Double-sided packaging structure of electronic products

Abstract

The invention discloses a double-sided packaging structure of an electronic product. The packaging structure of the invention comprises a packaging PCBA, a plastic package, an internal pin assembly, an external pin, a shell, and a bottom plate; wherein the PCBA is fixed with devices such as a power tube, a chip, a magnetic core, and an internal pin assembly; the upper and lower surfaces of the PCBA are integrally covered with the plastic package body through a plastic packaging process; after the plastic packaged product is cut and polished, the internal pin legs of the PCBA are leaked, and then the external pins are welded; the welded upper and lower surfaces of the PCBA are coated with thermal conductive silicone grease or thermal conductive glue, and loaded into the cavity formed after the shell and the bottom plate are assembled; before the shell and the bottom plate are assembled, solder paste needs to be applied in the groove of the stopper matched between the two, and high-temperature reflow soldering is used as a whole. The packaging structure of the invention has the advantages of small size, excellent heat dissipation, simple and reliable installation, high pin strength, superior shielding performance, good environmental adaptability, etc., and can improve the reliability of electronic products during use.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic packaging of electronic products, in particular to a double-sided packaging structure of electronic products. Background Art

[0002] In today's consumer electronics, automotive electronics, and the more demanding aviation, aerospace, and military industries, the requirements for electronic products to be miniaturized, modularized, high power density, highly integrated, and highly reliable are becoming increasingly high. Current high-power density PCBAs generally use potting glue for overall potting when heat dissipation is required, but potting glue has defects such as low thermal conductivity and inability to fill small spaces, which limits development prospects. At the same time, more and more PCBAs use chip microelectronic packaging technology and use thermosetting and thermoplastic materials to form modules. Although they can provide protection in terms of heat, mechanical properties, and isolation from the external environment within a certain range, they have limited protection in high power density and harsh use environments.

[0003] Products produced by the plastic encapsulation process generally use a bottom substrate or frame structure, which cannot cover the entire plastic encapsulation module. Plastic encapsulation modules under the existing technology generally use a single-sided conduction heat dissipation method when used by the client, which cannot overcome the defects of high thermal resistance and high temperature rise of the components on the other side of the PCBA. In addition, the common pins on the frame of the plastic encapsulation module are generally chip designs, which cannot meet the requirements of the fixing strength of the high-current and heavy-weight plastic encapsulation modules. Summary of the invention

[0004] The purpose of the present invention is to address the problems existing in the prior art, propose a double-sided packaging structure for electronic products, and provide a method for pin welding and outer surface covering of a metal shell after the electronic product is plastic-sealed, which can significantly improve the thermal resistance of the heat dissipation path, and has the characteristics of simple plastic sealing process, good heat dissipation effect, small size, easy installation, good environmental adaptability, high pin strength, high electromagnetic shielding performance, etc., thereby significantly improving the reliability of electronic products.

[0005] The technical solution for achieving the purpose of the present invention is: a double-sided packaging structure of an electronic product, including a PCBA, a base plate, a shell, a plastic package, an internal pin assembly and an external pin; wherein a power tube, a chip and a magnetic core that need heat dissipation are fixed on the PCBA, and an internal pin assembly is welded on the PCBA; the PCBA is installed in the cavity of the plastic package, and the upper and lower sides of the PCBA are wrapped by the plastic package; the plastic-sealed product module can be cut into a desired shape and polished to reveal the internal pin assembly, the internal pin assembly is riveted to the external pin, and reflow soldered; the plastic-sealed product module is installed in the shell, and the bottom surface of the shell is assembled with a base plate to fix the product module.

[0006] Furthermore, the internal pin assembly includes a pin cap and a pin leg, and a groove is provided at the middle position of the top of the pin leg. After the pin cap is welded, a sealed cavity is formed between the two, which is convenient for later welding of the external pin.

[0007] Furthermore, the plastic encapsulation body includes a plastic encapsulation lower mold and a plastic encapsulation upper mold arranged from bottom to top, the PCBA welded with an internal pin assembly is placed in the cavity of the plastic encapsulation lower mold, and the plastic encapsulation upper mold and the plastic encapsulation lower mold are molded together to press and fix the PCBA; a glue inlet is provided on the plastic encapsulation upper mold, and a glue inlet flow channel is provided in the plastic encapsulation upper mold and the plastic encapsulation lower mold, and the upper and lower sides of the PCBA are plastic encapsulated simultaneously through the glue inlet and the glue inlet flow channel to form a plastic encapsulated product module.

[0008] Furthermore, the bottom of the external pin is a square, and the groove on the top of the pin leg is a round hole; the four right angles of the square at the bottom of the external pin and the round hole are fixed by interference riveting and reflow soldering.

[0009] Furthermore, the upper and lower surfaces of the plastic-sealed product module are coated with heat-conducting material and then contact the housing and the bottom plate.

[0010] Furthermore, the shell and the base plate are fixed by solder paste and high-temperature reflow.

[0011] The assembly method of the packaging structure includes the following steps:

[0012] Step 1, assemble and weld the pin caps and pin legs to form an internal pin assembly, and then weld the internal pin assembly to the PCBA;

[0013] Step 2: Clean the PCBA, assemble it into a plastic package, and perform plastic injection to form a double-sided plastic package product module.

[0014] Step 3: Grind and cut the plastic-sealed product module as required;

[0015] Step 4, riveting and reflow soldering the external pins of the module processed in step 3;

[0016] Step 5: Apply thermal conductive material on the upper and lower surfaces of the welded module, and apply solder paste on the inner surface of the stop groove where the bottom plate and the shell match, and then assemble the welded module with the shell and the bottom plate in sequence;

[0017] Step 6: Reflow soldering the module assembled through the above steps

[0018] Compared with the prior art, the present invention has the following significant advantages:

[0019] 1) The present invention as a whole has the characteristics of simple plastic packaging process, good heat dissipation effect, small size, convenient installation, good environmental adaptability, high pin strength, high electromagnetic shielding performance, etc., which can significantly improve the reliability of electronic products.

[0020] 2) The shell and the base plate are fixed by solder paste and high-temperature reflow, which further reduces the thermal resistance between the shell and the base plate, thereby significantly improving the heat dissipation capacity of the heat-generating components on the upper surface of the PCBA through the plastic package-shell-base plate path.

[0021] 3) The four right angles of the square at the bottom of the external pin are fixed to the round hole by interference riveting and reflow soldering, ensuring the basic mechanical strength of the product pin.

[0022] 4) The pins of the product module are embedded in the plastic package body in the early stage, polished out in the later stage, and then riveted and welded to lengthen the pins. This overcomes a series of problems caused by the final product pins being directly welded to the PCBA in the early stage to the plastic package mold and process, such as the high requirements for the external dimensions and welding consistency of the pins of each PCBA. In addition, the plastic package mold forms a small gap (generally required to be less than 0.03mm) through precise matching with the pins on the PCB to protect the epoxy glue used in the plastic package process from contaminating the pin surface beyond the plastic package body.

[0023] 5) The shell of the plastic package can effectively isolate the external environment, such as the impact of harsh environments such as high humidity and salt spray on the internal part of the product. It can also significantly improve the electromagnetic shielding performance, thereby improving the reliability of the product.

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of PCBA of the present invention.

[0026] Figure 2 Schematic diagram of the internal pin assembly of the present invention.

[0027] Figure 3 Schematic diagram of the PCBA plastic encapsulation process of the present invention, wherein Figure (a) is an exploded view of the plastic encapsulation process, and Figure (b) is a cross-sectional view of the plastic encapsulation process.

[0028] Figure 4 This is a schematic diagram of the PCBA after plastic packaging of the present invention.

[0029] Figure 5 This is a schematic diagram of the plastic package body of the present invention after grinding / cutting.

[0030] Figure 6 This is a schematic diagram of welding external pins of the product of the present invention.

[0031] Figure 7 This is a schematic diagram of the assembled shell of the product of the present invention.

[0032] Figure 8 This is the final cross-sectional view of the product of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0034] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0035] In one embodiment, a double-sided packaging structure of an electronic product is provided, comprising a PCBA 1, a base plate 10, a shell 9, a plastic package body 6, internal pin components 2 / 3 and external pins 7 / 8; wherein a power tube, a chip and a magnetic core that need to be cooled are fixed on the PCBA 1, and the internal pin components 2 / 3 are welded on the PCBA; during the plastic packaging process, the PCBA is placed in the cavity of a plastic packaging mold 4 / 5, and the upper and lower surfaces of the PCBA are wrapped by the plastic package body 6; the product module after plastic packaging can be cut into a desired shape and polished to reveal the internal pin components, the internal pin components are riveted to the external pins, and reflow soldered; the product module after plastic packaging is installed in the shell, and a base plate is assembled on the lower surface of the shell to fix the product module.

[0036] Combination Figure 2 The internal pin assembly 2 includes a pin cap 2.1 and a pin leg 2.2. A groove is provided at the top middle position of the pin leg 2.2. After the pin cap 2.1 is welded, a sealed cavity is formed between the two, which is convenient for welding the external pins 7 / 8 later. The welded internal pin assembly 2 is welded to the PCBA1. Figure 1 shown.

[0037] Here, the pin cap 2.1 and the pin leg 2.2 are fixed by soldering.

[0038] Here, according to the actual requirements of the external pins of the product, internal pins with different outer diameters and quantities can be set accordingly.

[0039] Combination Figure 3The plastic encapsulation body includes a plastic encapsulation lower mold 4 and a plastic encapsulation upper mold 5 arranged from bottom to top. The PCBA 1 welded with the internal pin components is placed in the cavity of the plastic encapsulation lower mold 4. The plastic encapsulation upper mold 5 and the plastic encapsulation lower mold 4 are molded together to fix the PCBA 1 welded with the internal pin components; a glue inlet is provided on the plastic encapsulation upper mold, and a glue inlet flow channel is provided in the plastic encapsulation upper mold 5 and the plastic encapsulation lower mold 4. The upper and lower sides of the PCBA are plastic encapsulated simultaneously through the glue inlet and the glue inlet flow channel to form a plastic encapsulated product module such as Figure 4 As shown. Grind the plastic-encapsulated product module as required, reveal the magnetic core and internal pin legs 2.2 / 3.2 on the module, and use a cutting machine to cut the polished product into the required shape. For example, cut the polished module into Figure 4 Cut in the AA, BB, CC, and DD directions to leave the final plastic package shape of the PCBA, such as Figure 5 shown.

[0040] like Figure 6 As shown, connect external pins 7 / 8 to Figure 5 The plastic package assembly shown is welded. In order to ensure the welding strength, the bottom of the external pin 7 / 8 is square, and the middle groove on the top of the internal pin assembly pin leg 2.2 / 3.2 is round. The four right angles of the square and the round hole are fixed by interference riveting and reflow soldering, ensuring the basic mechanical strength of the product pin.

[0041] like Figure 7 , Figure 8 As shown, in Figure 6 The upper surface of the component shown is coated with thermal grease or thermal adhesive 11, and then placed in the cavity of the shell 9; then the lower surface of the component is coated with thermal grease or thermal adhesive 11, and solder paste 12 is coated in the stop groove where the bottom plate 10 and the shell 9 match, and then the bottom plate 10 is assembled on the lower surface of the shell 9. Finally, the assembled module is reflowed, and the shell 9 and the bottom plate 10 are welded together.

[0042] Here, the base plate and the shell are made of metal with high thermal conductivity. The shell can effectively isolate the external environment, such as the impact of harsh environments such as high humidity and salt spray on the internal parts of the product, and can also significantly improve the electromagnetic shielding performance, thereby improving the reliability of the product.

[0043] The assembly method of the packaging structure includes the following steps:

[0044] Step 1, assemble and weld the pin caps and pin legs to form an internal pin assembly, and then weld the internal pin assembly to the PCBA;

[0045] Step 2: Clean the PCBA, assemble it into a plastic package, and perform plastic injection to form a double-sided plastic package product module.

[0046] Step 3: Grind and cut the plastic-sealed product module as required;

[0047] Step 4, riveting and reflow soldering the external pins of the module processed in step 3;

[0048] Step 5: Apply thermal conductive material on the upper and lower surfaces of the welded module, and apply solder paste on the inner surface of the stop groove where the bottom plate and the shell match, and then assemble the welded module with the shell and the bottom plate in sequence;

[0049] Step 6, reflow soldering the module assembled through the above steps.

[0050] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A double-sided packaging structure for an electronic product, characterized in that: It includes PCBA, base plate, shell, plastic package, internal pin assembly and external pin; wherein power tubes, chips and magnetic cores that need heat dissipation are fixed on PCBA, and internal pin assembly is welded on PCBA; PCBA wraps the upper and lower surfaces through plastic package by plastic package process; the product module after plastic package is cut and polished to form the required shape and the internal pin assembly is exposed, the internal pin assembly is riveted to the external pin, and reflow soldering is performed; the product module after plastic package is installed in the shell, and the bottom plate is assembled on the lower surface of the shell to fix the product module; the internal pin assembly includes a pin cap and a pin leg, and a groove is provided at the middle position of the top of the pin leg. After the pin cap is welded, a sealed cavity is formed between the two, which is convenient for the later welding of the external pin; the bottom of the external pin is square, and the groove at the top of the pin leg is round; the four right angles of the square at the bottom of the external pin are fixed to the round hole by interference riveting and reflow soldering; The assembly method of the packaging structure includes the following steps: Step 1, assemble and weld the pin caps and pin legs to form an internal pin assembly, and then weld the internal pin assembly to the PCBA; Step 2, cleaning the PCBA, then assembling it into a plastic package and performing plastic injection to form a double-sided plastic package product module; Step 3: Grind and cut the plastic-sealed product module as required; Step 4, riveting and reflow soldering the external pins of the module processed in step 3; Step 5: Apply thermal conductive material on the upper and lower surfaces of the welded module, and apply solder paste on the inner surface of the stop groove where the bottom plate and the shell match, and then assemble the welded module with the shell and the bottom plate in sequence; Step 6, reflow soldering the module assembled through the above steps.

2. The double-sided packaging structure of an electronic product according to claim 1, characterized in that: The plastic encapsulation body includes a lower plastic encapsulation mold and an upper plastic encapsulation mold arranged from bottom to top. The PCBA welded with an internal pin assembly is placed in the cavity of the lower plastic encapsulation mold. The upper plastic encapsulation mold and the lower plastic encapsulation mold are molded together to press and fix the PCBA. A glue inlet is provided on the upper plastic encapsulation mold, and glue inlet channels are provided in the upper plastic encapsulation mold and the lower plastic encapsulation mold. The upper and lower sides of the PCBA are plastic encapsulated simultaneously through the glue inlet and the glue inlet channel to form a plastic encapsulated product module.

3. The double-sided packaging structure of the electronic product according to claim 1, characterized in that: After the product module is plastic-sealed, the upper and lower surfaces are coated with thermal conductive materials and then contact the shell and the bottom plate.

4. The double-sided packaging structure of the electronic product according to claim 3, characterized in that: The heat-conducting material is heat-conducting silicone grease or heat-conducting glue.

5. The double-sided packaging structure of an electronic product according to claim 1, characterized in that: The shell and the bottom plate are fixed by solder paste and high-temperature reflow.

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