CN115083660A - A kind of easy grinding high thermal conductivity insulating plug hole slurry, preparation method and application thereof - Google Patents

Abstract

The invention discloses an easy-to-grind high thermal conductivity insulating plug hole slurry, a preparation method and an application thereof. The insulating plug hole slurry comprises the following components by weight: 80-93wt% insulating and thermally conductive powder, 6- 15wt% resin, 0.2-2wt% curing agent, 0.8-3wt% auxiliary agent. The insulating plug hole paste of the present invention can match high Tg and low CTE plates, and has the characteristics of high thermal conductivity, anti-sag flow and easy grinding after curing, and is especially suitable for ceramic substrates, 5G high frequency and high power plates Use on the plug hole.

Description

A kind of easy grinding high thermal conductivity insulating plug hole slurry, preparation method and application thereof

technical field

The technical field of the plug hole slurry of the present invention, in particular, relates to an easy-to-grind high thermal conductivity insulating plug hole slurry, a preparation method and an application thereof.

Background technique

With the rapid development of microelectronics technology, the integration density and assembly density of electronic products continue to increase. As the carrier of electronic components, PCBs have higher integration density and higher power consumption requirements of components, especially in the context of 5G. The heat conduction and heat dissipation requirements of high-frequency and high-power boards are becoming more and more urgent, which put forward higher requirements for various properties of PCB materials. The traditional plug hole paste has a small thermal conductivity, a large thermal expansion coefficient, and a low glass transition temperature, which is difficult to meet the thermal conductivity and heat dissipation requirements of high-frequency and high-power boards under 5g conditions.

Plug hole paste is a material that fills PCB vias and buried holes through resin plugging process. It is very popular in PCB products with high layers and large thickness. The thermal conductive paste for plug holes on the market is mainly conductive paste, which has both thermal conductivity. Although its thermal conductivity is high, the cost of conductive paste is high, and the storage stability is poor, making it difficult to use in large quantities on PCB boards. In addition, the filler used in the conductive paste is generally metal powder, which has a large thermal expansion coefficient and cannot match high-frequency and high-power plates.

The insulating and thermally conductive plug hole slurry filled with ceramic powder has a small thermal expansion coefficient and low cost, and can be used in large quantities on 5G plates. For example, the applicant's early patent CN109929220B discloses an insulating and heat-conducting paste and its preparation method and application. The insulating and heat-conducting glue includes the following components: insulating and heat-conducting powder, resin, monomer, curing agent and auxiliary agent; The patented insulating and thermally conductive paste makes the components uniformly dispersed through the synergistic action of the contained combinations, the paste system is stable, the storage time is long, and it has the characteristics of high insulation, high thermal conductivity and ultra-low expansion coefficient. This patent uses a small particle size powder roller mill, but the interface thermal resistance of this small particle size powder is large, and it is difficult to improve the thermal conductivity, that is, the thermal conductivity of the insulating and thermally conductive paste in the prior art after curing is still difficult to achieve It can meet the heat conduction and heat dissipation requirements of high-frequency and high-power boards, and the sagging phenomenon is prone to occur during the baking process, resulting in a decline in the subsequent easy grinding performance, and it is difficult to meet the production requirements. The easy grinding performance is the technical pain point of using ceramic powder as the slurry filled with powder, because ceramic brushes are required for grinding. Ceramic brushes are expensive and consumables. The easy grinding characteristics can significantly reduce grinding costs and improve grinding. efficiency.

Therefore, there is still a need to develop an insulating paste with higher thermal conductivity, lower high temperature thermal expansion coefficient, and easy grinding.

SUMMARY OF THE INVENTION

In order to solve the problems existing in the prior art, the present invention provides an easy-to-grind high thermal conductivity insulating plug hole slurry, which is especially suitable for plug holes on ceramic substrates, 5G high frequency and high power plates.

Another object of the present invention is to provide a method for preparing the above-mentioned easy-to-grind high-thermal-conductivity insulating plug-hole slurry.

Another object of the present invention is to provide the application of this easy-to-grind high thermal conductivity insulating plug hole paste.

For realizing the above object of the invention, the present invention adopts the following technical scheme:

An easy-to-grind high thermal conductivity insulating plug hole slurry, comprising the following components by weight:

80-93wt% insulating and thermally conductive powder;

6-15wt% resin;

0.2-2wt% curing agent;

0.8-3wt% additives.

In a specific embodiment, the insulating and thermally conductive powder is selected from at least any two of boron nitride, aluminum oxide, and aluminum nitride, preferably aluminum oxide and aluminum nitride, or aluminum oxide and boron nitride.

In a specific embodiment, the shape of the insulating and thermally conductive powder is a combination of at least any two of flake, spheroid, spherical or angular; preferably, the insulating and thermally conductive powder is spherical, spheroid or Angular alumina powder and flake boron nitride powder; more preferably, the alumina powder is an alumina powder modified for the resin system, and the alumina powder and boron nitride are The mass ratio of the powder is 80:1 to 10:1.

In a specific embodiment, the insulating and thermally conductive powder includes small particles of insulating and thermally conductive powder with an average particle size of 0.5-1 μm and large particles of insulating and thermally conductive powder with an average particle size of 10-15 μm, and the insulating and thermally conductive powder The maximum particle size is not more than 40 μm; preferably, the mass ratio of the small particle insulating and thermally conductive powder to the large particle insulating and thermally conductive powder is 5:1-50:1.

In a specific embodiment, the resin is a liquid epoxy resin without organic solvent, preferably selected from bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic epoxy resin, silicone modified epoxy resin At least any one of the epoxy resins with special multifunctional groups; more preferably one of liquid bisphenol A epoxy resins, bisphenol F epoxy resins or special multifunctional epoxy resins species or a combination of several.

In a specific embodiment, the curing agent is selected from at least any one of amino resins, imidazoles, organic acid anhydrides and dicyandiamides; preferably imidazoles and dicyandiamides.

In a specific embodiment, the auxiliary agent includes a wetting and dispersing agent and a diluent; preferably, the wetting and dispersing agent is selected from one or two of modified polysiloxanes or polyurethane compounds combination; the diluent is an epoxy reactive diluent, preferably one or a combination of monofunctional glycidyl ethers or multifunctional glycidyl ethers.

On the other hand, a preparation method of the aforementioned easy-to-grind high thermal conductivity insulating plug hole slurry, comprising the following steps:

1) Mix a certain proportion of resin, curing agent, and insulating and thermally conductive powder with a particle size of not more than 15 μm through a high-speed mixer to obtain a preliminary base material;

2) using a three-roller machine to roll mill the initially dispersed base material in step 1) to obtain a thermally conductive base material;

3) Add auxiliaries and insulating and heat-conducting powder with a particle size larger than 15 μm to the heat-conducting base material in turn, and stir them evenly in the planetary stirring equipment to form the final easy-grinding high-heat-conductivity insulating plug hole slurry.

In a specific embodiment, in the step 2), the rotational speed of the roller mill is 200r/min-300r/min, and the roller mill can be milled to a fineness of less than 15 microns; preferably, in the step 3), the stirring The rotation speed is 1500r/min-2000r/min, and the duration is 2-5 hours.

In yet another aspect, an application of the aforementioned easy-to-grind high-thermal-conductivity insulating plug-hole slurry or the easy-to-grind high-thermal-conductivity insulating plug hole slurry prepared by the aforementioned method for plugging holes on ceramic substrates, 5G high-frequency or high-power plates.

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

High-frequency, high-power printed circuit boards are used in the 5g field, and plugging pastes with higher thermal conductivity and lower thermal expansion coefficient are required to match them, and in order to improve the grinding efficiency after plugging and reduce the cost of consumables for the grinding process , It is required that the slurry has the characteristics of easy grinding after curing. At present, the thermal conductive plug hole slurry needs to be ground through a three-roller, so powder with a particle size larger than 15 microns cannot be used in the selection of thermal conductive powder. The thermal conductivity powder with small particle size has a large oil absorption, which easily leads to a rapid increase in the viscosity of the system, and because the powder with small particle size is more fully encapsulated by the resin, the interface thermal resistance is large, and it is difficult to improve the thermal conductivity.

The easy-to-grind high-thermal-conductivity insulating plug hole slurry provided by the present invention can achieve high thermal conductivity through the combination of different shapes and different particle sizes of insulating powders, and can improve the storage stability of the system and the easy grinding of the solidified slurry. performance. First, the resin, the auxiliary agent, the curing agent and the powder with small particle size are dispersed uniformly to obtain the base material, and then the large particle size powder is added in a planetary mixer to uniformly stir in a vacuum to obtain a thermally conductive slurry. The preparation method provided by the present invention can ensure that both The powder with small particle size is uniformly dispersed, and can make the whole slurry system more stable. Small particle size powder and resin, additives and curing agent are uniformly milled by three-roller machine, which can avoid the agglomeration of small particle size powder, and better compatibility with resin can improve the thixotropic performance of the system; Due to the small specific surface area of the powder, the filling amount of the powder can be significantly increased, and the large particle size powder has a lower interfacial thermal resistance. The two synergize to improve the thermal conductivity and achieve high thermal conductivity.

The invention can further improve the storage stability of the system and improve the easy grinding performance of the cured slurry through the gradation of insulating powders of different shapes and particle sizes and the selection of suitable resins and additives.

After the insulating plug hole paste of the present invention is cured by suitable curing conditions, the thermal expansion coefficient is ultra-low, which can match the ceramic substrate, and the glass transition temperature is high. In addition, due to the use of graded powder of specific shape and particle size, the amount of filler can be significantly increased, the sag phenomenon of the slurry during the baking process can be improved, and the conditions of highly selective plugging can be satisfied.

Description of drawings

Fig. 1 is a schematic flow chart of the preparation method of the present invention.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific implementations described herein are only used to explain the present invention, but not to limit the present invention.

As shown in Figure 1, the easy-to-grind high thermal conductivity insulating plug hole slurry of the present invention is prepared by the following steps:

1) Weigh the resin, curing agent, and insulating and thermally conductive powder with a particle size of less than or equal to 15 microns in proportion, and mix them evenly with a high-speed mixer to obtain a preliminary dispersed base material;

2) Roll mill the preliminarily dispersed base material with a three-roller machine, and control the fineness to be less than 15 microns, further improve the dispersion performance of the powder in the resin, and obtain a thermally conductive base material;

3) Add auxiliaries and insulating and heat-conducting powder with a particle size larger than 15 microns in turn to the heat-conducting base material, and vacuum stirring for 0.5h in a planetary stirring device to form the final heat-conducting slurry.

Wherein, the weight percentages of resin, curing agent, insulating and thermally conductive powder and auxiliary agent are 80-93wt% insulating and thermally conductive powder, 6-15wt% resin, 0.2-2wt% curing agent, and 0.8-3wt% auxiliary agent.

Wherein, the weight percentage of insulating and thermally conductive powder includes but is not limited to 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93% %; The weight percentage of resin includes but not limited to 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%; The weight percentage of curing agent includes but not limited to 0.3 %, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%; the weight percentages of additives include but are not limited to 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%.

The insulating and thermally conductive powders include insulating and thermally conductive powders with an average particle size of 0.5-1 μm and insulating and thermally conductive powders with an average particle size of 10-15 μm, and the maximum particle size of the insulating powders is less than or equal to 40 μm. In the preparation process, the insulating and heat-conducting powder is sieved according to the particle size, and the insulating and heat-conducting powder with different particle sizes is added in different steps. The small particle size powder can prevent the slurry from sagging during the baking process to improve the easy grinding performance, and the large particle size powder can significantly increase the amount of filler added to improve the thermal conductivity.

The insulating and heat-conducting powder is at least two kinds of boron nitride, aluminum oxide, and aluminum nitride; the shape of the insulating and heat-conducting powder is at least two combinations of flake, spheroid, spherical and angular; one In a preferred solution, the insulating and thermally conductive powder is a mixed powder of alumina and aluminum nitride or a mixed powder of alumina and boron nitride. Due to their low density, aluminum nitride and boron nitride can prevent slurry The vertical flow can meet the conditions of highly selective plugging, so that the solidified slurry has the characteristics of easy grinding. In a more preferred solution, the alumina and boron nitride mixed powder, wherein the shape of the alumina powder is spherical, spheroid or angular, and the alumina powder is a powder modified for the resin system , The modified alumina powder can improve the compatibility with the resin, significantly reduce the viscosity of the system, and increase the amount of filler added, thereby improving the thermal conductivity of the product. The boron nitride powder is in the form of flakes, and the mass ratio of the alumina powder to the boron nitride powder is 80:1 to 10:1. The spherical/sub-spherical and angular powders are filled into the voids of the flake powders to form tighter packing and improve thermal conductivity.

Specifically, the modified alumina powder is mainly aimed at the modification of the epoxy system. The silicon-oxygen bond in the silane coupling agent is used to form a chemical bond with the hydroxyl group on the surface of the alumina powder. The organic molecules are tightly wrapped on the surface of the powder, which makes the surface of the powder organic and increases the compatibility with the organic system. For example, the specific modification method is chemical coupling modification, using dipropylene glycol methyl ether as solvent, alumina powder: silane coupling agent amount=1000:1.4, stirring for 2-5h, and baking at 130°C for 1.5- 3h, the modified powder is obtained. Wherein, the silane coupling agent can be vinyl tris-(βmethoxyethoxysilane), γ-mercaptopropyl trimethoxysilane, γ-glycidyl ether propyl trimethoxysilane, β-(3, At least any one of 4 epoxyhexyl) ethyl trimethoxy silane.

The resin is a liquid epoxy resin without organic solvent, including bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, silicone modified epoxy resin and special multifunctional cyclic epoxy resin. One or several combinations of oxygen resins, etc., but not limited thereto. Liquid epoxy resin, as the polymer matrix resin of insulating and thermally conductive paste, has excellent physical properties, electrical insulating properties and bonding properties. In a preferred solution, the liquid epoxy resin is one or several combinations of liquid bisphenol A epoxy resin, bisphenol F epoxy resin and special multifunctional epoxy resin. Low viscosity, excellent chemical resistance, high temperature resistance, high crosslinking density and other characteristics.

The curing agent is at least one of amino resins, imidazoles, organic acid anhydrides and dicyandiamides. The curing agent and the host resin have a long storage period and have good physical and mechanical properties after curing at a suitable baking temperature.

The auxiliary agent includes a wetting and dispersing agent, a diluent, etc.; the wetting and dispersing agent is one or a combination of modified polysiloxane or a polyurethane compound; the diluent is an epoxy reactive diluent. The agent is one or several combinations of monofunctional glycidyl ether or multifunctional glycidyl ether; the wetting and dispersing agent can disperse each component evenly, and the epoxy diluent contains active epoxy functional groups and participates in the reaction. And it is used to adjust the viscosity and at the same time improve the storage stability of the thermally conductive paste. According to the type of the auxiliary agent, the auxiliary agent can improve the excellent stability of the dispersion system of the insulating and thermally conductive paste, and improve the stability.

The present invention is further explained and illustrated by more specific examples below, but does not constitute any limitation.

The modified alumina powders used in the examples were all prepared by the following methods:

Dipropylene glycol methyl ether was used as the solvent, the amount of alumina powder: silane coupling agent (γ-mercaptopropyl trimethoxysilane) = 1000: 1.4, stirring for 3 hours, and baking at 130 °C for 2 hours, the modification was obtained. powder.

Example 1

This embodiment provides an insulating and thermally conductive paste, and the insulating and thermally conductive paste includes the following mass percentages: 3% of liquid bisphenol A epoxy resin, 5% of liquid bisphenol F epoxy resin, and a curing agent ( Ajinomoto PN-40, imidazoles) 0.6%, modified spherical alumina 79.5% (D50=14μm), modified flake alumina (D50≤7μm) 10%, flake boron nitride (average particle size) ≤1 μm) 2%, p-tert-butylphenyl glycidyl ether 1.9%.

Its preparation method comprises the following steps:

1. Weigh bisphenol A epoxy resin, bisphenol F epoxy resin, imidazole curing agent, modified spherical alumina with particle size not exceeding 15 μm, modified flaky alumina, After the boron nitride is mixed evenly, it is rolled on a three-roller machine, and the fineness is less than 15 microns for three times by controlling the gap between the rolls to obtain the base material;

2. While stirring, add p-tert-butylphenyl glycidyl ether and large-diameter thermally conductive powder with a particle size of more than 15 μm into the base material for high-speed stirring, and transfer the stirred slurry to a vacuum mixer for vacuum stirring 2h;

3. Set the defoaming procedure of the vacuum-stirred slurry in the revolution and self-rotating defoaming machine to carry out vacuum defoaming to obtain thermally conductive slurry.

Comparative Example 1

This comparative example provides an insulating and thermally conductive paste. The insulating and thermally conductive paste includes the following mass percentages: 3% of liquid bisphenol A epoxy resin, 5% of liquid bisphenol F epoxy resin, and a curing agent (Japan Ajinomoto PN-40, imidazoles) 0.6%, modified spherical alumina (maximum particle size≤15μm) 79.5%, modified flake alumina (D50≤7μm) 10%, flake boron nitride (average particle size) diameter≤1μm) 2%, p-tert-butylphenyl glycidyl ether 1.9%.

Its preparation method comprises the following steps:

1. Weigh bisphenol A type epoxy resin, bisphenol F type epoxy resin, curing agent, all modified spherical alumina, modified flaky alumina, flaky boron nitride, p-tert-butylene according to the above formula base phenyl glycidyl ether, carry out preliminary mixing, and then carry out roll grinding on a three-roll machine, and control the gap between the rolls for three times of roll grinding with a fineness of less than 15 microns, that is, a preliminary slurry is obtained;

2. Transfer the slurry to a planetary mixer for vacuum stirring for 2h;

3. Set the defoaming program in the revolution and auto-rotating defoaming machine to perform vacuum defoaming of the stirred slurry to obtain thermally conductive slurry.

Comparative Example 2

This embodiment provides an insulating and heat-conducting paste, and the insulating and heat-conducting paste comprises the following mass percentages: 10% liquid phenolic epoxy resin (Dow), curing agent (Ajinomoto PN-40, imidazole) ) 0.8%, modified spherical alumina (D100=15 μm) 84%, flake boron nitride (D50=3 μm) 4.2%, butanediol diglycidyl ether 1%.

1. Weigh the liquid phenolic epoxy resin, imidazole curing agent, and flake boron nitride according to the content in the above formula, and then roll them on a three-roller machine. Less than 15 microns, the base material is obtained;

2. While stirring, sequentially add butanediol diglycidyl ether and modified spherical thermally conductive powder into the base material for high-speed stirring, and transfer the stirred slurry to a vacuum mixer for vacuum stirring for 2 hours;

3. Set the defoaming procedure of the vacuum-stirred slurry in the revolution and self-rotating defoaming machine to carry out vacuum defoaming to obtain thermally conductive slurry.

Example 2

This embodiment provides an insulating and heat-conducting paste, and the insulating and heat-conducting paste comprises the following mass percentages: 10% liquid phenolic epoxy resin (Dow), curing agent (Ajinomoto PN-40, imidazole) ) 0.8%, modified spherical alumina (D50=13 μm) 84%, flake boron nitride (D50=3 μm) 4.2%, butanediol diglycidyl ether 1%.

1. Weigh the liquid phenolic epoxy resin, imidazole curing agent, and flake boron nitride according to the content in the above formula, and then roll them on a three-roller machine. Less than 15 microns, the base material is obtained;

2. While stirring, sequentially add butanediol diglycidyl ether and modified spherical thermally conductive powder into the base material for high-speed stirring, and transfer the stirred slurry to a vacuum mixer for vacuum stirring for 2 hours;

3. Set the defoaming procedure of the vacuum-stirred slurry in the revolution and self-rotating defoaming machine to carry out vacuum defoaming to obtain thermally conductive slurry.

Example 3

This embodiment provides an insulating and thermally conductive paste, and the insulating and thermally conductive paste includes the following mass percentages: 6% of bisphenol A epoxy resin, 3% of special bifunctional epoxy resin, and a curing agent (Japanese flavored epoxy resin). PN-40, imidazoles) 0.6%, modified spherical alumina (D50=10 microns) 85.3%, flake boron nitride (D50=3 microns) 4.1%, ethylene glycol diglycidyl ether (South Asia) 1%.

Its preparation method comprises the following steps:

1. Weigh bisphenol A epoxy resin, special bifunctional epoxy resin, imidazole curing agent, and flake boron nitride according to the content in the above formula and mix them evenly, and then roll them on a three-roller machine. The gap between the two is rolled three times, and the fineness is less than 15 microns, that is, the base material is obtained;

2. While stirring, add p-tert-butylphenyl glycidyl ether and modified spherical alumina large-diameter thermally conductive powder into the base material for high-speed stirring, and transfer the stirred slurry to a vacuum mixer for vacuum stirring 2h;

3. Set the defoaming procedure of the vacuum-stirred slurry in the revolution and self-rotating defoaming machine to carry out vacuum defoaming to obtain thermally conductive slurry.

Example 4

This embodiment provides an insulating and thermally conductive paste. The insulating and thermally conductive paste includes the following mass percentages: 10% of silicone-modified epoxy resin, 0.1% of curing agent (Ajinomoto PN-40, imidazole) %, isocyanate 0.6%, modified angular alumina (D50=14 microns) 78.3%, flake boron nitride 8% (D50=3 microns), butanediol diglycidyl ether 3%.

1. Weigh the silicone-modified epoxy resin, imidazole curing agent, and flake boron nitride according to the content in the above formula, and then roll them on a three-roller machine, and roll them three times by controlling the gap between the rollers. When the fineness is less than 15 microns, the base material is obtained;

2. While stirring, add butanediol diglycidyl ether and modified angular alumina (D50=14 microns) large-diameter thermally conductive powder into the base material for high-speed stirring, and transfer the stirred slurry to a vacuum Vacuum stirring was carried out in the mixer for 2h;

3. Set the defoaming procedure of the vacuum-stirred slurry in the revolution and self-rotating defoaming machine to carry out vacuum defoaming to obtain thermally conductive slurry.

Example 5

This embodiment provides an insulating and thermally conductive paste. The insulating and thermally conductive paste includes the following mass percentages: 6% of bisphenol F epoxy resin, 4% of amine-based bifunctional epoxy resin, and a curing agent (Japanese flavor). Zinc PN-40, imidazoles) 0.6%, modified angular alumina (D50=14 microns) 63.4%, flake boron nitride (D50=3 microns) 25%, polypropylene glycol diglycidyl ether 1%.

1. Weigh bisphenol F-type epoxy resin, amine-based bifunctional epoxy resin, imidazole curing agent, and flake boron nitride (D50=3 microns) according to the content in the above formula and mix them evenly on a three-roller machine. Roller grinding, the base material is obtained by controlling the gap between the rollers for three times, and the fineness is less than 15 microns;

2. While stirring, add polypropylene glycol diglycidyl ether and modified angular alumina (D50=14 microns) large-diameter thermally conductive powder into the base material for high-speed stirring, and transfer the stirred slurry to a vacuum mixer Carry out vacuum stirring for 2h;

3. Set the defoaming procedure of the vacuum-stirred slurry in the revolution and self-rotating defoaming machine to carry out vacuum defoaming to obtain thermally conductive slurry.

Example 6

This embodiment provides an insulating and thermally conductive paste, and the insulating and thermally conductive paste includes the following mass percentages: aminophenol-based trifunctional epoxy resin 6%, curing agent (Ajinomoto PN-40, imidazole) 0.7%, modified spherical alumina (D50 = 14 microns) 68.3%, modified angular alumina (D50 = 14 microns) 17%, flake aluminum nitride (D50 = 3 microns) 5%, double head Epoxy resin 3%.

1. Weigh aminophenol-based trifunctional epoxy resin, imidazole type curing agent, and flake aluminum nitride according to the content in the above formula and mix them evenly, then roll them on a three-roller machine, and roll them three times by controlling the gap between the rollers. , the fineness is less than 15 microns to obtain the base material;

2. Add the double-head epoxy resin, spherical alumina and modified angular alumina into the base material in turn while stirring for high-speed stirring, and transfer the stirred slurry to a vacuum mixer for vacuum stirring for 2 hours;

3. Set the defoaming procedure of the vacuum-stirred slurry in the revolution and self-rotating defoaming machine to carry out vacuum defoaming to obtain thermally conductive slurry.

The insulating and thermally conductive pastes of Examples 1-6 and Comparative Examples 1-2 were subjected to plugging treatment. The plug hole processing method uses a vacuum screen printing process to plug the insulating and thermally conductive paste into the holes on the PCB board.

The PCB board after plugging is baked at the baking conditions of 110℃*0.5h+130℃*1h+150℃*0.5h, and the performance verification experiment is carried out after baking and curing. The thermal expansion rate is the data tested at 40-300°C, see Table 1 for details.

Table 1 Insulation plug hole slurry performance test data table

It can be seen from Table 1 that the technical solution provided by the present invention adopts the combination of large and small particle sizes and different types of powders, which can ensure a suitable printing process viscosity, reduce the interface thermal resistance, and thereby improve the thermal conductivity; and the present invention provides The technical solution can solve the sag phenomenon in the vertical baking process of the slurry, which greatly improves the easy grinding performance; at the same time, the adjustment of the formula components can improve the stability of the storage process and prolong the use time of the slurry.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. an easy-to-grind high thermal conductivity insulating plug hole slurry, is characterized in that, comprises the following components by weight: 80-93wt% insulating and thermally conductive powder; 6-15wt% resin; 0.2-2wt% curing agent; 0.8-3wt% additives. 2 . The easy-grindable high thermal conductivity insulating plug hole slurry according to claim 1 , wherein the insulating and thermally conductive powder is selected from at least any two of boron nitride, aluminum oxide, and aluminum nitride, and is preferably oxidized. 3 . Aluminum and aluminum nitride, or aluminum oxide and boron nitride. 3. The easy-to-grind high thermal conductivity insulating plug hole slurry according to claim 1 or 2, wherein the shape of the insulating and thermally conductive powder is at least any two of sheet-like, spherical-like, spherical or angular. combination; preferably, the insulating and thermally conductive powder is spherical, spheroidal or angular alumina powder and flake boron nitride powder; more preferably, the alumina powder is modified for resin system The alumina powder, the mass ratio of the alumina powder to the boron nitride powder is 80:1-10:1. 4. The easy-to-grind high thermal conductivity insulating plug hole slurry according to claim 3, wherein the insulating and thermally conductive powder comprises small-particle insulating and thermally conductive powder with an average particle size of 0.5-1 μm and an average particle size of 10 μm. -15μm large particle insulating and thermally conductive powder, and the maximum particle size of the insulating and thermally conductive powder does not exceed 40μm; preferably, the mass ratio of the small particle insulating and thermally conductive powder to the large particle insulating and thermally conductive powder is 5:1-50 :1. 5. The easy-to-grind high thermal conductivity insulating plug hole slurry according to claim 1, wherein the resin is a liquid epoxy resin that does not contain an organic solvent, preferably selected from bisphenol A epoxy resin, bisphenol A At least any one of phenol F epoxy resin, novolac epoxy resin, silicone modified epoxy resin, and special multifunctional epoxy resin; more preferably liquid bisphenol A epoxy resin, bisphenol One or several combinations of F-type epoxy resin or special multifunctional epoxy resin. 6. The easy-to-grind high thermal conductivity insulating plug hole slurry according to claim 1, wherein the curing agent is selected from at least any one of amino resins, imidazoles, organic acid anhydrides and dicyandiamides species; preferably imidazoles and dicyandiamides. 7. The easy-to-grind high thermal conductivity insulating plug hole slurry according to claim 1, wherein the auxiliary agent comprises a wetting and dispersing agent and a diluent; preferably, the wetting and dispersing agent is selected from modified One or two combinations of polysiloxanes or polyurethane compounds; the diluent is an epoxy reactive diluent, preferably one or more combinations of monofunctional glycidyl ethers or multifunctional glycidyl ethers . 8. The preparation method of the easy-to-grind high thermal conductivity insulating plug hole slurry according to any one of claims 1 to 7, characterized in that, comprising the following steps: 1) Mix a certain proportion of resin, curing agent, and insulating and thermally conductive powder with a particle size of not more than 15 μm through a high-speed mixer to obtain a preliminary base material; 2) using a three-roller machine to roll mill the initially dispersed base material in step 1) to obtain a thermally conductive base material; 3) Add auxiliaries and insulating and heat-conducting powder with a particle size larger than 15 μm to the heat-conducting base material in turn, and stir them evenly in the planetary stirring equipment to form the final easy-grinding high-heat-conductivity insulating plug hole slurry. 9. The preparation method according to claim 8, characterized in that, in the step 2), the rotational speed of the roller mill is 200r/min-300r/min, and the roller mill is fine to be less than 15 microns; preferably, The rotating speed of stirring in the step 3) is 1500r/min-2000r/min, and the duration is 2-5 hours. 10. The easy-to-grind high-thermal-conductivity insulating plug-hole slurry according to any one of claims 1 to 7 or the easy-to-grind high-thermal-conductivity insulating plug hole slurry prepared by the preparation method according to any one of claims 8 to 9 is applied to a ceramic substrate , 5G high-frequency or high-power plate plug hole application.

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