance based on the values of W10, W20, and W30 and the positions of the pressing points 32 to 34 of the leaf spring 31, and are stored in the memory 62.

  The control unit 60 repeatedly executes steps S205 to S208 of FIG. 6 N times (three times in the above case), and applies a pressing load when the motor applied current values i10, i20, i30 are applied to the motor 40, W11, W21 and W31 are detected. For example, due to a change with time, the detected W11, W21, and W31 are larger than the initial W10, W20, and W30, as shown by the one-dot chain line b in FIG. Therefore, the control unit 60 determines from the results of steps S205 to S208 the new characteristic that determines the command value of the motor applied current value i applied to the motor 40 when pressing the wire, as shown by the dashed line b in FIG. Generate a curve. The characteristic curve may be generated by linearly complementing the three points (i10, W11), (i20, W21), and (i30, W31), or a regression curve is obtained from the three points, and the characteristic curve is calculated from the regression curve. May be set.

  After generating a new characteristic curve as shown by the one-dot chain line b in FIG. 7, the control unit 60 proceeds to step S212 in FIG. 6, and calculates a characteristic curve for adjusting the pressing load W when the capillary 15 presses the wire, The bonding operation is restarted with the new characteristic curve generated in step S212. In the restarted bonding operation, as shown in FIG. 7, when the pressing load W10 is to be applied, the control unit 60 issues a command to set the motor applied current value i to i11 smaller than i10. Output to The motor driver 48 adjusts the applied current value i of the motor to i11 based on this command.

  Then, while the operation of the wire bonding apparatus 100 is continued, the control unit 60 repeats the operations of steps S203 to S213 in FIG. 6, and stops the operation of the program when the wire bonding apparatus 100 is stopped.

  As described above, the wire bonding apparatus 100 according to the present embodiment can apply a plurality of current values i10, i20, and i30 to the motor 40 sequentially without stopping the heater 17a, following the bonding operation. 31 are sequentially pressed by the capillary 15 and the loads W11 applied to the pressing points 32, 33, 34 from the displacements Δ11, Δ21, Δ31 of the pressing points 32, 33, 34, respectively. , W12, and W13, and generates a new characteristic curve for determining the command value of the motor application current value i applied to the motor 40 when pressing the wire, and based on the newly generated characteristic curve, Adjust the value of the applied current. As a result, the wire bonding apparatus 100 of the present embodiment can maintain the pressing load of the capillary 15 as constant as possible while securing the bonding quality while suppressing the decrease in productivity.

  In the present embodiment, as described with reference to FIG. 3A, the leaf spring 31 has a tapered portion whose width decreases toward the tip (toward the minus side in the X direction) and a band-like portion having a constant width. In the above description, the leaf spring 31 has a shape such that the overall width becomes narrower toward the tip, but the leaf spring 31 may be replaced with two supports as shown in FIG. The plate spring 71 may be fixed at both ends to the base 22. Also in this case, a plurality of pressing points 72, 73, 74 may be provided on the upper surface of the leaf spring 71. In addition, as shown in FIG. 9, instead of increasing the width toward the root, the thickness is increased toward the root, and pressing points 76, 77, 78 are provided thereon. A simple leaf spring 75 may be used.

  Even when the leaf springs 71 and 75 as shown in FIGS. 8 and 9 are used, the same effects as described above can be obtained.

  10 frame, 11 table, 12 bonding head, 13 bonding arm, 13a recess, 14 ultrasonic horn, 14a ultrasonic transducer, 14b flange, 14c bolt, 15 capillary, 16 guide rail, 17 heat block, 17a heater, 18 substrate , 19 electronic components, 20 assembly, 21 base, 22 support base, 23 notch, 25 bolt, 26 flange, 27 bolt hole, 32-34, 72-74, 76-78 pressing point, 40 motor, 41 stator , 42 mover, 43 rotation center, 45 rotation axis, 46, 47 chain line, 48 motor driver, 49 power supply, 51 current sensor, 52 angle sensor, 53 temperature sensor, 60 control unit, 61 CPU, 62 memory, 100 wires Bonding equipment.

Claims (3)

A wire bonding apparatus,
A bonding tool that is driven vertically by a motor and presses the wire against the electrode;
An elastic member having a plurality of pressing points corresponding to a plurality of current values having different magnitudes applied to the motor, and a displacement occurring according to a pressing load of the bonding tool;
Displacement detection means for detecting the displacement of the elastic member,
A control unit for adjusting the pressing load of the bonding tool,
The control unit includes:
A plurality of current values are sequentially applied to the motor, and each pressing point of the elastic member is sequentially pressed by the bonding tool,
The displacement detecting means sequentially detects each displacement of each of the pressing points of the elastic member,
Calibrate the pressing load of the bonding tool based on each detected displacement ,
The plurality of pressing points are arranged on the elastic member so that displacement when a corresponding current value is applied is within a predetermined range,
A wire bonding apparatus characterized by the above-mentioned . The wire bonding apparatus according to claim 1 ,
Calibration of the pressing load of the bonding tool performed by the control unit,
Convert each detected displacement to each load applied to each pressing point,
Generate a characteristic curve showing the relationship between the plurality of current values applied to the motor and the load applied to each pressing point,
A wire bonding apparatus that adjusts a current value applied to the motor based on the generated characteristic curve. The wire bonding apparatus according to claim 1 or 2 ,
The wire bonding device, wherein the elastic member is a leaf spring.

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