Integrated dismounting and packaging device for metal cover plate of BGA (Ball Grid Array) device

Abstract

The invention relates to the field of semiconductors, and particularly discloses a BGA device metal cover plate integrated dismounting and packaging device, which comprises a device main body, and is characterized in that an anti-static module, a precise preheating module, a flexible sand line degumming module and a device positioning module are integrated on the device main body; the anti-static module comprises an anti-static wrist interface arranged on the surface of the device main body and a static contact ring arranged around the device placing area, and the static contact ring and the anti-static wrist interface are respectively grounded; the precise preheating module is located under the device placement area and comprises a controller, a plurality of constant-temperature heating plates and a plurality of temperature sensors, the temperature sensors form a temperature acquisition array, and the temperature acquisition array and the constant-temperature heating plates are electrically connected with the controller; the flexible sand line degumming module comprises four groups of sand line assemblies which are symmetrically arranged around the device placing area; by adopting the technical scheme of the invention, flexible and accurate photoresist removal can be realized, and damage-free disassembly of the device is realized.

Description

Technical Field

[0001] This invention relates to the semiconductor field, and in particular to an integrated device for removing and packaging metal cover plates of BGA devices. Background Technology

[0002] BGA (Ball Grid Array) devices are widely used in high-end electronic devices (such as smartphones, servers, and industrial control modules) due to their high integration and small package size. These devices are typically packaged and protected with a metal cover. The metal cover is fixed to the chip and heat conduction is achieved through thermal adhesives (such as silicone-based thermally conductive adhesives) and sealants (such as epoxy resin adhesives). At the same time, a solder ball array is provided on the bottom of the package substrate to realize the electrical connection between the device and external circuits.

[0003] In the production and debugging of BGA devices, surface metal remarking, or rework and reuse scenarios, it is often necessary to remove the metal cover plate to replace the cover plate or to repair the packaging structure. Currently, most methods for removing metal cover plates involve destructive operations, including: 1) Mechanical grinding, which involves directly grinding the metal cover plate with a grinding wheel or sandpaper until it is completely removed. This method easily generates grinding debris that contaminates the chip surface, and the mechanical stress during the grinding process can cause deformation of the packaging substrate and detachment of the solder ball array, making it impossible to guarantee the subsequent reuse of the device; 2) High-temperature melting method, which involves heating the device in a high-temperature oven (usually at a temperature exceeding 150°C) to melt the adhesive layer. However, if the temperature is not properly controlled, the solder ball array (such as tin-lead solder balls with a melting point of about 183°C) can easily become close to a molten state, damaging the connection stability between the solder balls and the substrate. At the same time, the high temperature can cause thermal stress damage to the internal circuitry of the chip; 3) Forceful disassembly method, which involves directly prying the metal cover plate with tools such as tweezers and pry bars. This method generates instantaneous impact force, causing the bonding layer between the chip and the substrate to break, the metal cover plate to deform, and even causing electrostatic discharge (ESD) damage to the chip, completely losing the reusability of the device.

[0004] To address the aforementioned issues, Chinese patent publications CN111874862A and CN104966689A (due to excessive cost) disclose similar technologies. However, in practical applications, both suffer from insufficient thermal control precision, failing to achieve a balance between the "softened adhesive layer" and the "protective solder balls / chip." This makes them prone to device damage due to localized high temperatures or temperature fluctuations. The main reason is that during the overall heating of the target device, natural heat dissipation or the integrated nature of the heating device itself can lead to excessively high local temperatures, causing damage. Furthermore, operations such as grinding and prying rely on manual experience, making it impossible to adjust the force according to the degree of adhesive softening. This can easily result in excessive force damaging the chip or substrate, or insufficient force leaving adhesive residue.

[0005] Therefore, there is an urgent need for a flexible and precise adhesive removal device for integrated metal cover removal and packaging of BGA devices to meet the requirements of non-destructive removal and subsequent reuse of devices. Summary of the Invention

[0006] This invention provides an integrated device for removing and packaging BGA device metal cover plates, which can flexibly and precisely remove adhesive and achieve device removal without damage.

[0007] To solve the above-mentioned technical problems, this application provides the following technical solution: A BGA device metal cover integrated removal and packaging device includes a device body, which integrates an anti-static module, a precision preheating module, a flexible sanding line adhesive removal module, and a device positioning module. The anti-static module includes an anti-static wrist interface disposed on the surface of the device body, and an electrostatic contact ring disposed around the device placement area, wherein the electrostatic contact ring and the anti-static wrist interface are respectively grounded. The precision preheating module is located directly below the device placement area and includes a controller, several constant-temperature heating plates and several temperature sensors. The temperature sensors form a temperature acquisition array, and the temperature acquisition array and the constant-temperature heating plates are electrically connected to the controller. The flexible sanding wire de-adhesive module includes four sets of sanding wire assemblies symmetrically arranged around the device placement area. Each set of sanding wire assemblies includes a rotation drive end, a resin sanding wire, and a tension adjustment unit. The resin sanding wire is wound around the rotation drive end and the tension adjustment unit. The rotation drive end is used to drive the resin sanding wire to move along its axial direction. The device positioning module includes four independently adjustable clamping units, which are distributed outside the device placement area and have an elastic buffer layer on the clamping surface.

[0008] The basic principle and beneficial effects of the solution are as follows: The anti-static wrist strap interface and the electrostatic contact ring surrounding the device placement area form a conductive path with the ground. When the operator wears the anti-static wrist strap, the static charge generated by the human body movement can be quickly conducted to the wrist through the electrostatic contact ring and conducted to the ground. At the same time, the electrostatic contact ring surrounding the device placement area contacts the BGA device. The static charge generated on the surface of the BGA device due to friction and induction can be conducted to the ground through the electrostatic contact ring, blocking the breakdown path of static electricity to the chip circuit from the source.

[0009] A temperature acquisition array composed of temperature sensors uniformly covers the device placement area, which can collect temperature data of different areas of BGA device from all directions and transmit it to the controller in real time. The controller analyzes the temperature distribution differences and dynamically adjusts the heat output of the constant temperature heating plate to ensure that the heating energy is accurately applied to the heat dissipation adhesive and sealant area between the metal cover and the chip, so as to achieve uniform softening of the adhesive layer.

[0010] Four sets of sanding wire assemblies are symmetrically distributed around the device placement area. The rotating drive end drives the resin sanding wire to make uniform frictional movement along the gap between the metal cover plate and the chip, so as to achieve flexible and precise glue removal.

[0011] Four independently adjustable clamping units surround and clamp the BGA device packaging substrate from the outside of the device placement area. By independently adjusting to adapt to devices of different sizes, the elastic buffer layer on the clamping surface can buffer the clamping force and avoid scratches on the substrate caused by direct metal contact, ensuring the device is in a stable position during removal.

[0012] The temperature acquisition array accurately captures temperature differences on the device surface through multi-point synchronous temperature measurement. Based on this data, the controller dynamically adjusts the constant-temperature heating plate to minimize temperature uniformity deviation in the adhesive layer area, preventing localized high temperatures that could cause the solder ball array to melt or the adhesive layer to soften unevenly. Simultaneously, the multi-sensor layout reduces the response delay of temperature acquisition, improving the heating system's response speed to temperature fluctuations and ensuring the adhesive layer remains in a stable softened state, providing a prerequisite for non-destructive removal.

[0013] The resin sanding lines are flexible and can be precisely embedded in the tiny gaps between the metal cover and the chip, avoiding mechanical scratches on the chip surface. In addition, the four symmetrically distributed sanding line components work simultaneously, ensuring that the descaling force is evenly distributed around the metal cover, preventing excessive force on one side from causing the cover to tilt or the chip to shift, further ensuring that the removal process is damage-free.

[0014] The multi-sensor parallel acquisition mode of the temperature acquisition array, combined with the controller's real-time data processing algorithm, reduces the response delay of heating regulation and shortens the time for the adhesive layer to rise from room temperature to the target softening temperature. Through the fusion analysis of multi-point temperature data, the temperature acquisition array achieves high accuracy in identifying the softening state of the adhesive layer. Four independently adjustable clamping units can accommodate BGA devices of different sizes, meeting diverse removal and handling needs without requiring fixture changes.

[0015] In summary, this invention achieves uniform heating, flexible and precise adhesive removal, and damage-free disassembly.

[0016] Furthermore, there are five constant temperature heating plates, which correspond to the four sides and the central adhesive layer distribution area under the metal cover of the BGA device, and each constant temperature heating plate independently heats a heating sub-area.

[0017] Furthermore, the upper surface of the constant temperature heating plate is covered with a layer of polyimide insulation, and the edge of the constant temperature heating plate is provided with a temperature fuse protection component. When the local temperature of the constant temperature heating plate exceeds 150°C due to a fault, the fuse protection component cuts off the heating circuit in that area.

[0018] Furthermore, the electrostatic contact ring of the antistatic module includes an annular body and several elastic fingers. The annular body is made of copper alloy and has an L-shaped cross-section. The horizontal section is fixed to the edge of the device placement area of ​​the device body by bolts, and the vertical section faces the inside of the device placement area. The height of the vertical section is adapted to the thickness of the BGA device packaging substrate. The elastic fingers are evenly distributed along the inner side of the vertical section in the circumferential direction of the annular body. Each elastic finger is made of beryllium copper and has an arc-shaped curved structure. The free end of the elastic finger faces the center of the device placement area, and the free end of the elastic finger is wrapped with a conductive silicone sleeve. The annular body is connected to the antistatic wrist interface through a shielded wire.

[0019] In practical operation scenarios, after the operator wears an anti-static wrist strap and inserts the interface, when the BGA device is placed in the device placement area, the edge of the substrate will contact the conductive silicone sleeve of the elastic contact fingers. The electrostatic charge (such as ±500V electrostatic voltage) generated on the device surface due to friction or induction can be conducted through the contact fingers, the ring body, and the shielding wire to the anti-static wrist strap, and then conducted to the ground by the human body. The entire electrostatic discharge time is ≤100ns, which is far below the electrostatic discharge time threshold that the BGA chip can withstand (usually ≥200ns), effectively preventing electrostatic breakdown of the chip circuit. At the same time, the arc-shaped structure of the elastic contact fingers and the softness of the conductive silicone sleeve can prevent the contact fingers from scratching the edge of the substrate (especially for ceramic materials or thin substrates). Furthermore, the distributed design of several elastic contact fingers ensures that even if there is a slight eccentricity in the placement of the device (eccentricity ≤1mm), a certain number of elastic contact fingers will still be in contact with the substrate, ensuring the reliability of electrostatic conduction and achieving the dual effect of electrostatic protection and substrate protection.

[0020] Furthermore, each clamping unit of the device positioning module includes a fixed base, a horizontal adjustment slide, a vertical adjustment slide, a micro servo motor, and an arc-shaped clamping block. The fixed base is fixed to the main body of the device with screws. The horizontal adjustment slide is slidably connected to the fixed base, with the sliding direction along the radial direction of the device placement area. A rack is provided at the bottom of the slide, and a gear that meshes with the rack is provided on the fixed base. The gear is driven by a first stepper motor. The vertical adjustment slide is slidably connected to the horizontal adjustment slide, with the sliding direction perpendicular to the horizontal adjustment direction. A ball screw is provided on the side of the slide, driven by a second stepper motor. The micro servo motor is fixed to the top of the vertical adjustment slide, and the motor output shaft is connected to the arc-shaped clamping block through a coupling. The arc-shaped surface of the clamping block faces the device placement area, and the arc radius is adapted to the corner radius of the BGA device substrate. The arc surface is covered with a fluororubber buffer layer. A micro pressure sensor is also provided between the clamping block and the micro servo motor. The pressure sensor is electrically connected to the controller and is used to collect the clamping force data of the clamping block on the substrate in real time.

[0021] In actual positioning scenarios, the operator first adjusts the four clamping units to the initial position that matches the size of the BGA device by adjusting the horizontal adjustment slide, and then adjusts the clamping height by adjusting the vertical adjustment slide to align the clamping block with the middle area of ​​the substrate; then the micro servo motor drives the clamping block to move towards the substrate, and when the pressure sensor detects that the clamping force reaches the set threshold, the motor automatically stops, completing the positioning. The advantages of this structure are as follows: First, precise horizontal and vertical adjustments enable centered positioning of the BGA device, ensuring accurate alignment of the metal cover plate and chip gap during subsequent wire stripping. Second, the curved clamping block's fit with the substrate corners prevents clamping force from concentrating on a single point on the substrate (such as right-angle clamping which can easily cause cracking at the substrate corners), thus dispersing clamping stress. Third, the fluororubber buffer layer absorbs minor vibrations during clamping and prevents scratches caused by direct contact between the metal clamping block and the substrate. Fourth, real-time monitoring by the pressure sensor prevents excessive clamping force from deforming the substrate, while also preventing insufficient clamping force from causing device displacement during stripping, achieving a triple effect of precise positioning, substrate protection, and anti-displacement.

[0022] Furthermore, the rotation drive end includes a drive motor, a reduction gearbox, a drive wheel, and a driven wheel, and the tension adjustment unit is a tensioning wheel; the drive motor is a brushless DC motor, the output shaft of which is connected to the input end of the reduction gearbox; the tensioning wheel is located between the drive wheel and the driven wheel, and is connected to the drive end housing through a spring bracket, and can move in a direction perpendicular to the abrasive wire to compensate for the length change of the abrasive wire due to wear or thermal expansion and contraction, and maintain the basic tension of the abrasive wire; the core wire of the resin abrasive wire is high-strength polyethylene fiber, and diamond micro powder is wound on the surface, and the diamond micro powder is fixed by resin adhesive; It also includes a miniature camera, the lens of which is directed toward the contact area between the sand wire and the device, and the contact status is displayed in real time on a display screen on the main body of the device.

[0023] In actual adhesive removal scenarios, once the adhesive layer softens (temperature reaches 80-100℃), the drive motor drives the drive wheel to rotate, and the abrasive wire rubs along the gap at a set speed (usually 500-1500 r / min, adjusted according to the hardness of the adhesive layer). The diamond micropowder can remove the softened adhesive layer. If a hard block of adhesive layer is encountered (such as a localized area of ​​unsoftened sealant), and the camera detects an increase in the vibration amplitude of the abrasive wire, the controller will automatically reduce the speed of the drive motor to prevent the abrasive wire from breaking due to hard friction or damaging the chip due to excessive impact. When the adhesive layer is completely removed (the camera observes a separation gap between the metal cover and the chip ≥ 0.5 mm), the motor automatically stops rotating. The advantages of this structure are as follows: First, the dual-motor linkage and speed reduction transmission ensure stable rotation of the abrasive wire and sufficient torque to adapt to adhesive layers of different hardness; second, the automatic compensation function of the tensioning wheel maintains stable tension of the abrasive wire and avoids discontinuous adhesive removal; third, the real-time monitoring of the miniature camera enables visualization of the adhesive removal process, and combined with the dynamic adjustment of speed and tension, it ensures adhesive removal efficiency while avoiding damage to components, achieving a triple effect of stable adhesive removal, process monitoring, and damage prevention.

[0024] Furthermore, each temperature sensor in the temperature acquisition array is a surface-mount NTC thermistor. Each temperature sensor is connected to the signal input terminal of the controller via a shielded wire. The controller has a built-in temperature control algorithm to filter the temperature data acquired by each sensor.

[0025] The tight fit of the patch sensor ensures accurate temperature measurement and avoids temperature lag caused by air gaps. Secondly, the matrix distribution enables comprehensive temperature acquisition, reflecting the temperature distribution differences on the device surface. Thirdly, the combination of filtering and zoned power adjustment ensures overall temperature stability and solves the problem of uneven local temperature, achieving accurate temperature measurement and uniform heating, providing a stable temperature environment for the softening of the adhesive layer, while avoiding damage to the device from local high temperatures.

[0026] Furthermore, the controller employs segmented control logic and combines it with a temperature diffusion model to achieve dynamic power adjustment for each heating sub-region, including: When the temperature acquisition array collects the average surface temperature of the BGA device Below the target temperature for adhesive layer softening When the temperature reaches 80%, it is determined to be in the low-temperature stage where the adhesive layer has not yet started to soften. The controller controls all heating sub-regions to operate at maximum rated power, while the temperature acquisition array collects the temperature value of the corresponding location in each sub-region at a frequency of 0.5 seconds. A temperature diffusion model is established using the following formula to calculate the temperature diffusion coefficient of each sub-region. : , in, : No. The temperature diffusion coefficient of a heating sub-region reflects the rate at which heat is transferred from that region to the surrounding area; the larger the value, the faster the heat diffuses. : No. A temperature sensor in Real-time temperature data collected continuously; : No. A temperature sensor in Temperature collected at all times; : No. The monitoring area corresponding to each temperature sensor is obtained by dividing the total area of ​​the BGA device packaging substrate by the number of sensors. : The time interval for temperature acquisition in this stage; : No. The distance from the center of each heating sub-region to the center of the adjacent sub-region; when Reaching or exceeding As the adhesive layer begins to soften, the controller, based on the previously established temperature diffusion model, calculates the real-time adjustment power for each heating sub-region using the following formula. : , in: : No. Real-time power adjustment for each heating sub-region; The basic adjustable power is set based on the average heat dissipation rate of the heating sub-region to ensure basic heat supply. : Diffusion coefficient correction factor, obtained through experimental calibration, used to balance the effect of diffusion rate differences on power; : Average temperature diffusivity of all heated sub-regions; Temperature deviation correction factor, obtained through experimental calibration, ensures linear matching between temperature deviation and power regulation; : No. The real-time temperature is collected by a temperature sensor.

[0027] In practical applications, if a certain sub-region heats up quickly, the faster diffusion rate in that region is balanced by slightly reducing the power; if another sub-region heats up slowly, the slower diffusion rate is offset by slightly increasing the power and the temperature overshoot is suppressed, ultimately achieving precise temperature convergence in each region, ensuring uniform softening of the adhesive layer without damaging the solder ball array.

[0028] Furthermore, the controller is based on the temperature diffusivity. By reverse calculation, the total amount of thermal paste and sealant inside the BGA device can be determined. This provides data support for fine-tuning the heating area and power in the near-target stage, including: , in: The total amount of thermal paste and sealant inside BGA devices; The specific heat capacity of the adhesive layer mixture under constant pressure was measured experimentally. : The density of the adhesive layer mixture was measured experimentally; Heating duration during the rapid temperature rise phase at low temperatures; : Thermal conductivity coefficient of the adhesive layer mixture, experimentally measured; The average temperature difference between the constant temperature heating plate and the adhesive layer during the low-temperature stage is calculated as follows: ,in Set the average temperature for the heating plate. Low temperature stage The average value; At the end of the low temperature phase, the first Temperature values ​​collected by a temperature sensor; Ambient temperature of the device; : No. The distance from the center of each heating sub-region to the edge of the adhesive layer; Heating time at low temperatures, and Consistent; : No. The monitoring area corresponding to each temperature sensor; like The controller automatically increases the heating power. Improve; if Setting a minimum value will reduce the heating power and... This reduces the amount of adhesive and achieves closed-loop matching of heating parameters, ensuring that the adhesive layer is completely softened and no excess heat damages the device. Attached Figure Description

[0029] Figure 1 A schematic diagram of an embodiment of an integrated metal cover removal and packaging device for BGA devices; Figure 2A top view of an embodiment of an integrated metal cover removal and packaging device for BGA devices; The markings in the accompanying drawings include: device body 1, anti-static module 2, precision preheating module 3, flexible sanding line adhesive removal module 4, device positioning module 5, and device placement area 11. Detailed Implementation

[0030] The following detailed description illustrates the specific implementation method: BGA device metal cover integrated removal and packaging device (such as...) Figure 1 , Figure 2 As shown, the device includes a main body 1, which integrates an anti-static module 2, a precision preheating module 3, a flexible sanding line adhesive removal module 4, and a device positioning module 5. The antistatic module 2 includes an antistatic wrist interface disposed on the surface of the device body, and an electrostatic contact ring disposed around the device placement area. The electrostatic contact ring and the antistatic wrist interface are respectively grounded. The precision preheating module 3 is located directly below the device placement area 11 and includes a controller, several constant temperature heating plates and several temperature sensors. The temperature sensors form a temperature acquisition array, and the temperature acquisition array and the constant temperature heating plates are electrically connected to the controller. The flexible sanding wire de-adhesive module 4 includes 4 sets of sanding wire assemblies symmetrically arranged around the device placement area. Each set of sanding wire assemblies includes a rotation drive end, a resin sanding wire, and a tension adjustment unit. The resin sanding wire is wound around the rotation drive end and the tension adjustment unit. The rotation drive end is used to drive the resin sanding wire to move along its axial direction. The device positioning module 5 includes four independently adjustable clamping units, which are distributed outside the device placement area 11 and have an elastic buffer layer on the clamping surface.

[0031] Specifically, the electrostatic contact ring of the antistatic module 2 includes an annular body and eight elastic contact fingers. The annular body is made of copper alloy and has an L-shaped cross-section. Its horizontal section is fixed to the edge of the device placement area 11 of the device body 1 by M3 hexagonal bolts. The vertical section faces the inside of the device placement area 11 and the height of the vertical section is set to 1.5mm, which is suitable for BGA device packaging substrates with a thickness of 0.8mm-2.5mm.

[0032] The elastic contacts are evenly distributed along the inner side of the vertical section of the ring body. The included angle between adjacent elastic contacts is 45°. Each elastic contact is made of beryllium copper and has an arc-shaped curved structure with a bending radius of 3mm. The free end of the elastic contact faces the center of the device placement area 11 and is wrapped with a 0.2mm thick conductive silicone sleeve.

[0033] The ring-shaped main body is connected to the anti-static wrist interface on the surface of the main body 1 of the device via a shielded wire. The shielded wire is wrapped with a metal braided mesh shielding layer.

[0034] The precision preheating module 3 is located directly below the device placement area 11 and includes a controller, eight independent constant-temperature heating plates, and eight independent temperature sensors. The eight temperature sensors form a temperature acquisition array. The heating array composed of constant-temperature heating plates is rectangular in shape, with each heating plate corresponding to one of the four sides and the central adhesive layer distribution area under the metal cover of the BGA device. Each heating sub-area has an area of ​​8mm × 8mm, and each constant-temperature heating plate is independently controlled, with a maximum rated power of 50W for a single heating sub-area. The upper surface of the constant-temperature heating plate is covered with a 0.5mm thick polyimide insulating layer, and the edges of the constant-temperature heating plates are equipped with temperature-controlled fuse protection devices. When the local temperature of the constant-temperature heating plate exceeds 150℃ due to a fault, the fuse protection devices automatically cut off the heating circuit in that area.

[0035] Each temperature sensor in the temperature acquisition array is a surface-mount NTC thermistor (model NTC-MF52-10K), with a package size of 2mm × 2mm × 0.5mm. The temperature measurement range is -50℃ to 200℃, the measurement accuracy is ±0.5℃, and the response time is ≤1s. The eight sensors are arranged in a matrix, with one in the center and seven around the perimeter. The distance between each sensor and the edge of the device is one-quarter of the device's side length. Each temperature sensor is connected to the controller's signal input terminal via shielded wires. All wires are 500mm ± 5mm long and have consistent resistance (error ≤1%). The controller uses an industrial-grade PLC (model S7-200SMART) with a built-in temperature control algorithm. It performs a moving average filtering process on the temperature data collected by each sensor (filtering window is 5 samples).

[0036] Each clamping unit of the device positioning module 5 includes a fixed base, a horizontal adjustment slide, a vertical adjustment slide, a micro servo motor, and an arc-shaped clamping block. The fixed base is fixed to the main body 1 of the device by M4 screws. The horizontal adjustment slide is slidably connected to the fixed base, and the sliding direction is along the radial direction of the device placement area 11. The bottom of the slide is provided with a rack with a module of 0.5. The fixed base is provided with a gear that meshes with the rack. The gear is driven by a first stepper motor of model 42HS03. The adjustment accuracy can reach 0.01mm, and the adjustment range is 0-50mm.

[0037] The longitudinal adjustment slide and the transverse adjustment slide are slidably connected, with the sliding direction perpendicular to the transverse adjustment direction. A ball screw 531 with a lead of 2mm is located on the side of the slide, driven by a second stepper motor (model 42HS03), with an adjustment range of 0-5mm. A micro servo motor (model MG996R) is fixed to the top of the longitudinal adjustment slide. The motor output shaft is connected to the arc-shaped clamping block 55 via a coupling. The arc-shaped surface of the clamping block 55 faces the device placement area 11, with an arc radius of 2mm to accommodate the corner radii of common BGA device substrates. The arc-shaped surface is covered with a 0.3mm thick fluororubber buffer layer 551, with a Shore hardness of 40HA. Between the clamping block 55 and the micro servo motor, a micro pressure sensor (model FSH0604N) with a range of 0-50N and an accuracy of 0.1N is installed. The pressure sensor is electrically connected to the controller to collect real-time clamping force data of the clamping block 55 on the substrate.

[0038] The flexible sanding line adhesive removal module 4's rotation drive end includes a drive motor, a reduction gearbox, a driving wheel, and a driven wheel. The tension adjustment unit is a tensioning wheel. The drive motor is a brushless DC motor (model BLDC-3650) with a rated speed of 0-3000 r / min and a speed adjustment accuracy of 1 r / min. The motor output shaft is connected to the input end of the reduction gearbox, which has a reduction ratio of 1:10, converting the high speed of the motor into low speed and high torque of the driving wheel. Both the driving wheel and the driven wheel are made of stainless steel, with a diameter of 20 mm. The wheel groove cross-section is V-shaped (with an included angle of 60°), and the wheel groove surface has 0.1 mm deep anti-slip textures.

[0039] The tensioning wheel is located between the driving and driven wheels and is connected to the drive end housing via a spring bracket. It can move in a direction perpendicular to the abrasive wire, with a compensation range of 0-5mm. It is used to compensate for length changes in the abrasive wire caused by wear or thermal expansion and contraction, maintaining the basic tension of the abrasive wire. The core wire of the resin abrasive wire 47 is made of high-strength polyethylene fiber (tensile strength ≥50N), and the surface is wrapped with diamond micro-powder with a particle size of 5-10μm. The diamond micro-powder is fixed by resin adhesive. The abrasive wire diameter is 0.5mm, with a diameter tolerance of ±0.05mm.

[0040] The flexible sanding line adhesive removal module 4 also includes a miniature camera 48 (1280×720 resolution, 30fps frame rate), with the camera lens facing the contact area between the sanding line and the device, and the contact status is displayed in real time on the display screen 49 on the main body of the device 1.

[0041] In use, the operator first puts on an anti-static wrist strap and inserts it into the anti-static wrist strap interface. The BGA device to be removed (20mm × 20mm in size, 1.2mm thick package substrate) is placed in the device placement area 11. The clamping force threshold is set to 6N via the controller, and the device positioning module 5 is activated: the first stepper motor drives the gear to rotate, moving the lateral adjustment slide to adjust the four clamping units to their initial positions matching the BGA device size; the second stepper motor drives the ball screw 531 to rotate, moving the longitudinal adjustment slide to adjust the clamping block 55 to the height aligned with the center area of ​​the substrate (1.5mm from the bottom of the substrate); a micro servo motor drives the arc-shaped clamping block to move towards the substrate. When the pressure sensor detects that the clamping force reaches 6N, the motor automatically stops, completing the precise positioning of the BGA device.

[0042] At this time, the edge of the BGA device substrate is in close contact with the conductive silicone sleeve of the elastic finger, forming an electrostatic conduction path. The electrostatic charge generated on the device surface due to friction during placement is conducted to the ground through the elastic finger, the ring body, and the shielding wire. The electrostatic discharge time is 80ns, ensuring that the chip is not damaged by electrostatic discharge.

[0043] The operator sets the target softening temperature of the adhesive layer, T_set, to 90℃ via the controller and starts the precision preheating module 3. The controller uses segmented control logic. During the rapid heating phase at low temperatures (T_avg < 0.8 × T_set): The temperature acquisition array collects the temperature value T_i at the corresponding location of each heating sub-region at a frequency of 0.5 s / time. The controller calculates the average surface temperature T_avg of the BGA device. In the initial stage, T_avg = ℃ (ambient temperature), which is below 0.8 × 90℃ = 72℃, and is therefore determined to be in the low-temperature phase. The controller controls all heating sub-regions to operate at the maximum rated power of 50W. Simultaneously, a temperature diffusion model is established using the following formula to calculate the temperature diffusion coefficient of each sub-region. : ,

[0044] in, : No. The temperature diffusion coefficient of a heating sub-region reflects the rate at which heat is transferred from that region to the surrounding area; the larger the value, the faster the heat diffuses. : No. A temperature sensor in Real-time temperature data collected continuously; : No. A temperature sensor in Temperature collected at all times; : No. The monitoring area corresponding to each temperature sensor is obtained by dividing the total area of ​​the BGA device packaging substrate by the number of sensors. : The time interval for temperature acquisition in this stage; : No. The distance from the center of each heating sub-region to the center of the adjacent sub-region; This value can be used to determine the rate of heat diffusion in the area.

[0045] Near-target precise temperature control stage (T_avg≥0.8×T_set): After heating for 120 seconds, T_avg=72℃, reaching 0.8×T_set, which is determined to be the near-target stage, and the adhesive layer begins to gradually soften. The controller is based on the previously calculated temperature diffusion coefficient. The real-time adjustable power for each heating sub-region is calculated using the following formula. : ,

[0046] in: : No. Real-time power adjustment for each heating sub-region; The basic adjustable power is set based on the average heat dissipation rate of the heating sub-region to ensure basic heat supply. : Diffusion coefficient correction factor, obtained through experimental calibration, used to balance the effect of diffusion rate differences on power; : Average temperature diffusivity of all heated sub-regions; Temperature deviation correction factor, obtained through experimental calibration, ensures linear matching between temperature deviation and power regulation; : No. The real-time temperature is collected by a temperature sensor.

[0047] Temperature overshoot is suppressed by slightly adjusting the power.

[0048] Meanwhile, the controller is based on the temperature diffusivity. By reverse calculation, the total amount of thermal paste and sealant inside the BGA device can be determined. : ,

[0049] in: The total amount of thermal paste and sealant inside BGA devices; The specific heat capacity of the adhesive layer mixture under constant pressure was measured experimentally. : The density of the adhesive layer mixture was measured experimentally; Heating duration during the rapid temperature rise phase at low temperatures; : Thermal conductivity coefficient of the adhesive layer mixture, experimentally measured; The average temperature difference between the constant temperature heating plate and the adhesive layer during the low-temperature stage is calculated as follows: ,in Set the average temperature for the heating plate. Low temperature stage The average value; At the end of the low temperature phase, the first Temperature values ​​collected by a temperature sensor; Ambient temperature of the device; : No. The distance from the center of each heating sub-region to the edge of the adhesive layer; Heating time at low temperatures, and Consistent; : No. The monitoring area corresponding to each temperature sensor; like The controller automatically increases the heating power. Improve; if Setting a minimum value will reduce the heating power and... This reduces the amount of adhesive and achieves closed-loop adaptation of heating parameters, ensuring that the adhesive layer is completely softened and no excess heat damages the device.

[0050] When the adhesive layer temperature stabilizes at 85-90℃ (the adhesive layer softens), the flexible abrasive wire de-adhesive module 4 is activated, and the abrasive wire speed is set to v=1000r / min. The drive motor drives the active wheel to rotate, which in turn drives the driven wheel to rotate synchronously through the resin abrasive wire 47. The abrasive wire moves at a constant speed along the gap between the metal cover plate and the chip, and the diamond micropowder removes the softened adhesive layer. The tensioning wheel automatically compensates for the length changes of the abrasive wire caused by thermal expansion and contraction through a spring bracket, maintaining the basic tension of the abrasive wire.

[0051] The miniature camera 48 captures real-time images of the contact status between the sanding wire and the device and transmits the data to the display screen 49, allowing operators to visually observe the adhesive removal progress. If the camera detects a sanding wire vibration amplitude ≥0.1mm (encountering a hard block of adhesive), the controller reduces the sanding wire speed to prevent the sanding wire from breaking or excessive impact damaging the chip. When the camera observes a separation gap ≥0.5mm between the metal cover and the chip, the controller stops the drive motor, completing the adhesive removal process.

[0052] Then, the precision preheating module 3 is turned off. After the device cools to room temperature, the controller controls the micro servo motor to rotate in the opposite direction, driving the arc-shaped clamping block away from the BGA device. The operator can then remove the BGA device after the metal cover has been removed. The chip, packaging substrate and solder ball array remain intact and can be directly used for subsequent repair or repackaging.

[0053] The above are merely embodiments of the present invention. The invention is not limited to the fields covered by these embodiments. Commonly known structures and characteristics in the solutions are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are able to access all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A BGA device metal cover plate integrated dismounting packaging device, comprising a device main body, characterized in that, The device body is integrally provided with an anti-static module, a precise preheating module, a flexible sand line degumming module and a device positioning module; The anti-static module comprises an anti-static wrist interface arranged on the surface of the device body and an electrostatic contact ring arranged around the device placement area, and the anti-static wrist interface and the electrostatic contact ring are respectively grounded. The precise preheating module is located directly below the device placement area and comprises a controller, a plurality of constant temperature heating plates and a plurality of temperature sensors, the plurality of temperature sensors form a temperature collection array, and the temperature collection array and the constant temperature heating plates are electrically connected with the controller respectively. The flexible sand line degumming module comprises four groups of sand line assemblies symmetrically arranged around the device placement area, each group of sand line assembly comprises a rotating driving end, a resin sand line and a tension adjusting unit, the resin sand line is wound around the rotating driving end and the tension adjusting unit, and the rotating driving end is used for driving the resin sand line to move along the axial direction thereof. The device positioning module comprises four independently adjustable clamping units, the clamping units are distributed outside the device placement area, and the clamping surface is provided with an elastic buffer layer.

2. The BGA device metal lid integrated pick-and-place packaging apparatus of claim 1, wherein, The constant temperature heating plate is 5, corresponding to the four edges and the center glue layer distribution area below the BGA device metal cover plate respectively, and each constant temperature heating plate independently heats one heating sub-area.

3. The BGA device metal lid integrated lift-off package of claim 2, wherein, The upper surface of the constant temperature heating plate is covered with a layer of polyimide insulating layer, and the edge of the constant temperature heating plate is provided with a temperature fuse protection piece, when the local temperature of the constant temperature heating plate exceeds 150 DEG C due to failure, the fuse protection piece cuts off the heating circuit of the area.

4. The BGA device metal lid integrated pick-and-place packaging apparatus of claim 3, wherein, The electrostatic contact ring of the anti-static module comprises a ring body and a plurality of elastic fingers, the ring body is made of copper alloy, the cross section is L-shaped, the horizontal section is fixed on the edge of the device placement area of the device body through bolts, the vertical section faces the inside of the device placement area, and the height of the vertical section is matched with the thickness of the BGA device packaging substrate, the elastic fingers are uniformly distributed along the inside of the vertical section of the ring body, each elastic finger is made of beryllium copper and has an arc-shaped curved structure, the free end of the elastic finger faces the center of the device placement area, and the free end of the elastic finger is wrapped with a conductive silicone sleeve, and the ring body is connected with the anti-static wrist interface through a shielding wire.

5. The BGA device metal lid integrated de-lidding packaging apparatus of claim 4, wherein, Each clamping unit of the device positioning module comprises a fixed seat, a transverse adjusting sliding table, a longitudinal adjusting sliding table, a micro servo motor and an arc-shaped clamping block, the fixed seat is fixed on the device body by screws, the transverse adjusting sliding table is slidingly connected with the fixed seat, the sliding direction is along the radial direction of the device placement area, the bottom of the sliding table is provided with a rack, and the fixed seat is provided with a gear meshing with the rack, and the gear is driven by a first stepper motor.

6. The BGA device metal lid integrated de-lidding packaging apparatus of claim 5, wherein, The longitudinal adjustment sliding table and the transverse adjustment sliding table are slidingly connected, the sliding direction is perpendicular to the transverse adjustment direction, the side surface of the sliding table is provided with a ball screw driven by a second stepping motor; a micro servo motor is fixed on the top of the longitudinal adjustment sliding table, the motor output shaft is connected with an arc-shaped clamping block through a shaft coupling, the arc-shaped surface of the clamping block faces the device placement area, the arc radius is adapted to the corner radius of the BGA device substrate, and the arc-shaped surface is covered with a fluororubber buffer layer; a micro pressure sensor is further arranged between the clamping block and the micro servo motor, the pressure sensor is electrically connected with the controller, and is used for collecting the clamping force data of the clamping block on the substrate in real time.

7. The BGA device metal lid integrated lift-off package of claim 6, wherein, The rotating driving end comprises a driving motor, a speed reducer, a driving wheel and a driven wheel, and the tension adjusting unit is a tensioning wheel; the driving motor is a brushless DC motor, the output shaft of the brushless DC motor is connected with the input end of the speed reducer, the tensioning wheel is located between the driving wheel and the driven wheel, is connected with the driving end shell through a spring support, can move in a direction perpendicular to the sand line, compensates the length change of the sand line caused by abrasion or thermal expansion and cold shrinkage, and maintains the basic tension of the sand line; the core wire of the resin sand line is high-strength polyethylene fiber, the surface is wound with diamond micro powder, and the diamond micro powder is fixed through a resin adhesive; The micro camera is also included, the lens of the micro camera faces the contact area of the sand line and the device, and the contact state is displayed in real time through the display screen on the device body.

8. The BGA device metal lid integrated pick-and-place packaging apparatus of claim 7, wherein, Each temperature sensor of the temperature acquisition array adopts a patch type NTC thermistor, each temperature sensor is connected with the signal input end of the controller through a shielding wire, and the controller is provided with a temperature control algorithm to filter the temperature data collected by each sensor.

9. The BGA device metal lid integrated de-lidding packaging apparatus of claim 8, wherein, The controller adopts a segmented control logic, and realizes dynamic adjustment of the power of each heating sub-region in combination with a temperature diffusion model, including: When the temperature acquisition array acquires the average temperature of the BGA device surface Lower than the softening target temperature of the adhesive layer When the temperature is lower than 80% of the softening target temperature of the adhesive layer, it is determined that the adhesive layer is in a low-temperature stage without softening, and the controller controls all heating sub-regions to operate at maximum rated power, while the temperature acquisition array acquires temperature values at a frequency of 0.5s / time at corresponding positions of each sub-region , and a temperature diffusion model is established by the following formula to calculate the temperature diffusion coefficient of each sub-region : ， Wherein, : No. The temperature diffusion coefficient of a heating sub-region reflects the rate at which heat is transferred from that region to the surrounding area; the larger the value, the faster the heat diffuses. : the first temperature sensor collects the real-time temperature at the time moment ​​ : the temperature sensed by the first temperature sensor at the time instant t1 t1​ : the first temperature sensor corresponds to a monitoring area of 1 / 4 of the total area of the BGA device package substrate; and the second temperature sensor corresponds to a monitoring area of 1 / 4 of the total area of the BGA device package substrate. : Temperature acquisition time interval for this phase; : No. The distance from the center of each heating sub-region to the center of the adjacent sub-region; when Reaching or exceeding As the adhesive layer begins to soften, the controller, based on the previously established temperature diffusion model, calculates the real-time adjustment power for each heating sub-region using the following formula. : ， Wherein: : No. Real-time power adjustment for each heating sub-region; : basic regulation power, based on the average heat dissipation rate of the heating sub-area, to ensure basic heat supply; : Diffusion coefficient correction factor, experimentally calibrated to balance the effect of diffusion rate differences on power; : average temperature diffusivity of all heating sub-areas; : temperature deviation correction factor, experimentally calibrated to ensure linear matching of temperature deviation and power adjustment; : the first temperature sensor collects real-time temperature. : the second temperature sensor collects real-time temperature.

10. The BGA device metal lid integrated de-lidding packaging apparatus of claim 9, wherein, The controller is based on the temperature diffusion coefficient , back-propagation of the total amount of glue of the heat dissipation glue and the sealing glue in the BGA device , provide data support for the fine tuning of the heating area and power in the near target stage, including: ， Wherein: : total amount of thermal paste and sealant in the BGA device : Adhesive layer mixed constant pressure specific heat capacity, experimentally measured; : experimental; and : experimental; and : experimental; and : heating duration of the low-temperature rapid heating stage; : Thermal conductivity of the glue layer, measured experimentally; : the average temperature difference between the low-temperature stage constant temperature hot plate and the adhesive layer, calculated in the following manner , wherein is the average set temperature of the hot plate, is the average value of the low-temperature stage . : temperature value collected by the temperature sensor at the end of the low temperature phase : temperature value collected by the temperature sensor at the end of the low temperature phase : device ambient temperature; : No. The distance from the center of each heating sub-region to the edge of the adhesive layer; : the heating duration in the low-temperature stage is consistent with the same. : the first temperature sensor corresponds to a first monitoring area; and the second temperature sensor corresponds to a second monitoring area. If , the controller automatically increases the heating power, and increases; if the preset minimum value, the heating power is reduced, and is reduced, realizing closed-loop adaptation of the glue amount and heating parameters, ensuring that the glue layer is completely softened and the device is not damaged by excessive heat.

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