Preparation Method For Spherical Or Angular Powder Filler, Spherical Or Angular Powder Filler Obtained Thereby, And Application Thereof

Abstract

A preparation method for a spherical or angular powder filler, comprising: providing spherical or angular siloxane comprising a T unit, wherein the T unit is R.sub.1SiO.sub.3−, and R.sub.1 is a hydrogen atom or an organic group which can be independently selected from carbon atoms 1-18; and performing heat treatment on the spherical or angular siloxane under an inert gas atmosphere or atmospheric atmosphere, the heat treatment temperature being between 250 degrees and 650 degrees, so that silicon hydroxyl groups in the spherical or angular siloxane are condensed to obtain the spherical or angular powder filler. In the unit T of the spherical or angular powder filler, the content of the unit without containing a hydroxyl group in the total unit is greater than or equal to 95%, and the content of the unit containing one hydroxyl group in the total unit is less than or equal to 5%. Also disclosed are the spherical or angular powder filler obtained by the preparation method, and application thereof. The spherical or angular powder filler has low permittivity, low water absorption and low radioactivity.

Claims

1. A preparation method for a spherical or angular powder filler, comprising the steps of: S1, providing spherical or angular siloxane comprising a T unit, wherein the T unit=R1 SiO3−, and R1 is a hydrogen atom or an organic group which can be independently selected from carbon atoms 1-18; and S2, performing heat treatment on the spherical or angular siloxane under an inert gas atmosphere or atmospheric atmosphere, the heat treatment temperature being between 250 degrees and 650 degrees, so that silicon hydroxyl groups in the spherical or angular siloxane are condensed to obtain the spherical or angular powder filler, wherein in the unit T of the spherical or angular powder filler, the content of the unit without containing a hydroxyl group in the total unit is greater than or equal to 95%, and the content of the unit containing one hydroxyl group in the total unit is less than or equal to 5%.

2. The preparation method according to claim 1, wherein the spherical or angular siloxane further comprises a Q unit, D unit and/or M unit, wherein Q unit=SiO4−, D unit=R2R3SiO2−, M unit=R4R5R6SiO2−, each of R2, R3, R4, R5, and R6 is a hydrogen atom or a hydrocarbyl which can be independently selected from carbon atoms 1-18.

3. The preparation method according to claim 1, wherein the spherical or angular siloxane further comprises silica particles.

4. The preparation method according to claim 1, wherein the preparation method further comprises treating the powder filler on surface by a treatment agent, wherein the treatment agent includes a silane coupling agent, which is (R7)a(R8)bSi(M)4-a-b, wherein each of R7, R8 is a hydrogen atom, a hydrocarbyl which can be independently selected from carbon atoms 1-18, or a hydrocarbyl which can be independently selected from carbon atoms 1-18 replaced by functional groups, wherein the functional group is at least one group selected from following organic functional groups: vinyl, allyl, styryl, epoxygroup, aliphatic amino, aromatic amino, methacryloxypropyl, acryloxypropyl, ureidopropyl, chloropropyl, mercaptopropyl, polysulfide group, isocyanate propyl, M is an alkoxy group comprising 1-18 carbon atoms or a halogen atom, a=0, 1, 2 or 3, b=0, 1, 2 or 3, and a+b=1, 2 or 3; and/or the treatment agent includes disilazane, which is (R9R10R11)SiNHSi(R12R13R14), wherein each of R9, R10, R11, R12, R13, R14 is a hydrogen atom or a hydrocarbyl which can be independently selected from carbon atoms 1-18.

5. The preparation method according to claim 1, wherein the preparation method comprises removing coarse oversize particles above 1, 3, 5, 10, 20, 45, 55 or 75 microns in the spherical or angular powder filler by dry or wet sieving or inertial classification.

6. The preparation method according to claim 1, wherein the spherical or angular powder filler has a particle size of 0.1-50 microns.

7. The preparation method according to claim 6, wherein the spherical or angular powder filler of different particle sizes is tightly packed and graded in resin to form a composite material.

8. The preparation method according to claim 7, wherein the composite material is suitable for semiconductor packaging materials, circuit boards and intermediate semi-finished products thereof, and semi-cured sheets or copper clad laminates of high-frequency high-speed circuit boards.

Description

DESCRIPTION OF THE ENABLING EMBODIMENT

[0030] The preferred embodiments of the present invention are given below and described in detail.

[0031] The detection methods involved in the following embodiments include: The average particle size was measured by a laser particle size distribution instrument HORIBA LA-700, and the solvent was isopropanol.

[0032] The content of uranium and thorium was measured by Agilent 7700X ICP-MS. The sample was prepared by total dissolution in hydrofluoric acid after burning at 800 degrees.

[0033] The weight loss after heating at 200 degrees for 2 hours was weighed by an analytical balance, and the heated sample was cooled in a dry air container and then weighed. The heated sample absorbed water to gain weight when placed in the atmosphere, indicating that the weight loss after heating was the water absorbed by the siloxane. The sample before the test was placed in the atmosphere for more than 1 hour to allow the sample to absorb water in the atmosphere to reach a saturated state. The atmosphere mentioned here refers to the natural atmosphere in the subtropical area.

[0034] The content of the Q, T, D, or M unit was measured by solid .sup.28Si-NMR nuclear magnetic resonance spectrum of JEOL ECS-400 Nuclear magnetic resonance instrument, wherein the Q unit content was calculated from the peak integrated area between −80 ppm and −120 ppm, the T unit content was calculated from the peak integrated area between −30 ppm and −80 ppm, the D unit content was calculated from the peak integrated area between −10 ppm and −30 ppm; and the M unit content was calculated from the peak integrated area between +20 ppm and −10 ppm; referring to Separation and Purification Technology Volume 25, Issues 1-3, 1 Oct. 2001, Pages 391-397, 29Si NMR and Si2p XPS correlation in polysiloxane membranes prepared by plasma enhanced chemical vapor deposition. The percentage of T.sub.1, T.sub.2, T.sub.3 content is based on: the area in the range of −42˜−52 ppm (excluding −52 ppm) is attributed to T.sub.1, the area in the range of −52˜−62 ppm (excluding −62 ppm) is attributed to T.sub.2, the area in the range of −62˜−75 ppm is attributed to T.sub.3, and the integrated peak area in the range of −30 to −80 ppm is calculated as the denominator.

[0035] The permittivity was measured by KEYCOM permittivity or permittivity loss measuring device Model No.DPS18 in perturbation method and sample hole block-shaped cavity resonance method.

[0036] In this text, temperature degree refers to “degrees Celsius”, that is, ° C.

[0037] Referring to methods of “Spherical Silicone Resin Micropowder”, Huang Wenrun, Organic Silicone Materials, 2007, 21(5)294-299 and PCT/CN2018/124685, the spherical siloxane of different compositions in Examples and Comparative Examples was prepared for subsequent heat treatment.

[0038] Methyltrichlorosilane or methyltrimethoxysilane was added into water to provide a white precipitate. After being washed with deionized water, the precipitate was ground by a sand mill to a fine powder of 2 microns in Examples and Comparative Examples for subsequent heat treatment.

[0039] In addition, methyltrichlorosilane or methyltrimethoxysilane was mixed with silica, and the mixture was added into water to provide a white precipitate. After being washed with deionized water, the precipitate was ground by a sand mill to a fine powder of 2 microns in Examples and Comparative Examples for subsequent heat treatment.

Embodiment 1

[0040] The spherical siloxane of 100% T unit (R.sub.1 is methyl) with an average particle size of 2 microns was heat-treated at different temperatures in an air or nitrogen atmosphere. The treated powder was mixed with 1% vinyltrimethoxysilane, the mixture was heated at 130° C. for 3 hours, and the powder was separated by cyclone to remove coarse oversize particles above 10 microns to obtain samples of Examples and Comparative Examples. The analysis results of the samples were listed in Table 1.

TABLE-US-00001 TABLE 1 Composition of Spherical Powder 200-degree Filler Average Heat Heat volatile T.sub.3 unit T.sub.2 unit Particle Treatment Treatment moisture content content Size Temperature Time content Permittivity % % μm ° C. h Atmosphere % 500 MHz Example 1 95 5 2.0 250 72 air 0.09 2.8 Example 2 97 3 2.0 450 20 nitrogen 0.05 2.6 Example 3 99.5 0.5 2.0 650  6 nitrogen 0.04 2.6 Comparative 87 13 2.0 120 72 air 1.2  3.2 Example 1 Comparative 94 6 2.0 200 20 air 0.1  2.9 Example 2 Comparative 0 0 2.0 650 72 air 0.05 3.9 Example 3

[0041] Obviously, for each of the samples obtained according to Examples 1-3, the permittivity was less than 3 and the 200-degree volatile moisture content was less than 0.1%, meeting the requirement of low permittivity (less signal delay) of the filler in the 5G era. The water absorption and permittivity were too high of each of the samples of high T.sub.2 content obtained according to Comparative Examples 1-2, and the permittivity was too high since the T unit was all oxidized to Q unit (that is silicon dioxide) according to Comparative Example 3, which do not belong to the scope of the present invention.

Embodiment 2

[0042] The spherical siloxane of 97% T unit (R.sub.1 is methyl) and 3% Q unit with an average particle size of 2 microns was heat-treated in a nitrogen atmosphere. The treated powder was not treated with any treatment agent for surface treatment but was directly separated by cyclone to remove coarse oversize particles above 10 microns to obtain the sample of Example 4. The analysis results of the sample were listed in Table 2.

TABLE-US-00002 TABLE 2 Composition of Spherical Powder 200-degree Filler Average Heat Heat volatile T.sub.3 unit T.sub.2 unit Particle Treatment Treatment moisture content content Size Temperature Time content Permittivity % % μm ° C. h Atmosphere % 500 MHz Example 4 99.6 0.4 2.0 550 20 nitrogen 0.02 2.8

[0043] Obviously, for the sample obtained according to Example 4, the permittivity was less than 3 and the 200-degree volatile moisture content was less than 0.1%, meeting the requirement of low permittivity (less signal delay) of the filler in the 5G era.

Embodiment 3

[0044] The spherical siloxane of 97% T unit (R.sub.1 is methyl) and 3% D unit (each of R.sub.2, R.sub.3 is methyl) with an average particle size of 2 microns was heat-treated in an air or nitrogen atmosphere. The treated powder was treated with 2% hexamethyldisilazane, the mixture was heated at 130° C. for 3 hours, and the powder was separated by cyclone to remove coarse oversize particles above 10 microns to obtain the sample of Example 5. The analysis results of the sample were listed in Table 3.

TABLE-US-00003 TABLE 3 Composition of 200-degree Spherical Average Heat Heat volatile Powder Filler Particle Treatment Treatment moisture T unit D unit Size Temperature Time content Permittivity wt % wt % μm ° C. h Atmosphere % 500 MHz Example 5 99.3 0.7 2.0 550 20 nitrogen 0.06 2.5

[0045] Obviously, for the sample obtained according to Example 5, the permittivity was less than 3 and the 200-degree volatile moisture content was less than 0.1%, meeting the requirement of low permittivity (less signal delay) of the filler in the 5G era.

Embodiment 4

[0046] Methyltrimethoxysilane was mixed with silica, and the mixture was added into water to provide a white precipitate. After being washed with deionized water, the precipitate was ground by a sand mill to a fine powder of 2 microns. The angular siloxane of 70% T unit (R.sub.1 is methyl) and 30% fine silica powder (fumed white carbon) with an average particle size of 2 microns was heat-treated at different temperatures in an air or nitrogen atmosphere. The treated powder was mixed and treated with 5% dimethyldimethoxysilane, and then heated at 130° C. for 3 hours. The powder was separated by cyclone to remove coarse oversize particles above 10 microns to obtain the sample of Example 6. The analysis results of the sample were listed in Table 4.

TABLE-US-00004 TABLE 4 Composition of Spherical Powder 200-degree Filler Average Heat Heat volatile T.sub.3 T.sub.2 Particle Treatment Treatment moisture content content Size Temperature Time content Permittivity % % μm ° C. h Atmosphere % 500 MHz Example 6 99 1 2.0 550 20 nitrogen 0.05 2.9

[0047] Obviously, for the sample obtained according to Example 6, the permittivity was less than 3 and the 200-degree volatile moisture content was less than 0.1%, meeting the requirement of low permittivity (less signal delay) of the filler in the 5G era.

Embodiment 5

[0048] The spherical siloxane of 100% T unit (R.sub.1 is methyl) with an average particle size of 2 microns was heat-treated in a nitrogen atmosphere. The treated powder was mixed with 2% vinyltrimethoxysilane and 1% hexamethyldisilazane, the mixture was heated at 130° C. for 3 hours, and the powder was separated by cyclone to remove coarse oversize particles above 10 microns to obtain sample of Example 7. The analysis results of the samples were listed in Table 5.

[0049] The spherical siloxane of 100% T unit (R.sub.1 is methyl) with an average particle size of 2 microns was heat-treated in a nitrogen atmosphere. The treated powder was mixed with 2% methyltrimethoxysilane and 1% hexamethyldisilazane, the mixture was heated at 130° C. for 3 hours, and the powder was separated by cyclone to remove coarse oversize particles above 10 microns to obtain sample of Example 8. The analysis results of the samples were listed in Table 5.

TABLE-US-00005 TABLE 5 Composition of Spherical Powder 200-degree Filler Average Heat Heat volatile T.sub.3 T.sub.2 Particle Treatment Treatment moisture content content Size Temperature Time content Permittivity % % μm ° C. h Atmosphere % 500 MHz Example 7 99 1 2.0 550 20 nitrogen 0.04 2.6 Example 8 99 1 2.0 550 20 nitrogen 0.05 2.7

[0050] Obviously, for each of samples obtained according to Examples 7-8, the permittivity was less than 3 and the 200-degree volatile moisture content was less than 0.1%, meeting the requirement of low permittivity (less signal delay) of the filler in the 5G era.

Embodiment 6

[0051] The spherical siloxane of 100% T unit (R.sub.1 is methyl) with different average particle sizes was heat-treated at different temperatures for different times in a nitrogen atmosphere to obtain samples of Examples 9-13. The analysis results of the samples were listed in Table 6.

TABLE-US-00006 TABLE 6 Composition of Spherical Powder 200-degree Filler Average Heat Heat volatile T.sub.3 T.sub.2 Particle Treatment Treatment moisture content content Size Temperature Time content Permittivity % % μm ° C. h Atmosphere % 500 MHz Example 9 99.7 0.3 0.5 550 20 nitrogen 0.06 2.8 Example 10 99.7 0.3 2.0 550 20 nitrogen 0.04 2.6 Example 11 99.7 0.3 10 550 20 nitrogen 0.04 2.6 Example 12 99.9 0.1 30 550 20 nitrogen 0.03 2.6 Example 13 99.99 <0.1 50 550 20 nitrogen 0.02 2.6

[0052] Obviously, for each of samples obtained according to Examples 9-13, the permittivity was less than 3 and the 200-degree volatile moisture content was less than 0.1%, meeting the requirement of low permittivity (less signal delay) of the filler in the 5G era. In addition, a low-viscosity filler can be obtained by the tightly packed and graded powders of Examples 9-13.

Embodiment 7

[0053] Methyltrichlorosilane was added into water to provide a white precipitate. After being washed with deionized water, the precipitate was ground by a sand mill to a fine powder of 2 microns. After filtration and drying, the heat treatment was performed in a nitrogen atmosphere. The treated powder was mixed and treated with 4% hexamethyldisilazane, and then heated at 130° C. for 3 hours. The powder was separated by cyclone to remove coarse oversize particles above 10 microns to obtain the sample of Example 14. The analysis results of the sample were listed in Table 7.

TABLE-US-00007 TABLE 7 Composition of Spherical Powder 200-degree Filler Average Heat Heat volatile T.sub.3 T.sub.2 Particle Treatment Treatment moisture content content Size Temperature Time content Permittivity % % μm ° C. h Atmosphere % 500 MHz Example 14 99 1 2.0 550 20 nitrogen 0.05 2.8

[0054] Obviously, for the sample obtained according to Example 14, the permittivity was less than 3 and the 200-degree volatile moisture content was less than 0.1%, meeting the requirement of low permittivity (less signal delay) of the filler in the 5G era.

[0055] It should be understood that samples of above Examples 1-14 can be vertex cut to remove coarse oversize particles. Specifically, coarse oversize particles above 1, 3, 5, 10, 20, 45, 55, or 75 m in the spherical or angular powder filler can be removed by dry or wet sieving or inertial classification according to the size of the semiconductor chip. Further, Uranium or thorium content of samples of above Examples 1-14 was less than 0.5 ppb, wherein the samples were dissolved in hydrofluoric acid and measured by ICP-MS.

[0056] The foregoing description refers to preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Various changes can be made to the foregoing embodiments of the present invention. That is to say, all simple and equivalent changes and modifications made in accordance with the claims of the present invention and the content of the description fall into the protection scope of the patent of the present invention. What is not described in detail in the present invention is conventional technical content.