A semiconductor package structure with a heat sink in a plastic encapsulation

Abstract

This utility model discloses a semiconductor packaging structure with a heat sink in a molded enclosure, including a frame body and a packaging module disposed on the frame body. The packaging module includes at least a molded enclosure carrying a heat sink, a chip, and bonding wires placed within the molded enclosure. The chip is mounted on the upper surface of the frame body, and the bonding wires electrically connect the chip and the frame body. The heat sink is disposed at the bottom of the molded enclosure, with several grooves formed on its upper surface and embedded within the molded enclosure, while its lower surface is exposed to the air outside the bottom of the molded enclosure. Compared with traditional molded enclosures containing only molding compound, this packaging structure provides an additional effective heat dissipation path by placing a heat sink on the surface of the molded enclosure, thereby improving the heat dissipation performance of the packaging structure. Furthermore, this packaging structure is simple in form, easy to manufacture, and low in cost, making it highly suitable for large-scale industrial production applications.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor packaging technology, specifically to a semiconductor packaging structure with a heat sink in a plastic encapsulation. Background Technology

[0002] Molding technology is a key technology in semiconductor packaging processes, primarily used to protect semiconductor chips from external environmental factors (such as moisture, dust, and chemicals) and provide electrical insulation. Epoxy resin is the most commonly used molding material, widely adopted due to its excellent electrical insulation properties, mechanical strength, and relatively low cost. To meet different application requirements, fillers (such as silica powder) are sometimes added to the substrate to improve thermal expansion coefficient matching, increase thermal conductivity, and reduce water absorption.

[0003] Traditional fillerless molding compounds primarily rely on epoxy resin to fill the chip and its bonding wires to achieve device protection and insulation. However, this method has several significant technical limitations:

[0004] First, given the relatively low thermal conductivity of epoxy resin, it cannot effectively conduct and dissipate the heat generated by the chip during operation, leading to an increase in the internal temperature of the device, which affects electrical performance and may shorten the device's lifespan. Second, due to the lack of an effective heat dissipation mechanism, relying solely on epoxy resin is insufficient to meet the high-efficiency heat dissipation requirements of high-power-density devices (such as IGBT modules and power modules), limiting the performance of such devices in high-performance applications. Finally, epoxy resin exhibits certain shortcomings in terms of environmental adaptability: the difference in its coefficient of thermal expansion under extreme temperature changes may lead to increased internal stress in the package, thereby affecting the long-term stability and reliability of the package structure; furthermore, in high-temperature and high-humidity environments, the protective performance of epoxy resin may not be sufficient to completely prevent moisture intrusion, further threatening the reliable operation of the device. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide a semiconductor package structure with a heat sink in the molded body, which provides an additional heat dissipation path by setting a heat sink on the molded body, thereby improving the heat dissipation performance of the package structure.

[0006] To achieve the above objectives, the present invention employs the following technical means:

[0007] This utility model proposes a semiconductor packaging structure with a heat sink in a plastic encapsulation, including a frame body and a packaging module disposed on the frame body. The packaging module includes at least a plastic encapsulation housing carrying a heat sink and a chip and bonding wires disposed within the plastic encapsulation housing.

[0008] The chip is mounted on the upper surface of the frame body, and the bonding wire is electrically connected to the chip and the frame body; the heat sink is disposed at the bottom of the molding compound, with several grooves on its upper surface and embedded in the molding compound, and its lower surface exposed to the air outside the bottom of the molding compound.

[0009] Preferably, the heat sink is made of aluminum.

[0010] Preferably, the lower surface of the heat sink is at the same level as the bottom of the molding compound.

[0011] Preferably, the groove is linear, including a concave portion and a convex portion, wherein the width of the concave portion is twice the width of the convex portion.

[0012] Preferably, the thickness of the heat sink is 1.2 cm, the width of the recess is 0.4 cm, the width of the convex part is 0.2 cm, and the height of the convex part relative to the recess is 0.2 cm.

[0013] Preferably, the two sides of the encapsulated body are recessed inward to form a recessed portion, thereby increasing the contact area between the surface of the encapsulated body and the outside air.

[0014] Preferably, the chip includes an IGBT chip, a power management chip, and an LED chip.

[0015] Preferably, a foolproof notch is formed by cutting inward along one of the sides of the frame body along its length.

[0016] Preferably, the encapsulation module is located in the middle of the frame body, and the frame body has a through hole on each side of the encapsulation module along its length; the frame body has a downwardly recessed solder reservoir on the side of each of the two through holes away from the encapsulation module.

[0017] Preferably, positioning holes are provided at the four corners of the frame body, and welding bosses are provided at both ends of the frame body along the length direction and between the two positioning holes.

[0018] The beneficial effects of this utility model are as follows:

[0019] (1) The present invention provides a heat sink on the plastic encapsulation of the packaging structure. One side of the heat sink is embedded in the plastic encapsulation, and the other side is exposed to the air. Since the heat sink is made of a material with better thermal conductivity, such as aluminum, compared with the traditional plastic encapsulation that mainly relies on epoxy resin to fill the chip and its bonding wires, the heat generated by the chip can be dissipated into the air more quickly through the heat sink. This is beneficial to improving the heat dissipation performance of the packaging structure, meeting the requirements of high power density devices (such as IGBT modules, power modules, etc.) for efficient heat dissipation, helping to improve the performance of such devices in high-performance applications, and extending the service life of the devices.

[0020] (2) The present invention designs the side of the heat sink embedded in the plastic encapsulation as a straight groove structure, which increases the contact area between the heat sink and the plastic encapsulation, and can further improve the heat dissipation performance of the encapsulation structure.

[0021] (3) The present invention designs the two sides of the encapsulation body as an inwardly concave structure, which increases the contact area between the surface of the encapsulation body and the outside air compared with the cuboid structure in the prior art, and further improves the heat dissipation performance of the encapsulation structure.

[0022] (4) The semiconductor packaging structure of this utility model is simple, easy to manufacture, and low in cost, which is very beneficial to large-scale industrial production applications. Attached Figure Description

[0023] Figure 1 This is a front view of the semiconductor packaging structure according to an embodiment of the present invention;

[0024] Figure 2 This is a reverse view of the semiconductor packaging structure according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the position of the heat sink in the plastic package, shown from a frontal view, according to an embodiment of the present invention.

[0026] Figure 4 This is a front view of the heat sink according to an embodiment of the present utility model;

[0027] Figure 5 This is a side view of the heat sink according to an embodiment of the present utility model;

[0028] Figure 6 This is a process flow diagram for fabricating the semiconductor packaging structure according to an embodiment of the present invention.

[0029] In the figure: 1. Frame body; 2. Packaging module; 3. Molded body; 31. Recessed part; 32. Snap-on slot; 4. Foolproof notch; 5. Through hole; 6. Solder reservoir; 61. Solder block; 7. Positioning hole; 8. Boss; 9. Heat sink; 91. Groove; 9101. Protrusion; 9102. Recess. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0031] In the description of this utility model, it should be understood that the terms "upper," "lower," "front," "rear," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0032] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to the internal connection of two components; they can refer to a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0033] See Figures 1-5 This embodiment of a semiconductor package structure with a heat sink in a molded enclosure includes a frame body 1 and a packaging module 2 disposed on the frame body 1. The frame body 1 is made of copper plate and has strong structural strength, undertaking the functions of heat dissipation, conductivity, and support. The packaging module 2 includes at least a molded enclosure 3 carrying a heat sink 9, a chip placed inside the molded enclosure 3, and bonding wires. The chip is mounted on the upper surface of the frame body 1, and the bonding wires electrically connect the chip and the frame body 1. The heat sink 9 is disposed at the bottom of the molded enclosure 3, and its upper surface has several grooves 91. The grooves 91 are embedded in the molded enclosure 3, and its lower surface is exposed to the air outside the bottom of the molded enclosure 3. In this embodiment, the types of chips include, but are not limited to, IGBT chips, power management chips, and LED chips. These chips are used in high power density devices and have high requirements for efficient heat dissipation.

[0034] Furthermore, the heat sink 9 is preferably an aluminum sheet with a thermal conductivity of 237 W / m·K and low cost. The aluminum sheet is rectangular in shape and its size is adapted to the dimensions of the bottom of the molding die. During molding, the heat sink 9 is placed at the bottom of the die, and then epoxy resin or other molding materials are injected into the die to form the molding compound 3, achieving electrical insulation and chip protection. At the same time, the bottom surface of the molded heat sink 9 is exposed to the air, and the bottom surface of the heat sink 9 is at the same level as the bottom of the molding compound 3. Since the heat sink 9 is made of aluminum with good thermal conductivity, the heat generated by the chip can be quickly dissipated into the air through the heat sink 9 after adopting the above structure, effectively improving the heat dissipation performance of the package structure.

[0035] It is worth noting that in this embodiment, the upper surface of the heat sink 9 embedded in the molding compound 3 is configured as a groove 91, which can greatly increase the surface area of ​​contact between the heat sink 9 and the molding compound 3, further enhancing the heat dissipation efficiency of the molding compound 3. Figure 4 and Figure 5 As shown, preferably, the groove 91 is linear in shape, including a recess 9102 and a protrusion 9101, wherein the width of the recess 9102 is twice the width of the protrusion 9101. More preferably, in this embodiment, the thickness of the heat sink 9 is set to 1.2 cm, the width of the recess 9102 is set to 0.4 cm, the width of the protrusion 9101 is set to 0.2 cm, and the height of the protrusion 9101 relative to the recess 9102 is set to 0.2 cm. It should be noted that the groove 91 is oriented towards the molded body 3. In addition to increasing the contact area with the molded body 3, another reason is that if it is oriented towards the outside air, that is, if the side of the heat sink 9 with the groove 91 is placed facing the bottom of the mold during molding, glue will easily overflow during the formation of the molded body 3, affecting the appearance of the molded body 3.

[0036] Furthermore, such as Figure 1 and Figure 2 As shown, positioning holes 7 are provided at the four corners of the frame body 1, and a foolproof notch 4 is cut inward along one of the sides of the frame body 1 along its length. The design of the foolproof notch 4 and the four positioning holes 7 corresponds to the installation position on the client, ensuring zero-error rapid assembly of the packaging structure with the client, improving work efficiency and saving costs. Simultaneously, combined with... Figure 3 As shown, snap-fit ​​grooves 32 are provided at the front and rear ends of the front of the plastic seal 3, which are used to engage with the corresponding structure on the client and play a specified role.

[0037] Furthermore, such as Figures 1-3As shown, the packaging module 2 is located in the middle of the frame body 1. Notably, its molding compound 3 has square recesses 31 on both sides, which increases the contact area between the surface of the molding compound 3 and the outside air, further enhancing its heat dissipation performance. Along the length of the frame body 1, a through hole 5 is provided on both sides of the packaging module 2 near the recesses 31 of the molding compound 3, serving as a channel for the client to assemble the copper strip. Part of the left through hole 5 is covered by the molding compound 3, while a portion of the copper frame is left between the right through hole 5 and the molding compound 3. Because the chip's soldering area on the frame body 1 is located on the right side of the molding compound 3, and copper has a higher thermal conductivity than molding materials such as epoxy resin, reserving a portion of the copper frame nearby makes it easier to improve the heat dissipation performance of the packaging structure, given the relatively concentrated heat in the chip soldering area.

[0038] Furthermore, the frame body 1 has two recessed solder reservoirs 6 on the side of the two through holes 5 away from the packaging module 2, each containing a solder block 61. Simultaneously, bosses 8 are provided at both ends of the frame body 1 along its length, between the two positioning holes 7. Both the solder reservoirs 6 and the bosses 8 are used for soldering during the assembly of the packaging structure and the client, facilitating quick positioning of the soldering area and efficient soldering operations by assembly personnel. It should be understood that the packaging structure is installed on the client in an inverted manner. In this case, the bottom of the plastic package 3 with the heat sink 9 faces upwards, away from the client, allowing the heat sink 9 to be fully exposed to the air, achieving efficient heat dissipation.

[0039] The following further describes the fabrication process of a semiconductor package structure with a heat sink in a plastic encapsulation according to this embodiment. For example... Figure 6 As shown, this embodiment adds heat sink filling, sealing, and film removal steps to the sealing stage of the existing encapsulation process, which includes welding, die bonding, bonding, encapsulation, and post-curing. The specific steps are as follows:

[0040] Step S1: The heat sink 9 is pre-filled into the lower cover of the plastic encapsulation mold. The side of the heat sink 9 with the groove 91 faces upward, and the other flat side is covered with a protective film and faces downward to fit against the lower cover of the encapsulation mold.

[0041] Step S2: Place the frame body 1 containing the chip and bonding wires into the molding die, and then perform injection molding to fill the area around the chip and bonding wires with molding compound to form a molding compound 3. The groove 91 of the heat sink 9 is embedded in the molding compound 3, and the lower surface is exposed to the air.

[0042] Step S3: Remove the protective film from the surface portion of the heat sink 9 exposed to the air to allow it to perform its heat dissipation function effectively.

Claims

1. A semiconductor package structure with a heat sink in a plastic encapsulation, comprising a frame body (1) and a package module (2) disposed on the frame body (1), characterized in that, The packaging module (2) includes at least a plastic package (3) carrying a heat sink (9) and a chip and bonding wires placed within the plastic package (3), wherein, The chip is attached to the upper surface of the frame body (1), and the bonding wire is electrically connected to the chip and the frame body (1); the heat sink (9) is disposed at the bottom of the molding compound (3), and its upper surface has several grooves (91) and is embedded in the molding compound (3), while its lower surface is exposed to the outside air at the bottom of the molding compound (3).

2. The semiconductor packaging structure according to claim 1, characterized in that, The heat sink (9) is made of aluminum.

3. The semiconductor packaging structure according to claim 1, characterized in that, The lower surface of the heat sink (9) is at the same level as the bottom of the encapsulation (3).

4. The semiconductor packaging structure according to claim 1, characterized in that, The groove (91) is linear and includes a recess (9102) and a convex part (9101), wherein the width of the recess (9102) is twice the width of the convex part (9101).

5. The semiconductor packaging structure according to claim 4, characterized in that, The thickness of the heat sink (9) is 1.2 cm, the width of the recess (9102) is 0.4 cm, the width of the protrusion (9101) is 0.2 cm, and the height of the protrusion (9101) relative to the recess (9102) is 0.2 cm.

6. The semiconductor packaging structure according to claim 1, characterized in that, The two sides of the encapsulated body (3) are recessed inward to form a recessed portion (31) to increase the contact area between the surface of the encapsulated body (3) and the outside air.

7. The semiconductor packaging structure according to claim 1, characterized in that, The chip includes an IGBT chip, a power management chip, and an LED chip.

8. The semiconductor packaging structure according to claim 1, characterized in that, The frame body (1) is cut inward along one of its sides in the length direction to form a foolproof notch (4).

9. The semiconductor packaging structure according to claim 1, characterized in that, The encapsulation module (2) is located in the middle of the frame body (1). The frame body (1) has a through hole (5) on each side of the encapsulation module (2) along the length direction. The frame body (1) has a downwardly recessed solder reservoir (6) on the side of the two through holes (5) away from the encapsulation module (2).

10. The semiconductor packaging structure according to claim 1, characterized in that, The frame body (1) is provided with positioning holes (7) at its four corners, and the frame body (1) is provided with bosses (8) for welding at both ends along its length and between the two positioning holes (7).

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