Chip heat dissipation cover plate and packaging structure
By sintering a copper powder layer on the thermal conductor of the chip heat dissipation cover plate to form a honeycomb structure, the problem of space-time cavity in the indium sheet reflow is solved, the heat dissipation effect of the chip is improved and the production cost is reduced.
Patent Information
- Application Number
- CN202421622550.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-09
- Publication Date
- 2025-04-22
- Estimated Expiration
- 2034-07-09
AI Technical Summary
In the existing chip heat dissipation structure, chemical flux residues during reflux of indium sheets will cause cavity, resulting in an increase in thermal resistance and affecting the chip heat dissipation effect.
A chip heat dissipation cover plate is designed, including a cavity at the cover plate body and a bottom. A heat conducting part is provided in the cavity. A plurality of sinking grooves are arranged at equal intervals on the thermal conducting part. A copper powder layer is sintered in each sinking groove to form a honeycomb structure to absorb gaseous substances.
By sintering the honeycomb structure of the copper powder layer, a hollow space is avoided between the thermal conductor and the indium sheet, thermal resistance is reduced, and the heat dissipation effect of the chip is improved. At the same time, the gold plating layer is eliminated, and the production cost is reduced.
Smart Images
Figure CN222785283U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of chip heat dissipation, in particular to a chip heat dissipation cover plate and a packaging structure. Background Art
[0002] With the rapid development of science and technology, chips are showing a trend of high integration, complexity and high frequency. However, the increasing heat generation of chips has become a key factor hindering the improvement of chip performance and reliability. In order to ensure the maximum performance and stability of the chip, an integrated heat sink is required to dissipate heat for the chip. However, most integrated heat sinks cannot be directly fixed on the BGA circuit board. Therefore, most manufacturers have adopted a method of setting a heat sink component above the chip and then installing the integrated heat sink on the heat sink component for heat dissipation.
[0003] In the existing chip heat dissipation structure, most of them dissipate heat or conduct heat by setting a heat dissipation cover on the chip. In this structure, it is necessary to apply a gold-plated layer on the bottom of the heat dissipation cover and set a heat-conducting layer (such as an indium sheet) between the chip and the gold-plated layer for physical mounting; however, multiple high-temperature reflows are required in reliability testing and BGA packaging processes. The residues (including solder paste solder sheets) produced by a large amount of chemical flux used to remove indium oxide during indium sheet reflow (170°C) will cause voids; the activation temperature of chemical flux is lower than the melting point of indium (156.7°C), but some of its organic components can only be completely decomposed and volatilized at higher temperatures. Any chemical residues left at the interface after the indium sheet reflow will produce gaseous voids during subsequent high-temperature reflow (up to 260°C), which is a very serious problem for BGA packaging. These voids will further expand during the reliability testing stage, causing increased thermal resistance and poor chip heat dissipation.
[0004] Therefore, there is an urgent need for a chip heat dissipation cover plate and a packaging structure to solve the above problems. Utility Model Content
[0005] Based on the above, the purpose of the present invention is to provide a chip heat dissipation cover plate and packaging structure to solve the problem that the heat dissipation of the chip is affected by the increase of thermal resistance caused by the cavity generated after the heat dissipation cover plate and the chip are packaged.
[0006] In order to solve the above technical problems, the utility model adopts the following technical solutions:
[0007] The utility model provides a chip heat dissipation cover plate, comprising a cover plate body and an air-avoiding cavity arranged on the bottom surface of the cover plate body, characterized in that a heat-conducting portion is arranged in the middle of the air-avoiding cavity, a plurality of sinking grooves are arranged on the heat-conducting portion at equal intervals, and a copper powder layer is sintered in the sinking groove;
[0008] Among them, the top surfaces of the copper powder layer and the heat conduction part are both on the same plane as the bottom of the avoidance cavity.
[0009] As an alternative technical solution of the chip heat dissipation cover plate, the heat conduction part is a rectangular structure composed of a plurality of isosceles trapezoidal support members; a plurality of the sinking grooves are arranged obliquely.
[0010] As an alternative technical solution of the chip heat dissipation cover plate, the width of the sinking groove is 0.6 mm, and the depth of the sinking groove is 0.5 mm.
[0011] As an alternative technical solution of the chip heat dissipation cover plate, the heat conduction part is a rectangular structure composed of a plurality of circular ring-shaped support members; a plurality of the sinking grooves are arranged in a ring shape; the width of the sinking groove is 0.5 mm, and the depth of the sinking groove is 0.5 mm.
[0012] As an alternative technical solution of the chip heat dissipation cover plate, sinking grooves are opened on both the longitudinal central axis and the transverse central axis of the heat conduction part.
[0013] As an alternative technical solution of the chip heat dissipation cover plate, sinking grooves are opened on the straight lines of the inner angles opposite to each other of the heat conduction part.
[0014] As an alternative technical solution of the chip heat dissipation cover plate, the heat conduction part is a rectangular structure composed of a plurality of "mouth"-shaped support members, a plurality of the sinking grooves are arranged in a "mouth" shape, with a width of 0.2 mm and a depth of 0.1 mm.
[0015] As an alternative technical solution of the chip heat dissipation cover plate, the heat conduction part is further provided with a "field"-shaped sinking groove, and the width of the "field"-shaped sinking groove is 1 mm and the depth is 0.25 mm.
[0016] As an alternative technical solution of the chip heat dissipation cover plate, a plurality of equally spaced parallel sinking grooves are opened in the heat conduction part, or a plurality of ray-shaped sinking grooves are opened in a direction from the center point of the heat conduction part to the surrounding, or a circular ring-shaped sinking groove is opened at the center of the heat conduction part, and a plurality of ray-shaped sinking grooves are opened in a direction from the circular ring-shaped sinking groove to the surrounding.
[0017] The present invention also provides a chip packaging structure, including the heat dissipation cover plate described above. A PCB substrate is attached below the heat dissipation cover plate, a chip is installed on the PCB substrate, an indium sheet is arranged above the chip, and the indium sheet is closely attached to the heat conduction part through a solder paste solder sheet.
[0018] The beneficial effects of the present invention are:
[0019] The utility model provides a chip heat dissipation cover plate and a packaging structure. The chip heat dissipation cover plate comprises a cover plate body and an air-avoiding cavity arranged on the bottom surface of the cover plate body. A heat-conducting part is arranged in the middle of the air-avoiding cavity. A plurality of sinking grooves are arranged on the heat-conducting part at equal intervals. A copper powder layer is sintered in each sinking groove. The chip packaging structure comprises a heat dissipation cover plate and a PCB substrate bonded thereto. A chip is mounted on the PCB substrate. A heat-conducting layer is arranged above the chip. The heat-conducting layer is closely bonded to the heat-conducting part through a soldering layer to conduct heat. Under the above structure, by sintering the copper powder layer in the sink on the heat conducting part, since the sintered copper powder layer has a honeycomb structure and copper is a high thermal conductivity material; therefore, when the heat dissipation cover plate and the chip are packaged and undergo reliability testing and multiple high-temperature reflows in the BGA packaging process, the gas generated will penetrate into the gaps in the copper powder layer, avoiding the generation of voids between the heat conducting part and the indium sheet to increase the thermal resistance. In addition, since the surface of the copper powder layer is not smooth, the indium sheet on the circumference of the chip is prevented from overflowing outward after liquefaction. In this structure, the gold plating layer is omitted, which not only reduces the production cost but also ensures the improvement of the heat dissipation effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is a schematic diagram of the overall structure of the heat dissipation cover plate in the first embodiment of the utility model;
[0021] Figure 2 It is a cross-sectional view of the heat dissipation cover plate in the first embodiment of the utility model;
[0022] Figure 3 This is a schematic diagram of the overall structure of the heat dissipation cover plate in the second embodiment of the present utility model;
[0023] Figure 4 It is a cross-sectional view of the heat dissipation cover plate in the second embodiment of the present utility model;
[0024] Figure 5 This is a schematic diagram of the overall structure of the heat dissipation cover plate in the third embodiment of the present utility model;
[0025] Figure 6 for Figure 5 A is an enlarged schematic diagram;
[0026] Figure 7 This is a schematic diagram of the first structural form of the heat-conducting portion of the heat dissipation cover plate in the fourth embodiment of the utility model;
[0027] Figure 8 for Figure 7 A magnified schematic diagram of B;
[0028] Fig. 9 This is a schematic diagram of the second structural form of the heat-conducting portion of the heat dissipation cover plate in the fourth embodiment of the utility model;
[0029] Fig.10 for Fig. 9A magnified schematic diagram of middle C;
[0030] Fig.11 This is a schematic diagram of the third structural form of the heat-conducting portion of the heat dissipation cover plate in the fourth embodiment of the utility model;
[0031] Fig.12 for Fig.11 A magnified schematic diagram of D in the middle;
[0032] Fig.13 It is an exploded view of the chip packaging structure in the fifth embodiment of the present utility model.
[0033] In the figure:
[0034] 1. heat dissipation cover; 11. cover body; 12. avoidance cavity; 13. heat conduction part; 131. support member; 132. sink; 2. soldering layer; 3. heat conduction layer; 4. chip; 5. PCB substrate. DETAILED DESCRIPTION
[0035] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.
[0036] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0037] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.
[0038] In the description of this embodiment, terms such as "up", "down", "left", and "right" and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of description and simplification of operation, 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. Therefore, they should not be understood as limitations on the present utility model.
[0039] In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more than two. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.
[0040] like Figures 1 to 4 As shown, the utility model provides a chip 4 heat dissipation cover plate 1, the chip 4 heat dissipation cover plate 1 includes the chip 4 heat dissipation cover plate 1 includes a cover plate body 11 and a cavity 12 arranged on the bottom surface of the cover plate body 11, a heat conduction part 13 is arranged in the middle of the cavity 12, and a plurality of sinking grooves 132 are arranged on the heat conduction part 13 at equal intervals, and a copper powder layer is sintered in each sinking groove 132; Figure 5 As shown, the utility model also provides a chip 4 packaging structure, which includes a heat dissipation cover plate 1 and a PCB substrate 5 attached thereto, a chip 4 is mounted on the PCB substrate 5, a heat conduction layer 3 is provided above the chip 4, and the heat conduction layer 3 is closely attached to the heat conduction part 13 through the soldering layer 2 for heat conduction. The top surfaces of the copper powder layer and the heat conduction part 13 are both in the same plane as the bottom of the air avoidance cavity 12.
[0041] The utility model provides a heat dissipation cover plate 1 for a chip 4 and a packaging structure, wherein a copper powder layer is sintered in a sink 132 on a heat conducting portion 13. Since the copper powder layer after sintering is a honeycomb structure and copper is a highly thermally conductive material, when the heat dissipation cover plate 1 and the chip 4 are packaged and undergo reliability testing and multiple high-temperature reflows in a BGA packaging process, the gas generated will penetrate into the gaps in the copper powder layer, thereby avoiding the generation of voids between the heat conducting portion 13 and the indium sheet and causing an increase in thermal resistance. In addition, since the surface of the copper powder layer is not smooth, the indium sheet on the circumference of the chip 4 is avoided from overflowing outward after liquefaction. In this structure, the gold-plated layer is omitted, which not only reduces the production cost but also ensures an improved heat dissipation effect.
[0042] Embodiment 1
[0043] like Figure 1 and Figure 2As shown, the heat conducting part 13 is a rectangular structure composed of a plurality of isosceles trapezoidal support members 131 of different sizes. The structure of the plurality of support members 131 can be closely attached to the chip 4 through the soldering layer 2 and the heat conducting layer 3, and the copper powder layer and the support member 131 are arranged on the same plane to ensure that the pressure exerted on the heat dissipation cover plate 1 when the chip 4 is attached and packaged is balanced and consistent, thereby preventing the risk of uneven pressure damage to the chip 4 during the packaging process; the sinking groove 132 is obliquely arranged between the support members 131 and the support members 131, and the sinking groove 132 is also provided on the circumference of the heat conducting part 13, and the sinking groove 132 is connected to the obliquely arranged sinking groove 132; When the soldering layer 2 and the thermal conductive layer 3 are reflowed at high temperature, the copper powder layer on the circumferential position of the thermal conductive part 13 can effectively prevent the thermal conductive layer 3 from overflowing outward. That is to say, compared with the traditional gold-plated layer of the heat dissipation cover plate 1, this structure reduces the production cost on the one hand, and can effectively prevent the thermal conductive layer 3 from overflowing and generating voids on the other hand, thereby improving the thermal conductivity of the chip 4. In this embodiment, the width of the sink groove 132 is 0.6 mm and the depth is 0.5 mm. Therefore, the area of the copper powder layer accounts for 27.18% mm^2, and the area of the support member 131 accounts for 71.58% mm^2, further improving the thermal conductivity of the chip 4.
[0044] Embodiment 2
[0045] like Figure 3 and Figure 4 As shown, the difference between this embodiment and the first embodiment is that: the heat conducting part 13 is a rectangular structure composed of a plurality of circular support members 131 of different sizes; a plurality of sink grooves 132 are arranged in an annular shape and are arranged between each circular support member 131, and sink grooves 132 are provided on the longitudinal center axis and the transverse center axis of the heat conducting part 13 and on the inner angle straight lines of the heat conducting part 13 opposite to each other; and sink grooves 132 are also provided on the circumference of the heat conducting part 13, and the sink grooves 132 and the annular sink grooves 132 and the longitudinal center axis and the inner angle straight lines of the heat conducting part 13 are connected to each other. The grooves 132 on the transverse central axis and on the inner angle straight lines of the heat conducting part 13 are connected to each other; when the soldering layer 2 and the heat conducting layer 3 are reflowed at high temperature, the copper powder layer on the circumferential position of the heat conducting part 13 can effectively prevent the heat conducting layer 3 from overflowing outward, and can discharge the gaseous substances at the same time; in this embodiment, the width and depth of the groove 132 are both 0.5mm; therefore, the area of the copper powder layer accounts for 26.48% mm^2, and the area of the support member 131 accounts for 72.05% mm^2; the thermal conductivity effect of the chip 4 is further improved.
[0046] Embodiment 3
[0047] like Figure 5 and Figure 6As shown, the difference between this embodiment and the above-mentioned first and second embodiments is that the heat conduction part 13 is a rectangular structure composed of a plurality of "mouth"-shaped support members 131 with different sizes. A plurality of sinking grooves 132 are arranged in a "mouth" shape between the support members 131. The width of the sinking groove 132 is 0.2 mm, and the depth is 0.1 mm. In this embodiment, since the interval distance between the sinking grooves is small, the area of the sintered copper powder is increased, that is, the contact area between the heat conduction layer (indium sheet) and the cover plate is increased, and at the same time, it can prevent the indium sheet from overflowing outward after liquefying at high temperature; further improving the heat conduction effect of the chip 4. The heat conduction part is also provided with a "field"-shaped sinking groove, and the width of the "field"-shaped sinking groove is 1 mm, and the depth is 0.25 mm. The "field"-shaped sinking groove is a guiding groove, and the gas generated during high-temperature reflow of the solder assist layer 2 and the heat conduction layer 3 can be led out through the "field"-shaped sinking groove, preventing gas cavities from being generated between the heat dissipation cover plate 1 and the chip 4, and improving the heat dissipation effect of the chip 4.
[0048] Specifically, in the above three embodiments, the heat dissipation cover plate 1 is a VC heat pipe, but it is not limited to the VC heat pipe, such as a copper material cover plate with good heat conduction; the filling material in the sinking groove 132 can not only be sintered copper powder, but also copper mesh. When the specification of the copper powder is 60-80 mesh and the specification of the copper mesh is 100 mesh, the pore size formed on the surface and inside is the most suitable, and the best effect is achieved; the high-temperature vaporized bubbles can penetrate into the pores, preventing the generation of bubbles and affecting the heat transfer resistance. In this structure, the heat conduction coefficient of the traditional heat dissipation cover plate 1 coated with a gold plating layer is 400 W / mk, and the thermal resistance ≤ 0.1 Rth. In the present invention, the heat conduction coefficient of the structure with sintered copper powder in the sinking groove 132 is 450 W / mk, and the thermal resistance ≤ 0.08 Rth. The heat conduction coefficient of the structure with sintered copper mesh in the sinking groove 132 is 450 W / mk, and the thermal resistance ≤ 0.09 Rth; therefore, compared with the traditional heat dissipation cover plate 1, the structure of sintering copper powder or copper mesh in the sinking groove 132 with different shapes has improved effects in terms of thermal resistance and heat conduction coefficient performance, preventing the problem of thermal failure of the chip 4 caused by bubbles, and at the same time reducing the production cost.
[0049] Embodiment Four
[0050] As Figures 7 and 8 shown, a plurality of sinking grooves with equal spacing and parallel are opened on the heat conduction part 13;
[0051] As Figures 9 and 10 shown, a plurality of ray-shaped sinking grooves are opened in the direction from the center point of the heat conduction part 13 to the surrounding;
[0052] As Figure 11 to Figure 12 shown, a plurality of circular sinking grooves are opened on the heat conduction part 13, and a plurality of ray-shaped sinking grooves are opened in the direction from the circular sinking groove at the center of the heat conduction part to the surrounding;
[0053] In this embodiment, the sink grooves provided on the heat conducting part include but are not limited to the above various shapes or layouts; and the sink grooves of various shapes provided on the heat conducting part are all guide channels, which are helpful for the gas generated by the soldering layer 2 and the heat conducting layer 3 during high-temperature reflow to be discharged outwardly; prevent the generation of gaseous cavities between the heat dissipation cover plate 1 and the chip 4, thereby improving the heat dissipation effect of the chip 4. On the other hand, in this embodiment, a concave-convex part is formed between the sink groove 132 and the support member 131, and when the indium sheet is used as a heat conducting layer, the indium sheet will not overflow outward after being liquefied at high temperature, thereby preventing the generation of cavities between the chip and the heat dissipation cover plate 1, further improving the heat dissipation effect of the chip 4.
[0054] Embodiment 5
[0055] like Fig.13 As shown, the utility model also provides a chip 4 packaging structure, including the heat dissipation cover plate 1 in the above embodiment, a PCB substrate 5 is attached below the heat dissipation cover plate 1, a chip 4 is mounted on the PCB substrate 5, a heat conduction layer 3 is provided above the chip 4, and the heat conduction layer 3 is tightly attached to the heat conduction part 13 through the soldering layer 2. Among them, the heat conduction layer 3 is preferably an indium sheet, but not limited to an indium sheet; the soldering layer 2 is preferably a solder paste sheet, but not limited to a solder paste sheet. The chip 4 packaging structure not only reduces the manufacturing cost, but more importantly, by setting the sink 132 and the structure of sintering copper powder or copper mesh in the sink 132, the bubbles generated during high-temperature reflow can penetrate into its pores, preventing the problem of bubbles causing thermal failure of the chip 4, and also solving the problem of overflow of the heat conduction layer 3 at the circumferential position of the chip 4, thereby improving the heat dissipation efficiency of the chip 4.
[0056] The above is only a preferred embodiment of the utility model, and does not limit the utility model in any form. Although the utility model is disclosed as a preferred embodiment as above, it is not used to limit the utility model. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above without departing from the scope of the technical solution of the utility model. However, any simple modification, equivalent change and modification made to the above embodiments according to the technology of the utility model, which does not depart from the content of the technical solution of the utility model, belongs to the scope of the technical solution of the utility model.
Claims
1. A chip heat dissipation cover plate, comprising a cover plate body and a cavity provided on the bottom surface of the cover plate body, characterized in that: A heat-conducting part is provided in the middle of the cavity-avoiding cavity. A plurality of sinking grooves are equidistantly formed on the heat-conducting part, and a copper powder layer is sintered in the sinking grooves; Wherein, the top surface of the copper powder layer and the heat-conducting part are both in the same plane as the bottom of the cavity-avoiding cavity.
2. A chip heat dissipation cover plate according to claim 1, characterized in that: The heat-conducting part is a rectangular structure composed of a plurality of isosceles trapezoidal support members; a plurality of the sinking grooves are arranged obliquely.
3. A chip heat dissipation cover plate according to claim 2, characterized in that: The width of the sinking groove is 0.6 mm, and the depth of the sinking groove is 0.5 mm.
4. The chip heat dissipation cover plate according to claim 1, characterized in that: The heat-conducting part is a rectangular structure composed of a plurality of circular ring-shaped support members; a plurality of the sinking grooves are arranged in a circular shape; the width of the sinking groove is 0.5 mm, and the depth of the sinking groove is 0.5 mm.
5. The chip heat dissipation cover plate according to claim 4, characterized in that: Sinking grooves are formed on both the longitudinal central axis and the transverse central axis of the heat-conducting part.
6. The chip heat dissipation cover plate according to claim 5, characterized in that: Sinking grooves are formed on the straight lines of the inner angles opposite to each other of the heat-conducting part.
7. The chip heat dissipation cover plate according to claim 1, characterized in that: The heat-conducting part is a rectangular structure composed of a plurality of "mouth"-shaped support members, a plurality of the sinking grooves are arranged in a "mouth" shape, with a width of 0.2 mm and a depth of 0.1 mm.
8. The chip heat dissipation cover plate according to claim 7, characterized in that: The heat-conducting part is further provided with a "field"-shaped sinking groove, and the width of the "field"-shaped sinking groove is 1 mm and the depth is 0.25 mm.
9. The chip heat dissipation cover plate according to claim 1, characterized in that: The heat-conducting part is provided with a plurality of equidistantly parallel sinking grooves, or a plurality of ray-shaped sinking grooves opened in the direction from the center point of the heat-conducting part to the surrounding, or a circular ring-shaped sinking groove is opened at the center of the heat-conducting part, and a plurality of ray-shaped sinking grooves are opened in the direction from the circular ring-shaped sinking groove to the surrounding.
10. A chip packaging structure, comprising the heat dissipation cover plate according to any one of claims 1 to 9, characterized in that: A PCB substrate is attached to the lower side of the heat dissipation cover plate. A chip is installed on the PCB substrate. An indium sheet is provided above the chip, and the indium sheet is tightly attached to the heat-conducting part through a solder paste solder sheet.