Bonding apparatus, control method of bonding apparatus, and storage medium

Abstract

This invention provides a bonding device, a control method for the bonding device, and a storage medium for appropriately correcting the curvature of the wire tail, enabling the formed free air ball to reach the target position with good accuracy for bonding. The bonding device includes: an actuator for moving a capillary tube through which the wire is inserted along the insertion direction of the wire; a clamp for clamping and releasing the wire; an air torch for forming a free air ball at the front end of the wire; and a control unit for controlling the actuator, the clamp, and the air torch. When the wire is clamped by the clamp, the control unit uses the air torch to form a free air ball, actuates the actuator to bring the capillary tube close to the free air ball, and when the clamp releases the wire, actuates the actuator to pull the capillary tube downwards toward the bonding object, pressing and fixing the free air ball to the bonding object.

Description

Technical Field

[0001] This invention relates to a coupling device, a control method for the coupling device, and a storage medium. Background Technology

[0002] A bonding device is known to connect the electrode of a semiconductor chip fixed on a substrate to an electrode on the substrate using bonding wires, or to form lead wires on such electrodes. Lead wires are known to be formed by methods such as forming a free air ball at the leading end of the wire, applying a cut to the middle portion of the wire using a wire cutter or the like, and then stretching the wire to cut it at the cut after bonding to the electrode to be bonded (see, for example, Patent Document 1).

[0003] [Existing Technical Documents]

[0004] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2001-274186 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] The bonding wire extending from the capillary tube sometimes bends at the wire tail, which is the end of the bonding wire delivered from the capillary tube, due to rebound during the previous bonding or the impact of discharge when a free air ball is formed at the leading end. This bending at the wire tail can cause misalignment at the bonding position. Patent Document 1 discloses a process where, after forming the free air ball, the bonding wire is pulled back so that the free air ball abuts against the leading end of the capillary tube, and then bonded to the electrode pad. While it is expected that the bending at the wire tail can be corrected by moving the wire tail relative to the through-hole of the fixed capillary tube in this manner, this process relies on the pull-back force generated by the tensioner of the wire supply device to move the slender wire tail with the molten free air ball formed independently. There is a concern that the free air ball may detach or become misaligned due to the impact of the free air ball abutting against the leading end of the capillary tube.

[0008] The present invention was made to solve this problem and provides a joining device, etc., that properly corrects the bending of the line tail so that the formed free air ball reaches the target position with good accuracy for joining.

[0009] [Technical means to solve the problem]

[0010] The bonding device of the first embodiment of the present invention includes: an actuator that moves a capillary tube through which the wire is inserted along the insertion direction of the wire; a clamp that performs clamping and releasing actions relative to the wire; an air torch that forms a free air ball at the front end of the wire; and a control unit that controls the actuator, the clamp, and the air torch. When the wire is clamped by the clamp, the control unit uses the air torch to form a free air ball, causing the actuator to operate so that the capillary tube approaches the free air ball. When the wire is released by the clamp, the control unit operates the actuator to pull the capillary tube downward toward the bonding object, pressing and fixing the free air ball to the bonding object.

[0011] The control method of the bonding device according to the second embodiment of the present invention includes: a free air ball forming step, in which a wire supplied by a supply device is clamped by a clamp and a free air ball is formed at the front end of the wire by an air torch; an approach step, in which an actuator is activated to move a capillary tube through which the wire is inserted in the insertion direction so that it approaches the free air ball; and a bonding step, in which the actuator is activated while the clamp is releasing the wire and the capillary tube is pulled down toward the bonding object, and the free air ball is pressed and fixed to the bonding object.

[0012] The control program of the bonding device in the third embodiment of the present invention causes the computer to perform the following steps: a free air ball forming step, in which the wire supplied by the supply device is clamped by a clamp and a free air ball is formed at the front end of the wire using an air torch; an approach step, in which the actuator is activated to move the capillary tube through which the wire is inserted in the insertion direction so that it approaches the free air ball; and a bonding step, in which the actuator is activated while the wire is released by the clamp and the capillary tube is pulled down toward the bonding object, pressing and fixing the free air ball to the bonding object.

[0013] [The effects of the invention]

[0014] The present invention provides a joining device that can properly correct the bending of the line tail and ensure that the formed free air ball reaches the target position with good accuracy for joining. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the joining device of this embodiment viewed from the side.

[0016] Figure 2 This is a schematic diagram of the joining device of this embodiment as viewed from the top surface.

[0017] Figure 3 This is a system structure diagram of the coupling device.

[0018] Figure 4 (a) ~ Figure 4 (i) is a process diagram representing the formation sequence of the pin lines.

[0019] Figure 5 (a) ~ Figure 5 (f) is a process diagram showing the formation sequence of the loop in another embodiment.

[0020] Figure 6 (a) ~ Figure 6 (d) is a process diagram showing the sequence when there is only one clamp in another embodiment.

[0021] Explanation of icon numbers

[0022] 100: Connecting device

[0023] 111: Torch

[0024] 112: Capillary

[0025] 113: Transducer

[0026] 114: Z-rotation mechanism

[0027] 122: Support arm

[0028] 123: Sliding Mechanism

[0029] 131: First gripper

[0030] 132: Second clamp

[0031] 140: Shooting Unit

[0032] 150: Actuator

[0033] 160: XY Workbench

[0034] 161: Supporting base

[0035] 170: Platform

[0036] 181: Storage Department

[0037] 182: Input / Output Devices

[0038] 190: Control Department

[0039] 200: Wire EDM machine

[0040] 210: Cut-in section

[0041] 300: Line

[0042] 300a: Free Air Balloon (FAB)

[0043] 300b: Incision

[0044] 310: Pin line

[0045] 320: Substrate

[0046] 321: Pad electrode

[0047] 322: Lead electrode Detailed Implementation

[0048] Figure 1 This is a schematic diagram of the joining device 100 of this embodiment, viewed from the side. Additionally, Figure 2 This is a schematic diagram of the same engagement device 100 as viewed from the top surface. The engagement device 100 shown in the figure is represented by a simplified structure or mechanism for ease of understanding, or the size or shape of the components differs from the actual device, or components not directly related to the characteristic components of this embodiment are omitted, but it is not intended to represent a difference from the actual engagement device.

[0049] The bonding apparatus 100 is an apparatus that uses a substrate or wafer, a lead frame, etc., as bonding objects and forms lead wires at predetermined locations on these bonding objects. Figure 1 The figure shows the case where the pad electrode 321 on the substrate 320, which is the bonding object, has lead lines 310 formed. The substrate 320 is fixed to the upper surface of the stage 170. Furthermore, in this embodiment, as shown in the coordinate axes in the figure, the vertical axis is set as the Z-axis, and the horizontal plane is set as the XY plane. The upper surface of the stage is parallel to the XY plane.

[0050] By driving a portion of the actuator 150, the XY stage 160 is displaced relative to the upper surface of the stage 170 in the XY plane direction. The support base 161 is fixed to the XY stage 160 and mainly directly or indirectly supports the torch 111, capillary tube 112, transducer 113, Z-rotation mechanism 114, support arm 122, sliding mechanism 123, first gripper 131, second gripper 132, imaging unit 140, and wire cutting machine 200.

[0051] The torch 111 includes a discharge electrode at its front end. The torch 111 applies a voltage to the discharge electrode, thereby forming a molten free air ball (FAB) at the front end of the wire 300, which is fed from the front end of the capillary 112. The specific sequence of FAB formation will be described later. The capillary 112 functions to guide the vertically inserted wire 300 and supply it to the pad electrode 321, and during bonding, the front end presses the wire 300 against the pad electrode 321. During bonding, the transducer 113 applies ultrasonic vibrations to the vicinity of the front end of the wire 300 via the capillary 112, securing the FAB to the pad electrode 321. The transducer 113 can also apply heat to the FAB.

[0052] The first gripper 131 has a hand that clamps the wire 300 into the upper part of the capillary 112, and performs clamping and releasing actions on the wire 300 according to the control of the engagement device 100. The capillary 112, transducer 113, and first gripper 131 are supported by a Z-rotation mechanism 114. The Z-rotation mechanism 114 is supported at its base end on a support base 161, and is displaced relative to the support base 161 in the Z-axis direction by driving a portion of the actuator 150. That is, according to the operation of the Z-rotation mechanism 114, the capillary 112, transducer 113, and first gripper 131 can approach or move away from the surface of the stage 170.

[0053] The second clamp 132 is disposed above the first clamp 131 and, like the first clamp 131, has a hand for clamping the wire 300. It performs clamping and releasing actions on the wire 300 under the control of the coupling device 100. The second clamp 132 is supported and fixed to the support base 161, and the position for clamping or releasing the wire 300 is at a fixed height relative to the surface of the platform 170. The wire 300 is a coupling wire supplied from a wire supply unit (not shown) containing a tensioner or a rotating spool. The raw material for the wire 300 may be, for example, gold wire, silver wire, copper wire, etc.

[0054] The wire EDM machine 200 is a cutting machine used to form a cut on the wire 300. The wire EDM machine 200 mainly includes a cutting section 210 and a receiving section 220. The cutting section 210 and the receiving section 220 are arranged facing each other and are brought closer (closed) or separated (opened) by driving a portion of the actuator 150. The cut formed on the wire 300 is a notch or notch, and when stretched from both sides, the tensile stress concentrates, causing the wire 300 to break.

[0055] The wire cutting machine 200 is supported at its base end by a support arm 122, which in turn is supported at its base end by a sliding mechanism 123. By driving a portion of the actuator 150, the sliding mechanism 123 is displaced horizontally relative to the support base 161. This horizontal displacement enables the following action: the cutting portion 210 and the receiving portion 220, in their separated (open) state, are inserted into the wire 300 from the capillary 112 in a horizontal clamping manner, or pulled out in the opposite direction.

[0056] The imaging unit 140 includes an imaging element that outputs an image signal and an optical system that images the substrate 320 onto the imaging element. The bonding device 100 uses the image signal output by the imaging unit 140 to identify the position of the substrate 320, thereby causing the XY stage 160, etc., to move.

[0057] Figure 3This is a system structure diagram of the joining device 100. The control system of the joining device 100 mainly includes a control unit 190, a storage unit 181, an input / output device 182, a torch 111, a transducer 113, a first gripper 131, a second gripper 132, a shooting unit 140, and actuators 150. Components that undergo displacement, such as the Z-rotation mechanism 114, the XY worktable 160, and the wire cutting machine 200, are driven by the corresponding actuators in the actuators 150 included in the joining device 100.

[0058] The control unit 190 is a processor (central processing unit (CPU)) that performs control and program execution processing of the bonding device 100. The processor may also be configured to cooperate with computing chips such as application-specific integrated circuits (ASICs) or graphics processing units (GPUs). The control unit 190 reads the control program stored in the storage unit 181 and executes various processes related to bonding.

[0059] Storage unit 181 is a non-volatile storage medium, such as a hard disk drive (HDD). In addition to storing programs for controlling or processing the engagement device 100, storage unit 181 can also store various parameter values, functions, lookup tables, etc., used for control or calculation. Input / output devices 182 include, for example, a keyboard, mouse, and display monitor, and are devices that handle menu operations performed by the user or provide prompts to the user. For example, control unit 190 can display images acquired by the self-capture unit 140 on the display monitor, which is one of the input / output devices 182.

[0060] When the torch 111 receives a discharge indication signal from the control unit 190, it applies a voltage to the electrodes. When the voltage is applied, an arc discharge occurs between the electrodes and the wire tip, forming a feasibility barrier (FAB) at the tip of the wire 300. When the transducer 113 receives an excitation signal from the control unit 190, it causes the oscillator to vibrate. The ultrasonic vibration achieved by the transducer 113 facilitates the bonding of the wire 300.

[0061] The first clamp 131 and the second clamp 132 receive an instruction signal from the control unit 190 and perform an opening and closing action. When the wire 300 is placed in the engagement device 100, the opening action is the action of clamping the wire 300, and the closing action is the action of releasing the wire 300.

[0062] The imaging unit 140 receives an imaging request signal from the control unit 190 and performs imaging, and sends the image output by the imaging element to the control unit 190 in the form of an image signal. The actuator 150 receives a drive signal from the control unit 190 and causes the wire cutting machine 200, or the first clamp 131, or the second clamp 132 to open or close, or to move other components.

[0063] The sequence in which the lead line 310 is formed on the pad electrode 321 of the bonding device 100 having this structure will be described. Figure 4 (a) ~ Figure 4 (i) is a process diagram showing the formation sequence of pin line 310. Figure 4 (a) ~ Figure 4 (i) is arranged in the order of operations, and the following description is also in the order of operations. Furthermore, Figure 4 (a) ~ Figure 4 The various diagrams of (i) are from... Figure 2 The observation of the direction A shown is only a major part extracted and schematically illustrated.

[0064] Figure 4 (a) indicates the initial state of the process, in which the wire 300 is fed from the front end of the capillary 112 at a set feed rate. The control unit 190 holds the first clamp 131 in a clamped state (the state of clamping the wire 300) to prevent the fed wire from being pulled back by the tensioner (not shown).

[0065] Then, as Figure 4 As shown in (b), the control unit 190 applies a voltage to the torch 111, generating an arc discharge between the electrode and the wire tip, producing FAB 300a. If FAB 300a is generated, then as... Figure 4 As shown in (c), the control unit 190 causes the first gripper 131 to transition from the clamping state to the disengaged state (the state of the release line 300).

[0066] The control unit 190 displaces the sliding mechanism 123, causing the cutting part 210 and the receiving part 220 to insert horizontally relative to the delivered wire 300, such as... Figure 4 As shown in (d), the actuator 150 is activated, causing the cutting part 210 and the receiving part 220 to approach each other and be in a mutually closed state.

[0067] Then as Figure 4 As shown in (g), the control unit 190 actuates the actuator 150 to separate the cutting section 210 from the receiving section 220. Through this continuous operation of the cutting section 210 and the receiving section 220, a cut 300b is formed in the line 300. After the formation of the cut 300b is completed, the control unit 190 moves the cutting section 210 and the receiving section 220 to the standby position.

[0068] If the cutting-in part 210 and the receiving part 220 are moved to the standby position, then as Figure 4 As shown in (f), while the control unit 190 holds the wire 300 in the second gripper 132 and maintains the wire 300 in a stationary state, it drives the actuator 150, which actuates the Z-rotation mechanism 114, to bring the capillary 112 closer to the FAB 300a. By bringing the capillary 112 closer to the FAB 300a in this manner, even if the wire tail bends, the bent portion will be straightened and corrected as it passes through the insertion hole of the capillary 112 on the outer periphery of the wire tail. Furthermore, the front end of the capillary 112 can also approach the FAB 300a with a slight gap. When it comes into contact with the FAB 300a, the descent speed of the capillary 112 can be reduced just before contact to mitigate the impact on the FAB 300a. In addition, in this embodiment, the first gripper 131 also descends along with the descent of the capillary 112.

[0069] Then, as Figure 4 As shown in (g), while the first gripper 131 remains in a disengaged state, the second gripper 132 also transitions to a disengaged state, causing the capillary 112 to descend. As the capillary 112 descends, the FAB 300a is pushed down by the front end of the capillary 112 and descends together. At this time, since both grippers are in a disengaged state, a new line 300 corresponding to the descent of the FAB 300a is drawn from the line supply device. Furthermore, when the FAB 300a reaches the pad electrode 321, the front end of the capillary 112 flattens the FAB 300a onto the pad electrode 321. In this state, the control unit 190 vibrates the transducer 113, securing the FAB 300a to the pad electrode 321.

[0070] After that, as Figure 4 As shown in (h), the control unit 190 maintains the first gripper 131 in the disengaged state while simultaneously actuating the Z-rotation mechanism 114, thereby pulling the capillary tube 112 up to a preset height. Furthermore, it transfers the first gripper 131 to the clamped state, as... Figure 4 As shown in (i), when the capillary 112 is pulled up further, the wire 300 breaks at the cut 300b and is in a state where the lead wire 310 is formed on the pad electrode 321.

[0071] Alternatively, the following order can also be considered: from Figure 4 The process of (e) causes the first gripper 131 to be transferred to a disengaged state and causes the capillary 112 to begin descending, during which the front end of the capillary 112 contacts the FAB 300a, in which state, as Figure 4As shown in (g), FAB 300a is brought into contact with pad electrode 321. However, the wire 300 is pulled back at the moment the first clamp 131 is transferred to the disengaged state by the action of the tensioner. Therefore, in this sequence, the impact when the front end of capillary 112 contacts FAB 300a is large, and there is a concern that the molten FAB 300a may be misaligned or fall off. Therefore, as in Figure 4 As described in process (f), it is ideal to keep line 300 stationary while bringing capillary 112 close to FAB300a.

[0072] The above describes an embodiment of forming lead wires 310 using bonding device 100. However, bonding device 100 with the same structure can also be used to connect pad electrodes on a semiconductor chip to lead electrodes on a substrate in a loop, for example. Figure 5 (a) ~ Figure 5 (f) is a process diagram showing the formation sequence of the loop in another embodiment.

[0073] Figure 5 (a) ~ Figure 5 The process of (c) and Figure 4 (a) ~ Figure 4 The process in (c) is the same. In the case of forming a loop, the step of forming the cut 300b is omitted. Figure 4 (d) and Figure 4 The process of (e), therefore in Figure 5 After step (c), the capillary 112 and the first gripper 131 are lowered toward the FAB 300a. Figure 5 The process of (d). Specifically, while the control unit 190 holds the wire 300 in place by the second gripper 132 and maintains the wire 300 in a stationary state, it drives the actuator 150, which actuates the Z-rotation mechanism 114, to bring the capillary 112 close to the FAB 300a. Through the above process, as in Figure 4 As described in process (f), the bent portion is straightened and leveled in a straight line.

[0074] Then, as Figure 5As shown in (e), while the control unit 190 maintains the first gripper 131 in a disengaged state, the second gripper 132 also transitions to a disengaged state, causing the capillary 112 to descend. As the capillary 112 descends, the FAB 300a is pushed down by the front end of the capillary 112 and descends together. At this time, since both grippers are in a disengaged state, a new line 300 corresponding to the descent of the FAB 300a is drawn from the line supply device. Furthermore, when the FAB 300a reaches the pad electrode 321, the front end of the capillary 112 flattens the FAB 300a onto the pad electrode 321. In this state, the control unit 190 vibrates the transducer 113, securing the FAB 300a to the pad electrode 321 (initial bonding).

[0075] Then, as Figure 5 As shown in (f), the control unit 190 lifts the first clamp 131 and capillary 112, which are in a dissociated state, and lowers the capillary 112 to form a loop toward the lead electrode 322, pressing the wire 300 onto the lead electrode 322. Then, the control unit 190 vibrates the transducer 113 to fix the wire 300 onto the lead electrode 322 (second connection).

[0076] The structure of the coupling device 100, including the first clamp 131 and the second clamp 132, has been described above. However, even if the coupling device includes one clamp relative to the line 300, the FAB 300a can be fixed to the electrode in the same way. Figure 6 (a) ~ Figure 6 (d) is a process diagram showing the sequence when there is only one clamp in another embodiment.

[0077] Figure 6 (a) indicates the initial state of the process, in which the wire 300 is fed from the front end of the capillary 112 at a set feed rate. The control unit 190 holds the clamp 133 in a clamped state to prevent the fed wire from being pulled back by the tensioner (not shown).

[0078] Then, as Figure 6 As shown in (b), the control unit 190 applies a voltage to the torch 111, generating an arc discharge between the electrode and the wire tip, producing FAB 300a. If FAB 300a is generated, then as... Figure 6 As shown in (c), while maintaining the clamping state of the gripper 133, the control unit 190 drives the actuator 150, which actuates the Z-rotation mechanism 114, to bring the capillary 112 close to the FAB300a. Through this process, as in... Figure 4 As described in process (f), the bent portion is straightened and leveled in a straight line.

[0079] Then, as Figure 6As shown in (d), the control unit 190 transfers the gripper 133 to a disengaged state, causing the capillary 112 to descend. As the capillary 112 descends, the FAB 300a is pushed down by the front end of the capillary 112 and descends together. At this time, since the gripper 133 is in a disengaged state, a new line 300 corresponding to the descent of the FAB 300a is drawn from the line supply device. Furthermore, when the FAB 300a reaches the pad electrode 321, the front end of the capillary 112 flattens the FAB 300a onto the pad electrode 321. In this state, the control unit 190 vibrates the transducer 113, fixing the FAB 300a to the pad electrode 321. Furthermore, the process described above can be used as part of the process for forming lead lines, or as part of the process for forming loops.

Claims

1. A coupling device, comprising: An actuator that moves the capillary tube through which the wire is inserted along the insertion direction of the wire; A clamp, which performs clamping and releasing actions relative to the line; A torch forms a free air sphere at the leading end of the line; as well as The control unit controls the actuator, the gripper, and the gas torch. While the control unit is holding the wire with the clamp, it uses the air torch to form the free air ball, causing the actuator to operate and bring the capillary close to the free air ball. While the clamp is releasing the wire, the actuator is operated and the capillary is pulled down toward the bonding object, pressing and fixing the free air ball to the bonding object.

2. The engagement device according to claim 1, wherein the clamp comprises a first clamp movable along the insertion direction and a second clamp not movable along the insertion direction. The actuator causes the first gripper to move along the insertion direction. When the control unit is holding the wire with the second clamp and the first clamp is releasing the wire, it brings the capillary close to the free air balloon, and when both the first clamp and the second clamp are releasing the wire, it pulls the capillary down toward the bonding object.

3. The joining device according to claim 2, wherein the control unit pulls down the first clamp, which is in a state of releasing the wire, together with the capillary toward the joining object.

4. The joining device according to claim 1, comprising a wire cutting machine for forming a cut on the wire fed from the capillary. After the free air sphere is formed, the control unit controls the wire cutting machine to form the cut on the wire, and then brings the capillary close to the free air sphere.

5. A control method for a coupling device, comprising: The free air balloon forming step involves using a clamp to hold a line supplied by a supply device, and using an air torch to form a free air balloon at the front end of the line. In the approach step, the actuator is activated to move the capillary tube through which the wire is inserted along the insertion direction, bringing it closer to the free air ball. as well as In the joining step, with the clamp releasing the line, the actuator is activated and the capillary is pulled down toward the joining object, pressing and securing the free air ball to the joining object.

6. A computer-readable storage medium storing thereon a control program for a coupling device, causing a computer to perform the following steps: The free air balloon forming step involves using a clamp to hold a line supplied by a supply device, and using an air torch to form a free air balloon at the front end of the line. In the approach step, the actuator is activated to move the capillary tube through which the wire is inserted along the insertion direction, bringing it closer to the free air ball. as well as In the joining step, with the clamp releasing the line, the actuator is activated and the capillary is pulled down toward the joining object, pressing and securing the free air ball to the joining object.

Images