Wire bonding apparatus, control device, and control method

Abstract

The present invention aims to provide a wire bonding apparatus, control device, and control method that can determine the engagement quality of a bump at an earlier time. The wire bonding apparatus of one embodiment includes a bonding tool that sequentially dispenses wires, a drive unit that drives the bonding tool, and a control unit that controls the bonding tool and the drive unit. The control unit performs a bonding step, namely: bringing a ball formed at the leading end of the wire into contact with a first bonding point, deforming the ball into a bump, and engaging the bump with the first bonding point. The control unit then performs a lowering step, namely: raising the bonding tool holding the wire connected to the bump, changing its horizontal position, and then lowering the bonding tool towards the first bonding point. Based on a specified detection value detected during the lowering step, the control unit determines whether the bump is properly engaged with the first bonding point.

Description

Technical Field

[0001] The present invention relates to a wire bonding device, a control device, and a control method. Prior Technology

[0002] In the manufacturing process of semiconductor devices, most steps involve the use of wire bonding equipment. This equipment performs tasks such as bump formation and wire bonding. For wire bonding equipment, there is a need for technology that can determine the quality of bump bonding at an earlier stage. [Previous Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2013-225637 Summary of the Invention

[0004] [The problem the invention aims to solve] The problem to be solved by the present invention is to provide a wire bonding device, control device and control method that can determine the goodness of bump engagement at an earlier time. [Technical means to solve the problem]

[0005] The wire bonding device in this embodiment includes a bonding tool that sequentially dispenses wires, a drive unit that drives the bonding tool, and a control unit that controls the bonding tool and the drive unit. The control unit performs a bonding step, namely: bringing a ball formed at the leading end of the wire into contact with a first bonding point, deforming the ball into a protrusion, and engaging the protrusion with the first bonding point. The control unit then performs a lowering step, namely: raising the bonding tool, which holds the wire connected to the protrusion, changing its horizontal position, and then lowering the bonding tool towards the first bonding point. Based on a specified detection value detected during the lowering step, the control unit determines whether the protrusion is properly engaged with the first bonding point. Simple Explanation of the Diagram

[0006] Figure 1 is a schematic diagram showing the implementation of the wire bonding device. Figure 2 is a schematic diagram showing a portion of the wire bonding device in a schematic implementation. Figures 3(a) to 3(c) are schematic diagrams showing one example of the wire splicing steps. Figure 4 is a schematic diagram showing one example of the bump joining process. Figure 5 is a schematic diagram showing the variation of the Z position of the joining tool. Figure 6(a) is a schematic diagram showing the condition of the bump when the engagement is good. Figure 6(b) is a schematic diagram showing the condition of the bump when the engagement is poor. Figure 7 is a schematic diagram showing another example of the bump engagement step. Figure 8 is a schematic diagram showing the variation of the Z position of the joining tool. Figure 9 is a schematic diagram showing one example of the bump joining process. Figure 10 is a schematic diagram showing the variation of the load on the mating tool. Figure 11 is a schematic diagram showing the change of the Z position of the joining tool. Figure 12 is a schematic diagram showing the hardware configuration. Implementation

[0007] The following description, with reference to the drawings, outlines various embodiments of the present invention. The drawings are conceptual or schematic; the thickness and width relationships of the parts, and the size proportions between parts, may not be identical to the actual object. Furthermore, even when showing the same parts, their dimensions or proportions may differ depending on the drawings. In this specification and the drawings, the same symbols are used for elements already described, and detailed descriptions are appropriately omitted.

[0008] This invention relates to a wire bonding device, a control device for controlling the device, and a control method for the device. For example, the wire bonding device is used in the manufacturing process of a semiconductor device to connect the electrodes, i.e., pads, of a semiconductor wafer to the electrodes, i.e., leads, of a lead frame using thin metal wires, i.e., conductive wires.

[0009] (First Implementation) Figure 1 is a schematic diagram showing the implementation of the wire bonding device. As shown in Figure 1, the wire bonding device 100 of the embodiment includes a bonding head 10, a position detection unit 10a, an XY stage 20, a bonding stage 30, a load sensor 40, a camera device 50, and a control unit 60.

[0010] The connector 10 includes a connector tool 11, an ultrasonic horn 12, a connector arm 13, and a drive unit 14.

[0011] The joining tool 11 successively releases the wires 3, which become the joining material. The joining tool 11 is, for example, a joining capillary. The wires 3 are, for example, aluminum wire, gold wire, silver wire, or copper wire. The joining tool 11 brings the wires 3 into contact with the part 2 to be joined of the workpiece 1 placed on the joining platform 30, and applies a load to the part 2 to be joined. In this embodiment, the part 2 to be joined is either the first joining point P1 or the second joining point P2, which will be described later.

[0012] The position detection unit 10a detects the Z-direction position of the engagement tool 11. For example, if the origin is defined at a specified position, the position detection unit 10a detects the vertical position of the engagement tool 11 from that origin. The position detection unit 10a is communicatively connected to the control unit 60.

[0013] The ultrasonic horn 12 generates ultrasonic vibrations. The ultrasonic horn 12 includes an ultrasonic transducer that generates ultrasonic vibrations. The ultrasonic horn 12 supports a joining tool 11. The ultrasonic vibrations generated by the ultrasonic horn 12 are transmitted to the wire 3 via the joining tool 11. With the wire 3 in contact with the part to be joined 2, the ultrasonic vibrations are transmitted to the wire 3, thereby joining the wire 3 and the part to be joined 2. The ultrasonic horn 12 is electrically connected to the control unit 60.

[0014] The engagement arm 13 supports the ultrasonic horn 12. That is, the engagement arm 13 supports the engagement tool 11 via the ultrasonic horn 12. The engagement arm 13 is rotatably arranged with respect to the shaft portion 13a.

[0015] The drive unit 14 drives the engagement arm 13 in the Z direction with the shaft 13a as the center. The drive unit 14 is, for example, a linear motor. By moving the engagement arm 13 in the Z direction, the engagement tool 11 and the ultrasonic horn 12 supported by the engagement arm 13 move in the Z direction. By moving the engagement tool 11 in the Z direction, the wire 3 can come into contact with the first engagement point P1 or the second engagement point P2 (described later), and a load can be applied from the engagement tool 11. The drive unit 14 is communicatively connected to the control unit 60.

[0016] In this specification, the direction connecting the joining tool 11 and the workpiece 1 is defined as the Z direction. The direction orthogonal to the Z direction is defined as the X direction. The direction orthogonal to both the Z and X directions is defined as the Y direction. For example, the Z direction is parallel to the vertical direction. The X and Y directions are parallel to the horizontal plane. Furthermore, here, the direction from the joining tool 11 toward the workpiece 1 is referred to as "down", and the direction opposite to down is referred to as "up".

[0017] The coupling head 10 is mounted on the XY stage 20. The XY stage 20 is movable in both the X and Y directions. As the XY stage 20 moves in both the X and Y directions, the coupling head 10 also moves in both the X and Y directions. In other words, the XY stage 20 functions as a positioning mechanism for positioning the coupling tool 11 mounted on the coupling head 10 in both the X and Y directions. The XY stage 20 is communicatively connected to the control unit 60.

[0018] The bonding stage 30 supports the object to which the wires are bonded, namely the workpiece 1. The bonding stage 30 supports the workpiece 1, for example, by adsorbing it. The workpiece 1 is a semiconductor wafer such as an IC chip or a substrate.

[0019] The load sensor 40 continuously detects the load applied from the joined portion 2 of the workpiece 1 to the joining tool 11. The load sensor 40 may include, for example, a strain gauge. In the illustrated example, the load sensor 40 is mounted on the joining arm 13. The load sensor 40 is communicatively connected to the control unit 60. The load sensor 40 outputs the detected load data to the control unit 60.

[0020] The camera device 50 captures images of the sphere formed at the front end of the joining tool 11. Parameters of the sphere can be calculated based on the images acquired by the camera device 50.

[0021] The control unit 60 controls the operation of the bonding tool 11, the ultrasonic horn 12, the drive unit 14, and the XY stage 20. For example, the control unit 60 controls the sequential release of the wires from the bonding tool 11 and the wire supply speed. The control unit 60 also controls the output of the ultrasonic vibrations generated by the ultrasonic horn 12.

[0022] Furthermore, the control unit 60 can move the engagement tool 11 by actuating the drive unit 14. More specifically, the control unit 60 can control the Z-direction position of the engagement tool 11 by controlling the drive unit 14 to drive the engagement arm 13 in the Z-direction. In this way, the control unit 60 can control the magnitude of the load applied by the engagement tool 11 to the joined portion 2.

[0023] The position detection unit 10a acquires the position of the engagement tool 11 driven by the drive unit 14 in the Z direction. The position detection unit 10a may also be included within the control unit 60. For example, the position detection unit 10a includes an encoder. When the motor of the drive unit 14 is activated, the position detection unit 10a detects the rotation direction and rotation position of the motor. Based on the detected rotation direction and position, the position detection unit 10a calculates the position of the engagement tool 11 in the Z direction.

[0024] The control unit 60 can move the XY stage 20 to move the joining tool 11. More specifically, by controlling the XY stage 20, the control unit 60 drives the joining head 10 in the X and Y directions, thereby controlling the position of the joining tool 11 in the X and Y directions.

[0025] Figure 2 is a schematic diagram showing a portion of the wire bonding device in a schematic implementation. As shown in Figure 2, a protrusion 2a is formed on the joint portion 2 of the workpiece 1, and the wire 3 is joined to the protrusion 2a. The wire joining device 100 performs the formation of the protrusion 2a and the joining of the wire 3 to the protrusion 2a. For example, when the wire joining device 100 presses the wire 3, which is successively released from the joining tool 11, against the joint portion 2, ultrasonic vibration is generated by the ultrasonic horn 12, thereby joining the wire 3 to the joint portion 2.

[0026] Next, a series of steps for joining wires 3 will be described. Figures 3(a) to 3(c) are schematic diagrams showing an example of the wire joining steps. As shown in Figures 3(a) to 3(c), the wire bonding step includes three steps: a bump bonding step (Figure 3(a)), a first bonding step (Figure 3(b)), and a second bonding step (Figure 3(c)). In the illustrated example, a wafer C is disposed on a substrate BA. A first bonding point P1 is present on the wafer C, and a second bonding point P2 is present on the substrate BA. The substrate BA on which the wafer C is disposed is an example of a workpiece 1. The first bonding point P1 and the second bonding point P2 are examples of the parts 2 to be bonded. Bumps B1 and B2 are formed at the first bonding point P1 and the second bonding point P2, and the wire 3 is bonded to these bumps.

[0027] First, as shown in Figure 3(a), a bump bonding step is performed to form a bump B1 at the first bonding point P1. Specifically, the bonding tool 11 moves above the first bonding point P1 of the wafer C. A wire 3 is inserted into the bonding tool 11, and a ball is pre-formed at the leading end of the wire 3. For example, by applying a voltage to the wire, a discharge is generated at the leading end of the wire, causing the leading end of the wire to melt. The molten metal becomes spherical due to surface tension and solidifies, thereby forming a ball. The bonding tool 11 descends towards the first bonding point P1, and the ball at the leading end of the wire 3 contacts the first bonding point P1. Under a load applied to the wire 3, ultrasound is applied to the bonding tool 11. Thereby, the ball at the leading end of the wire 3 is deformed into a bump B1 on the wafer C, and the bump B1 is bonded to the first bonding point P1. Subsequently, the wire 3 is cut by ultrasound, leaving the bump B1 on the wafer C. And, the bonding tool 11 moves from above the first bonding point P1 to above the second bonding point P2.

[0028] After forming bump B1, as shown in Figure 3(b), the first bonding step is performed. A ball is pre-formed at the leading end of the conductor 3. The bonding tool 11 descends to the second bonding point P2, and the ball at the leading end of the conductor 3 contacts the second bonding point P2. Under a load applied to the conductor 3, ultrasonic waves are applied to the bonding tool 11. Thereby, the ball at the leading end of the conductor 3 is deformed into bump B2 on the substrate BA, and bump B2 is bonded to the second bonding point P2. After forming bump B2, the conductor 3 is not cut, and the conductor 3 is maintained in a state of connection with bump B2.

[0029] After forming bump B2, as shown in Figure 3(c), the second bonding step is performed. With bump B2 connected to wire 3, the bonding tool 11 moves upward a specified distance. Then, without bending wire 3, the bonding tool 11 moves from above the second bonding point P2 towards the first bonding point P1. Wire 3 is bonded to bump B1 on the wafer C. Furthermore, wire 3 is cut by ultrasonic vibration, bonding wire 3 to the wafer C and the substrate BA. The above sequence is an example of wire bonding.

[0030] Not limited to the example shown, the first bonding point can also be located on the substrate BA and the second bonding point can be located on the wafer C. In this case, after forming bump B1 on the substrate BA, bump B2 is formed on the wafer C, and the wire 3 is bonded from bump B2 to bump B1.

[0031] Next, the bump engagement process will be described in more detail. Figure 4 is a schematic diagram showing one example of the bump engagement process. As shown in Figure 4, the bump joining step includes a search step R1, a joining step R2, a reversal step R3, a descent step R4, a tail forming step R5, a tail cutting step R6, and a flashing step R7.

[0032] In the search step R1, the ball BO formed at the leading end of the wire 3 inserted into the bonding tool 11 is brought into contact with the surface of the wafer C. In the bonding step R2, a load and ultrasonic vibration are applied to the ball BO to flatten it and bond it to the surface of the wafer C. In the reversal step R3, the bonding tool 11 is raised a specified distance, and its position in the horizontal direction is changed. In the descent step R4, the height of the bump B1 is determined by lowering the bonding tool 11. In the reversal step R3 and the descent step R4, the connection between the wire and the bump remains unchanged. In the tail formation step R5, the bonding tool 11 is raised to a specified position to form a tail. In the tail cutting step R6, while the bonding tool 11 is raised, ultrasonic vibration is applied to cut the tail and the bump B1. Herein, the bump B1 is formed on the wafer C. In the subsequent flashing step R7, the leading end of the wire 3 is melted by the flashing generated at the leading end of the wire 3, forming a ball at the leading end of the wire 3.

[0033] Furthermore, Figure 4 shows the vibration state of the ultrasonic vibration (US) and the detection state of the Z position of the joining tool 11 in steps R1 to R7. In Figure 4, h1 represents the Z-direction position when the joining tool 11 descends to its maximum in the joining step R2. For example, in the joining step R2, the joining tool 11 descends until the joining tool 11 detects a specified load. Alternatively, the joining tool 11 descends until its descent speed becomes below a specified value. h2 represents the Z position when the joining tool 11 is descended to the point where the specified load is applied to the joining tool 11 in the descent step R4, or when the joining tool 11 is descended until its descent speed becomes below a specified value.

[0034] During the bump bonding step, the control unit 60 determines whether bump B1 and wafer C are properly bonded. The determination of whether bump B1 is properly bonded is made using Z-positions h1 and h2 as shown in Figure 4. Proper bonding of bump B1 means that bump B1 adheres to wafer C with sufficient bonding strength. Poor bonding of bump B1 means that the bonding strength between bump B1 and wafer C is insufficient. For example, in the case of poor bonding of bump B1, bump B1 is prone to peeling off from the surface of wafer C1.

[0035] The specific method for determining whether something is good or bad is explained. Figure 5 is a schematic diagram showing the change in the Z position of the joining tool. In Figure 5, the horizontal axis represents time, and the vertical axis represents the Z-position of the engagement tool 11. The solid line represents the change in Z-position when the bumps are well engaged. The dashed line represents the change in Z-position when the bumps are poorly engaged.

[0036] In the example shown in Figure 5, when the engagement of bump B1 is good, the engagement tool 11 descends to position Z21 in descent step R4. When the engagement of bump B1 is poor, the engagement tool 11 descends to position Z22 in descent step R4. The engagement tool 11 descends until the specified load is detected. That is, the inventors of this invention discovered that the Z position of the engagement tool 11 that detects the specified load when the engagement is poor is located lower than the Z position of the engagement tool 11 that detects the specified load when the engagement is good. It is believed that this difference in Z position is due to the difference between the state of bump B1 in descent step R4 when the engagement is good and the state of bump B1 in descent step R4 when the engagement is poor.

[0037] Alternatively, the joining tool 11 can be lowered at a certain speed, and the descent speed can be detected. When the output of the drive unit 14 is stable during the descent of the joining tool 11, if the joining tool 11 contacts the protrusion B1, the descent speed of the joining tool 11 decreases. During the descent step, the control unit 60 obtains the Z position of the joining tool 11 when the change in the descent speed of the joining tool 11 is below a specified value. When the Z position is obtained based on the descent speed, the Z position changes depending on whether the engagement is good or bad. It is believed that the difference in the Z position is also due to the difference between the state of the protrusion B1 in the descent step R4 when the engagement is good and the state of the protrusion B1 in the descent step R4 when the engagement is bad.

[0038] Figure 6(a) is a schematic diagram showing the condition of the bump when the engagement is good. Figure 6(b) is a schematic diagram showing the condition of the bump when the engagement is poor. As shown in Figure 6(a), in the reversal step R3 following the bonding step R2, the bonding tool 11 rises and then moves a predetermined distance in a predetermined direction. For example, the bonding tool 11 moves a predetermined distance in the X direction. The direction of movement of the bonding tool 11 can also be tilted relative to the horizontal plane. When the bonding is successful, in the reversal step R3, the position of the bump B1 bonded to the wafer C remains unchanged regardless of how the bonding tool 11 moves in the X direction. In the subsequent descent step R4, the bonding tool 11 descends, and the lower end of the bonding tool 11 contacts the interface between the bump B1 and the wire 3. At this time, a load is applied to the bonding tool 11. The descent of the bonding tool 11 stops when the load sensor 40 detects a specified load. Alternatively, if a load is applied to the bonding tool 11, the descent speed of the bonding tool 11 decreases. If the descent speed is lower than a specified value, the drive unit 14 stops the descent of the bonding tool 11.

[0039] On the other hand, in the case of poor bonding, bump B1 is easily peeled off from wafer C. Therefore, as shown in FIG6(b), it is assumed that the position of bump B1 changes according to the movement of bonding tool 11 in the X direction during the reversal step R3. Subsequently, in the descent step R4, when bonding tool 11 descends, the lower end of bonding tool 11 contacts the side of bump B1, rather than the interface between bump B1 and wire 3. If bonding tool 11 contacts the side of bump B1, a load is applied to bonding tool 11. The descent of bonding tool 11 stops based on either the load on bonding tool 11 or the descent speed of bonding tool 11. Therefore, the Z position where bonding tool 11 stops is a lower position than the case where bonding tool 11 contacts the interface between bump B1 and wire 3.

[0040] The control unit 60 determines whether the engagement of the protrusion B1 is good or bad by utilizing the change in Z position corresponding to whether the engagement is good or bad. Specifically, the control unit 60 calculates the difference between the Z position h1 detected in the engagement step R2 and the Z position (h21 or h22) detected in the descent step R4. As shown in Figure 5, the difference between Z position h1 and Z position h22 is less than the difference between Z position h1 and Z position h21. The control unit 60 compares the calculated difference with a preset threshold value. The threshold value is set to be greater than the difference between Z position h1 and Z position h22 and less than the difference between Z position h1 and Z position h21. When the difference is above the threshold value, the control unit 60 determines that the engagement of the protrusion B1 is good. When the difference does not reach the threshold value, the control unit 60 determines that the engagement of the protrusion B1 is bad.

[0041] When a defective engagement of bump B1 is detected, the control unit 60 stops the wire bonding step. The specific timing of the stop is arbitrary. For example, the control unit 60 may immediately stop the wire bonding step upon detecting a defective engagement of bump B1. Alternatively, the control unit 60 may stop the wire bonding step after reaching the tail cutting step R6. In either case, the subsequent first bonding step is not executed. When a defective engagement of bump B1 is detected, the control unit 60 executes the subsequent first bonding step and second bonding step.

[0042] Explain the advantages of the first implementation. If the bumps do not mesh properly, they are prone to peeling off. This can result in poor conductivity in the workpiece. Therefore, it is desirable to determine the quality of the mesh after the bumps are joined. As a reference example, the following two methods are considered to determine the quality of the mesh.

[0043] In the first method, when the bumps are joined, the resistance between the bump and the workpiece, or the electrostatic capacitance of the workpiece, is measured. If the bumps are joined well, a change in resistance or electrostatic capacitance will occur. This change can be used to determine whether the bumps are joined well or not.

[0044] In the second method, the Z-position of the bonding tool used in the second bonding step is employed. During the second bonding step, if the bumps are well bonded and remain on the wafer surface, the conductors contact the bumps. If the bumps are not sufficiently bonded and do not remain on the wafer surface, the conductors contact the wafer surface. That is, the Z-position of the bonding tool in the second bonding step changes depending on whether the bumps are well bonded. Therefore, the quality of bump bonding can be determined by the Z-position of the bonding tool in the second bonding step.

[0045] However, in the first method, if the workpiece is not conductive or has a small electrostatic capacitance, it is impossible to determine whether the bump connection is good or bad. In the second method, the connection is determined when the conductors are joined after the bumps are formed. In cases of poor connection, the bump connection is visually inspected. If visual inspection also determines it to be poor, the conductor is cut after subsequent electrical characteristic testing confirms the workpiece is defective. Therefore, necessary procedures are performed when poor connection occurs.

[0046] Regarding these issues, according to the first embodiment, the control unit 60 calculates the difference between the first position when the engagement tool 11 descends to its maximum in engagement step R2 and the second position when a specified load is applied to the engagement tool 11 in descent step R4. Based on this difference, the control unit 60 determines whether the engagement of the bump is good or bad. According to this method, the engagement of the bump can be determined regardless of the electrical characteristics of the workpiece. Furthermore, the engagement of the bump can be determined solely based on information obtained in the bump engagement step. That is, the determination result is obtained earlier than the second engagement step. Therefore, the execution of the first and second engagement steps can be stopped based on the determination result. Moreover, by not executing the first and second engagement steps, it is not necessary to cut the wires for electrical characteristic testing, thus reducing the work required in cases of poor engagement.

[0047] According to the first embodiment, the engagement of the bump can be determined at an earlier time, regardless of the electrical characteristics of the workpiece.

[0048] (Example of variation) Figure 7 is a schematic diagram showing another example of the bump engagement step. The bump joining step may also include a plurality of inversion steps R3 and a plurality of descent steps R4. In the example shown in Figure 7, the bump joining step includes inversion step R3a, descent step R4a, inversion step R3b, and descent step R4b. That is, the inversion step R3 and the descent step R4 are repeated alternately twice.

[0049] In the reversal step R3a, the joining tool 11 rises, and then its position changes in the horizontal direction (e.g., the X direction). In the descent step R4a, the joining tool 11 descends until a specified load is applied to it. In the reversal step R3b, the joining tool 11 rises and then moves in the -X direction. The horizontal direction of the movement of the joining tool 11 in the reversal step R3b is opposite to the horizontal direction of the movement in the reversal step R3a. Then, in the descent step R4b, the joining tool 11 descends until a specified load is applied to it. Then, as in the example shown in FIG4, the tail forming step R5, the tail cutting step R6, and the flashing step R7 are performed.

[0050] When performing multiple descent steps, the Z position is detected in each descent step. For example, as shown in Figure 7, the Z position h2 is detected in descent step R4a, and the Z position h3 is detected in descent step R4b.

[0051] When the bump B1 is not fully engaged, as shown in Figure 5, the bump B1 moves along with the horizontal movement of the engagement tool 11. Therefore, in the descent steps R4a and R4b, the Z position of the engagement tool 11 when the specified load is applied varies depending on whether the bump B1 is properly engaged.

[0052] Figure 8 is a schematic diagram showing the variation of the Z position of the joining tool. In Figure 8, the horizontal axis represents time, and the vertical axis represents the Z-position of the engagement tool 11. Solid lines represent the change in Z-position when the bump engagement is good. Dashed lines represent the change in Z-position when the bump engagement is poor. For example, as shown in Figure 8, in the case of good engagement, Z-position h21 is detected in descent step R4a, and Z-position h31 is detected in descent step R4b. In the case of poor engagement, Z-position h22 is detected in descent step R4a, and Z-position h32 is detected in descent step R4b. Z-position h22 is located below Z-position h21, and Z-position h32 is located below Z-position h31.

[0053] The control unit 60 calculates the first difference between the Z position h1 detected in the engagement step R2 and the Z position (h21 or h22) detected in the descent step R4a. Furthermore, the control unit 60 calculates the second difference between the Z position h1 and the Z position (h31 or h32) detected in the descent step R4b.

[0054] When both the first difference and the second difference are above the specified threshold, the control unit 60 determines that the engagement of the bump B1 is good. When neither the first difference nor the second difference reaches the threshold, the control unit 60 determines that the engagement of the bump B1 is poor.

[0055] Alternatively, if the first difference is above a specified threshold value, or if the second difference is above a threshold value, the control unit 60 determines that the engagement of the bump B1 is good. If neither the first nor the second difference reaches the threshold value, the control unit 60 determines that the engagement of the bump B1 is poor.

[0056] When performing multiple reversal steps R3 and multiple descent steps R4, the accuracy of the determination can be further improved by using the Z position in each descent step R4 to determine whether the engagement of the bump B1 is good or not.

[0057] (Second Implementation) Figure 9 is a schematic diagram showing one example of the bump joining process. Figures 4 and 7 show the Z-position detected during the bump engagement step. In contrast, Figure 9 shows the load detected during the bump engagement step.

[0058] As shown in Figure 9, in a portion of the search step R1, the joining step R2, and the descent step R4, a load is applied to the joining tool 11. The load applied to the joining tool 11 is detected by the load sensor 40. In the second embodiment, based on the load on the joining tool 11 detected in the descent step R4, it is determined whether the engagement of the bump B1 is good or not.

[0059] Specifically, in the first embodiment, during the descent step R4, the engagement tool 11 descends until a specified load is detected. In the second embodiment, during the descent step R4, the engagement tool 11 descends until it reaches a specified Z position. The specified Z position is set as the position where the engagement tool 11 contacts the bump B1 when the bump B1 is properly engaged. As shown in Figure 5, compared to the case where the bump B1 is improperly engaged, the engagement tool 11 contacts the bump B1 at a higher position when the bump B1 is properly engaged. That is, when comparing the states where the engagement tool 11 is at the same Z position, the load on the engagement tool 11 when the bump B1 is properly engaged is greater than the load on the engagement tool 11 when the bump B1 is improperly engaged.

[0060] Figure 10 is a schematic diagram showing the variation of the load on the mating tool. In Figure 10, the horizontal axis represents time, and the vertical axis represents the load on the engagement tool 11. Solid lines represent load changes when the bumps are properly engaged. Dashed lines represent load changes when the bumps are improperly engaged. In the example shown in Figure 10, when bump B1 is properly engaged, in descent step R4, load L1 is detected when the engagement tool 11 reaches the designated Z position. When bump B1 is improperly engaged, in descent step R4, load L2 is detected when the engagement tool 11 reaches the designated Z position. Load L2 is less than load L1.

[0061] The control unit 60 compares the load detected in the descent step R4 with a specified threshold value. The threshold value is set as the value between load L1 and load L2. If the detected load is above the threshold value, the control unit 60 determines that the connection is good. If the detected load is below the threshold value, the control unit 60 determines that the connection is poor. If the connection of bump B1 is determined to be poor, the control unit 60 stops the wire bonding step.

[0062] According to the second embodiment, similar to the first embodiment, the engagement of the bump can be determined at an earlier time, regardless of the electrical characteristics of the workpiece.

[0063] (Third Implementation) In the third embodiment of the present invention, during the descent step R4, the duration (length of time) from the start of descent of the engagement tool 11 to the application of a specified load to the engagement tool 11 is detected. Based on this duration, the control unit 60 determines whether the engagement of the protrusion B1 is good or not.

[0064] Figure 11 is a schematic diagram showing the change of the Z position of the joining tool. In Figure 11, similar to Figure 5, the horizontal and vertical axes represent time and Z-position, respectively. Solid and dashed lines represent the changes in Z-position when the bump engagement is good and bad, respectively. In the example shown in Figure 11, when bump B1 is well engaged, in the descent step R4, the time from the start of descent of the engagement tool 11 to the detection of the specified load on the engagement tool 11 is period p1. When bump B1 is poorly engaged, in the descent step R4, the time from the start of descent of the engagement tool 11 to the detection of the specified load on the engagement tool 11 is period p2. Period p2 is longer than period p1.

[0065] The control unit 60 compares the detected period with a specified threshold value. The threshold value is set as the value between period p1 and period p2. If the detected period does not reach the threshold value, the control unit 60 determines that the connection is good. If the detected period is above the threshold value, the control unit 60 determines that the connection is bad. If the connection of bump B1 is determined to be bad, the control unit 60 stops the wire bonding process.

[0066] According to the third embodiment, similar to the first embodiment, the engagement of the bump can be determined at an earlier time, regardless of the electrical characteristics of the workpiece.

[0067] The second or third embodiment described above can also be applied to the bump engagement step, as shown in the variation of the first embodiment, which involves performing a plurality of reversal steps R3 and a plurality of descent steps R4.

[0068] According to the various embodiments of the present invention described above, the control unit 60 can determine whether the engagement of the bump with the first engagement point is good or not based on the specified detection value detected in the descent step R4.

[0069] The "specified detection value" refers to the second position of the engagement tool 11 in the first embodiment, when a specified load is applied to the engagement tool 11 during the descent step R4. The control unit 60 obtains the first position of the engagement tool 11 when the engagement tool 11 descends to its maximum during the engagement step R2. Furthermore, the control unit 60 compares the difference between the first position and the second position with a preset threshold value to determine whether the engagement of the protrusion B1 is good or not.

[0070] The "specified detection value" is the load on the engagement tool 11 when it descends to the specified position during the descent step R4 in the second embodiment. The control unit 60 compares the load with a preset threshold value to determine whether the engagement of the protrusion B1 is good or not.

[0071] The "specified detection value" in the third embodiment refers to the period from the start of the descent step R4 to the application of a specified load to the engagement tool 11. The control unit 60 compares this period with a preset threshold value to determine whether the engagement of the protrusion B1 is good or not.

[0072] Figure 12 is a schematic diagram showing the hardware configuration. As a control unit 60, for example, a computer 90 as shown in Figure 12 is used. The computer 90 includes a CPU (Central Processing Unit) 91, a ROM (Read-Only Memory) 92, a RAM (Random Access Memory) 93, a memory device 94, an input interface 95, an output interface 96, and a communication interface 97.

[0073] ROM92 stores the programs that control the operation of computer 90. ROM92 stores the programs necessary for computer 90 to perform the aforementioned processes. RAM93 functions as a memory area for expanding the programs stored in ROM92.

[0074] CPU 91 includes processing circuitry. CPU 91 uses RAM 93 as its working memory and executes programs stored in at least one of ROM 92 or memory device 94. During program execution, CPU 91 controls various components via system bus 98 to perform various processes.

[0075] The memory device 94 stores the data required for the execution of the program, or the data obtained by executing the program.

[0076] The input interface (I / F) 95 connects the computer 90 to the input device 95a. The input I / F 95 is, for example, a serial bus interface such as USB (Universal Serial Bus). The CPU 91 can read various data from the input device 95a via the input I / F 95.

[0077] An output interface (I / F) 96 connects the computer 90 to the output device 96a. The output I / F 96 may be an image output interface such as a Digital Visual Interface (DVI) or a High-Definition Multimedia Interface (HPMI) (registered trademark). The CPU 91 can send data to the output device 96a via the output I / F 96, enabling the output device 96a to display images.

[0078] The communication interface (I / F) 97 connects the external server 97a to the computer 90. The communication I / F 97 can be, for example, a network card such as a LAN (Local Area Network) card. The CPU 91 can read various data from the server 97a via the communication I / F 97.

[0079] The memory device 94 includes one or more selected from hard disk drives (HDDs) and solid-state drives (SSDs). The input device 95a includes one or more selected from a mouse, keyboard, microphone (audio input), and touchpad. The output device 96a includes one or more selected from a monitor, projector, printer, and speaker. A machine that combines the functions of both input device 95a and output device 96a, such as a touch panel, can also be used.

[0080] The various processes executed by the control unit 60 can be achieved by one computer 90 or by the cooperation of multiple computers 90.

[0081] The processing of the above-mentioned data can also be used as a program that can be executed by a computer and recorded on magnetic disks (floppy disks and hard disks, etc.), optical disks (CD-ROM (Compact Disk-ROM: read-only optical disk), CD-R (Compact Disk-Recordable: recordable optical disk), CD-RW (Compact Disk-Rewritable: rewritable optical disk), DVD-ROM (Digital Video Disk-ROM: digital video disc - read-only memory), DVD±R (Digital Video Disk±Recordable: recordable digital video disc), DVD±RW (Digital Video Disk±Rewritable: rewritable digital video disc) etc.), semiconductor memory, or other non-transitory computer-readable storage media.

[0082] For example, information recorded on a recording medium can be read from a computer (or internal system). The recording format (memory format) on the recording medium is arbitrary. For example, a computer reads a program from the recording medium, and based on that program, the CPU executes the instructions described in the program. In a computer, program retrieval (or reading) can also be performed via a network.

[0083] The embodiments of the present invention include the following features. (Feature 1) A wire splicing device includes: a splicing tool that sequentially dispenses wires; Drive unit, which drives the aforementioned engagement tool; and The control unit controls the aforementioned engagement tool and the aforementioned drive unit; and The above-mentioned control department shall perform: The joining step involves bringing a ball formed at the leading end of the aforementioned wire into contact with the first joining point, deforming the ball into a protrusion, and joining the protrusion with the first joining point; and The descent step involves raising the engagement tool, which holds the wire connected to the protrusion, to change its horizontal position, and then lowering the engagement tool toward the first engagement point. Based on the specified detection value detected in the descent step, the control unit determines whether the engagement of the bump with the first engagement point is good or not. (Feature 2) As in feature 1, the wire bonding device, wherein the above-mentioned detection value includes one or more selected from the following: The position of the engagement tool when the specified load is applied to the engagement tool during the descent step described above; During the descent step described above, the position of the engagement tool is determined when the descent speed of the engagement tool changes to a value below a specified value. In the aforementioned descent step, the load on the engagement tool when it descends to the designated position; and The period from the start of the aforementioned descent step until the application of the specified load to the aforementioned engagement tool. (Feature 3) As in the wire bonding device of feature 1, the control unit obtains the first position when the bonding tool descends to its maximum during the bonding step. The aforementioned detection value includes the second position of the engagement tool when a specified load is applied to the engagement tool during the aforementioned descent step. When the difference between the first position and the second position does not reach a preset threshold value, the control unit determines that the protrusion is not properly engaged. (Feature 4) As in any of features 1 to 3, the wire connection device, wherein the aforementioned control unit When it is determined that the engagement of the aforementioned protrusions is good, a first engagement step is performed, in which the engagement tool is moved above the second engagement point, and the engagement tool, which has a ball formed at the front end of the aforementioned wire, is lowered so that the ball contacts the aforementioned second engagement point; If the engagement of the aforementioned protrusion is deemed to be poor, the first engagement step described above will not be performed. (Feature 5) A control device that controls a wire-jointing device comprising a joining tool for sequentially discharging wires and a drive unit for driving the joining tool. It enables the aforementioned wire coupling device to perform: The joining step involves bringing a ball formed at the leading end of the aforementioned wire into contact with the first joining point, deforming the ball into a protrusion, and joining the protrusion with the first joining point; and The descent step involves raising the engagement tool, which holds the wire connected to the protrusion, causing a change in its horizontal position, and then lowering the engagement tool toward the first engagement point; and Based on the specified detection value detected in the above descent step, it is determined whether the above bump is properly engaged with the above first engagement point. (Feature 6) A control method comprising controlling a wire bonding device equipped with a bonding tool that sequentially releases wires and a drive unit that drives the bonding tool. It enables the aforementioned wire coupling device to perform: The joining step involves bringing a ball formed at the leading end of the aforementioned wire into contact with the first joining point, deforming the ball into a protrusion, and joining the protrusion with the first joining point; and The descent step involves raising the engagement tool, which holds the wire connected to the protrusion, causing a change in its horizontal position, and then lowering the engagement tool toward the first engagement point; and Based on the specified detection value detected in the above descent step, it is determined whether the above bump is properly engaged with the above first engagement point.

[0084] Based on the embodiments described above, a wire bonding device is provided that can determine the goodness of bump engagement at an earlier time, regardless of the electrical characteristics of the workpiece. Furthermore, by executing the aforementioned method for determining engagement goodness during the bump engagement step, the control unit (control device) can determine the goodness of bump engagement at an earlier time, regardless of the electrical characteristics of the workpiece. Based on the aforementioned control method of the control unit, the goodness of bump engagement can be determined at an earlier time, regardless of the electrical characteristics of the workpiece.

[0085] While several embodiments of the present invention have been illustrated above, these embodiments are provided as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments or variations thereof are included within the scope or spirit of the invention, and are included within the scope of the invention described in the patent application and its equivalents. Furthermore, the above embodiments can be combined with each other.

[0086] 1: Workpiece 2: The joint 2a: bump 3: Wire 10: Connector 10a: Position Detection Unit 11: Joining tools 12: Ultrasonic speaker 13: Connecting Arm 13a: Shaft 14: Drive Unit 20:XY platform 30: Joining platform 40: Load sensor 50: Camera device 60: Control Department 90: Computer 91: CPU 92:ROM 93:RAM 94: Memory device 95: Input Interface 95a: Input device 96: Output Interface 96a: Output device 97: Communication Interface 97a: Server 98: System Bus 100: Wire connection device B1: Bump B2: Bump BA: substrate BO: ball C: Chip h1: Z position h2: Z position h21: Z position h22: Z position h3: Z position h31: Z position h32: Z position L1: Load L2: Load P1: First junction point p1: Period P2: Second junction point p2: Period R1: Search Steps R2: Joining Step R3: Reverse steps R3a: Reverse steps R3b: Reverse steps R4: Descent Steps R4a: Descent Steps R4b: Descent Steps R5: Tail Formation Steps R6: Tail Cutting Steps R7: Flash Steps US: Ultrasonic Vibration X: Direction Y: direction Z: Direction

Claims

1. A wire bonding device comprising: a bonding tool that sequentially dispenses wires; a drive unit that drives the bonding tool; and a control unit that controls the bonding tool and the drive unit; wherein the control unit performs: a bonding step in which a ball formed at the leading end of the wire contacts a first bonding point, deforms the ball into a protrusion, and engages the protrusion with the first bonding point; and a lowering step in which the bonding tool, holding the wire connected to the protrusion, rises, changes its position in the horizontal direction, and then lowers the bonding tool toward the first bonding point; wherein the control unit determines whether the engagement of the protrusion with the first bonding point is good or bad based on a specified detection value detected in the lowering step.

2. The wire bonding device of claim 1, wherein the detected value includes one or more selected from: the position of the bonding tool when a specified load is applied to the bonding tool during the descent step; the position of the bonding tool when the descent speed of the bonding tool changes to below a specified value during the descent step; the load on the bonding tool when the bonding tool descends to a specified position during the descent step; and the period from the start of the descent step until the specified load is applied to the bonding tool.

3. The wire bonding device of claim 1, wherein the control unit obtains the first position when the bonding tool descends to its maximum during the bonding step, the detection value includes the second position of the bonding tool when a specified load is applied to the bonding tool during the descent step, and the control unit determines that the bump engagement is defective when the difference between the first position and the second position does not reach a preset threshold value.

4. The wire bonding device according to any one of claims 1 to 3, wherein when the control unit determines that the engagement of the bump is good, it performs a first bonding step, the first bonding step causing the bonding tool to move above the second bonding point, causing the bonding tool with a ball formed at the front end of the wire to descend, and causing the ball to contact the second bonding point; when the engagement of the bump is determined to be poor, the first bonding step is not performed.

5. A control device that controls a wire bonding device having a bonding tool for sequentially discharging wires and a drive unit for driving the bonding tool, wherein the wire bonding device performs: a bonding step in which a ball formed at the leading end of the wire contacts a first bonding point, the ball is deformed into a protrusion and the protrusion engages with the first bonding point; and a lowering step in which the bonding tool, which holds the wire connected to the protrusion, rises, and after changing its position in the horizontal direction, the bonding tool is lowered toward the first bonding point; and based on a specified detection value detected in the lowering step, it is determined whether the engagement of the protrusion with the first bonding point is good or not.

6. A control method comprising controlling a wire bonding device having a bonding tool for sequentially discharging wires and a drive unit for driving the bonding tool, wherein the wire bonding device performs: a bonding step in which a ball formed at the leading end of the wire contacts a first bonding point, the ball is deformed into a protrusion and the protrusion engages with the first bonding point; and a lowering step in which the bonding tool, holding the wire connected to the protrusion, is raised, and after the horizontal position changes, the bonding tool is lowered toward the first bonding point; and based on a specified detection value detected in the lowering step, it is determined whether the engagement of the protrusion with the first bonding point is good or not.

Images