A magnetic paste for an inductor in a fully integrated voltage regulation module and its preparation method.

Abstract

This invention provides a magnetic paste for an inductor in a fully integrated voltage regulation module and its preparation method. The magnetic paste, by weight, comprises: 100 parts soft magnetic alloy powder, 9-13 parts binder, and 2.85-4.61 parts curing agent; wherein the binder includes bisphenol F type epoxy resin and an aromatic reactive diluent. The preparation method, through mechanical stirring and vacuum degassing, yields a magnetic paste with suitable viscosity and good high-temperature resistance. The preparation method of this invention is simple to operate, has low preparation cost, and is suitable for industrial application.

Description

Technical Field

[0001] This invention relates to the field of magnetic materials technology, and in particular to a magnetic paste for an inductor in a fully integrated voltage regulation module and its preparation method. Background Technology

[0002] The power supply systems for microprocessor modules in computers, servers, and data centers are currently shifting from traditional voltage regulator modules to fully integrated voltage regulator modules (FIVRs) that offer higher integration, stronger power supply capabilities, and lower costs. In FIVRs, the inductor is typically integrated into the packaging substrate. The specific process involves filling through-holes in the core layer of the packaging substrate with magnetic material, then creating smaller diameter through-holes within the magnetic material, and finally coupling one or more metal wires to these through-holes to achieve the inductor effect.

[0003] The inductors in FIVR have low inductance, typically tens of nH, very low DC resistance, high Q value, and high self-resonant frequency (up to 6 GHz). Considering the heat dissipation of the microprocessor, the power loss of these inductors must remain low at high frequencies. This requires the magnetic material filled into the via to have high-frequency, low-loss, and good stability performance.

[0004] CN105741997A discloses a magnetic paste, its preparation method, and a method for preparing magnetic sheets. The magnetic paste comprises magnetic powder and an organic carrier, with the mass ratio of magnetic powder to the organic carrier being 1:0.7 to 1:0.9. The organic carrier, by mass percentage, comprises 8% to 10% binder, 82% to 90% solvent, 0.1% to 1% defoamer, 0.1% to 1% dispersant, and 1% to 6% plasticizer. The binder is polyvinyl butyral, and the solvent includes alcohol solvents and ester solvents. The magnetic paste uses highly volatile alcohol and ester solvents, and the magnetic sheets prepared according to this magnetic paste formulation cannot operate in high-temperature environments.

[0005] CN112679820A discloses a polyethylene-based injection-molded magnetic composite material for inductors and its preparation method. The polyethylene-based injection-molded magnetic composite material for inductors consists of 5%-30% polyethylene substrate, 70%-95% magnetic filler, 1%-4% coupling agent, and 1%-4% additives. Furthermore, the polyethylene-based injection-molded magnetic composite material maintains its mechanical strength while being filled with highly magnetic filler. However, the preparation method is relatively complex, and the prepared soft magnetic composite material cannot operate in high-temperature environments.

[0006] CN111986866A discloses a high-frequency, low-magnetic-loss power-type soft magnetic composite material and its preparation method. A slurry casting process is used, mixing trimethylolpropane triacrylate, NiZn ferrite flake powder, permalloy spherical powder, dibutyl phthalate, and acetone, and vibrating the mixture in a ball mill to form a highly fluid magnetic slurry. The slurry is then injected into a mold, heated to cure, and cooled to demold, yielding the soft magnetic composite core. The core prepared from this high-frequency, low-magnetic-loss power-type soft magnetic composite material effectively reduces eddy current losses at high frequencies, and the entire preparation process does not require external pressure, simplifying the process. However, the trimethylolpropane triacrylate used as the polymer matrix in this high-frequency, low-magnetic-loss power-type soft magnetic composite material exhibits relatively poor high-temperature resistance after curing with the powder and other compounds, and acetone, a highly volatile solvent, is used.

[0007] CN112125656A discloses a low-temperature curing high-frequency, low-loss NiCuZn ferrite core material and a pressureless injection molding method. A premix is ​​prepared by mixing 2.5 wt.% of an aqueous solution of methacrylamide monomer, N,N'-methylenebisacrylamide, and 10 wt.% of an aqueous solution of polyethylene glycol 400 plasticizer. NiCuZn ferrite powder is added to the premix to obtain a gel slurry. An aqueous solution of ammonium persulfate and tetramethylethylenediamine are added to the slurry, which is then injected into a mold. After curing at room temperature and pressure, the material is demolded, the blank is dried, and finally sintered and cooled to obtain the magnetic core. The high-frequency, low-loss NiCuZn ferrite core material can be cured at room temperature without applying external pressure. However, the aqueous solution used accelerates the oxidation of the alloy powder at higher temperatures, leading to performance degradation. Furthermore, the preparation method of this magnetic slurry is relatively complex.

[0008] Therefore, it is of great significance to develop a magnetic paste for a fully integrated voltage regulation module inductor that is simple to prepare, has low magnetic loss and good high-temperature stability, and its preparation method. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a magnetic slurry for the inductor of a fully integrated voltage regulation module and its preparation method. The magnetic slurry comprises a specific ratio of soft magnetic alloy powder, binder, and curing agent. An aromatic reactive diluent is used to adjust the viscosity of the magnetic slurry, giving it suitable viscosity and good high-temperature resistance. The preparation method yields a high-performance magnetic slurry through mechanical stirring and vacuum degassing, is simple to operate, and has excellent prospects for industrial application.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a magnetic paste for an inductor of a fully integrated voltage regulation module, wherein, by mass parts, the raw materials of the magnetic paste include:

[0012] 100 parts of soft magnetic alloy powder, 9-13 parts of binder and 2.85-4.61 parts of curing agent;

[0013] The adhesive includes bisphenol F type epoxy resin and aromatic reactive diluent.

[0014] The aromatic reactive diluent in the magnetic paste of the fully integrated voltage regulation module inductor of this invention adjusts the viscosity of the magnetic paste, giving it good flow properties. This also avoids the performance degradation caused by the evaporation of volatile organic solvents as the temperature rises, which can lead to porosity in the inductor made from the magnetic paste, when using volatile organic solvents as raw materials. Within a specific ratio range, the magnetic paste of this invention has suitable viscosity and toughness, allowing it to fill the through-holes of the PCB. Drilling of the through-holes with the magnetic paste results in good performance without cracking, and the magnetic loss of the magnetic paste is low. The glass transition temperature of the cured magnetic paste of this invention is greater than 150°C, ensuring that the fully integrated voltage regulation module inductor can operate normally at higher temperatures.

[0015] The magnetic slurry of the present invention comprises 9 to 13 parts by weight of binder, for example, 9 parts, 9.3 parts, 9.5 parts, 10 parts, 11 parts, 12 parts, 12.5 parts or 13 parts, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0016] The magnetic slurry of the present invention comprises 2.85 to 4.61 parts of curing agent by weight, for example, 2.85 parts, 2.9 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts or 4.61 parts, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] Preferably, the raw materials of the magnetic slurry, by weight, include:

[0018] The mixture comprises 100 parts of soft magnetic alloy powder, 10-12 parts of binder, and 3.17-4.25 parts of curing agent; wherein the 10-12 parts of binder can be, for example, 10 parts, 10.3 parts, 10.5 parts, 11 parts, 11.2 parts, 11.5 parts, 11.7 parts, or 12 parts, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable; the 3.17-4.25 parts of curing agent can be, for example, 3.17 parts, 3.2 parts, 3.3 parts, 3.5 parts, 4 parts, 4.1 parts, or 4.25 parts, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0019] Preferably, the soft magnetic alloy powder comprises Fe-based amorphous alloy powder.

[0020] The soft magnetic alloy powder of the present invention preferably includes Fe-based amorphous alloy powder. Fe-based amorphous alloy powder has excellent DC superposition characteristics and low loss characteristics, which meets the requirement that the inductor of the fully integrated voltage regulation module prepared by the magnetic paste maintains low loss at high frequency.

[0021] Preferably, the particle size D50 of the soft magnetic alloy powder is 1 to 4 μm, for example, it can be 1 μm, 1.2 μm, 1.5 μm, 1.7 μm, 2 μm, 2.5 μm, 3 μm or 4 μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0022] Preferably, the mass ratio of bisphenol F epoxy resin to aromatic reactive diluent in the adhesive is 2:1 to 1:2, for example, it can be 2:1, 1.9:1.1, 1.7:1.5, 1.5:1.6, 1:1, 1.2:1.9 or 1:2, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] Preferably, the epoxy equivalent of the bisphenol F type epoxy resin is 150 to 190 g / eq, for example, it can be 150 g / eq, 155 g / eq, 160 g / eq, 170 g / eq, 180 g / eq or 190 g / eq, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] Preferably, the viscosity of the bisphenol F epoxy resin at 25°C is 2000–5000 cps, for example, 2000 cps, 2300 cps, 2500 cps, 3000 cps, 3500 cps, 4000 cps, 4500 cps, or 5000 cps, but it is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0025] Preferably, the epoxy equivalent of the aromatic reactive diluent is 100-140 g / eq, for example, it can be 100 g / eq, 105 g / eq, 110 g / eq, 120 g / eq, 130 g / eq, 135 g / eq or 140 g / eq, etc., but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0026] Preferably, the viscosity of the aromatic active diluent at 25°C is 50 to 500 cps, for example, it can be 50 cps, 70 cps, 90 cps, 100 cps, 200 cps, 300 cps, 400 cps or 500 cps, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Preferably, the aromatic reactive diluent is a compound whose molecular structure contains a benzene ring and has one or more epoxy groups.

[0028] Preferably, the curing agent comprises diethyltoluene diamine and / or isoflurane diamine.

[0029] Preferably, the viscosity of the magnetic slurry is 40,000 cp to 160,000 cp, for example, it can be 40,000 cp, 50,000 cp, 80,000 cp, 100,000 cp, 120,000 cp, 140,000 cp, 150,000 cp or 160,000 cp, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] In a second aspect, the present invention also provides a method for preparing magnetic paste for the inductor of a fully integrated voltage regulation module as described in the first aspect, characterized in that the preparation method includes the following steps:

[0031] (1) According to the mass fraction, 9-13 parts of adhesive and 2.85-4.61 parts of curing agent are mixed, and after the first stirring, 100 parts of soft magnetic alloy powder are added and stirred for the second time to obtain a semi-finished magnetic slurry.

[0032] (2) The semi-finished magnetic slurry is subjected to vacuum degassing treatment to obtain the magnetic slurry for the inductor of the fully integrated voltage regulation module.

[0033] The method for preparing the magnetic paste for the inductor of the fully integrated voltage regulation module described in this invention involves first mixing liquid raw material binder and curing agent by mechanical stirring, and then adding solid soft magnetic alloy powder for further mixing. This ensures uniform mixing of all raw materials. The semi-finished magnetic paste is then subjected to vacuum degassing to remove air bubbles, preventing voids in the inductor and ensuring its performance. This preparation method is simple to operate, has low production costs, and is suitable for industrial application.

[0034] Preferably, the stirring speed of the first stirring step (1) is 50 to 150 rpm, for example, it can be 50 rpm, 80 rpm, 100 rpm, 110 rpm, 120 rpm, 140 rpm or 150 rpm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the first stirring time is 10 to 30 minutes, for example, it can be 10 minutes, 12 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, both the first and second stirring are carried out in a mechanical mixer.

[0037] Preferably, the second stirring speed is 50 to 200 rpm, for example, it can be 50 rpm, 80 rpm, 100 rpm, 120 rpm, 150 rpm, 180 rpm or 200 rpm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] Preferably, the stirring speed of the second stirring step in this invention is 50-200 rpm, which allows for uniform mixing of the liquid binder and curing agent mixture with the solid soft magnetic alloy powder. If the stirring speed is too low, the raw materials will not mix evenly, resulting in excessive resin in the through-hole areas of the PCB, leading to high rigidity and detachment of the magnetic paste during drilling. Furthermore, if the magnetic paste is not mixed evenly, the curing degree of the magnetic paste will be insufficient, resulting in a lower glass transition temperature, which will affect the inductor performance obtained from the magnetic paste. Since the second stirring is carried out in a mechanical mixer, excessively high stirring speed will increase the energy consumption and wear of the mechanical mixer, thereby increasing the preparation cost of the magnetic paste.

[0039] Preferably, the second stirring time is 1 to 2 hours, for example, it can be 1 hour, 1.2 hours, 1.5 hours, 1.7 hours, 1.9 hours or 2 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] Preferably, the relative vacuum pressure of the vacuum degassing process in step (2) is -0.07 to -0.1 MPa, for example, it can be -0.07 MPa, -0.075 MPa, -0.08 MPa, -0.085 MPa, -0.09 MPa, -0.095 MPa or -0.1 MPa, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] The vacuum degassing process of this invention preferably uses a relative vacuum pressure of -0.07 to -0.1 MPa, which can remove air bubbles from the magnetic slurry to the maximum extent and prevent the formation of pores inside and on the surface of the magnetic slurry after curing, thereby preventing the magnetic permeability and loss of the magnetic slurry from deteriorating.

[0042] Preferably, the vacuum degassing treatment time is 10 to 30 minutes, for example, it can be 10 minutes, 12 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0044] (1) According to the mass fraction, 9-13 parts of adhesive and 2.85-4.61 parts of curing agent are mixed and stirred for 10-30 minutes at a speed of 50-150 rpm. Then, 100 parts of soft magnetic alloy powder are added and stirred for 1-2 hours at a speed of 50-200 rpm to obtain a semi-finished magnetic slurry.

[0045] (2) The semi-finished magnetic slurry is subjected to vacuum degassing treatment at a relative vacuum pressure of -0.07 to -0.1 MPa for 10 to 30 minutes to obtain the magnetic slurry for the inductor of the fully integrated voltage regulation module.

[0046] Thirdly, the present invention also provides the use of the magnetic paste of the fully integrated voltage regulation module inductor as described in the first aspect in the preparation of the fully integrated voltage regulation module inductor.

[0047] Compared with the prior art, the present invention has at least the following beneficial effects:

[0048] (1) The magnetic paste of the fully integrated voltage regulation module inductor provided by the present invention has low magnetic loss and suitable viscosity and good high temperature resistance. Its glass transition temperature is above 150°C, which can ensure that the inductor prepared by the magnetic paste can work normally at a high temperature.

[0049] (2) The method for preparing the inductor of the fully integrated voltage regulation module provided by the present invention is simple to operate and has a low preparation cost, making it suitable for industrial application. Detailed Implementation

[0050] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0051] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0052] The raw materials Fe-based amorphous alloy powder, bisphenol F type epoxy resin, aromatic reactive diluent TDS_REP-137, diethyltoluene diamine and isoflurone diamine in the following examples and comparative examples are all commercially available products.

[0053] Example 1

[0054] This embodiment provides a magnetic paste for the inductor of a fully integrated voltage regulation module. The magnetic paste comprises the following raw material components by mass: 100 parts of Fe-based amorphous alloy powder, 10 parts of binder, and 3.17 parts of curing agent diethyltoluenediamine. The binder is bisphenol F type epoxy resin and aromatic reactive diluent TDS_REP-137 in a mass ratio of 1:1.

[0055] The Fe-based amorphous alloy powder has a particle size D50 of 2 μm; the bisphenol F type epoxy resin has an epoxy equivalent of 180 g / eq and a viscosity of 3000 cps at 25°C; the aromatic reactive diluent has an epoxy equivalent of 130 g / eq and a viscosity of 100 cps at 25°C.

[0056] This embodiment also provides a method for preparing the magnetic paste for the inductor of the above-mentioned fully integrated voltage regulation module, the preparation method comprising the following steps:

[0057] (1) According to the mass fraction, 10 parts of adhesive and 3.17 parts of curing agent are mixed and stirred for 20 minutes at a speed of 50 rpm. Then, 100 parts of Fe-based amorphous alloy powder are added and stirred for 1 hour at a speed of 100 rpm to obtain a semi-finished magnetic slurry.

[0058] (2) The semi-finished magnetic slurry is subjected to vacuum degassing treatment at a relative vacuum pressure of -0.09MPa for 30 minutes to obtain the magnetic slurry for the inductor of the fully integrated voltage regulation module.

[0059] Example 2

[0060] This embodiment provides a magnetic paste for the inductor of a fully integrated voltage regulation module. Except for the binder (9 parts by weight) and the curing agent (2.85 parts by weight), the raw material components of the magnetic paste are the same as those in Embodiment 1.

[0061] This embodiment also provides a method for preparing the magnetic paste for the inductor of the above-mentioned fully integrated voltage regulation module, and the preparation method is the same as that in Embodiment 1.

[0062] Example 3

[0063] This embodiment provides a magnetic paste for the inductor of a fully integrated voltage regulation module. Except for the binder (13 parts by weight) and the curing agent (4.25 parts by weight), the raw material components of the magnetic paste are the same as those in Embodiment 1.

[0064] This embodiment also provides a method for preparing the magnetic paste for the inductor of the above-mentioned fully integrated voltage regulation module, and the preparation method is the same as that in Embodiment 1.

[0065] Example 4

[0066] This embodiment provides a magnetic paste for the inductor of a fully integrated voltage regulation module. Except for the mass ratio of bisphenol F epoxy resin and aromatic reactive diluent in the binder being 2:1, the raw material components of the magnetic paste are the same as those in Example 1.

[0067] This embodiment also provides a method for preparing the magnetic paste for the inductor of the above-mentioned fully integrated voltage regulation module, and the preparation method is the same as that in Embodiment 1.

[0068] Example 5

[0069] This embodiment provides a magnetic paste for the inductor of a fully integrated voltage regulation module. Except for the mass ratio of bisphenol F epoxy resin and aromatic reactive diluent in the binder being 1:2, the raw material components of the magnetic paste are the same as those in Example 1.

[0070] This embodiment also provides a method for preparing the magnetic paste for the inductor of the above-mentioned fully integrated voltage regulation module, and the preparation method is the same as that in Embodiment 1.

[0071] Example 6

[0072] This embodiment provides a magnetic paste for the inductor of a fully integrated voltage regulation module, and the raw material composition of the magnetic paste is the same as that in Embodiment 1.

[0073] This embodiment also provides a method for preparing the magnetic slurry of the inductor of the above-mentioned fully integrated voltage regulation module. The preparation method is the same as in Embodiment 1, except that the second stirring speed is replaced with 40 rpm.

[0074] Example 7

[0075] This embodiment provides a magnetic paste for the inductor of a fully integrated voltage regulation module, and the raw material composition of the magnetic paste is the same as that in Embodiment 1.

[0076] This embodiment also provides a method for preparing the magnetic paste for the inductor of the above-mentioned fully integrated voltage regulation module. The preparation method is the same as in Embodiment 1, except that the relative vacuum pressure of the vacuum degassing process is replaced with -0.05MPa.

[0077] Comparative Example 1

[0078] This comparative example provides a magnetic paste for an inductor of a fully integrated voltage regulation module. The raw material components of the magnetic paste are the same as those in Example 1, except that the binder is 5 parts by weight.

[0079] This comparative example also provides a method for preparing the magnetic paste for the inductor of the above-mentioned fully integrated voltage regulation module, the preparation method being the same as that in Example 1.

[0080] Comparative Example 2

[0081] This comparative example provides a magnetic paste for an inductor of a fully integrated voltage regulation module. The raw material components of the magnetic paste are the same as those in Example 1, except that the binder is only bisphenol F type epoxy resin.

[0082] This comparative example also provides a method for preparing the magnetic paste for the inductor of the above-mentioned fully integrated voltage regulation module, the preparation method being the same as that in Example 1.

[0083] Comparative Example 3

[0084] This comparative example provides a magnetic paste for an inductor of a fully integrated voltage regulation module. The raw material components of the magnetic paste are the same as those in Example 1, except that the binder is only an aromatic active diluent.

[0085] This comparative example also provides a method for preparing the magnetic paste for the inductor of the above-mentioned fully integrated voltage regulation module, the preparation method being the same as that in Example 1.

[0086] Comparative Example 4

[0087] This comparative example provides a magnetic paste for an inductor of a fully integrated voltage regulation module. Except for the binder, which is a conventional reactive diluent - n-butyl glycidyl ether, the raw material components of the magnetic paste are the same as those in Example 1.

[0088] This comparative example also provides a method for preparing the magnetic paste for the inductor of the above-mentioned fully integrated voltage regulation module, the preparation method being the same as that in Example 1.

[0089] 1. Viscosity tests were performed on the magnetic slurries used in the above embodiments and comparative examples:

[0090] The viscosity of the magnetic slurry was tested using a BROOKFIELD DV2T viscometer, and the results are shown in Table 1.

[0091] After the magnetic materials from the above embodiments and comparative examples were cast into the through holes of the PCB board, the PCB board filled with magnetic slurry was cured in stages according to the procedure of 80℃ / (1-2)h+100℃ / (1-2)h+125℃ / (1-2)h+150℃ / 2h.

[0092] 2. Evaluate the state of the magnetic paste in the above-described embodiments and comparative examples in the through-holes of the PCB board:

[0093] The state of the solidified magnetic paste in the through-holes of the PCB board was observed using a microscope to determine whether it was fully filled. The through-holes of the PCB used for testing were 4mm thick and had diameters of 1mm, 1.5mm, and 2mm.

[0094] 3. Evaluate the drilling results of the magnetic paste in the above-described embodiments and comparative examples in the through-holes of the PCB board:

[0095] The PCB board, filled with and cured with magnetic paste, is fixed in place, and holes are drilled into the magnetic paste portions of its through-holes. The drilled areas are then examined under a microscope for cracks, chipping, or other defects.

[0096] 4. The glass transition temperatures of the magnetic pastes in the above embodiments and comparative examples were evaluated:

[0097] The magnetic slurry was poured into an 8mm×8mm×5mm mold, allowed to solidify, and then allowed to cool naturally before demolding. The glass transition temperature was measured using a thermomechanical analyzer (TMA).

[0098] 5. The magnetic permeability of the magnetic pastes in the above embodiments and comparative examples was evaluated:

[0099] Magnetic slurry was poured into a mold with an outer diameter of 20 mm, an inner diameter of 10 mm, and a thickness of 5 mm. After curing, it was allowed to cool naturally and then demolded. The real part μ' and imaginary part μ” of the permeability at 80 MHz were measured using an Agilent E4991A analyzer, and its loss tanδ=μ” / μ' was calculated.

[0100] The state of the magnetic paste in the through-holes of the PCB board, the drilling results of the magnetic paste in the through-holes of the PCB board, the glass transition temperature and the magnetic permeability are shown in Table 1.

[0101] Table 1

[0102]

[0103] As can be seen from Table 1:

[0104] (1) As can be seen from Examples 1 to 5, the viscosity of the magnetic paste of the fully integrated voltage regulation module inductor provided by the present invention is in the range of 40,000 to 160,000 cp, which can fill the through holes of the PCB. The drilling results of the magnetic paste in the through holes of the PCB are good, and no chipping occurs. The glass transition temperature is above 150°C, and the magnetic loss can reach below 0.0230. Through the comparison of various performances of Examples 1, 2 and 3, it is found that as the proportion of binder decreases, the viscosity increases, and the real part of the magnetic permeability and the magnetic loss of the magnetic paste are improved. Through the comparison of various performances of Examples 1, 4 and 5, it is found that the higher the proportion of bisphenol F epoxy resin, the higher the viscosity of the magnetic paste.

[0105] (2) It can be seen from the combined examples 1 and 6 that the stirring speed of the second stirring in example 1 is 50 rpm, which is much lower than the stirring speed of the second stirring in example 6, which is 40 rpm. This results in the magnetic paste not being mixed evenly, which leads to excessive resin in the through-hole area of ​​the PCB and greater rigidity. The magnetic paste in the through-hole of the PCB falls off when drilling. In addition, the uneven mixing of the magnetic paste results in insufficient curing of the cured magnetic paste, which reduces the glass transition temperature.

[0106] (3) As can be seen from the combined examples 1 and 7, the relative vacuum pressure of vacuum degassing in example 1 is -0.09MPa, which is lower than the relative vacuum pressure of vacuum degassing in example 7, which is -0.05MPa. This results in the incomplete removal of air bubbles inside the magnetic slurry, which directly leads to the appearance of pores inside and on the surface of the magnetic slurry after curing, thereby deteriorating the magnetic permeability and loss of the magnetic slurry.

[0107] (4) Combining Example 1 and Comparative Example 1, it can be seen that in Example 1, the binder is 10 parts by weight, and the viscosity of the prepared magnetic slurry is 86200cp. The magnetic slurry can fill the through holes of the PCB, and the drilling results of the magnetic slurry in the through holes of the PCB are good, with no chipping, and the magnetic loss is only 0.0193. In Comparative Example 1, under the premise that the mass part of the solid raw material Fe-based amorphous alloy powder remains unchanged, the mass part of the binder is reduced, that is, the liquid in the solid is reduced, the viscosity of the obtained magnetic slurry increases, and it cannot completely fill the through holes of the PCB. At the same time, the magnetic loss also increases. This shows that the present invention limits the raw materials of the magnetic slurry to include: 100 parts of soft magnetic alloy powder, 9-13 parts of binder and 2.85-4.61 parts of curing agent by mass part, which ensures that the magnetic slurry has a suitable viscosity and low magnetic loss.

[0108] (5) Based on the comprehensive comparison of Example 1 and Comparative Examples 2-4, it can be seen that the binder in Example 1 is a bisphenol F type epoxy resin and an aromatic reactive diluent in a mass ratio of 1:1. The viscosity of the resulting magnetic slurry is 86200cp. The magnetic slurry can fill the through holes of the PCB. The drilling results of the magnetic slurry in the through holes of the PCB are good, with no chipping and a magnetic loss of only 0.0193. However, in Comparative Example 2, only bisphenol F type epoxy resin is used as the binder, and the viscosity of the magnetic slurry is too high, which causes the through holes of the PCB to not be completely filled. In Comparative Example 3, when only an aromatic reactive diluent is used as the binder, the cured magnetic slurry is brittle and chipping is very easy to occur during drilling. In Comparative Example 4, a conventional reactive diluent, n-butyl glycidyl ether, is used. The glass transition temperature of the magnetic slurry obtained is only 126.6℃, which cannot meet the requirements for working under higher temperature conditions. This shows that the magnetic slurry prepared by the binder made of bisphenol F type epoxy resin and aromatic reactive diluent has a suitable viscosity and good high temperature resistance.

[0109] In summary, the magnetic paste for the fully integrated voltage regulation module inductor provided by this invention has low magnetic loss, suitable viscosity, and good high-temperature resistance. Its glass transition temperature is above 150°C, which can ensure that the inductor prepared from this magnetic paste can operate normally at high temperatures. The preparation method is simple to operate and has low preparation cost, making it suitable for industrial application.

[0110] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A magnetic paste for a fully integrated voltage regulating module inductor, characterized in that, The raw materials of the magnetic paste, by weight, include: 100 parts of soft magnetic alloy powder, 9-13 parts of binder and 2.85-4.61 parts of curing agent; The adhesive comprises bisphenol F type epoxy resin and an aromatic reactive diluent; the aromatic reactive diluent is a compound with a benzene ring in its molecular structure and one or more epoxy groups. The viscosity of the magnetic slurry is 40,000 cps to 160,000 cps; The preparation method of the magnetic slurry includes the following steps: (1) According to the mass fraction, 9-13 parts of adhesive and 2.85-4.61 parts of curing agent are mixed, and after the first stirring, 100 parts of soft magnetic alloy powder are added for the second stirring to obtain a semi-finished magnetic slurry; the speed of the second stirring is 50-200 rpm; (2) The semi-finished magnetic slurry is subjected to vacuum degassing treatment to obtain the magnetic slurry for the inductor of the fully integrated voltage regulation module.

2. The magnetic paste according to claim 1, characterized in that, The raw materials of the magnetic paste, by weight, include: 100 parts of soft magnetic alloy powder, 10-12 parts of binder and 3.17-4.25 parts of curing agent.

3. The magnetic paste according to claim 1, characterized in that, The soft magnetic alloy powder includes Fe-based amorphous alloy powder.

4. The magnetic paste according to claim 1, characterized in that, The particle size D50 of the soft magnetic alloy powder is 1~4μm.

5. The magnetic paste according to claim 1, characterized in that, The mass ratio of bisphenol F epoxy resin to aromatic reactive diluent in the adhesive is 2:1 to 1:

2.

6. The magnetic paste according to claim 1, characterized in that, The epoxy equivalent of the bisphenol F type epoxy resin is 150~190 g / eq.

7. The magnetic paste according to claim 6, characterized in that, The bisphenol F type epoxy resin has a viscosity of 2000~5000 cps at 25°C.

8. The magnetic paste according to claim 1, characterized in that, The epoxy equivalent of the aromatic reactive diluent is 100~140 g / eq.

9. The magnetic paste according to claim 8, characterized in that, The viscosity of the aromatic reactive diluent at 25°C is 50~500 cps.

10. The magnetic paste according to claim 1, characterized in that, The curing agent includes diethyltoluene diamine and / or isoflurane diamine.

11. A method for preparing magnetic paste for the inductor of a fully integrated voltage regulation module as described in any one of claims 1 to 10, characterized in that, The preparation method includes the following steps: (1) According to the mass fraction, 9-13 parts of adhesive and 2.85-4.61 parts of curing agent are mixed, and after the first stirring, 100 parts of soft magnetic alloy powder are added for the second stirring to obtain a semi-finished magnetic slurry; the speed of the second stirring is 50-200 rpm; (2) The semi-finished magnetic slurry is subjected to vacuum degassing treatment to obtain the magnetic slurry for the inductor of the fully integrated voltage regulation module.

12. The preparation method according to claim 11, characterized in that, Step (1) The first stirring speed is 50~150 rpm.

13. The preparation method according to claim 12, characterized in that, The first stirring time is 10~30 minutes.

14. The preparation method according to claim 11, characterized in that, The second stirring time is 1~2 hours.

15. The preparation method according to claim 11, characterized in that, The relative vacuum pressure of the vacuum degassing process in step (2) is -0.07 to -0.1 MPa.

16. The preparation method according to claim 15, characterized in that, The vacuum degassing treatment takes 10 to 30 minutes.

17. The preparation method according to claim 11, characterized in that, The preparation method includes the following steps: (1) According to the mass fraction, 9-13 parts of adhesive and 2.85-4.61 parts of curing agent are mixed and stirred for 10-30 minutes at a speed of 50-150 rpm. Then, 100 parts of soft magnetic alloy powder are added and stirred for 1-2 hours at a speed of 50-200 rpm to obtain a semi-finished magnetic slurry. (2) The semi-finished magnetic slurry is subjected to vacuum degassing treatment at a relative vacuum pressure of -0.07 to -0.1 MPa for 10 to 30 minutes to obtain the magnetic slurry for the inductor of the fully integrated voltage regulation module.

18. The use of a magnetic paste for a fully integrated voltage regulation module inductor as described in any one of claims 1 to 10 in the fabrication of a fully integrated voltage regulation module inductor.

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