A packaging structure, a packaging method and a sensing device

Abstract

The application discloses a packaging structure, a packaging method and a sensing device, and aims to solve the problems of poor temperature drift performance and low mounting precision of the packaging structure. The application comprises the following steps: selecting a thermoplastic material and pushing the thermoplastic material to a first connecting side area of a substrate for injection molding to form a first base, and simultaneously injection molding a guide column; fixing a chip at a preset position on a second connecting side of the substrate; selecting a thermosetting material and pushing the thermosetting material to the second connecting side of the substrate for plastic encapsulation molding to form a second base, the second base covering and fixing the second connecting side of the substrate and the chip, and being fixed with an end surface of the first base. Through the first base and the second base, different material combinations and the guiding and positioning effect of the guide column can be used, so that the temperature drift performance of the sensing device is improved, and the mounting precision of the packaging structure is improved.

Description

Technical Field

[0001] This invention relates to the field of sensor packaging technology, and more specifically, to a packaging structure, packaging method, and sensing device. Background Technology

[0002] In related technologies, current sensing devices are key components for controlling the power of new energy vehicles and ensuring their safety.

[0003] Technicians believe that the electric motors and controllers of new energy vehicles are developing towards higher safety, higher electromagnetic compatibility levels, higher power density, and higher efficiency. Current sensing solutions are gradually evolving towards integration, miniaturization, and chip-based solutions, blurring the lines between modules and chips. With further iterations and upgrades in current sensing technology, coreless current sensing solutions, due to their advantages such as no magnetic saturation limitations, small size, light weight, low cost, and ease of integration, are particularly suitable for high-current and high-frequency scenarios, and are gradually replacing core-containing current sensing solutions.

[0004] However, the aforementioned coreless current detection scheme has the following drawbacks: Since there is no magnetic core to concentrate the magnetic field, the coreless sensor must be precisely aligned with the current-carrying conductor. Otherwise, any change in the relative position (e.g., spacing, centering) between the sensor and the conductor being measured will cause a change in the effective coupling coefficient, leading to output errors and reduced installation accuracy.

[0005] The above problems urgently need to be addressed.

[0006] The above-disclosed background information does not imply that the applicant accepts it as prior art. Summary of the Invention

[0007] This invention overcomes the shortcomings of low reliability in related technologies for sensing devices, and provides a packaging structure, packaging method and sensing device. By combining the first base and the second base separately, the structure and materials can be configured differently and cooperate with the guiding and positioning function of the guide column to improve the installation accuracy.

[0008] The present invention provides a packaging structure, including: a carrier component, the carrier component including a substrate, the substrate including a first connection side and a second connection side, a conductive pin fixed on the first connection side, the conductive pin extending along the length direction of the substrate on the side away from the substrate and protruding from the first connection side of the substrate, and a chip fixed on the second connection side of the substrate. A first base is fixed to the first connection side of the substrate, and the conductive pin protrudes from the first end of the first base away from the substrate. The first end of the first base extends outward to form at least one guide post. A second base is fixed to the second connection side of the substrate.

[0009] Optionally, the conductive pin is L-shaped, with the side of the conductive pin closer to the substrate being the assembly section of the conductive pin and the side of the conductive pin farther from the substrate being the extension section of the conductive pin. The assembly section is vertically fixed to the first connection side, and the assembly section is perpendicular to the extension section.

[0010] Optionally, the number of conductive pins is greater than or equal to three, the conductive pins are arranged in parallel and at equal distances, and a first hole for assembling the conductive pins is provided on the first connection side, the position and size of the first hole matching the position and size of the assembly section of the conductive pin.

[0011] Optionally, the guide post and the extended section of the conductive pin are arranged in the same direction, and the guide post and the extended section of the conductive pin cooperate to provide a positioning reference for the installation of the package structure.

[0012] Optionally, a second hole is formed in the edge region of the second connection side of the substrate, which extends through the substrate thickness direction and falls within the coverage area of ​​the second base. A gap is provided between the second hole and the chip arranged on the second connection side of the substrate.

[0013] A packaging method for preparing the aforementioned packaging structure includes the following steps: Select a substrate, process a first hole at a preset hole position on the first connection side of the substrate, and process a second hole at the edge region on the second connection side of the substrate. The assembly section of the conductive pin is assembled into the first hole and fixed. The extension section of the conductive pin extends outward along the length of the substrate. A thermoplastic material is selected and pushed to the first connection side area of ​​the substrate for injection molding to form a first base, and guide pillars are simultaneously injection molded. The chip is fixed at a preset position on the second connection side of the substrate; A thermosetting material is selected and pushed to the second connection side of the substrate for molding to form a second base. The second base covers and fixes the second connection side of the substrate and the chip, and is attached and fixed to the end face of the first base.

[0014] Optionally, after the assembly section of the conductive pin is fitted into the first hole and fixed, and the protruding section of the conductive pin extends outward along the length of the substrate, the method further includes: An adhesion promoter is sprayed onto the outer surface of the assembled conductive pins and the substrate.

[0015] Optionally, the step of selecting a thermoplastic material and pushing it to the first connecting side region of the substrate for injection molding to form a first base, and simultaneously injection molding a guide post, includes: The thermoplastic material is heated and softened to a flowable state, and then injected into the first connecting side area of ​​the substrate under high pressure.

[0016] Optionally, the step of selecting a thermosetting material and molding it onto the second connection side of the substrate to form a second base, wherein the second base covers and fixes the second connection side of the substrate and the chip, and is attached and fixed to the end face of the first base, includes: The thermosetting material is heated and melted into a liquid state, and then pushed to the second connection side of the substrate under low pressure; Liquid thermosetting material passes through the second hole and, after molding, forms a columnar locking structure within the second hole, which interlocks and fixes the second connecting side of the substrate to the second base.

[0017] A sensing device includes: a terminal control circuit board, wherein at least one of the aforementioned packaging structures is provided on the terminal control circuit board, a guide post is inserted and fixed to the terminal control circuit board, and the extended section of the conductive pin is welded or inserted and fixed to the terminal control circuit board and electrically connected to the terminal control circuit board. The second base is provided with a conductive bus for transmitting large currents and whose magnetic field can be sensed and collected by the chip.

[0018] Compared with the prior art, the beneficial effects of the present invention are: First, the guide post, in conjunction with the conductive pin, enables dual positioning assembly, which greatly improves the overall assembly alignment accuracy and ensures stable and reliable structural support strength. Secondly, the first base serves as a positioning support, enabling precise positioning during assembly and alleviating the problems of sensitive positional tolerance and large installation errors in the on-site installation of coreless current sensors, thereby improving installation accuracy. Thirdly, the first base and the second base are separately encapsulated, and each can be matched with a suitable molding material. The first base can be made into a high-precision positioning structure using a material with good rigidity and easy integral molding. The second base can be matched with an encapsulation material to take into account insulation protection and efficient heat dissipation while improving the temperature drift of the sensing device. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the first embodiment of the present invention.

[0020] Figure 2 This is an exploded view of the first embodiment of the present invention.

[0021] Figure 3 This is an exploded view of the carrier component according to the first embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the structure of the first base according to the first embodiment of the present invention.

[0023] Figure 5 This is a flowchart of the encapsulation method steps according to the first embodiment of the present invention.

[0024] Figure 6 This is a schematic diagram of the sensing device structure according to the first embodiment of the present invention.

[0025] Figure 7 This is a bottom view of the sensing device according to the first embodiment of the present invention.

[0026] Figure 8 This is the first embodiment of the present invention. Figure 7 Schematic diagram of the cross section at point A in the middle.

[0027] Figure 9 This is the first embodiment of the present invention. Figure 8 Enlarged view of section B in the middle.

[0028] In the picture: 1. First base; 11. Guide post; 2. Second base; 3. Supporting component; 31. Substrate; 311. First connecting side; 312. Second connecting side; 313. First hole; 314. Second hole; 32. Conductive pin; 321. Assembly section; 322. Extension section; 323. Recess; 4. Chip; 5. Terminal control circuit board; 6. Conductive bus. Detailed Implementation

[0029] 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 some embodiments of the present invention, and not all embodiments. 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.

[0030] It should be noted that in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Similarly, words such as "a" or "one" do not indicate a quantity limitation, but rather indicate the presence of at least one; "multiple" indicates two or more. Unless otherwise stated, words such as "before," "after," "below," and / or "above" are for illustrative purposes only and are not limited to a location or spatial orientation.

[0031] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0033] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0035] Among related technologies, coreless current detection structures have outstanding advantages such as no magnetic saturation limitations, small size, lightweight, low cost, and easy integration. They can be adapted to high current and high frequency operating scenarios and are now widely used in compact power equipment such as electric vehicles, automotive electronics, and server power supplies, gradually replacing traditional detection solutions containing magnetic cores.

[0036] However, technicians believe that conventional coreless current sensors still have many technical shortcomings. Their coreless structure cannot concentrate the target magnetic field and is easily affected by external stray magnetic fields, which leads to a decrease in detection accuracy. At the same time, the core chip is highly sensitive to temperature, and the coreless structure has limited heat dissipation conditions and the packaging structure is prone to delamination and internal stress, resulting in poor product temperature drift performance.

[0037] The aforementioned temperature drift characteristic refers to the inherent change characteristic of a sensor in which its output detection value, sensitivity, zero-point potential, and other key performance parameters spontaneously shift and change with the rise and fall of ambient temperature, while keeping the measured physical quantity constant.

[0038] Furthermore, coreless sensors are extremely sensitive to installation position tolerances. The relative positional deviation between the sensor and the current-carrying conductor will directly change the magnetic field coupling coefficient, further reducing the current detection accuracy and making it difficult to meet the high precision and high stability requirements of high-end automotive equipment.

[0039] To address the technical deficiencies of existing technologies, this invention proposes a packaging structure, packaging method, and sensing device. Specifically, a substrate is used to distinguish between a first connection side and a second connection side, where conductive pins and a chip are respectively arranged. A first base and a second base are correspondingly and tightly attached to each other on both sides of the substrate, achieving a combined full-coverage packaging of the entire substrate and the chip. Through a differentiated split packaging structure design, two sets of bases are formed by adapting packaging materials with different properties. The first base forms a stable positioning support structure, which effectively constrains the sensor assembly position and solves the problems of position tolerance sensitivity and accuracy decay caused by installation errors in coreless sensors. The existing coreless sensor is optimized by using a second base to completely encapsulate and protect the chip, using suitable packaging materials to achieve insulation protection and efficient heat dissipation, optimizing structural stress matching, and significantly improving the temperature drift performance of the sensor.

[0040] First Embodiment Please refer to Figures 1 to 4 This embodiment provides a packaging structure, packaging method, and sensing device.

[0041] The present invention provides a packaging structure, including: a carrier component 3, the carrier component 3 including a substrate 31, the substrate 31 including a first connection side 311 and a second connection side 312, the first connection side 311 is fixed with a conductive pin 32, the side of the conductive pin 32 away from the substrate 31 extends along the length direction of the substrate 31 and protrudes from the first connection side 311 of the substrate 31, and the second connection side 312 of the substrate 31 is fixed with a chip 4. A first base 1 is fixed to the first connection side 311 of the substrate 31. The conductive pin 32 protrudes from the first end of the first base 1 on the side away from the substrate 31. The first end of the first base 1 extends outward to form at least one guide post 11. A second base 2 is fixed to the second connection side 312 of the substrate 31.

[0042] For example, substrate 31 is a PCB board. Specifically, the aforementioned PCB board refers to the printed circuit board that carries the conductive pins 32 and the chip 4, serving as the assembly support base for the two side bases. The advantage of this setup is that it provides high PCB board dimensional accuracy, convenient circuit layout, and can precisely match the dual-sided split packaging structure, unifying the pin soldering and chip mounting processes.

[0043] The conductive pin 32 is arranged in an L-shape. The side of the conductive pin 32 closest to the substrate 31 is the assembly section 321 of the conductive pin 32, and the side of the conductive pin 32 away from the substrate 31 is the extension section 322 of the conductive pin 32. The assembly section 321 is vertically fixed to the first connection side 311, and the assembly section 321 is perpendicular to the extension section 322.

[0044] The number of conductive pins 32 is greater than or equal to three. The conductive pins 32 are arranged in parallel and at equal distances. The first connection side 311 has a first hole 313 for assembling the conductive pins 32. The position and size of the first hole 313 match the position and size of the assembly section 321 of the conductive pins 32.

[0045] For example, each first hole 313 is coaxially aligned with the corresponding single pin assembly segment 321, and the spacing between multiple pins remains uniform.

[0046] The guide post 11 and the extended section 322 of the conductive pin 32 are arranged in the same direction. The guide post 11 and the extended section 322 of the conductive pin 32 cooperate to provide a positioning reference for the installation of the package structure.

[0047] For example, the extension length of the guide post 11 is adapted to the extension length of the pin extension section 322, and synchronously docks with the terminal control circuit board 5.

[0048] The advantage of this setup is that the guide post 11 is responsible for physical positioning and the pin extension 322 is responsible for electrical connection. The two work together to reduce assembly position deviation and improve the sensitivity of position tolerance of the coreless sensor.

[0049] The first base 1 is made of thermoplastic material, and the second base 2 is made of thermosetting material.

[0050] Specifically, the thermoplastic material used in this application is Vicnyl R430NH from Kingfa Science & Technology, which is a 30% glass fiber reinforced semi-aromatic nylon PA10T. Its typical technical parameters are shown in Table 1.

[0051] Table 1 The typical injection molding process parameters are shown in Table 2:

[0052] Table 2 In addition, when molding thermosetting materials, high Tg, low modulus, and high thermal conductivity epoxy molding resin is used. At the same time, the CTE matching and elastic modulus between the molding resin and the molding resin used in the original chip are optimized, which can promote heat dissipation, reduce packaging stress, and improve the temperature drift characteristics of the sensor.

[0053] At this time, the pressure and temperature of the molding process are at a relatively low level, with a typical injection pressure of about 3-6 MPa and a typical temperature of about 175±10℃.

[0054] The thermosetting material used in this encapsulation solution is Hysol's GR60PT (98D69B24A) epoxy encapsulating resin. Its typical technical parameters are shown in Table 3.

[0055] Table 3 Specifically, a 2-3mm gap is reserved inside the second base 2. This gap will be completely filled with epoxy encapsulation resin. The 2-3mm thick high dielectric strength resin forms an insulating barrier between the charged component and external components at different potentials. It can also buffer the curing shrinkage stress of thermosetting resin and the tensile force caused by the thermal expansion difference of different materials under high and low temperature cycling, reducing stress and deformation at the welding positions of chip 4, substrate 31, and conductive pins 32. The epoxy encapsulation resin used has a dielectric strength of approximately 40kV / mm, and the creepage distance and clearance between the pins and the primary edge are much greater than 8mm, thus achieving a withstand voltage level far exceeding the industry standard of 3kV.

[0056] For example, the aforementioned thermoplastic material refers to a nylon polymer material that can be melted when heated, solidified when cooled, and integrally injection molded into a positioning structure; Thermosetting materials refer to epoxy resin materials that cannot be remelted after being heated and cured, and have stable insulation and thermal conductivity.

[0057] The advantage of this setup is that it adapts the functions of the two bases to different materials, the thermoplastic material ensures the positioning and molding accuracy, and the thermosetting material achieves insulation and heat dissipation protection for the chip, thus simultaneously solving installation errors and temperature drift defects.

[0058] A second hole 314 is formed in the edge region of the second connection side 312 of the substrate 31, which extends through the thickness direction of the substrate 31. The second hole 314 falls within the coverage area of ​​the second base 2, and a gap is provided between the second hole 314 and the chip 4 arranged on the second connection side 312 of the substrate 31.

[0059] Specifically, the second hole 314 is a locking hole, used to form a columnar locking structure during the injection molding stage of the second base 2, so as to firmly lock the substrate 31 inside the second base 2 after subsequent injection molding.

[0060] For example, the adhesive locking hole is opened in the blank area at the edge of the substrate 31, maintaining a safe distance from the chip 4, so as not to interfere with the chip 4 mounting and sensing operation.

[0061] The advantage of this design is that the resin passes through the locking hole to form an interlocking locking structure, which greatly improves the bonding force between the substrate 31 and the second base 2 and suppresses encapsulation delamination and voiding problems.

[0062] Please refer to Figure 5 A packaging method for fabricating a packaging structure, comprising the following steps: S101: Select substrate 31, process and form a first hole 313 at a preset hole position on the first connecting side 311 of substrate 31, and process and form a second hole 314 on the edge region of the second connecting side 312 of substrate 31. For example, the first hole 313 and the second hole 314 are precisely machined by CNC drilling, and the hole diameter and hole position tolerances match the assembly and sealing requirements.

[0063] The advantage of this setup is that prefabricated standard holes provide a reference for pin assembly and resin locking, ensuring consistency in subsequent molding processes.

[0064] S102: The assembly section 321 of the conductive pin 32 is assembled into the first hole 313 and fixed. The extension section 322 of the conductive pin 32 extends outward along the length of the substrate 31. For example, a positioning fixture is used to solder the assembly section 321 of the conductive pin 32 onto the PCB board to ensure the consistency and perpendicularity of the conductive pin 32 soldering. Laser soldering is used for the conductive pin 32, which is a 0.8mm*0.8mm square pin with an inner diameter of 1.2mm for the first hole 313. The soldering time for each solder joint is 2s~4s. CCD inspection is used for solder joint appearance inspection, and X-ray equipment is used for 100% inspection of voids in the through-holes, with a void requirement of <25%. The solder penetration rate is ≥75%. 305 alloy no-clean lead-free solder wire is used.

[0065] Additionally, please refer to Figure 9 The assembly section 321 of the conductive pin 32 has a protrusion at one end near the PCB board. The protrusion and the connection point of the assembly section 321 form a recess 323. The design of the recess 323 takes into account both the distance of solder flow and the venting effect, thus achieving the function of solder venting.

[0066] The principle of the above-mentioned welding venting is that the gap between the first hole 313 and the pin assembly section 321 will trap air and fumes generated by the evaporation of flux when heated. During the process of molten solder filling the gap, the recess 323 provides a channel for the internal gas to escape outward. The gas can be smoothly discharged along the recessed gap and will not be trapped inside the solder layer to form bubbles or voids. Without the recess 323, the gas trapped inside the solder will cause poor solder joints, fluctuations in conduction resistance, and easy cracking of the solder joints, directly affecting the long-term electrical reliability of the sensor.

[0067] In addition, the conductive pins 32 need to be cleaned before soldering to remove surface dirt and dust.

[0068] The aforementioned positioning fixture is a specialized clamping and limiting device used in assembly, injection molding, welding, and other processing steps to limit the placement and orientation of workpieces, and belongs to process auxiliary fixtures. The positioning fixture used in this application is a welding process fixture, which precisely holds the relative position of the conductive pin 32 and the first hole 313 when the substrate 31 and conductive pin 32 are placed, ensuring that the parallel spacing and insertion depth between the conductive pins 32 are uniform and that there is no displacement or shaking during the welding process; CCD inspection refers to an industrial vision camera that captures images of solder joints and automatically identifies defects such as solder joint size, misalignment, and solder overflow.

[0069] X-ray equipment refers to flaw detection equipment that uses X-rays to penetrate sheet metal and non-destructively inspect for internal voids and poor weld defects in weld joints.

[0070] The advantage of this setup is that it allows for tooling positioning and shape control, laser welding to control solder penetration, and dual-equipment full inspection and control of solder joint quality. Combined with the 323 venting and solder climbing structure in the recessed part, it completely avoids the risk of internal air bubbles and cold solder joints.

[0071] S103: Select a thermoplastic material and push it to the first connection side 311 area of ​​the substrate 31 for injection molding to form the first base 1, and simultaneously injection mold the guide post 11; For example, the thermoplastic injection temperature is adapted to the solder joint tolerance range, and the molding heat will not damage the laser solder joint of the pin.

[0072] The advantage of this design is that the base and guide post 11 are integrally injection molded, resulting in high dimensional accuracy, a robust positioning structure, and a one-step encapsulation process.

[0073] Please refer to Figure 4 S104: Fix the chip 4 at a preset position on the second connection side 312 of the substrate 31; The soldering surface of chip 4 is surface-mounted onto the unencapsulated, exposed second connection side 312. The soldering method is SMT (Surface Mount Technology), using SAC305 alloy solder paste printed on the second connection side 312. After the chip is mounted on the PCB, it is reflow soldered. Inspection is performed according to IPC-A-610 standard.

[0074] In addition, after welding is completed, X-ray sampling is used for inspection, and 3D AOI is used for visual inspection of the weld joints.

[0075] After chip soldering, PCB cleaning is required: Automated PCB cleaning equipment is used to achieve a cleanliness level of <0.5μg / cm³. 2 This is far below the 1.56 μg / cm³ cleanliness requirement for PCBA in IPC J-STD-001. 2 .

[0076] After cleaning, plasma cleaning is performed to further activate the surface energy of the surface to be packaged, reducing the risk of delamination at the interface between primary and secondary packaging.

[0077] Specifically, the aforementioned 3D AOI refers to a three-dimensional automated optical inspection device that scans the four surface-mount solder joints of a chip in three dimensions, accurately detecting minute soldering defects such as cold solder joints, misalignment, and bridging.

[0078] The cleanliness requirements for PCBAs in IPC J-STD-001 refer to the general specifications for controlling residual impurities in printed circuit board components in the electronics industry, which limit the maximum allowable content of flux and ionic impurities on the board surface.

[0079] Surface energy refers to the extra energy of molecules on the surface of an object compared to molecules inside. It directly reflects the ease with which a material surface can be bonded or wetted: the higher the surface energy value, the easier it is for resins and adhesives to spread evenly and adhere to the substrate surface; the lower the surface energy, the more the material repels the resin, and the more likely it is to develop pinholes, poor adhesion, or delamination.

[0080] For example, thermoplastic encapsulation is completed first, and then chip 4 is soldered to avoid the shortcoming that chip 4 is not resistant to high temperature and prevent the high temperature of injection molding from damaging the performance of chip 4.

[0081] The advantage of this setup is that the process sequence is optimized to protect chip 4; multi-stage cleaning and plasma activation enhance the surface energy of the interface, strengthen the bonding strength of primary and secondary encapsulation, and reduce the causes of delamination.

[0082] S105: A thermosetting material is selected and pushed to the second connection side 312 of the substrate 31 for molding to form a second base 2. The second base 2 covers and fixes the second connection side 312 of the substrate 31 and the chip 4, and is attached and fixed to the end face of the first base 1.

[0083] Specifically, the second base 2 after molding is in the shape of a symmetrical bump, and the chip 4 is symmetrically disposed in the second base 2, and the left and right symmetry axes of the second base 2 and the chip 4 coincide to balance the stress of the molding compound on the chip 4.

[0084] In addition, the sensitive surface of chip 4 is closely fitted to the interior of the second base 2.

[0085] For example, the low-pressure, low-temperature molding process results in gentle molding stress, preventing strain on the SMT solder joints between chip 4 and substrate 31. The advantage of this setup is that the symmetrical molding structure evenly disperses the curing stress, and the high thermal conductivity resin bonded to the four sensitive surfaces of the chip simultaneously achieves heat dissipation, insulation, and buffering, effectively reducing the drift amplitude at high and low temperatures.

[0086] The assembly section 321 of the conductive pin 32 is fitted into the first hole 313 and fixed. The extension section 322 of the conductive pin 32 extends outward along the length of the substrate 31. Then, the system further includes: An adhesive accelerator is sprayed onto the outer surface of the assembled conductive pins 32 and substrate 31.

[0087] The aforementioned adhesion promoter refers to an interfacial additive that enhances the adhesion between the resin and the PCB board surface and dissimilar materials such as metal leads.

[0088] The adhesion promoter used in this application is DuPont AP8000, which is used to increase the adhesion between the PCB board and the molding compound (thermoplastic and thermosetting materials), ensure the adhesion effect of the molding compound, avoid delamination and blistering during injection molding, and increase the overall strength and stability of the encapsulation.

[0089] For example, the adhesive accelerator is sprayed thinly and evenly without changing the original structural dimensions, only improving the interfacial adhesive activity.

[0090] The advantage of this setup is that it solves the problem of poor adhesive compatibility between metal, PCB, and two types of plastics, and inhibits delamination and hollowing after injection molding and long-term use from the source.

[0091] A thermoplastic material is selected and injected into the first connecting side 311 region of the substrate 31 to form a first base 1, and a guide post 11 is simultaneously injection molded, including: The thermoplastic material is heated and softened to a flowable state, and then injected into the first connecting side 311 region of the substrate 31 under high pressure.

[0092] For example, the heating temperature matches the material's melting range, and high-pressure filling ensures that the mold cavity is completely filled without any missing material.

[0093] The advantage of such arrangement lies in that the high-pressure injection molded structure is dense and free of pores, the guide post 11 has a small dimensional tolerance, and the assembly positioning reference has higher precision.

[0094] A thermoset material is selected and pushed to the second connection side 312 of the substrate 31 for plastic encapsulation molding to form the second base 2. The second base 2 covers and fixes the second connection side 312 of the substrate 31 and the chip 4, and is attached and fixed to the end face of the first base 1, which includes: The thermoset material is heated and melted into a liquid state, and is pushed to the second connection side 312 of the substrate 31 under low pressure; The liquid thermoset material passes through the second hole 314, and after plastic encapsulation molding, a columnar locking structure is formed in the second hole 314, so as to engage and fix the second connection side 312 of the substrate 31 into the second base 2.

[0095] The resin is pushed at low pressure and low speed, with gentle flow, and the glue locking holes and gaps of 2~3mm can be completely filled by the resin without bubbles or voids.

[0096] The advantage of such arrangement lies in that low-pressure molding reduces the internal stress of the package, the glue locking holes are engaged and locked to firmly fix the substrate 31, and the second base 2 completely wraps the chip 4, which achieves the dual effects of firm structure, insulation and heat dissipation.

[0097] Reference Figures 6 to 9 , a sensing device, comprising: a terminal control circuit board 5, at least one packaging structure is arranged on the terminal control circuit board 5, the guide post 11 is inserted and fixed with the terminal control circuit board 5, and the extending section 322 of the conductive pin 32 is fixed to the terminal control circuit board 5 by welding or insertion, and is electrically connected to the terminal control circuit board 5; A conductive busbar 6 for transmitting large current and allowing the magnetic field to be induced and collected by the chip 4 is arranged outside the second base 2.

[0098] Specifically, the above-mentioned terminal control circuit board 5 refers to the PCB main board carrying the whole machine control circuit. On the one hand, it receives the power supply and detection signals output by the conductive pins 32 of the packaging structure through insertion matching, and completes current value calculation, signal conditioning and communication with the whole vehicle system; on the other hand, it stably supplies the working voltage to the chip 4 inside the packaging structure, and is the main control carrier for external signal interaction and power supply transmission of the coreless current sensor.

[0099] The conductive busbar 6 refers to a metal conductor for conducting large current, which is assembled on the outer side of the second base 2. It carries the measured current during operation, and the current flows through the busbar to generate an induced magnetic field. The magnetic field signal can be captured and collected by the chip 4 inside the package, so as to realize coreless current detection.

[0100] Second Embodiment Unlike the first embodiment, this embodiment takes three conductive pins 32 as an example. The conductive pins 32 correspond to the power supply pin of chip 4, the signal output pin of chip 4, and the common ground pin, respectively. The three conductive pins 32 serve as power supply pins, supplying a stable operating voltage to the internal chip 4. Signal output pin: Transmits the detection electrical signal converted from the magnetic field sensed by chip 4 to the terminal control circuit board 5; The grounding common pin provides a potential reference and electrostatic discharge path for chip 4 and the signal circuit.

[0101] For example, each of the three conductive pins 32 has an independent conduction circuit, and they are insulated from each other, so as to realize the three electrical functions of power supply, signal transmission and grounding simultaneously.

[0102] The advantage of this setup is that the three independent pins have clear functions, the circuit loops do not interfere with each other, ensuring stable transmission of current detection signals and adapting to the standard Hall effect electrical wiring logic for coreless sensors.

[0103] In summary, this application has at least the following advantages: First, the secondary encapsulation structure formed by the first injection molding and the second molding, with its differentiated configuration of structure and materials, and the guiding and positioning function of the guide post 11, solves the problem of installation position error of the coreless current sensor. Secondly, before encapsulation, the PCB assembly is surface-treated by spraying a small amount of adhesive promoter to increase the adhesion between the PCB and the molding resin, ensure the adhesion effect of the molding resin, and reduce the risk of delamination. Third, the secondary encapsulation uses thermosetting materials as a coating layer to provide insulation, heat dissipation and protection for chip 4 and the circuit board, improving the product's temperature drift characteristics; chip 4 only undergoes a short-term high temperature, which can effectively reduce the risk of delamination. Fourth, low-stress packaging materials are used, and the CTE matching and elastic modulus of primary and secondary packaging materials are optimized to reduce packaging stress and improve product temperature drift characteristics.

[0104] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A packaging structure, characterized in that, The carrier component (3) includes a substrate (31), which includes a first connection side (311) and a second connection side (312). A conductive pin (32) is fixed on the first connection side (311). The conductive pin (32) extends along the length of the substrate (31) on the side away from the substrate (31) and protrudes from the first connection side (311) of the substrate (31). A chip (4) is fixed on the second connection side (312) of the substrate (31). A first base (1) is fixed outside the first connection side (311) of the substrate (31). The conductive pin (32) protrudes from the first end of the first base (1) away from the substrate (31). The first end of the first base (1) extends outward to form at least one guide post (11). A second base (2) is fixed to the second connection side (312) of the substrate (31).

2. The packaging structure according to claim 1, characterized in that, The conductive pin (32) is L-shaped. The side of the conductive pin (32) closest to the substrate (31) is the assembly section (321) of the conductive pin (32), and the side of the conductive pin (32) furthest from the substrate (31) is the extension section (322) of the conductive pin (32). The assembly section (321) is vertically fixed to the first connection side (311), and the assembly section (321) is perpendicular to the extension section (322).

3. The packaging structure according to claim 2, characterized in that, The number of conductive pins (32) is greater than or equal to three. The conductive pins (32) are arranged in parallel and at equal distances. The first connection side (311) has a first hole (313) for assembling the conductive pins (32). The position size of the first hole (313) matches the position size of the assembly section (321) of the conductive pin (32).

4. The packaging structure according to claim 1, characterized in that, The guide post (11) and the extended section (322) of the conductive pin (32) are arranged in the same direction. The guide post (11) and the extended section (322) of the conductive pin (32) cooperate to provide a positioning reference for the installation of the package structure.

5. The packaging structure according to claim 1, characterized in that, The second connection side (312) edge region of the substrate (31) has a second hole (314) that extends through the thickness direction of the substrate (31), and the second hole (314) falls within the coverage area of ​​the second base (2). There is a gap between the second hole (314) and the chip (4) arranged on the second connection side (312) of the substrate (31).

6. A packaging method, characterized in that, The preparation of the packaging structure according to any one of claims 1-5 includes the following steps: Select a substrate (31), process a first hole (313) at a preset hole position on the first connection side (311) of the substrate (31), and process a second hole (314) at the edge area of ​​the second connection side (312) of the substrate (31). The assembly section (321) of the conductive pin (32) is correspondingly assembled inside the first hole (313) and fixed. The extension section (322) of the conductive pin (32) extends outward along the length direction of the substrate (31). A thermoplastic material is selected and pushed to the first connection side (311) area of ​​the substrate (31) for injection molding to form a first base (1), and a guide post (11) is simultaneously injection molded. The chip (4) is fixed at a preset position on the second connection side (312) of the substrate (31). A thermosetting material is selected and pushed to the second connection side (312) of the substrate (31) for molding to form a second base (2). The second base (2) covers and fixes the second connection side (312) of the substrate (31) and the chip (4), and is attached and fixed to the end face of the first base (1).

7. The packaging method according to claim 6, characterized in that, The assembly section (321) of the conductive pin (32) is fitted into the first hole (313) and fixed. The extension section (322) of the conductive pin (32) extends outward along the length direction of the substrate (31). Then, the process further includes: An adhesive accelerator is sprayed onto the outer surface of the assembled conductive pins (32) and substrate (31).

8. The packaging method according to claim 6, characterized in that, The process of selecting a thermoplastic material and injecting it into the first connecting side (311) region of the substrate (31) to form a first base (1), and simultaneously injecting and molding a guide post (11), includes: The thermoplastic material is heated and softened to a flowable state, and then injected into the first connecting side (311) region of the substrate (31) under high pressure.

9. The packaging method according to claim 6, characterized in that, The selection of thermosetting material and its pushing onto the second connection side (312) of the substrate (31) for molding forms a second base (2). The second base (2) covers and fixes the second connection side (312) of the substrate (31) and the chip (4), and is attached and fixed to the end face of the first base (1), including: The thermosetting material is heated and melted into a liquid state, and then pushed to the second connection side (312) of the substrate (31) under low pressure. The liquid thermosetting material passes through the second hole (314) and, after molding, forms a columnar locking structure in the second hole (314) to lock the second connecting side (312) of the substrate (31) into the second base (2).

10. A sensing device, characterized in that, include: The terminal control circuit board (5) is provided with at least one packaging structure as described in any one of claims 1-5. The guide post (11) is inserted and fixed to the terminal control circuit board (5). The extended section (322) of the conductive pin (32) is welded or inserted and fixed to the terminal control circuit board (5) and electrically connected to the terminal control circuit board (5). The second base (2) is provided with a conductive bus (6) for transmitting large current and whose magnetic field can be sensed and collected by the chip (4).

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