High-thermal-conductivity substrate

Abstract

The invention discloses a halogen-free environment-friendly substrate with high thermal conductivity. The silicon carbide composite material comprises the following preparation raw materials in parts by weight: 30-70 parts of silicon carbide powder, 5-15 parts of o-cresol formaldehyde epoxy resin, 5-15 parts of phosphorus-containing phenolic resin, 3-15 parts of biphenyl epoxy resin, 2-13 parts of phenol novolac epoxy resin, 3-8 parts of linear phenol formaldehyde resin, 1-5 parts of an amine chain extender, 5-20 parts of a first organic solvent and 5-20 parts of a second organic solvent, a heat conduction channel is formed by utilizing a regular crystal structure of silicon carbide, relatively high heat conductivity is realized, a component system is reasonably researched, developed and designed, other properties are comprehensively improved, particularly, good electrical insulation performance is achieved, and the glass transition temperature and the heat resistance are high; it is ensured that safety problems such as electric leakage can not occur while efficient heat dissipation of the electronic equipment can be assisted, and the electronic equipment has the advantage of being high in performance and can meet the development trend of equipment miniaturization.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic components, and particularly relates to a high thermal conductivity substrate. Background Art

[0002] At present, with the continuous development of electronic technology, the integration and power density of electronic components continue to increase, making the heat dissipation problem a key factor restricting the performance and reliability of electronic devices.

[0003] For existing electronic device substrates, considering factors such as their processing, the inner layer usually uses a substrate made of glass fiber + epoxy resin as the matrix and the outer layer uses copper foil for high-temperature lamination. The thermal conductivity of these materials is relatively low, only about 0.4 - 0.8 W / (m·K), resulting in the inability to dissipate heat in a timely and effective manner when electronic components operate at high power. This not only reduces the working efficiency of electronic components but also has a greater impact on the service life of electronic components mounted on the substrate, and even causes equipment failures.

[0004] Traditional heat dissipation solutions, such as adding heat sinks, fans, etc., often increase the volume and weight of the equipment, which is not conducive to the miniaturization of the equipment.

[0005] Traditional thermal interface materials (such as thermal conductive adhesives, thermal conductive silica gels, thermal conductive gels, etc.) have relatively poor heat transfer performance. Therefore, new thermal conductive materials, such as graphite and liquid metal, have also been developed in this field. However, graphite sheets are brittle and have a low degree of fit with the heat-generating surface of electronic components, and liquid metal is difficult to apply, and there are problems such as easy overflow causing short circuits in the circuit.

[0006] To solve the above problems, some substrate structures that focus on improving thermal conductivity have emerged in this field. For example, in a through-hole conductive FPC board + ceramic board structure, the heat conduction path is a multi-layer structure such as ceramic board → tin foil → IMC layer → tin + soft board via copper → conductive adhesive → steel sheet. There is also the technical solution "a multi-layer thick film ceramic-based circuit board" disclosed in the patent document with the publication number CN113225901B. Although this type of high thermal conductivity packaging substrate structure improves the thermal conductivity to a certain extent, the heat conduction path is still relatively complex, and heat is easily blocked during the transfer process, resulting in low heat dissipation efficiency, and there are problems such as small heat conduction area and unsatisfactory heat dissipation effect. Summary of the Invention

[0007] In view of the problems in the related art, the present invention provides a high thermal conductivity substrate to overcome the above technical problems existing in the related art.

[0008] The technical solution of the present invention is realized as follows:

[0009] A high thermal conductivity substrate comprises the following raw materials for preparation in parts by weight:

[0010] 30 - 70 parts of silicon carbide powder, 5 - 15 parts of o-cresol novolac epoxy resin, 5 - 15 parts of phosphorus-containing phenolic resin, 3 - 15 parts of biphenyl-type epoxy resin, 2 - 13 parts of phenol-type phenolic epoxy resin, 3 - 8 parts of linear phenol formaldehyde resin, 1 - 5 parts of amine chain extender, 5 - 20 parts of the first organic solvent and 5 - 20 parts of the second organic solvent.

[0011] In the present invention, by utilizing the regular crystal structure of silicon carbide to form a heat conduction channel, a relatively high heat conduction rate is achieved, and the in-plane thermal conductivity coefficient is ≥ 2.59 W / m·K. Through reasonable research and development design of the component system, other various properties are comprehensively improved. In particular: First, the present invention has good electrical insulation performance. Under the condition of a thickness of only 0.12 - 0.13 mm, it has a breakdown voltage resistance performance of more than 8 kV, and the leakage current is less than 1 μA, ensuring that while the present invention can assist electronic devices in efficient heat dissipation, no safety problems such as electric leakage will occur. The characteristics of being thin but having high performance can meet the development trend of equipment miniaturization. Second, the present invention has a high glass transition temperature, and the glass transition temperature is ≥ 170 °C, making it more stable during use. Third, the present invention is a halogen-free environmentally friendly material, and at the same time has high heat resistance, and can meet the use requirements of various environments.

[0012] Preferably, the silicon carbide powder is α-type silicon carbide, and the silicon carbide powder is P-type doped; the particle size range of the silicon carbide powder is 5 - 10 μm, and a micro-nano vertical structure P-type alpha-phase silicon carbide is adopted, which has a regular crystal structure by itself, and the special vertical structure can form an optimal heat conduction channel during heat conduction.

[0013] Preferably, the phenol-type phenolic epoxy resin is high-heat-resistant phenol special epoxy resin 638, which can increase the glass transition temperature of the present invention and endow the present invention with good heat resistance while taking into account the heat conduction performance;

[0014] The linear phenol formaldehyde resin is linear phenol formaldehyde PN 8020, which has high bonding strength and toughness, also has good anti-peeling ability and temperature resistance, and at the same time plays the role of a curing agent in the component system of the present invention;

[0015] The phosphorus-containing phenolic resin is high-flame-retardant phosphorus-containing phenolic 950, which has a flame-retardant effect and plays a synergistic effect of a curing agent in the component system;

[0016] The biphenyl-type epoxy resin is naphthalene ring biphenyl epoxy resin NC3000H, which has good bonding performance, can further improve the composite stability with the main component silicon carbide, and at the same time has excellent heat resistance and low moisture absorption, and also has flame-retardant characteristics and high toughness.

[0017] Preferably, the first organic solvent is propylene glycol methyl ether (PM), and the second organic solvent is methyl ethyl ketone (MEK), which function as a dispersing and dissolving agent and an auxiliary agent.

[0018] Preferably, the o-cresol novolac epoxy resin is o-cresol novolac special epoxy resin 704.

[0019] Preferably, the amine chain extender is 3,3'-diethyl-4,4'-diaminodiphenylmethane (H256). As a chain extender for PM and o-cresol novolac special epoxy resin 704, the amino groups at both ends can form a network structure with o-cresol novolac special epoxy resin 704 under certain temperature and time conditions, thereby having good adhesiveness and firmly bonding the main component silicon carbide.

[0020] Preferably, the preparation of the high thermal conductivity substrate includes the following steps:

[0021] (1) Mix a preset weight portion of o-cresol novolac epoxy resin, amine chain extender, and the first organic solvent, and stir and react at 60 - 100 °C with a rotation speed of 300 - 500 r / min for 1 - 4 h to form a slurry.

[0022] (2) After the slurry is cooled to room temperature, take a small amount for reactivity testing. If the viscosity-average molecular weight Mw is 200 - 300 and the Tg is 180 °C, it is qualified and proceed to the next step.

[0023] (3) Add a preset weight portion of linear phenol formaldehyde resin and the second organic solvent to the slurry obtained in step (1) and stir and react at a rotation speed of 100 - 150 r / min. After fully dissolving and mixing, maintain the reaction for 1 - 2 h.

[0024] (4) Continue to add a preset weight portion of biphenyl-type epoxy resin and stir and react at a rotation speed of 100 - 150 r / min. After fully dissolving and mixing, maintain the reaction for 1.5 - 2.5 h.

[0025] (5) Continue to add a preset weight portion of phenol-type phenolic epoxy resin and phosphorus-containing phenolic resin and stir and react at a rotation speed of 200 - 300 r / min, maintaining the reaction for 0.8 - 1.2 h.

[0026] (6) Continue to add a preset weight portion of silicon carbide powder and stir and mix and react at a speed of 300 - 450 r / min for 3.5 - 4.5 h. If the viscosity is 300 - 500 s, it is qualified, and a thermal conductive coating is prepared.

[0027] (7) Prepare fiberglass cloth, completely immerse the fiberglass cloth in the thermal conductive coating. The weight of the fiberglass cloth is 15 - 45 wt% of the thermal conductive coating, then press and finally dry and cool to cure to make a high thermal conductivity substrate with a fiberglass cloth layer and a thermal conductive layer.

[0028] Preferably, in step (7), the glass fiber cloth is completely immersed in the thermal conductive coating for at least 3 min to allow the thermal conductive coating to fully infiltrate and penetrate the woven grid structure of the glass fiber cloth.

[0029] Preferably, in step (7), the glass fiber cloth is an electronic-grade glass fiber cloth; the electronic-grade glass fiber cloth can be one of NE-glass fiber cloth, E-glass fiber cloth, and flat E-glass fiber cloth, and NE-glass fiber cloth is preferred.

[0030] Preferably, the weaving specification of the electronic-grade glass fiber cloth is 106 or 1080, and the parameters are shown in the following table.

[0031]

[0032] Preferably, conductive copper foil is laminated on one or both outer surfaces of the high thermal conductivity substrate, and the conductive copper foil has a thickness of 9-75 μm;

[0033] The lamination operation is as follows: cover the conductive copper foil on the outer surface of the high thermal conductivity substrate and laminate at a lamination temperature of 150-280 °C for 2-4 h. Detailed implementation manners

[0034] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0035] Embodiment 1

[0036] A high thermal conductivity substrate comprises the following raw materials for preparation by weight:

[0037] 45 kg of silicon carbide powder;

[0038] 5 kg of o-cresol novolac epoxy resin (o-cresol novolac special epoxy resin 704);

[0039] 5 kg of phosphorus-containing phenolic resin (high flame-retardant phosphorus-containing phenolic 950);

[0040] 5 kg of biphenyl-type epoxy resin (naphthalene ring biphenyl epoxy resin NC3000H);

[0041] 5 kg of phenol-type phenolic epoxy resin (high heat-resistant phenol special epoxy resin 638);

[0042] 3 kg of linear phenol formaldehyde resin (linear phenol formaldehyde PN 8020);

[0043] 1 kg of amine chain extender (3,3'-diethyl-4,4'-diaminodiphenylmethane H256);

[0044] 10 kg of the first organic solvent (propylene glycol methyl ether PM);

[0045] 10 kg of the second organic solvent (methyl ethyl ketone MEK).

[0046] The silicon carbide powder is α-type silicon carbide, P-type doped, with a particle size range of 5 - 10 μm.

[0047] The preparation method includes the following steps:

[0048] (1) Put the preset weights of o-cresol novolac epoxy resin, amine chain extender, and the first organic solvent into a stirring reaction kettle and mix them together. Stir and react at 60 °C with a rotation speed of 300 r / min for 1 h to make a slurry.

[0049] (2) After the slurry is cooled to room temperature, take a small amount for reactivity testing. If the viscosity-average molecular weight Mw is 200 - 300 and the Tg is 180 °C, it is qualified and proceed to the next step.

[0050] (3) Add the preset weights of linear phenol formaldehyde resin and the second organic solvent to the slurry prepared in step (1) and stir and react at a rotation speed of 100 r / min. After fully dissolving and mixing, maintain the reaction for 1 h.

[0051] (4) Continue to add the preset weight of biphenyl-type epoxy resin and stir and react at a rotation speed of 100 r / min. After fully dissolving and mixing, maintain the reaction for 1.5 h.

[0052] (5) Continue to add the preset weights of phenol-type phenolic epoxy resin and phosphorus-containing phenolic resin and stir and react at a rotation speed of 200 r / min, maintaining the reaction for 0.8 h.

[0053] (6) Continue to add the preset weight of silicon carbide powder and stir and mix and react at a speed of 300 r / min for 3.5 hours. If the viscosity is 300 - 500 s, it is qualified, and a thermal conductive coating is prepared.

[0054] (7) Prepare fiberglass cloth, completely immerse (NE-fiberglass cloth) in the thermal conductive coating for 3 min. The weight of the fiberglass cloth is 30 wt% of the thermal conductive coating, then press and finally dry and cool to cure to make a high thermal conductive substrate with a fiberglass cloth layer and a thermal conductive layer.

[0055] The weaving specification of the electronic-grade fiberglass cloth adopts 106 or 1080, and the parameters are shown in the following table.

[0056]

[0057] (8) Prepare a conductive copper foil with a thickness of 30 μm, cover the outer plate surface of the high thermal conductivity substrate with the conductive copper foil, and press it at a pressing temperature of 150 °C for 2 h.

[0058] Example 2

[0059] A high thermal conductivity substrate, comprising preparation raw materials with the following weights:

[0060] 50 kg of silicon carbide powder;

[0061] 10 kg of o-cresol novolac epoxy resin (o-cresol novolac special epoxy resin 704);

[0062] 10 kg of phosphorus-containing phenolic resin (high flame-retardant phosphorus-containing phenolic 950);

[0063] 10 kg of biphenyl-type epoxy resin (naphthalene ring biphenyl epoxy resin NC3000H);

[0064] 8 kg of phenol novolac epoxy resin (high heat-resistant phenol special epoxy resin 638);

[0065] 5 kg of linear phenol formaldehyde resin (linear phenol formaldehyde PN 8020);

[0066] 3 kg of amine chain extender (3,3'-diethyl 4,4'-diaminodiphenylmethane H256);

[0067] 15 kg of the first organic solvent (propylene glycol methyl ether PM);

[0068] 15 kg of the second organic solvent (methyl ethyl ketone MEK).

[0069] The silicon carbide powder is α-type silicon carbide, P-type doped, and the particle size range is 5-10 μm.

[0070] The preparation method includes the following steps:

[0071] (1) Put the preset weights of o-cresol novolac epoxy resin, amine chain extender and the first organic solvent into a stirring reaction kettle and mix them together, stir and react at 80 °C, the rotation speed is 400 r / min, and the reaction duration is 2.5 h to make a slurry.

[0072] (2) After the slurry is cooled to room temperature, take a small amount for reactivity testing. If the viscosity-average molecular weight Mw is 200-300 and the Tg is 180 °C, it is qualified and proceed to the next step.

[0073] (3) Add the preset weights of linear phenol formaldehyde resin and the second organic solvent to the slurry prepared in step (1) and stir and react, the rotation speed is 125 r / min. After fully dissolving and mixing, keep reacting for 1.5 h.

[0074] (4) Continuously add a preset weight of biphenyl-type epoxy resin and stir for reaction at a rotation speed of 125 r / min. After complete dissolution and mixing, maintain the reaction for 2.0 h.

[0075] (5) Continuously add a preset weight of phenol-type phenolic epoxy resin and phosphorus-containing phenolic resin and stir for reaction at a rotation speed of 250 r / min. Maintain the reaction for 1.0 h.

[0076] (6) Continuously add a preset weight of silicon carbide powder and stir and mix for reaction at a speed of 400 r / min for 4.0 hours. If the viscosity is 300 - 500 s, it is qualified, and a thermal conductive coating is prepared.

[0077] (7) Prepare fiberglass cloth, completely immerse (E - fiberglass cloth) in the thermal conductive coating for 4 min. The weight of the fiberglass cloth is 30 wt% of the thermal conductive coating, then press and laminate, and finally dry and cool for curing to make a high - thermal - conductivity substrate with a fiberglass cloth layer and a thermal conductive layer.

[0078] The parameters of the electronic - grade fiberglass cloth are shown in the following table.

[0079]

[0080] (8) Prepare a conductive copper foil with a thickness of 30 μm, cover the outer plate surface of the high - thermal - conductivity substrate with the conductive copper foil, and press and laminate at a pressing temperature of 200 °C for 3 h.

[0081] Example 3

[0082] A high - thermal - conductivity substrate comprises the following raw materials by weight:

[0083] 55 kg of silicon carbide powder;

[0084] 15 kg of o - cresol novolac epoxy resin (o - cresol novolac special epoxy resin 704);

[0085] 15 kg of phosphorus - containing phenolic resin (high - flame - retardant phosphorus - containing phenolic 950);

[0086] 15 kg of biphenyl - type epoxy resin (naphthalene - ring biphenyl epoxy resin NC3000H);

[0087] 12 kg of phenol - type phenolic epoxy resin (high - heat - resistant phenol special epoxy resin 638);

[0088] 8 kg of linear phenol - formaldehyde resin (linear phenol - formaldehyde PN 8020);

[0089] 5 kg of amine chain extender (3,3’ - diethyl 4,4’ - diamino diphenyl methane H256);

[0090] 20 kg of the first organic solvent (propylene glycol methyl ether PM);

[0091] 20 kg of the second organic solvent (methyl ethyl ketone, MEK).

[0092] The silicon carbide powder is α-type silicon carbide, P-type doped, with a particle size range of 5 - 10 μm.

[0093] The preparation method includes the following steps:

[0094] (1) Put the preset weight of o-cresol novolac epoxy resin, amine chain extender, and the first organic solvent into a stirring reaction kettle and mix them together. Stir and react at 100 °C, with a rotation speed of 500 r / min and a reaction duration of 4 h to form a slurry.

[0095] (2) After the slurry is cooled to room temperature, take a small amount for reactivity testing. If the viscosity-average molecular weight Mw is 200 - 300 and the Tg is 180 °C, it is qualified and proceed to the next step.

[0096] (3) Add the preset weight of linear phenol formaldehyde resin and the second organic solvent to the slurry obtained in step (1) and stir and react at a rotation speed of 150 r / min. After fully dissolving and mixing, maintain the reaction for 2.0 h.

[0097] (4) Continue to add the preset weight of biphenyl-type epoxy resin and stir and react at a rotation speed of 150 r / min. After fully dissolving and mixing, maintain the reaction for 2.5 h.

[0098] (5) Continue to add the preset weight of phenol-type novolac epoxy resin and phosphorus-containing phenol formaldehyde resin and stir and react at a rotation speed of 300 r / min, maintaining the reaction for 1.2 h.

[0099] (6) Continue to add the preset weight of silicon carbide powder and stir and mix and react at a speed of 450 r / min for 4.5 hours. If the viscosity is 300 - 500 s, it is qualified, and a thermal conductive coating is prepared.

[0100] (7) Prepare fiberglass cloth, completely immerse the (flat E-glass cloth) in the thermal conductive coating for 5 min. The weight of the fiberglass cloth is 30 wt% of the thermal conductive coating, then press and finally dry and cool to cure to make a high thermal conductive substrate with a fiberglass cloth layer and a thermal conductive layer.

[0101] The parameters of the electronic grade fiberglass cloth are shown in the following table.

[0102]

[0103] (8) Prepare a conductive copper foil with a thickness of 30 μm, cover the outer plate surface of the high thermal conductive substrate with the conductive copper foil, and press at a pressing temperature of 250 °C for 4 h.

[0104] Comparative Example 1

[0105] This comparative example contains the following raw materials for preparation by weight:

[0106] 75 kg of silicon carbide powder;

[0107] 15 kg of o-cresol novolac epoxy resin (o-cresol novolac special epoxy resin 704);

[0108] 15 kg of phosphorus-containing phenolic resin (high flame-retardant phosphorus-containing phenolic 950);

[0109] 15 kg of biphenyl-type epoxy resin (naphthalene ring biphenyl epoxy resin NC3000H);

[0110] 12 kg of phenol-type phenolic epoxy resin (high heat-resistant phenol special epoxy resin 638);

[0111] 8 kg of linear phenol formaldehyde resin (linear phenol formaldehyde PN 8020);

[0112] 5 kg of amine chain extender (3,3'-diethyl 4,4'-diaminodiphenylmethane H256);

[0113] 20 kg of the first organic solvent (propylene glycol methyl ether PM);

[0114] 20 kg of the second organic solvent (methyl ethyl ketone MEK).

[0115] The silicon carbide powder is α-type silicon carbide, P-type doped, and the particle size range is 10 - 15 μm.

[0116] The preparation method includes the following steps:

[0117] (1) Put the preset weight of o-cresol novolac epoxy resin, amine chain extender and the first organic solvent into a stirring reaction kettle and mix them together. Stir and react at 100 °C, the rotation speed is 500 r / min, and the reaction duration is 4 h to make a slurry.

[0118] (2) After the slurry is cooled to room temperature, take a small amount for reactivity testing. If the viscosity-average molecular weight Mw is 200 - 300 and the Tg is 180 °C, it is qualified and proceed to the next step.

[0119] (3) Add the preset weight of linear phenol formaldehyde resin and the second organic solvent to the slurry prepared in step (1) and stir and react. The rotation speed is 150 r / min. After fully dissolving and mixing, keep reacting for 2.0 h.

[0120] (4) Continue to add the preset weight of biphenyl-type epoxy resin and stir and react. The rotation speed is 150 r / min. After fully dissolving and mixing, keep reacting for 2.5 h.

[0121] (5) Continuously add a preset weight of phenol-type phenolic epoxy resin and phosphorus-containing phenolic resin and carry out a stirring reaction at a rotation speed of 300 r / min for 1.2 h.

[0122] (6) Continuously add a preset weight of silicon carbide powder and carry out a stirring and mixing reaction at a speed of 450 r / min for 4.5 hours. If the viscosity is 300 - 500 s, it is qualified, and a coating is prepared.

[0123] (7) Prepare a glass fiber cloth, completely immerse the (flat E-glass fiber cloth) in the coating for 5 min. The weight of the glass fiber cloth is 30 wt% of the coating, then press it, and finally dry and cool it for curing to make a substrate.

[0124] The parameters of the electronic-grade glass fiber cloth are shown in the following table.

[0125]

[0126] (8) Prepare a conductive copper foil with a thickness of 30 μm, cover the outer plate surface of the substrate with the conductive copper foil, and press it at a pressing temperature of 250 °C for 4 h.

[0127] Comparative Example 2

[0128] This comparative example contains the following weights of preparation raw materials:

[0129] 50 kg of silicon carbide powder;

[0130] 10 kg of o-cresol novolac epoxy resin (o-cresol novolac special epoxy resin 704);

[0131] 10 kg of phosphorus-containing phenolic resin (high flame-retardant phosphorus-containing phenolic 950);

[0132] 10 kg of biphenyl-type epoxy resin (naphthalene ring biphenyl epoxy resin NC3000H);

[0133] 8 kg of phenol-type phenolic epoxy resin (high heat-resistant phenol special epoxy resin 638);

[0134] 5 kg of linear phenol formaldehyde resin (linear phenol formaldehyde PN 8020);

[0135] 3 kg of chain extender (MOEA);

[0136] 15 kg of the first organic solvent (propylene glycol methyl ether PM);

[0137] 15 kg of the second organic solvent (methyl ethyl ketone MEK).

[0138] The silicon carbide powder is α-type silicon carbide, P-type doped, and the particle size range is 5 - 10 μm.

[0139] The preparation method includes the following steps:

[0140] (1) Put the preset weight of o-cresol novolac epoxy resin, chain extender and the first organic solvent into a stirring reactor and mix them together. Stir and react at 80 °C with a rotation speed of 400 r / min for 2.5 h to prepare a slurry.

[0141] (2) After the slurry is cooled to room temperature, take a small amount for reactivity testing. If the viscosity-average molecular weight Mw is 200 - 300 and the Tg is 180 °C, it is qualified and proceed to the next step.

[0142] (3) Add the preset weight of linear phenol formaldehyde resin and the second organic solvent to the slurry prepared in step (1) and stir and react at a rotation speed of 125 r / min. After fully dissolving and mixing, maintain the reaction for 1.5 h.

[0143] (4) Continue to add the preset weight of biphenyl-type epoxy resin and stir and react at a rotation speed of 125 r / min. After fully dissolving and mixing, maintain the reaction for 2.0 h.

[0144] (5) Continue to add the preset weight of phenol-type phenol formaldehyde epoxy resin and phosphorus-containing phenol formaldehyde resin and stir and react at a rotation speed of 250 r / min for 1.0 h.

[0145] (6) Continue to add the preset weight of silicon carbide powder and stir and mix and react at a speed of 400 r / min for 4.0 hours. If the viscosity is 300 - 500 s, it is qualified to prepare the coating.

[0146] (7) Prepare a fiberglass cloth, completely immerse the (E-glass cloth) in the coating for 4 min. The weight of the fiberglass cloth is 30 wt% of the coating, then press and finally dry and cool to cure to make a substrate.

[0147] The parameters of the electronic-grade fiberglass cloth are shown in the following table.

[0148]

[0149] (8) Prepare a conductive copper foil with a thickness of 30 μm, cover the conductive copper foil on the outer plate surface of the substrate, and press at a pressing temperature of 200 °C for 3 h.

[0150] Comparative Example 3

[0151] This comparative example contains the following weights of preparation raw materials:

[0152] 50 kg of silicon carbide powder;

[0153] 10 kg of o-cresol novolac epoxy resin (o-cresol novolac special epoxy resin 704);

[0154] 10 kg of phosphorus-containing phenol formaldehyde resin (high flame-retardant phosphorus-containing phenol formaldehyde 950);

[0155] 10 kg biphenyl-type epoxy resin (naphthalene ring biphenyl epoxy resin NC3000H);

[0156] 8 kg phenol-type phenolic epoxy resin (high heat-resistant special phenol epoxy resin 638);

[0157] 5 kg linear phenol formaldehyde resin (linear phenol formaldehyde PN 8020);

[0158] 3 kg amine chain extender (3,3'-diethyl-4,4'-diaminodiphenylmethane H256);

[0159] 15 kg first organic solvent (propylene glycol monomethyl ether PM);

[0160] 15 kg second organic solvent (methyl ethyl ketone MEK).

[0161] The silicon carbide powder is α-type silicon carbide, P-type doped, with a particle size range of 5 - 10 μm.

[0162] The preparation method includes the following steps:

[0163] (1) Put the above-mentioned preset weights of preparation raw materials into a stirring reaction kettle and mix them together. Stir and react at 80 °C, with a rotation speed of 400 r / min and a reaction duration of 8 h to obtain the coating.

[0164] (2) Prepare fiberglass cloth, completely immerse (E-glass cloth) in the coating for 4 min. The weight of the fiberglass cloth is 30 wt% of the coating, then press it, and finally dry and cool it for curing to make the substrate.

[0165] The parameters of the electronic-grade fiberglass cloth are shown in the following table.

[0166]

[0167] (8) Prepare a conductive copper foil with a thickness of 30 μm, cover the conductive copper foil on the outer surface of the substrate, and press it at a pressing temperature of 200 °C for 3 h.

[0168] Performance test

[0169] Test samples with a thickness of 0.12 - 0.13 mm are made from Examples 1 to 3 and Comparative Examples 1 to 3 for the following tests.

[0170] (1) Use ASTM-5470 to measure the thermal conductivity at 25 °C and 80 °C.

[0171] (2) Insulation performance test: The breakdown voltage is determined according to GB / T 1408.1-2016 "Test Method for Electrical Strength of Insulating Materials". Test conditions: Alternating current; Voltage boosting method: Short-time (rapid) test; Voltage boosting rate: 500 V / s.

[0172] (3) Leakage detection conditions: Withstand voltage value: 4000 VDC; Test time: 1 min; Voltage boosting rate: 500 V / s, Judgment current: ≤5 mA.

[0173] (4) Determine the glass transition temperature (Tg, DSC) and the thermal decomposition temperature; Measure the duration of delamination when continuously heated at 288°C.

[0174] (5) Determine the dielectric constant: The dielectric constant is determined by the resonant cavity test method. The resonant cavity test method uses a network analyzer to measure the resonant frequency and the Q value of the resonant cavity fixture. It is set to blank at the start of the test and then the sample to be measured is loaded. When the volume of the sample and other parameters of the resonant cavity are known, the dielectric constant is calculated through these measurements.

[0175]

[0176] According to the disclosure and teachings of the above specification, those skilled in the art to which the present invention pertains can also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A high thermal conductivity substrate, characterized in that: The preparation comprises the following raw materials in parts by weight: 30-70 parts of silicon carbide powder, 5-15 parts of o-cresol epoxy resin, 5-15 parts of phosphorus-containing phenolic resin, 3-15 parts of biphenyl epoxy resin, 2-13 parts of phenolic phenolic epoxy resin, 3-8 parts of linear phenol formaldehyde resin, 1-5 parts of amine chain extender, 5-20 parts of a first organic solvent and 5-20 parts of a second organic solvent.

2. The high thermal conductivity substrate according to claim 1, characterized in that: The silicon carbide powder is α-type silicon carbide.

3. The high thermal conductivity substrate according to claim 2, characterized in that: The silicon carbide powder is P-type doped.

4. The high thermal conductivity substrate according to claim 1, characterized in that The particle size of the silicon carbide powder is in the range of 5 to 10 μm.

5. The high thermal conductivity substrate according to claim 1, characterized in that: The o-cresol epoxy resin is o-cresol special epoxy resin 704; The first organic solvent is propylene glycol methyl ether; The amine chain extender is 3,3'-diethyl 4,4'-diaminodiphenylmethane H256.

6. The high thermal conductivity substrate according to claim 5, characterized in that: The phenol-type novolac epoxy resin is a high heat-resistant phenol special epoxy resin 638; The linear phenol formaldehyde resin is linear phenol formaldehyde PN 8020; The phosphorus-containing phenolic resin is highly flame-retardant phosphorus-containing phenolic 950; The biphenyl type epoxy resin is naphthalene biphenyl epoxy resin NC3000H; The second organic solvent is butanone.

7. The high thermal conductivity substrate according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) mixing a preset weight amount of o-cresol epoxy resin, an amine chain extender and a first organic solvent, stirring and reacting at 60 to 100° C., a rotation speed of 300 to 500 r / min, and a reaction time of 1 to 4 hours to prepare a slurry; (2) After the slurry is cooled to room temperature, a small amount is taken for reactivity test. If the viscosity average molecular weight Mw is 200-300 and the Tg is 180°C, it is qualified and proceed to the next step; (3) adding a predetermined weight portion of linear phenol formaldehyde resin and a second organic solvent to the slurry prepared in step (1) and stirring the mixture at a speed of 100 to 150 r / min. After the mixture is fully dissolved and mixed, the mixture is allowed to react for 1 to 2 hours. (4) Continue to add a preset weight portion of biphenyl epoxy resin for stirring reaction at a speed of 100 to 150 r / min. After sufficient dissolution and mixing, keep the reaction for 1.5 to 2.5 hours; (5) continuing to add a preset weight portion of phenol-type novolac epoxy resin and phosphorus-containing phenolic resin for stirring reaction at a speed of 200 to 300 r / min, and maintaining the reaction for 0.8 to 1.2 h; (6) Continue to add a preset weight portion of silicon carbide powder, stir and mix at a speed of 300 to 450 r / min for 3.5 to 4.5 hours, and the viscosity is 300 to 500 s, which is qualified, to obtain a thermal conductive coating; (7) Prepare glass fiber cloth, immerse the glass fiber cloth completely in the thermal conductive coating, the weight of the glass fiber cloth is 15-45wt% of the thermal conductive coating, press it, and finally dry and cool it to solidify, so as to prepare a high thermal conductive substrate with a glass fiber cloth layer and a thermal conductive layer.

8. The high thermal conductivity substrate according to claim 7, characterized in that: In step (7), the glass fiber cloth is completely immersed in the thermal conductive coating for at least 3 minutes.

9. The high thermal conductivity substrate according to claim 7 or 8, characterized in that: In step (7), the glass fiber cloth is electronic grade glass fiber cloth; The electronic grade glass fiber cloth is one of NE-glass fiber cloth, E-glass fiber cloth and flat E-glass fiber cloth.

10. The high thermal conductivity substrate according to claim 7 or 8, characterized in that: A conductive copper foil is laminated on one or both sides of the high thermal conductivity substrate, and the conductive copper foil has a thickness of 9 to 75 μm; The pressing operation is: covering the conductive copper foil on the outer surface of the high thermal conductivity substrate, and pressing at a pressing temperature of 150 to 280° C. for 2 to 4 hours.

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