A process for improving the multilayer lamination performance of printed circuit boards

Abstract

This invention discloses a process for improving the multilayer lamination performance of printed circuit boards. By optimizing the curing kinetics of prepreg (PP) in the lamination process and using different lamination program settings for the inner layers, including reducing the heat preservation time during the high-temperature period of the lamination process, the curing degree of the inner layer resin is controlled to be reduced from 100% to 60-80% while ensuring that the processes and dimensional stability of the inner layer drilling, electroplating, and circuitry are not affected. When laminating the outermost layer, the original lamination program settings are restored, so that the curing degree of the inner and outer layer resins can be achieved to 100% in one lamination. This improves the overall lamination efficiency and enhances the material's resistance to multiple laminations.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board manufacturing technology, and in particular to a process for improving the multilayer lamination performance of printed circuit boards. Background Technology

[0002] Printed circuit boards (PCBs), as core components of modern electronic devices, have witnessed the rapid progress of the electronics industry throughout their technological development. Early PCBs relied on mechanical drilling to achieve interlayer connections, meeting basic circuit requirements at the time. As electronic devices evolved towards miniaturization and multi-functionality, High-Diameter Interconnect (HDI) boards emerged, employing laser drilling technology to process micro-blind vias, significantly increasing wiring density and integrating more components within a limited space, driving the miniaturization of electronic products. Today, Anylayer (AnyLayer Interconnect) technology has achieved a major breakthrough. This technology enables direct interconnection between any layers, greatly improving design flexibility and significantly enhancing signal transmission performance, providing solid support for the development of high-end electronic devices. It is suitable for the development needs of emerging technologies such as 5G base stations, artificial intelligence, and the Internet of Things.

[0003] Anylayer (any layer interconnect) printed circuit boards use a layer-by-layer stacking process. After each inner layer circuit is processed, a lamination process is required. Depending on the material characteristics, the processing time for a single lamination process is about 270 minutes, and the number of laminations increases as the number of product layers increases.

[0004] Let's take a 12-layer Anylayer board as an example, such as... Figure 3 As shown, a total of 5 pressing operations are required, as detailed below:

[0005] Taking FR-4 resin material as an example, the lamination bonding process settings and temperature profile are as follows: Figure 1 and Figure 2 As shown;

[0006] This process characteristic will directly lead to:

[0007] 1) Low production efficiency: The pressing production cycle is extended, and the equipment utilization rate is low;

[0008] 2) High quality risk: After multiple pressings, the inner dielectric layer resin has to undergo repeated high-temperature pressing treatments. The cumulative high-temperature time of multiple pressings can easily lead to over-curing of the resin, which in turn creates the risk of aging and can easily affect the reliability of the final product.

[0009] 3) Insufficient press capacity: The pressing process has become a production bottleneck, making it difficult to meet the industry trend of surging demand for high-end Anylayer products.

[0010] This invention addresses the aforementioned shortcomings by designing a method to improve the lamination efficiency of printed circuit boards and enhance the resistance of materials to repeated lamination. Summary of the Invention

[0011] To address the shortcomings of existing technologies, this invention provides a process for improving the multilayer lamination performance of printed circuit boards.

[0012] To achieve the above objectives, the present invention provides the following technical solution:

[0013] A process for improving the multilayer lamination performance of printed circuit boards involves using different lamination program settings for the inner layers, including reducing the heat preservation time during the high-temperature period of lamination, controlling the curing degree of the inner layer prepreg to decrease from 100% to 60-80%, and restoring the original lamination program settings during the outermost layer lamination, so as to achieve a 100% curing degree for the inner and outer layer prepregs in one lamination.

[0014] As a preferred embodiment of the present invention, further:

[0015] The aforementioned process for improving the multilayer lamination performance of printed circuit boards involves a maximum temperature of 210℃ during inner layer lamination, a holding time of 84 minutes, a heating rate of 1.5℃ / min, and a curing requirement of maintaining a temperature above 170℃ for 60 minutes. The curing target is for the prepreg to progress from stage A (original PP, curing degree 40%±5%) to stage B (curing degree 60-80%).

[0016] The aforementioned process for improving the multilayer lamination performance of printed circuit boards specifically involves pressure control during inner layer lamination as follows:

[0017] Initial pressure application phase (0-10 minutes): Apply 100 psi pressure to initially promote resin flow and start the filling process;

[0018] Accelerated filling stage (10-60 minutes): 300 psi pressure to accelerate resin flow and quickly fill interlayer voids;

[0019] Strengthening filling stage (60-80 minutes): 380 psi promotes the resin to fully fill the fine gaps and enhances the initial bonding between layers;

[0020] Stabilization and bonding stage (80-200 minutes): Maintain 450 psi to allow the resin to continue its cross-linking reaction, stabilizing and enhancing the interlayer bonding strength;

[0021] Stress release phase (200-225 minutes): The pressure drops to 200 psi, releasing the internal stress accumulated during the compression process.

[0022] The aforementioned process for improving the multilayer lamination performance of printed circuit boards involves a stepwise temperature increase (3℃ / min) to 240℃ during the outer layer lamination process, followed by a holding time of 130 minutes; a curing time of 190℃ or higher for 120 minutes; a gradient temperature decrease (3℃ / min → 220℃); and accelerated temperature decrease (220℃ → 70℃), followed by a holding time of 40 minutes; allowing both the inner and outer PP layers to cure to 100%.

[0023] The aforementioned process for improving the multilayer lamination performance of printed circuit boards involves pressure control during the outer layer lamination process:

[0024] Initial pressurization stage (0-6 minutes): Apply 100 psi pressure to initially promote resin flow, start the filling process, and create conditions for subsequent crosslinking reactions;

[0025] Accelerated filling stage (6-11 minutes): The pressure is increased to 200 psi to accelerate the resin flow rate and enable it to fill the gaps between PCB layers more quickly.

[0026] Enhanced filling stage (11-19 minutes): The pressure is further increased to 300 psi to enhance the resin filling effect, allowing the resin to more fully wet the material and strengthen the interlayer bonding.

[0027] Crosslinking promotion stage (19-27 minutes): Maintain 380 psi pressure to accelerate the resin crosslinking reaction, so that the material molecular structure gradually transforms into a network, thereby improving the physical and chemical properties of the PCB.

[0028] Stabilization and curing stage (27-167 minutes): Maintain 450psi pressure to ensure complete resin curing, ensure strong bonding between PCB layers, and stabilize electrical performance, etc.

[0029] Stress adjustment phase (167-237 minutes): The pressure is reduced to 200 psi, allowing the internal stress of the PCB to begin to adjust gradually, preventing damage to the internal structure due to continuous high pressure.

[0030] Stress release phase (237-274 minutes): The pressure is gradually reduced from 200 psi to 100 psi to fully release the internal stress accumulated during PCB pressing and prevent quality problems such as deformation and delamination.

[0031] The aforementioned process for improving the multilayer lamination performance of printed circuit boards can be adjusted between different pressure values ​​within one minute.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. Improve pressing efficiency

[0034] Shortening the single production cycle and reducing the time spent on each pressing reduces the overall production cycle. By shortening the single pressing time, the equipment can complete more batches of processing per unit time, thereby improving equipment utilization.

[0035] 2. Reduce quality risks

[0036] By shortening the processing time of the prepreg in a high-temperature and high-pressure environment, the time for the material to undergo high-temperature curing can be effectively reduced, thereby reducing the aging reaction caused by high temperature, significantly reducing the risk of material cracking, and improving the stability of product quality.

[0037] 3. Reduce lamination costs

[0038] Shortening the pressing time can reduce energy consumption and equipment depreciation costs, and reduce the defect rate and rework costs through process stability;

[0039] 4. Production capacity supply

[0040] By improving the pressing efficiency, the press can complete more pressing tasks per unit time, alleviating the problem of insufficient production capacity and meeting the market demand for high-end Anylayer products. Attached Figure Description

[0041] Figure 1 This is a production program table in the existing technology;

[0042] Figure 2 The temperature-time curve in the existing technology process;

[0043] Figure 3 This is a schematic diagram of the overall stacked structure of a 12-layer Anylayer board;

[0044] Figure 4 This is a schematic diagram of the inner layer lamination process;

[0045] Figure 5 This is a table of the inner layer lamination process in this application;

[0046] Figure 6 This is the inner layer bonding temperature-time curve in this application;

[0047] Figure 7 This is a comparison chart of the temperature-time curves of the existing process and that of this application. Detailed Implementation

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0049] This embodiment provides a process to improve the multilayer lamination performance of printed circuit boards. Different lamination program settings are used for inner layer lamination, including reducing the heat preservation time during the high-temperature period of lamination, controlling the inner layer resin lamination curing degree to decrease from the original 100% to 60-80%, and restoring the original lamination program settings during outermost layer lamination, so as to achieve 100% lamination curing degree of inner and outer layer resins in one go, thereby improving the overall lamination efficiency and improving the material's resistance to multiple laminations, as detailed below.

[0050] like Figure 3 As shown, taking a 12-layer Anylayer board and FR-4 resin material as an example:

[0051] 1. PP lamination and curing mechanism, such as Figure 4 As shown, the inner layers are laminated (L5 / L8→L4 / L9→L3 / L10→L2 / L11), with the inner layers laminated 4 times;

[0052] 1.1 Inner Layer Lamination Stage

[0053] During the inner layer lamination process, the resin softens and flows when heated, filling the gaps between layers; at this time, the degree of curing is controlled at 60-80%, the resin molecular chains are partially cross-linked, and a certain degree of fluidity is retained to meet the subsequent lamination requirements.

[0054] 1.1.1 Optimized temperature-time curve (see...) Figure 6 )

[0055] Key parameters: Maximum temperature 210℃, holding time 84 minutes, heating rate 1.5℃ / min, curing requirement: maintain above 170℃ for 60 minutes; (processing formula see...) Figure 5 );

[0056] Curing target: PP from stage A (original PP, curing degree 40%±5%) → stage B (curing degree 60-80%).

[0057] Pressure control:

[0058] Initial pressure application phase (0-10 minutes): Apply 100 psi pressure to initially promote resin flow and start the filling process;

[0059] Accelerated filling stage (10-60 minutes): 300 psi pressure to accelerate resin flow and quickly fill interlayer voids;

[0060] Strengthening filling stage (60-80 minutes): 380 psi promotes the resin to fully fill the fine gaps and enhances the initial bonding between layers;

[0061] Stabilization and bonding stage (80-200 minutes): Maintain 450 psi to allow the resin to continue its cross-linking reaction, stabilizing and enhancing the interlayer bonding strength;

[0062] Stress release phase (200-225 minutes): The pressure drops to 200 psi, releasing the internal stress accumulated during the compression process;

[0063] Note: Adjustments between different pressure values ​​can be completed within one minute;

[0064] 1.2 Outer layer lamination stage (L2-L11+L1 / L12)

[0065] During the outer layer lamination process, the manufacturing procedure in existing technologies, such as... Figure 1 As shown, the semi-cured states of stage A and stage B are pressed together; when the pressing temperature rises, the resin softens and flows to fill the gaps; with continuous heating, the resin molecules are fully cross-linked, changing from partially cross-linked to fully cross-linked stage C solid state (100% curing degree), so that the multi-layer material is firmly bonded into a whole.

[0066] 1.2.1, Outer layer temperature-time curve (e.g.) Figure 2 (As shown)

[0067] Key parameters: Stepwise heating (3℃ / min) to 240℃, hold for 130 minutes; curing requires maintaining above 190℃ for 120 minutes; gradient cooling (3℃ / min → 220℃); accelerated cooling (220℃ → 70℃), hold for 40 minutes; (see processing formula) Figure 5 )

[0068] Curing target: Stage B (60-80%) and the newly added Stage A PP are cured together to Stage C (100%).

[0069] Pressure control for outer lamination:

[0070] Initial pressurization stage (0-6 minutes): Apply 100 psi pressure to initially promote resin flow, start the filling process, and create conditions for subsequent crosslinking reactions;

[0071] Accelerated filling stage (6-11 minutes): The pressure is increased to 200 psi to accelerate the resin flow rate and enable it to fill the gaps between PCB layers more quickly.

[0072] Enhanced filling stage (11-19 minutes): The pressure is further increased to 300 psi to enhance the resin filling effect, allowing the resin to more fully wet the material and strengthen the interlayer bonding.

[0073] Crosslinking promotion stage (19-27 minutes): Maintain 380 psi pressure to accelerate the resin crosslinking reaction, so that the material molecular structure gradually transforms into a network, thereby improving the physical and chemical properties of the PCB.

[0074] Stabilization and curing stage (27-167 minutes): Maintain 450psi pressure to ensure complete resin curing, ensure strong bonding between PCB layers, and stabilize electrical performance, etc.

[0075] Stress adjustment phase (167-237 minutes): The pressure is reduced to 200 psi, allowing the internal stress of the PCB to begin to adjust gradually, preventing damage to the internal structure due to continuous high pressure.

[0076] Stress release phase (237-274 minutes): The pressure is gradually reduced from 200 psi to 100 psi to fully release the internal stress accumulated during PCB pressing and prevent quality problems such as deformation and delamination.

[0077] Note: Adjustments between different pressure values ​​can be completed within one minute.

[0078] The table below shows a comparison of data from conventional inner layer lamination and optimized lamination processes:

[0079]

[0080] In the inner layer lamination stage, the single lamination time is reduced from 274 minutes to 235 minutes (efficiency improvement of 14.2%), reducing the performance degradation of prepreg (PP) and improving the material's pressure resistance; ensuring uniform heating of the material, significantly reducing the risk of high-temperature curing accumulation from multiple laminations; increasing equipment utilization by more than 15% and reducing overall energy consumption by 20%, achieving both efficiency breakthroughs and quality enhancement.

[0081] Compared with the prior art, the process designed in this embodiment has the following advantages:

[0082] 1. Significantly improved efficiency

[0083] The single pressing time is shortened, and the outer layer pressing and holding time is reduced from more than 140 minutes in the original process to 120 minutes (a reduction of 14.2%), reducing the total production cycle by 30%.

[0084] Equipment utilization improved, the number of batches pressed per unit time increased by 11.7%, and the total pressing time for 12-layer boards decreased from 1375 minutes (5 times × 274 minutes) to 1214 minutes (4 times × 235 minutes + 1 time × 274 minutes).

[0085] 2. Quality risks are significantly reduced.

[0086] By shortening the high-temperature exposure time (the inner layer bonding temperature was reduced from 240℃ to 210℃, and the high-temperature holding time was reduced from 130min to 84min), the risk of resin cracking was greatly reduced.

[0087] 3. Cost and energy consumption optimization

[0088] The energy consumption for a single pressurization cycle has been reduced from 200 kWh to 150 kWh (a 25% reduction).

[0089] The process stability was enhanced, the yield increased from 90% to 97%, and rework costs were reduced by 70%.

[0090] 4. Breakthrough in production capacity

[0091] The press capacity has been increased from 1,000 pieces per month (original process) to 1,200 pieces per month (an increase of 20%), thereby increasing the shipment volume of high-end PCBs.

[0092] The foregoing has shown and described the basic principles and main features of the present invention and its advantages. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0093] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A process for improving the multilayer lamination performance of printed circuit boards, characterized in that, Different pressing program settings are used for inner layer lamination, including reducing the heat preservation time at the highest temperature during lamination, controlling the curing degree of the inner layer prepreg to decrease from 100% to 60-80%, and restoring the original pressing program settings during outermost layer lamination, so as to achieve 100% curing degree of inner and outer layer prepreg in one lamination. The highest temperature during inner layer lamination is 210℃, with a holding time of 84 minutes and a heating rate of 1.5℃ / min. Curing requires maintaining a temperature above 170℃ for 60 minutes. The curing target is for the prepreg to progress from stage A to stage B, where stage A is the original PP with a curing degree of 40% ± 5%, and stage B has a curing degree of 60-80%. The pressure control during inner layer lamination is specifically as follows: The initial pressure application phase lasts 0-10 minutes: apply 100 psi pressure to initially promote resin flow and initiate the filling process; The 10-60 minute period is the accelerated filling stage: 300psi pressure to accelerate resin flow and quickly fill interlayer voids; The 60-80 minute mark is the reinforcement and filling stage: 380psi promotes the resin to fully fill the fine gaps and enhances the initial bonding between layers; The 80-200 minute period is the pressure stabilization and bonding stage: maintain 450 psi to allow the resin to continue the cross-linking reaction, stabilize and improve the interlayer bonding strength; The 200-225 minute period is the stress release phase: the pressure drops to 200 psi, releasing the internal stress accumulated during the compression process.

2. The process for improving the multilayer lamination performance of printed circuit boards according to claim 1, characterized in that, During the outer layer lamination process, the temperature is gradually increased to 240℃ at a rate of 3℃ / min and held for 130 minutes; the curing process requires maintaining a temperature above 190℃ for 120 minutes; and the temperature is gradually decreased to 220℃ at a rate of 3℃ / min. Accelerate the cooling process from 220℃ to 70℃, and maintain the temperature for 40 minutes to allow both the inner and outer PP layers to cure to 100%.

3. The process for improving the multilayer lamination performance of printed circuit boards according to claim 2, characterized in that, Pressure control during the outer lamination process: The initial pressurization phase lasts from 0 to 6 minutes: 100 psi pressure is applied to initially promote resin flow, start the filling process, and create conditions for the subsequent crosslinking reaction. The 6-11 minute period is the accelerated filling stage: the pressure is increased to 200psi to accelerate the resin flow rate and make it fill the gaps between PCB layers more quickly. The 11-19 minute mark is the enhanced filling stage: the pressure is further increased to 300 psi to enhance the resin filling effect, allowing the resin to more fully wet the material and strengthen the interlayer bonding. 19-27 minutes is the cross-linking promotion stage: maintain 380psi pressure to accelerate the resin cross-linking reaction, so that the material molecular structure gradually transforms into a network, improving the physical and chemical properties of PCB; The 27-167 minute period is the voltage stabilization and curing stage: maintain a pressure of 450 psi to ensure complete resin curing, guarantee strong bonding between PCB layers, and stabilize electrical performance; The 167-237 minute period is the stress adjustment phase: the pressure is reduced to 200 psi, allowing the internal stress of the PCB to begin to adjust gradually, so as to avoid damage to the internal structure due to continuous high pressure. The stress release phase lasts from 237 to 274 minutes: the pressure is gradually reduced from 200 psi to 100 psi to fully release the internal stress accumulated during the PCB pressing process and prevent deformation and delamination quality problems.

4. The process for improving the multilayer lamination performance of printed circuit boards according to any one of claims 1-3, characterized in that, Adjustments between different pressure values ​​can be completed in one minute.

Images