Chip packaging heat sink and preparation method thereof and BGA heat dissipation packaging structure

Abstract

The embodiments of the present invention provide a chip packaging heat sink and a preparation method thereof and a BGA heat dissipation packaging structure, which relate to the field of semiconductor packaging technology. The chip packaging heat sink includes a heat sink body, the heat sink body has a relative fitting surface and a molding surface, and a first groove is provided on the fitting surface, and a first fence is formed on the edge of the first groove, and a second groove is provided on the molding surface, and a second fence is formed on the edge of the second groove. Through the two fence structures, it is possible to avoid the plastic encapsulation material from remaining on the surface of the heat sink body as much as possible, thereby ensuring the heat dissipation performance and neat appearance of the chip packaging heat sink. Compared with the prior art, the chip packaging heat sink and a preparation method thereof and the BGA heat dissipation packaging structure provided by the present invention can prevent the plastic encapsulation material from overflowing onto the surface of the heat sink, avoid the heat sink from having overflowing glue, and ensure the heat dissipation efficiency of the heat sink and the neat appearance of the product.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and in particular to a chip packaging heat sink and a preparation method thereof, and a BGA heat dissipation packaging structure. Background Art

[0002] With the rapid development of the semiconductor industry, the BGA solder ball array package (Ball Grid Array Package) packaging structure is widely used in the semiconductor industry. Generally, the BGA packaging structure is used to achieve heat dissipation by mounting a heat sink, which requires the heat sink to meet the heat dissipation requirements. When setting the heat sink, a heat sink groove is usually designed on the packaging mold. When the plastic package is molded and injected, the top surface of the heat sink contacts the top of the mold and is attached to the plastic package under the drive of the mold.

[0003] If the top surface of the heat sink fails to effectively contact the top of the mold, there will be a gap between the two. When the plastic molding material is injected, it is easy for the plastic molding material to overflow onto the surface of the heat sink. Once there is overflow glue on the top surface of the heat sink, it will directly affect the heat dissipation efficiency of the heat sink and the appearance of the product. Therefore, de-glueing is often required, which directly increases the packaging cost and the risk of damage to the heat sink. Summary of the invention

[0004] The objectives of the present invention include, for example, providing a chip packaging heat sink and its preparation method and a BGA heat dissipation packaging structure, which can prevent the plastic packaging material from overflowing onto the surface of the heat sink, avoid excess glue on the heat sink, and ensure the heat dissipation efficiency of the heat sink and the neat appearance of the product.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] In a first aspect, the present invention provides a chip packaging heat sink, comprising a heat sink body, the heat sink body having a relative fitting surface and a molding surface, the fitting surface being used to fit on a plastic packaging body, and a first groove being provided on the fitting surface, and a first fence being formed at the edge of the first groove, the first fence being arranged around the lower edge of the heat sink body to prevent the plastic packaging material from overflowing during plastic packaging; the molding surface being used to combine with a mold, and a second groove being provided on the molding surface, and a second fence being formed at the edge of the second groove, the second fence being arranged around the upper edge of the heat sink body to prevent the plastic packaging material from crawling onto the molding surface during plastic packaging.

[0007] In an optional embodiment, the depth of the first groove is 1 / 3-1 / 2 of the thickness of the heat sink body; the depth of the second groove is 1 / 3-1 / 2 of the thickness of the heat sink body.

[0008] In an optional embodiment, a first groove is further provided on the bottom wall of the first groove, the first groove is provided on the inner side of the first fence, and is annularly provided on the edge of the first groove, and the first groove is used to increase the contact area between the heat sink body and the plastic packaging body during plastic packaging, and prevent the plastic packaging material from overflowing outward.

[0009] In an optional embodiment, a second groove is further provided on the bottom wall of the second groove. The second groove is provided on the inner side of the second fence and is annularly provided on the edge of the second groove. The second groove is used to store the molding material during molding to prevent the molding material from overflowing to the middle position of the molding surface.

[0010] In an optional embodiment, there are a plurality of first grooves, the plurality of first grooves are arranged in layers around each other, and the widths of the plurality of first grooves are the same; there are a plurality of second grooves, the plurality of second grooves are arranged in layers around each other, and the widths of the plurality of second grooves are the same.

[0011] In an optional embodiment, the thickness of the first groove and the second groove are both 1 / 3-1 / 2 of the thickness of the heat sink.

[0012] In an optional embodiment, the heat sink body is rectangular, and rounded structures are provided at four corners of the heat sink body to increase the separation angle between the heat sink body and the mold.

[0013] In an optional embodiment, the radius of the rounded structure is 2 mm.

[0014] In an optional embodiment, the molded surface is further electroplated to form a metal layer, and the metal layer covers the surface of the heat sink body to prevent the surface of the heat sink body from being oxidized.

[0015] In an optional embodiment, the bonding surface is further coated with a green paint layer or roughened by electroplating to form a nodular layer, so as to improve the bonding force between the bonding surface and the plastic packaging body.

[0016] In a second aspect, the present invention provides a BGA heat dissipation packaging structure, comprising a substrate, a chip, a plastic package and a chip packaging heat sink as described in any of the aforementioned embodiments, wherein the chip is mounted on the substrate, the plastic package is arranged on the substrate and covers the outside of the chip, and the bonding surface is mounted on the plastic package.

[0017] In a third aspect, the present invention provides a method for preparing a chip packaging heat sink, which is used to prepare the aforementioned chip packaging heat sink, and the method comprises:

[0018] include:

[0019] Providing a heat sink body, the heat sink body having a mating surface and a molding surface opposite to each other;

[0020] Forming a first groove on the bonding surface by laser grooving or punching process, and forming a first fence on the edge of the first groove;

[0021] Forming a second groove on the molded surface by laser grooving or stamping, and forming a second fence on the edge of the second groove;

[0022] The first fence is arranged around the lower edge of the heat sink body to prevent the molding compound from overflowing during molding, and the second fence is arranged around the upper edge of the heat sink body to prevent the molding compound from crawling onto the molding surface during molding.

[0023] The beneficial effects of the embodiments of the present invention include, for example:

[0024] The chip encapsulation heat sink and its preparation method and BGA heat dissipation packaging structure provided by the present invention form a first groove and a second groove by slotting on the upper and lower sides of the heat sink body respectively, and form a first fence at the edge of the first groove and a second fence at the edge of the second groove. When plastic sealing is actually performed, the first fence is close to the plastic sealing body to prevent the plastic sealing material from overflowing during plastic sealing, and the second fence is used to prevent the plastic sealing material from crawling to the molding surface. Through the two fence structures, the plastic sealing material can be avoided as much as possible from remaining on the surface of the heat sink body, thereby ensuring the heat dissipation performance and neat appearance of the chip encapsulation heat sink. Compared with the prior art, the chip encapsulation heat sink and its preparation method and BGA heat dissipation packaging structure provided by the present invention can prevent the plastic sealing material from overflowing to the surface of the heat sink, avoid the heat sink from having overflow glue, and ensure the heat dissipation efficiency of the heat sink and the neat appearance of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic structural diagram of a chip package heat sink provided by a first embodiment of the present invention at a first viewing angle;

[0027] Figure 2 A schematic structural diagram of a chip package heat sink provided by the first embodiment of the present invention at a second viewing angle;

[0028] Figure 3A schematic structural diagram of the chip package heat sink provided by the first embodiment of the present invention at a third viewing angle;

[0029] Figure 4 for Figure 3 A partial enlarged schematic diagram of middle Ⅳ;

[0030] Figure 5 for Figure 3 A partial enlarged schematic diagram of middle V;

[0031] Figure 6 A schematic structural diagram of a chip packaging heat sink provided by a second embodiment of the present invention at a first viewing angle;

[0032] Figure 7 A schematic structural diagram of a chip package heat sink provided by a second embodiment of the present invention at a second viewing angle;

[0033] Figure 8 A schematic diagram of a partial structure of a chip packaging heat sink provided in a second embodiment of the present invention;

[0034] Fig. 9 A schematic diagram of a BGA heat dissipation packaging structure provided in a fourth embodiment of the present invention.

[0035] Icons: 100-chip package heat sink; 110-heat sink body; 111-rounded corner structure; 130-fitting surface; 131-green paint layer; 150-molded surface; 151-metal layer; 170-first groove; 171-first fence; 173-first groove; 190-second groove; 191-second fence; 193-second groove; 200-BGA heat dissipation packaging structure; 210-chip; 230-substrate; 250-plastic package body. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0039] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0040] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0041] As disclosed in the background technology, the existing heat dissipation packaging structure usually needs to be mounted with a heat sink for heat dissipation. When performing plastic packaging, it is necessary to design a heat sink groove on the packaging mold and install the heat sink. When the plastic packaging body is injection molded, the top surface of the heat sink contacts the top of the mold and is attached to the plastic packaging material under the drive of the mold.

[0042] In this case, since the plastic encapsulation material is in an unsolidified state and has strong fluidity under pressure, if the top surface of the heat sink fails to effectively contact the top of the mold, a small gap will be caused between the mold and the heat sink. When the plastic encapsulation material is injected, the plastic encapsulation material may climb to the top surface of the heat sink along the side wall of the heat sink. Once there is overflow glue on the top surface of the heat sink. On the one hand, the overflow glue reduces the effective heat dissipation area of ​​the heat sink, which may affect the heat dissipation efficiency of the heat sink. On the other hand, after the packaging is completed, the overflow glue is exposed to the outside, which will affect the neatness of the product's appearance. Therefore, the prior art often requires degumming, which directly increases the packaging cost and the risk of damage to the heat sink.

[0043] In order to solve the above problems, the present invention provides a novel chip packaging heat sink and its preparation method and BGA heat dissipation packaging structure. It should be noted that the features in the embodiments of the present invention can be combined with each other without conflict.

[0044] First embodiment

[0045] See also Figures 1 to 5 The present embodiment provides a chip packaging heat sink 100, which is suitable for a BGA heat dissipation packaging structure 200, and can prevent the plastic packaging material from overflowing onto the surface of the heat sink, avoid excess glue on the heat sink, and ensure the heat dissipation efficiency of the heat sink and the neat appearance of the product.

[0046] The chip package heat sink 100 provided in this embodiment includes a heat sink body 110. The heat sink body 110 has a bonding surface 130 and a molding surface 150 opposite to each other. The bonding surface 130 is used to bond to the plastic package body 250 (see Fig. 9 ), and a first groove 170 is provided on the fitting surface 130, and a first fence 171 is formed at the edge of the first groove 170, the first fence 171 is arranged around the lower edge of the heat sink body 110, and is used to prevent the sealing material from overflowing during sealing; the molding surface 150 is used to combine with the mold, and a second groove 190 is provided on the molding surface 150, and a second fence 191 is formed at the edge of the second groove 190, the second fence 191 is arranged around the upper edge of the heat sink body 110, and is used to prevent the sealing material from crawling to the molding surface 150 during sealing.

[0047] In this embodiment, a cutting path is also provided on the heat sink body 110. The cutting path is a trajectory line when the product is cut after the plastic packaging is completed, that is, the product is cut along the cutting path. The cutting path here is located on the inner side of the first fence 171 and the second fence 191, that is, after the cutting is completed, the first fence 171 and the second fence 191 can be cut off to ensure the miniaturization of the package size. It should be noted that the cutting path here is a virtual trace and is not marked on the heat sink body 110. It is set close to the first fence 171 and the second fence 191 and is ring-shaped, so that the BGA heat dissipation packaging structure 200 formed after cutting can completely remove the first fence 171 and the second fence 191, and avoid waste of heat sink body 110 material.

[0048] In this embodiment, the depth of the first groove 170 is 1 / 3-1 / 2 of the thickness of the heat sink body 110; the depth of the second groove 190 is 1 / 3-1 / 2 of the thickness of the heat sink body 110. Specifically, the first groove 170 extends to the edge of the heat sink body 110, and forms a first fence 171 at the edge of the fitting surface 130 of the heat sink body 110, and the second groove 190 extends to the edge of the heat sink body 110, and forms a second fence 191 at the edge of the molded surface 150 of the heat sink body 110. The height of the first fence 171 refers to the depth of the first groove 170, and the height of the second fence 191 refers to the depth of the second groove 190. Preferably, the thickness of the heat sink body 110 is 0.13 mm, and the thickness of the first groove 170 and the second groove 190 are both 0.05 mm, that is, the height of the first fence 171 and the height of the second fence 191 are both 0.05 mm.

[0049] It should be noted that, in this embodiment, the overlapping area of ​​the first groove 170 and the second groove 190 is the effective heat dissipation area of ​​the chip package heat sink 100, and the heat dissipation function is achieved through this area. This also ensures that the first fence 171 and the second fence 191 can be removed from the chip package heat sink 100 after cutting to ensure the consistency of the product.

[0050] In this embodiment, the first fence 171 and the second fence 191 are symmetrically arranged on the upper and lower sides of the heat sink body 110. When the plastic packaging is actually performed, the second fence 191 can also match the mold. For example, a protrusion structure that matches the second groove 190 is formed on the mold, so that the heat sink body 110 and the mold fit better, thereby reducing the gap between the two. The first fence 171 is close to the plastic packaging body 250 to prevent the plastic packaging material from overflowing during the plastic packaging, and the second fence 191 is used to prevent the plastic packaging material from crawling sideways to the molding surface 150. Through the two fence structures, the plastic packaging material can be avoided as much as possible from remaining on the surface of the heat sink body 110, thereby ensuring the heat dissipation performance and neat appearance of the chip packaging heat sink 100.

[0051] In this embodiment, the heat sink body 110 is rectangular, and its aspect ratio can be set according to actual packaging requirements. For example, a heat sink body 110 with a specification of 240 mm×76 mm is used. This specification size should be larger than the size of the final product to ensure that the first fence 171 and the second fence 191 can be cut off after cutting. Of course, the specification size of the heat sink body 110 and the specific heights of the first fence 171 and the second fence 191 are only examples and do not play any limiting role.

[0052] In this embodiment, fillet structures 111 are provided at the top corners of the heat sink body 110 to improve the separation angle between the heat sink body 110 and the mold. Specifically, R chamfers are designed around the heat sink body 110, and the chamfers can improve the separation angle between the heat sink body 110 and the mold groove, so that the mold can be better separated after the chip package heat sink 100 is pressed.

[0053] In this embodiment, the radius of the fillet structure 111 is 2 mm. That is, the fillets at the four corners of the heat sink body 110 are arcs with a radius of 2 mm. Of course, the radius of the fillet structure 111 here is only an example and does not play any limiting role.

[0054] In this embodiment, the molded surface 150 is also electroplated to form a metal layer 151. Specifically, the heat sink body 110 adopts a copper foil structure, and the metal layer 151 covers the surface of the heat sink body 110 to prevent the surface of the heat sink body 110 from being oxidized. The metal layer 151 is a multi-layer structure, such as a chromium-nickel composite layer, that is, the outer layer is a chromium layer, and the inner layer is a nickel layer. The chromium material can improve the wear resistance and oxidation resistance of the surface, and the nickel layer can improve the bonding force with the copper foil surface to ensure the stability of the structure. Of course, the metal layer 151 here can also be made of other types of pure metal materials or composite metal materials. This is just an example and does not play any limiting role.

[0055] It should be noted that, in this embodiment, the step of forming the metal layer 151 by electroplating can be performed before forming the second groove 190, that is, after the metal layer 151 is formed by electroplating, the second groove 190 is formed by laser grooving or stamping. Of course, the electroplating operation can also be performed after the second groove 190 is formed, in which case the surface of the heat sink body 110 can be covered with the metal layer 151, thereby ensuring its anti-oxidation effect.

[0056] In this embodiment, the bonding surface 130 is also coated with a green paint layer 131 to improve the bonding force between the bonding surface 130 and the plastic package 250. Specifically, green paint is applied on the surface of the copper foil structure by printing, and the green paint material can improve the bonding force between the plastic package 250 and the copper foil. It should be noted that the green paint layer 131 here is solder resist ink, which is applied by printing.

[0057] In other preferred embodiments of the present invention, the bonding surface 130 may not be printed with green paint, but instead adopts an electroplating roughening process to form a nodular layer on the bonding surface 130. Specifically, the nodular layer is distributed in a honeycomb shape, which can also improve the bonding force between the plastic package 250 and the copper foil surface. Of course, the electroplating roughening process here can also directly form a surface roughness structure on the bonding surface 130, such as directly opening strip grooves, to increase the surface roughness of the bonding surface 130, thereby improving the bonding force between it and the plastic package 250.

[0058] It should be noted that in this embodiment, the green paint layer 131 or the tumor layer at least covers the bottom wall surface of the first groove 170 , thereby enhancing the bonding force between the effective heat dissipation area of ​​the heat sink body 110 and the plastic package body 250 .

[0059] In summary, the chip encapsulation heat sink 100 provided in this embodiment can be designed in accordance with the size of the plastic encapsulation body 250 by designing the structure of the heat sink body 110, and rounded corner structures 111 are designed around to facilitate the wind force between the mold and the heat sink body 110. At the same time, a first fence 171 is formed after the fitting surface 130 is grooved, which can effectively prevent the plastic encapsulation material from overflowing outward, and a second fence 191 is formed after the molding surface 150 is grooved, which can effectively prevent the plastic encapsulation material from crawling sideways to the top surface of the heat sink body 110 during the plastic encapsulation process, thereby solving the problem of surface glue overflow. Through the two fence structures, the plastic encapsulation material can be avoided as much as possible from remaining on the surface of the heat sink body 110, thereby ensuring the heat dissipation performance and neat appearance of the chip encapsulation heat sink 100.

[0060] Second embodiment

[0061] See also Figures 6 to 8 The chip package heat sink 100 provided in this embodiment has the same basic structure, principle and technical effect as those of the first embodiment. For the sake of brief description, the parts not mentioned in this embodiment can refer to the corresponding contents in the first embodiment. The difference between this embodiment and the first embodiment is that a groove structure is added.

[0062] The chip packaging heat sink 100 includes a heat sink body 110, which has a relative fitting surface 130 and a molding surface 150. The fitting surface 130 is used to fit on the plastic packaging body 250, and a first groove 170 is provided on the fitting surface 130, and a first fence 171 is formed at the edge of the first groove 170. The first fence 171 is surrounded by the lower edge of the heat sink body 110 to prevent the plastic packaging material from overflowing during plastic packaging; the molding surface 150 is used to combine with the mold, and a second groove 190 is provided on the molding surface 150, and a second fence 191 is formed at the edge of the second groove 190. The second fence 191 is surrounded by the upper edge of the heat sink body 110 to prevent the plastic packaging material from crawling to the molding surface 150 during plastic packaging.

[0063] In this embodiment, a first groove 173 is further provided on the bottom wall of the first groove 170. The first groove 173 is provided on the inner side of the first fence 171 and is provided in an annular shape at the edge of the first groove 170. The first groove 173 is used to increase the contact area between the heat sink body 110 and the plastic packaging body 250 during plastic packaging and prevent the plastic packaging material from overflowing. Specifically, the first groove 173 can overlap with the cutting path, so that the first groove 173 can be cut directly during cutting.

[0064] It should be noted that the first groove 173 in this embodiment has two main functions. The first is to improve the bonding force between the molding compound and the heat sink body 110 during molding. The second is to store the molding compound to prevent a large amount of molding compound from overflowing and causing the molding compound to creep sideways.

[0065] In this embodiment, a second groove 193 is further provided on the bottom wall of the second groove 190. The second groove 193 is provided on the inner side of the second fence 191 and is provided in an annular shape at the edge of the second groove 190. The second groove 193 is used to store the molding material during molding to prevent the molding material from overflowing to the middle position of the molding surface 150. Specifically, the second groove 193 is symmetrical or misaligned with the first groove 173.

[0066] It should be noted that, in this embodiment, the second groove 193 mainly plays the role of storing the plastic molding compound, and its main role is preventive. When there is too much plastic molding compound and causes it to creep sideways to the molding surface 150, it can play the role of storing the plastic molding compound and prevent the plastic molding compound from further flowing toward the center of the molding surface 150.

[0067] In this embodiment, the depth of the first groove 173 and the second groove 193 can be determined according to actual needs and the thickness of the heat sink body 110, wherein when the first groove 173 and the second groove 193 are distributed on the fitting surface 130 and the mold pressing surface 150 in a completely symmetrical manner, the sum of the thickness of the first groove 173 and the second groove 193 should be less than the distance between the bottom wall of the first groove 170 and the bottom wall of the second groove 190, so as to avoid the groove from penetrating the heat sink body 110, for example, when laser grooving is used, the groove depth needs to be precisely controlled. When the first groove 173 and the second groove 193 are distributed on both sides of the heat sink body 110 in a staggered distribution manner, the single thickness of the first groove 173 and the second groove 193 should be less than the distance between the bottom wall of the first groove 170 and the bottom wall of the second groove 190, for example, when the groove is formed by stamping, the depth of the groove needs to be controlled.

[0068] It should be noted that when the first groove 173 and the second groove 193 are completely symmetrically distributed, the cutting path can be overlapped with the first groove 173 and the second groove 193 at the same time, which is convenient for cutting smaller thicknesses during cutting, thereby reducing the wear of the cutter and reducing the pressure required for cutting. When the first groove 173 and the second groove 193 are staggered, the first groove 173 or the second groove 193 can be overlapped with the cutting path, and the single body depth of the first groove 173 or the second groove 193 is deeper than when it is symmetrically distributed, so that more plastic packaging materials can be stored, further preventing glue overflow.

[0069] In this embodiment, there may be a plurality of first grooves 173, and the plurality of first grooves 173 are arranged in layers, and the widths of the plurality of first grooves 173 are the same. There may also be a plurality of second grooves 193, and the plurality of second grooves 193 are arranged in layers, and the widths of the plurality of second grooves 193 are the same. Specifically, when there are a plurality of first grooves 173 and a plurality of second grooves 193, the plurality of first grooves 173 are arranged at intervals, and the plurality of second grooves 193 are arranged at intervals, and the plurality of first grooves 173 and the plurality of second grooves 193 may correspond to each other one by one, or may be arranged in a staggered manner, and the specific distribution method thereof is again not specifically limited.

[0070] It should be noted that in this embodiment, the first fence 171 and the second fence 191 may also be multiple, and the multiple first fences 171 and the multiple first grooves 173 are staggered and repeatedly arranged, and the multiple second fences 191 and the multiple second grooves 193 are staggered and repeatedly arranged. For details, please refer to Figure 8 , This is merely an exemplary description, and the specific number and arrangement of the first fence 171, the second fence 191, the first groove 173 and the second groove 193 are not limited here.

[0071] In summary, the chip package heat sink 100 provided in this embodiment can improve the bonding force between the heat sink body 110 and the plastic package body 250 by adding the first groove 173 and the second groove 193, and prevent the plastic package material from overflowing and causing the plastic package material to creep sideways, and further avoid the plastic package material creeping sideways to the molded surface 150 and causing the glue overflow phenomenon.

[0072] Third embodiment

[0073] This embodiment provides a method for preparing a chip package heat sink 100, which is used to prepare the chip package heat sink 100 provided in the first embodiment or the second embodiment. The method includes:

[0074] S1: Provide a heat sink body 110.

[0075] Specifically, the heat sink body 110 has a relative fitting surface 130 and a molding surface 150, wherein the fitting surface 130 is used to fit on the plastic package body 250, and the molding surface 150 is used to combine with the mold. Preferably, a copper foil can be provided as a raw material. The surface of the copper foil is electroplated to form a metal layer 151 by electroplating to prevent oxidation of the surface of the copper foil. The material of the metal layer 151 can be an outer layer of chromium and an inner layer of nickel, wherein the chromium material improves the wear resistance and zinc oxide resistance of the heat sink body 110, and the nickel layer can improve the bonding strength between the copper foil and the copper foil.

[0076] After the electroplating is completed, green paint can be applied to the other side of the copper foil by printing, wherein the green paint material can enhance the bonding strength between the plastic package 250 and the copper foil. Alternatively, the green paint layer 131 can be omitted and an electroplating roughening process can be used to form a honeycomb-shaped nodular layer on the back of the copper foil, which can also enhance the bonding strength between the plastic package 250 and the copper foil.

[0077] S2: forming a first groove 170 on the bonding surface 130 by laser grooving or punching process, and forming a first fence 171 at the edge of the first groove 170 .

[0078] Specifically, the first groove 170 can be formed by grooved on the side painted with green paint through a laser groove process or a stamping process, and the first groove 170 extends to the edge of the heat sink body 110 , thereby forming a first fence 171 at the edge of the first groove 170 .

[0079] S3: forming a second groove 190 on the bonding surface 130 by laser grooving or punching process, and forming a second fence 191 at the edge of the second groove 190 .

[0080] Specifically, the second groove 190 can be formed by grooved on one side of the electroplated metal layer 151 through a laser groove process or a stamping process, and the second groove 190 extends to the edge of the heat sink body 110 , thereby forming a second fence 191 at the edge of the second groove 190 .

[0081] It should be noted that the step of electroplating the metal layer 151 and the grooving step S3 can be interchanged, that is, the heat sink body 110 formed does not have the metal layer 151. After the second groove 190 is grooved in step S3, the electroplating process is performed to form the metal layer 151, which can better ensure that the metal layer 151 completely covers the surface of the heat sink body 110.

[0082] In this embodiment, the first fence 171 is arranged around the lower edge of the heat sink body 110 to prevent the molding compound from overflowing during molding, and the second fence 191 is arranged around the upper edge of the heat sink body 110 to prevent the molding compound from crawling onto the molding surface 150 during molding.

[0083] After the groove cutting process is completed, the heat sink body 110 can be separated. The size of the separated heat sink body 110 can be designed according to the size of the plastic package body 250 .

[0084] It should be noted that when preparing the chip packaging heat sink 100 provided in the second embodiment, after executing step S2, a first groove 173 can be formed on the bottom wall of the first groove 170 by laser grooving or stamping process; after executing step S3, a second groove 193 can be formed on the bottom wall of the second groove 190 by laser grooving or stamping process.

[0085] The preparation method of the chip packaging heat sink 100 provided by the present invention forms a first groove 170 and a second groove 190 by respectively grooving on the upper and lower sides of the heat sink body 110, and forms a first fence 171 at the edge of the first groove 170, and forms a second fence 191 at the edge of the second groove 190. During the actual plastic sealing, the first fence 171 is close to the plastic sealing body 250 to prevent the plastic sealing material from overflowing during the plastic sealing, and the second fence 191 is used to prevent the plastic sealing material from crawling sideways to the molding surface 150. Through the two fence structures, the plastic sealing material can be avoided as much as possible from remaining on the surface of the heat sink body 110, thereby ensuring the heat dissipation performance and neat appearance of the chip packaging heat sink 100.

[0086] Fourth embodiment

[0087] See also Fig. 9 This embodiment provides a BGA heat dissipation package structure 200, including a substrate 230, a chip 210, a plastic package 250 and a chip package heat sink 100. The basic structure and principle of the chip package heat sink 100 and the technical effects produced are the same as those of the first embodiment or the second embodiment. For the sake of brief description, for parts not mentioned in this embodiment, reference may be made to the corresponding contents in the first embodiment or the second embodiment.

[0088] In this embodiment, the BGA heat dissipation packaging structure 200 includes a substrate 230, a chip 210, a plastic package body 250 and a chip packaging heat sink 100. The chip packaging heat sink 100 includes a heat sink body 110. The heat sink body 110 has a relative bonding surface 130 and a molding surface 150. The bonding surface 130 is used to be bonded to the plastic package body 250, and a first groove 170 is provided on the bonding surface 130, and a first fence 171 is formed at the edge of the first groove 170. The first fence 171 is surrounded by the lower edge of the heat sink body 110 to prevent the plastic sealing material from overflowing during plastic sealing; the molding surface 150 is used to combine with the mold, and a second groove 190 is provided on the molding surface 150, and a second fence 191 is formed at the edge of the second groove 190. The second fence 191 is surrounded by the upper edge of the heat sink body 110 to prevent the plastic sealing material from crawling to the molding surface 150 during plastic sealing. The chip 210 is mounted on the substrate 230 , the plastic package 250 is disposed on the substrate 230 and covers the chip 210 , and the heat sink body 110 is mounted on the plastic package 250 via the bonding surface 130 .

[0089] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A chip packaging heat sink, characterized in that: The heat sink body comprises a heat sink body, wherein the heat sink body has a relative fitting surface and a molding surface, wherein the fitting surface is used to fit on a plastic sealing body, and the fitting surface is provided with a first groove, and a first fence is formed at the edge of the first groove, and the first fence is arranged around the lower edge of the heat sink body to prevent the plastic sealing material from overflowing during plastic sealing; the molding surface is used to combine with a mold, and the molding surface is provided with a second groove, and a second fence is formed at the edge of the second groove, and the second fence is arranged around the upper edge of the heat sink body to prevent the plastic sealing material from crawling to the molding surface during plastic sealing; Wherein, a cutting path is also provided on the heat sink body, and the cutting path is provided close to the first fence and the second fence so that the first fence and the second fence can be completely removed after cutting.

2. The chip package heat sink according to claim 1, characterized in that: The depth of the first groove is 1 / 3-1 / 2 of the thickness of the heat sink body; the depth of the second groove is 1 / 3-1 / 2 of the thickness of the heat sink body.

3. The chip package heat sink according to claim 1, characterized in that: A first groove is also provided on the bottom wall of the first groove. The first groove is provided on the inner side of the first fence and is provided in a ring shape on the edge of the first groove. The first groove is used to increase the contact area between the heat sink body and the plastic packaging body during plastic packaging and prevent the plastic packaging material from overflowing.

4. The chip package heat sink according to claim 3, characterized in that: A second groove is also provided on the bottom wall of the second groove. The second groove is arranged on the inner side of the second fence and is arranged in a ring shape on the edge of the second groove. The second groove is used to store the molding material during molding to prevent the molding material from overflowing to the middle position of the molding surface.

5. The chip package heat sink according to claim 4, characterized in that: There are a plurality of first grooves, the plurality of first grooves are arranged in layers around each other, and the widths of the plurality of first grooves are the same; there are a plurality of second grooves, the plurality of second grooves are arranged in layers around each other, and the widths of the plurality of second grooves are the same.

6. The chip package heat sink according to claim 1, characterized in that: The heat sink body is rectangular in shape, and rounded structures are arranged at the four corners of the heat sink body to increase the separation angle between the heat sink body and the mold.

7. The chip package heat sink according to claim 6, characterized in that: The radius of the rounded corner structure is 2 mm.

8. The chip package heat sink according to claim 1, characterized in that: The molded surface is also electroplated to form a metal layer, and the metal layer covers the surface of the heat sink body to prevent the surface of the heat sink body from being oxidized.

9. The chip package heat sink according to claim 8, characterized in that: The bonding surface is also coated with a green paint layer or roughened by electroplating to form a tumor layer, so as to improve the bonding force between the bonding surface and the plastic packaging body.

10. A method for preparing a chip packaging heat sink, used for preparing the chip packaging heat sink as claimed in claim 1, characterized in that: include: Providing a heat sink body, the heat sink body having a mating surface and a molding surface opposite to each other; Forming a first groove on the bonding surface by laser grooving or punching process, and forming a first fence on the edge of the first groove; Forming a second groove on the molded surface by laser grooving or stamping, and forming a second fence on the edge of the second groove; The first fence is arranged around the lower edge of the heat sink body to prevent the molding compound from overflowing during molding, and the second fence is arranged around the upper edge of the heat sink body to prevent the molding compound from crawling onto the molding surface during molding.

11. A BGA heat dissipation packaging structure, characterized in that: It comprises a substrate, a chip, a plastic package and a chip packaging heat sink as described in any one of claims 1 to 9, wherein the chip is mounted on the substrate, the plastic package is arranged on the substrate and covers the chip, and the heat sink body is mounted on the plastic package through the bonding surface.

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