Silicon dioxide filler for chip-level bottom filling glue and its preparation method and application

Abstract

The present invention relates to a silicon dioxide filler for chip-level bottom filling glue and a preparation method and application thereof. The preparation method comprises the following steps: mixing a cosolvent solution with a silicon source compound to obtain a solution A; mixing a catalyst aqueous solution with the obtained solution A to obtain a suspension; solid-liquid separation of the obtained suspension, drying to obtain a powder A; calcining the obtained powder A to obtain the chip-level SiO2 filler. The chip-level silicon dioxide filler prepared by the preparation method of the present invention has high purity, high sphericity, low impurity ion content, and a particle size distribution that meets the requirements of flip chip packaging. In addition, by regulating the ratio of the cosolvent, the catalyst and the silicon source compound, the average particle size and the cut-off point of the prepared silicon dioxide can be controlled, without the need for subsequent classification, screening and grading process operations.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor technology and relates to silicon dioxide, in particular to a silicon dioxide filler for chip-level bottom filling glue and a preparation method and application thereof. Background Art

[0002] Silicon dioxide (SiO2) is widely used as an inorganic filler in chip-level bottom filling glue, which is crucial for stress matching, mechanical protection and reliability after chip packaging. As electronic equipment gradually develops towards thinness, high integration and multi-function, the packaging form of integrated circuits (ICs) has begun to transition from 2D packaging to 2.1D, 2.5D and 3D packaging. Under the development trend of high-density interconnection, the spacing between chips, between micro-bumps, and between chips and substrates is getting narrower and narrower, which puts forward new requirements for the particle size, impurity elements and radioactive element content of SiO2. At present, the methods for preparing SiO2 include melting method, explosion method and chemical synthesis method. Although they can prepare SiO2 of different particle sizes, there are still certain disadvantages.

[0003] The melting method for producing SiO2 uses crystalline silicon dioxide as raw material. Before preparing SiO2, the crystalline silicon dioxide needs to be crushed, ultra-finely ground, screened and purified. The purified powder is then sent into a high-temperature field generated by combustible gas-oxygen. After high-temperature melting, the surface tension of the powder is regulated during the cooling process by controlling the conditions, and finally it is cooled and solidified into spherical SiO2.

[0004] However, the average particle size of SiO2 obtained by the melting method is large and the sphericity is not high. In addition, since the crystalline silicon dioxide comes from natural quartz ore, the content of radioactive element U is relatively high.

[0005] The combustion and explosion method uses ultrafine silicon powder as raw material. Before preparing spherical SiO2, the silicon powder needs to be ultrafinely crushed and screened. The combustion and explosion method uses a burner to burn combustible gases such as methane, propane, hydrogen or acetylene in an oxygen-containing atmosphere to form a flame, and at the same time, ultrafine silicon powder is sent into the flame to form a dust cloud, which triggers the combustion and explosion to obtain spherical SiO2 ultrafine particles. The SiO2 obtained by the combustion and explosion method has a high sphericity and a smooth surface, but ultrafine silicon powder is prone to dust explosions, and has extremely high safety requirements for space and equipment. Moreover, if spherical SiO2 with a specified particle size distribution is to be obtained, the SiO2 product needs to be reclassified, screened and graded, and the production process is relatively cumbersome.

[0006] The chemical synthesis method uses silicon compounds as raw materials, and obtains high-purity spherical SiO2 through nucleation and growth processes under the action of dispersants, control agents and catalysts. The chemical synthesis method can control the morphology and particle size of SiO2 by controlling factors such as reaction temperature, raw material ratio and addition order. At the same time, the content of impurity ions and radioactive elements in SiO2 can be further reduced by purifying the raw materials.

[0007] The present invention provides a method for preparing SiO2 based on a chemical synthesis method. The SiO2 obtained by the preparation method has high purity, high sphericity, low impurity ion content, and a particle size distribution that meets the requirements of flip chip packaging scenarios. Moreover, the preparation method provided by the present invention can flexibly control the average particle size and cut-off point of SiO2 without the need for subsequent classification, screening and grading process treatment. Summary of the invention

[0008] The object of the present invention is to provide a silicon dioxide filler for chip-level bottom filling glue and a preparation method and application thereof. The chip-level silicon dioxide filler obtained by the preparation method has high purity and good sphericity, and the preparation conditions are easy to control, so it is convenient to control the average particle size of the final chip-level silicon dioxide filler.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for preparing a silicon dioxide filler for chip-level underfill, the preparation method comprising the following steps:

[0011] (1) mixing the co-solvent solution and the silicon source compound to obtain a solution A;

[0012] (2) mixing the catalyst aqueous solution with the solution A obtained in step (1) to obtain a suspension;

[0013] (3) The suspension obtained in the solid-liquid separation step (2) is dried to obtain powder A;

[0014] (4) calcining the powder A obtained in step (3) to obtain the chip-grade silica filler.

[0015] The preparation method provided by the present invention first mixes a silicon source compound and a co-solvent, and under the action of a catalyst in a catalyst aqueous solution, the silicon source compound is gradually hydrolyzed and condensed to obtain a stable sol system; and the gel formed by sol polymerization is subjected to solid-liquid separation, drying and sintering to form a chip-grade silicon dioxide with high purity and good sphericity, and the particle size distribution meets the packaging requirements of the flip chip.

[0016] Preferably, the co-solvent solution in step (1) comprises a co-solvent and water in a mass ratio of (10-50):(10-100), for example, it can be 50:10, 50:25, 50:30, 50:40, 10:10, 10:20, 10:30, 10:40, 10:50, 10:60, 10:70, 10:80, 10:90 or 10:100, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] Preferably, the co-solvent comprises any one of methanol, ethanol, isopropanol or cyclohexane or a combination of at least two thereof, typical but non-limiting combinations comprising a combination of methanol and ethanol, a combination of ethanol and isopropanol, a combination of isopropanol and cyclohexane, a combination of methanol, ethanol and isopropanol, a combination of ethanol, isopropanol and cyclohexane, or a combination of methanol, ethanol, isopropanol and cyclohexane.

[0018] Preferably, the mass ratio of the co-solvent solution to the silicon source compound in step (1) is (1-50):1, for example, it can be 1:1, 5:1, 10:1, 20:1, 30:1, 40:1 or 50:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, the silicon source compound in step (1) includes any one of organosilicon, siloxane or silicate, or a combination of at least two of them, for example, a combination of organosilicon and siloxane, a combination of siloxane and silicate, a combination of organosilicon and silicate, or a combination of organosilicon, siloxane and silicate.

[0020] Preferably, the organic silicon comprises any one of vinyl trimethoxysilane, vinyl triethoxysilane, (3-mercaptopropyl) trimethoxysilane, allyl trimethoxysilane, 3-glycidyloxypropyl trimethoxysilane or dodecyl trimethoxysilane, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of vinyl trimethoxysilane and vinyl triethoxysilane, a combination of (3-mercaptopropyl) trimethoxysilane and allyl trimethoxysilane, a combination of 3-glycidyloxypropyl trimethoxysilane and dodecyl trimethoxysilane. trimethoxysilane and dodecyltrimethoxysilane, a combination of vinyltrimethoxysilane, vinyltriethoxysilane and (3-mercaptopropyl)trimethoxysilane, a combination of allyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane and dodecyltrimethoxysilane, or a combination of vinyltrimethoxysilane, vinyltriethoxysilane, (3-mercaptopropyl)trimethoxysilane, allyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane and dodecyltrimethoxysilane.

[0021] Preferably, the siloxane includes any one of tetramethoxysilane, tetraethoxysilane or tetrapropoxysilane or a combination of at least two thereof, and typical but non-limiting combinations include a combination of tetramethoxysilane and tetraethoxysilane, a combination of tetraethoxysilane and tetrapropoxysilane, a combination of tetramethoxysilane and tetrapropoxysilane, or a combination of tetramethoxysilane, tetraethoxysilane and tetrapropoxysilane.

[0022] Preferably, the silicate comprises sodium silicate.

[0023] Preferably, the mixing temperature in step (2) is 30-60°C, for example, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C or 60°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] Preferably, the mass ratio of the catalyst aqueous solution to the silicon source compound in step (2) is (1-20):1, for example, it can be 1:1, 3:1, 5:1, 8:1, 10:1, 12:1, 15:1, 18:1 or 20:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the concentration of the catalyst aqueous solution in step (2) is 0.1-20wt%, for example, it can be 0.1wt%, 1wt%, 3wt%, 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 16wt%, 18wt% or 20wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the catalyst aqueous solution in step (2) comprises any one of an inorganic acid aqueous solution, an inorganic base aqueous solution or an organic acid aqueous solution, or a combination of at least two of them.

[0027] Preferably, the mixing in step (2) comprises stirring and mixing until a suspension is obtained, and then continuing to stir for 10-300 min, for example, 10 min, 30 min, 50 min, 60 min, 80 min, 100 min, 120 min, 150 min, 160 min, 180 min, 200 min, 210 min, 240 min, 250 min, 270 min, 280 min or 300 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the stirring and mixing rotation speed is 150-250 rpm, for example, it can be 150 rpm, 160 rpm, 180 rpm, 200 rpm, 210 rpm, 240 rpm or 250 rpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the suspension obtained in step (2) is a white suspension.

[0030] Preferably, the solid-liquid separation method in step (3) comprises any one of filter pressing, centrifugation or sedimentation, or a combination of at least two of them. Typical but non-limiting combinations include a combination of filter pressing and centrifugation, a combination of centrifugation and sedimentation, a combination of filter pressing and sedimentation, or a combination of filter pressing, centrifugation and sedimentation.

[0031] Preferably, the drying temperature in step (3) is 30-220°C, for example, it can be 30°C, 50°C, 60°C, 80°C, 100°C, 120°C, 150°C, 160°C, 180°C, 200°C or 220°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the drying time in step (3) is 1-24 h, for example, 1 h, 2 h, 3 h, 5 h, 6 h, 8 h, 10 h, 12 h, 15 h, 16 h, 18 h, 20 h, 21 h or 24 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] The present invention achieves the removal of physically adsorbed water by drying after solid-liquid separation, thereby obtaining powder A.

[0034] Further preferably, the preparation method includes washing the obtained solid after solid-liquid separation to remove impurities present in the silicon source compound, thereby reducing the purity requirement for the silicon source compound and ensuring the purity of the final chip-grade silica filler.

[0035] Preferably, the temperature of the calcination treatment in step (4) is 500-1300°C, for example, it can be 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C, 1200°C or 1300°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the calcination time in step (4) is 10-300 min, for example, 10 min, 30 min, 50 min, 60 min, 80 min, 100 min, 120 min, 150 min, 160 min, 180 min, 200 min, 210 min, 240 min, 250 min, 270 min, 280 min or 300 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0037] Preferably, the calcination device used in step (4) comprises any one of a tube furnace, a box furnace, a tunnel furnace, a push plate furnace or a track furnace, or a combination of at least two of them.

[0038] The present invention calcines powder A to remove organic matter in powder A and densifies powder A to obtain dense spherical silicon dioxide, which is the chip-level silicon dioxide filler of the present invention.

[0039] As a preferred technical solution of the preparation method described in the first aspect of the present invention, the preparation method comprises the following steps:

[0040] (1) mixing a co-solvent solution and a silicon source compound in a mass ratio of (1-50):1 to obtain a solution A; the co-solvent solution comprises a co-solvent and water in a mass ratio of (10-50):(10-100);

[0041] (2) stirring the catalyst aqueous solution and the solution A obtained in step (1) at 30-60° C. at a speed of 150-250 rpm until a white suspension is obtained, and then continuing to stir for 10-300 min; the mass ratio of the catalyst aqueous solution to the silicon source compound is (1-20):1;

[0042] (3) The suspension obtained in the solid-liquid separation step (2) is dried at 30-220° C. for 1-24 h to obtain powder A;

[0043] (4) calcining the powder A obtained in step (3) at 500-1300° C. to obtain the chip-grade silica filler, with the calcination time being 10-300 min.

[0044] In a second aspect, the present invention provides a silicon dioxide filler for chip-level bottom filling glue, and the chip-level silicon dioxide filler is obtained by the preparation method described in the first aspect.

[0045] The silicon dioxide filler for chip-level bottom filling glue provided by the invention has a purity of ≥99.9wt% and a sphericity of ≥98%; its particle size distribution D50 is 0.3-8μm and D100 is 1-20μm, meeting the requirements of flip chip packaging.

[0046] In a third aspect, the present invention provides an application of a silicon dioxide filler for chip-level bottom filling glue, wherein the silicon dioxide filler for chip-level bottom filling glue is used for chip packaging.

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

[0048] The silicon dioxide filler for chip-level bottom filling glue prepared by the preparation method of the present invention has a purity of ≥99.9%, a sphericity of 98≥%, and a low impurity ion content; and a particle size distribution D50 of 0.3-8μm and D100 of 1-20μm, which meets the requirements of flip chip packaging. In addition, by regulating the ratio of the cosolvent, the catalyst and the silicon source compound, the average particle size and the cut-off point of the prepared silicon dioxide can be controlled, without the need for subsequent classification, screening and grading process operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a scanning electron microscope image of the chip-level silica filler obtained in Example 1 of the present invention;

[0050] Figure 2 This is a particle size distribution diagram of the chip-grade silica filler obtained in Example 1 of the present invention;

[0051] Figure 3 This is a scanning electron microscope image of the chip-level silica filler obtained in Example 2 of the present invention;

[0052] Figure 4 This is a particle size distribution diagram of the chip-grade silica filler obtained in Example 2 of the present invention. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] Example 1

[0055] This embodiment provides a method for preparing a chip-level silica filler, the preparation method comprising the following steps:

[0056] (1) mixing a co-solvent solution and a silicon source compound in a mass ratio of 30:1 to obtain a solution A; the co-solvent solution is composed of a co-solvent and deionized water in a mass ratio of 2:5; the co-solvent is cyclohexane; and the silicon source compound is (3-mercaptopropyl)trimethoxysilane;

[0057] (2) stirring and mixing a 10 wt % catalyst aqueous solution and the solution A obtained in step (1) at 40° C. and 200 rpm until a white suspension is obtained, and then stirring is continued for 120 min; the catalyst aqueous solution is ammonia water; and the mass ratio of the catalyst aqueous solution to the silicon source compound is 10:1;

[0058] (3) Centrifuging the white suspension obtained in step (2) to obtain a white muddy substance, drying at 60° C. for 14 h to remove physically adsorbed water to obtain powder A;

[0059] (4) The powder A obtained in step (3) is calcined in a tunnel furnace, and the temperature in the tunnel furnace rises to 1000° C. in 100 minutes. Powder A stays in the tunnel furnace for 120 minutes. During this process, organic matter in powder A is removed and powder A is densified to obtain the chip-grade silica filler.

[0060] The SEM image of the chip-grade silica filler obtained in this example is as follows: Figure 1 The particle size distribution diagram is shown in Figure 2 shown.

[0061] Example 2

[0062] This embodiment provides a method for preparing a chip-level silica filler, the preparation method comprising the following steps:

[0063] (1) mixing a co-solvent solution and a silicon source compound in a mass ratio of 15:1 to obtain a solution A; the co-solvent solution is composed of a co-solvent and deionized water in a mass ratio of 1:5; the co-solvent is cyclohexane; and the silicon source compound is (3-mercaptopropyl)trimethoxysilane;

[0064] (2) stirring a 5 wt % catalyst aqueous solution and the solution A obtained in step (1) at 35° C. and 180 rpm until a white suspension is obtained, and then stirring is continued for 200 min; the catalyst aqueous solution is ammonia water; and the mass ratio of the catalyst aqueous solution to the silicon source compound is 15:1;

[0065] (3) filtering the white suspension obtained in step (2) to obtain white blocks, drying at 120° C. for 12 h to remove physically adsorbed water to obtain powder A;

[0066] (4) The powder A obtained in step (3) is calcined in a box-type furnace. The temperature in the tunnel furnace rises to 1100° C. in 120 min, and the powder A stays therein for 90 min. During this process, the organic matter in the powder A is removed and the powder A is densified to obtain the chip-grade silica filler.

[0067] The SEM image of the chip-grade silica filler obtained in this example is as follows: Figure 3The particle size distribution diagram is shown in Figure 4 shown.

[0068] Example 3

[0069] This embodiment provides a method for preparing a chip-level silica filler, the preparation method comprising the following steps:

[0070] (1) mixing a co-solvent solution and a silicon source compound in a mass ratio of 40:1 to obtain a solution A; the co-solvent solution is composed of a co-solvent and deionized water in a mass ratio of 1:8; the co-solvent is cyclohexane; and the silicon source compound is (3-mercaptopropyl)trimethoxysilane;

[0071] (2) stirring and mixing a 15 wt % catalyst aqueous solution and the solution A obtained in step (1) at 210 rpm at 50° C. until a white suspension is obtained, and then stirring is continued for 300 min; the catalyst aqueous solution is ammonia water; and the mass ratio of the catalyst aqueous solution to the silicon source compound is 5:1;

[0072] (3) filtering the white suspension obtained in step (2) to obtain white blocks, drying at 180° C. for 9 h to remove physically adsorbed water to obtain powder A;

[0073] (4) The powder A obtained in step (3) is calcined in a push plate furnace, and the temperature in the tunnel furnace rises to 1000° C. in 240 minutes, and the powder A stays therein for 300 minutes. During this process, the organic matter in the powder A is removed, and the powder A is densified to obtain the chip-grade silica filler.

[0074] Example 4

[0075] This embodiment provides a method for preparing a chip-level silica filler, the preparation method comprising the following steps:

[0076] (1) mixing a co-solvent solution and a silicon source compound in a mass ratio of 1:1 to obtain a solution A; the co-solvent solution is composed of a co-solvent and deionized water in a mass ratio of 1:10; the co-solvent is cyclohexane; and the silicon source compound is (3-mercaptopropyl)trimethoxysilane;

[0077] (2) stirring at 60° C. and 150 rpm to mix a 0.1 wt % catalyst aqueous solution and solution A obtained in step (1) until a white suspension is obtained, and then stirring is continued for 60 min; the catalyst aqueous solution is ammonia water; and the mass ratio of the catalyst aqueous solution to the silicon source compound is 20:1;

[0078] (3) filtering the white suspension obtained in step (2) to obtain white blocks, drying at 200° C. for 16 h to remove physically adsorbed water to obtain powder A;

[0079] (4) The powder A obtained in step (3) is calcined in a push plate furnace, and the temperature in the tunnel furnace rises to 900° C. in 160 min, and the powder A stays therein for 240 min. During this process, the organic matter in the powder A is removed, and the powder A is densified to obtain the chip-grade silica filler.

[0080] Example 5

[0081] This embodiment provides a method for preparing a chip-level silica filler, the preparation method comprising the following steps:

[0082] (1) mixing a co-solvent solution and a silicon source compound in a mass ratio of 50:1 to obtain a solution A; the co-solvent solution is composed of a co-solvent and deionized water in a mass ratio of 1:1; the co-solvent is cyclohexane; and the silicon source compound is (3-mercaptopropyl)trimethoxysilane;

[0083] (2) stirring and mixing a 20 wt % catalyst aqueous solution and the solution A obtained in step (1) at 250 rpm at 30° C. until a white suspension is obtained, and then stirring is continued for 100 min; the catalyst aqueous solution is ammonia water; and the mass ratio of the catalyst aqueous solution to the silicon source compound is 1:1;

[0084] (3) filtering the white suspension obtained in step (2) to obtain white blocks, drying at 120° C. for 20 h to remove physically adsorbed water to obtain powder A;

[0085] (4) The powder A obtained in step (3) is calcined in a box furnace, and the temperature in the tunnel furnace rises to 1200° C. in 200 min, and the powder A stays therein for 180 min. During this process, the organic matter in the powder A is removed, and the powder A is densified to obtain the chip-grade silica filler.

[0086] Example 6

[0087] This embodiment provides a method for preparing a chip-level silica filler, which is the same as that of Embodiment 1 except that the mass of the co-solvent and the like is replaced by isopropanol.

[0088] Example 7

[0089] This embodiment provides a method for preparing a chip-level silica filler, which is the same as that of Embodiment 1 except that the mass of the co-solvent and the like is replaced by methanol.

[0090] Example 8

[0091] This embodiment provides a method for preparing a chip-level silica filler, which is the same as that of Embodiment 1 except that the mass of the co-solvent and the like is replaced by ethanol.

[0092] Example 9

[0093] This embodiment provides a method for preparing a chip-level silica filler, which is the same as that of Embodiment 1 except that the mass of the silicon source compound is replaced by vinyltrimethoxysilane.

[0094] Example 10

[0095] This embodiment provides a method for preparing a chip-level silica filler, which is the same as that of Embodiment 1 except that the mass of the silicon source compound is replaced by tetramethoxysilane.

[0096] Embodiment 11

[0097] This embodiment provides a method for preparing a chip-level silica filler, which is the same as that of Embodiment 1 except that the mass of the silicon source compound is replaced by tetrapropoxysilane.

[0098] Example 12

[0099] This embodiment provides a method for preparing a chip-level silica filler, which is the same as that of Embodiment 1 except that the mass of the silicon source compound is replaced by sodium silicate.

[0100] Comparative Example 1

[0101] This comparative example provides a method for preparing a silica filler, which is the same as Example 1 except that the co-solvent solution is not used, but the silicon source compound is directly mixed with the catalyst aqueous solution.

[0102] Performance Testing

[0103] The purity, sphericity and particle size distribution of the silica fillers obtained in the above examples and comparative examples were tested. The purity was tested according to SJ / T 3228.4-2016, the sphericity was tested according to GB / T 32661-2016, and the particle size distribution was tested according to GB / T 19077-2016.

[0104] The results are shown in Table 1.

[0105] Table 1

[0106] Purity (wt%) Sphericity(%) D50(μm) D100(μm) D100 / D50 Example 1 99.98 99.62 3.05 7.42 2.43 Example 2 99.96 99.56 1.02 2.77 2.72 Example 3 99.95 98.51 0.36 1.03 2.86 Example 4 99.91 98.43 0.53 1.74 3.28 Example 5 99.9 98.29 0.81 2.62 3.23 Example 6 99.94 99.52 1.42 3.66 2.58 Example 7 99.93 99.26 1.76 6.16 3.50 Example 8 99.95 99.37 1.65 5.37 3.25 Example 9 99.92 98.93 2.35 6.78 2.89 Example 10 99.95 99.31 2.73 6.98 2.56 Embodiment 11 99.94 99.42 1.98 5.39 2.72 Example 12 99.93 98.74 2.29 6.12 2.67 Comparative Example 1 99.35 97.3 3.61 9.52 2.64

[0107] In summary, the silicon dioxide filler for chip-level bottom filling glue prepared by the preparation method of the present invention has a purity of ≥99.9%, a sphericity of 98≥%, and a low impurity ion content; and a particle size distribution D50 of 0.3-8μm and D100 of 1-20μm, which meets the requirements of flip chip packaging. In addition, by regulating the ratio of the co-solvent, the catalyst and the silicon source compound, the average particle size and the cut-off point of the prepared silicon dioxide can be controlled, without the need for subsequent classification, screening and grading process operations.

[0108] The above description is only a specific implementation mode 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 thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a silicon dioxide filler for chip-level bottom filling glue, characterized in that: The preparation method consists of the following steps: (1) mixing a co-solvent solution and a silicon source compound in a mass ratio of (15-50):1 to obtain a solution A; the co-solvent solution comprises a co-solvent and water in a mass ratio of (10-50):(10-100); (2) mixing a catalyst aqueous solution with the solution A obtained in step (1) to obtain a suspension; the mass ratio of the catalyst aqueous solution to the silicon source compound is (1-20):1; the concentration of the catalyst aqueous solution is 0.1-20wt%; (3) The suspension obtained in the solid-liquid separation step (2) is used to wash the obtained solid, and after drying, a powder A is obtained; (4) calcining the powder A obtained in step (3) to obtain the chip-grade silica filler; the calcination temperature is 1000-1100° C.; The obtained chip-grade silica filler has a purity of ≥99.9%, a sphericity of ≥98%, a particle size distribution D50 of 1.02-8 μm, and a D100 of 2.77-20 μm.

2. The preparation method according to claim 1, characterized in that: The co-solvent in step (1) includes any one of methanol, ethanol, isopropanol or cyclohexane, or a combination of at least two of them.

3. The preparation method according to claim 1, characterized in that: The silicon source compound in step (1) includes any one of organic silicon and silicate or a combination of at least two of them.

4. The preparation method according to claim 3, characterized in that: The organic silicon includes any one of vinyl trimethoxy silane, vinyl triethoxy silane, (3-mercaptopropyl) trimethoxy silane, allyl trimethoxy silane, 3-glycidyloxypropyl trimethoxy silane or dodecyl trimethoxy silane, or a combination of at least two thereof.

5. The preparation method according to claim 3, characterized in that: The organic silicon includes siloxane, and the siloxane includes any one of tetramethoxysilane, tetraethoxysilane, or tetrapropoxysilane, or a combination of at least two thereof.

6. The preparation method according to claim 3, characterized in that: The silicate includes sodium silicate.

7. The preparation method according to claim 1, characterized in that: The mixing temperature in step (2) is 30-60°C.

8. The preparation method according to claim 1, characterized in that: The catalyst aqueous solution in step (2) includes any one of an inorganic acid aqueous solution, an inorganic base aqueous solution or an organic acid aqueous solution, or a combination of at least two of them.

9. The preparation method according to claim 1, characterized in that: The mixing in step (2) includes stirring and mixing until a suspension is obtained, and then continuing to stir for 10-300 minutes.

10. The preparation method according to claim 9, characterized in that: The rotation speed of the stirring and mixing is 150-250 rpm.

11. The preparation method according to claim 1, characterized in that: The suspension obtained in step (2) is a white suspension.

12. The preparation method according to claim 1, characterized in that: The solid-liquid separation method in step (3) includes any one of filter pressing, centrifugation or sedimentation, or a combination of at least two of them.

13. The preparation method according to claim 1, characterized in that: The drying temperature in step (3) is 30-220°C.

14. The preparation method according to claim 1, characterized in that: The drying time in step (3) is 1-24 hours.

15. The preparation method according to claim 1, characterized in that: The calcination time in step (4) is 10-300 min.

16. The preparation method according to claim 1, characterized in that: The calcination device used in step (4) includes any one of a tube furnace, a box furnace, a tunnel furnace, a push plate furnace or a track furnace, or a combination of at least two of them.

17. The preparation method according to claim 1, characterized in that: The preparation method consists of the following steps: (1) mixing a co-solvent solution and a silicon source compound in a mass ratio of (1-50):1 to obtain a solution A; the co-solvent solution comprises a co-solvent and water in a mass ratio of (10-50):(10-100); (2) stirring the catalyst aqueous solution and the solution A obtained in step (1) at 30-60° C. at a speed of 150-250 rpm until a white suspension is obtained, and then continuing to stir for 10-300 min; the mass ratio of the catalyst aqueous solution to the silicon source compound is (1-20):1; (3) The suspension obtained in the solid-liquid separation step (2) is washed with the obtained solid, and dried at 30-220° C. for 1-24 h to obtain powder A; (4) Calcining the powder A obtained in step (3) at 1000-1100° C. to obtain the chip-grade silica filler, with the calcination time being 10-300 min.

18. A silicon dioxide filler for chip-level bottom filling glue, characterized in that: The chip-grade silica filler is obtained by the preparation method according to any one of claims 1 to 8.

Images