Composite cushioning press method and laminated structure for orthogonal backboard mother board

Abstract

A composite buffer pressing method and laminated structure for orthogonal backboard motherboards. The method comprises: providing an orthogonal backboard motherboard to be pressed; arranging a composite buffer laminated structure between the hot plate of the pressing machine and the motherboard, the structure comprising a first buffer layer and a second buffer layer from outside to inside, the first buffer layer being used for balancing the pressing pressure, and the second buffer layer being used for guiding the resin filling; and applying pressure and heat for pressing. The laminated structure comprises symmetrically arranged first and second buffer assemblies, each buffer assembly comprising a first buffer layer and a second buffer layer from outside to inside. The present application solves the problems of poor plate thickness uniformity and local glue filling difficulty in the pressing of the orthogonal backboard motherboard by the functional division and synergistic effect of the inner and outer double-layer buffer materials, can control the plate thickness range to be within 0.2 mm, realize the glue filling without cavity in the BGA area, and is suitable for the manufacturing of AI server orthogonal backboards with more than 78 layers and 10-30 mm in thickness.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board manufacturing technology, and in particular to a composite buffer lamination method and stacked structure for orthogonal backplane motherboards. Background Technology

[0002] Orthogonal backplanes are a key interconnect technology for next-generation AI servers, and their lamination process directly affects board thickness uniformity, expansion / contraction ratio, reliability, and adhesive filling effect. Three main challenges exist in the lamination process of orthogonal backplane motherboards: First, controlling board thickness uniformity is difficult. With dozens of layers and target thicknesses reaching tens of millimeters, and strict tolerances for interlayer dielectric layers, traditional lamination buffering methods struggle to achieve even pressure distribution on such thick boards, easily leading to excessive thickness differences between the board edges and the center. Second, the contradiction between insufficient and excessive adhesive is prominent. The surface of the orthogonal backplane motherboard contains numerous BGA areas and large copper-free areas. These areas are highly susceptible to insufficient or uneven adhesive filling during lamination, and traditional single-layer buffering materials cannot simultaneously achieve precise filling of high-density areas and uniform filling of large areas. Third, the unique material system presents process adaptation challenges. Orthogonal backplanes often employ high-grade copper-clad laminates combined with quartz fiber cloth reinforcement, resulting in significantly higher hardness than traditional FR-4 materials. Furthermore, interlayer bonding may utilize copper paste soldering, placing even stricter demands on temperature and pressure uniformity during the lamination process. While the impact of cushioning materials on multilayer PCB lamination has been studied, orthogonal backplane motherboards face the dual challenges of thickness uniformity and sufficient adhesive filling, making it difficult for a single cushioning solution to simultaneously meet both requirements. Existing single cushioning solutions (such as kraft paper, single PacoPad cushioning material, or three-in-one cushioning materials composed of aluminum sheet layers, cushioning paper layers, and release film layers) cannot simultaneously satisfy the dual requirements of thickness uniformity and localized adhesive filling for orthogonal backplane motherboards. Therefore, a lamination technology capable of simultaneously addressing these issues is urgently needed. Summary of the Invention

[0003] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a composite buffer lamination method for orthogonal backplate motherboards, comprising the following steps: Step S1: Provide the orthogonal backplate motherboard to be pressed; Step S2: A composite buffer stack structure is provided between the hot plate of the press and the orthogonal back plate mother plate. The composite buffer stack structure includes a first buffer layer and a second buffer layer from the outside to the inside. The first buffer layer is used to balance the pressing pressure, and the second buffer layer is used to guide the resin filling. Step S3: Apply pressure and heat to the composite buffer laminate structure to press the orthogonal backplate motherboard together.

[0004] This method utilizes a double-layer buffer structure to simultaneously address the dual problems of poor thickness uniformity and localized glue shortages during the lamination of ultra-thick orthogonal backplate motherboards. The first buffer layer homogenizes the hot plate pressure, while the second buffer layer adapts to the substrate surface morphology to guide resin flow. The synergistic effect of both layers allows the thickness variation to be controlled within 0.2 mm, ensuring that the BGA area is filled with glue without voids.

[0005] In a further embodiment, the first buffer layer is PacoPad buffer material, and the second buffer layer is a three-in-one buffer material composed of an aluminum sheet layer, a buffer paper layer, and a release film layer. PacoPad material possesses high compression resilience and high temperature resistance, effectively homogenizing pressure; the aluminum sheet layer provides uniform thermal conductivity, the buffer paper layer deforms to fill gaps, and the release film layer prevents sticking; the combination of these three elements guides resin filling. This material combination is a proven and preferred solution.

[0006] In a further embodiment, the composite buffer laminate structure also includes a release film and a steel plate. The release film is positioned between the second buffer layer and the steel plate, while the steel plate is positioned between the release film and the orthogonal backing plate. The release film prevents resin adhesion, and the steel plate acts as a rigid pressure transmission plate to ensure uniform pressure transmission. Together with the composite buffer layer, these components can further improve process stability and pressing quality.

[0007] In a further embodiment, the orthogonal backplate has 78 or more layers, with a target thickness of 10mm to 30mm. This embodiment limits the orthogonal backplate to an ultra-multi-layer, ultra-thick plate. Such extreme dimensions place extremely high demands on pressure uniformity, and the composite buffering method of this invention is particularly suitable for this scenario and can effectively overcome the uniformity problem.

[0008] In a further embodiment, the orthogonal backplate motherboard uses M9 grade copper-clad laminate combined with quartz fiber cloth as the substrate. The M9 grade Q cloth substrate has high hardness and requires strict uniformity of pressing. The composite buffer structure of the present invention can adapt to rigid substrates and provide uniform pressure distribution and sufficient adhesive filling.

[0009] In a further proposed solution, the lamination process employs a segmented lamination technique, comprising sequential heating, holding, and cooling stages. The pressure, temperature, and time for each stage are set based on the material properties of the orthogonal backplate motherboard. The segmented lamination, in conjunction with the composite buffer structure, controls resin flow and curing at different stages, improving the repeatability and process stability of the lamination quality.

[0010] In a further refinement, after lamination, the overall thickness variation of the orthogonal backplate motherboard is less than or equal to 0.2 mm, the internal expansion and contraction is less than or equal to 0.04 mm, and there are no voids in the filler adhesive in the BGA area. These indicators are the core criteria for the quality of the orthogonal backplate motherboard and can be directly verified through measurement and cross-sectioning. This method can reliably achieve these indicators, representing a significant improvement over existing technologies.

[0011] This invention also provides a composite buffer laminate structure for an orthogonal backplate motherboard, comprising: a first buffer assembly and a second buffer assembly symmetrically arranged, each including a first buffer layer and a second buffer layer arranged sequentially from the outside to the inside; wherein the first buffer layer is used to balance the pressing pressure, and the second buffer layer is used to guide resin filling. This symmetrical arrangement ensures uniform stress on the substrate, with the outer layer balancing pressure and the inner layer guiding the resin filling, thus simultaneously improving both the uniformity of board thickness and the integrity of the resin filling. As a product claim, it can be protected independently of the pressing method.

[0012] In a further embodiment, the first buffer layer is PacoPad buffer material, and the second buffer layer is a three-in-one buffer material composed of an aluminum sheet layer, a buffer paper layer, and a release film layer. This embodiment defines a preferred material combination: PacoPad provides pressure homogenization, while the three-in-one aluminum sheet, buffer paper, and release film provide thermal conductivity, deformation resistance, and anti-sticking functions, respectively, working together to guide resin filling.

[0013] In a further embodiment, each buffer assembly also includes a release film and a steel plate. The release film is positioned between the second buffer layer and the steel plate, while the steel plate is positioned between the release film and the orthogonal backplate motherboard. The orthogonal backplate motherboard has 78 or more layers, with a target thickness of 10mm to 30mm. Adding the release film and steel plate improves process convenience and pressure transmission uniformity, while limiting the orthogonal backplate motherboard to an ultra-thick, multi-layered board, thus clarifying the typical application scenarios for this structure.

[0014] The advantages of this invention compared to existing technologies are as follows: By arranging the first buffer layer (for balancing bonding pressure) and the second buffer layer (for guiding resin filling) in a specific order from the outside to the inside, this invention achieves, for the first time, synergistic optimization of macroscopic pressure uniformity and microscopic localized resin filling in orthogonal backplane motherboard bonding. Specifically, this composite buffering method can significantly reduce the overall board thickness variation from 0.5-1.0 mm in traditional methods to within 0.2 mm, control the amount of expansion and contraction within the board to within 0.04 mm, and ensure that the resin filling in the 0.8 mm pitch BGA area and the 50 mm × 50 mm large-size copper-free area is free of voids. This completely solves the problem of poor board thickness uniformity and localized resin deficiency in existing technologies, while meeting the differentiated bonding requirements of high-density BGA areas, large-size copper-free areas, and ordinary wiring areas. In addition, the composite buffering material has excellent temperature resistance and compression resilience, can be reused multiple times, has a wide process window, and high stability. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart of a composite buffer pressing method for an orthogonal backplate motherboard according to an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the composite buffer stacked structure according to an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Similar reference numerals and letters in the drawings indicate similar items; once an item is defined in one drawing, it does not need to be repeated in subsequent drawings. Terms such as "upper," "lower," "left," "right," "vertical," and "horizontal" indicate orientations or positional relationships based on the drawings or common understanding, and are used only for description, not to indicate or imply that the device must have a specific orientation. Where there is no conflict, the embodiments and features of the present invention can be combined with each other.

[0019] The invention will now be described in detail with reference to the actual lamination process of the orthogonal backplane motherboard. Orthogonal backplane motherboards are commonly used in high-performance computing devices such as AI servers. They can have dozens of layers and a thickness of tens of millimeters, and are typically made of M9 grade copper-clad laminate combined with quartz fiber cloth (Q cloth). The lamination process is carried out in a vacuum laminator. Heating and pressure are applied by hot plates, causing the prepreg or bonding material between the layers to melt, flow, and solidify, bonding the layers together. The parallelism tolerance of the upper and lower hot plates of the vacuum laminator should be controlled within 0.05 mm / m, and the vacuum degree of the lamination chamber should be below -0.095 MPa to prevent air bubble residue.

[0020] In one embodiment, an orthogonal backplane motherboard to be pressed is provided. This orthogonal backplane motherboard has completed pre-processing such as inner layer circuitry fabrication and browning treatment, with 78 layers and a target thickness of 15mm. The substrate is M9 grade copper-clad laminate, and the reinforcing material is quartz fiber cloth. On the lower hot platen of the press, a layer of PacoPad cushioning material is first laid as the first cushioning layer. PacoPad cushioning material is a commercially available high-performance cushioning pad with high compression resilience (compression ratio between 40% and 60%, rebound rate not less than 85%) and good heat resistance (maximum operating temperature up to 246°C), capable of evenly dispersing the local pressure of the press's hot platen across the entire board surface. The thickness of the first cushioning layer should be greater than or equal to the thickness of the second cushioning layer to ensure sufficient pressure buffering stroke. If the thickness of the first cushioning layer is much greater than the second cushioning layer (e.g., more than 5 times), the excessively long pressure buffering stroke may lead to a lag in pressure transmission response; if the thicknesses are equal or close, the synergistic effect is optimal. Those skilled in the art can adjust this according to the board thickness and material hardness. In other embodiments, multi-layered composite silicone rubber pads or high-density polyurethane cushioning pads can be used instead of PacoPad, as long as they can maintain elasticity and not be permanently deformed under high temperature and high pressure.

[0021] Above the first buffer layer, a three-in-one buffer material is laid as the second buffer layer. This three-in-one buffer material is a multi-layered structure composed of an aluminum sheet layer, a buffer paper layer, and a release film layer. The three-in-one buffer material consists of three layers: the bottom layer is an aluminum sheet layer, approximately 0.1-0.3 mm thick, which serves to conduct heat and provide rigid support; the middle layer is a buffer paper layer, approximately 0.2-0.5 mm thick, made of highly breathable kraft paper or fiber paper, capable of deforming under pressure to adhere to the substrate surface; the top layer is a release film layer, approximately 0.025-0.05 mm thick, made of polyethylene terephthalate or polytetrafluoroethylene, with a release agent coated on the surface to prevent resin adhesion. The total thickness of the second buffer layer should be set according to the maximum topographic difference on the substrate surface, typically to completely cover the BGA area protrusions and copper-free area depressions. The compression ratio of the buffer paper layer in the three-in-one buffer material should be higher than that of the first buffer layer to preferentially deform. The aluminum sheet layer can be replaced with other thermally conductive metal layers such as copper sheets, the cushioning paper layer can be replaced with a non-woven fabric layer or a felt layer, and the release film layer can also be a single-sided release film. A release film and a steel plate are then laid on top of the three-in-one cushioning material. The release film prevents resin overflowing during the pressing process from adhering to the steel plate, while the steel plate acts as a rigid pressure plate, evenly transmitting pressure to the substrate. The steel plate thickness is typically 1.5-2.0 mm, and its surface is mirror-polished to ensure flatness.

[0022] The orthogonal backplate mother plate to be pressed is placed on top of the steel plate. Then, following the principle of symmetry, PacoPad cushioning material, three-in-one cushioning material, release film, and steel plate are sequentially arranged above the orthogonal backplate mother plate, from the upper hot plate of the press towards the orthogonal backplate mother plate. The entire laminated structure from top to bottom is: upper hot plate, PacoPad cushioning material, three-in-one cushioning material, release film, steel plate, orthogonal backplate mother plate, steel plate, release film, three-in-one cushioning material, PacoPad cushioning material, and lower hot plate. This symmetrical configuration ensures that the stress on both sides of the substrate is completely consistent during pressing, avoiding warping.

[0023] The lamination process employs a segmented lamination technique. First, a heating phase begins: the press raises the temperature from room temperature to 120°C at a preset heating rate (e.g., 1.0-2.0°C / min) while applying low pressure (e.g., 5-10 kg / cm²), causing the resin in the prepreg to soften and begin to flow. In practice, the heating rate should be determined based on the resin's viscosity-temperature profile to avoid premature gelation of the resin due to excessively rapid heating, which would prevent the filling of large copper-free areas. At the end of the heating phase, the substrate's internal temperature is detected by thermocouples and automatically transitions to a holding phase once the preset gel point (typically the temperature at which the resin begins to crosslink) is reached. During this phase, the buffer paper layer in the three-in-one buffer material deforms under pressure, tightly adhering to the BGA and copper-free areas on the substrate surface, guiding the resin into the tiny gaps in these areas. Then, a holding phase begins: the temperature continues to rise to 180-200°C, and the pressure increases to medium-high pressure (e.g., 20-30 kg / cm²), maintained for 30-60 minutes to allow the resin to fully cure. During this stage, the PacoPad cushioning material evenly distributes the pressure, preventing pressure concentration caused by local thickness differences in the substrate. At the end of the heat preservation stage, the cooling stage begins once the exothermic curve of the resin curing reaction stabilizes or the predetermined heat preservation time is reached. Finally, the cooling stage involves gradually reducing the temperature and pressure, and releasing the pressure after cooling to room temperature. The parameters for each stage of segmented lamination can be adjusted according to the material properties of the orthogonal backing plate motherboard (such as the resin's gel time, curing temperature, and coefficient of thermal expansion). For example, when using a prepreg with a high Tg value, the maximum temperature can be set to 230°C.

[0024] After the outer PacoPad layer homogenizes the pressure, the inner three-in-one layer can effectively undergo local deformation within the uniform pressure field it provides, thereby guiding the filling material. If the order is reversed, the inner layer material cannot obtain uniform pressure, and its local deformation will deviate from the expected shape due to uneven pressure. This is the synergistic mechanism of the present invention.

[0025] In another implementation, the orthogonal backing plate can have a higher number of layers, such as 100 layers, with a target thickness of 25 mm. To further improve pressure uniformity, an additional pressure-equalizing plate, such as a 0.5 mm thick stainless steel sheet, can be added between the PacoPad cushioning material and the hot plate. Simultaneously, the cushioning paper layer in the three-in-one cushioning material can be increased to two layers to provide greater deformation capacity and adapt to more complex surface morphologies. For M9 grade Q-cloth substrates, due to their higher hardness, higher pressure (e.g., 35-40 kg / cm²) is required during lamination. Therefore, a high-elasticity model with a compression ratio of over 40% should be selected for the PacoPad cushioning material to ensure uniform pressure transmission.

[0026] In another embodiment, for an orthogonal backplane motherboard that does not require extremely high pressure (such as having fewer layers and a thinner thickness), some layers in the release film and steel plate can be omitted, and the PacoPad buffer material and the three-in-one buffer material can be directly used to contact the substrate. However, in order to facilitate demolding and protect the buffer material, it is generally still recommended to retain the release film. For an orthogonal backplane with fewer than 78 layers or a thickness less than 10 mm, the thickness of the first buffer layer and the second buffer layer can be appropriately reduced while maintaining the internal and external order unchanged.

[0027] For a recessed area with a depth exceeding 0.5 mm locally, a flexible compensation sheet (such as a polyimide film) with a thickness of 0.1 - 0.2 mm can be locally added between the second buffer layer and the orthogonal backplane motherboard to enhance the glue filling effect. This compensation sheet is not a necessary structure and is only selected in extreme cases.

[0028] After the lamination is completed, the orthogonal backplane motherboard is inspected. The thickness range and the amount of swelling and shrinkage data in this embodiment are obtained by testing the actual laminated samples. Use a micrometer with a precision of 0.01 mm to measure the thickness at at least 9 points on the board surface (including the center, four corners, and the midpoints of the four sides), and calculate the difference between the maximum value and the minimum value as the thickness range. For a 78-layer 15-mm-thick orthogonal backplane motherboard laminated by the above method, the measured thickness range of the whole board is 0.15 mm, which is better than the traditional solution (0.5 - 1.0 mm). The amount of swelling and shrinkage is obtained by measuring the change in the center distance of the preset φ1.0-mm target round holes at the four corners of the board surface. The measured amount of swelling and shrinkage inside the board is 0.03 mm, which meets the subsequent interlayer alignment accuracy requirements. Use X-ray to detect the BGA area, and there are no voids in the glue filling. These effects can be verified by microscopic observation after slicing. A thickness range ≤ 0.2 mm, an amount of swelling and shrinkage inside the board ≤ 0.04 mm, and no voids observed in the BGA area slice are regarded as qualified. If it exceeds this range, the thickness of the first buffer layer can be adjusted or the lamination parameters can be segmented and then laminated again.

[0029] If there is local thin thickness on the board surface after lamination, check whether the first buffer layer at the corresponding position is locally crushed, and replace the buffer material if necessary; if there are still voids in the BGA area, the heating rate can be appropriately reduced or the time of the heat preservation stage can be extended.

[0030] In a typical stacked configuration example, the following structure can be symmetrically arranged from the press hot platen towards the core layer: The outer layer consists of one or more steel plates, for example, several steel plates stacked together, each with a thickness of approximately 1.5-2.5 mm, to provide rigid support and uniform heat conduction. A layer of kraft paper, approximately 0.2-0.5 mm thick per sheet, and 3 to 8 sheets can be placed inside the steel plates to help buffer pressure fluctuations. Inside the kraft paper layer is the first buffer layer, i.e., the PacoPad cushioning pad, with a thickness of, for example, 0.89-1.4 mm. Inside the first buffer layer is the second buffer layer, i.e., a three-in-one cushioning material, with a total thickness of, for example, 0.1-0.5 mm. Inside the second buffer layer is a release film or barrier film, approximately 0.02-0.05 mm thick, to prevent the cushioning material from being squeezed into the holes. The innermost layer is the orthogonal backing plate mother plate to be pressed. The thickness and number of layers in this example are for illustrative purposes only and can be adjusted according to the plate thickness and material hardness.

[0031] In another, more detailed stack-up configuration, the following specific order from top to bottom can be used (in order to...). Figure 2 (Example shown): Cover plate; approximately 20 sheets of new kraft paper; first steel plate; high-temperature cushioning pad; second steel plate; first PacoPad cushioning layer; third steel plate; second PacoPad cushioning layer; three-in-one cushioning material layer; copper foil layer (e.g., copper foil used in the production of smooth steel); orthogonal backplate motherboard stack (e.g., composed of sub-plates L1-26, L27-52, L53-78 stacked sequentially); copper foil layer; three-in-one cushioning material layer; fourth PacoPad cushioning layer; fourth steel plate; fifth PacoPad cushioning layer; hot-dip galvanized steel plate; fifth steel plate; high-temperature cushioning pad; sixth steel plate; approximately 20 sheets of new kraft paper. In this configuration, each layer is symmetrically arranged around the orthogonal backplate motherboard. The number of steel plates, kraft paper sheets, and PacoPad layers can be adjusted according to actual needs. For example, 3-20 sheets of kraft paper, 1-3 steel plates, and 1-2 PacoPad layers can be used, and the specific values ​​are not limited to those mentioned above.

[0032] In another exemplary parameter setting, the following segmented control can be adopted (applicable to different resin systems or board thickness conditions): Preheating stage: temperature rises from room temperature to 130℃, pressure 5-10 kg / cm², time 20-30 min, allowing the resin to begin softening; Gelation stage: temperature 130-160℃, pressure 10-20 kg / cm², time 30-45 min, this stage is the critical filling period; Curing stage: temperature controlled at 160±5℃, pressure 20-25 kg / cm², time 60-90 min, allowing the resin to fully cross-link and cure; Cooling stage: temperature gradually decreases from 160℃ to 60℃, pressure 15-20 kg / cm², time 40-60 min, to reduce internal stress. It should be understood that the aforementioned example of heating to 120℃ and the current example of heating to 130℃ are both feasible parameter choices, and the specific parameters can be selected according to the specific material characteristics in actual production. Of course, the specific parameters should be adjusted according to the resin system and material characteristics used in the orthogonal backplate motherboard.

[0033] After lamination, in addition to the aforementioned thickness variation, shrinkage, and BGA filler tests, further inspections can be conducted on interlayer alignment and internal voids. Interlayer alignment can be checked using X-rays, with a pass rate of no more than 25 μm interlayer misalignment. Void detection can be performed using an ultrasonic scanning microscope, requiring no voids larger than 0.5 mm in diameter. These inspection indicators help to comprehensively evaluate the lamination quality.

[0034] It should be noted that all material thicknesses, quantities, process parameters, and testing indicators listed above are merely illustrative examples. Those skilled in the art can make reasonable selections based on actual production conditions, and are not limited to these specific values.

[0035] Those skilled in the art will understand that the function of the first buffer layer is to balance the compression pressure. This is not limited to using PacoPad brand materials; any buffer material with high compression resilience (compression ratio greater than 30%, rebound rate greater than 85%), high temperature resistance (long-term use temperature not lower than 200℃), and good surface smoothness can be used as a substitute. For example, multi-layer composite aramid paper pads or polyimide foam pads can be used. The function of the second buffer layer is to guide resin filling, and its core lies in providing a composite structure: a thermally conductive rigid layer, a compressible deformation layer, and an anti-sticking release layer. Therefore, in addition to the combination of aluminum sheet layer + buffer paper layer + release film layer, alternative combinations such as copper sheet + non-woven fabric + fluorine release film, or stainless steel foil + felt + silicone oil release film can also be used. The pressure-balancing function of the first buffer layer can be achieved using highly compressible and resilient materials (such as PacoPad, silicone rubber pads, and polyurethane pads); the guiding resin filling function of the second buffer layer can be achieved using composite materials with a deformable layer, a rigid layer, and a release layer (such as aluminum sheet + buffer paper + release film, copper sheet + non-woven fabric + fluorine release film). Regardless of the alternative material used, the first buffer layer must meet the following requirements: a compression ratio of not less than 30% and a resilience rate of not less than 85% under a pressure of 30 kg / cm² at 200°C, and a thermal conductivity of not less than 0.2 W / (m·K); the compressible deformable layer in the second buffer layer must have a higher compression ratio than the first buffer layer under the same conditions, and a permanent deformation rate of less than 5%. These alternative solutions all fall within the protection scope of this invention.

[0036] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A composite cushioning press method for a quad backplane motherboard, characterized by, Includes the following steps: Step S1: Provide the orthogonal backplate motherboard to be pressed; Step S2: A composite buffer stack structure is provided between the hot plate of the press and the orthogonal back plate mother plate. The composite buffer stack structure includes a first buffer layer and a second buffer layer from the outside to the inside. The first buffer layer is used to balance the pressing pressure, and the second buffer layer is used to guide the resin filling. Step S3: Apply pressure and heat to the composite buffer laminate structure to press the orthogonal backplate motherboard together.

2. The composite cushion press bonding method according to claim 1, wherein, The first buffer layer is PacoPad buffer material, and the second buffer layer is a three-in-one buffer material, which is composed of an aluminum sheet layer, a buffer paper layer and a release film layer.

3. The composite cushion press process of claim 1 wherein, The composite buffer stack structure further includes a release film and a steel plate. The release film is disposed between the second buffer layer and the steel plate, and the steel plate is disposed between the release film and the orthogonal back plate mother plate.

4. The composite cushion press process of claim 1 wherein, The orthogonal backplate motherboard has 78 or more layers and a target thickness of 10 mm to 30 mm.

5. The composite cushion press process of claim 1 wherein, The orthogonal backplate motherboard uses M9 grade copper clad laminate combined with quartz fiber cloth as the base material.

6. The composite cushion press process of claim 1 wherein, The pressing step adopts a segmented pressing process, which includes a heating stage, a heat preservation stage and a cooling stage performed sequentially. The pressure, temperature and time of each stage are set according to the material properties of the orthogonal backplate motherboard.

7. The composite buffer pressing method according to claim 1, characterized in that, After lamination, the thickness difference of the entire orthogonal backplate motherboard is less than or equal to 0.2 mm, the expansion and contraction within the board is less than or equal to 0.04 mm, and there are no voids in the filler glue in the BGA area.

8. A composite buffer laminate structure for orthogonal backplate motherboards, characterized in that, include: A first buffer assembly and a second buffer assembly are symmetrically arranged. Each of the first buffer assembly and the second buffer assembly includes a first buffer layer and a second buffer layer arranged sequentially from the outside to the inside. The first buffer layer is used to balance the pressing pressure, and the second buffer layer is used to guide the resin filling.

9. The composite buffer stacked structure according to claim 8, characterized in that, The first buffer layer is PacoPad buffer material, and the second buffer layer is a three-in-one buffer material, which is composed of an aluminum sheet layer, a buffer paper layer and a release film layer.

10. The composite buffer stacked structure according to claim 8, characterized in that, Each of the aforementioned buffer components further includes a release film and a steel plate, wherein the release film is disposed between the second buffer layer and the steel plate, and the steel plate is disposed between the release film and the orthogonal backplate mother plate; and the orthogonal backplate mother plate has a number of layers greater than or equal to 78 layers and a target thickness of 10 mm to 30 mm.

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