Heat dissipation cover packaging structure

Abstract

The invention provides a heat dissipation cover attaching structure, which is characterized by comprising a substrate, a first metal ring, a second metal ring and a heat dissipation cover, the bottom end of the side wall of the heat dissipation cover is in contact with the substrate, and a second metal ring is arranged at the bottom end of the side wall of the heat dissipation cover; the first metal ring is provided with a first groove, and the second metal ring is provided with a second groove; a guide groove formed in the contact face of the heat dissipation cover and the substrate is formed between the heat dissipation cover and the substrate through the first groove and the second groove, and high-temperature welding flux is arranged in the guide groove. The heat dissipation cover and the substrate can be applied to a large-size FCBGA attaching cover structure, the problem that the heat dissipation cover falls off is solved, the substrate is pulled through welding of the metal ring, and therefore the heat dissipation effect is improved. The bonding force between the substrate and the heat dissipation cover is increased, and the overall flatness is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor packaging, and in particular to a heat dissipation cover packaging structure. Background Art

[0002] In the existing process, as the functional requirements of FCBGA increase, the chip size and the required components become larger and more numerous. Under the current technology, insulating glue is usually used to bond the heat dissipation cover. However, due to the increase in chip size, the existing bonding area and the bonding force brought by the insulating glue may not meet the bonding requirements, and the risk of cover falling off also increases. Summary of the invention

[0003] The present invention aims to provide a heat dissipation cover welding and pasting cover structure to overcome the risk that the bonding force in the prior art cannot meet the bonding requirements.

[0004] The present invention provides a heat dissipation cover packaging structure, characterized by comprising:

[0005] A substrate, wherein the substrate is provided with a first metal ring;

[0006] A heat dissipation cover, wherein the bottom end of the side wall of the heat dissipation cover contacts the substrate, and a second metal ring is provided at the bottom end of the side wall of the heat dissipation cover;

[0007] The first metal ring is provided with a first groove, and the second metal ring is provided with a second groove;

[0008] A guide groove arranged on the contact surface of the heat dissipation cover and the base plate is formed between the heat dissipation cover and the base plate through the first groove and the second groove, and high temperature solder is contained in the guide groove.

[0009] In one embodiment of the present invention, the heat dissipation cover packaging structure further comprises a chip, the chip is mounted on the substrate, the top of the chip is coated with heat dissipation glue and is in contact with and fits with the top of the heat dissipation cover.

[0010] In another embodiment of the present invention, the metal ring is a copper layer.

[0011] In another embodiment of the present invention, the metal ring is arranged in a ring shape along the epitaxial contact surface between the substrate and the heat dissipation cover.

[0012] In another embodiment of the present invention, the groove is arranged in a ring shape along the metal ring.

[0013] In another embodiment of the present invention, when the heat dissipation cover is mounted on the substrate, the second metal ring completely overlaps or at least partially overlaps with the first metal ring.

[0014] The present invention also provides a heat dissipation cover packaging method, characterized by comprising:

[0015] Forming metal rings and making grooves, forming a first metal ring on the substrate, and forming a second metal ring at the bottom of the side wall of the heat dissipation cover, then forming a first groove in the first metal ring, and forming a second groove in the second metal ring;

[0016] Spraying solder, spraying solder in the first groove, and applying heat dissipation glue on the surface of the chip;

[0017] Mounting a heat dissipation cover, attaching the heat dissipation cover to the substrate so that the surface of the chip contacts the top surface of the heat dissipation cover; and

[0018] Reflow soldering is a process of high-frequency rapid heating and reflow process on the interface to complete the soldering of the metal rings and solder on both sides.

[0019] In one embodiment of the present invention, the step of attaching the heat dissipation cover further includes: overlapping the first metal ring with the second metal ring or at least partially overlapping the first groove with the second groove, and the first groove and the second groove are interconnected and spliced ​​to form a guide groove.

[0020] In another embodiment of the present invention, the step of forming the metal ring further comprises: substrate surface treatment, by treating the substrate surface to remove surface material to form the first metal ring; and

[0021] The heat dissipation cover surface is treated by treating the bottom of the side wall of the heat dissipation cover to remove the surface material and form the second metal ring.

[0022] In another embodiment of the present invention, the first groove and the second groove are formed in the first metal ring and the second metal ring by etching or embossing process.

[0023] Compared with the prior art, the present invention provides a heat dissipation cover-cover packaging structure. Compared with the traditional heat dissipation cover-cover structure, the present invention has the following beneficial effects:

[0024] Compared with the prior art, the exposed copper portion is concavely designed so that the solder can flow in the groove, thereby improving the overall flatness of the heat dissipation cover after being combined with the substrate.

[0025] Compared with the traditional bonding with insulating glue, by exposing the metal ring and welding the copper layer after the heat dissipation cover is attached to the substrate, the bonding force between the substrate and the heat dissipation cover is greatly increased, reducing the risk of the cover falling off.

[0026] Therefore, the present invention provides a structure for achieving welding connection between a heat dissipation cover and a substrate joint surface. Compared with the existing technology, this structure can solve the problem of cover falling off of large PKG FCBGA products and improve the overall flatness. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a packaging structure in an embodiment of the present invention is shown;

[0028] Figure 2 A schematic diagram of the structure of a substrate in one embodiment of the present invention is shown;

[0029] Figure 3 A schematic diagram of the heat dissipation cover structure in one embodiment of the present invention is shown; and

[0030] Figure 4 A heat dissipation cover packaging flow chart in an embodiment of the present invention is shown. Specific embodiments

[0031] In the following description, the present invention is described with reference to various embodiments. However, those skilled in the art will recognize that

[0032] It is recognized that the embodiments may be implemented without one or more of the specific details or with other alternative and / or additional methods, materials or components. In other cases, well-known structures, materials or operations are not shown or described in detail to avoid obscuring the inventive point of the present invention. Similarly, for the purpose of explanation, specific quantities, materials and configurations are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, the present invention is not limited to these specific details.

[0033] Furthermore, it is to be understood that the various embodiments shown in the Figures are illustrative representations and are not necessarily drawn to scale.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than explicitly or implicitly indicating that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as expressing or implying relative importance. In this specification, reference to "one embodiment" or "the embodiment" means that a particular feature, structure or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present invention. The phrase "in one embodiment" appearing in various places in this specification does not necessarily refer to the same embodiment.

[0036] Figure 1 A cross-sectional schematic diagram of a heat dissipation cover packaging structure in an embodiment of the present invention is shown.

[0037] like Figure 1 As shown, the present invention provides a heat dissipation cover packaging structure, including: a substrate 1, a heat dissipation cover 2 and a chip 3.

[0038] In an embodiment of the present invention, the substrate 1 may be a PCB circuit board, and the chip 3 is mounted on the substrate 1 by processes such as wire bonding and flip-chip soldering. A first metal ring 101 surrounding the chip 3 is provided on the substrate 1. The first metal ring 101 may be a metal ring exposed by removing a portion of the surface insulating layer of the substrate 1. Alternatively, the first metal ring 101 may be a metal ring formed on the surface of the substrate 1 by other processes.

[0039] The heat dissipation cover 2 covers the chip 3 and includes a top and a side wall. The top of the heat dissipation cover 2 contacts the top of the chip 3. The bottom of the side wall of the heat dissipation cover 2 contacts the substrate. The heat dissipation cover 2 is sealed and connected to the substrate 1 to form a sealed space for accommodating the chip 3. The material of the heat dissipation cover 2 can be metal or other materials with good thermal conductivity.

[0040] The bottom end of the side wall of the heat dissipation cover has a second metal ring 201. The second metal ring 201 matches the shape of the first metal ring 101. When the heat dissipation cover 2 is mounted on the substrate 1, the second metal ring 201 completely overlaps with the first metal ring 101 or at least partially overlaps.

[0041] In one embodiment of the present invention, the main material of the heat dissipation cover 2 is copper, and the surface is a nickel-plated protective layer. The second metal ring 201 at the bottom end of the side wall of the heat dissipation cover is formed by removing the nickel-plated protective layer on the surface of the bottom end of the side wall. In other embodiments of the present invention, the main material of the heat dissipation cover 2 can be other materials, and the second metal ring 201 can be formed by processes such as electroplating and physical vapor deposition.

[0042] Chip 3 can be a logic chip such as CPU, DSP, GPU, FPGA, etc., or a storage chip such as DRAM, Flash, etc., or other types of chips such as SOC or sensors (such as MEMS sensors, etc.). Compared with the prior art, the current prior art uses insulating glue to bond the substrate and the heat dissipation cover, but in the actual production process, due to the possibility of contamination, if the bonding surface is contaminated, it may cause the bonding to be unreliable, resulting in an increased risk of the cover falling off. In the conventional technical scheme, there is green oil on the surface of the substrate and the surface of the heat dissipation cover is nickel-plated. In view of this structure, the present invention adopts a removal process for the contact part between the substrate and the heat dissipation surface, removes part of the surface material, and obtains a bare metal layer as the first metal ring and the second metal ring.

[0043] The present invention further designs the first metal ring and the second metal ring to be concave, replaces the traditional bonding method of using insulating glue with solder filling in the groove, and welds the metal layer, thereby greatly increasing the bonding force between the heat dissipation cover and the substrate, thereby greatly reducing the risk of the heat dissipation cover falling off. And the use of solder welding can also optimize the flatness.

[0044] In the present invention, heat is conducted from the substrate 1 to the heat dissipation cover 2 through the first metal ring and the second metal ring. At the same time, heat dissipation glue is applied on the top of the chip 3 and contacts the heat dissipation cover 2 to conduct heat from the chip 3 to the heat dissipation cover 2, thereby realizing two heat dissipation pathways, that is, heat transfer from the chip 3 to the heat dissipation cover 2 and heat transfer from the substrate 1 to the heat dissipation cover 2, thereby realizing overall heat conduction and heat dissipation.

[0045] In one embodiment of the present invention, the material of the first metal ring and the second metal ring may be copper. Obviously, the metal layer may be replaced by other metals, and the present invention does not impose any specific limitation thereto.

[0046] Figure 2 A three-dimensional schematic diagram and a cross-sectional schematic diagram of a substrate structure in an embodiment of the present invention are shown.

[0047] like Figure 2 The substrate 1 is shown as being provided with a first metal ring 101 in the peripheral welding area. The metal ring is provided in a ring shape along the epitaxial contact surface of the substrate 1, and the chip 3 is provided in the center. The first metal ring 101 is designed to be concave, forming a first groove 102. The first groove 102 runs through the first metal ring 101 and is an annular groove. Through the groove 102, when the solder is sprayed, the high-temperature solder can flow in the groove 102, thereby discharging bubbles in the solder and optimizing the overall flatness.

[0048] Figure 3 A three-dimensional schematic diagram and a cross-sectional schematic diagram of a heat dissipation cover structure in an embodiment of the present invention are shown.

[0049] like Figure 3 As shown, a circle of exposed metal rings is provided in the welding area of ​​the side wall of the heat dissipation cover 3, which is the second metal ring 201. The second metal ring 201 corresponds to the first metal ring 101, and is also concavely designed to form a second groove 202. The first groove 102 and the second groove 202 correspond to each other, forming a guide groove surrounding the packaging structure to fill high-temperature solder to weld the substrate 1 and the heat dissipation cover 2. The area of ​​the second metal ring 201 is roughly equal to that of the first metal ring 101.

[0050] The second metal ring 201 includes a second groove 202 penetrating the second metal ring 201 . The first groove 102 cooperates with the second groove 202 to form a guide groove S. That is, the guide groove S is located between the second groove 202 penetrating the second metal ring 201 and the first groove 102 .

[0051] Here, "the first groove 102 cooperates with the second groove 202" means that the position of the first groove 102 and the position of the second groove 202 match each other. When the first groove 102 and the second groove 202 cooperate with each other, the first groove 102 and the second groove 202 are connected to each other and spliced ​​to form a guide groove S, and the volume of the guide groove S is roughly the sum of the volumes of the groove 102 and the groove 202.

[0052] In summary, a guide groove S is formed between the heat dissipation cover 2 and the substrate 1 of the present invention and is disposed on the contact surface of the two. In addition to flowing between the substrate 1 and the heat dissipation cover 2, the solder 4 can also flow in the guide groove S. The heat dissipation cover 2 is fixed on the substrate 1 by the solder 4 disposed in the guide groove S. In one embodiment of the present invention, the solder 4 is solder paste.

[0053] In addition, the shape of the first groove 102 can be consistent with that of the second groove 202. For example, the groove 102 and the groove 202 are both arranged in a square shape, but the present invention is not limited thereto. Figure 2 and Figure 3 In the illustrated embodiment, the cross-sections of the grooves 102 and 202 are rectangular. However, in other embodiments of the present invention, the cross-sections of the grooves 102 and 202 may be triangular, trapezoidal, semicircular, or the like.

[0054] Figure 4 A cross-sectional schematic diagram of a heat dissipation cover-on-cover packaging process according to an embodiment of the present invention is shown.

[0055] like Figure 4 As shown, first, in step S1, a first metal ring is formed on a substrate, and a second metal ring is formed at the bottom of the side wall of a heat dissipation cover, and then a first groove is formed in the first metal ring, and a second groove is formed in the second metal ring. A chip is mounted on the substrate. In an embodiment of the present invention, the first metal ring can be formed by removing part of the insulating layer on the surface of the substrate. The second metal ring can be formed by removing the surface nickel layer at the bottom of the side wall of the heat dissipation cover. In other embodiments of the present invention, the first metal ring can be formed on the surface of the substrate by a metal deposition process.

[0056] In the embodiment of the present invention, the first groove and the second groove may be formed in the first metal ring and the second metal ring by etching, stamping or other processes.

[0057] The first metal ring and the second metal ring correspond to each other, and the first groove and the second groove correspond to each other.

[0058] Next, in step S2, high temperature solder is sprayed on the first groove 102 on the substrate, and heat dissipation glue is applied on the surface of the chip. In one embodiment of the present invention, the solder is solder paste.

[0059] Next, in step S3, the heat dissipation cover is attached to the substrate so that the chip surface contacts the top surface of the heat dissipation cover, and the first metal ring overlaps or at least partially overlaps the second metal ring, and the first groove and the second groove are interconnected and spliced ​​to form a guide groove.

[0060] Next, in step S4, high-frequency rapid heating and a reflow process are performed on the interface to complete the welding of the metal rings and solders on both sides.

[0061] This process realizes the encapsulation of the heat sink cover and the substrate, and uses high-temperature solder to weld by designing the groove, thereby increasing the bonding force between the heat sink cover and the substrate. The process is simple and has very good feasibility. It can be applied to large-size FCBGA cover structures to solve the problem of heat sink cover falling off, and pull the substrate through strong bonding force to improve the overall flatness.

[0062] The present invention has been described by the above-mentioned relevant embodiments, however, the above-mentioned embodiments are only examples for implementing the present invention. In addition, the technical features involved in the different embodiments of the present invention described above can be combined with each other as long as they do not conflict with each other. It must be pointed out that the present invention can also have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all belong to the protection scope of the claims attached to the present invention.

Claims

1. A heat dissipation cover packaging structure, characterized in that: include: A substrate, wherein the substrate is provided with a first metal ring; A heat dissipation cover, wherein the bottom end of the side wall of the heat dissipation cover contacts the substrate, and a second metal ring is provided at the bottom end of the side wall of the heat dissipation cover; The first metal ring is provided with a first groove, and the second metal ring is provided with a second groove; A guide groove arranged on the contact surface of the heat dissipation cover and the base plate is formed between the heat dissipation cover and the base plate through the first groove and the second groove, and high temperature solder is contained in the guide groove.

2. The structure according to claim 1, characterized in that The heat dissipation cover packaging structure also includes a chip, which is mounted on the substrate. The top of the chip is coated with heat dissipation glue and is in contact with and fits with the top of the heat dissipation cover.

3. The structure according to claim 1, characterized in that The metal ring is a copper layer.

4. The structure according to claim 1, characterized in that The metal ring is arranged in a ring shape along the epitaxial contact surface between the substrate and the heat dissipation cover.

5. The structure according to claim 4, characterized in that The groove is arranged in a ring shape along the corresponding metal ring.

6. The structure according to claim 4, characterized in that When the heat dissipation cover is mounted on the substrate, the second metal ring completely overlaps or at least partially overlaps with the first metal ring.

7. A heat dissipation cover packaging method, characterized in that: include: Forming metal rings and making grooves, forming a first metal ring on the substrate, and forming a second metal ring at the bottom of the side wall of the heat dissipation cover, then forming a first groove in the first metal ring, and forming a second groove in the second metal ring; Spraying solder, spraying solder in the first groove, and applying heat dissipation glue on the surface of the chip; Mounting a heat dissipation cover, and attaching the heat dissipation cover to the substrate so that the surface of the chip contacts the top surface of the heat dissipation cover; as well as Reflow soldering is a process of high-frequency rapid heating and reflow process on the interface to complete the soldering of the metal rings and solder on both sides.

8. The packaging method according to claim 7, characterized in that: The step of attaching the heat dissipation cover also includes: overlapping the first metal ring with the second metal ring or at least partially overlapping the first groove with the second groove, and the first groove and the second groove are connected to each other and spliced ​​to form a guide groove.

9. The packaging method according to claim 7, characterized in that: The step of forming the metal ring further includes: substrate surface treatment, by treating the substrate surface to remove surface material to form the first metal ring; and The heat dissipation cover surface is treated by treating the bottom of the side wall of the heat dissipation cover to remove the surface material and form the second metal ring.

10. The packaging method according to claim 7, characterized in that: The first groove and the second groove are formed in the first metal ring and the second metal ring by etching or embossing process.

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