High-precision multi-layer laminated and aligned PCB (Printed Circuit Board) printing process

Abstract

The invention relates to the field of PCB (printed circuit board) printing, in particular to a high-precision multi-layer lamination and alignment PCB printing process which comprises a substrate pretreatment stage, a substrate preassembly stage, a dynamic lamination stage and a finished product output stage, the dynamic lamination stage comprises preheating treatment and resonance impurity removal treatment, and the lamination stage is divided into multi-stage lamination. And air bubbles and resin between the laminated bodies are optimized in the second pressing stage. According to the method, the inner-layer core plate and the copper foil are pretreated, so that positioning of the multi-layer core plate is more accurate and detection is facilitated, meanwhile, nanoscale micropores are formed in the copper foil through a laser technology to improve the flowing property of subsequent resin, and in the pressing process, pre-pressing and multi-stage pressing are set to improve the pressing accuracy; and in the second-stage pressing process, the dispersion direction of internal bubbles and the flowing direction of resin are improved through an ultrasonic device, a radiation heating device, a magnetic field assisting device and the like, the alignment accuracy and the pressing precision of the plate are further improved, and the machining efficiency is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB printing, and in particular to a high-precision multi-layer lamination and alignment PCB printing process. Background Art

[0002] PCB lamination is a crucial step in the PCB manufacturing process. It involves heating and pressurizing multi-layer PCB sheets to compress the insulating medium between the layers, thereby achieving connection between the circuit layers.

[0003] In the existing technology, some pressing devices are implemented through a single mechanical pressure spring or hydraulic or pneumatic equipment, which is difficult to cope with the pressing process of multi-layer PCB boards, resulting in poor material thickness fluctuation and high requirements for board alignment. At the same time, the alignment system of the traditional pressing device still uses manual cooperation with the visual system, and is unable to detect the board plane system in real time, resulting in the alignment accuracy decreasing with the pressing time and number of layers. Therefore, there is an urgent need to propose a high-precision multi-layer lamination and alignment PCB printing process. Summary of the Invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a high-precision multi-layer lamination and alignment PCB printing process.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The high-precision multi-layer lamination and alignment PCB printing process includes the following steps:

[0007] S1, substrate pretreatment;

[0008] A. Select the corresponding copper foil, prepreg, and inner core board, and place the inner core board into a plasma-enhanced atomic layer deposition machine to generate a 2nm positioning point array on the board surface. Then, freeze the board to achieve a -50℃ locking point array positioning benchmark.

[0009] B. After the panel is positioned by the point array, the corresponding reference mark is scanned by the machine vision system to establish the corresponding plane coordinate system;

[0010] S2, substrate pre-assembly;

[0011] A. Place the corresponding panels into the inspection chamber using a robotic arm. The laser quantum head emits corresponding quantum pairs to the stacked panels. The AI vision module performs vertical inspection of the panels, and the different heat maps formed by different panels are used to generate the plane position difference.

[0012] B. Use the micro-motion table to adjust the position of each inner core plate to align them;

[0013] C. After the initial alignment, the servo hydraulic cylinder is used to lock the layers with a preload of 15kN to avoid misalignment between the laminated bodies;

[0014] S3, dynamic pressing stage;

[0015] A. Preheating treatment: Specifically, the laminate is placed in a graphene heating film for temperature control. Starting from the center of the layer, the temperature is radiated outward in 10°C increments, forming three temperature difference zones on the board surface.

[0016] B. Resonance impurity removal treatment, specifically, emitting 50MHz ultrasonic waves to the preheated plate to drive out bubbles in the pre-pressed laminate;

[0017] C. During the pressing stage, the array distributed pressure head is controlled to descend to a safe height, and the surface of the laminate is scanned twice by a grating displacement sensor to ensure the error between each layer of the plate. The pressure head is controlled to heat up to the specified heating process temperature and is in pressure contact with the laminate;

[0018] S4, finished product output stage;

[0019] A. Use pulse water cooling to cool the finished plate to reduce its residual stress;

[0020] B. Then put the cooled laminate into a 3D laser scanner for inspection to identify the warping of the laminate. When the edge warping is higher than 0.3%, it is considered scrapped.

[0021] Preferably, the copper foil is preheated on a preheating table before processing, and the preheating temperature is 30° C. lower than the formal pressing temperature.

[0022] Preferably, in the preheating treatment stage S3, the temperature of the center area of the laminate is 190° C. to ensure the strength of the plate, and the temperature of the edge area of the laminate is 200° C. to ensure edge fixation.

[0023] Preferably, the array of distributed pressure heads includes pressure heads, each group of which is provided with a double-acting servo hydraulic cylinder, and each pressure head is equipped with a magnetorheological damper parallel mechanism.

[0024] Preferably, the pressing safety height is 2 mm from the upper surface of the laminate.

[0025] Preferably, the pressing stage of S3 is divided into multi-stage pressing. In the first stage, the pressure head is maintained at 3Mpa for 15s to ensure that the air in the plate is completely discharged. After the end, the pressure of the pressure head is increased and rises to the specified processing pressure. The pressure increase rate is 0.3Mpa / s. This is the second stage. After the end, the pressure is reduced to 80Mpa and left to stand for 90s to complete the pressing.

[0026] Preferably, before the laminate is sent into the lamination chamber, a resonance device is used to vibrate the resin molecules in the prepreg inside the laminate so as to align them in a directional manner.

[0027] Preferably, in the second pressing stage, the pressing head generates a dynamic magnetic field through the superconducting coil, thereby increasing the filling rate of the resin in the gaps between the plate layers, and the pressing head has a built-in pressure pad ceramic array, which emits shear waves during the pressing process to directionally soften the resin and reduce flow resistance.

[0028] Preferably, during the substrate pretreatment stage, a liquid metal composite film is inserted and laid between each semi-cured sheet, and during the second pressing stage of S3, the composite film is heated to liquefy to form a nano-scale slip layer, allowing each layer to produce a compensatory displacement of less than 10 microns under pressure, and during the finished product output stage, it is instantaneously solidified after cooling, locking the layer position inside the finished board body, so as to effectively reduce warping.

[0029] The beneficial effects of the present invention are:

[0030] In the present invention, the inner core board and copper foil are pre-treated to make the positioning of the multi-layer core board more accurate and easier to detect. At the same time, nano-scale micropores are formed in the copper foil through laser technology to improve the subsequent resin flow performance. In the pressing process, pre-pressing and multi-stage pressing are set to improve the pressing accuracy. In the secondary pressing, ultrasonic waves, radiation heating, magnetic field assistance and other devices are used to improve the internal bubble dispersion and the flow direction of the resin, further improving the alignment accuracy and pressing accuracy of the board parts and ensuring processing efficiency. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0032] The high-precision multi-layer lamination and alignment PCB printing process includes the following steps:

[0033] S1, substrate pretreatment;

[0034] A. Select the corresponding copper foil, prepreg, and inner core board, and place the inner core board into a plasma-enhanced atomic layer deposition machine to generate a 2nm positioning point array on the board surface. Then, freeze the board to achieve a -50℃ locking point array positioning benchmark.

[0035] B. After the panel is positioned by the point array, the corresponding reference mark is scanned by the machine vision system to establish the corresponding plane coordinate system;

[0036] S2, substrate pre-assembly;

[0037] A. Place the corresponding panels into the inspection chamber using a robotic arm. The laser quantum head emits corresponding quantum pairs to the stacked panels. The AI vision module performs vertical inspection of the panels, and the different heat maps formed by different panels are used to generate the plane position difference.

[0038] B. Use the micro-motion table to adjust the position of each inner core plate to align them;

[0039] C. After the initial alignment, the servo hydraulic cylinder is used to lock the layers with a preload of 15kN to avoid misalignment between the laminated bodies;

[0040] S3, dynamic pressing stage;

[0041] A. Preheating treatment: Specifically, the laminate is placed in a graphene heating film for temperature control. Starting from the center of the layer, the temperature is radiated outward in 10°C increments, forming three temperature difference zones on the board surface.

[0042] B. Resonance impurity removal treatment, specifically, emitting 50MHz ultrasonic waves to the preheated plate to drive out bubbles in the pre-pressed laminate;

[0043] C. During the pressing stage, the array distributed pressure head is controlled to descend to a safe height, and the surface of the laminate is scanned twice by a grating displacement sensor to ensure the error between each layer of the plate. The pressure head is controlled to heat up to the specified heating process temperature and is in pressure contact with the laminate;

[0044] S4, finished product output stage;

[0045] A. Use pulse water cooling to cool the finished plate to reduce its residual stress;

[0046] B. Then put the cooled laminate into a 3D laser scanner for inspection to identify the warping of the laminate. When the edge warping is higher than 0.3%, it is considered scrapped.

[0047] Furthermore, before processing, the copper foil is preheated on a preheating table, and its preheating temperature is 30°C lower than the formal pressing temperature. Specifically, the copper foil is placed in a laser cabin and placed on a translation table, and then the surface of the copper foil is burned by a corresponding light beam to form a porous nanostructure on its surface, so that the subsequent resin can enter the nanopores on the copper foil surface.

[0048] Furthermore, in the preheating treatment stage S3, the temperature of the center area of the laminate is 190° C. to ensure the strength of the panel, and the temperature of the edge area of the laminate is 200° C. to ensure edge fixation.

[0049] Furthermore, the array of distributed pressure heads includes pressure heads, each group of which is provided with a double-acting servo hydraulic cylinder, and each pressure head is equipped with a magnetorheological damper parallel mechanism.

[0050] Furthermore, the pressing safety height is 2 mm from the upper surface of the laminate.

[0051] Furthermore, the pressing stage of S3 is divided into multiple stages. In the first stage, the pressure head is maintained at 3 MPa for 15 seconds to ensure that the air in the plate is completely exhausted. After the end, the pressure of the pressure head is increased and rises to the specified processing pressure. The pressure increase rate is 0.3 MPa / s. This is the second stage. After the end, the pressure is reduced to 80 MPa and left to stand for 90 seconds to complete the pressing.

[0052] Furthermore, before the laminate is sent into the lamination chamber, a resonance device is used to vibrate the resin molecules in the prepreg inside the laminate to achieve directional alignment.

[0053] Furthermore, in the second pressing stage, the pressing head generates a dynamic magnetic field through the superconducting coil, thereby increasing the filling rate of the resin in the gaps between the plate layers. The pressing head also has a built-in pressure pad ceramic array, which emits shear waves during the pressing process to directionally soften the resin and reduce flow resistance.

[0054] Furthermore, during the substrate pretreatment stage, a liquid metal composite film is inserted and laid between each semi-cured sheet, and during the second pressing stage of S3, the composite film is heated to liquefy and form a nano-scale slip layer, allowing each layer to produce a compensatory displacement of less than 10 microns under pressure, and during the finished product output stage, it is instantaneously solidified after cooling, locking the layer position inside the finished board body to effectively reduce warping.

[0055] In this embodiment, before the lamination process, the copper foil, semi-cured sheet, and inner core board are pretreated, wherein the inner core board is placed in a plasma enhanced atomic layer deposition machine to generate a 2nm positioning point array on the surface of the board, and then the board is frozen to achieve a -50°C locking point array positioning reference for subsequent positioning. The board after point array positioning is then taken and the corresponding reference mark is scanned by a mechanical vision system to establish a corresponding plane coordinate system.

[0056] The corresponding panels are then placed into the inspection chamber by a robotic arm. The order is to cover the copper foil with prepreg, place the inner core board, and then repeat the stacking of the prepreg. The laser quantum head then emits the corresponding quantum pairs to the stacked panels. The AI vision module then performs vertical inspection of the panels. The different heat maps formed by different panels are used to form the plane position difference. At this time, the reference marks made during preprocessing are compared to achieve accurate comparison.

[0057] If the corresponding inner core plate has a certain deviation, the micro-motion table will adjust the position of each inner core plate to align them to ensure the accuracy of the pressing.

[0058] After the initial alignment, the panels are preliminarily pressed together with a preload of 15kN by a servo hydraulic cylinder, thereby locking the layers and preventing misalignment between the laminated bodies.

[0059] Then, the laminated body after preliminary pressing is preheated:

[0060] The laminate is placed in a graphene heating film for temperature control treatment. The temperature in the center area of the laminate is 190°C to ensure the strength of the panel, and the temperature in the edge area of the laminate is 200°C to ensure edge fixation. The transition area is controlled at 180°C to ensure the transition effect.

[0061] Then, in order to ensure that the bubbles in the laminate are eliminated, a resonance impurity removal treatment is performed on it, 50MHz ultrasonic waves are emitted to the pre-heated plate, and the bubbles in the pre-pressed laminate are driven out and discharged.

[0062] The array distributed pressure head is controlled to descend to a safe height, specifically 2 mm from the upper surface of the laminate, and the surface of the laminate is scanned again using a nano-grating displacement sensor to calibrate the reference positioning during pre-processing to ensure the error between each layer of panels.

[0063] During this process, the pressing of the press head is divided into multiple stages. In the first stage, the press head is kept at 3Mpa for 15 seconds to ensure that the air in the plate is completely exhausted. After that, the press head pressure is increased and raised to the specified processing pressure at a pressure increase rate of 0.3Mpa / s. This is the second stage. After that, the pressure is reduced to 80Mpa and left to stand for 90 seconds to complete the pressing.

[0064] The pressing head generates a dynamic magnetic field through a superconducting coil, thereby increasing the filling rate of the resin in the gaps between the plate layers. The pressing head also has a built-in pressure pad ceramic array, which emits shear waves during the pressing process to directionally soften the resin and reduce flow resistance.

[0065] The pressure head is then heated to the specified heating process temperature and brought into pressure contact with the laminate to obtain a finished panel. The finished panel is then cooled by pulsed water cooling to reduce residual stress. The cooled laminate is then placed in a three-dimensional laser scanner for inspection to identify the warpage of the panel. When the edge warping is higher than 0.3%, it is deemed scrapped.

[0066] In actual application, the copper foil is preheated on a preheating table before processing. The preheating temperature is 30°C lower than the formal pressing temperature. Specifically, the copper foil is placed in a laser cabin and placed on a translation table. The corresponding light beam is then used to burn the surface of the copper foil, forming a porous nanostructure on its surface so that subsequent resin can enter the nanopores on the surface of the copper foil.

[0067] In actual application, during the substrate pretreatment stage, a liquid metal composite film is inserted and laid between each semi-cured sheet. During the second pressing stage of S3, the composite film is heated to liquefy and form a nano-scale slip layer, allowing each layer to produce a compensatory displacement of less than 10 microns under pressure. During the finished product output stage, it is instantaneously solidified after cooling, locking the layer position inside the finished board body to effectively reduce warping.

[0068] This device performs multiple pre-treatments on the panels to achieve precise positioning. In the actual lamination process, multi-stage lamination is used, and ultrasonic and magnetic field-assisted processes are used to effectively reduce the gap between the panels and the lamination void rate.

[0069] By pre-treating the inner core board and copper foil, the positioning of the multi-layer core board is made more accurate and easier to detect. At the same time, nano-scale micropores are formed in the copper foil through laser technology to improve the subsequent resin flow performance. In the pressing process, pre-pressing and multi-stage pressing are set to improve the pressing accuracy. In the second-stage pressing, ultrasonic waves, radiation heating, magnetic field assistance and other devices are used to improve the internal bubble dispersion and the flow direction of the resin, further improving the alignment accuracy and pressing accuracy of the panels and ensuring processing efficiency.

[0070] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. High-precision multi-layer lamination and alignment PCB printing process, characterized by: The following steps are involved: S1, substrate pretreatment; A. Select the corresponding copper foil, prepreg, and inner core board, and place the inner core board into a plasma-enhanced atomic layer deposition machine to generate a 2nm positioning point array on the board surface. Then, freeze the board to achieve a -50℃ locking point array positioning benchmark. B. After the panel is positioned by the point array, the corresponding reference mark is scanned by the machine vision system to establish the corresponding plane coordinate system; S2, substrate pre-assembly; A. Place the corresponding panels into the inspection chamber using a robotic arm. The laser quantum head emits corresponding quantum pairs to the stacked panels. The AI vision module performs vertical inspection of the panels, and the different heat maps formed by different panels are used to generate the plane position difference. B. Use the micro-motion table to adjust the position of each inner core plate to align them; C. After the initial alignment, the servo hydraulic cylinder is used to lock the layers with a preload of 15kN to avoid misalignment between the laminated bodies; S3, dynamic pressing stage; A. Preheating treatment: Specifically, the laminate is placed in a graphene heating film for temperature control. Starting from the center of the layer, the temperature is radiated outward in 10°C increments, forming three temperature difference zones on the board surface. B. Resonance impurity removal treatment, specifically, emitting 50MHz ultrasonic waves to the preheated plate to drive out bubbles in the pre-pressed laminate; C. During the pressing stage, the array distributed pressure head is controlled to descend to a safe height, and the surface of the laminate is scanned twice by a grating displacement sensor to ensure the error between each layer of the plate. The pressure head is controlled to heat up to the specified heating process temperature and is in pressure contact with the laminate; S4, finished product output stage; A. Use pulse water cooling to cool the finished plate to reduce its residual stress; B. Then put the cooled laminate into a 3D laser scanner for inspection to identify the warping of the laminate. When the edge warping is higher than 0.3%, it is considered scrapped.

2. The high-precision multi-layer lamination and alignment PCB printing process according to claim 1, characterized in that: Before processing, the copper foil is preheated on a preheating table, and the preheating temperature is 30° C. lower than the formal pressing temperature.

3. The high-precision multi-layer lamination and alignment PCB printing process according to claim 1, characterized in that: In the preheating treatment stage S3, the temperature of the center area of the laminate is 190° C. to ensure the strength of the plate, and the temperature of the edge area of the laminate is 200° C. to ensure edge fixation.

4. The high-precision multi-layer lamination and alignment PCB printing process according to claim 1, characterized in that: The array of distributed pressure heads includes pressure heads, each group of which is provided with a double-acting servo hydraulic cylinder, and each pressure head is equipped with a magnetorheological damper parallel mechanism.

5. The high-precision multi-layer lamination and alignment PCB printing process according to claim 1, characterized in that: The pressing safety height is 2 mm from the upper surface of the laminate.

6. The high-precision multi-layer lamination and alignment PCB printing process according to claim 1, characterized in that: The pressing stage of S3 is divided into multiple stages. In the first stage, the pressure head is maintained at 3 MPa for 15 seconds to ensure that the air in the plate is completely exhausted. After the pressure is completed, the pressure of the pressure head is increased and rises to the specified processing pressure. The pressure increase rate is 0.3 MPa / s. This is the second stage. After the pressure is completed, the pressure is reduced to 80 MPa and left to stand for 90 seconds to complete the pressing.

7. The high-precision multi-layer lamination and alignment PCB printing process according to claim 1, characterized in that: Before the laminate is sent into the lamination chamber, the resin molecules in the prepreg inside the laminate are vibrated by a resonance device to achieve directional alignment.

8. The high-precision multi-layer lamination and alignment PCB printing process according to claim 6, characterized in that: In the second pressing stage, the pressing head generates a dynamic magnetic field through the superconducting coil, thereby increasing the filling rate of the resin in the gaps between the plate layers. The pressing head also has a built-in pressure pad ceramic array, which emits shear waves during the pressing process to directionally soften the resin and reduce flow resistance.

9. The high-precision multi-layer lamination and alignment PCB printing process according to claim 1, characterized in that: During the substrate pretreatment stage, a liquid metal composite film is inserted and laid between each semi-cured sheet. During the second pressing stage of S3, the composite film is heated to liquefy and form a nano-scale slip layer, allowing each layer to produce a compensatory displacement of less than 10 microns under pressure. During the finished product output stage, it is instantaneously solidified after cooling, locking the layer position inside the finished board body to effectively reduce warping.