Preparation method of heat dissipation cover, heat dissipation cover and chip packaging structure

Abstract

The embodiment of the invention provides a preparation method of a heat dissipation cover, the heat dissipation cover and a chip packaging structure, and the method comprises the steps: providing ceramic powder and a reinforcing and toughening phase, the particle size of the ceramic powder is less than 100 [mu] m, and the mass ratio of the reinforcing and toughening phase to the ceramic powder is (0.1-1.5): 10; performing ultrasonic treatment on the reinforcing and toughening phase so as to uniformly disperse the reinforcing and toughening phase in an ultrasonic solvent; uniformly mixing the reinforcing and toughening phase with ceramic powder to form composite powder slurry, and drying the composite powder slurry to form composite powder; the composite powder is subjected to pre-pressing forming and high-temperature sintering, and a heat dissipation cover body is formed; ceramic metallization layers are formed on the inner surface and the outer surface of the heat dissipation cover body; and forming a metal coating on the welding area of the heat dissipation cover body to form the heat dissipation cover. According to the method, the heat dissipation cover which is high in heat conduction, high in toughness and high in chip thermal expansion coefficient matching degree is prepared, meanwhile, the overall weight is remarkably reduced, and the surface mounting welding requirement of a large-size flip chip is met.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the field of semiconductor packaging technology, and specifically relate to a method for preparing a heat dissipation cover, a heat dissipation cover, and a chip packaging structure. Background Art

[0002] FCBGA (Flip Chip Ball Grid Array) is an advanced packaging technology that flips the chip upside down and attaches it to the substrate, connects the chip and the substrate through solder balls, and then solders it on the PCB through SMT to achieve electrical connection and signal transmission. This packaging method can achieve higher packaging density, higher performance, lower power consumption, and higher reliability.

[0003] Existing FCBGA chips, especially those with high heat dissipation requirements, all use indium as the thermal interface material and are packaged in a form of welding with the gold-plated area of ​​the heat dissipation cover. This not only meets the heat dissipation requirements of the chip, but also reduces chip warping and protects the chip. Existing heat dissipation covers are often made of copper. Due to their high thermal conductivity (~385W / (mK)) and high strength (~300N / mm 2 ) and other characteristics, and is widely used in chip heat sinks. The raw material copper is a plate, which is formed into the required shape through stamping, forging, machining and other processes, and then the outer layer of copper is nickel-plated + gold-plated to meet the requirements of laser marking and indium welding. However, copper has many disadvantages as a heat sink.

[0004] 1) The thermal expansion coefficient of copper is about 17×10 -6 / ℃, while the thermal expansion coefficient of chip material silicon is about 2.5×10 -6 / ℃, the two are extremely mismatched, which can easily cause problems such as delamination and cracking of thermal interface materials;

[0005] 2) Copper has a high density of about 8.9g / cm 3 After the FCBGA chip is packaged, it needs to be soldered on the PCB through SMT. Especially for large-sized FCBGA chips, the weight of the package is large, which can easily cause the solder balls to collapse during the SMT process, resulting in solder ball bridging and electrical failure.

[0006] 3) Copper heat sink covers are often mass-produced through stamping, forging and other mass production methods. For some large-sized heat sink covers, stamping, forging and other methods cannot squeeze them to the edge position well to form a good molding effect, and edge collapse is prone to occur, which affects the accuracy of heat sink mounting and recognition.

[0007] In view of the above problems, it is necessary to propose a preparation method of a heat dissipation cover, a heat dissipation cover and a chip packaging structure that are reasonably designed and can effectively improve the above problems. Summary of the invention

[0008] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art, and provide a method for preparing a heat dissipation cover, a heat dissipation cover, and a chip packaging structure.

[0009] The present disclosure provides a heat dissipation cover.

[0010] One aspect of an embodiment of the present disclosure provides a method for preparing a heat dissipation cover.

[0011] The law includes:

[0012] Provide ceramic powder and a reinforcing and toughening phase, wherein the particle size of the ceramic powder is less than 100 μm, and the mass ratio of the reinforcing and toughening phase to the ceramic powder is in the range of (0.1-1.5):10;

[0013] The reinforcing and toughening phase is subjected to ultrasonic treatment to be uniformly dispersed in the ultrasonic solvent;

[0014] The reinforcing and toughening phase is mixed evenly with the ceramic powder to form a composite powder slurry, and the composite powder slurry is dried to form a composite powder;

[0015] Pre-pressing and high-temperature sintering the composite powder to form a heat dissipation cover body;

[0016] A ceramic metallization layer is formed on both the inner surface and the outer surface of the heat dissipation cover body;

[0017] A metal plating layer is formed on a welding area of ​​the heat dissipation cover body to form the heat dissipation cover.

[0018] Optionally, the reinforcing and toughening phase is one of graphite sheets, graphene nanosheets, carbon nanotubes or carbon fibers.

[0019] Optionally, the ceramic powder is one of silicon carbide, silicon nitride, aluminum nitride, magnesium oxide or beryllium oxide.

[0020] Optionally, the step of uniformly mixing the reinforcing and toughening phase with the ceramic powder to form a composite powder slurry comprises:

[0021] The uniformly dispersed reinforcing and toughening phase is mixed evenly with the ceramic powder by using a mechanical ball milling process.

[0022] Optionally, the pre-pressing of the composite powder comprises:

[0023] The composite powder is pre-pressed by dry pressing, plastic molding, slip injection molding or static pressing.

[0024] Optionally, a ceramic metallization layer is formed on both the inner surface and the outer surface of the heat dissipation cover body, including:

[0025] The ceramic metallization layer is formed on both the inner surface and the outer surface of the heat dissipation cover body by adopting a chemical plating metallization process, a direct coating metallization process, a thick film metallization process or a thin film metallization process.

[0026] Optionally, the ceramic metallization layer is a metal nickel layer.

[0027] Optionally, the heat dissipation cover body is in an inverted U shape.

[0028] Another aspect of the embodiment of the present disclosure provides a heat dissipation cover, characterized in that it is prepared by the preparation method of the heat dissipation cover described above; wherein:

[0029] The heat dissipation cover comprises a heat dissipation cover body, a ceramic metallization layer and a metal plating layer;

[0030] The ceramic metallization layer is arranged on the inner surface and the outer surface of the heat dissipation cover body;

[0031] The metal plating layer is arranged on the welding area of ​​the heat dissipation cover body.

[0032] Another aspect of the embodiment of the present disclosure provides a chip packaging structure, including a substrate, a chip and a heat dissipation cover; wherein the heat dissipation cover adopts the heat dissipation cover described above;

[0033] The chip is flipped on the substrate;

[0034] A welding metal layer is provided on a side of the chip facing away from the substrate;

[0035] The heat dissipation cover is disposed on a side of the chip away from the substrate, wherein the welding metal layer is connected to the metal plating layer of the heat dissipation cover, and an edge area of ​​the heat dissipation cover is fixed to the substrate.

[0036] The preparation method of the heat sink cover, the heat sink cover and the chip packaging structure of the disclosed embodiment utilize the advantages of high thermal conductivity, low density and low thermal expansion coefficient of high thermal conductivity ceramic powder, and improve the toughness of the ceramic powder by adding a reinforcing toughening phase, so as to prepare a solid phase composite ceramic heat sink cover with high thermal conductivity, high toughness and high matching degree with the thermal expansion coefficient of the chip. At the same time, the overall weight is significantly reduced compared with the traditional copper heat sink cover, and the SMT welding requirements of large-size FCBGA chips are met. Finally, a ceramic metallization layer is formed by ceramic metallization and a metal electroplating layer is formed by local electroplating, which gives the ceramic heat sink the ability of laser marking and indium welding. Since the particle size of the selected ceramic powder is less than 100μm, the edge collapse of the heat sink cover can be synchronously controlled to be less than 100μm through high-pressure forming and sintering, thereby ensuring the mounting accuracy of the heat sink cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1It is a schematic flow chart of a method for preparing a heat dissipation cover according to an embodiment of the present disclosure;

[0038] Figure 2 This is a scanning electron microscope image of a heat dissipation cover body after the ceramic powder material and the reinforcing and toughening phase material are mixed in one embodiment of the present disclosure;

[0039] Figure 3 This is a schematic structural diagram of a heat dissipation cover according to another embodiment of the present disclosure;

[0040] Figure 4 It is a structural schematic diagram of a chip packaging structure of another embodiment of the present disclosure. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solutions of the embodiments of the present disclosure, the embodiments of the present disclosure are further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0042] Ceramic materials refer to a type of inorganic non-metallic material made by forming and sintering inorganic compounds at high temperatures. It has the advantages of high strength, high hardness, high wear resistance, and oxidation resistance, and can be used as structural and functional materials. Among them, there are some high thermal conductivity ceramic materials.

[0043] Such as silicon carbide, silicon nitride, aluminum nitride, beryllium oxide, etc. These high thermal conductivity ceramic materials also have low thermal expansion coefficient and low density. They are ideal materials to replace copper as FCBGA chip heat sinks. In addition, the particle size of ceramic powder is controllable and can be prepared from a few microns to hundreds of microns. Through high-pressure molding, the problem of edge collapse of molded parts will be solved well, and then the problem of heat sink mounting accuracy will be solved. However, the ceramic material itself has poor toughness and is very easy to break. It has no weldability and cannot be used as a heat sink material for indium welding.

[0044] For this, Figure 1 As shown, one aspect of an embodiment of the present disclosure provides a method S100 for preparing a heat dissipation cover, and the method S100 includes:

[0045] S110, providing ceramic powder and a reinforcing and toughening phase, wherein the particle size of the ceramic powder is less than 100 μm, and the mass ratio of the reinforcing and toughening phase to the ceramic powder is in the range of (0.1-1.5):10.

[0046] Specifically, ceramic powder and a reinforcing and toughening phase are provided. In this embodiment, the reinforcing and toughening phase can be one of graphite sheets, graphene nanosheets, carbon nanotubes or carbon fibers. The ceramic powder can be one of silicon carbide, silicon nitride, aluminum nitride magnesium oxide or beryllium oxide, wherein the performance parameters of each ceramic powder are shown in Table 1. Of course, the reinforcing and toughening phase and ceramic powder can also be made of other materials, which is not specifically limited in this embodiment and can be selected according to actual needs. In addition, this embodiment does not specifically limit which ceramic body is matched with which reinforcing and toughening phase, and can be selected according to actual needs.

[0047] Among them, the particle size of the ceramic powder is less than 100μm. Through dry pressing, plastic molding, slip injection molding, isostatic pressing and other methods, a heat sink cover with no edge collapse can be formed, ensuring the mounting accuracy of the heat sink cover.

[0048] In addition, the mass ratio of the reinforcing and toughening phase to the ceramic powder is in the range of (0.1-1.5):10. That is, the mass ratio of the reinforcing and toughening phase to the ceramic powder is 1%-15%. Specifically, the weight required for each component can be calculated based on the material density of the selected ceramic powder and the selected reinforcing and toughening phase, as well as the outer dimensions of the heat dissipation cover and the predetermined percentage of the reinforcing and toughening phase. Among them, the mass ratio of the reinforcing and toughening phase to the ceramic powder is not specifically limited and can be selected according to actual needs.

[0049] Table 1 Performance parameters of each ceramic component

[0050] Ceramic powder Thermal conductivity W / (mK) Thermal expansion coefficient ppm / ℃ <![CDATA[Density g / cm 3 > Silicon Carbide 490 4.5 3.20 Silicon Nitride 320 2.6 3.12 Aluminum Nitride 320 4.5 3.26 Beryllium Oxide 310 9.2 3.01

[0051] S120, subjecting the reinforcing and toughening phase to ultrasonic treatment to uniformly disperse it in the ultrasonic solvent.

[0052] Specifically, a preset mass of the reinforcing and toughening phase is subjected to ultrasonic treatment to be uniformly dispersed in an ultrasonic solvent, wherein the ultrasonic solvent may be water or alcohol.

[0053] S130, uniformly mixing the reinforcing and toughening phase with the ceramic powder to form a composite powder slurry, and drying the composite powder slurry to form a composite powder.

[0054] Specifically, a mechanical ball milling process is used to evenly mix the uniformly dispersed reinforcing and toughening phase with the ceramic powder to form a stable and uniformly dispersed composite powder slurry, and the composite powder slurry is dried to form a composite powder.

[0055] S140, pre-pressing and high-temperature sintering the composite powder to form a heat dissipation cover body.

[0056] Specifically, the composite powder is pre-pressed by dry pressing, plastic molding, slip injection molding or static pressing, and the pre-pressed composite powder is sintered by high temperature sintering to form a stable solid phase composite ceramic heat dissipation cover body 110 .

[0057] Different from the stamping and forging forming processes used in existing copper heat sink covers, the ceramic heat sink cover containing a reinforced and toughened phase provided in the embodiments of the present disclosure adopts dry pressing, plastic molding, slip injection molding, isostatic pressing and other methods. Combined with a ceramic powder particle size of less than 100 μm, the problem of edge collapse of the heat sink cover will be well solved.

[0058] Among them, Figure 3 As shown, the heat dissipation cover body prepared is in an inverted U shape.

[0059] S150, forming a ceramic metallization layer on both the inner surface and the outer surface of the heat dissipation cover body.

[0060] Specifically, Figure 3 As shown, a ceramic metallization layer 120 is formed on both the inner surface and the outer surface of the heat dissipation cover body by using a chemical plating metallization process, a direct coating metallization process, a thick film metallization process or a thin film metallization process. In this embodiment, the ceramic metallization layer 120 may be a metal nickel layer. The ceramic metallization layer 120 may also be made of other metal materials, which is not specifically limited in this embodiment.

[0061] S160, forming a metal plating layer on the welding area of ​​the heat dissipation cover body to form the heat dissipation cover.

[0062] Specifically, the metal plating layer is plated on the welding area of ​​the heat dissipation cover body by local electroplating or chemical plating, that is, the metal plating layer is plated on the ceramic metallization layer of the bottom wall of the heat dissipation cover body. The metal plating layer can be a metal gold layer.

[0063] The preparation method of the heat dissipation cover of the disclosed embodiment uses high thermal conductivity ceramic body materials. These high thermal conductivity ceramic materials have both low thermal expansion coefficients and low densities. Under the premise of meeting the heat dissipation effect of the chip, the thermal expansion coefficient matching of the heat dissipation cover and the chip can be significantly improved, thereby avoiding problems such as delamination and cracking of the thermal interface material caused by this.

[0064] At the same time, the density of the selected ceramic material is about 1 / 3 of that of copper, which can significantly reduce the weight of the chip and avoid electrical failure caused by SMT solder ball bridging due to excessive chip weight. Secondly, due to the presence of the strengthening and toughening phase, the brittle defects of the ceramic material are also significantly improved, such as Figure 2As shown, after mechanical mixing such as ultrasound and ball milling, the ceramic material is formed and sintered, and the strengthening and toughening phase is evenly distributed in the ceramic body. When the ceramic body is subjected to pressure and breaks, the strengthening and toughening phase has a "pull-out" effect (as shown below) Figure 2 ), which can greatly consume the fracture energy, prevent the expansion of the main crack, and play a role in strengthening and toughening.

[0065] Furthermore, the ceramic metallization process is used to plate the nickel layer on the inner and outer surfaces of the heat dissipation cover body to meet the chip surface marking requirements. Finally, the gold layer is plated on the nickel layer on the inner bottom wall through local electroplating or chemical plating to meet the indium welding requirements and further meet the chip heat dissipation requirements.

[0066] Finally, since the particle size of the ceramic powder used is less than 100μm, a heat sink cover with no edge collapse can be formed through dry pressing, plastic molding, slip injection molding, isostatic pressing and other methods, ensuring the mounting accuracy of the heat sink cover.

[0067] like Figure 3 As shown, another aspect of the embodiment of the present disclosure provides a heat dissipation cover 100, which is prepared by the heat dissipation cover preparation method S100 described above; wherein, the heat dissipation cover preparation method S100 has been described in detail above and will not be repeated here.

[0068] The heat dissipation cover 100 comprises a heat dissipation cover body 110, a ceramic metallization layer 120 and a metal plating layer 130. The heat dissipation cover body 110 is composed of ceramic powder and a reinforcing and toughening phase, and the specific proportions can refer to the above description.

[0069] The ceramic metallization layer 120 is disposed on the inner and outer surfaces of the heat dissipation cover body 110 to achieve ceramic metallization of the heat dissipation cover body and meet the marking requirements of the chip surface. The ceramic metallization layer 120 can be made of metal nickel material or other metal materials, which is not specifically limited in this embodiment.

[0070] The metal plating layer 130 is disposed in the welding area of ​​the heat dissipation cover body 110. Specifically, the metal plating layer 130 is disposed on the ceramic metallization layer of the bottom wall of the heat dissipation cover body 110, and the metal plating layer 130 can be welded with the indium sheet.

[0071] The heat dissipation cover of the disclosed embodiment has a heat dissipation cover body made of a ceramic material with high thermal conductivity, low expansion coefficient and low density. Under the premise of satisfying the heat dissipation effect of the chip, the thermal expansion coefficient matching between the heat dissipation cover and the chip can be significantly improved, thereby avoiding problems such as delamination and cracking of the thermal interface material caused by this. The heat dissipation cover body has a reinforcing and toughening phase, and the brittle defects of the ceramic material are also significantly improved, which can greatly consume the fracture energy and prevent the expansion of the main crack, thereby achieving a reinforcing and toughening effect. The heat dissipation cover can also solve the problem of edge collapse, thereby greatly improving the reliability of the heat dissipation cover.

[0072] like Figure 4 As shown, another aspect of the embodiment of the present disclosure provides a chip packaging structure 200, including a substrate 210, a chip 220 and a heat dissipation cover 100; wherein the heat dissipation cover 100 adopts the heat dissipation cover 100 described above, and the specific structural features of the heat dissipation cover 100 have been described in detail above and will not be repeated here.

[0073] The chip 220 is flip-mounted on the substrate 210 via a plurality of conductive bumps. An underfill layer 221 is disposed between the chip 220 and the substrate 210 .

[0074] A soldering metal layer 230 is disposed on a side of the chip 220 facing away from the substrate 210 , wherein the soldering metal layer 230 may be an indium thermal interface material layer, that is, the soldering metal layer 230 is an indium sheet.

[0075] The heat dissipation cover 100 is disposed on a side of the chip 220 away from the substrate 210 , wherein the welding metal layer 230 is connected to the metal plating layer 130 of the heat dissipation cover 100 , and the edge area of ​​the heat dissipation cover 100 is fixed to the substrate 210 via an adhesive layer 240 .

[0076] The substrate 210 can be mounted on the printed circuit board 260 through the solder balls 250 to complete the SMT soldering of the chip packaging structure 200 .

[0077] The chip packaging structure of the disclosed embodiment adopts the heat dissipation cover mentioned above, which can significantly improve the matching of the thermal expansion coefficients of the heat dissipation cover and the chip under the premise of meeting the chip heat dissipation effect, avoiding the problems of delamination and cracking of the thermal interface material caused by this; it solves the problem of electrical failure caused by SMT solder ball bridging due to the high density of the heat dissipation cover causing the chip to be too heavy; it solves the problem of edge collapse of large-sized stamped and forged copper heat dissipation covers; it solves the problem of the heat dissipation cover being brittle and easy to break and unable to be welded with indium, and improves the reliability of the entire chip packaging structure.

[0078] In the embodiments of the present disclosure, several specific embodiments may be combined to specifically illustrate the specific process of the method for preparing the heat dissipation cover.

[0079] Example 1

[0080] In this embodiment, the ceramic powder is magnesium oxide ceramic powder, and the strengthening and toughening phase is graphene nanosheets. The preparation process of the heat dissipation cover is as follows:

[0081] The graphene nanosheets are ultrasonically treated to be uniformly dispersed in the ultrasonic solvent. 0 vol% to 15 vol% of the graphene nanosheets are added to the magnesium oxide ceramic powder, and the mixture is uniformly mixed to form a composite powder slurry, and the composite powder slurry is dried to form a composite powder. The composite powder is pre-pressed and sintered at high temperature to form a corresponding heat dissipation cover body. A ceramic metallization layer is formed on the inner surface and the outer surface of the corresponding heat dissipation cover body. A metal plating layer is formed in the welding area of ​​the corresponding heat dissipation cover body to form a corresponding heat dissipation cover.

[0082] Example 2

[0083] The flexural strength, fracture toughness and thermal conductivity of each heat dissipation cover formed in Example 1 were tested. When the content of graphene nanosheets was 2 vol%, the flexural strength and fracture toughness of the heat dissipation cover reached the maximum values, which were 265 MPa and 3.3 MPa·m respectively. 1 / 2 , compared with the heat sink cover of pure magnesium oxide ceramics, they increased by 37.3% and 32% respectively, indicating that the introduction of graphene nanosheets has a good strengthening and toughening effect on magnesium oxide ceramics.

[0084] At the same time, since the graphene nanosheets have a sheet structure, the graphene nanosheets are arranged perpendicular to the hot pressing direction during the hot pressing sintering process. When the thermal conductivity of the magnesium oxide / graphene nanosheet composite ceramics is tested along the distribution direction of the graphene nanosheets (i.e., perpendicular to the hot pressing direction), it is found that when the content of the graphene nanosheets exceeds 3 vol%, the thermal conductivity of the heat sink is basically constant at about 51 W / (m·K), and even slightly increases. When the content of the graphene nanosheets is 15 vol%, the thermal conductivity of the magnesium oxide / graphene nanosheet composite ceramics is 51.8 W / (m·K), which is close to the thermal conductivity of 55.8 W / (m·K) of the pure magnesium oxide ceramic heat sink.

[0085] In summary, according to the performance tests of the heat sink cover, it can be seen that adding graphene nanosheets to magnesium oxide ceramics can significantly enhance the mechanical properties of magnesium oxide ceramics, and can also maintain the original thermal conductivity of the ceramics, thereby enhancing the bending strength, fracture toughness and thermal conductivity of the formed heat sink cover.

[0086] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the embodiments of the present disclosure, but the embodiments of the present disclosure are not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the embodiments of the present disclosure, and these modifications and improvements are also considered to be within the protection scope of the embodiments of the present disclosure.

Claims

1. A method for preparing a heat dissipation cover, characterized in that: The method comprises: Provide ceramic powder and a reinforcing and toughening phase, wherein the particle size of the ceramic powder is less than 100 μm, and the mass ratio of the reinforcing and toughening phase to the ceramic powder is in the range of (0.1-1.5):10; The reinforcing and toughening phase is subjected to ultrasonic treatment to be uniformly dispersed in the ultrasonic solvent; The reinforcing and toughening phase is mixed evenly with the ceramic powder to form a composite powder slurry, and the composite powder slurry is dried to form a composite powder; Pre-pressing and high-temperature sintering the composite powder to form a heat dissipation cover body; A ceramic metallization layer is formed on both the inner surface and the outer surface of the heat dissipation cover body; A metal plating layer is formed on a welding area of ​​the heat dissipation cover body to form the heat dissipation cover.

2. The preparation method according to claim 1, characterized in that: The reinforcing and toughening phase is one of graphite sheets, graphene nanosheets, carbon nanotubes or carbon fibers.

3. The preparation method according to claim 1, characterized in that: The ceramic powder is one of silicon carbide, silicon nitride, aluminum nitride, magnesium oxide or beryllium oxide.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The step of uniformly mixing the reinforcing and toughening phase with the ceramic powder to form a composite powder slurry comprises: The uniformly dispersed reinforcing and toughening phase is mixed evenly with the ceramic powder by using a mechanical ball milling process.

5. The preparation method according to any one of claims 1 to 3, characterized in that: The pre-pressing of the composite powder comprises: The composite powder is pre-pressed by dry pressing, plastic molding, slip injection molding or static pressing.

6. The preparation method according to any one of claims 1 to 3, characterized in that: The inner surface and the outer surface of the heat dissipation cover body are both formed with a ceramic metallization layer, including: The ceramic metallization layer is formed on both the inner surface and the outer surface of the heat dissipation cover body by adopting a chemical plating metallization process, a direct coating metallization process, a thick film metallization process or a thin film metallization process.

7. The preparation method according to any one of claims 1 to 3, characterized in that: The ceramic metallization layer is a metal nickel layer.

8. The preparation method according to any one of claims 1 to 3, characterized in that: The heat dissipation cover body is in an inverted U shape.

9. A heat dissipation cover, characterized in that: The heat dissipation cover is prepared by the preparation method of any one of claims 1 to 8; wherein: The heat dissipation cover comprises a heat dissipation cover body, a ceramic metallization layer and a metal plating layer; The ceramic metallization layer is arranged on the inner surface and the outer surface of the heat dissipation cover body; The metal plating layer is arranged on the welding area of ​​the heat dissipation cover body.

10. A chip packaging structure, characterized in that: It comprises a substrate, a chip and a heat dissipation cover; wherein the heat dissipation cover is the heat dissipation cover according to claim 9; The chip is flipped on the substrate; A welding metal layer is provided on a side of the chip facing away from the substrate; The heat dissipation cover is disposed on a side of the chip away from the substrate, wherein the welding metal layer is connected to the metal plating layer of the heat dissipation cover, and an edge area of ​​the heat dissipation cover is fixed to the substrate.

Images