Wire Bonding Equipment Threading System

Abstract

The present invention provides a method for automatically threading a wire in a wire bonding device, the method comprising the following steps: extending a wire tail from a winding reel and positioning the wire tail in a wire positioning device; and placing the wire tail in a straightening position of the wire positioning device. At the straightening position, the wire tail is straightened by a wire manipulation device, and the straightened wire tail is transferred to a threading position. At the threading position, the straightened wire tail is received by a wire threading device and threaded through a capillary of the wire bonding device.

Description

Technical Field

[0001] The invention relates to a wire threading system of a wire bonding device, and in particular to a method and a device for automatically threading a wire in a wire bonding device. Background Art

[0002] In the wire bonding process, conductive wires are typically bonded between electronic bonding pads found on an electronic device, such as a semiconductor die and a substrate to which the die is attached. The substrate is typically a semiconductor lead frame. Electrical connections may also be established between bonding pads found on individual semiconductor dies. The bonds are formed by a bonding tool in the form of a capillary attached to an ultrasonic transducer, generating ultrasonic energy at the tip of the capillary.

[0003] In wire bonders used to make so-called "ball bonds", the bonding head that carries the bonding tool is designed to pivot and rock about a suitable mass point. When ultrasonic bonding is performed, an ultrasonic transducer is mounted to the bonding head, wherein the ultrasonic transducer includes a stacked piezoelectric driver coupled to an alarm and a capillary-shaped bonding tool arranged at the end of the alarm. The bonding wire is usually made of gold, aluminum or copper, which can be fed from the winding disk of the bonding wire through the hole of the capillary to the tip of the capillary. The bond is completed by applying ultrasonic energy and force to the tip of the capillary, welding the wire at the tip of the capillary to the bonding pad.

[0004] However, every time the wire reel is changed or when the bonding wire escapes from the capillary, the bonding wire needs to be passed through the wire reel and all intermediate devices to pass it out of the capillary, which is a process that is prone to problems.

[0005] Therefore, it would be beneficial to provide a wire-through bonding technique that is improved over the prior art. Summary of the invention

[0006] Therefore, an object of the present invention is to seek to provide a technology to overcome at least some of the aforementioned problems existing in the prior art.

[0007] According to a first aspect of the present invention, a method for automatically threading a wire in a wire bonding device is provided, the method comprising the following steps: extending a wire tail portion of a wire from a wire winding reel and positioning the wire tail portion in a wire positioning device; placing the wire tail portion at a straightening position of the wire positioning device; at the straightening position, straightening the wire tail portion by a wire manipulation device, and transferring the straightened wire tail portion to a threading position; and at the threading position, receiving the straightened wire tail portion by a wire threading device and threading the straightened wire tail portion through a capillary of the wire bonding device.

[0008] By providing a straightened wire tail at a straightening position and transferring the straightened wire tail to a threading position, the wire can be automatically threaded through the capillary of the wire bonding equipment without manual intervention.

[0009] The lead wire positioning device is provided with a positioning hole, the shape of which is suitable for receiving the wire tail and guiding the wire tail to the lead wire straightening position.

[0010] The locating hole is defined by a pair of converging opposing faces that converge at the locating face in the straightened position.

[0011] The positioning surface extends in a vertical direction so that the wire tail is also oriented in a vertical direction.

[0012] The step of positioning the wire tail at the straightened position further includes: pushing the wire tail extending through the positioning hole toward the positioning surface by a wire tail pushing device disposed in the lead positioning device.

[0013] The wire tail pushing device may include an airflow generator, which is used to generate an airflow to push the wire tail to extend through the positioning hole toward the positioning surface.

[0014] The airflow generator may further retain the wire tail extending through the positioning hole on the positioning surface.

[0015] At the straightening position, the step of straightening the wire tail may include clamping the wire tail with a first pair and a second pair of wire retainers, respectively, adjacent to the straightening position.

[0016] The step of straightening the wire tail may further include the step of moving at least one of the first and second pairs of wire retainers away from the other pair while clamping the wire tail to straighten at least a portion of the wire tail.

[0017] The method may further include the step of cutting excess wire at a free end of the wire tail to separate from the straightened wire tail.

[0018] At the threading location, the step of receiving the straightened wire tail may further include pulling the straightened wire tail to the threading location through at least one of the first and second pairs of wire retainers.

[0019] The method may further include the step of generating tension in the lead wire by an air tensioner when the straightened wire tail is pulled to the threading position.

[0020] The step of threading the straightened wire tail through the capillary further comprises the step of moving the threading device from a parked position to a threading position aligned with the capillary.

[0021] The method may further include the step of guiding the straightened wire tail to a capillary tube through at least one wire guide included in the threading device.

[0022] The wire guide may include a slot guide channel having an elongated slot extending along an axial length thereof, the slot being aligned with the air tensioner and the capillary tube.

[0023] The lead guide may include a slot limiter operably configured to close the slot.

[0024] The slot restrictor may comprise a flexible cover operably configured to move between a closed position and an open position in use to close and open the slot.

[0025] The method may further include the step of generating an air flow within the wire guide to move the flexible cover between the closed position and the open position.

[0026] The slot limiter may include a spring coupling the first half of the lead guide with the second half of the lead guide and operably configured to move between a closed position and an open position to close and open the slot in use.

[0027] The method may further include the step of obtaining position information about the lead guide relative to the capillary by imaging a location identifier coupled to the lead threading device.

[0028] The location identifier may comprise a visual index operably configured to be imaged by a wire bonding imaging device in use.

[0029] The method may further include the step of placing the wire guide with the translation stage and the controller to align the wire guide with the capillary.

[0030] According to a second aspect of the present invention, there is provided a wire bonding threading device, which is configured to perform the method according to the first aspect of the present invention.

[0031] According to a third aspect of the present invention, there is provided a wire bonding threading device, comprising: a wire positioning device, which is operably configured to receive a wire tail from a winding reel and position the wire tail at a straightened position during use; a wire manipulation device, which is operably configured to straighten the wire tail at the straightened position during use and transfer the straightened wire tail to a threading position; and a wire threading device, which is operably configured to receive the straightened wire tail at the threading position during use and pass the straightened wire tail through a capillary of the wire bonding device.

[0032] The lead wire positioning device is provided with a positioning hole, which is shaped to receive the wire tail from the winding drum.

[0033] The locating hole is defined by a pair of converging opposing faces that converge at the locating face in the straightened position.

[0034] The locating surface may extend along a vertical axis such that the wire tail is also oriented along the vertical axis.

[0035] The lead positioning device may include a wire tail pushing device, which is operably configured to push the wire tail extending in the positioning hole towards the positioning surface located at the straightened position during use.

[0036] The wire tail pushing device may include an airflow generator which is operably configured to generate an airflow in use to push the wire tail extending in the positioning hole towards the positioning surface.

[0037] The airflow generator may be further operably configured to retain a wire tail extending within the locating hole against the locating surface.

[0038] The lead handling device may include first and second pairs of lead retainers operably configured to clamp the wire tail in a straightened position in use.

[0039] When clamping the wire tail, one pair of the first and second pairs of wire retainers may be operably configured to move apart from each other in use to straighten at least a portion of the wire tail.

[0040] When clamping the wire tail, one pair of the first and second pairs of wire retainers are operably configured to move apart from each other along a vertical axis in use to straighten the wire tail along the vertical axis.

[0041] At least one of the first and second pairs of lead retainers is operably configured to deliver the straightened wire tail to a cutting position so that excess wire at a free end is cut off to separate the straightened wire tail.

[0042] At least one of the first and second pairs of wire anchors is operably configured to reposition the straightened wire tail to a threading position in use.

[0043] At least one of the first and second pairs of wire retainers is operably configured to reposition the straightened wire tail to a threading position via an air tensioner during use.

[0044] The lead threading device is operably configured to move from a parked position to a threading position aligned with the capillary in use.

[0045] The wire threading device may include at least one wire guide operably configured to guide the straightened wire tail along a vertical axis to the capillary tube in use.

[0046] The lead guide may include a slot guide channel having an elongated slot extending along an axial length thereof, the axial length being aligned with the vertical axis.

[0047] The lead guide may include a slot limiter operably configured to close the slot in use.

[0048] The slot restrictor may comprise a flexible cover operably configured to move between a closed position and an open position in use to close and open the slot.

[0049] The flexible cover is movable between a closed position and an open position by air flow within the wire guide.

[0050] The slot limiter may include a spring coupling the first half of the lead guide with the second half of the lead guide and operably configured to move between a closed position and an open position to close and open the slot in use.

[0051] The lead threading device may include a positioning identifier operably configured to provide information regarding a centerline of the lead guide relative to the capillary tube, in use.

[0052] The location identifier may comprise a visual index operably configured to be imaged by a wire bonding imaging device in use.

[0053] The wire threading device may include a translation stage and a controller operably configured to align a centerline of the wire guide with a centerline of the capillary in use.

[0054] The above and other features, aspects and advantages will be better understood from the following description, appended claims and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Embodiments of the present invention will be described hereinafter, by way of example only, with reference to the accompanying drawings, in which:

[0056] Figure 1 The main components of an automated wire bonding machine are shown schematically.

[0057] Figure 2 The main components of a wire bonding threading device according to an embodiment are schematically shown.

[0058] Figure 3A-3C A top view (A), a side view (B), and a perspective view (C) of a horizontal guiding device according to an embodiment are shown.

[0059] FIG. 4A to FIG. 4G The major steps performed by the lead handling device in conjunction with the horizontal guiding apparatus are shown.

[0060] FIG. 5A to FIG. 5M The configuration and operation of a wire bonding threading device according to one embodiment are shown.

[0061] Figure 6 A guide of the wire threading device is shown coaxially aligned with the opening of the air tensioner and the hole in the capillary tube.

[0062] Fig. 7A shows a perspective view of a lead threading device; Figure 7B A partial cross-sectional view of a lead threading device is shown.

[0063] Fig. 8A and Figure 8B Imaging of small holes or patterns on the positioning marks is shown.

[0064] Fig.9A and Fig. 9B An operational diagram of the automatic moving mechanism is shown.

[0065] Fig. 10A and Fig. 10B Operation of the slot and spacer cover is shown to enable the threading device to move to the park position.

[0066] Fig.11A and Fig. 11B Another design of an open slot is shown.

[0067] In the drawings, the same components are denoted by the same reference numerals. DETAILED DESCRIPTION

[0068] Below, before elaborating on the embodiments in detail, an overview will be given first. Embodiments of the present invention provide a technique for automatically threading a bonding wire in a wire bonding device. Multiple components are required to perform the threading procedure. A wire positioning device can capture and position the wire tail of the bonding wire so that the wire tail can be straightened and passed through the threading device, wherein the threading device can thread the straightened wire tail through the capillary of the wire bonding device. In this way, the threading of the wire bonding device can be made reliable and predictable, and can also be performed automatically, thereby increasing production and reducing downtime. Specifically, according to some embodiments, the threading procedure starts from a winding reel, usually passes through an air path air tensioner, passes through one or more wire clamps and a capillary of the wire bonding device, so that the capillary can prepare the required wire tail to continue the bonding procedure. According to some embodiments, three main features are provided, which help guide the wire from the winding reel to the capillary, and these three features are an automatic wire positioning device, an automatic wire straightening and conveying device, and an automatic threading device. By means of the above device, the operator does not need to personally attend to the machine or manually thread the wire after changing the winding reel or when the bonding wire escapes from the capillary during the production process. Therefore, this embodiment can help to minimize the machine downtime of the wire bonding equipment during production, and can also reduce or even completely eliminate the need for operators to operate the bonding equipment on the production floor. This helps to improve the mean time between auxiliary operations, which is an important criterion for wire bonding. In particular, the automatic wire threading device, as an important component of the wire bonding machine, can enable the production to be carried out without operator attendance for several consecutive days or even longer.

[0069] Automatic threading

[0070] Figure 1 The main components of the automatic wire bonding device 105 are schematically shown. The automatic wire bonding device 105 includes a wire bonding threading device 110 (see Figure 2 ), the wire bonding threading device 110 automatically threads the wire bonding device 120.

[0071] Wire Bonding Equipment

[0072] The wire bonding apparatus 120 includes a wire reel holder 9 that accommodates a wire reel 10, which provides a bonding wire 50 having a free end forming a wire tail. The wire reel 10 is usually carried on an electric wire winder 11, so that the wire reel 10 can be rotated in a clockwise and / or counterclockwise direction to extend and / or shorten the wire tail. The wire reel holder 9 can also accommodate a wire guide rod 12. The wire reel holder 9 is usually located above a substrate 100, and wire bonding is performed on the substrate.

[0073] Other components of the wire bonding apparatus 120 are located between the substrate 100 and the wire reel holder 9. In particular, a capillary 29 is provided near the substrate 100, and an air tensioner body 25 is provided near the wire reel holder 9. A first wire clamp 26 and a second wire clamp 27 are located between the capillary 29 and the air tensioner body 25. A ventilator 17 is provided between the air tensioner body 25 and the wire reel 9. The ventilator 17 can generate an air flow in the direction A, which helps to apply a slight tension to the upright portion of the bonding wire 50 extending through the wire bonding apparatus 120.

[0074] There are two typical situations where it may be necessary to automatically thread the bonding wire 50. The first is when the winding reel 10 needs to be replaced, usually when the existing winding reel 10 has been used up or a different bonding wire is needed to perform a new bonding process. The second is when the bonding wire 50 has been pulled out of the capillary 29 during bonding.

[0075] For the first case, a new winding drum 10 can be placed on the winding drum holder 9, and usually, the wire tail at the first position 14 will extend vertically and hang in the horizontal guide device 13 located at the outlet of the winding drum holder 9, so that the wire tail can fall beside the lead guide rod 12 when it falls from the winding drum 10. When the winding drum 10 is replaced, it can be positioned in the above position by an operator, or it can be automatically positioned at the first position 14 by making the winding drum 10 perform a preset rotation to extend the wire tail to the first position 14.

[0076] For the second case, the wire tail may be located at, for example, the second position 15 or the third position 16. If the bonding wire 50 is located at the second position 15, it has completely separated from the wire bonding device 120 and is flying in the airflow generated by the ventilation device 17. If the bonding wire 50 is located at the third position 16, it is partially or completely separated from the wire bonding device 120, but the airflow of the ventilation device 17 partially deflects it. In either case, the winding drum 10 can be rotated counterclockwise to shorten the freely hanging wire tail, so that the wire tail is obtained at the first position 14.

[0077] Wire Bonding Threading Equipment

[0078] Figure 2Components of a wire bonding threading device 110 are shown that thread a wire tail from a wire reel fixture 9 through an air vent 17 and through an air tensioner body 25, a first wire clamp 26, a second wire clamp 27, and a capillary 29. These components include a horizontal guide device 13, an upper wire carrier 20 located near the horizontal guide device 13, and a lower wire carrier 21 located at a distal end of the horizontal guide device 13. A wire threading device 33 may be positioned to be cooperatively positioned to interleave between the air tensioner body 25, the first wire clamp 26, the second wire clamp 27, and the capillary 29. As will be described in more detail below, the horizontal guide device 13 cooperates with the upper wire carrier 20, the lower wire carrier 21, and the wire threading device 33 to automatically thread a wire tail 50 through the air tensioner body 25, the first wire clamp 26, the second wire clamp 27, and the capillary 29 via the air vent 17.

[0079] Horizontal guide equipment

[0080] Figure 3A-3C A top view (A), a side view (B) and a perspective view (C) of a horizontal guide device 13 according to an embodiment are shown. The horizontal guide device 13 is located below the winding drum 10 and above the ventilation device 17. The horizontal guide device 13 includes a rear guide block 1, a front guide block 2 and a door 7, and a gradually tapering or narrowing cavity 6 is defined by the door 7. The blowing channel 4 is toward the first end of the cavity 6, and the suction channel 3 is toward the second end of the cavity 6. The cavity 6 is wider as it is closer to the blowing channel 4, and narrower as it is closer to the suction channel 3. The cavity 6 ends when it extends to the positioning surface 5, thereby defining the target position 8. The airflow can be adjusted for different sizes of the bonding wire 50, and the inner surface defining the cavity 6 can allow the bonding wire 50 to move freely without affecting the surface of the bonding wire 50.

[0081] In operation, the tail of the wire enters the cavity 6 through the widest part aligned with the first position 14. Air can be introduced through the blowing channel 4 and then discharged through the suction channel 3. Therefore, the lead entrained in the air flow between the blowing channel 4 and the suction channel 3 can move from the blowing channel 4 to the suction channel 3. Then, the lead is guided by the rear guide block 1, the door 7 and / or the front guide block 2 through the narrowing cavity 6 until the target position 8, and then the lead is maintained at the target position 8 by the air flow. The suction force generated by the suction channel 3 also helps to keep the tail of the wire against the positioning position 8. Finally, a vertically suspended tail of the wire is generated at the positioning position 8 and is transmitted by the lead manipulation device 130. Therefore, it can be seen that the horizontal guiding device 13 is designed to automatically retrieve the tail of the wire and position it to the target position 8 for processing by the next device, so that the tail of the wire can be accurately transmitted for threading.

[0082] Lead handling device

[0083] FIG. 4A to FIG. 4G The main steps performed by the lead manipulator 130 in cooperation with the horizontal guide device 13 are shown. Figure 4A As shown, generally in one of the above-mentioned situations, when it is detected that automatic threading is required, the wire bonding threading device 110 is triggered. Accordingly, the winding disk 10 can be rotated so that the wire tail extends through the horizontal guide device 13 at the first position 14.

[0084] like Figure 4B As shown, the horizontal guiding device 13 is activated so that the airflow pushes the wire tail 50 toward the target position 8 .

[0085] The lead manipulation device 130 includes an upper lead carrier 20, a lower lead carrier 21, and respective drive systems. The upper lead carrier 20 and the lower lead carrier 21 are controlled individually or uniformly in the X, Y, and Z directions, respectively. Each carrier 20, 21 has a pair of clamping plates to clamp the lead, and at the same time, has one or more guides to limit the position of the lead. As will be explained in more detail below, generally, the lead manipulation device 130 is operated to achieve: capturing the wire tail at the target position 8; moving the upper lead carrier 20 and the lower lead carrier 21 apart from each other to stretch the lead, thereby causing strain hardening in this portion of the bonding wire 50, cutting and transmitting the free end of the wire tail for corresponding processing at the processing position, guiding the remaining wire tail to the opening of the air tensioner body 25, and / or guiding the wire tail into the air tensioner body 25.

[0086] Accordingly, if Figure 4C As shown, the upper lead carrier 20 and the lower lead carrier 21 move to a position below the target position 8 and clamp the wire tail.

[0087] Then, if Figure 4D As shown, the upper lead carrier 20 and the lower lead carrier 21 are moved apart to stretch and strain harden a portion 150 of the bonding wire 50 .

[0088] like Figure 4E As shown, the remaining portion 160 of the bonding wire 50, which is the portion that is generally not straightened toward the free end of the bonding wire 50, is removed and transported to the processing position so as to be processed by the lower lead carrier 21. Then, the lower lead carrier 21 is returned to position and clamps the free end of the portion 150.

[0089] like Figure 4F As shown, the upper lead carrier 20 and the lower lead carrier 21 move together to transfer the wire tail between the portion 150 and the winding drum 10 into the air flow of the ventilation device 17.

[0090] like Figure 4GAs shown, the upper lead carrier 20 and the lower lead carrier 21 together move the lead portion 150 to the air tensioner opening 24 of the air tensioner body 25, which is located near the winding drum holder 9. Then, the lower lead carrier 21 releases the portion 150, and the upper lead carrier 20 moves toward the air tensioner opening 24, so that the portion 150 is sucked into the air tensioner opening 24. The air tensioner 25 is connected to an air source so that an air flow can pass through the air tensioner 25, thereby facilitating the suction of the portion 150 into the air tensioner 25.

[0091] FIG. 5A to FIG. 5M The configuration and operation of a wire bonding threading device 100A according to an embodiment are shown. The configuration shown in the figure is similar to the above-described configuration. In particular, a winding reel fixture 9A having a wire winder 11A is provided, and the wire winder 11A is driven by a motor. The wire reel fixture 9A has a wire guide rod 12A and a horizontal guide device 13A. The front of the pivoting wire reel fixture 9A is to receive a door 7A of the horizontal guide device 13A. The wire reel is placed on the wire winder 11A and operates in a similar manner to the above-described wire reel fixture 9.

[0092] The upper lead carrier 20A and the lower lead carrier 21A together form a lead handler 130A that operates in a similar manner to the lead handler 130 described above.

[0093] The ventilation device 17A is located below the winding drum holder 9A and operates in a similar manner to the ventilation device 17 described above.

[0094] The air tensioner body 25A is positioned above the wire bonding apparatus 120A components, which also operates in a similar manner to the air tensioner body 25 and wire bonding apparatus 120 described above.

[0095] The wire threading apparatus 33A may be moved in a similar manner to the wire threading apparatus 33 described above to interleave with the wire bonding apparatus 120A.

[0096] Operation of the lead handling device

[0097] like Figure 5B As shown, the wire manipulation device 130A can move from a first position (1) to receive the wire tail at a target position 8A; before moving to a second position (2), the wire tail has been straightened; before moving to a third position (3), excess wire has been removed; before moving to a fourth position (4), the wire tail interacts with the airflow generated by the venting device 17A, so that the wire tail is embedded in the air tensioner opening 24A of the air tensioner body 25A.

[0098] Figure 5CDetailed top view of the horizontal guide device 13A. It can be seen that a rear guide block 1A and a door 7A acting on the front guide block are provided. A cavity 6A is formed between the guide block 1A and the door 7A, which is narrower the closer to the target position 8A adjacent to the positioning surface 5A.

[0099] like Figure 5D , Figure 5E and Fig. 5F As shown, the wire tail is located at the target position 8A and is clamped by the upper lead carrier 20A and the lower lead carrier 21A at the first position (1). The upper lead carrier 20A and the lower lead carrier 21A move apart to stretch the wire tail and form the straightened portion 150A.

[0100] like Figure 5G , Figure 5H and Fig.5I As shown, the upper lead carrier 20A and the lower lead carrier 21A move to the second position (2), where the cutter 28A cuts off the remaining portion 160A from the straightened portion 150A.

[0101] like Figure 5J and Figure 5K As shown, the upper wire carrier 20A and the lower wire carrier 21A are moved to a third position ( 3 ), where the upright portion of the bonding wire 50 is placed in the air flow of the vent 17 .

[0102] like Figure 5L and Figure 5M As shown, the upper lead carrier 20A and the lower lead carrier 21A move the portion 150 to a fourth position (4) above the air tensioner opening 24A.

[0103] Lead threading device

[0104] like Figure 6 As shown, the guide of the lead threading device 33A is coaxially aligned with the air tensioner opening 24A and the hole in the capillary 29, which will be explained in detail below. Through the above arrangement, the portion 150A is inserted into the air tensioner opening 24A and can pass through the air tensioner body 25A, and then pass through the first lead clamp 26 and the second lead clamp 27, and then enter the capillary 29.

[0105] Fig. 7A A perspective view of the lead threading device 33A is shown, Figure 7BA partial cross-sectional view of the lead threading device 33A is shown. The lead threading device 33A continues to perform the threading procedure on the lead handling device 130A, wherein the portion 150A has entered the air tensioner body 25A. After the portion 150A comes out of the air tensioner body 25A, the lead threading device 33A will guide the portion 150A to successively pass through the lead clamps 26, 27 and the capillary 29. When the portion 150A passes through the capillary 29, the portion 150A is tested to see whether to continue threading so that any contaminated leads can be removed before starting the production operation. Once the threading is completed, the lead handling device 130A and the lead threading device 33A return to the original position to start or continue production.

[0106] like Fig. 7A and 7B As shown, the lead threading device 33A has a first guide insert 34 in the form of a narrowing or tapering inlet channel near the outlet of the air tensioner body 25A. The first guide insert 34 extends to the second guide insert 35, wherein the second guide insert 35 is also in the form of a narrowing or tapering inlet channel near the outlet of the first guide insert 34. The third guide insert 36 is also in the form of a narrowing or tapering inlet channel near the outlet of the second guide insert 35. The first guide insert 34, the second guide insert 35 and the third guide insert 36 are coaxially aligned.

[0107] like Figure 6 As shown, once the lead threading device 33A has moved from its origin to the threading position, the first lead clamp 26 is located between the first guide insert 34 and the second guide insert 35. The second lead clamp 27 is located between the second guide insert 35 and the third guide insert 36. The transducer 28 and the capillary 29 are located below the third guide insert 36.

[0108] As described above, the hole extending along the air tensioner body 25 is coaxially aligned with the capillary tube 29, and extends and coaxially aligns with the hole through the first guide insert 34, the second guide insert 35, and the third guide insert 36. A passage 40 is provided in the lead threading device 33A, which couples the first guide insert 34, the second guide insert 35, and the third guide insert 36 with the fitting 38. The air provided by the fitting 38 can be transmitted through the passage 40 to the hole extending through the first guide insert 34, the second guide insert 35, and the third guide insert 36.

[0109] In operation, the wire threading device 33A can be positioned in a threading position where the holes extending through the first guide insert 34, the second guide insert 35 and the third guide insert 36 are coaxially aligned with the holes extending through the air tensioner body 25 and the capillary 29, which will be described in detail below.

[0110] The air tensioner body 25A transmits the portion 150A received in the air tensioner opening 24A toward the first guide insert 34. The airflow provided by the fitting 38 can cause air to be drawn into the first guide insert 34, thereby facilitating the portion 150 to be drawn into and through the first guide insert 34, and then through the first lead clamp 26 into the second guide insert 35. The air provided to the second guide insert 35 can cause air to be drawn into the second guide insert 35, thereby causing the portion 150 to be drawn into and through the second guide insert 35, and then through the second lead clamp 27 into the third guide insert 36. The air provided by the fitting 38 flows through the third guide insert 36, which draws air through the third guide insert 36, thereby drawing the portion 150 through the capillary 29. Therefore, air or suction can be applied to move the lead in the guide direction. The injection of the gas generates a negative pressure, by which the lead can be pulled into the guide path, and the pulled lead can be forcibly fed by the injection force of the gas. In addition, the lead guide can be equipped with a suction device, which is arranged along the lead guide direction together with the air. According to the above arrangement, suction can be applied to the lead through the insertion hole of the bonding tool, so that the lead is sucked into the insertion hole and protrudes from the end of the bonding tool. In addition, some guides may not have the characteristics of an air duct, but only serve as a guide channel for the lead.

[0111] Positioning Mark

[0112] The wire threading device 33A is provided with positioning marks 37 which help align the relative position of the guide of the wire threading device 33A with the air tensioner opening 24A, the hole in the capillary 29 and the wire clamps 26,27.

[0113] As shown in Fig. 8, the positioning mark 37 is provided with a small hole or pattern 45 to allow light from the wire bonding optical device to pass through. Since the shadow of the hole or pattern 45 on the positioning mark 37 will appear at the focal length of the optical system, the positioning mark 37 will cover a portion of the optical path 44. However, the optical device can recognize the shadow of the positioning mark 37 to confirm the actual position of the wire threading device 33A, and further determine the relative position of the wire threading device 33A and the capillary 29 (and other components).

[0114] Another method of accurately controlling the relative position of the lead threading device 33A and the capillary 29 (and other components) is to use a sensor to search for the position of the mark 37 to obtain the relative position of the lead threading device 33A and the capillary 29 (and other components). The sensor can be fixed on the lead threading device 33A. The positioning feature of the mark remains fixed relative to the capillary 29. When the bonding head (including the capillary 29 and other components) moves toward the lead threading device 33, the sensor can obtain the target threading alignment position when capturing the positioning feature on the positioning mark 37.

[0115] like Fig.9A and Fig. 9B As shown, the lead threading device 33A has an automatic moving mechanism 43, which drives the lead threading device 33A through mechanical force or pneumatic force to move it back and forth or rotate it around an axis. Fig.9A The lead threading device 33A is shown moved to a working position where the lead threading device 33 is inserted into a gap between the capillary 29, the second lead clamp 27, the first lead clamp 26 and / or the air tensioner body 25. It is important to ensure that the working position is correct, otherwise any misalignment will cause the capillary 29, the second lead clamp 27, the first lead clamp 26 and the air tensioner body 25 to collide and be damaged. In addition, if the guide of the lead threading device 33A is not aligned with the hole of the capillary 29, the first lead clamp 26, the second lead clamp 27 and the air tensioner body 25, the bonding wire threading will fail. The lead threading device 33A is used to successfully thread the bonding wire. As shown in FIG. Fig. 9B As shown, the wire threading device 33A moves backward into a parking position, at which the wire threading device 33A is further away from the capillary 29, the second wire clamp 27, the first wire clamp 26 and the air tensioner body 25, so that the capillary 29, the second wire clamp 27, the first wire clamp 26 and the air tensioner body 25 return to normal bonding operation.

[0116] Slot seals

[0117] like Fig. 10A and 10BAs shown, in order to enable the lead threading device 33A to be threaded when the capillary 29, the second lead clamp 27, the first lead clamp 26 and the air tensioner body 25 are moved to the parking position, the lead threading device 33A is provided with a series of narrow slots 46 to separate the bonding wire from the lead threading device 33. One method of reducing the adverse effects of the narrow slots 46 is to provide a soft gasket cover 39 above the narrow slots 46, because the open narrow slots will reduce the efficiency and effectiveness of the guide. Therefore, when the lead threading device 33A is threading the lead, the soft gasket cover 39 covers the narrow slots 46. After the lead is successfully threaded, the lead threading device 33A blows air to bend the soft gasket cover 39, thereby opening the narrow slots 46 and allowing the bonding wire to be separated from the lead threading device 33A when the bonding wire is retracted to the parking position.

[0118] Fig.11A and 11B Another design of opening the slot is shown. In this design, the lead threading device 33A and the guide are replaced by two components, a left guide 40 and a right guide 41. The left guide 40 and the right guide 41 are connected by a leaf spring 42, so that electromagnetic force, hydraulic force and / or pneumatic force can be slightly applied to the left guide 40, so that the left guide 40 moves away from the right guide 41, thereby opening the slot to allow the lead to be separated from the device.

[0119] Therefore, it can be seen that the three subsystems described above provide a systematic solution for retrieving, locating, capturing, guiding and ultimately threading the wire through multiple components and capillaries. The automatic wire threading equipment can guide the wire to the air flow path through the air tensioner, wire holder and wire tool (capillary) in a few seconds to resume the bonding process. After threading, the automatic wire threading system can also prepare the appropriate wire tail under the capillary to resume the bonding process. The automatic wire threading equipment is fully automatic and ready for potential Industry 4.0 unmanned factory integration. Typically, there is no need for an operator to tend to the machine and manually thread the wire after changing the winding reel or when the wire escapes from the capillary during the bonding process.

[0120] Although the present invention has been described in considerable detail with reference to certain embodiments, other versions are possible.

[0121] Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.

Claims

1. A method for automatically threading a wire in a wire bonding device, comprising the following steps: Extending a wire tail of a lead wire from a wire winding drum and positioning the wire tail in a lead wire positioning device; placing the wire tail in a straightened position of the lead positioning device; clamping the wire tail using a lead wire manipulator at the straightening position, straightening the wire tail by the lead wire manipulator at the straightening position, and transferring the straightened wire tail to a threading position using the lead wire manipulator; and At the threading position, the straightened wire tail is received by a wire threading device and threaded through a capillary of the wire bonding equipment.

2. The method according to claim 1, wherein: The lead wire positioning device is provided with a positioning hole, and the shape of the positioning hole is suitable for receiving the wire tail and guiding the wire tail to the lead wire straightening position.

3. The method according to claim 2, wherein: The positioning hole is defined by a pair of converging opposing surfaces that converge at the positioning surface at the straightened position.

4. The method according to claim 3, wherein: The positioning surface extends in a vertical direction so that the wire tail is also oriented in the vertical direction.

5. The method according to claim 3, wherein: The step of positioning the wire tail at the straightened position further includes: using a wire tail pushing device to push the wire tail extending through the positioning hole toward the positioning surface, wherein the wire tail pushing device is located in the lead positioning device.

6. The method according to claim 5, wherein: The wire tail pushing device comprises an airflow generator for generating an airflow to push the wire tail to extend through the positioning hole toward the positioning surface.

7. The method according to claim 6, wherein: The airflow generator further holds the wire tail extending through the locating hole on the locating surface.

8. The method according to claim 1, wherein: The lead handling device includes first and second pairs of lead fixtures, and the step of clamping the wire tail includes clamping the wire tail with the first and second pairs of lead fixtures adjacent to the straightened position.

9. The method according to claim 8, wherein: The step of straightening the wire tail further includes the step of moving at least one of the first and second pairs of lead retainers away from the other pair while clamping the wire tail to straighten at least a portion of the wire tail.

10. The method according to claim 8, further comprising the steps of: Excess wire is cut off the free end of the wire tail to free the straightened wire tail.

11. The method according to claim 8, wherein: Receiving the straightened wire tail at the threading location further includes drawing the straightened wire tail to the threading location through at least one of the first and second pairs of wire retainers.

12. The method according to claim 1, further comprising the steps of: When the straightened wire tail is pulled to the threading position, tension is generated in the lead wire by an air tensioner.

13. The method according to claim 1, wherein: The step of threading the straightened wire tail through the capillary further comprises the step of moving the wire threading device from a parked position to the threading position aligned with the capillary.

14. The method according to claim 12, further comprising the steps of: The straightened wire tail is guided to the capillary tube by at least one wire guide included in the wire threading device.

15. The method according to claim 14, wherein: The at least one wire guide includes a slot guide channel having an elongated slot extending along an axial length thereof, the slot being aligned with the air tensioner and the capillary tube.

16. The method according to claim 15, wherein: The lead guide includes a slot limiter operably configured to close the slot.

17. The method according to claim 16, wherein: The slot restrictor includes a flexible cover operably configured to move between a closed position and an open position to close and open the slot in use.

18. The method according to claim 17, further comprising the steps of: An air flow is generated within the wire guide to move the flexible cover between the closed position and the open position.

19. The method according to claim 16, wherein: The slot limiter includes a spring coupling the first half of the lead guide with the second half of the lead guide and is operably configured to move between a closed position and an open position to close and open the slot in use.

20. The method according to claim 14, further comprising the steps of: Position information about the lead guide relative to the capillary is obtained by imaging a location identifier coupled to the lead threading device.

21. The method according to claim 20, wherein: The location identifier comprises a visual index operably configured to be imaged by a wire bonding imaging device in use.

22. The method according to claim 20, further comprising the steps of: The wire guide is placed with a translation stage and controller to align the wire guide with the capillary.

23. A wire bonding threading apparatus configured to perform the method according to claim 1.

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