A circuit package structure and a method for manufacturing the same

Abstract

The application discloses a circuit packaging structure and a preparation method thereof. The circuit packaging structure comprises a substrate, an electronic component arranged on the substrate, a cover plate arranged on the substrate and used for protecting the electronic component, a first protrusion arranged on a surface of the cover plate and used for contacting an edge area of the substrate, a metal foil fixed to a surface layer of the substrate, arranged in a contact area of the substrate and the cover plate, and located in the edge area of the substrate, and extending to a bottom position of the first protrusion contacting the substrate from a side of the metal foil facing a center of the substrate and abutting against the bottom of the first protrusion, and a sealing glue arranged in a gap between the metal foil and the cover plate and used for sealing. The application has a protrusion and metal foil double protection system, reduces the risk of a pry piece directly contacting the edge area of the substrate and the electronic component near the edge area, and greatly reduces product scrap rate and production cost caused by rework.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printed circuit, in particular to a circuit packaging structure and a preparation method thereof. BACKGROUND

[0002] In the field of printed circuit manufacturing and application, lid-substrate packaging (combination of cover plate and substrate packaging, referred to as Lid-Substrate packaging) can provide reliable protection for internal IC chips and other electronic components, effectively isolate dust, moisture and mechanical impact from the outside, and become the mainstream packaging form of various high-end integrated circuit products, and is widely used in electronic devices with high reliability requirements.

[0003] In the production and testing process of integrated circuits and subsequent maintenance process, rework operation for lid-substrate packaging integrated circuits is very common. One of the core steps of such rework is to separate the cover plate from the substrate by prying, so as to detect, repair or replace the internal IC chip or other electronic components, thereby ensuring product yield and subsequent use requirements.

[0004] At present, in the existing lid-substrate packaging integrated circuit, the cover plate and the substrate are usually fixed by relying on the colloid, and no protection structure is provided for rework operation. This design leads to that when the cover plate is separated by using a pry, the pry is easy to directly contact the surface of the substrate or other electronic components on the substrate, which not only scratches and damages the precise circuit layer on the surface of the substrate, causing the substrate to be directly scrapped, but also deforms and damages the electronic components due to the contact with the electronic components on the substrate which are small in size and fragile in structure. These problems not only seriously affect the performance and subsequent use reliability of the integrated circuit, but also greatly increase the rework cost and product failure rate. Therefore, designing a lid-substrate packaging integrated circuit structure which can effectively block the contact of the pry during rework and prevent the substrate and electronic components from being scratched and damaged, has become a technical problem to be solved by the current technical personnel in the field. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a circuit packaging structure and a preparation method thereof.

[0006] In a first aspect, the circuit packaging structure provided by the present application adopts the following technical scheme:

[0007] The circuit package structure comprises a substrate, an electronic component arranged on the substrate, a cover plate arranged on the substrate for protecting the electronic component, a first protrusion arranged on a surface of the cover plate facing the substrate, the first protrusion protruding from the surface of the cover plate and being in contact with an edge area of the substrate, a metal foil fixed to a surface layer of the substrate, arranged in a contact area of the substrate and the cover plate and located in the edge area of the substrate, the metal foil extending to a bottom position of the first protrusion in contact with the substrate from a side of the metal foil facing a center of the substrate and abutting against the bottom of the first protrusion, and a sealing glue arranged in a gap between the metal foil and the cover plate for sealing.

[0008] By adopting the above technical scheme, in view of the problem that, in the existing rework process of the package integrated circuit with the cover, the pry piece directly contacts the circuit layer on the surface of the substrate or the fragile electronic component, causing damage to the circuit and the electronic component, a first protrusion + metal foil double protection system is constructed, the first protrusion is in contact with the pry piece first when the cover is pryed, and the pry piece is prevented from further penetrating into the substrate direction by the structure of the first protrusion, reducing the risk of the pry piece directly contacting the edge of the substrate and the electronic component near the edge, forming a first protective barrier; the metal foil fills the gap between the substrate and the cover plate on one hand, and on the other hand, the metal foil extends to the bottom of the first protrusion, so that even if the pry piece breaks through the first protrusion, the pry piece will first contact the metal foil, the metal foil can withstand the scratching of the pry piece and buffer the impact force, reducing the damage to the circuit layer of the substrate, and the metal foil can also assist in improving the heat dissipation performance of the package, cooperating with the sealing effect of the sealing glue, ensuring the safety of the rework operation and the long-term protection effect of the package structure on the electronic component, greatly reducing the product scrap rate and production cost caused by rework.

[0009] Optionally, an edge of the metal foil near the center of the substrate and an edge of the first protrusion near the center of the substrate form an extension C on the surface of the substrate, and the extension C is 100 μm.

[0010] By adopting the above technical scheme, the extension of 100 μm ensures that the metal foil can completely cover the edge area of the substrate below the first protrusion, reduces the case that the pry piece directly contacts the substrate after breaking through the first protrusion due to insufficient coverage of the metal foil, further optimizes the protection range, and at the same time, the extension does not excessively occupy the installation space of the electronic component in the center of the substrate, balancing the protection effect and the space utilization rate of the substrate.

[0011] Optionally, the metal foil is a copper foil, and a thickness H0 of the copper foil is 50 μm to 100 μm.

[0012] By adopting the technical scheme, the copper foil has excellent flexibility and ductility, the thickness of 50-100 microns can ensure that the copper foil is not easy to break under the prying force when prying the cover, effectively buffers the impact, and can also adapt to the gap size between the cover plate and the substrate to prevent the cover plate and the substrate from being not tightly assembled due to the excessive thickness of the copper foil; meanwhile, the thermal conductivity of the copper foil can assist in heat dissipation of the electronic components in the package, solve the problem of insufficient heat dissipation efficiency of the existing package relying on the cover plate, and ensure the long-term stable operation of the electronic components.

[0013] Optionally, the height H1 of the first protrusion in the direction perpendicular to the surface of the substrate is 50-100 microns, the first protrusion extends along the distribution direction of the edge of the substrate, and the width W1 of the first protrusion in the extension direction thereof is 200-500 microns.

[0014] By adopting the technical scheme, the height of 50-100 microns is designed to adapt to the conventional prying (thickness of about 50 microns), so that the prying can preferentially contact the first protrusion when the prying is inserted into the gap between the cover plate and the substrate, and the risk of directly contacting the substrate is reduced; the continuous structure surrounding the edge of the substrate and the width size of 200-500 microns make the first protrusion form a continuous protective barrier covering the entire edge area of the substrate, prevent the prying from cutting into the substrate from the gap and scratching the substrate due to the lack of protrusion protection in the local area, and improve the comprehensiveness and reliability of the protection.

[0015] Optionally, the cover plate further comprises a second protrusion, the second protrusion is arranged on the side of the cover plate facing the substrate, the projection of the second protrusion in the vertical direction covers the upper surface of the metal foil, the second protrusion is arranged adjacent to the first protrusion and is more towards the center of the cover plate, the height H2 of the second protrusion in the direction perpendicular to the surface of the substrate is less than H1, and the width W2 of the second protrusion in the extension direction thereof is less than or equal to W1.

[0016] By adopting the technical scheme, the second protrusion as an auxiliary protection structure can further support the cover plate on the one hand, prevent the center area of the cover plate from being deformed due to gravity or slight external impact, and cause the cover plate to press the electronic components on the substrate; on the other hand, the design of the lower height and smaller size of the second protrusion can neither block the central electronic components of the substrate, nor provide secondary blocking for the prying when the first protrusion fails, thereby further reducing the risk of damage to the substrate and the electronic components.

[0017] Optionally, the height H2 of the second protrusion in the direction perpendicular to the surface of the substrate is 30-50 microns, the second protrusion extends along the distribution direction of the edge of the substrate, and the width W2 of the second protrusion in the extension direction thereof is 100-300 microns.

[0018] By adopting the above technical scheme, the height of 30-50 μm and the width of 100-300 μm enable the second protrusion to precisely fit the space inside the first protrusion, neither excessively contact the surface of the substrate to cause the cover plate to be assembled to be inclined, nor form continuous auxiliary support and protection. On the premise that the second protrusion must be arranged, the width is controlled to be 100-300 μm (rather than a larger size), which can meet the functional requirements while minimizing the amount of material used. The size range can reduce the structural weight without weakening the protection effect, reduce the problem of increased weight or rising cost of the cover plate caused by excessively large size, and balance the protection effect and the demand for lightweight structure.

[0019] Optionally, the cover plate material is copper alloy, and the first protrusion, the second protrusion, and the cover plate are an integral forming structure.

[0020] By adopting the above technical scheme, the copper alloy material has high strength and high thermal conductivity, which can ensure that the first protrusion is not easily deformed when subjected to the prying force of the prying piece during rework prying, and can quickly conduct heat from the inside of the package through the cover plate to improve the heat dissipation efficiency; the integral forming structure eliminates the connection gap between the protrusion and the cover plate, prevents the sealing glue from seeping into the gap to cause the protrusion and the cover plate to separate, reduces the assembly process, reduces the production error, ensures the accuracy of the position and size of the protrusion, and ensures the stability of the protection effect.

[0021] Optionally, the metal foil is in the form of a sheet that matches the edge profile of the substrate, is arranged at the edge area of the substrate, and has a chamfer at a position corresponding to the corner of the substrate; the side of the metal foil facing the center of the substrate forms a hollowed-out area that penetrates through the thickness of the metal foil, which is used to avoid the electronic elements arranged on the substrate.

[0022] By adopting the above technical scheme, the sheet structure matches the edge profile of the substrate, ensuring that the metal foil fully covers the edge contact area of the substrate; the chamfer at the corner prevents the metal foil from scratching the surface of the substrate or the sealing glue; the hollowed-out area precisely avoids the electronic elements at the center of the substrate, preventing the metal foil from contacting the electronic elements to cause short circuit or affect the welding reliability of the electronic elements, and balancing the protection effect of the metal foil and the normal working requirements of the electronic elements.

[0023] Optionally, the sealing glue includes at least one of epoxy resin, silicone resin, modified acrylic ester glue, or polyurethane-epoxy resin blended glue.

[0024] By adopting the technical scheme, various sealing glue materials can adapt to different application scene requirements: the epoxy resin has high bonding strength and is suitable for scenes with high requirements for packaging stability; the silicone resin has good temperature resistance and is suitable for integrated circuits in high-temperature working environments; the modified acrylic ester glue has fast curing speed and can improve production efficiency; the polyurethane-epoxy resin blended glue has flexibility and strength and is suitable for application scenes that may have slight vibration, ensuring that the sealing glue can effectively isolate external dust and water vapor and adapt to different use environments to ensure long-term reliability of the packaging structure.

[0025] In a second aspect, the application provides a preparation method of a circuit packaging structure, which adopts the following technical scheme:

[0026] A preparation method of a circuit packaging structure includes the following steps:

[0027] S1, selecting and pretreating a substrate required for circuit packaging, the substrate including a substrate, a cover plate, and sealing glue, wherein the integration and fixation of the metal foil and the substrate are completed synchronously during the pretreatment of the substrate, so that the metal foil as a whole is in the form of a sheet that is adapted to the edge profile of the substrate and covers the edge region of the substrate;

[0028] S2, using a CNC milling process to process a protective protrusion on the cover plate;

[0029] S3, packaging and assembling, the cover plate with the processed protective protrusion is buckled on the substrate, so that the protective protrusion abuts against the metal foil.

[0030] By adopting the technical scheme, in view of the technical problems of the existing cover-packaged integrated circuit that is prone to scratching the substrate and electronic components during rework and has a high scrap rate, steps S1, S2, and S3 are adopted to process the metal foil that is adapted to the edge of the substrate, precisely process the protective protrusion of the cover plate by CNC milling, and realize the abutment and assembly of the protrusion and the metal foil, thereby constructing the protrusion-metal foil protection foundation of the application. The precise process ensures the adaptability of the protective structure, and the stable cooperation of the two blocks prevents the substrate and components from being directly contacted by rework prying, thereby solving the defects of the prior art. At the same time, the process is simple and suitable for batch production, taking into account efficiency and cost, and ensuring that the packaging structure protection function is reliable and landed.

[0031] In summary, the application includes at least one of the following beneficial technical effects:

[0032] In view of the problem that, in the existing rework process of the integrated circuit with a cover, the pry piece directly contacts the circuit layer or fragile electronic elements on the surface of the substrate, causing damage to the circuit and electronic elements, a first protrusion + metal foil double protection system is constructed. The first protrusion will be in contact with the pry piece first when the cover is pryed, and the pry piece will be blocked from further penetrating into the substrate direction by the structure of the first protrusion, reducing the risk of the pry piece directly touching the electronic elements near the edge of the substrate, forming the first protective barrier. The metal foil fills the gap between the substrate and the cover on one hand, and on the other hand, the design of the metal foil extending to the bottom of the first protrusion ensures that even if the pry piece breaks through the first protrusion, it will first contact the metal foil. The metal foil can withstand the scratching and impact force of the pry piece, reducing the damage to the circuit layer of the substrate. At the same time, the metal foil can also assist in improving the heat dissipation performance of the package, cooperating with the sealing effect of the sealant, ensuring the safety of the rework operation and the long-term protection effect of the package structure on electronic elements, greatly reducing the product scrap rate and production cost caused by rework.

[0033] The extension of 100 microns ensures that the metal foil can completely cover the edge area of the substrate below the first protrusion, reducing the situation that the pry piece directly contacts the substrate after breaking through the first protrusion due to insufficient coverage of the metal foil, further optimizing the protection range. At the same time, the extension will not occupy too much installation space of the electronic elements in the center of the substrate, balancing the protection effect and the utilization rate of the substrate space.

[0034] The second protrusion as an auxiliary protection structure can further support the cover on one hand, preventing the central area of the cover from deforming due to gravity or slight external impact, causing the cover to press the electronic elements on the substrate. On the other hand, the design of its lower height and smaller size will not block the electronic elements in the center of the substrate, and can provide secondary blocking for the pry piece when the first protrusion fails, further reducing the risk of damage to the substrate and electronic elements. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a cross-sectional structure schematic diagram of a circuit package structure provided by the embodiments of the present application;

[0036] Figure 2 is a local structure schematic diagram of a circuit package structure provided by the embodiments of the present application;

[0037] Figure 3 is a top view structure schematic diagram of a cover of a circuit package structure provided by the embodiments of the present application;

[0038] Figure 4 is another local structure schematic diagram of a circuit package structure provided by the embodiments of the present application;

[0039] Figure 5 is another top view structure schematic diagram of a cover of a circuit package structure provided by the embodiments of the present application;

[0040] Figure 6 is another top view structural schematic diagram of the circuit packaging structure provided by the embodiment of the present application, which is about the cover plate;

[0041] Figure 7 is a flow chart of the manufacturing method of the circuit packaging structure provided by the embodiment of the present application.

[0042] Explanation of reference signs:

[0043] 1, substrate; 10, electronic component; 2, metal foil; 3, sealing glue; 4, cover plate; 41, first protrusion; 42, second protrusion. DETAILED DESCRIPTION

[0044] The following will be further explained in detail with reference to the accompanying drawings. Figures 1-7 The present application will be further explained in detail.

[0045] The embodiment of the present application discloses a circuit packaging structure. Referring to Figure 1 and Figure 2 , the circuit packaging structure comprises a substrate 1, an electronic component 10 arranged on the substrate 1; a cover plate 4 arranged on the substrate 1 for protecting the electronic component 10, one side of the cover plate 4 facing the substrate 1 is provided with a first protrusion 41, the first protrusion 41 protrudes from the surface of the cover plate 4 and is used for contacting the edge area of the substrate 1; a metal foil 2 fixed to the surface layer of the substrate 1, arranged in the contact area of the substrate 1 and the cover plate 4, and located in the edge area of the substrate 1, the side of the metal foil 2 facing the center of the substrate 1 extends to the bottom position of the contact between the first protrusion 41 and the substrate 1, and abuts against the bottom of the first protrusion 41; a sealing glue 3 arranged in the gap between the metal foil 2 and the cover plate 4, used for sealing.

[0046] It can be understood that, inside the surface of the cover plate 4 facing the substrate 1 direction (close to the center direction of the cover plate 4), a first protrusion 41 is arranged along the edge contour thereof, which, after the cover plate 4 and the substrate 1 are assembled, causes the edge of the cover plate 4 body (away from the substrate 1 direction) to form a certain gap with the surface of the substrate 1, when a pry piece is used for rework operation, the thickness of the pry piece is smaller than the thickness of the gap, the pry piece first contacts the first protrusion 41, the first protrusion 41 can block the pry piece from continuing to penetrate towards the center of the substrate 1, thereby preventing the pry piece from directly contacting or scratching the substrate 1 or the resistive electronic element 10 on the substrate 1; in addition, the area range of the metal foil 2 between the cover plate 4 and the substrate 1 and located in the area of the sealing glue 3 covers the outer edge of the substrate 1 and extends towards the center of the substrate 1 until it extends to the position of the first protrusion 41 and further extends a certain distance, during the fixing process of the cover plate 4 and the substrate 1 through the sealing glue 3, the metal foil 2 is tightly clamped between the first protrusion 41 and the substrate 1. On the one hand, the metal foil 2 has good flexibility and ductility, which can buffer the impact force of the pry piece on the substrate 1 during operation, on the other hand, even if the pry piece breaks through the block of the first protrusion 41, it will first contact the metal foil 2, and the material properties of the metal foil 2 itself can withstand the scratching of the pry piece, preventing the pry piece from directly acting on the surface of the substrate 1, further playing a role in protecting the substrate 1 and the electronic element 10 on the substrate 1. In addition, the metal foil 2 is not simply laid on the surface of the substrate 1, but is integrated and fixed through the substrate 1 build-up process, during the manufacturing process of the substrate 1, through processes such as lamination, pattern plating, etching, etc., the metal foil 2 is processed as part of the top layer metal wiring of the substrate 1, and its connection stability with the substrate 1 is much higher than that of the traditional laying method, which can prevent the metal foil 2 from falling off during rework or use; at the same time, the surface of the metal foil 2 is treated by solder mask windowing and electroless nickel immersion gold, which not only ensures effective abutment with the first protrusion 41, but also prevents surface oxidation, while playing a role in buffering the impact force of the pry piece and protecting the substrate 1, it can also assist in improving the packaging heat dissipation performance, providing additional protection for the stable operation of the internal IC chip and other heat-generating electronic elements 10.

[0047] Reference Figure 2 In an embodiment, the edge of the metal foil 2 close to the center of the substrate 1 forms an extension C on the surface of the substrate 1 with the edge of the first protrusion 41 close to the center of the substrate 1, preferably, the extension C is 100 μm, the metal foil 2 is a copper foil, and the thickness H0 of the copper foil is 50 μm-100 μm. The height H1 of the first protrusion 41 in the direction perpendicular to the surface of the substrate 1 is 50 μm-100 μm, the first protrusion 41 extends along the circumferential direction of the edge of the substrate 1, and the width W1 of the first protrusion 41 in the extension direction thereof is 200 μm-500 μm.

[0048] It can be understood that the extension amount of 100 μm ensures that the metal foil 2 can completely cover the edge area of the substrate 1 under the first protrusion 41, reduces the situation that the pry piece directly contacts the substrate 1 after breaking through the first protrusion 41 due to insufficient coverage of the metal foil 2, further optimizes the protection range, and at the same time, the extension amount does not excessively occupy the installation space of the electronic element 10 in the center of the substrate 1, balancing the protection effect and the space utilization rate of the substrate 1. The copper foil has excellent flexibility and ductility, and the thickness is 50 μm-100 μm, preferably, the thickness of the copper foil is 70 μm, which is greater than the thickness of the pry piece 50 μm, which can not only ensure that it can withstand the force of the pry piece without being easily broken when the pry piece is returned, effectively buffering the impact, but also can adapt to the gap size between the cover plate 4 and the substrate 1, preventing the cover plate 4 and the substrate 1 from being tightly assembled due to the excessive thickness of the copper foil; at the same time, the thermal conductivity of the copper foil can assist the heat dissipation of the packaged electronic element 10, solve the problem of insufficient heat dissipation efficiency of the existing package relying only on the cover plate 4, and ensure the long-term stable operation of the electronic element 10. The thickness of the pry piece is usually 50 μm, the thickness of the first protrusion 41 is set to 50 μm-100 μm, and the thickness of the copper foil is set to 50 μm-100 μm. After the cover plate 4 and the substrate 1 are assembled, a gap of about 90 μm-150 μm (the effect of the sealant 3 will compress the copper foil) will be formed between the edge of the cover plate 4 and the surface of the substrate 1, which can adapt to the conventional pry piece for returning work, ensure that the pry piece can preferentially contact the first protrusion 41 when inserted into the gap between the cover plate 4 and the substrate 1, and reduce the risk of directly contacting the substrate 1; the first protrusion 41 extends along the distribution direction of the edge of the substrate 1, and the width W1 in the extension direction thereof is 200 μm-500 μm. The width design not only ensures that the first protrusion 41 has sufficient structural strength to resist the force of the pry piece for returning work, preventing the protrusion from being deformed or broken due to excessive width, but also ensures that the effective contact area with the metal foil is ensured by the lower limit size of 200 μm, so that the abutment between the two is more stable, preventing local poor contact from causing protection failure; at the same time, the upper limit control of 500 μm can prevent the protrusion from excessively occupying the space on the surface of the substrate, leaving reasonable layout space for other structures in the edge area of the substrate, forming a complete protection barrier in cooperation with the continuous extension form, and improving the comprehensiveness and reliability of the protection.

[0049] Reference Figure 3 In an embodiment, the cover plate 4 has a rectangular structure, and the first protrusions 41 are arranged on the four edges of the rectangle, respectively. The first protrusions 41 on each edge continuously extend along the length direction of the corresponding edge, and the first protrusions 41 on adjacent edges form a preset gap at the corner of the rectangular cover plate 4. The gap is in the form of a right-angled notch adapted to the corner of the rectangle, and the notch width is 50 μm-100 μm. The first protrusions 41 on the four edges form a non-closed protection structure around the edge of the cover plate 4 as a whole.

[0050] It can be understood that during the assembly process of the packaging structure, the components such as the substrate 1 and the cover plate 4 can have certain dimensional tolerances or deformation due to thermal expansion and contraction. The existence of the gap can serve as a buffer space to prevent the first protrusions from being pressed and stuck due to slight deviations in the positions of the components or deformation, ensuring the smoothness of the assembly, and also relieving the internal stress of the structure caused by factors such as temperature changes, thereby improving the stability and durability of the packaging structure. In addition, during subsequent other process operations (such as sealant filling, wire connection, etc.), the gap can provide space for operation or accommodate related materials and structures, so that the packaging structure can have more functional designs while having a protective function, meeting the electrical connection, sealing and other needs of the circuit packaging in addition to protection. For example, when the sealant 3 is filled subsequently, the gap can serve as a flow channel for the sealant, reducing the accumulation of sealant at the corners to generate bubbles and improving the sealing reliability.

[0051] With reference to Figure 4 and Figure 5 In an embodiment, the cover plate 4 further comprises a second protrusion 42, which is arranged on the side of the cover plate 4 facing the substrate 1. The projection of the second protrusion 42 in the vertical direction covers the upper surface of the metal foil 2. The second protrusion 42 is arranged adjacent to the first protrusion 41 and is closer to the center of the cover plate 4. The height H2 of the second protrusion 42 in the direction perpendicular to the surface of the substrate 1 is less than the height H1 of the first protrusion 41. The width W2 of the second protrusion 42 in the direction of its own extension is less than or equal to the width W1 of the first protrusion 41.

[0052] It can be understood that, with reference to Figure 4 , the lower surface (the side facing the substrate 1) of the cover plate 4 is provided with both the first protrusion 41 and the second protrusion 42, which are closely adjacent in the direction parallel to the surface of the substrate 1. The first protrusion 41 is closer to the edge of the substrate 1, and its bottom abuts the upper surface of the metal foil 2. The second protrusion 42 is located on the side of the first protrusion 41 away from the edge of the substrate 1 and is located in the upper region of the metal foil 2 (i.e., the projection of the second protrusion 42 in the vertical direction partially or completely covers the upper surface of the metal foil 2). With reference to Figure 5 , the horizontal position relationship is shown, taking the center of the cover plate 4 as the reference. The first protrusion 41 is distributed along the edge of the cover plate 4, and the second protrusion 42 is located between the first protrusion 41 and the center of the cover plate 4, i.e., towards the center of the cover plate 4, forming a horizontal position progressive relationship of the edge of the cover plate 4, the first protrusion 41, the second protrusion 42 and the center of the cover plate 4.

[0053] With reference to Figure 4The height H1 of the first protrusion 41 (the vertical distance from the lower surface of the cover plate 4 to the bottom of the first protrusion 41) is greater than the height H2 of the second protrusion 42 (the vertical distance from the lower surface of the cover plate 4 to the bottom of the second protrusion 42). Since the first protrusion 41 needs to directly abut the metal foil 2 and the substrate 1, it needs to be high enough to ensure stable contact, while the second protrusion 42 is only an auxiliary structure, and a lower height can reduce interference with the electronic components 10 on the substrate 1, while adapting to the space above the metal foil 2, which itself has a thickness. H2 < H1 can ensure that the bottom of the second protrusion 42 does not exceed the height of the upper surface of the metal foil 2, compared to relying only on the edge support of the first protrusion 41, the second protrusion 42 can form an auxiliary support for the central region of the cover plate 4, effectively dispersing the pressure generated by gravity or slight external impact on the cover plate 4, preventing the center of the cover plate 4 from deforming downward and pressing the electronic components 10 on the substrate 1 (the center of the substrate 1 is the main setting area of the electronic components 10, not shown in the figure).

[0054] Referring to FIG. 5, by extending along the edge distribution direction of the cover plate 4, the difference in the extension length of the two is embodied, the length of the first protrusion 41 extending along the edge of the substrate 1 is L1, the length of the second protrusion 42 extending in the same direction is L2, and L1 ≥ L2. The first protrusion 41 needs to match the extension length of the metal foil 2 (the metal foil 2 is distributed along the edge of the substrate 1) to ensure full abutment, and the second protrusion 42 as an auxiliary structure, its extension length does not exceed the first protrusion 41, can accurately cover the key area above the metal foil 2 (such as near the gap between the metal foil 2 and the cover plate 4). In addition, the size W2 of the second protrusion 42 perpendicular to its extension direction is less than the corresponding size W1 of the first protrusion 41, and is distributed between the first protrusion 41 and the center of the cover plate 4. The size design in the circumferential direction makes it neither block the electronic components 10 in the center of the substrate 1 beyond the circumferential range of the first protrusion 41, nor form a "edge - near center" protection cooperation with the first protrusion 41. When the first protrusion 41 weakens due to abnormal conditions (such as sealant 3 failure, external force impact), it needs to be repaired or maintained by prying, the second protrusion 42 can form a secondary blocking structure inside the first protrusion 41, reducing the probability of the pry directly entering the center of the substrate 1 to contact the electronic components 10, while its position above the metal foil 2 can also reduce the damage of the pry to the connection area between the metal foil 2 and the substrate 1, further reducing the risk of damage to the substrate 1 and the electronic components 10.

[0055] Understandably, the size of W1 is set so that the first protrusion 41 provides sufficient lateral support area, which helps to enhance its contact stability with the metal foil 2 and improve its load-bearing capacity against external forces. At the same time, it provides reasonable space for the filling of sealant 3, which is conducive to the formation of a uniform and effective sealing layer between the protrusion and the substrate. The design of W2≤W1 allows the second protrusion 42 to play an auxiliary protective role while preventing excessive occupation of the inner space of the cover plate, reserving more layout space for electronic components 10 in the central area of ​​the substrate, and accommodating the packaging requirements of components of different sizes. The compatibility design of W2 and W1 (equal or slightly smaller) can form a stepped protective structure. When external forces are applied to the packaging edge, the two can work together to disperse stress, improve the impact resistance of the overall structure, and facilitate the control of dimensional accuracy through a unified benchmark during the processing, reducing the difficulty of production.

[0056] In one embodiment, the height H2 of the second protrusion 42 in the direction perpendicular to the surface of the substrate 1 is 30μm to 50μm, the second protrusion 42 extends in the circumferential direction of the edge of the substrate 1, and the width W2 of the second protrusion 42 in its own extension direction is 100μm to 300μm.

[0057] Understandably, in a preferred embodiment, the height of 30μm to 50μm and the size of 100μm to 300μm allow the second protrusion 42 to precisely fit the space inside the first protrusion 41. This prevents excessive contact with the surface of the substrate 1, which could cause the cover plate 4 to tilt during assembly. It also provides continuous auxiliary support and protection, while reducing the problem of increased weight or cost of the cover plate 4 due to excessive size. This balances the need for both protective effect and lightweight structure.

[0058] It should be noted that the shape of the circuit package structure may vary, such as... Figure 5 , Figure 6 These correspond to different circuit package structures:

[0059] Reference Figure 5 The cover plate 4 is provided with a first protrusion 41 and a second protrusion 42. The first protrusion 41 and the second protrusion 42 extend along a straight line and transition at a right angle, corresponding to a rectangular circuit package structure. At this time, "the circumferential direction of the first protrusion 41 or the second protrusion 42 along the edge of the substrate 1" is the straight direction of the four sides of the rectangle. The circumferential dimension specifically refers to the length of the four sides of the rectangle. In some embodiments, such as Figure 5 The diagram shows a second protrusion 42. The first protrusion 41, the second protrusion 42, and the cover plate 4 work together to provide enhanced protection for the substrate 1 and electronic components 10. In other embodiments, only the first protrusion 41 and the cover plate 4 are shown. The first protrusion 41 contacts the edge of the substrate 1, providing basic protection for the substrate 1 and electronic components 10.

[0060] Referring to Figure 6 , the first protrusion 41 and the second protrusion 42 extend along a curve without a right-angle transition, corresponding to a circular or elliptical circuit package structure, where the surrounding direction, i.e. the circumferential / elliptical circumferential curved surface direction of the circular or elliptical shape, refers to the arc length on the circumference or the elliptical circumference, and meanwhile, the first protrusion 41 and the second protrusion 42 are arranged adjacent to each other, and the surrounding direction of the circular or elliptical package can be configured only with the first protrusion 41 or with a combination of the first protrusion 41 and the second protrusion 42, so that the cooperation of the double protrusions with the edge of the substrate 1 further enhances the protection stability of the cover plate 4 to the substrate 1 and the electronic element 10, and adapts to the uniform stress requirement of the curved surface package.

[0061] In an embodiment, the cover plate 4 is made of copper alloy, and the first protrusion 41, the second protrusion 42 and the cover plate 4 are integrally formed.

[0062] It can be understood that the copper alloy material has high strength and high thermal conductivity, which can not only ensure that the first protrusion 41 and the second protrusion 42 are not easily deformed when subjected to the force of the pry piece during rework prying, but also quickly conducts heat from the inside of the package through the cover plate 4 to improve the heat dissipation efficiency; the first protrusion 41 and / or the second protrusion 42 can adopt a split structure, for example, the connection between the protrusion and the cover plate 4 is realized by welding, gluing and other processes, and in a preferred embodiment, an integrally formed structure can also be used to eliminate the connection gap between the protrusion and the cover plate 4, prevent the sealing glue 3 from seeping into the gap to cause the separation of the protrusion and the cover plate 4, reduce the assembly process, reduce the production error, ensure the accuracy of the position and size of the protrusion, and ensure the stability of the protection effect.

[0063] In an embodiment, the metal foil 2 is in the form of a sheet that is adapted to the edge profile of the substrate 1, and is arranged at the edge region of the substrate 1, and the metal foil 2 is provided with a chamfer (not shown in the figure) at the position corresponding to the corner of the substrate 1; one side of the metal foil 2 facing the center of the substrate 1 forms a hollowed-out region, and the hollowed-out region is arranged through the thickness direction of the metal foil 2, which is used to avoid the electronic element 10 arranged on the substrate 1; and the metal foil 2 is fixed to the substrate 1 by a substrate build-up process, specifically, after processing the core layer of the substrate 1, the ABF film (Ajinomoto Build-up Film) is laminated, photo-patterning (UV exposure + development) is performed, chemical copper plating is performed to form a conductive seed layer, patterned electroplating is performed to thicken to 50-100 μm, then film stripping etching is performed to form a sheet structure that is adapted to the edge of the substrate 1, and finally a solder resist layer is used to open a window to expose the surface of the metal foil 2, and the exposed surface is treated by chemical nickel-gold plating.

[0064] It can be understood that the sheet structure is adapted to the edge profile of the substrate 1, ensuring that the metal foil 2 fully covers the edge contact area of the substrate 1; the chamfered corners can prevent the sharp edges and corners of the metal foil 2 from scratching the surface of the substrate 1 or the sealing glue 3; the hollowed-out area precisely avoids the central electronic element 10 of the substrate 1, preventing the metal foil 2 from contacting the electronic element 10 and causing short circuit or affecting the soldering reliability of the electronic element 10, and the integrated fixation of the metal foil 2 and the substrate 1 is realized through the substrate build-up process, and the connection strength is much higher than that of simple laying, which can effectively resist the force of rework prying and prevent the metal foil 2 from falling off; the opening design of the solder mask layer ensures that the metal foil 2 can directly abut against the first protrusion 41, and the chemical nickel-gold plating treatment can prevent the surface of the metal foil 2 from oxidizing, prolonging its service life and improving the contact stability with the first protrusion 41.

[0065] In an embodiment, the sealing glue 3 comprises at least one of epoxy resin, silicone resin, modified acrylic resin glue, or polyurethane-epoxy resin blended glue.

[0066] It can be understood that various sealing glue 3 materials can adapt to different application scenario requirements: epoxy resin has high bonding strength and is suitable for scenarios with high packaging stability requirements; silicone resin has good temperature resistance and is suitable for integrated circuits in high-temperature working environments; modified acrylic resin glue has fast curing speed, which can improve production efficiency; polyurethane-epoxy resin blended glue has both flexibility and strength, which is suitable for application scenarios that may have slight vibration, ensuring that the sealing glue 3 can effectively isolate external dust and moisture and adapt to different use environments to ensure long-term reliability of the packaging structure.

[0067] The electronic module disclosed in the embodiments of the present application comprises the circuit packaging structure as in any of the above embodiments.

[0068] It can be understood that the electronic module integrates the circuit packaging structure with the functions of "double rework protection + efficient heat dissipation + reliable sealing", which can effectively control the prying of the substrate 1 circuit layer and the electronic element 10 during the production test or later maintenance and rework of the electronic module, greatly reducing the module scrap rate caused by rework, improving the rework success rate, and reducing production and maintenance costs; on the other hand, the copper foil assisted heat dissipation and the heat conduction characteristics of the copper alloy cover plate 4 of the packaging structure can quickly conduct the heat generated by the internal electronic element 10 of the module, reducing the impact of high temperature on the performance of the module; at the same time, the sealing glue 3 ensures that the internal environment of the module is not eroded by the external environment, so that the electronic module can work stably for a long time in various scenarios such as high-end consumer electronics and industrial control, and the packaging structure does not need to be greatly changed from the existing electronic module production process and is easy to integrate in batches.

[0069] As shown in Figure 7 The embodiments of the present application also disclose a manufacturing and rework detection method of a circuit packaging structure, comprising the following steps:

[0070] S1, selecting and pretreating the substrate required for circuit packaging, the substrate including a substrate 1, a cover plate 4 and a sealing glue 3, wherein the integration and fixation of the metal foil 2 and the substrate 1 is completed synchronously during the pretreatment process of the substrate 1, so that the metal foil 2 as a whole is in the form of a sheet adapted to the edge profile of the substrate 1 and covers the edge region of the substrate 1, and the performance and size of each substrate are ensured to meet the requirements of subsequent processing and assembly through targeted pretreatment, thereby providing basic components meeting the requirements for subsequent processing and assembly, specifically including:

[0071] S11, selecting the substrate 1, using exposure, development and etching process to manufacture inner layer power supply, ground (GND) and signal lines; drilling through holes (PTH) and metalizing the holes through chemical deposition and electroplating process to realize interlayer interconnection; using reflow soldering process to solder electronic components 10 (including IC chips, resistors, capacitors, etc.) at the preset pads of the substrate 1, and detecting the solder joints by AOI (automatic optical inspection) equipment after soldering to ensure that the solder joints are free of false soldering, bridging and missing welding defects, and meet the electrical connection reliability requirements of the electronic components 10 and the substrate 1;

[0072] S12, laminating ABF film on the surface of the substrate 1, performing photo-induced pore formation on the ABF layer through UV exposure and development to form micro blind holes, and then performing desmear treatment on the substrate 1 after pore formation, followed by chemical copper plating to form a conductive seed layer with a thickness of less than 1 μm, coating photoresist on the surface of the seed layer, and using a mask with a metal foil 2 pattern for exposure and development, wherein the mask pattern includes a sheet-shaped structure adapted to the edge profile of the substrate 1, a chamfer design corresponding to the corner of the substrate 1, and a hollow area towards one side of the center of the substrate 1, the area where the metal foil 2 is to be retained is protected with photoresist, the substrate 1 is placed in an electroplating tank for pattern electroplating, the copper layer in the protected area is thickened to a target thickness of 50 μm to 100 μm, the photoresist is removed after electroplating, and then the seed layer not protected is removed by etching to form a sheet-shaped metal foil 2 adapted to the edge profile of the substrate 1 and having a hollow area, ensuring that the metal foil 2 completely covers the edge region of the substrate 1 and avoids the electronic components 10;

[0073] S13, coating green solder resist ink on the surface of the substrate 1, using a mask to expose and develop the metal foil 2 area, removing the solder resist ink on the surface of the metal foil 2 to realize solder resist windowing, and performing chemical nickel-gold plating treatment on the exposed surface of the metal foil 2, with the nickel layer thickness controlled at 5 μm to 8 μm and the gold layer thickness controlled at 0.1 μm to 0.2 μm;

[0074] S14, select copper alloy material processing cover plate 4, cover plate 4 overall size and substrate 1 adaptation; the surface of the cover plate 4 is passivated, the passivation film thickness is controlled in 5-8 mu m, in order to improve the corrosion resistance, using flatness detector to detect the flatness of the side of the cover plate 4 facing the substrate 1, to ensure that the flatness error is less than or equal to 0.1 mm; select epoxy resin adhesive as sealing glue 3, test the viscosity and curing performance of the adhesive in advance, to ensure that it can meet the packaging sealing requirements;

[0075] S2, using CNC (Computer Numerical Control, computer numerical control) milling process to process the protective protrusion on the cover plate;

[0076] When operating, first fix the cover plate 4 on the workbench of the CNC machining equipment, calibrate the position of the cover plate 4 through the positioning device to ensure the machining accuracy; then along the four edges of the side of the cover plate 4 facing the substrate 1, process the first protrusion 41 structure, control the protrusion height to be 100 mu m (along the direction perpendicular to the surface of the cover plate 4), the width is 500 mu m (along the circumferential direction of the edge of the cover plate 4), if the cover plate 4 needs to set the second protrusion 42, the second protrusion 42 can be processed synchronously along the side of the first protrusion 41 close to the center of the cover plate 4 in the same CNC milling process, the height H2 of the second protrusion 42 is controlled to be 30-50 mu m, the circumferential size W2 is controlled to be 100-300 mu m, the protrusion size is monitored in real time during the processing process to ensure that the error is within the allowable range; after processing, check the integrity of the protrusion structure to ensure that the inner edge of the protrusion is flush with the inner edge of the cover plate 4, without burr, misplacement and other defects, laying the foundation for subsequent cooperation with copper foil and substrate 1.

[0077] S3, packaging assembly, the cover plate 4 with protective protrusion is buckled on the substrate 1, the protective protrusion is abutted with the metal foil 2, and the overall assembly of the circuit packaging structure is completed;

[0078] Specifically, it includes the following steps:

[0079] S31, coating sealing glue 3, using dispensing equipment to evenly apply epoxy resin adhesive on the edge area of the substrate 1, the glue coating width is controlled in a suitable range, to ensure that it can fill the gap between the cover plate 4 and the substrate 1 in the subsequent process, and ensure that it can fill the gap between the cover plate 4 and the substrate 1 in the subsequent process, and will not overflow and contaminate the electronic components 10;

[0080] S32, cover plate 4 buckling, through high-precision assembly equipment to buckle the cover plate 4 with protruding structure (first protrusion 41 and / or second protrusion 42) on the substrate 1, buckling accurate alignment position, make the protruding structure inside the cover plate 4 opposite to the copper foil surface, form 0-10 μm micro gap (the gap is used to reserve the shrinkage of sealant 3 after curing, reduce the internal stress of the structure after curing), after the sealant 3 is cured, the protruding structure inside the cover plate 4 abuts against the copper foil, finally makes the protruding structure and the surface of the substrate 1 form 90 μm-150 μm gap, adapt to the insertion requirement of subsequent rework pry piece;

[0081] S33, sealant 3 curing, put the assembled packaging structure into the oven, set the temperature to 120℃, bake for 30 min, make the epoxy resin adhesive fully cured, need to control the temperature uniformity in the oven during curing, reduce the influence of local high or low temperature on the curing effect, take out the packaging structure after curing, cool to room temperature naturally, thus complete the assembly of the cover packaging integrated circuit.

[0082] S4, rework test, verify the rework protection performance of the packaging structure;

[0083] First, prepare the test tool, select a stainless steel pry piece with a thickness of 50 μm, the size of the pry piece is adapted to the gap between the edge of the packaging structure, which meets the actual rework operation scene; then fix the assembled cover packaging integrated circuit on the test platform, ensure the stability of the structure; then slowly insert the stainless steel pry piece from the edge gap between the cover plate 4 and the substrate 1, gently pry the cover plate 4, during the prying process, the pry piece will first contact the protruding structure inside the cover plate 4, the protruding structure blocks the pry piece from further penetrating into the center of the substrate 1, effectively preventing the pry piece from directly contacting the substrate 1 and the electronic element 10; continue to apply slight force, when the pry piece breaks through the protruding structure, it will contact the copper foil surface, at this time the copper foil will bear the force of the pry piece, finally only a slight scratch appears on the surface of the copper foil, while the surface of the substrate 1 and the electronic element 10 are intact; after the test is completed, check the integrity of the packaging structure and the function of the electronic element 10, confirm that the rework operation does not damage the product, achieve the purpose of rework operation without damaging the product.

[0084] It can be understood that, in order to solve the technical problems of existing cover packaging integrated circuit rework easy to scratch the substrate and electronic elements and high scrap rate, through steps S1, the metal foil is processed to adapt to the edge of the substrate, step S2, the protruding structure of the cover plate is precisely processed by CNC milling, step S3, the protruding structure and the metal foil are assembled to abut, which constructs the protruding structure-metal foil protection basis of the present application, which not only ensures the adaptability of the protection structure by precise process, but also solves the defects of the prior art by the stable cooperation of the two to block the rework pry piece from directly contacting the substrate and the element, at the same time, the process is simple and suitable for mass production, which takes into account efficiency and cost, and ensures that the protection function of the packaging structure is reliable.

[0085] The above are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, and thus: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A circuit package structure, characterized by comprising: The application relates to a substrate (1) provided with electronic components (10); a cover plate (4) arranged on the substrate (1) for protecting the electronic components (10), one side of the cover plate (4) facing the substrate (1) is provided with a first protrusion (41) protruding from the surface of the cover plate (4) and used for contacting the edge area of the substrate (1); a metal foil (2) fixed to the surface layer of the substrate (1) and arranged in the contact area of the substrate (1) and the cover plate (4) and located in the edge area of the substrate (1), the metal foil (2) extends to the bottom position of the first protrusion (41) contacting the substrate (1) on the side facing the center of the substrate (1) and abuts against the bottom of the first protrusion (41), the edge of the metal foil (2) on the side close to the center of the substrate (1) forms an extension C on the surface of the substrate (1) with the edge of the first protrusion (41) on the side close to the center of the substrate (1), and the extension C is 100 mu m; and a sealant (3) arranged in the gap between the metal foil (2) and the cover plate (4) for sealing. The metal foil (2) is a copper foil, and the thickness H0 of the copper foil is 50-100 mu m. The height H1 of the first protrusion (41) in the direction perpendicular to the surface of the substrate (1) is 50-100 mu m, the first protrusion (41) extends in the distribution direction of the edge of the substrate (1), and the width W1 of the first protrusion (41) in the extending direction thereof is 200-500 mu m. The cover plate (4) further comprises a second protrusion (42) arranged on the side of the cover plate (4) facing the substrate (1), the projection of the second protrusion (42) in the vertical direction covers the upper surface of the metal foil (2), the second protrusion (42) is arranged adjacent to the first protrusion (41) and is closer to the center of the cover plate (4), the height H2 of the second protrusion (42) in the direction perpendicular to the surface of the substrate (1) is less than H1, and the width W2 of the second protrusion (42) in the extending direction thereof is less than or equal to W1.

2. The circuit package structure of claim 1, wherein, The height H2 of the second protrusion (42) in the direction perpendicular to the surface of the substrate (1) is 30-50 mu m, the second protrusion (42) extends in the distribution direction of the edge of the substrate (1), and the width W2 of the second protrusion (42) in the extending direction thereof is 100-300 mu m.

3. The circuit package structure of claim 1, wherein, The cover plate (4) is made of copper alloy, and the first protrusion (41), the second protrusion (42) and the cover plate (4) are integrally formed.

4. The circuit package structure of claim 1, wherein, ​ 5. The circuit package structure of claim 4, wherein, ​ 6. The circuit package structure of claim 5, wherein, ​ 7. The circuit package structure of claim 1, wherein, The metal foil (2) is in a sheet shape matching the edge profile of the substrate (1) as a whole, is arranged in the edge region of the substrate (1), and is provided with a chamfer at a position corresponding to the corner of the substrate (1); a hollowed region is formed on the side of the metal foil (2) facing the center of the substrate (1), and the hollowed region is arranged through in the thickness direction of the metal foil (2) to avoid the electronic element (10) arranged on the substrate (1).

8. The circuit package structure of claim 1, wherein, The sealing glue (3) comprises at least one of epoxy resin, silicone resin, modified acrylic ester glue or polyurethane-epoxy resin blended glue.

9. A method of fabricating a circuit package structure, characterized by: The method comprises the following steps: S1, selecting and pretreating a substrate required for circuit packaging, the substrate comprising a substrate (1), a cover plate (4) and a sealing glue (3), wherein the integration and fixation of a metal foil (2) and the substrate (1) are simultaneously completed in the pretreatment process of the substrate (1), so that the metal foil (2) is in a sheet shape matching the edge profile of the substrate (1) as a whole and covers the edge region of the substrate (1); S2, processing a protective protrusion on the cover plate (4) by using a CNC milling process; S3, packaging and assembling, buckling the cover plate (4) processed with the protective protrusion on the substrate (1) so that the protective protrusion abuts against the metal foil (2).

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