Heat dissipation patch, circuit board and electronic device
By designing multiple heat dissipation holes in the heat dissipation patch and optimizing the structure of the adhesive layer and protective layer, the problems of poor heat dissipation effect and uneven adhesion in the prior art are solved, and more efficient heat conduction and more stable adhesion effect are achieved.
Patent Information
- Application Number
- CN202421636121.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-10
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2034-07-10
AI Technical Summary
In actual applications, existing heat dissipation patches have problems such as poor heat dissipation effect and uneven attachment and easy bending to cause edge peeling.
A heat dissipation patch including a first adhesive layer, a heat dissipation layer, a protective layer and a plurality of heat dissipation holes is designed. The heat dissipation hole extends downward from the upper surface of the protective layer, with the bottom not lower than the upper surface of the first adhesive layer, for improving heat conduction efficiency, and by optimizing the material and structure of the adhesive layer and the protective layer, reducing stress and maintaining the adhesion flatness.
By increasing the number and location of the heat dissipation holes, the heat conduction efficiency is significantly improved and the heat dissipation effect is improved. At the same time, the optimized structural design reduces stress and avoids the problems of unevenness of the adhesion and edge peeling.
Smart Images
Figure CN222869261U_ABST
Abstract
Description
Technical Field
[0001] This case involves a heat sink and a circuit board and an electronic device having the heat sink. Background Art
[0002] In the prior art, a chip is generally placed on a printed circuit board, and a flexible circuit substrate (such as a tape carrier package (TCP) or a chip on film (COF)) is often used in electronic devices with limited space to carry the chip because it is bendable.
[0003] The chip or other electronic components on the circuit board will generate heat during operation. In order to increase the heat dissipation effect, a heat sink is usually attached to the circuit board and covers the chip or other heat-generating electronic components.
[0004] In this regard, reference may be made to, for example, Patent Document 1 (Taiwan Patent Publication No. 202207383), which Figure 3 Specifically disclosed is a display device, which includes a flexible circuit substrate in the form of a film flip chip package, and the flexible circuit substrate has a chip as a driver IC of a display panel, and a heat sink attached to the circuit board and covering the chip (for details, refer to patent document 1 Figure 2 A and Figure 2 B). In particular, the heat sink is also a flexible heat sink that can be bent along with the flexible circuit substrate to be suitable for electronic devices with small spaces. For other similar heat sinks, reference can be made to, for example, Patent Document 2 (Taiwan Patent Publication No. 202221868) of the same applicant. Utility Model Content
[0005] After research, the inventor of this case found that the above-mentioned prior art still has many problems in practice. For example, in Patent Documents 1 and 2, the downward side of the heat sink patch is adhered to the circuit board or chip using an adhesive (such as pressure-sensitive adhesive, thermosetting resin and other adhesive materials), and the upward side of the heat sink patch has an insulating protective layer. The insulating protective layer is generally a polymer material such as polyimide (PI) and other insulating materials to provide the heat sink patch with insulation effect and sufficient mechanical strength. Although the heat sink patch has a heat dissipation layer (such as a metal layer or graphite) to assist the circuit board or chip below in heat dissipation, compared with the heat sink layer, polyimide itself is not a good thermal conductive material (its thermal conductivity is about 0.2~2W / mk), so the heat conducted from the circuit board or chip to the heat sink layer cannot be further quickly conducted to the outside world for natural convection, so the overall heat dissipation effect of the existing heat sink patch still has room for improvement.
[0006] In addition, it is also found that when the existing heat sink is attached to the circuit board, it does not remain flat, but bends, as shown in Patent Document 1. Figure 2 A and Figure 2 Moreover, if the heat sink is attached to the bendable area of the circuit board, the degree of bending is greater, that is, as shown in Patent Document 1 Figure 3 In this case, the edge of the small-area heat sink is easily peeled off from the circuit board due to stress, which is also an area that needs to be improved.
[0007] In view of the above, an embodiment of the present invention proposes a heat dissipation patch for adhering a circuit board, the heat dissipation patch comprising: a first adhesive layer, the first adhesive layer is used to adhere to the circuit board; a heat dissipation layer, arranged above the first adhesive layer; a protective layer; arranged above the heat dissipation layer; a plurality of heat dissipation holes, the plurality of heat dissipation holes extend downward from the upper surface of the protective layer, and the bottoms of the plurality of heat dissipation holes are not lower than the upper surface of the first adhesive layer.
[0008] Preferably, the bottoms of the plurality of heat dissipation holes are located in the heat dissipation layer.
[0009] Preferably, the bottoms of the plurality of heat dissipation holes are not lower than the upper surface of the heat dissipation layer.
[0010] Preferably, the heat dissipation patch further includes a heat diffusion layer disposed between the heat dissipation layer and the protective layer, wherein the bottom of the plurality of heat dissipation holes is not lower than the upper surface of the heat diffusion layer, wherein the horizontal thermal conductivity of the heat diffusion layer is at least 50% higher than the vertical thermal conductivity.
[0011] Preferably, the heat dissipation patch further comprises a heat diffusion layer located at the bottom of the plurality of heat dissipation holes, wherein the thermal conductivity of the heat diffusion layer in a horizontal direction is at least 50% higher than the thermal conductivity in a vertical direction.
[0012] Preferably, the heat dissipation patch further includes a second adhesive layer disposed between the heat dissipation layer and the protective layer, wherein the bottoms of the plurality of heat dissipation holes are lower than the lower surface of the protective layer.
[0013] Preferably, the bottoms of the plurality of heat dissipation holes are lower than 2 / 3 of the thickness of the second adhesive layer.
[0014] Preferably, the plurality of heat dissipation holes are also filled with a heat dissipation glue.
[0015] Preferably, the plurality of heat dissipation holes are further filled with a heat conductive metal.
[0016] Preferably, the diameter of the plurality of heat dissipation holes is at least 0.5 mm.
[0017] Preferably, the spacing between the plurality of heat dissipation holes is at least 1 mm.
[0018] Preferably, the distance between the plurality of heat dissipation holes and an edge of the heat dissipation patch is no more than 6 mm.
[0019] Preferably, the heat dissipation patch has two opposite edges, and the distance between the plurality of heat dissipation holes and one of the two edges does not exceed 25% of the distance between the two edges.
[0020] In addition, another embodiment of the present invention further proposes a heat dissipation patch for adhering a circuit board, the heat dissipation patch comprising: a first adhesive layer, the first adhesive layer is used to adhere to the circuit board; a heat dissipation layer, arranged above the first adhesive layer; a protective layer; arranged above the heat dissipation layer; a plurality of heat dissipation holes, the plurality of heat dissipation holes extending downward from the upper surface of the protective layer; wherein the heat dissipation patch has two opposite edges, and the distance between the plurality of heat dissipation holes and one of the two edges is less than 25% of the distance between the two edges.
[0021] The present embodiment also provides a circuit board, comprising: a substrate having a circuit layer; and the heat dissipation patch as described above, the heat dissipation patch being attached to the substrate.
[0022] The present embodiment further provides an electronic device, comprising: the circuit board as described above; and a chip disposed on the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 This is a schematic diagram of the structure of the heat dissipation patch according to the first embodiment of the present invention;
[0024] Figures 2 to 10 It is a schematic diagram of the structure of the heat dissipation patch according to other different embodiments of the present invention;
[0025] Fig.11 A top view of a heat dissipation patch according to an embodiment of the present invention;
[0026] Fig.12 FIG. 4 is a schematic diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION
[0027] The following will refer to the attached drawings to demonstrate the preferred embodiments of the present invention. To avoid blurring the content of the present invention, the following description also omits existing components, related materials, and related processing technologies. At the same time, to clearly illustrate the present invention, the components in the attached drawings may not be drawn according to actual sizes or relative proportions.
[0028] Please refer to Figure 1The side view shown is a first embodiment of the heat sink 10 of the present invention. The heat sink 10 is used to be attached to the circuit board 1 and / or the chip 2. The circuit board 1 and the chip 2 can refer to the flexible circuit substrate in the prior art (such as tape carrier package (TCP) or chip on film (COF)), and the heat sink 10 can be attached to the bendable area of the circuit board 1 (not shown).
[0029] As shown in the figure, the heat dissipation patch 10 includes a first adhesive layer 20 , a heat dissipation layer 30 , a second adhesive layer 40 , and a protective layer 50 .
[0030] The first adhesive layer 20 is used to contact and adhere to the circuit board 1 and / or the chip 2 downwards, and to contact and adhere to the heat dissipation layer 30 upwards. The material of the first adhesive layer 20 can be selected from adhesive materials such as double-sided adhesive, pressure-sensitive adhesive, and thermosetting resin, and its thickness is usually not less than 1 μm. For example, the first adhesive layer 20 can be 8805 thermal conductive tape from 3M Company.
[0031] The material of the heat dissipation layer 30 can be selected from heat-conducting / heat-dissipating materials such as metal and graphite. Preferably, the heat dissipation layer 30 can be copper foil or aluminum foil.
[0032] The second adhesive layer 40 is used to contact and adhere to the heat dissipation layer 30 downwards, and to contact and adhere to the protection layer 50 upwards. The material of the second adhesive layer 40 can be the same or similar to that of the first adhesive layer 20.
[0033] The material of the protective layer 50 can be selected from insulating materials such as organic polymer materials, and is also called an insulating layer. Preferably, the protective layer 50 can be a polyimide (PI, polyimide) film.
[0034] Further, if Figure 1 As shown, the heat sink patch 10 is characterized by having a plurality of heat dissipation holes 100. In one embodiment, the aperture of the heat dissipation hole 100 is at least 0.5 mm, or for example, it can be 1 mm or 1.2 mm, and the spacing between the heat dissipation holes 100 is at least 1 mm. The heat dissipation holes 100 extend downward from the upper surface of the protective layer 50 to the upper surface of the heat dissipation layer 30, thereby exposing the entire heat dissipation layer 30. Therefore, the heat accumulated in the heat dissipation layer 30 can be more quickly conducted to the outside through the path outside the second adhesive layer 40 and the protective layer 50 (i.e., the heat dissipation holes 100). The method for forming the heat dissipation holes 100 can be utilized, for example, by mechanical drilling (Mechanical Drilling) or laser drilling (Laser Drilling). It should be noted that, Figure 1 For the purpose of illustration, only three heat dissipation holes 100 are shown. However, in practice, the number of heat dissipation holes 100 may be greater, and this is not intended to be limited in the present invention.
[0035] It is also worth noting that Figure 1 In the embodiment of the present invention, the heat dissipation hole 100 penetrates the protective layer 50 and the second adhesive layer 40, and the bottom thereof is located on the upper surface of the heat dissipation layer 30 to expose the heat dissipation layer 30. In addition, the heat dissipation hole shape of the present invention can also refer to the following Figure 2 , which further shows three heat dissipation holes 102, 104, and 106 with different depths.
[0036] Compared to Figure 1 The heat dissipation holes are 100, Figure 2 The heat dissipation hole 102 is deeper and penetrates the heat dissipation layer 30 and exposes the first adhesive layer 20. The bottom of the heat dissipation hole 102 is located on the upper surface of the first adhesive layer 20. Figure 2 The depth of the heat dissipation hole 104 is greater than Figure 1 The heat dissipation hole 104 is not as deep as the heat dissipation hole 102, but it does not penetrate the heat dissipation layer 30. As shown in the figure, the bottom of the heat dissipation hole 104 is located in the heat dissipation layer 30 and has not yet exposed the first adhesive layer 20. Compared with the prior art, these two methods can allow the heat accumulated in the heat dissipation layer 30 to be conducted to the outside more quickly through the path outside the second adhesive layer 40 and the protective layer 50 (i.e., the heat dissipation hole 102 or the heat dissipation hole 104).
[0037] As for Figure 2 The heat dissipation holes 106 in the Figure 1 The heat dissipation hole 106 is shallow, and its bottom position does not reach the heat dissipation layer 30 and does not expose the heat dissipation layer 30. On the other hand, it is lower than the lower surface of the protective layer 50 and is located in the second adhesive layer 40. Although the heat dissipation path provided by the heat dissipation hole 106 to the heat dissipation layer 30 still needs to pass through a small amount of the second adhesive layer 40, it can still improve the heat dissipation because it avoids passing through the protective layer 50 with poor thermal conductivity. However, in order to ensure the heat dissipation effect, the less the second adhesive layer 40 on the heat dissipation path, the better. Preferably, the depth of the heat dissipation hole 106 entering the second adhesive layer 40 can be greater than 1 / 3 of the thickness of the complete second adhesive layer 40, that is, the position of the bottom of the heat dissipation hole 106 is lower than 2 / 3 of the thickness of the complete second adhesive layer 40.
[0038] Please refer to Figure 3 As shown, it is another embodiment of the heat dissipation patch 10 of the present invention. Figure 1 Compared with the embodiment shown, the main difference is that the plurality of heat dissipation holes 100 in the heat dissipation patch 10 are also filled with heat dissipation glue 60 with a thermal conductivity of less than 100W / mk and a viscosity of less than 25,000Pa.s, thereby increasing the heat dissipation effect of the heat dissipation holes 100 as heat dissipation paths. Preferably, the heat dissipation glue 60 can be a thermosetting packaging glue composed of, for example, epoxy resin / silicone and oxidized metal powder (or a mixture of other metals and non-metals).
[0039] Please refer to Figure 4 As shown, it is another embodiment of the heat dissipation patch 10 of the present invention. Figure 1 and Figure 3 Compared with the embodiment shown, the main difference is that the plurality of heat dissipation holes 100 in the heat dissipation patch 10 are also filled with heat conductive metal 70, thereby increasing the heat dissipation effect of the heat dissipation holes 100 as heat dissipation paths. The heat conductive metal 70 can be, for example, copper paste, silver paste, or tin paste, etc., and can be filled into the heat dissipation holes 100 by screen printing, electroplating, or sputtering.
[0040] Please also refer to Figure 5 As shown, it is another embodiment of the heat dissipation patch 10 of the present invention. Figure 1 Compared with the embodiment shown, the main difference is that the heat dissipation patch 10 also has a heat diffusion layer 80, which is arranged between the heat dissipation layer 30 and the second adhesive layer 40. In this embodiment, the heat dissipation hole 100 extends downward from the upper surface of the protective layer 50 to the upper surface of the heat diffusion layer 80, thereby exposing the heat diffusion layer 80. The function of the heat diffusion layer 80 is to serve as a thermal interface material (Thermal interface material) to diffuse the heat accumulated in the heat dissipation layer 30 outward more quickly. Preferably, the thermal conductivity of the heat diffusion layer 80 in the horizontal direction (XY axis) is at least 50% higher than the thermal conductivity in the vertical direction (Z axis). The heat diffusion layer 80 can be, for example, graphene with a thickness of about 50μm.
[0041] Please refer to Figure 6 As shown, it is another embodiment of the heat dissipation patch 10 of the present invention. Figure 1 and Figure 5 Compared with the embodiment shown in FIG. 1 , the main difference is that the heat diffusion layer 85 is disposed at the bottom of the heat dissipation hole 100. The material of the heat diffusion layer 85 can be referred to as Figure 5 The heat diffusion layer 80 in the.
[0042] In addition, it is noted that Figure 5 The embodiment with heat diffusion layer 80 can also add Figure 3 Heat dissipation glue 60, such as Figure 7 Similarly, Figure 6 Embodiments with a heat diffusion layer 85 may also incorporate Figure 3 Heat dissipation glue 60, such as Figure 8 The embodiment shown.
[0043] at the same time, Figure 5 The embodiment with heat diffusion layer 80 can also add Figure 4 The heat conductive metal 70, such as Fig. 9 Similarly, Figure 6Embodiments with a heat diffusion layer 85 may also incorporate Figure 4 The heat conductive metal 70, such as Fig.10 The embodiment shown.
[0044] Different from Figures 1 to 10 is a side view, Fig.11 Other embodiments of the heat sink 100 are shown in top view. Fig.11 As shown, the heat sink 100 is roughly rectangular in shape, and the specific size can be adjusted according to actual conditions. Bending mainly occurs on the long side of the rectangle, so both sides of the long side (that is, where the short side is located) will be subject to obvious stress.
[0045] like Fig.11 As shown, the heat sink 100 has multiple Figure 1 The heat dissipation holes 100 (or Figure 2 The heat dissipation holes 102, 104, or 106) are arranged and form a linear array along the short side edge of the heat dissipation patch 100. The heat dissipation holes 100 have the effect of relieving stress because part of the structural material is removed. Preferably, the closer the distance D1 of the array formed by the heat dissipation holes 100 is to a short side edge of the heat dissipation patch 100, the more effectively the stress can be relieved. Preferably, the distance D1 does not exceed 6mm, for example, it can be 6mm, 3mm or 1mm. In another embodiment, the distance D1 of the heat dissipation holes 100 from a short side edge of the heat dissipation patch 100 is less than 25% of the distance D2 from the short side edge to another relatively short side edge, for example, the distance D1 can be 10% or 5% of the distance D2. It should also be noted that for the purpose of illustration, Fig.11 Only two rows of 5×1 heat dissipation holes 100 are shown in the figure. However, in other embodiments, there may be more heat dissipation holes 100 (or Figure 2 Heat dissipation holes 102, 104, or 106 in the embodiment.
[0046] Fig.12 The electronic device 3 of the present embodiment is shown, which includes a flexible circuit substrate 1, a chip 2 and a heat sink 10 disposed on the circuit board 1. For details of the heat sink 10, please refer to the above-mentioned Figures 1 to 11 The electronic device 3 may be, for example, a flat-panel display, a wearable device, a mobile phone, a tablet computer, a notebook computer, a car panel, or an industrial control panel, and the chip 2 may be, for example, a chip for driving an image display. Fig.12As shown, due to the small space inside the electronic device 3, the circuit board 1 must be bent during use. This part should be known to those skilled in the art and will not be described in detail here. In addition, in an embodiment not shown in the figure, the electronic device 3 does not need to be a finished product that can be immediately used by the end consumer, and as long as the chip 2 has been set on the circuit board 1, the electronic device 3 can also be a semi-finished product that needs to be processed later. It is also supplemented that in other embodiments not shown in the figure, the heat sink 10 can also be attached to the back side of the circuit board 1 (that is, the side where the chip 2 is not set), and this is not limited to this case.
[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the patent application of the present invention; any other equivalent changes or modifications that do not deviate from the spirit disclosed in the present invention should be included in the scope of the patent application.
[0048]
Explanation of symbols
[0049] Circuit Board 1
[0050] Wafer 2
[0051] Electronic device 3
[0052] Heat sink 10
[0053] The first adhesive layer 20
[0054] Heat dissipation layer 30
[0055] The second adhesive layer 40
[0056] Protective layer 50
[0057] Heat dissipation glue 60
[0058] Thermally conductive metal 70
[0059] Heat diffusion layers 80, 85
[0060] Heat dissipation holes 100, 102, 104, 106
[0061] Distance D1, D2.
Claims
1. A heat dissipation patch for bonding a circuit board, characterized in that: The heat sink contains: a first adhesive layer, the first adhesive layer being used to attach the circuit board; a heat dissipation layer, disposed above the first adhesive layer; A protective layer; being disposed above the heat dissipation layer; A plurality of heat dissipation holes are extended downward from the upper surface of the protection layer, and the bottoms of the plurality of heat dissipation holes are not lower than the upper surface of the first adhesive layer.
2. The heat sink according to claim 1, characterized in that: The bottoms of the plurality of heat dissipation holes are located in the heat dissipation layer.
3. The heat sink according to claim 1, wherein: The bottoms of the plurality of heat dissipation holes are not lower than the upper surface of the heat dissipation layer.
4. The heat sink according to claim 3, characterized in that: It also includes a heat diffusion layer, which is arranged between the heat dissipation layer and the protective layer, wherein the bottom of the plurality of heat dissipation holes is not lower than the upper surface of the heat diffusion layer, wherein the horizontal thermal conductivity of the heat diffusion layer is at least 50% higher than the vertical thermal conductivity.
5. The heat sink according to claim 1, wherein: The invention also comprises a heat diffusion layer, which is located at the bottom of the plurality of heat dissipation holes, wherein the heat conductivity of the heat diffusion layer in the horizontal direction is at least 50% higher than the heat conductivity in the vertical direction.
6. The heat sink according to claim 1, wherein: The invention also comprises a second adhesive layer, which is arranged between the heat dissipation layer and the protective layer, wherein the bottoms of the heat dissipation holes are lower than the lower surface of the protective layer.
7. The heat sink according to claim 6, characterized in that: The bottoms of the plurality of heat dissipation holes are lower than a position where the thickness of the second adhesive layer is 2 / 3.
8. The heat sink according to any one of claims 1 to 7, characterized in that: The plurality of heat dissipation holes are also filled with heat dissipation glue.
9. The heat sink according to any one of claims 1 to 7, characterized in that: The plurality of heat dissipation holes are also filled with a heat conductive metal.
10. The heat sink according to any one of claims 1 to 7, characterized in that: The diameter of the plurality of heat dissipation holes is at least 0.5 mm.
11. The heat sink according to any one of claims 1 to 7, characterized in that: The spacing between the plurality of heat dissipation holes is at least 1 mm.
12. The heat sink according to any one of claims 1 to 7, characterized in that: The distance between the plurality of heat dissipation holes and an edge of the heat dissipation patch does not exceed 6 mm.
13. The heat sink according to any one of claims 1 to 7, characterized in that: The heat dissipation patch has two opposite edges, and the distance between the plurality of heat dissipation holes and one of the two edges does not exceed 25% of the distance between the two edges.
14. A heat dissipation patch for adhering to a circuit board, characterized in that: The heat sink contains: a first adhesive layer, the first adhesive layer being used to attach the circuit board; a heat dissipation layer, disposed above the first adhesive layer; A protective layer; being disposed above the heat dissipation layer; A plurality of heat dissipation holes extending downward from the upper surface of the protective layer; The heat dissipation patch has two opposite edges, and the distance between the plurality of heat dissipation holes and one of the two edges is less than 25% of the distance between the two edges.
15. A circuit board, characterized in that: Include: a substrate having a circuit layer; and The heat sink as claimed in claim 1 or 14, wherein the heat sink is attached to the substrate.
16. An electronic device, characterized in that: Include: The circuit board as claimed in claim 15; and A chip is disposed on the circuit board.