A wire bonding process and a wire bonding apparatus

Abstract

The application discloses a wire bonding process and a wire bonding device, and belongs to the technical field of semiconductor packaging. The process adopts a wire bonding device comprising a welding head, a welding table and a wire wiping platform. The welding head comprises a porcelain nozzle, a main wire clamp, an auxiliary wire clamp and a vacuum capillary. The length of the solder ball extending from the lower end surface of the porcelain nozzle is adjusted to a first preset length through the coordinated action of the main wire clamp, the auxiliary wire clamp and the vacuum capillary. The welding head drives the wire tail to be pressed and bent at a right angle on the upper surface of the wire wiping platform, and then is pressed down to the lower surface to independently form a damage part at the preset position of the wire. After bonding, the main wire clamp is lifted along the Z axis, the wire is pulled off at the damage part, and a vertical wire segment with consistent height is formed. The residual wire is collected in the internal passage of the porcelain nozzle through a damage part recovery step. The damage formation is separated from the bonding object and free of mechanical stress, is suitable for the preparation of vertical interconnection wires for ultra-thin chip and micro-pitch chip packaging, and can avoid the blockage of the porcelain nozzle and ensure the continuous operation of the equipment.

Description

Technical Field

[0001] This application relates to the field of semiconductor packaging technology, and in particular to a wire bonding process and wire bonding apparatus. Background Technology

[0002] In semiconductor packaging, wire bonding is a widely used interconnect technology used to electrically connect pads on a chip to pins on a lead frame. With the development of advanced packaging technologies, higher requirements have been placed on the precision, high consistency, and vertical interconnect capability of bonding wires, especially in the packaging applications of ultra-thin chips and micro-pitch chips, where traditional wire bonding processes are no longer sufficient to meet the demands.

[0003] In existing technologies, two methods are typically used to create a damaged section on the lead wire that is easy to break: one is to press the lead wire against the chip surface to create a weakening point. However, the mechanical force generated when the lead wire is pressed against the chip can easily cause physical damage to the chip. Moreover, the pressing position is limited by the movement trajectory of the lead wire, making it difficult to create a damaged section at a precise location on the lead wire. For ultra-thin chips, this pressing action can easily lead to chip breakage or damage to the internal circuitry. The other method is to directly cut the lead wire with tools such as scissors. However, direct cutting can easily produce burrs or irregular cross-sections at the end of the lead wire. The cutting position is also difficult to control precisely, making it impossible to create a regular and consistent damaged section at a preset location on the lead wire. This results in poor consistency in the height of the lead wire when it is subsequently pulled apart.

[0004] Furthermore, in existing technologies, damage formation is strongly correlated with the bonding step. Whether using the pressing method or the direct shearing method, damage formation usually depends on specific actions during the bonding process, resulting in severe coupling of process parameters and hindering independent optimization and control. Simultaneously, existing methods lack an effective recovery mechanism for the lead tail remaining in the ceramic nozzle after lead breakage. Residual lead tends to accumulate or clog the nozzle, affecting the continuity of subsequent threading and bonding operations, leading to increased equipment downtime and reduced production efficiency. Chinese patent CN106024653A (publication date October 12, 2016) discloses a semiconductor device manufacturing method, which cuts the bonded aluminum wire by lowering a cutting tool component and limits the termination position of the cut by using a stop member that descends with the cutting tool component to impact the lead section. However, the mechanical impact generated when the stop member impacts the lead section still acts on the lead frame, and direct cutting easily produces irregular cross-sections at the lead end. In addition, without a lead length fixing mechanism, it is impossible to achieve high-precision vertical lead preparation. Chinese patent CN122641376A (publication date August 2026) discloses an automatic wire threading method and system for wire bonding equipment, which uses the airflow generated in the air circuit device to tension the bonding wire and guide the end of the bonding wire to the operating position for gripping, straightening and passing through the bonding tool. However, this solution only solves the automation problem of the threading process, does not address the control of the formation position of the damaged part, and does not solve the problem of recovering the residual lead during the bonding process.

[0005] Chinese patent CN121908920A (publication date April 21, 2026) discloses a wire bonding method for forming a fine-pitch vertical lead interconnect structure. This method uses a wire bonding tool to press a point on the bonding wire between a capillary and a spherical lead against a portion of the spherical lead bond, creating a weakened section. The wire bonding tool is then moved to straighten this section of the bond, causing it to break at the weakened section, thus forming a vertical lead interconnect structure. This method achieves vertical lead fabrication to a certain extent, but it has limitations. The following are the core defects: First, the formation of the weakened portion relies on the bonding tool pressing the lead against the completed spherical bond. The pressure is transmitted to the chip through the bonding point, which still cannot avoid the risk of damage to the ultra-thin chip. Second, the length of the lead segment depends on the movement stroke control of the bonding tool. There is no independent length-fixing mechanism, which makes it difficult to meet the strict requirements of lead height consistency for micro-pitch chip packaging. Third, there is no residual lead recovery mechanism. After the lead breaks, the lead tail left in the ceramic nozzle can easily cause nozzle blockage, resulting in high equipment failure rate and low production efficiency.

[0006] In foreign countries, Japanese Patent Application Publication No. 2001-160566 (publication date June 12, 2001) discloses a method for forming a needle-like wire: after forming a solder ball at the end of a lead wire threaded through a capillary tube, a cutter provided in a bonding device is used to reciprocate and cut into the lead wire portion between the solder ball and the capillary tube to create scratches of equal depth. The solder ball is then bonded to an electrode pad. The lead wire is then clamped and pulled upwards by a wire clamp during the ascent of the capillary tube, causing the lead wire to be cut off at the scratch, thereby leaving a needle-like wire of a certain length on the bonded object. This solution also discloses a wire feeding mechanism that cooperates with a first wire clamp that moves up and down with the capillary tube and a fixedly provided second wire clamp. This literature established a vertical wire fabrication route of "damage formation—bonding—breakage" more than 20 years ago, but it did not disclose in detail the specific implementation method of the cutter. Furthermore, the contact between the cutter edge and the fine lead wire, typically only 20–50 μm in diameter, is a rigid compression contact, making it difficult to precisely control the indentation depth. As the cutter edge wears down, the damage depth gradually becomes uncontrollable, and tiny chips are easily generated at the compression point, posing a risk of contaminating the capillary channel and bonding area. In addition, the background technology in this literature also points out that when densely forming needle-like wires on electronic circuit components, cutting tools such as cutters are difficult to arrange.

[0007] International patent application WO 2025 / 105274 A1 (international publication date May 22, 2025) proposes an improved solution to address the problem of difficulty in forming the slit in the fine lead wire. The solution is to use a slit shear consisting of an outer blade and an inner blade, at least one of which has a tapered portion with a gradually decreasing distance between the blades along the direction of lead wire insertion. During operation, the two blades, which are in a spaced-out state, are moved toward the lead wire in a direction intersecting with the direction of lead wire extension, so that the lead wire enters between the two blades. Then, the two blades are brought close to and in contact with the lead wire, thereby forming a slit on the surface of the lead wire. Then, with the end of the lead wire bonded to the bonding object, it is clamped and pulled by a wire clamp to cut the lead wire at the slit, forming a needle-like lead wire with a length of about 100 to 500 μm. This solution improves the difficulty of forming cuts on thin leads to some extent by using a tapered guide. However, the cutting shears need to be driven by a support arm, a sliding mechanism, and an actuator to complete a complex action of "lateral insertion - closing and forming - retraction". There are many moving parts, and the timing of the actions needs to be precisely coordinated with the bonding cycle. The mechanism is complex and occupies the circumferential space of the bonding head. The two blades still make contact with the leads by the blade edge extrusion. The tapered blade edge is precise and easily damaged. After wear, the cutting depth also faces the problem of being out of control. The tiny chips generated by extrusion may also enter the capillary channel or the bonding area.

[0008] In the same field as this application, Chinese Patent CN122249087A (publication date June 19, 2026) discloses a wire bonding method and device. This solution also employs a combination of a main wire clamp and an auxiliary wire clamp, along with a vacuum capillary adsorption positioning method to precisely adjust the length of the wire extending from the end of the ceramic nozzle to a preset value, ensuring the consistency and repeatability of the vertical wire height. The damaged section is formed by an independent shutter mechanism and its blades performing directional compression damage on the wire, avoiding physical damage to the chip caused by the ceramic nozzle pressing against it. Furthermore, by setting multiple blades and their different arrangements, the depth and shape of the damaged section are controllable, ensuring that the wire breaks precisely at a predetermined position. However, this solution still has the following shortcomings: First, the blades are precision and easily damaged parts. After long-term use, the wear of the cutting edge will cause the depth and shape of the damage to gradually become out of control, requiring regular inspection, sharpening, or replacement, which increases maintenance costs and downtime. Second, the blades and leads are in rigid extrusion contact, resulting in significant stress concentration. Burrs or tiny chips are easily generated at the edges of the damaged area. Once the chips enter the internal channel of the ceramic nozzle or the bonding area, they will cause wire threading blockage or bonding contamination. Third, the shutter mechanism needs to be equipped with multiple blades that can move in opposite directions and their independent drive components. The number of moving parts is large, and the opening and closing sequence of the blades needs to be coordinated and controlled with the bonding action, resulting in a complex structure, large space occupation, and high assembly and debugging costs.

[0009] In summary, existing technologies have the following core defects: ① The method of forming the damaged part by pressing the ceramic tip together can easily cause the chip to break due to the mechanical stress generated during the pressing process, making it unsuitable for ultra-thin chip packaging; ② The method of forming the damaged part by cutting or squeezing with tools or blades, from early cutting blades to recent double-edged cutting shears and shutter mechanism blades, always relies on precision and easily damaged cutting edge components, resulting in problems such as uncontrolled edge wear, frequent maintenance, potential chip contamination, and complex mechanisms; ③ Most solutions lack independent high-precision length-fixing mechanisms and a complete residual lead wire recovery mechanism, resulting in poor lead wire height consistency, and the residual lead wire tail after breakage can easily cause ceramic tip blockage, increasing the frequency of maintenance and repair.

[0010] Therefore, there is an urgent need for a high-precision vertical interconnect wire bonding process that can precisely control lead length, independently form damaged areas, effectively recover residual leads, and is suitable for ultra-thin chips and fine-pitch packages. Summary of the Invention

[0011] This application proposes a wire bonding process and a wire bonding apparatus to solve the technical problems existing in the prior art, such as insufficient accuracy in controlling wire length, difficulty in forming damaged parts, inconvenience in recycling residual wires, and poor adaptability to ultra-thin chips and fine-pitch packaging.

[0012] To solve the above problems, the technical solution adopted in this application is: A wire bonding process includes a soldering head, a soldering station, and a wire-bonding platform. The soldering head includes a ceramic nozzle, a main wire clamp, an auxiliary wire clamp, and a vacuum capillary tube. The wire-bonding platform includes a stepped upper platform and a lower platform. The process includes the following steps: S1. Lead preparation: Extend the lead wire outwards from the ceramic nozzle to form a lead wire tail, and then melt the end of the lead wire tail to form a solder ball; S2, Lead wire length setting: Control the main wire clamp, auxiliary wire clamp and vacuum capillary to work together to adjust the length of the solder ball extending from the lower end face of the ceramic nozzle to the first preset length; S3. Damage Formation: The welding head moves down to the wire-rubbing height, and the lead tail is only higher than the upper platform of the wire-rubbing platform in the part near the ceramic nozzle. Then, it moves horizontally along the upper platform from one side, so that the lead tail bends at a right angle or near a right angle relative to the lead remaining in the ceramic nozzle. After the welding head returns to the previous timing position, the main wire clamp and the ceramic nozzle move down synchronously until the bend of the lead tail contacts the lower platform, and are further pressed down to form a damaged part at the bend of the lead tail. S4. Damaged part recovery: The damaged part is collected into the internal channel of the ceramic nozzle; S5: Wire bonding: Drive the ceramic nozzle to the bonding station and bond the solder ball to the bonding point; after the bonding is completed, the ceramic nozzle and the main wire clamp move upward along the Z-axis and adjust the length of the lead wire extending from the lower end face of the ceramic nozzle to the second preset length. S6, Bond breakage: After the main wire clamp holds the lead wire, it is pulled upward along the Z-axis, causing the lead wire to break at the damaged part, forming a vertical lead wire segment of a preset height.

[0013] As a further preferred embodiment, step S2 specifically includes: S2a, the main clamp and the auxiliary clamp are opened, and the vacuum capillary generates a vacuum suction force to attract the solder ball to contact the flared mouth of the ceramic nozzle; S2b, the auxiliary clamp closes and clamps the lead wire; the main clamp, in the open state, moves upward by a preset length synchronously with the ceramic nozzle.

[0014] As a further preferred embodiment, in step S3, the main clamp remains closed and the auxiliary clamp remains open; after the main clamp and the ceramic nozzle move down in the Z direction to the line-rubbing height, the main clamp, the auxiliary clamp, and the ceramic nozzle move synchronously along the upper platform by a set distance.

[0015] As a further preferred embodiment, step S3, in the process of forming a damaged portion at the bend of the lead tail, also includes applying ultrasonic waves to the ceramic nozzle or the wire-rubbing platform.

[0016] As a further preferred embodiment, the height difference between the upper platform and the lower platform is greater than the length of the lead tail.

[0017] As a further preferred embodiment, in conjunction with the adjustment of the position of the bonding station, steps S1 to S6 are repeated on the chip to complete the bonding of all the leads of the chip.

[0018] As a further preferred embodiment, in steps S5 and S6, the vacuum capillary maintains vacuum adsorption.

[0019] As a further preferred embodiment, in step S3, the residual area of ​​the damaged part is 1 / 3 to 1 / 2 of the cross-section of the lead wire.

[0020] As a further preferred embodiment, the specified height raised in step S6 is not less than the sum of the length of the already formed vertical lead segment, the lead length required to form the solder ball in the next ignition, and the reserved length required for the arc height of the next lead.

[0021] In addition, a wire bonding device is disclosed, including a welding head, a welding station, and a wire-rubbing platform; the welding head includes a ceramic nozzle, a main wire clamp, an auxiliary wire clamp, and a vacuum capillary tube, the main wire clamp and the ceramic nozzle are fixedly mounted on the same Z-axis drive mechanism, and their movements in the Z direction are synchronized; the wire-rubbing platform includes a stepped upper platform and a lower platform; wherein, the upper platform is used to receive the lead tail that moves with the welding head, so that the lead tail forms a right angle or near right angle bend relative to the lead remaining in the ceramic nozzle; the lower platform is used to receive the bent lead tail, so that a damage portion is formed at the bend of the lead tail when the welding head is pressed down.

[0022] Compared with the prior art, this application has the following beneficial effects: (1) By setting up an independent wire-rubbing platform, the formation of the damaged part is completed on the upper and lower surfaces of the wire-rubbing platform. The damage formation process is separated from the bonding object. No mechanical load is required on the chip, which fundamentally avoids chip breakage and internal circuit damage caused by mechanical stress in the traditional ceramic tip pressing scheme. This allows the wire bonding process to be safely applied to the packaging of ultra-thin chips. At the same time, compared with the scheme of forming the damaged part by pressing the blade with a shutter mechanism, the wire-rubbing platform is a fixed stepped structure without moving parts and easily damaged cutting edges. It does not require independent driving and opening and closing timing control. The damaged part is formed by pressing down after the lead wire is bent. There is no problem of uncontrolled damage depth caused by cutting edge wear, and no chips are generated. The structure is simple and the maintenance cost is low. (2) This application achieves precise lead length determination through the coordinated action of the main wire clamp, auxiliary wire clamp and vacuum capillary: the vacuum suction precisely positions the solder ball at the flared mouth of the ceramic nozzle to form a positioning reference, the auxiliary wire clamp holds the lead and keeps it stationary, the ceramic nozzle and the main wire clamp move upward synchronously by a first preset length, and the extension length of the lead tail is precisely controlled, which ensures the height consistency of the vertical lead segment in batch bonding from the source, and meets the strict requirements of fine pitch packaging for lead height consistency; (3) The damaged part of this application is formed by directional extrusion after being bent at a right angle at a preset position of the lead wire. The position of the damaged part and the residual cross-sectional area are precisely controllable. When it is pulled apart, only a small pulling force is needed to accurately break at the damaged part. The fracture is regular and the vertical lead wire segment has good uprightness. No subsequent shaping process is required. Moreover, the damage formation action and the bonding action are independent of each other. The process parameters are decoupled, which makes it easy to optimize and control them separately. This is beneficial to process debugging and consistency control of mass production. Attached Figure Description

[0023] To more clearly illustrate the technical solutions proposed in this application, a detailed description is provided below in conjunction with the embodiments and accompanying drawings. It should be understood that the accompanying drawings described below are merely some embodiments of this application, and those skilled in the art can make changes to these drawings within the framework of this application.

[0024] Figure 1 This is a schematic diagram of the lead preparation steps in an embodiment of this application, showing the state after the lead is inserted into the ceramic nozzle, forms a solder ball, and moves to the waiting position; Figure 2 This is a schematic diagram of the lead wire length setting step in an embodiment of this application, showing the main wire clamp and auxiliary wire clamp in the open state; Figure 3 This is a schematic diagram of the lead wire length setting steps in an embodiment of this application, showing that both the main wire clamp and the auxiliary wire clamp are open and the vacuum capillary is drawing in the lead wire; Figure 4 This is a schematic diagram of the lead preparation steps before lead damage in this application, showing the auxiliary clamp closed and the main clamp open; Figure 5 This is a schematic diagram of the lead damage process in this application, showing the main wire clamp and ceramic nozzle moving upwards, and the lead tail in a fixed length state; Figure 6 This is a schematic diagram of the lead preparation steps before lead damage in this application, showing the main clamp closed and the auxiliary clamp open. Figure 7 A schematic diagram of the lead wire damage preparation steps for this application shows the auxiliary wire clamp in the open state and the main wire clamp and ceramic nozzle in the state of moving down to the wire rubbing height. Figure 8 A schematic diagram of the lead wire damage preparation steps for this application shows the auxiliary clamp in the open state and the main clamp and ceramic nozzle reaching the wire rubbing height state. Figure 9 This is a schematic diagram of the lead wire damage process, showing the soldering head moving as a whole towards the upper surface of the wire-rubbing platform, causing the lead wire tail to bend relative to the lead wire inside the ceramic nozzle. Figure 10 This is a schematic diagram of the lead damage process, showing that after the lead tail is bent, the solder head is moved to the previous timing position. Figure 11 This is a schematic diagram of the lead wire damage process, showing the auxiliary clamp open, the main clamp closed, the main clamp and the ceramic nozzle moving down, and the lead wire contacting the lower surface of the wire-rubbing platform. Figure 12 This diagram illustrates the steps involved in completing the lead wire damage process, showing the main wire clamp and ceramic nozzle moving upwards and being raised to a specified height. Figure 13 This is a schematic diagram of the damaged part recovery process, showing the auxiliary clamp closed and the main clamp open. Figure 14 This is a schematic diagram of the damaged part recovery process, showing the main wire clamp and the ceramic nozzle moving down a specified stroke, and the damaged part being recovered to the ceramic nozzle state; Figure 15 This is a schematic diagram of the wire bonding process, showing the state where the bonding head is moved as a whole to be directly above the bonding point of the chip; Figure 16 This is a schematic diagram of the wire bonding process, showing that both the auxiliary clamp and the main clamp are in the open state. Figure 17 This is a schematic diagram of the wire bonding process, showing the main wire clamp and ceramic nozzle moving down to the designated solder joint for welding. Figure 18 This is a schematic diagram of the bond breakage process, showing the main wire clamp and ceramic nozzle being raised to a specified height. Figure 19 This is a schematic diagram of the bond breakage process, showing the main wire clamp in the closed state; Figure 20 This is a schematic diagram of the bond breakage process, showing the main wire clamp and ceramic nozzle continuing to rise, pulling the lead wire to break at the damaged area, resulting in a vertical arc-shaped state.

[0025] 1. Porcelain nozzle; 2. Lead wire; 3. Solder ball; 4. Wire rubbing platform; Upper platform 4a; Lower platform 4b; 5. Soldering station; 6. High voltage electrical device; 7. Vacuum capillary tube; 8. Auxiliary clamp; 9. Main clamp; 10. Damaged part. Detailed Implementation Example

[0026] This embodiment provides a wire bonding device for forming a vertical wire interconnect structure during semiconductor packaging, which is particularly suitable for advanced packaging applications of ultra-thin chips with a thickness of less than 25μm, wherein the spacing between the pads can be less than 30μm.

[0027] The wire bonding device used in this embodiment includes a welding head, a welding station 5, and a wire-feeding platform 4. The welding head includes a ceramic nozzle 1 and a wire clamp mechanism. The wire clamp mechanism includes a main wire clamp 9, an auxiliary wire clamp 8, and a vacuum capillary tube 7. The main wire clamp 9 and the ceramic nozzle 1 are mounted on the same Z-axis drive mechanism, and the two can move synchronously in the Z direction relative to the auxiliary wire clamp 8. The center of the ceramic nozzle 1 and the center of the wire clamp mechanism are located on the same vertical line. The wire-feeding platform 4 is located below the welding head and includes an upper platform 4a and a lower platform 4b with a stepped distribution. The height difference between the upper platform 4a and the lower platform 4b is greater than the length of the lead wire tail, thereby preventing the height difference between the upper platform 4a and the lower platform 4b from being too small. When the welding head drives the lead wire and the lead wire tail acts against the upper platform 4a, bending the lead wire tail relative to the lead wire 2 located in the ceramic nozzle 1, the lead wire tail hits the lower platform 4b, interfering with the lead wire tail and causing the lead wire tail to bend prematurely or not bend in the preset position. One end of the vacuum capillary is connected to an auxiliary clamp, and the other end is connected to a vacuum source to provide a weak adsorption or blowing force. The vacuum pressure is below -53.32 kPa.

[0028] The soldering station 5 is positioned below the ceramic nozzle 1 to support the chip to be bonded. The soldering station 5 has a heating function; depending on the different chip process requirements, it can heat the chip from room temperature to 250°C during bonding to promote the formation of intermetallic compounds between the solder balls 3 and the bonding points, thereby improving bonding strength. The soldering station 5 also has a vacuum adsorption function, firmly adsorbing the chip onto the surface of the soldering station through vacuum suction holes to prevent chip displacement during bonding. For bonding ultra-thin chips, the vacuum adsorption force of the soldering station 5 needs precise control to ensure secure fixation while avoiding excessive adsorption force that could deform or break the chip. The position of the soldering station 5 can be precisely moved in the X and Y axes to sequentially move different bonding points on the chip directly below the ceramic nozzle 1, achieving multi-position bonding. Example

[0029] This embodiment provides a wire bonding process for forming vertical wire interconnect structures during semiconductor packaging, particularly suitable for advanced packaging applications of ultra-thin chips with a thickness of less than 25μm, wherein the spacing between pads can be less than 30μm; the specific wire bonding process includes the following steps: Step S1: Lead wire preparation. This includes the following steps: S1a. Insert the lead wire 2 with a diameter of less than 18μm into the ceramic nozzle 1. Depending on the type of lead wire 2, it can be made of gold wire, alloy silver wire, palladium copper wire, etc., and different wire diameters can also be selected. The operator first manually inserts the lead wire 2 into the ceramic nozzle 1. Due to the limitations of manual operation, the length of the lead wire 2 extending from the end of the ceramic nozzle 1 varies greatly, and the manual threading error will reach 1000μm.

[0030] S1b, see Figure 1As shown, a high-voltage current is applied to the end of the lead 2 via a high-voltage electrical device 6. The output voltage of the high-voltage electrical device 6 has four modes: ultra-high, high, medium, and low. In ultra-high mode, the maximum applied voltage is approximately -5.5kV; in high mode, it is approximately -5kV; in medium mode, it is approximately -4kV; and in low mode, it is approximately -3kV. The discharge mode can be set with different currents (25-75mA) and different times (170-800μs) to achieve stepped, refined control. By adjusting the current and discharge time of the high-voltage electrical device 6, the size of the solder ball 3 can be precisely controlled to meet the requirements of subsequent bonding. After the solder ball 3 is formed, the vacuum capillary 7 provides blowing force to help maintain the lead 2 in the correct position and prevent the lead from bending.

[0031] S1c, the ceramic nozzle 1, and the main clamp 9 are in the waiting position. At this time, the main clamp 9 is closed, and the auxiliary clamp 8 is open. The height of the waiting position from the surface of the soldering station is 8000-9000μm. In this waiting position, the center of the ceramic nozzle and the center of the clamp mechanism are on the same vertical line, with a coaxiality error of less than ±1μm, providing a precise positioning reference for subsequent precise length determination and damage formation.

[0032] Step S2: Determine the length of the lead wire, including: S2a, main clamp 9 open, auxiliary clamp 8 open (e.g.) Figure 2 As shown in the diagram, the vacuum capillary tube 7 generates a vacuum force below -53.32 kPa, drawing the lead wire 2 into the ceramic nozzle 1. This, in turn, causes the solder ball 3 to move upwards, bringing it close to the flared end of the ceramic nozzle 1. Through this vacuum force, the solder ball 3 is precisely positioned at the flared end of the ceramic nozzle 1, laying the foundation for precise control of the lead wire length (see...). Figure 3 (As shown).

[0033] S2b, Auxiliary clamp 8 closes the clamping lead 2 (e.g.) Figure 4 (As shown in the diagram), the main clamp 9 is open, and the ceramic nozzle 1 moves upward synchronously with the main clamp 9, extending to the set height. Since the main clamp 9 is open, the lead wire 2 can move freely. When the ceramic nozzle 1 and the main clamp 9 move upward, the lead wire 2 extends a first preset length from the end of the ceramic nozzle 1 (see diagram). Figure 5 As shown), the extended first length forms the lead tail. Preferably, the preset first length can be set to 90~1000μm, and the preset first length is the basis for the lead length required for subsequent bonding. In this step, the auxiliary wire clamp 8 keeps the lead clamped and stationary to precisely control the exposed length of the lower end of the lead 2.

[0034] S2c, main clamp 9 closed, auxiliary clamp 8 open (see...) Figure 6 (As shown in the image), prepare for the formation of the damaged area.

[0035] Step S3: Damage formation, including: S3a, the main clamp 9 and the ceramic nozzle 1 move downwards synchronously along the Z direction. Figure 7 (as shown in the image), move to the height of the line ( Figure 8 (As shown). Preferably, the rubbing height can be set based on the height of the upper surface of the fixed rubbing platform 4, and adjusted according to the preset line arc height.

[0036] S3b. When the main wire clamp 9 and the ceramic nozzle 1 move down in the Z direction to the set wire rubbing height, the welding head moves parallel to the upper surface of the wire rubbing platform 4. Since the lead wire tail extends outside the ceramic nozzle 1, the lead wire tail is guided to bend relative to the lead wire inside the ceramic nozzle 1 during this process. Figure 9 As shown), the bending angle of the exposed portion of the lead wire 2 relative to the ceramic nozzle axis is preferably 90° or close to 90°. In the actual setting of the lead wire height, the distance between the ceramic nozzle 1 and the upper platform 4a can be selected to be no less than the diameter of the lead wire 2, thereby avoiding unintended lead wire damage during bending.

[0037] After S3c and the bending action is completed, the welding head returns horizontally along the original path to the previous timing position. Figure 10 (As shown). The main wire clamp 9 and the ceramic nozzle 1 continue to move downward synchronously along the Z direction according to the set parameters, and then contact the lower surface of the wire-rubbing platform 4. Since the lead wire 2 has been bent in the previous step, in this step, the ceramic nozzle 1 moves downward according to the set parameters, pressing the bent part of the lead wire against the lower platform surface, and performing controlled damage to the lead wire to form a damaged part 10 on the lead wire 2 (see...). Figure 11 (As shown). Further preferably, it also includes an ultrasonic generator, which can apply ultrasonic waves to the ceramic nozzle 1 (or the wire-rubbing platform 4) before or during contact between the lead and the lower platform, allowing for more effective and controllable damage to the lead. The damaged portion 10 is an incomplete cut notch, with the notch being 1 / 3 to 1 / 2 of the cross-sectional area of ​​the lead 2. By setting an independent wire-rubbing platform 4, the risk of mechanical damage to the chip is avoided compared to traditional wire rubbing. It should be noted that the parameters set in this step include the solder head's downward movement speed, the contact pressure with the lower platform, the ultrasonic power, and the vibration frequency. Furthermore, the wire-rubbing platform 4 is preferably made of a wear-resistant material, such as stainless steel, manganese steel, hard alloy, or ceramic, to ensure the consistency and stability of the damaged portion 10 during long-term continuous production.

[0038] After S3d and the damaged area are formed, the main clamp 9 and the ceramic nozzle 1 move upwards synchronously to the designated height (e.g., Figure 12(As shown). Throughout step S3, the main clamp 9 holds the lead wire in place, the auxiliary clamp 8 remains open, and the vacuum capillary 7 maintains vacuum suction to keep the lead wire 2 taut. Since the auxiliary clamp 8 is open, the lead wire 2 can move freely. When the main clamp 9 and the ceramic nozzle 1 move upwards, the lead wire between the main clamp 9 and the auxiliary clamp 8 is pulled back upwards. During this process, the remaining lead wire 2 can be drawn in by the vacuum suction generated by the vacuum capillary 7, ensuring that the lead wire 2 is fully suctioned. The suction force provided by the vacuum capillary 7 keeps the lead wire 2 under sufficient tension, meaning that the lead wire 2 between the auxiliary clamp 8 and the main clamp 9 remains taut, preventing the lead wire 2 from shaking, bending, or tangling, which could interfere with subsequent operations or even clog the ceramic nozzle 1.

[0039] Step S4: Damaged part recovery, including: S4a, auxiliary clamp 8 is closed, main clamp 9 is open. Figure 13 (as shown) S4b, the main clamp 9 and the ceramic nozzle 1 move downwards along the Z direction by a specified stroke ( Figure 14 As shown), the damaged part and the lead tail can be retracted into the ceramic nozzle 1, thereby making the solder ball 3 close to the flared opening of the ceramic nozzle 1.

[0040] Step S5: Wire bonding, including: keeping the auxiliary wire clamp 8 closed and the main wire clamp 9 open, and moving the welding head as a whole above the wire point to be welded on the product. Figure 15 As shown); the auxiliary clamp 8 opens, and then the main clamp 9 and the ceramic nozzle 1 move down synchronously to the designated solder joint for initial ball soldering (as shown). Figure 16-17 (As shown); Of course, before bonding, the soldering station 5 has fixed the ultra-thin chip to be bonded to its surface through vacuum adsorption, and moved the bonding point on the chip to directly below the ceramic nozzle 1. The soldering station 5 simultaneously turns on the heating function to make the bonding point temperature reach the target temperature. The ceramic nozzle 1, carrying the lead wire, moves downward to the bonding position, applies bonding force and ultrasonic power, and bonds the solder ball 3 to the bonding point on the chip, so that the solder ball 3 and the bonding point form a reliable intermetallic compound connection, forming the first solder point. After the lead wire bonding is completed, the ceramic nozzle 1 and the main wire clamp 9 are raised upward along the Z direction to a specified height, the damaged part 10 is released from the ceramic nozzle 1 and a tail wire is reserved. The length of this tail wire is the second reserved length. The specified height here is not less than the length of the already formed vertical lead wire segment, the length of the lead wire 2 required to form the solder ball 3 in the next arcing, and the reserved length required for the arc height of the next lead wire 2 (e.g., Figure 18 (As shown).

[0041] Step S6: Lead wire breakage, including after the ceramic nozzle 1 and main clamp 9 have risen along the Z direction in step S5, the main clamp 9 is closed, and the ceramic nozzle 1 and main clamp 9 continue to move upward along the Z direction a preset distance ( Figure 19As shown), a preset tension is applied, causing the lead wire 2 to break at the damaged portion 10, forming a vertical lead wire segment of a preset height (see...). Figure 20 (As shown). Since the damaged portion 10 has been pre-formed, only a small pulling force is needed at this point for the lead 2 to break precisely at the damaged portion 10. The resulting vertical lead segment has the required uprightness to meet the process requirements, eliminating the need for subsequent shaping steps. After breakage, the vacuum adsorption of the bonding station 5 continues to be maintained, ensuring the stable position of the bonded chip and preparing it for the next bonding. It should be noted that in steps S5 and S6, the vacuum capillary 7 maintains the vacuum adsorption of the lead.

[0042] After forming a vertical lead segment, the above steps are repeated to form an array of vertical lead interconnect structures at different locations on the chip. In each cycle, a vacuum adsorption step effectively recovers any remaining lead tails within the ceramic nozzle 1, preventing lead accumulation or blockage and ensuring the continuity and stability of subsequent operations. The bonding station 5, through precise movement along the X and Y axes, sequentially moves the next bonding point directly below the ceramic nozzle 1, achieving automated and high-precision positioning for multi-point bonding.

[0043] The method in this embodiment has been verified through mass production. The bonding yield of ultra-thin chips meets the process requirements, the lead height consistency meets the mass production standards, and the continuous trouble-free operation time of the equipment is significantly extended. It has significant technical advantages compared with traditional processes.

[0044] The above description represents specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A wire bonding process, characterized in that, A wire bonding device including a welding head, a welding station (5), and a wire bonding platform (4) is used. The welding head includes a ceramic nozzle (1), a main wire clamp (9), an auxiliary wire clamp (8), and a vacuum capillary tube (7). The wire bonding platform includes an upper platform (4a) and a lower platform (4b) with a stepped distribution. The process includes the following steps: S1. Lead preparation: Extend the lead (2) outward from the ceramic nozzle (1) to form a lead tail, and then melt the end of the lead tail to form a solder ball (3). S2, Lead wire length setting: Adjust the length of the solder ball (3) extending from the lower end face of the ceramic nozzle (1) to the first preset length; S3, Damage Formation: The main wire clamp (9) and the ceramic nozzle (1) move down synchronously to the wire rubbing height, and the lead tail is only higher than the upper platform (4a) of the wire rubbing platform in the part near the ceramic nozzle (1); then, the welding head moves from one side of the upper platform along the upper platform (4a) so that the lead tail bends at a right angle or near right angle relative to the lead left in the ceramic nozzle (1); after the welding head returns to the previous timing position, the main wire clamp (9) and the ceramic nozzle (1) move down synchronously until the bend of the lead tail contacts the lower platform, and is further pressed down so that the bend of the lead tail forms a damaged part (10). S4. Damaged part recovery: The damaged part (10) is collected into the internal channel of the ceramic nozzle (1); S5, Wire bonding: Drive the ceramic nozzle (1) to the bonding station and bond the solder ball (3) to the bonding point; after the bonding is completed, the ceramic nozzle (1) and the main wire clamp (9) move upward along the Z-axis and adjust the length of the lead wire (2) extending from the lower end face of the ceramic nozzle (1) to the second preset length. S6, Bond breakage: The main wire clamp (9) holds the lead wire (2) and pulls it upward along the Z-axis, causing the lead wire (2) to break at the damaged part (10), forming a vertical lead wire segment of a preset height.

2. The wire bonding process according to claim 1, characterized in that, Step S2 specifically includes: S2a, the main clamp (9) and the auxiliary clamp (8) are opened, and the vacuum capillary (7) generates a vacuum suction force to attract the solder ball (3) to contact the flared mouth of the ceramic nozzle (1); S2b, the auxiliary clamp (8) is closed and clamps the lead wire (2); the main clamp (9) is in the open state and moves upward by a first preset length in sync with the ceramic nozzle (1).

3. The wire bonding process according to claim 1, characterized in that, In step S3, the main clamp (9) remains closed and the auxiliary clamp (8) remains open; after the main clamp (9) and the ceramic nozzle (1) move down in the Z direction to the line-rubbing height, the main clamp (9), the auxiliary clamp (8) and the ceramic nozzle (1) move synchronously along the upper platform (4a) by a set distance.

4. The wire bonding process according to claim 1, characterized in that, In step S3, during the process of forming a damaged part (10) at the bend of the lead tail, an ultrasonic wave is also applied to the ceramic nozzle (1) or the wire-rubbing platform (4).

5. The wire bonding process according to claim 1, characterized in that, The height difference between the upper platform (4a) and the lower platform (4b) is greater than the length of the lead tail.

6. The wire bonding process according to claim 1, characterized in that, In conjunction with the position adjustment of the soldering station (5), steps S1 to S6 are repeated on the chip to complete the bonding of all the leads (2) on the chip.

7. The wire bonding process according to claim 1, characterized in that, In steps S5 and S6, the vacuum capillary (7) maintains vacuum adsorption.

8. The wire bonding process according to claim 1, characterized in that, In step S3, the residual area of ​​the damaged part (10) is 1 / 3 to 1 / 2 of the cross-section of the lead wire (2).

9. The wire bonding process according to claim 1, characterized in that, In step S6, the specified height of the lift shall not be less than the sum of the length of the already formed vertical lead segment, the lead length required to form the solder ball in the next ignition, and the reserved length required for the arc height of the next lead.

10. A wire bonding device, characterized in that, The assembly includes a welding head, a welding station (5), and a wire-rubbing platform (4). The welding head includes a ceramic nozzle (1), a main wire clamp (9), an auxiliary wire clamp (8), and a vacuum capillary tube (7). The main wire clamp (9) and the ceramic nozzle (1) are fixedly installed on the same Z-axis drive mechanism, and their movements in the Z direction are synchronized. The wire-rubbing platform (4) includes a stepped upper platform (4a) and a lower platform (4b). The upper platform (4a) is used to receive the lead wire tail that moves with the welding head, so that the lead wire tail forms a right angle or near right angle bend relative to the lead wire (2) remaining in the ceramic nozzle (1). The lower platform (4b) is used to receive the bent lead wire tail, so that a damaged part (10) is formed at the bend of the lead wire tail when the welding head is pressed down.

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