Electronic packaging material and preparation method and application thereof

Abstract

The invention relates to an electronic packaging material which comprises a porous diamond heat sink sheet and a plurality of heat-conducting prepregs, and the porous diamond heat sink sheet is clamped between the heat-conducting prepregs. The electronic packaging material not only can keep the hot-pressing processability and the adhesive force between the electronic packaging material and the copper foil of the same type of products, but also can remarkably improve the heat-conducting property of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of high thermal conductivity materials, and particularly to an electronic packaging material, a preparation method thereof, and an application thereof. Background Art

[0002] With the development of electronic devices towards high power density, high frequency, and miniaturization, their thermal management capabilities directly determine the performance, reliability, and lifespan of the devices. The commonly used heat dissipation materials in the PCB field are polymer-based composite materials, and currently, most of them are composite materials of epoxy resin and ceramic-based thermal conductive particles (such as boron nitride, aluminum nitride, or alumina), with a thermal conductivity generally in the range of 1 - 3 W / mK. The heat dissipation performance of the composite material is directly related to the self-heat dissipation performance and filling amount of the thermal conductive filler. The best thermally conductive substance in nature is diamond, but the chemical inertness of diamond makes it difficult to modify, with poor compatibility with organic polymer resins, a low filling amount. At the same time, the high hardness of diamond will cause equipment wear and introduce impurities during the stirring and dispersion process.

[0003] Therefore, there is an urgent need to develop an electronic packaging material that can utilize the good thermal conductivity of diamond while solving the above drawbacks. Summary of the Invention

[0004] In view of the above problems, the present invention provides an electronic packaging material that can retain the hot pressing processability and adhesion to copper foil of existing products of the same type while significantly improving the thermal conductivity of the material.

[0005] To achieve the above object, the present invention provides an electronic packaging material, including a porous diamond heat sink sheet and a plurality of thermally conductive prepregs, and the porous diamond heat sink sheet is sandwiched between the thermally conductive prepregs.

[0006] In the research process, the inventor found that if diamond is directly used and sandwiched and pressed, there is a lack of bonding force with other layer structures and cracking is likely to occur. Therefore, the inventor proposed to provide a number of small holes in the diamond heat sink sheet, so that the resin in the thermally conductive semi-cured sheet can flow through the small holes. Thus, in the curing step of hot pressing at high temperature, they can be tightly bonded together, and there will be no air gap that negatively affects the thermal conductivity and insulation performance. Furthermore, the prepared sandwich structure "thermally conductive semi-cured sheet + porous diamond heat sink sheet + thermally conductive semi-cured sheet" not only has better thermal conductivity, but also the porous structure ensures the flow of the resin and does not affect the insulation of the material after curing. At the same time, the epoxy resin-based thermally conductive paste semi-cured on the upper and lower layers of the electronic packaging material retains the processability of hot pressing and the adhesion to the copper foil. Moreover, under the above unique structural design, the area of the electronic packaging material can be customized at will according to the product requirements. When it is applied to PCB packaging, the process flow does not need special treatment, and only the traditional lamination process of processing is still required to obtain high thermal conductivity and high insulation performance.

[0007] In one embodiment, the porous diamond heat sink sheet has a number of through holes, and the through holes are arranged along the thickness direction of the diamond heat sink sheet.

[0008] In one embodiment, the aperture of the through hole is 10 - 20 μm, and the thickness of the porous diamond heat sink sheet is 0.3 - 0.5 mm.

[0009] In one embodiment, every 1 mm 2 10 - 100 of the through holes are provided on one side surface of the porous diamond heat sink sheet.

[0010] In one embodiment, the through holes are evenly distributed on the porous diamond heat sink sheet.

[0011] In one embodiment, the through holes are formed by laser drilling.

[0012] In one embodiment, the raw materials of the thermally conductive semi-cured sheet include epoxy resin, thermally conductive filler, and curing agent; the mass percentages of the epoxy resin, thermally conductive filler, and curing agent are (28% - 40%):(30% - 45%):(25% - 30%).

[0013] In one embodiment, the epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenolic epoxy resin, and alicyclic epoxy resin;

[0014] The thermally conductive filler includes at least one of aluminum nitride, boron nitride, and alumina.

[0015] In one embodiment, the epoxy resin includes at least one of E-51, E-44, and E-20.

[0016] In one embodiment, the aluminum nitride is spherical aluminum nitride, the boron nitride is spherical boron nitride, and the alumina is spherical alumina.

[0017] In one embodiment, the particle size D of the thermal conductive filler 50 = 30 - 60 μm.

[0018] In one embodiment, the preparation raw materials further include a curing agent and a solvent, and the mass ratio of the epoxy resin, the curing agent, and the solvent is (8 - 12):(6 - 10):(3 - 7).

[0019] In one embodiment, the curing agent includes at least one of an acid anhydride-based curing agent, a phenolic-based curing agent, a polyamide-based curing agent, an active ester-based curing agent, a latent curing agent, and an amine-based curing agent that can be used for curing the epoxy resin.

[0020] In one embodiment, the solvent includes at least one of acetone, methyl ethyl ketone, toluene, and DMF.

[0021] The present invention also provides a preparation method of the electronic packaging material, including the following steps:

[0022] Preparing a thermally conductive semi-cured sheet: Dissolving and mixing the raw materials of the thermally conductive semi-cured sheet with a solvent to obtain a thermally conductive slurry, coating the thermally conductive slurry on a release film by a wet method to form a thermally conductive slurry layer, and drying to a semi-cured state to obtain the thermally conductive semi-cured sheet;

[0023] Preparing the electronic packaging material: Removing the release film, sandwiching the porous diamond heat sink sheet between the thermally conductive semi-cured sheets, and performing hot pressing at a high temperature to obtain the electronic packaging material.

[0024] The above preparation method is simple and effective. Under the above unique structural design, this preparation method does not need to be specially improved, and the electronic packaging material can be obtained by using conventional coating and hot pressing at a high temperature.

[0025] In one embodiment, in the step of preparing the thermally conductive semi-cured sheet, the solvent includes at least one of acetone, methyl ethyl ketone, toluene, and DMF.

[0026] In one embodiment, the thickness of the thermally conductive slurry layer is 100 - 160 μm; the release film includes at least one of polyethylene (PE), polyester (PET), and polypropylene (PP).

[0027] The present invention also provides an application of the electronic packaging material in PCB products.

[0028] The present invention also provides a packaging material for a PCB, including the electronic packaging material.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] An electronic packaging material, a preparation method and an application thereof according to the present invention. This electronic packaging material can not only retain the hot pressing processability and adhesion to copper foil of existing products of the same type, but also significantly improve the thermal conductivity of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic structural diagram of the electronic packaging material of the present invention, where 1 is a thermally conductive semi-cured sheet and 2 is a porous diamond heat sink sheet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0033] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be intermediate elements at the same time.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0035] Definition:

[0036] High thermal conductivity material: In the present invention, it refers to a material with a thermal conductivity ≥ 2 W / m·K.

[0037] Source:

[0038] Thermal conductive filler: Tianyuan Aviation Materials boron nitride h-BNF (D 50 = 30 μm), Guangdong Yuxing alumina XYS-40 (D 50 [[ID=(39]]= 45 μm), Tokuyama H-T aluminum nitride from Japan (D 50 = 60 μm);

[0039] Curing agent: The curing agents commonly used in the art can be adopted, as long as they have the function of curing the resin, and there is no special limitation. For example, for the curing of epoxy resin, anhydride-based curing agents, phenolic-based curing agents, polyamide-based curing agents, active ester-based curing agents, latent curing agents or amine-based curing agents, etc. can be selected.

[0040] Example 1

[0041] I. A preparation method of an electronic packaging material.

[0042] 1. Prepare a thermally conductive semi-cured sheet.

[0043] According to the designed experimental formula, weigh a certain amount of resin, curing agent, filler and solvent, blend and stir to obtain a uniform slurry, wet-coat an epoxy resin-based thermally conductive slurry on a release film, and transfer it to an oven to dry to a semi-cured state. The thickness of the thermally conductive slurry is controlled at 100 - 160 μm.

[0044] 2. Prepare a porous diamond heat sink sheet.

[0045] The heat sink sheet is provided with a plurality of through holes, and the through holes are formed by drilling through in the thickness direction; preferably, the number of through holes relative to the area of the upper surface (or lower surface) of the heat sink sheet is: 10 - 100 pieces / mm 2 ; when the number of drilled through holes is more than 1, preferably, they are evenly distributed on the heat sink sheet; the way of drilling through is laser drilling, and by adjusting the spot diameter and energy of the laser, a through hole structure with unequal areas of the upper and lower hole openings can be obtained.

[0046] 3. Prepare an electronic packaging material.

[0047] Remove the release film, sandwich the porous diamond heat sink sheet between two thermally conductive semi-cured sheets, and perform hot pressing at high temperature to obtain an electronic packaging material, and the structure is as Figure 1 shown.

[0048] II. In this example, an electronic packaging material is specifically prepared by using the method in the above "I. A preparation method of an electronic packaging material".

[0049] 1. Prepare a thermally conductive semi-cured sheet.

[0050] Mix 100 parts by mass of E-51 epoxy resin, 80 parts by mass of methyltetrahydrophthalic anhydride curing agent, 70 parts by mass of alumina (thermal conductive filler), 30 parts by mass of boron nitride (thermal conductive filler), and 50 parts by mass of acetone (solvent) to obtain an epoxy resin thermal conductive paste. Then, prepare a thermal conductive semi-cured sheet with an area of 6 mm × 6 mm and a thickness of 120 μm according to the preparation method of the above thermal conductive semi-cured sheet. Since the solvent is basically removed during the drying process, there is very little solvent in the prepared thermal conductive semi-cured sheet. Therefore, the thermal conductive semi-cured sheet is composed of epoxy resin, curing agent, and thermal conductive filler. In the thermal conductive semi-cured sheet of this example, the mass percentages of epoxy resin, curing agent, and thermal conductive filler are 35.71%: 28.57%: 35.71%.

[0051] 2. Prepare a porous diamond heat sink sheet.

[0052] By adjusting the laser spot diameter and energy, 1000 holes are drilled through the 0.3 mm thick diamond heat sink sheet (the surface size of the heat sink sheet is 5 mm × 5 mm) along the thickness direction. The 1000 holes are evenly distributed on the diamond heat sink sheet in a 25×40 matrix, and the diameter of a single hole is 20 μm.

[0053] 3. Prepare an electronic packaging material.

[0054] After removing the release film, place the porous diamond heat sink sheet between two thermal conductive semi-cured sheets and prepare the electronic packaging material by hot pressing at high temperature.

[0055] Example 2

[0056] A preparation method of an electronic packaging material.

[0057] 1. Prepare a thermal conductive semi-cured sheet.

[0058] Mix 100 parts by mass of E-44 epoxy resin, 80 parts by mass of methylhexahydrophthalic anhydride curing agent, 70 parts by mass of alumina (thermal conductive filler), 70 parts by mass of boron nitride (thermal conductive filler), and 50 parts by mass of acetone (solvent) to obtain an epoxy resin thermal conductive paste. Then, prepare a thermal conductive semi-cured sheet with an area of 6 mm × 6 mm and a thickness of 120 μm according to the preparation method of the thermal conductive semi-cured sheet in Example 1. In the thermal conductive semi-cured sheet of this example, the mass percentages of epoxy resin, curing agent, and thermal conductive filler are 31.25%: 25%: 43.75%.

[0059] 2. Prepare a porous diamond heat sink sheet.

[0060] By adjusting the laser spot diameter and energy, 800 holes are drilled through the 0.3-mm-thick diamond heat sink (the surface size of the diamond heat sink is 5 mm × 5 mm) along the thickness direction. The 800 holes are evenly distributed in a 20×40 matrix on the diamond heat sink, and the aperture of a single hole is 20 μm.

[0061] 3. Prepare the electronic packaging material.

[0062] After removing the release film, place the porous diamond heat sink between two thermally conductive prepregs and prepare the electronic packaging material by high-temperature hot pressing.

[0063] Example 3

[0064] A preparation method of an electronic packaging material.

[0065] 1. Prepare the thermally conductive prepreg.

[0066] Mix 100 parts by mass of E-44 epoxy resin, 80 parts by mass of methylhexahydrophthalic anhydride curing agent, 70 parts by mass of alumina (thermal conductive filler), 30 parts by mass of aluminum nitride (thermal conductive filler), and 50 parts by mass of acetone (solvent) as the solvent to obtain an epoxy resin thermal conductive paste. Then, prepare a thermally conductive prepreg with an area of 6 mm × 6 mm and a thickness of 120 μm according to the preparation method of the thermally conductive prepreg in Example 1. In the thermally conductive prepreg of this example, the mass percentages of the epoxy resin, curing agent, and thermal conductive filler are 35.71%: 28.57%: 35.71%.

[0067] 2. Prepare the porous diamond heat sink.

[0068] By adjusting the laser spot diameter and energy, 800 holes are drilled through the 0.3-mm-thick diamond heat sink (the surface size of the diamond heat sink is 5 mm × 5 mm) along the thickness direction. The 800 holes are evenly distributed in a 20×40 matrix on the heat sink, and the aperture of a single hole is 20 μm.

[0069] 3. Prepare the electronic packaging material.

[0070] After removing the release film, place the porous diamond heat sink between two thermally conductive prepregs and prepare the electronic packaging material by high-temperature hot pressing.

[0071] Example 4

[0072] A preparation method of an electronic packaging material.

[0073] 1. Prepare the thermally conductive prepreg.

[0074] Mix 100 parts by mass of E-44 epoxy resin, 80 parts by mass of methylhexahydrophthalic anhydride curing agent, 70 parts by mass of aluminum nitride (thermal conductive filler), 30 parts by mass of alumina (thermal conductive filler), and 50 parts by mass of acetone (solvent) to obtain an epoxy resin thermal conductive paste. Then, prepare a thermal conductive semi-cured sheet with an area of 6 mm × 6 mm and a thickness of 120 μm according to the preparation method of the thermal conductive semi-cured sheet in Example 1. In the thermal conductive semi-cured sheet of this example, the mass percentages of epoxy resin, curing agent, and thermal conductive filler are 31.25%: 25%: 43.75%.

[0075] 2. Prepare a porous diamond heat sink sheet.

[0076] By adjusting the laser spot diameter and energy, drill 1200 holes through the 0.3-mm-thick diamond heat sink sheet (the surface size of the diamond heat sink sheet is 5 mm × 5 mm) along the thickness direction. 800 holes are evenly distributed on the diamond heat sink sheet in a 30×40 matrix, and the aperture of a single hole is 20 μm.

[0077] 3. Prepare an electronic packaging material.

[0078] After removing the release film, place the porous diamond heat sink sheet between two thermal conductive semi-cured sheets and prepare the electronic packaging material by high-temperature hot pressing.

[0079] Example 5

[0080] A preparation method of an electronic packaging material.

[0081] 1. Prepare a thermal conductive semi-cured sheet.

[0082] Mix 100 parts by mass of E-44 epoxy resin, 80 parts by mass of methylhexahydrophthalic anhydride curing agent, 70 parts by mass of aluminum nitride (thermal conductive filler), 30 parts by mass of boron nitride (thermal conductive filler), and 50 parts by mass of acetone (solvent) to obtain an epoxy resin thermal conductive paste. Then, prepare a thermal conductive semi-cured sheet with an area of 6 mm × 6 mm and a thickness of 120 μm according to the preparation method of the thermal conductive semi-cured sheet in Example 1.

[0083] 2. Prepare a porous diamond heat sink sheet.

[0084] By adjusting the laser spot diameter and energy, drill 1200 holes through the 0.3-mm-thick diamond heat sink sheet (the surface size of the diamond heat sink sheet is 5 mm × 5 mm) along the thickness direction. 800 holes are evenly distributed on the diamond heat sink sheet in a 30×40 matrix, and the aperture of a single hole is 20 μm. In the thermal conductive semi-cured sheet of this example, the mass percentages of epoxy resin, curing agent, and thermal conductive filler are 35.71%: 28.57%: 35.71%.

[0085] 3. Preparation of electronic packaging materials.

[0086] After removing the release film, place the porous diamond heat sink between two thermally conductive prepregs and prepare the electronic packaging material by hot pressing at high temperature.

[0087] Comparative Example 1

[0088] It is basically the same as the preparation method of Example 1, except that: no diamond heat sink is added in the middle.

[0089] Comparative Example 2

[0090] It is basically the same as the preparation method of Example 2, except that: no diamond heat sink is added in the middle.

[0091] Comparative Example 3

[0092] It is basically the same as the preparation method of Example 3, except that: no diamond heat sink is added in the middle.

[0093] Comparative Example 4

[0094] It is basically the same as the preparation method of Example 4, except that: no diamond heat sink is added in the middle.

[0095] Comparative Example 5

[0096] It is basically the same as the preparation method of Example 5, except that: no diamond heat sink is added in the middle.

[0097] Experimental Example

[0098] Verify the performance of the electronic packaging materials prepared in each example and comparative example.

[0099] 1. Thermal conductivity test.

[0100] Use the TPS2200 thermal conductivity meter of Hot Disk Company in Sweden to test the thermal conductivity of the examples and comparative examples, and select the polyimide-coated 7577 probe.

[0101] 2. Insulation strength test.

[0102] Use the Taiwan Chroma 19073 in Taiwan Province of China to test the insulation strength of the implementation cases and comparison cases.

[0103] The test results of the sample performance are shown in Table 1 below.

[0104] Table 1 Test results of sample performance

[0105]

[0106]

[0107] The test results show that the present invention combines an epoxy resin-based thermally conductive semi-cured sheet and a porous diamond heat sink. By comparing the examples and the comparative examples, the thermal conductivity of the examples is doubled, and the insulation performance is also improved to a certain extent. This indicates that adding a porous diamond heat sink between two epoxy resin-based thermally conductive semi-cured sheets not only improves the thermal conductivity of the material, with the thermal conductive paste fully filling the holes on the heat sink, but also increases the insulation performance of the material. At the same time, the epoxy resin semi-cured sheet of the present invention also conforms to the lamination process of the PCB.

[0108] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0109] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. An electronic packaging material, characterized in that, It includes a porous diamond heat sink sheet and a number of thermally conductive semi-cured sheets, and the porous diamond heat sink sheet is sandwiched between the thermally conductive semi-cured sheets.

2. The electronic packaging material according to claim 1, characterized in that, The porous diamond heat sink sheet has a number of through holes, and the through holes are arranged along the thickness direction of the diamond heat sink sheet.

3. The electronic packaging material according to claim 2, wherein The aperture of the through hole is 10 - 20 μm, and the thickness of the porous diamond heat sink sheet is 0.3 - 0.5 mm.

4. The electronic packaging material according to claim 1, wherein The raw materials of the thermally conductive semi-cured sheet include epoxy resin, thermally conductive filler, and curing agent; the mass percentages of the epoxy resin, thermally conductive filler, and curing agent are (28% - 40%):(30% - 45%):(25% - 30%).

5. The electronic packaging material according to claim 4, wherein The epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenolic epoxy resin, and alicyclic epoxy resin; The thermally conductive filler includes at least one of aluminum nitride, boron nitride, and aluminum oxide.

6. The electronic packaging material according to claim 5, wherein The aluminum nitride is spherical aluminum nitride, the boron nitride is spherical boron nitride, and the aluminum oxide is spherical aluminum oxide.

7. The preparation method of the electronic packaging material according to any one of claims 1-6, characterized in that, It includes the following steps: Preparing the thermally conductive semi-cured sheet: Dissolving and mixing the raw materials of the thermally conductive semi-cured sheet with a solvent to obtain a thermally conductive slurry, coating the thermally conductive slurry on a release film by a wet method to form a thermally conductive slurry layer, and drying it to a semi-cured state to obtain the thermally conductive semi-cured sheet; Preparing the electronic packaging material: Removing the release film, sandwiching the porous diamond heat sink sheet between the thermally conductive semi-cured sheets, and performing hot pressing at high temperature to obtain the electronic packaging material.

8. The preparation method according to claim 7, characterized in that, The thickness of the thermally conductive slurry layer is 100 - 160 μm; the release film includes at least one of polyethylene (PE), polyester (PET), and polypropylene (PP).

9. Application of the electronic packaging material according to any one of claims 1 - 6 in a PCB product.

10. A packaging material for a PCB, characterized in that, It includes the electronic packaging material according to any one of claims 1 - 6.

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