A wire bonding method and a wire bonding apparatus

Abstract

This invention provides a wire bonding method and device, relating to the field of semiconductor packaging technology. By cooperating with a main wire clamp and an auxiliary wire clamp, combined with the adsorption positioning of a vacuum capillary, the length of the lead extending from the end of the ceramic nozzle can be precisely adjusted to a preset value. This effectively solves the problem of inconsistent lead lengths caused by manual threading, ensuring the consistency and repeatability of the vertical lead height, meeting the requirements for lead height consistency in micro-pitch chip packaging. An independent shutter mechanism and its blades damage the lead, avoiding the risk of physical damage to the chip caused by the ceramic nozzle pressing against it, making it particularly suitable for ultra-thin chip packaging. Simultaneously, by setting multiple blades and their different arrangements, regular and consistent damage areas can be formed at precise locations on the lead, with controllable damage depth and shape, ensuring precise breakage of the lead at a predetermined position.

Description

Technical Field

[0001] This application relates to the field of semiconductor packaging technology, and in particular to a wire bonding method and a 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 methods 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.

[0005] Domestic patent application CN 111668124 A discloses a method for forming a vertical interconnect portion of a bonding lead. This method uses a ceramic nozzle to press against the substrate and laterally translate, deforming the lead to form a weakened portion, which improves the straightness of the vertical lead to some extent. However, this solution has the following core drawbacks: First, damage formation depends on the ceramic nozzle pressing against the substrate / chip, which cannot avoid the risk of damage to ultra-thin chips. Second, for advanced packaging applications of ultra-thin chips and micro-pitch chips, forming vertical leads often requires a large operating space or may apply mechanical force to the chip, making it difficult to simultaneously meet the low stress requirements of ultra-thin chips and the high precision requirements of micro-pitch chips. Third, there is no residual lead recovery mechanism; after a lead breaks, the lead tail remaining in the ceramic nozzle can easily cause nozzle blockage, leading to a high equipment failure rate and low production efficiency.

[0006] In summary, existing technologies generally suffer from the following three core defects: ① Damage formation depends on the ceramic nozzle pressing against the substrate / chip, and the mechanical stress generated during the pressing process can easily cause the chip to break, making it unsuitable for ultra-thin chip packaging; ② Low lead length accuracy, lack of an independent high-precision length-fixing mechanism, and generally large lead height errors, which cannot meet the stringent requirements for lead height consistency in micro-pitch packaging; ③ No perfect residual lead recovery mechanism, and the residual lead tail after the lead is pulled off can easily cause the ceramic nozzle to become clogged, thereby increasing the frequency of maintenance and repair.

[0007] Therefore, there is an urgent need for a high-precision vertical interconnect wire bonding method 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

[0008] This invention proposes a wire bonding method and a wire bonding device 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.

[0009] To solve the above problems, the technical solution adopted by the present invention is as follows: This invention provides a wire bonding method, comprising the following steps: S1. Lead wire preparation: Insert the lead wire into the ceramic nozzle and melt it at the lower end of the lead wire to form a solder ball; drive the ceramic nozzle to move the lead wire to the preset waiting position. The axis of the ceramic nozzle, the axis of the center hole of the shutter mechanism and the axis of the wire hole of the wire clamp mechanism are set in the same line. S2, Lead Wire Length Setting: Controls 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 preset first length; the vacuum capillary and auxiliary wire clamp are integrated and have the function of switching between vacuum adsorption and positive pressure blowing. S3. Damage formation: At least two blades of the shutter mechanism, which are independently set between the ceramic nozzle and the soldering station, move towards each other to perform directional compression damage on the lead wire extending from the ceramic nozzle, forming an incompletely cut damage section on the lead wire, with the damage section located between the solder ball and the lower end face of the ceramic nozzle. S4. Damaged part recovery: The auxiliary wire clamp holds the lead wire and the main wire clamp opens. The ceramic nozzle moves downward along the Z-axis for a preset second length to collect the damaged part into the internal channel of the ceramic nozzle. The remaining lead wire is recovered into the ceramic nozzle through the vacuum adsorption effect of the vacuum capillary. 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 auxiliary wire clamp opens, and the ceramic nozzle and the main wire clamp move upward along the Z-axis to adjust the length of the lead wire extending from the lower end face of the ceramic nozzle to the preset third length. S6, Bond Breakage: The main wire clamp holds the lead wire, and drives the ceramic nozzle and main wire clamp to pull 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.

[0010] Furthermore, the position adjustment of the bonding station is repeated on the chip using steps S1 to S6 to complete all wire bonding of the substrate.

[0011] Furthermore, in steps S5 and S6, the vacuum capillary maintains vacuum adsorption.

[0012] Furthermore, in step S3, the residual thickness of the damaged portion is 1 / 3 to 1 / 2 of the lead diameter.

[0013] Furthermore, the shutter mechanism includes at least two blades, which are arranged radially symmetrically along the lead wire or distributed in a circumferential array, and the blades are made of cemented carbide, diamond, or ceramic materials.

[0014] Furthermore, the blade edge is V-shaped, arc-shaped, or trapezoidal, and a corresponding damaged portion is formed on the lead wire.

[0015] Furthermore, 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 auxiliary wire clamp is set in a fixed position, and its height remains constant during the bonding process.

[0016] Further, step S2 specifically includes: S2a, the main clamp opens, and the vacuum capillary generates a vacuum suction force to attract the solder ball to contact the flared end of the ceramic nozzle; S2b: The auxiliary clamp closes and holds the lead wire, and moves upward by a preset first length while the main clamp is open; S2c, main clamp closed, auxiliary clamp open, main clamp and ceramic nozzle move synchronously along the Z direction to the cutter position.

[0017] Furthermore, the preset third length is equal to the sum of the length of the cut lead wire, the lead wire length required to form the solder ball in the next ignition, the reserved length required for the arc height of the next lead wire, and the fixed safety length to prevent the blade of the shutter mechanism from colliding with the tip of the ceramic nozzle.

[0018] Furthermore, this application discloses a wire bonding apparatus for performing a wire bonding method, comprising: A ceramic nozzle is used to thread the lead wire and carry its movement. The wire clamp mechanism includes a main wire clamp, an auxiliary wire clamp, and a vacuum capillary tube integrated with the auxiliary wire clamp. The vacuum capillary tube has the function of switching between vacuum adsorption and positive pressure blowing. The shutter mechanism, independently located between the ceramic nozzle and the soldering station, includes at least two blades that can move in opposite directions, used to perform directional extrusion damage on the lead wire to form a damaged portion on the lead wire; The drive mechanism is used to drive the ceramic nozzle, main cable clamp, and shutter mechanism to perform corresponding movements.

[0019] Compared with the prior art, the present invention has the following beneficial effects: This invention, through the cooperation of a main wire clamp and an auxiliary wire clamp, combined with the adsorption positioning of a vacuum capillary, can precisely adjust the length of the lead extending from the end of the ceramic nozzle to a preset value. This effectively solves the problem of inconsistent lead lengths caused by manual threading, ensuring the consistency and repeatability of the vertical lead height, meeting the lead height requirements of micro-pitch chip packaging. An independent shutter mechanism and its blades damage the lead, avoiding the risk of physical damage to the chip caused by the ceramic nozzle pressing against it, making it particularly suitable for ultra-thin chip packaging. Simultaneously, by setting multiple blades and their different arrangements, regular and consistent damage sections can be formed at precise locations on the lead, with controllable damage depth and shape, ensuring precise breakage of the lead at the predetermined position. Furthermore, through the vacuum adsorption function of the vacuum capillary, the lead tail remaining in the ceramic nozzle after breakage can be effectively recovered, avoiding the problem of residual lead accumulation or blockage, reducing equipment downtime, and improving continuous production efficiency and yield. Attached Figure Description

[0020] To more clearly illustrate the technical solution proposed by the present invention, 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 the present invention, and those skilled in the art can make changes to these drawings under the concept of the present invention.

[0021] Figure 1 This is a schematic diagram of the lead wire passing through the ceramic nozzle provided by the present invention; Figure 2 This is a schematic diagram of the lead preparation steps according to an embodiment of the present invention, showing the state after the lead is inserted into the ceramic nozzle, forms a solder ball, and moves to the waiting position; Figure 3 This is a schematic diagram of the lead wire length setting step in an embodiment of the present invention, showing the state in which the main wire clamp, auxiliary wire clamp, and vacuum capillary work together to adjust the lead wire extension length; Figure 4 This is a schematic diagram of the lead preparation steps before lead damage according to the present invention, showing the state of the auxiliary clamp being closed and the main clamp being open; Figure 5 This is a schematic diagram of the steps for forming a damaged portion on the lead wire in this invention, showing the state of the lead wire entering the shutter mechanism; Figure 6 This is a schematic diagram showing the state of the damaged portion formed by the lead wire in this invention; Figure 7 This is a schematic diagram showing the state of the damaged part of the ceramic nozzle being returned to the ceramic nozzle according to the present invention, indicating that the auxiliary clamp is closed and the main clamp is open. Figure 8 This is a schematic diagram of the vacuum capillary tube of the present invention drawing the lead wire into the ceramic nozzle, showing the auxiliary wire clamp open and the main wire clamp open. Figure 9 This is a schematic diagram of the ceramic nozzle of the present invention about to move toward the bonding site, showing the state of the ceramic nozzle and the shutter mechanism; Figure 10 This is a schematic diagram of the bond breakage state of the present invention.

[0022] 1. Ceramic nozzle; 2. Lead wire; 3. Solder ball; 4. Shutter mechanism; 5. Soldering station; 6. High voltage device; 7. Vacuum capillary tube; 8. Auxiliary clamp; 9. Main clamp; 10. Damaged part. Detailed Implementation

[0023] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0024] This embodiment provides a wire bonding method and wire bonding apparatus for forming a vertical lead 2 interconnect structure during semiconductor packaging. It is particularly suitable for advanced packaging applications of ultra-thin chips with a thickness of 25μm or more, wherein the spacing between pads can be 30μm or more.

[0025] The wire bonding device used in this embodiment includes a ceramic nozzle 1, a wire clamp mechanism, a shutter mechanism 4, and a bonding station 5. 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 their movement in the Z direction is always synchronized. The auxiliary wire clamp 8 is fixed in position, and its height remains constant during the wire bonding process. The shutter mechanism 4 is located between the ceramic nozzle 1 and the auxiliary wire clamp 8, with its center aligned vertically with the center of the ceramic nozzle 1 and the center of the wire clamp mechanism. One end of the vacuum capillary tube 7 is connected to the auxiliary wire clamp 8, and the other end is connected to a vacuum source to provide a weak suction or blowing force; the vacuum pressure is below -50 kPa.

[0026] 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 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.

[0027] The wire bonding method in this embodiment specifically 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 (see...). Figure 1 (As shown) Depending on the type of lead 2, it can be made of different materials and have different diameters, such as gold wire, alloy silver wire, palladium copper wire, etc. The operator first manually inserts lead 2 into the ceramic nozzle 1. Due to the limitations of manual operation, the length of lead 2 extending from the end of the ceramic nozzle 1 varies greatly, and the manual threading error will reach 1000μm.

[0028] S1b, see Figure 2 As shown, a high-voltage current is applied to the end of the lead 2 via a high-voltage electrical device 6. 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, approximately -5kV; in medium mode, approximately -4kV; and in low mode, 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 it from bending.

[0029] S1c. Move the ceramic nozzle 1 to the waiting position, which is 8000-9000μm above the surface of the soldering station 5. In this waiting position, the center of the ceramic nozzle 1, the center of the shutter mechanism 4, and the center of the wire 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.

[0030] Step S2: Determine the length of the lead wire S2a, the main clamp 9 opens, and the vacuum capillary 7 of the auxiliary clamp 8 generates a vacuum suction force below -53.32 kPa, drawing in the solder ball 3 and bringing it close to the flared end of the ceramic nozzle 1. Through this vacuum suction, 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 length 2 (see...). Figure 3 (As shown).

[0031] S2b, the auxiliary clamp 8 closes to hold the lead wire 2, the main clamp 9 opens, and the ceramic nozzle 1 and the main clamp 9 move upward synchronously for a preset first length, so that the lead wire 2 protrudes from the end of the ceramic nozzle 1 at the preset first length (see...). Figure 4 (As shown). The preset first length can be set to 90~1000μm. Since the main clamp 9 is in the open state, the lead 2 can move freely. When the ceramic nozzle 1 and the main clamp 9 move upward, the lead 2 is pulled out from the end of the ceramic nozzle 1. The preset first length is the basis for the length of the lead 2 required for subsequent bonding. In this step, the auxiliary clamp 8 remains stationary to precisely control the exposed length of the lead 2.

[0032] S2c: Main cable clamp 9 is closed, auxiliary cable clamp 8 is open, and main cable clamp 9 and ceramic nozzle 1 move downwards synchronously along the Z direction until they reach the cutting position. The descent height of the cutting position is based on the blade of the fixed shutter mechanism 4 and is actually adjusted according to the preset arc height. In this step, since main cable clamp 9 is closed, lead wire 2 is held by main cable clamp 9. Therefore, lead wire 2 moves together with main cable clamp 9 and ceramic nozzle 1. By precisely controlling the moving distance, the length of lead wire 2 extending from the end of ceramic nozzle 1 can be accurately adjusted to the required value (see...). Figure 5 (As shown) Step S3: Damage Formation When shutter mechanism 4 closes, the blade driving shutter mechanism 4 damages lead wire 2, forming a damaged portion 10 on lead wire 2 (see...). Figure 5 (As shown). In this embodiment, the shutter mechanism 4 includes two blades symmetrically arranged on both sides of the lead wire 2. When the shutter mechanism 4 is closed, the two blades move towards each other, forming a V-shaped notch symmetrically on the lead wire 2 as a damage portion 10 (see...). Figure 6 (As shown). The damaged portion 10 is an incomplete cut notch, less than 1 / 2 the diameter of the lead 2. The formation of the damaged portion 10 is independent of the movement of the ceramic nozzle 1 and does not depend on the action of the ceramic nozzle 1 pressing against the chip, thus avoiding the risk of mechanical damage to the chip.

[0033] As an alternative implementation, the shutter mechanism 4 may also include three blades evenly distributed around the lead wire 2 in a circular array. When the shutter mechanism 4 is closed, each blade moves synchronously towards the center, forming three symmetrical V-shaped notches around the lead wire 2, giving the damaged portion 10 a star-shaped cross-section. This multi-blade configuration can more evenly weaken the strength of the lead wire 2, ensuring the flatness of the fracture surface upon breakage.

[0034] The cutting edge of the blade is coated with diamond to ensure the consistency and stability of the formation of the damage area 10 during long-term continuous production. Alternatively, the cutting edge can be arc-shaped, V-shaped, or trapezoidal to create corresponding indentations or notches on the lead wire 2. The blade can also be made of other wear-resistant materials, such as stainless steel, manganese steel, cemented carbide, or ceramics, to ensure the consistency and stability of the formation of the damage area 10 during long-term continuous production.

[0035] Of course, more than three blades can be arranged in a radial circumferential array along the lead wire 2, thereby forming a more precise damage section 10 on the lead wire 2, so that the lead wire 2 forms a more uniform and flat cross-section when it breaks later.

[0036] Step S4: Recovery and bonding of damaged portion 10 With S4a, auxiliary clamp 8 closed and main clamp 9 open, the ceramic nozzle 1 moves downwards along the Z direction to return the damaged part 10 back into the ceramic nozzle 1 (see...). Figure 7 (As shown). With the main wire clamp 9 open, the lead wire 2 can move freely. When the ceramic nozzle 1 moves downward, the damaged part 10 is precisely returned to the interior of the ceramic nozzle 1, preparing for subsequent bonding.

[0037] S4b, with the auxiliary clamp 8 open, the remaining lead wire 2 is drawn into the ceramic nozzle 1 by the vacuum suction force generated by the vacuum capillary tube 7 (see...). Figure 8 (As shown). This step ensures that the lead wire 2 inside the ceramic nozzle 1 is fully attracted, preventing excess lead wire 2 from interfering with subsequent operations or even clogging the ceramic nozzle 1. The suction force provided by the vacuum capillary tube 7 keeps the lead wire 2 taut from the auxiliary wire clamp 8 to the ceramic nozzle 1, preventing the lead wire 2 from shaking or bending.

[0038] S4c, shutter mechanism 4 opens, ceramic nozzle 1 moves downward along the Z direction to the bonding position for bonding (see...). Figure 9-10 (As shown). It should be noted that after the shutter mechanism 4 opens, the blades retract to their original positions, forming a channel between the blades sufficient for the ceramic nozzle to pass through smoothly. Before bonding, the bonding station 5 has fixed the ultra-thin chip to be bonded onto its surface using vacuum adsorption, and moved the bonding point on the chip directly below the ceramic nozzle 1. The bonding station 5 simultaneously activates its heating function to bring the bonding point temperature to the target temperature. The ceramic nozzle 1, carrying the lead wire 2, 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 joint.

[0039] Step S5: Break the lead wire After bonding is complete, the ceramic nozzle 1 rises along the Z direction. This rising length is the preset third length, which is equal to the length of the already cut lead wire 2, the length of lead wire 2 required for the next arc to form the solder ball 3, the reserved length for the arc height of the next lead wire 2, and the fixed safety length to prevent the blade of the shutter mechanism 4 from colliding with the tip of the ceramic nozzle 1. This precise calculation of the rising length ensures the consistency of the lead wire 2 length and the reliability of the operation in subsequent operations. After the rising is completed, the main wire clamp 9 is closed, and the ceramic nozzle 1 and the main wire clamp 9 continue to move upwards along the Z direction a preset distance, applying a preset tension to break the lead wire 2 at the damage section 10, forming a vertical lead wire segment of a preset height (see...). Figure 10 (As shown). Since the damaged portion 10 has been pre-formed, only a small pulling force is needed to precisely break the lead 2 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 the breakage, the vacuum adsorption of the bonding station 5 continues to maintain, ensuring the stable position of the bonded chip and preparing it for the next bonding.

[0040] After forming a vertical lead segment, the above steps are repeated to form an array of vertical lead interconnect structures 2 at different locations on the chip. In each cycle, a vacuum adsorption step effectively recovers the tail section of lead 2 remaining in the ceramic nozzle 1, avoiding lead 2 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.

[0041] The method in this embodiment has been verified through mass production. The bonding yield of ultrathin chips meets the process requirements, the high consistency of lead 2 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.

[0042] Example 1: Symmetrical arrangement of dual blades The system employs a symmetrical arrangement of two blades with V-shaped cutting edges. The diameter of lead 2 is within an optimal range, the extension length of lead 2 meets process requirements, the pulling speed is controlled within a preset range, and the vacuum adsorption pressure is set to a negative value. Experiments show that the height error of lead 2 is controlled within a small range, the breakage rate is lower than the process threshold, ultra-thin chip bonding is free of breakage, and the continuous operation time of the equipment is significantly extended without clogging.

[0043] Example 2: Three-blade circumferential arrangement scheme A three-blade circular array is used, with the blades being arc-shaped. The diameter of lead 2 is within the preferred range, the lead 2 extension length meets the process requirements, the lifting speed is controlled within a preset range, and the vacuum adsorption pressure is set to a negative value. Experiments show that the height error of lead 2 is controlled within a small range, the breakage rate is lower than the process threshold, ultra-thin chip bonding is free of breakage, and the continuous operation time of the equipment is significantly extended without clogging.

[0044] Example 3: Four-blade circumferential arrangement scheme A four-blade circular array is used, with trapezoidal blades. The diameter of lead 2 is within the preferred range, the lead 2 extension length meets the process requirements, the lifting speed is controlled within a preset range, and the vacuum adsorption pressure is set to a negative value. Experiments show that the height error of lead 2 is controlled within a small range, the breakage rate is lower than the process threshold, the ultra-thin chip bonding is free of breakage, and the continuous operation time of the equipment is significantly extended without clogging.

[0045] Comparative Example: Existing Ceramic Nozzle 1 Pressing Solution Using the ceramic nozzle 1 pressing method disclosed in the existing technology CN 111668124 A, and using the lead wire 2 of the same diameter as in Example 1, the experiment showed that the height error of the lead wire 2 was large, the failure rate of pull-out was high, the chip breakage rate exceeded the allowable range of the process, and the continuous operation time of the equipment was short before the ceramic nozzle 1 became blocked and needed to be stopped for cleaning.

[0046] The above description describes specific embodiments of the present invention, but the scope of protection of the present invention 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 the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A wire bonding method, characterized in that, Includes the following steps: S1. Lead wire preparation: Insert the lead wire (2) into the ceramic nozzle (1) and melt it at the lower end of the lead wire (2) to form a solder ball (3); drive the ceramic nozzle (1) to move the lead wire (2) to the preset waiting position. The axis of the ceramic nozzle (1), the axis of the center hole of the shutter mechanism (4) and the axis of the wire hole of the wire clamp mechanism are set in the same line. S2, Lead wire length setting: Control the main wire clamp (9), auxiliary wire clamp (8) and vacuum capillary tube (7) to work together to adjust the length of the solder ball (3) extending from the lower end face of the ceramic nozzle (1) to a preset first length; the vacuum capillary tube (7) and the auxiliary wire clamp (8) are integrated and have the function of switching between vacuum adsorption and positive pressure blowing. S3, Damage Formation: Drive at least two blades of the shutter mechanism (4) independently disposed between the ceramic nozzle (1) and the soldering station (5) to move towards each other, and perform directional extrusion damage on the lead wire (2) extending from the ceramic nozzle (1), forming an incompletely cut damage portion (10) on the lead wire (2), the damage portion (10) being located between the solder ball (3) and the lower end face of the ceramic nozzle (1); S4, Damaged part recovery: Control the auxiliary wire clamp (8) to clamp the lead wire (2) and the main wire clamp (9) to open, drive the ceramic nozzle (1) to move downward along the Z axis by a preset second length, and store the damaged part (10) into the internal channel of the ceramic nozzle (1). The remaining lead wire (2) is recovered into the ceramic nozzle (1) through the vacuum adsorption effect of the vacuum capillary (7). 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 auxiliary wire clamp (8) is opened and the ceramic nozzle (1) and the main wire clamp (9) are driven to move upward along the Z-axis to adjust the length of the lead wire (2) extending from the lower end face of the ceramic nozzle (1) to a preset third length; S6, Bond breakage: The main wire clamp (9) holds the lead wire (2), drives the ceramic nozzle (1) and the main wire clamp (9) to pull upward along the Z-axis, so that the lead wire (2) breaks at the damaged part (10) to form a vertical lead wire segment of a preset height.

2. The wire bonding method 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 substrate.

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

4. The wire bonding method according to claim 1, characterized in that, In step S3, the residual thickness of the damaged part (10) is 1 / 3 to 1 / 2 of the diameter of the lead wire (2).

5. The wire bonding method according to claim 1, characterized in that, The shutter mechanism (4) includes at least two blades, which are arranged radially symmetrically or in a circular array along the lead wire (2), and the blades are made of cemented carbide, diamond or ceramic material.

6. The wire bonding method according to claim 1, characterized in that, The blade has a V-shaped, arc-shaped, or trapezoidal cutting edge, and a corresponding damage portion (10) is formed on the lead wire (2).

7. The wire bonding method according to claim 1, characterized in that, 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 auxiliary wire clamp (8) is set in a fixed position and its height remains constant during the bonding process.

8. The wire bonding method according to claim 1, characterized in that, Step S2 specifically includes: S2a, the main clamp (9) is 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), and moves upward by the preset first length while the main clamp (9) is open; S2c, the main clamp (9) is closed, the auxiliary clamp (8) is opened, and the main clamp (9) and the ceramic nozzle (1) move synchronously along the Z direction to the cutting position.

9. The wire bonding method according to claim 1, characterized in that, The preset third length is equal to the sum of the length of the cut lead wire (2), the length of the lead wire (2) required to form the solder ball (3) in the next ignition, the reserved length required for the arc height of the next lead wire (2), and the fixed safety length to prevent the blade of the shutter mechanism (4) from colliding with the tip of the ceramic nozzle (1).

10. A wire bonding apparatus for performing the wire bonding method as described in any one of claims 1-7, characterized in that, include: A ceramic nozzle (1) is used to thread the lead wire (2) and carry the lead wire (2) in motion; The wire clamp mechanism includes a main wire clamp (9), an auxiliary wire clamp (8), and a vacuum capillary (7) integrated with the auxiliary wire clamp (8). The vacuum capillary (7) has the function of switching between vacuum adsorption and positive pressure blowing. The shutter mechanism (4) is independently set between the ceramic nozzle (1) and the soldering station (5), and includes at least two blades that can move in opposite directions, for directional extrusion damage to the lead wire (2) to form a damaged part (10) on the lead wire (2); the drive mechanism is used to drive the ceramic nozzle (1), the main wire clamp (9) and the shutter mechanism (4) to perform corresponding movements.

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