Wire bonding apparatus, control apparatus, and control method

Abstract

The invention provides a wire bonding apparatus, a control apparatus, and a control method capable of determining the bonding quality of a bump at an earlier time. According to one embodiment, a wire bonding device includes: a bonding tool that sends out a wire; a drive unit that drives the engagement tool; and a control unit that controls the bonding tool and the drive unit. The control unit executes a bonding step in which a ball formed at the tip of the lead wire is brought into contact with the first bonding point, the ball is deformed into a bump, and the bump is bonded to the first bonding point. The control unit also executes a lowering step in which the bonding tool holding the lead wire connected to the bump is raised, and after the position in the horizontal direction is changed, the bonding tool is lowered toward the first bonding point. The control unit determines the quality of the bonding of the bump to the first bonding point on the basis of a predetermined detection value detected in the lowering step.

Description

Technical Field

[0001] Embodiments of the present invention relate to a wire bonding device, a control device, and a control method. Background Art

[0002] Wire bonding equipment is often used in the manufacturing process of semiconductor devices. Wire bonding equipment forms bumps, bonds wires, and performs other processes. Wire bonding equipment is required to have a technology that can determine the quality of bump bonding at an earlier timing.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-225637 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] An object of the present invention is to provide a wire bonding apparatus, a control apparatus, and a control method capable of determining the quality of bump bonding at an earlier timing.

[0008] Means for solving problems

[0009] The wire bonding apparatus according to the embodiment includes: a bonding tool for feeding out a wire; a drive unit for driving the bonding tool; and a control unit for controlling the bonding tool and the drive unit. The control unit performs a bonding process in which a ball formed at the front end of the wire is brought into contact with a first bonding point, the ball is deformed into a bump, and the bump is bonded to the first bonding point. The control unit also performs a lowering process in which the bonding tool holding the wire connected to the bump is raised, and after changing its position in the horizontal direction, the bonding tool is lowered toward the first bonding point. The control unit determines whether the bonding of the bump to the first bonding point is good or bad based on a predetermined detection value detected during the lowering process. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram schematically showing a wire bonding apparatus according to an embodiment.

[0011] Figure 2 It is a schematic diagram schematically showing a part of the wire bonding apparatus according to the embodiment.

[0012] Figure 3 (a)~ Figure 3 (c) is a schematic diagram showing an example of a wire bonding process.

[0013] Figure 4 It is a schematic diagram showing an example of a bump bonding process.

[0014] Figure 5 It is a schematic diagram showing the change of the Z position of the bonding tool.

[0015] Figure 6 (a) is a schematic diagram showing the appearance of a bump when bonding is good. Figure 6 (b) is a schematic diagram showing the appearance of a bump in the case of poor bonding.

[0016] Figure 7 It is a schematic diagram showing another example of the bump bonding process.

[0017] Figure 8 It is a schematic diagram showing the change of the Z position of the bonding tool.

[0018] Figure 9 It is a schematic diagram showing an example of a bump bonding process.

[0019] Figure 10 It is a schematic diagram showing the change of the load applied to the welding tool.

[0020] Figure 11 It is a schematic diagram showing the change of the Z position of the bonding tool.

[0021] Figure 12 This is a schematic diagram showing the hardware configuration. DETAILED DESCRIPTION

[0022] The following describes various embodiments of the present invention with reference to the accompanying drawings. The accompanying drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the size between parts, etc. may not necessarily be the same as in reality. Even when representing the same part, the size and ratio may differ depending on the drawing. In this application specification and each figure, the same reference numerals are used for elements that have already been described, and detailed descriptions are omitted as appropriate.

[0023] Embodiments of the present invention relate to a wire bonding apparatus, a control apparatus for controlling the apparatus, and a control method for the apparatus. For example, a wire bonding apparatus is used in the manufacturing process of a semiconductor device to connect pads (electrodes) of a semiconductor chip to leads (electrodes) of a lead frame using thin metal wires.

[0024] (First embodiment)

[0025] Figure 1 It is a schematic diagram schematically showing a wire bonding apparatus according to an embodiment.

[0026] like Figure 1As shown, the wire bonding apparatus 100 according to the embodiment includes a bonding head 10 , a position detecting unit 10 a , an XY stage 20 , a bonding stage 30 , a load sensor 40 , a camera device 50 , and a control unit 60 .

[0027] The bonding head 10 includes a bonding tool 11 , an ultrasonic horn 12 , a bonding arm 13 , and a driving unit 14 .

[0028] The bonding tool 11 feeds out the wire 3, which serves as the bonding material. The bonding tool 11 is, for example, a welding blade. The wire 3 may be, for example, aluminum wire, gold wire, silver wire, or copper wire. The bonding tool 11 brings the wire 3 into contact with the bonded portion 2 of the workpiece 1 placed on the bonding table 30, applying a load to the bonded portion 2. In this embodiment, the bonded portion 2 is the first bonding point P1 or the second bonding point P2, described below.

[0029] The position detection unit 10a detects the Z-direction position of the welding tool 11. For example, an origin is defined at a predetermined position, and the position detection unit 10a detects the vertical position of the welding tool 11 from the origin. The position detection unit 10a is connected to the control unit 60 so as to be communicable.

[0030] The ultrasonic horn 12 generates ultrasonic vibrations. The ultrasonic horn 12 includes an ultrasonic transducer that generates ultrasonic vibrations. The ultrasonic horn 12 supports the bonding tool 11. The ultrasonic vibrations generated by the ultrasonic horn 12 are transmitted to the lead 3 via the bonding tool 11. While the lead 3 is in contact with the bonded portion 2, the ultrasonic vibrations are transmitted to the lead 3, thereby bonding the lead 3 to the bonded portion 2. The ultrasonic horn 12 is electrically connected to the control unit 60.

[0031] The bonding arm 13 supports the ultrasonic horn 12. That is, the bonding arm 13 supports the bonding tool 11 via the ultrasonic horn 12. The bonding arm 13 is provided so as to be rotatable around the shaft portion 13a.

[0032] The drive unit 14 drives the bonding arm 13 in the Z direction about the shaft 13a. The drive unit 14 is, for example, a linear motor. Movement of the bonding arm 13 in the Z direction causes the bonding tool 11 and the ultrasonic horn 12, which are supported by the bonding arm 13, to move in the Z direction. Movement of the bonding tool 11 in the Z direction causes the lead 3 to contact the first bonding point P1 or the second bonding point P2 (described later), allowing a load to be applied from the bonding tool 11. The drive unit 14 is communicatively connected to the control unit 60.

[0033] In this specification, the direction connecting the bonding tool 11 and the workpiece 1 is referred to as the Z direction. The direction perpendicular to the Z direction is referred to as the X direction. The direction perpendicular to the Z and X directions is referred to 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, the direction from the bonding tool 11 toward the workpiece 1 is referred to as "downward," and the direction opposite to "downward" is referred to as "upward."

[0034] The bonding head 10 is mounted on an XY table 20. The XY table 20 is movable in the X and Y directions. The movement of the XY table 20 in the X and Y directions causes the bonding head 10 to move in the X and Y directions. Specifically, the XY table 20 functions as a positioning unit for positioning the bonding tool 11 and other components mounted on the bonding head 10 in the X and Y directions. The XY table 20 is communicatively connected to the control unit 60.

[0035] The bonding table 30 supports the workpiece 1 to be wire-bonded. The bonding table 30 supports the workpiece 1 by suction, for example. The workpiece 1 is a semiconductor chip such as an IC chip or a substrate.

[0036] The load sensor 40 continuously detects the load applied from the welded portion 2 of the workpiece 1 to the welding tool 11. The load sensor 40 comprises, for example, a strain gauge. In the illustrated example, the load sensor 40 is attached to the welding arm 13. The load sensor 40 is communicatively connected to the control unit 60. The load sensor 40 outputs data on the detected load to the control unit 60.

[0037] The camera device 50 captures an image of the ball formed at the tip of the welding tool 11. Based on the image acquired by the camera device 50, parameters of the ball can be calculated.

[0038] The control unit 60 controls the operations 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 wire feed and wire supply speed of the bonding tool 11. The control unit 60 also controls the output of the ultrasonic vibrations generated by the ultrasonic horn 12.

[0039] Furthermore, the control unit 60 can move the bonding tool 11 by operating the drive unit 14. More specifically, the control unit 60 controls the drive unit 14 to drive the bonding arm 13 in the Z direction, thereby controlling the Z-direction position of the bonding tool 11. This allows the control unit 60 to control the magnitude of the load applied from the bonding tool 11 to the workpiece 2.

[0040] The position detection unit 10a detects the Z-direction position of the welding tool 11 driven by the drive unit 14. The position detection unit 10a may also be included in the control unit 60. For example, the position detection unit 10a includes an encoder. When the motor of the drive unit 14 is in operation, the position detection unit 10a detects the rotational direction and rotational position of the motor. Based on the detected rotational direction and position, the position detection unit 10a calculates the Z-direction position of the welding tool 11.

[0041] The control unit 60 can operate the XY stage 20 to move the bonding tool 11. More specifically, the control unit 60 controls the XY stage 20 to drive the bonding head 10 in the X and Y directions, thereby controlling the position of the bonding tool 11 in the X and Y directions.

[0042] Figure 2 It is a schematic diagram schematically showing a part of the wire bonding apparatus according to the embodiment.

[0043] like Figure 2 As shown, a bump 2a is formed on the portion 2 to be joined of a workpiece 1, and a wire 3 is bonded to the bump 2a. The wire bonding apparatus 100 performs the formation of the bump 2a and the bonding of the wire 3 to the bump 2a. For example, the wire bonding apparatus 100 can bond the wire 3 to the portion 2 by generating ultrasonic vibrations from the ultrasonic horn 12 while pressing the wire 3 fed from the bonding tool 11 against the portion 2 to be joined.

[0044] Next, a series of steps for bonding the wires 3 will be described. Figure 3 (a)~ Figure 3 (c) is a schematic diagram showing an example of a wire bonding process.

[0045] like Figure 3 (a)~ Figure 3 As shown in (c), the wire bonding process includes a bump bonding process ( Figure 3 (a)), the first joining step ( Figure 3 (b)) and the second joining step ( Figure 3 (c)) of these three steps. In the example shown in the figure, a chip C is arranged on a substrate BA. There is a first bonding point P1 on the chip C, and a second bonding point P2 on the substrate BA. The substrate BA on which the chip C is arranged is an example of a workpiece 1. The first bonding point P1 and the second bonding point P2 are each an example of a bonded portion 2. Bumps B1 and B2 are formed at the first bonding point P1 and the second bonding point P2, and wires 3 are bonded to these bumps.

[0046] First, if Figure 3As shown in (a), a bump bonding process is performed to form a bump B1 at the first bonding point P1. Specifically, the bonding tool 11 moves to the top of the first bonding point P1 of the chip C. The lead 3 is inserted into the bonding tool 11, and a ball is pre-formed at the front end of the lead 3. For example, by applying a voltage to the lead, a discharge is generated at the front end of the lead, causing the front end of the lead to melt. The molten metal is rounded into a spherical shape due to surface tension and solidifies, thereby forming a ball. The bonding tool 11 is lowered toward the first bonding point P1, and the ball at the front end of the lead 3 contacts the first bonding point P1. While a load is applied to the lead 3, ultrasonic waves are applied to the bonding tool 11. As a result, the ball at the front end of the lead 3 is deformed into a bump B1 on the chip C, and the bump B1 is bonded to the first bonding point P1. Thereafter, the lead 3 is cut by ultrasonic waves, leaving the bump B1 on the chip C. Then, the bonding tool 11 moves from above the first bonding point P1 to above the second bonding point P2.

[0047] After forming the bump B1, as shown in FIG. Figure 3 As shown in (b), the first bonding process is performed. A ball is pre-formed at the front end of the lead 3. The bonding tool 11 is lowered toward the second bonding point P2, and the ball at the front end of the lead 3 contacts the second bonding point P2. While a load is applied to the lead 3, ultrasonic waves are applied to the bonding tool 11. As a result, the ball at the front end of the lead 3 is deformed into a bump B2 on the substrate BA, and the bump B2 is bonded to the second bonding point P2. After the bump B2 is formed, the lead 3 is not cut, and the lead 3 is maintained in a state of being connected to the bump B2.

[0048] After forming the bump B2, as shown in FIG. Figure 3 As shown in (c), the second bonding process is performed. While the bump B2 is connected to the lead 3, the bonding tool 11 moves upward a predetermined distance. Thereafter, the bonding tool 11 bends the lead 3 and moves from above the second bonding point P2 to the first bonding point P1. The lead 3 is bonded to the bump B1 on the chip C. Then, the lead 3 is cut by ultrasonic vibration, and the lead 3 is bonded to the chip C and the substrate BA. The above sequence is an example of wire bonding.

[0049] The first bonding point may be on the substrate BA and the second bonding point may be on the chip C. In this case, after forming the bump B1 on the substrate BA, the bump B2 is formed on the chip C, and the wire 3 is bonded from the bump B2 to the bump B1.

[0050] Next, the bump bonding process will be described in more detail. Figure 4 It is a schematic diagram showing an example of a bump bonding process.

[0051] like Figure 4As shown, the bump bonding process includes a searching process R1, a bonding process R2, a reverse sliding process R3, a descending process R4, a tail forming process R5, a tail cutting process R6 and a spark discharge process R7.

[0052] In the search step R1, the ball BO formed at the tip of the lead 3 inserted into the bonding tool 11 is brought into contact with the surface of the chip C. In the bonding step R2, a load and ultrasonic vibrations are applied to the ball BO, flattening it and bonding it to the surface of the chip C. In the reverse sliding step R3, the bonding tool 11 is raised a predetermined distance and then its horizontal position is changed. In the lowering step R4, the bonding tool 11 is lowered to determine the height of the bump B1. During the reverse sliding and lowering steps R3 and R4, the lead remains connected to the bump. In the tail forming step R5, the bonding tool 11 is raised to a predetermined position to form the tail. In the tail cutting step R6, ultrasonic vibrations are applied while the bonding tool 11 is raised to separate the tail from the bump B1. This forms the bump B1 on the chip C. In the subsequent spark discharge step R7, spark discharge is generated at the tip of the lead 3, melting the tip of the lead 3 and forming a ball at the tip of the lead 3.

[0053] also, Figure 4 The vibration state of ultrasonic vibration (US) in steps R1 to R7 and the detection state of the Z position of the bonding tool 11 are shown. Figure 4 In the figure, h1 represents the Z position of the bonding tool 11 when it is fully lowered in the bonding step R2. For example, in the bonding step R2, the bonding tool 11 is lowered until a predetermined load is detected on the bonding tool 11. Alternatively, the bonding tool 11 is lowered until the lowering speed of the bonding tool 11 falls below a predetermined value. h2 represents the Z position of the bonding tool 11 when it is lowered in the lowering step R4 until a predetermined load is applied to the bonding tool 11 or when the lowering speed of the bonding tool 11 falls below a predetermined value.

[0054] The control unit 60 determines whether the bump B1 is well bonded to the chip C during the bump bonding process. Figure 4 The Z position h1 and the Z position h2 are shown. Good bonding of bump B1 means that bump B1 is bonded to chip C with sufficient bonding strength. Poor bonding of bump B1 means that the bonding strength between bump B1 and chip C is insufficient. For example, if bump B1 is poorly bonded, bump B1 may easily peel off from the surface of chip C.

[0055] The specific method for determining whether a product is good or bad is explained. Figure 5 It is a schematic diagram showing the change of the Z position of the bonding tool.

[0056] exist Figure 5 In FIG. 1 , the horizontal axis represents time, and the vertical axis represents the Z position of the bonding tool 11. The solid line represents the change in the Z position when the bump bonding is good, and the dotted line represents the change in the Z position when the bump bonding is poor.

[0057] exist Figure 5 In the example shown, when the bump B1 is well bonded, the bonding tool 11 is lowered to the Z position h21 in the lowering process R4. When the bump B1 is poorly bonded, the bonding tool 11 is lowered to the Z position h22 in the lowering process R4. The bonding tool 11 is lowered until a specified load is detected. That is, the inventors of the present application found that the Z position of the bonding tool 11 at which the specified load is detected in the case of poor bonding is lower than the Z position of the bonding tool 11 at which the specified load is detected in the case of good bonding. This difference in Z position is believed to be caused by the difference between the state of the bump B1 in the lowering process R4 when the bonding is good and the state of the bump B1 in the lowering process R4 when the bonding is poor.

[0058] Alternatively, the bonding tool 11 may be lowered at a fixed speed, and the descent speed at this time may be detected. When the bonding tool 11 descends, when the output of the driving unit 14 is fixed, the descent speed of the bonding tool 11 decreases when the bonding tool 11 contacts the bump B1. In the descent process, the control unit 60 obtains the Z position of the bonding tool 11 when the descent speed of the bonding tool 11 changes to below a specified value. In the case of obtaining the Z position based on the descent speed, the Z position changes according to the quality of the bonding. The difference in the Z position is also believed to be caused by the difference between the state of the bump B1 in the descent process R4 when the bonding is good and the state of the bump B1 in the descent process R4 when the bonding is poor.

[0059] Figure 6 (a) is a schematic diagram showing the appearance of a bump when bonding is good. Figure 6 (b) is a schematic diagram showing the appearance of a bump in the case of poor bonding.

[0060] like Figure 6As shown in (a), in the reverse sliding process R3 after the bonding process 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 moving direction of the bonding tool 11 can also be inclined relative to the horizontal plane. In the case of good bonding, in the reverse sliding process R3, the position of the bump B1 bonded to the chip C is independent of the movement of the bonding tool 11 in the X direction and does not change. In the subsequent descending process R4, the bonding tool 11 descends, and the lower end of the bonding tool 11 contacts the joint between the bump B1 and the lead 3. At this time, a load is applied to the bonding tool 11. The load sensor 40 detects the specified load, and the descent of the bonding tool 11 stops. Alternatively, when a load is applied to the bonding tool 11, the descent speed of the bonding tool 11 is reduced. If the descent speed is lower than the specified value, the drive unit 14 stops the descent of the bonding tool 11.

[0061] On the other hand, in the case of poor bonding, the bump B1 is easily peeled off from the chip C. Therefore, if Figure 6 As shown in (b), in the reverse sliding process R3, it is considered that the position of the bump B1 changes according to the movement of the bonding tool 11 in the X direction. Thereafter, when the bonding tool 11 is lowered in the descending process R4, the lower end of the bonding tool 11 does not contact the joint between the bump B1 and the lead 3, but contacts the side of the bump B1. When the bonding tool 11 contacts the side of the bump B1, a load is applied to the bonding tool 11. Based on either the load applied to the bonding tool 11 or the descending speed of the bonding tool 11, the descent of the bonding tool 11 stops. Therefore, the Z position at which the bonding tool 11 stops becomes a position lower than the case where the bonding tool 11 contacts the joint between the bump B1 and the lead 3.

[0062] The control unit 60 determines the quality of the bonding of the bump B1 by using the change in the Z position corresponding to the quality of the bonding. Specifically, the control unit 60 calculates the difference between the Z position h1 detected in the bonding process R2 and the Z position (h21 or h22) detected in the lowering process R4. Figure 5 It can be seen that the difference between Z position h1 and Z position h22 is smaller than the difference between Z position h1 and Z position h21. The control unit 60 compares the calculated difference with a pre-set threshold. The threshold 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. If the difference is greater than the threshold, the control unit 60 determines that the bonding of bump B1 is good. If the difference is less than the threshold, the control unit 60 determines that the bonding of bump B1 is poor.

[0063] If it is determined that the bonding of bump B1 is poor, the control unit 60 stops the wire bonding process. The specific timing of the stop is arbitrary. For example, if it is determined that the bonding of bump B1 is poor, the control unit 60 may immediately stop the wire bonding process. Alternatively, the control unit 60 may stop the wire bonding process after executing the tail cutting process R6. In either case, the next first bonding process is not executed. If it is determined that the bonding of bump B1 is good, the control unit 60 executes the next first bonding process and the second bonding process.

[0064] Advantages of the first embodiment will be described.

[0065] If the bumps are poorly bonded, they are likely to peel off. This can result in poor conduction in the workpiece. Therefore, it is preferable to determine the quality of the bond after the bumps are bonded. As reference examples, the following two methods are considered for determining the quality of the bond.

[0066] In the first method, when the bump is bonded, the resistance between the bump and the workpiece or the workpiece's capacitance is measured. If the bump is bonded properly, a change in resistance or capacitance occurs. This change can be used to determine the quality of the bump bond.

[0067] In the second method, the Z position of the bonding tool in the second bonding process is used. During the second bonding process, if the bump is well bonded and remains on the surface of the chip, the wire contacts the bump. If the bump is not well bonded and does not remain on the surface of the chip, the wire contacts the surface of the chip. In other words, the Z position of the bonding tool in the second bonding process changes depending on the quality of the bump bonding. Therefore, the quality of the bump bonding can be determined based on the Z position of the bonding tool in the second bonding process.

[0068] However, in the first method, if the workpiece is not conductive or has a low electrostatic capacitance, it is impossible to determine the quality of the bump joint. In the second method, the quality of the joint is determined when the lead is joined after the bump is formed. If the joint is determined to be poor, the bump joint is inspected by a human through visual confirmation. If the visual inspection also determines that the joint is poor, the lead is cut so that the workpiece can be reliably determined to be poor in subsequent electrical characteristics testing. Therefore, when a poor joint occurs, necessary work is required.

[0069] In response to these issues, according to the first embodiment, the control unit 60 calculates the difference between the first position when the bonding tool 11 is most lowered in the bonding process R2 and the second position when a prescribed load is applied to the bonding tool 11 in the lowering process R4 during the bonding of the bump B1. Then, the control unit 60 determines the quality of the bump bonding based on the difference. According to this method, the quality of the bump bonding can be determined regardless of the electrical characteristics of the workpiece. In addition, the quality of the bump bonding can be determined based only on the information obtained in the bump bonding process. That is, the determination result is obtained at a timing earlier than the second bonding process. Therefore, the execution of the first bonding process and the second bonding process can also be stopped based on the determination result. In addition, by not executing the first bonding process and the second bonding process, there is no need to cut the lead for the electrical characteristics test, and therefore, the work required in the case of poor bonding can also be reduced.

[0070] According to the first embodiment, the quality of the bump bonding can be determined at an earlier timing regardless of the electrical characteristics of the workpiece.

[0071] (Variation)

[0072] Figure 7 It is a schematic diagram showing another example of the bump bonding process.

[0073] The bump bonding process may also include multiple reverse sliding processes R3 and multiple descending processes R4. Figure 7 In the example shown, the bump bonding process includes a reverse sliding process R3a, a lowering process R4a, a reverse sliding process R3b, and a lowering process R4b. That is, the reverse sliding process R3 and the lowering process R4 are repeated alternately twice.

[0074] In the reverse sliding process R3a, the bonding tool 11 rises, and then the position of the bonding tool 11 in the horizontal direction (for example, the X direction) changes. In the descending process R4a, the bonding tool 11 descends until a prescribed load is applied to the bonding tool 11. In the reverse sliding process R3b, the bonding tool 11 rises, and then moves in the -X direction. The horizontal direction in which the bonding tool 11 moves in the reverse sliding process R3b is opposite to the horizontal direction in which the bonding tool 11 moves in the reverse sliding process R3a. Thereafter, in the descending process R4b, the bonding tool 11 descends until a prescribed load is applied to the bonding tool 11. Thereafter, Figure 4 As in the example shown, the tail portion forming step R5 , the tail portion cutting step R6 , and the spark discharge step R7 are performed.

[0075] When multiple descending steps are performed, the Z position is detected in each descending step. Figure 7 As shown, the Z position h2 is detected in the lowering step R4a, and the Z position h3 is detected in the lowering step R4b.

[0076] In the case where the bump B1 is not fully engaged, as Figure 5 As shown, the bump B1 also moves in accordance with the horizontal movement of the bonding tool 11. Therefore, in the lowering step R4a and the lowering step R4b, the Z position of the bonding tool 11 when a predetermined load is applied to the bonding tool 11 changes depending on the quality of bonding of the bump B1.

[0077] Figure 8 It is a schematic diagram showing the change of the Z position of the bonding tool.

[0078] exist Figure 8 In FIG, the horizontal axis represents time, and the vertical axis represents the Z position of the bonding tool 11. The solid line represents the change in the Z position when the bump is well bonded. The dotted line represents the change in the Z position when the bump is poorly bonded. For example, Figure 8 As shown, if the bonding is good, Z position h21 is detected in the lowering step R4a, and Z position h31 is detected in the lowering step R4b. If the bonding is poor, Z position h22 is detected in the lowering step R4a, and Z position h32 is detected in the lowering step R4b. Z position h22 is located below Z position h21, and Z position h32 is located below Z position h31.

[0079] The control unit 60 calculates a first difference between the Z position h1 detected in the joining step R2 and the Z position (h21 or h22) detected in the lowering step R4a. The control unit 60 also calculates a second difference between the Z position h1 and the Z position (h31 or h32) detected in the lowering step R4b.

[0080] If the first difference is greater than a predetermined threshold and the second difference is greater than a threshold, the control unit 60 determines that the bump B1 is well bonded. If the first difference is less than the threshold or the second difference is less than the threshold, the control unit 60 determines that the bump B1 is poorly bonded.

[0081] Alternatively, the control unit 60 may determine that the bump B1 is well bonded if the first difference is greater than a predetermined threshold or the second difference is greater than a threshold. If both the first difference and the second difference are less than the threshold, the control unit 60 determines that the bump B1 is poorly bonded.

[0082] When a plurality of reverse sliding steps R3 and a plurality of descending steps R4 are performed, the accuracy of the determination can be further improved by using the Z position in each descending step R4 to determine the quality of the bonding of the bump B1 .

[0083] (Second embodiment)

[0084] Figure 9 It is a schematic diagram showing an example of a bump bonding process.

[0085] exist Figure 4 as well as Figure 7 In FIG, the Z position detected in the bump bonding process is shown. In contrast, in Figure 9 , the load detected during the bump bonding process is shown.

[0086] like Figure 9 As shown, a load is applied to the bonding tool 11 during a portion of the search step R1, the bonding step R2, and the lowering step R4. The load applied to the bonding tool 11 is detected by the load sensor 40. In the second embodiment, the quality of the bonding of the bump B1 is determined based on the load applied to the bonding tool 11 detected in the lowering step R4.

[0087] Specifically, in the first embodiment, in the descending step R4, the bonding tool 11 descends until a predetermined load is detected. In the second embodiment, in the descending step R4, the bonding tool 11 descends until the bonding tool 11 reaches a predetermined Z position. The predetermined Z position is set to a position where the bonding tool 11 contacts the bump B1 when the bump B1 is well bonded. Figure 5 As shown in FIG. 1 , when bump B1 is well bonded, bonding tool 11 contacts bump B1 at a higher position than when bump B1 is poorly bonded. In other words, when bonding tool 11 is at the same Z position, the load applied to bonding tool 11 when bump B1 is well bonded is greater than the load applied to bonding tool 11 when bump B1 is poorly bonded.

[0088] Figure 10 It is a schematic diagram showing the change of the load applied to the welding tool.

[0089] exist Figure 10 In FIG, the horizontal axis represents time, and the vertical axis represents the load applied to the bonding tool 11. The solid line represents the change in load when the bump is well bonded. The dotted line represents the change in load when the bump is poorly bonded. Figure 10 In the example shown, if bump B1 is bonded well, load L1 is detected when bonding tool 11 reaches a predetermined Z position during lowering step R4. If bump B1 is bonded poorly, load L2 is detected when bonding tool 11 reaches a predetermined Z position during lowering step R4. Load L2 is smaller than load L1.

[0090] The control unit 60 compares the load detected during the lowering step R4 with a predetermined threshold. The threshold is set to a value between loads L1 and L2. If the detected load is greater than the threshold, the control unit 60 determines that the bonding is good. If the detected load is less than the threshold, the control unit 60 determines that the bonding is poor. If the bonding of bump B1 is determined to be poor, the control unit 60 stops the wire bonding process.

[0091] According to the second embodiment, similarly to the first embodiment, the quality of the bump bonding can be determined at an earlier timing regardless of the electrical characteristics of the workpiece.

[0092] (Third embodiment)

[0093] In the third embodiment of the present invention, in the lowering step R4, the period (length of time) from the start of lowering of the welding tool 11 to the application of a predetermined load to the welding tool 11 is detected. The control unit 60 determines the quality of the bonding of the bump B1 based on this period.

[0094] Figure 11 It is a schematic diagram showing the change of the Z position of the bonding tool.

[0095] exist Figure 11 In, with Figure 5 Similarly, the horizontal axis and the vertical axis represent time and Z position, respectively. The solid line and the dotted line represent the change in Z position when the bump is well bonded and poorly bonded, respectively. Figure 11 In the example shown, if the bump B1 is bonded well, the length of time from the start of the lowering of the bonding tool 11 to the detection of the application of a predetermined load to the bonding tool 11 in the lowering step R4 is period p1. If the bump B1 is bonded poorly, the length of time from the start of the lowering of the bonding tool 11 to the detection of the application of a predetermined load to the bonding tool 11 in the lowering step R4 is period p2. Period p2 is longer than period p1.

[0096] The control unit 60 compares the detected period with a predetermined threshold. The threshold is set to a value between period p1 and period p2. If the detected period is less than the threshold, the control unit 60 determines that the bonding is good. If the detected period is greater than the threshold, the control unit 60 determines that the bonding is poor. If the bonding of bump B1 is determined to be poor, the control unit 60 stops the wire bonding process.

[0097] According to the third embodiment, similarly to the first embodiment, the quality of the bump bonding can be determined at an earlier timing regardless of the electrical characteristics of the workpiece.

[0098] The second embodiment or the third embodiment described above can also be applied to the bump bonding process in which a plurality of reverse sliding steps R3 and a plurality of descending steps R4 are performed, as shown in the modified example of the first embodiment.

[0099] According to the above-described embodiments of the present invention, the control unit 60 determines whether the bump is bonded to the first bonding point based on the predetermined detection value detected in the lowering step R4 .

[0100] In the first embodiment, the "predetermined detection value" is the second position of the bonding tool 11 when a predetermined load is applied to the bonding tool 11 in the lowering step R4. The control unit 60 obtains the first position of the bonding tool 11 when the bonding tool 11 is fully lowered in the bonding step R2. The control unit 60 then compares the difference between the first and second positions with a preset threshold value to determine the quality of the bonding of the bump B1.

[0101] In the second embodiment, the "predetermined detection value" is the load applied to the welding tool 11 when the welding tool 11 is lowered to a predetermined position in the lowering step R4. The control unit 60 compares the load with a preset threshold value to determine whether the bump B1 is properly bonded.

[0102] In the third embodiment, the "predetermined detection value" is the period from the start of the lowering step R4 to the application of a predetermined load to the welding tool 11. The control unit 60 compares the period with a preset threshold value to determine whether the bonding of the bump B1 is good or bad.

[0103] Figure 12 This is a schematic diagram showing the hardware configuration.

[0104] As the control unit 60, for example, Figure 12 The computer 90 shown includes a CPU 91 , a ROM 92 , a RAM 93 , a storage device 94 , an input interface 95 , an output interface 96 , and a communication interface 97 .

[0105] The ROM 92 stores a program for controlling the operation of the computer 90. The ROM 92 stores a program required for the computer 90 to implement the above-described processing. The RAM 93 functions as a storage area for expanding the program stored in the ROM 92.

[0106] The CPU 91 includes a processing circuit and uses the RAM 93 as a working memory to execute a program stored in at least one of the ROM 92 and the storage device 94. While executing the program, the CPU 91 controls each component via the system bus 98 and executes various processes.

[0107] The storage device 94 stores data necessary for executing the program and data obtained by executing the program.

[0108] An input interface (I / F) 95 can connect the computer 90 to an input device 95a. The input I / F 95 is, for example, a serial bus interface such as USB. The CPU 91 can read various data from the input device 95a via the input I / F 95.

[0109] The output interface (I / F) 96 connects the computer 90 to an output device 96a. The output I / F 96 is, for example, a video output interface such as a Digital Visual Interface (DVI) or a High-Definition Multimedia Interface (HPMI (registered trademark)). The CPU 91 can transmit data to the output device 96a via the output I / F 96, causing the output device 96a to display an image.

[0110] A communication interface (I / F) 97 can connect a server 97a outside the computer 90 to the computer 90. The communication I / F 97 is, for example, a network card such as a LAN card. The CPU 91 can read various data from the server 97a via the communication I / F 97.

[0111] The storage device 94 includes one or more selected from a hard disk drive (HDD) and a solid-state drive (SSD). The input device 95a includes one or more selected from a mouse, a keyboard, a microphone (for audio input), and a touchpad. The output device 96a includes one or more selected from a monitor, a projector, a printer, and a speaker. A device that has both the functions of the input device 95a and the output device 96a, such as a touchpad, may also be used.

[0112] Each process executed by the control unit 60 may be implemented by a single computer 90 or by cooperation of a plurality of computers 90 .

[0113] The processing of the above-mentioned various data can also be recorded as a program that can be executed by a computer on a disk (floppy disk and hard disk, etc.), an optical disk (CD-ROM, CD-R, CD-RW, DVD-ROM, DVD±R, DVD±RW, etc.), a semiconductor memory or other non-transitory computer-readable storage medium.

[0114] For example, the information recorded in the recording medium can be read by a computer (or embedded system). In the recording medium, the recording format (storage format) is arbitrary. For example, the computer reads a program from the recording medium, and based on the program, the CPU executes the instructions recorded in the program. In the computer, the program can also be obtained (or read) via a network.

[0115] The embodiments of the present invention include the following features.

[0116] (Feature 1)

[0117] A wire bonding device comprising:

[0118] bonding tools, feeding out leads;

[0119] a driving unit for driving the bonding tool; and

[0120] A control unit controls the bonding tool and the driving unit.

[0121] The control unit performs the following steps:

[0122] a bonding step of bringing a ball formed at a front end of the lead into contact with a first bonding point, deforming the ball into a bump, and bonding the bump to the first bonding point; and

[0123] a lowering step of raising the bonding tool holding the lead connected to the bump, changing the horizontal position, and then lowering the bonding tool toward the first bonding point;

[0124] The control unit determines whether the bump is bonded to the first bonding point based on a predetermined detection value detected in the lowering step.

[0125] (Feature 2)

[0126] In the wire bonding apparatus according to feature 1,

[0127] The above-mentioned detection value includes one or more selected from the following: the position of the above-mentioned bonding tool when a specified load is applied to the above-mentioned bonding tool in the above-mentioned descending process, the position of the above-mentioned bonding tool when the descending speed of the above-mentioned bonding tool changes to below a specified value in the above-mentioned descending process, the load applied to the above-mentioned bonding tool when the above-mentioned bonding tool descends to a specified position in the above-mentioned descending process, and the period from the start of the above-mentioned descending process to the application of the specified load to the above-mentioned bonding tool.

[0128] (Feature 3)

[0129] In the wire bonding apparatus according to feature 1,

[0130] The control unit obtains a first position when the bonding tool is most lowered in the bonding step,

[0131] The detection value includes a second position of the welding tool when a predetermined load is applied to the welding tool in the lowering step.

[0132] The control unit determines that the bump has been poorly bonded when a difference between the first position and the second position is smaller than a preset threshold value.

[0133] (Feature 4)

[0134] In the wire bonding apparatus according to any one of features 1 to 3,

[0135] The control unit is:

[0136] If the bump is judged to be well bonded, a first bonding step is performed. In the first bonding step, the bonding tool is moved to above the second bonding point, and the bonding tool having a ball formed on the front end of the lead is lowered so that the ball contacts the second bonding point.

[0137] If it is determined that the bump bonding is defective, the first bonding step is not performed.

[0138] (Feature 5)

[0139] A control device controls a wire bonding device including a bonding tool for feeding a wire and a driving unit for driving the bonding tool, wherein:

[0140] The control device causes the wire bonding device to perform the following steps:

[0141] a bonding step of bringing a ball formed at a front end of the lead into contact with a first bonding point, deforming the ball into a bump, and bonding the bump to the first bonding point; and

[0142] a lowering step of raising the bonding tool holding the lead connected to the bump, changing the horizontal position, and then lowering the bonding tool toward the first bonding point;

[0143] The quality of the bonding of the bump to the first bonding point is determined based on a predetermined detection value detected in the lowering step.

[0144] (Feature 6)

[0145] A control method is a method for controlling a wire bonding apparatus including a bonding tool for feeding a wire and a driving unit for driving the bonding tool, wherein:

[0146] The control method enables the wire bonding apparatus to perform the following steps:

[0147] a bonding step of bringing a ball formed at a front end of the lead into contact with a first bonding point, deforming the ball into a bump, and bonding the bump to the first bonding point; and

[0148] a lowering step of raising the bonding tool holding the lead connected to the bump, changing the horizontal position, and then lowering the bonding tool toward the first bonding point;

[0149] The quality of the bonding of the bump to the first bonding point is determined based on a predetermined detection value detected in the lowering step.

[0150] According to the embodiments described above, a wire bonding apparatus is provided that can determine the quality of bump bonding at an earlier timing, regardless of the electrical characteristics of the workpiece. Furthermore, a control unit (control device) executes the above-described method for determining the quality of bonding during the bump bonding process, thereby determining the quality of bump bonding at an earlier timing, regardless of the electrical characteristics of the workpiece. The control method described above by the control unit makes it possible to determine the quality of bump bonding at an earlier timing, regardless of the electrical characteristics of the workpiece.

[0151] Several embodiments of the present invention have been described above. These embodiments are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the main purpose of the invention. These embodiments and their modifications are included in the scope and main purpose of the invention, and are included in the invention described in the scope of the patent claims and the scope equivalent thereto. The above embodiments can be combined with each other and implemented.

Claims

1. A wire bonding apparatus comprising: bonding tools, feeding out leads; a driving unit for driving the bonding tool; and A control unit controls the bonding tool and the driving unit. The control unit performs the following steps: a bonding step of bringing a ball formed at a front end of the lead into contact with a first bonding point, deforming the ball into a bump, and bonding the bump to the first bonding point; and a lowering step of raising the bonding tool holding the lead connected to the bump, changing the horizontal position, and then lowering the bonding tool toward the first bonding point; The control unit determines whether the bump is bonded to the first bonding point based on a predetermined detection value detected in the lowering step.

2. The wire bonding apparatus according to claim 1, wherein The above-mentioned detection value includes one or more selected from the following: the position of the above-mentioned bonding tool when a specified load is applied to the above-mentioned bonding tool in the above-mentioned descending process, the position of the above-mentioned bonding tool when the descending speed of the above-mentioned bonding tool changes to below a specified value in the above-mentioned descending process, the load applied to the above-mentioned bonding tool when the above-mentioned bonding tool descends to a specified position in the above-mentioned descending process, and the period from the start of the above-mentioned descending process to the application of the specified load to the above-mentioned bonding tool.

3. The wire bonding apparatus according to claim 1, wherein The control unit obtains a first position when the bonding tool is most lowered in the bonding step, The detection value includes a second position of the welding tool when a predetermined load is applied to the welding tool in the lowering step. The control unit determines that the bump has been poorly bonded when a difference between the first position and the second position is smaller than a preset threshold value.

4. The wire bonding apparatus according to any one of claims 1 to 3, wherein: The control unit is: If the bump is judged to be well bonded, a first bonding step is performed. In the first bonding step, the bonding tool is moved to above the second bonding point, and the bonding tool having a ball formed on the front end of the lead is lowered so that the ball contacts the second bonding point. If it is determined that the bump bonding is defective, the first bonding step is not performed.

5. A control device for controlling a wire bonding apparatus including a bonding tool for feeding a wire and a driving unit for driving the bonding tool, wherein: The control device causes the wire bonding device to perform the following steps: a bonding step of bringing a ball formed at a front end of the lead into contact with a first bonding point, deforming the ball into a bump, and bonding the bump to the first bonding point; as well as a lowering step of raising the bonding tool holding the lead connected to the bump, changing the horizontal position, and then lowering the bonding tool toward the first bonding point; The quality of the bonding of the bump to the first bonding point is determined based on a predetermined detection value detected in the lowering step.

6. A control method for a wire bonding apparatus comprising a bonding tool for feeding a wire and a driving unit for driving the bonding tool, wherein: The control method enables the wire bonding apparatus to perform the following steps: a bonding step of bringing a ball formed at a front end of the lead into contact with a first bonding point, deforming the ball into a bump, and bonding the bump to the first bonding point; as well as a lowering step of raising the bonding tool holding the lead connected to the bump, changing the horizontal position, and then lowering the bonding tool toward the first bonding point; The quality of the bonding of the bump to the first bonding point is determined based on a predetermined detection value detected in the lowering step.

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