Manufacturing method for ultra-low cut point spherical silicon fine powder for HDI

Abstract

The present invention discloses a method for producing ultra-low cut point spherical silicon micropowder for HDI, which includes the following steps: (1) selecting flame-processed spherical silicon micropowder with D50=1-15 μm and D100=10-50 μm as raw material, (2) mixing water and the flame-processed spherical silicon micropowder in a predetermined ratio, followed by high-speed stirring and ultrasonic treatment to obtain slurry A, (3) allowing slurry A to settle and siphoning off the upper layer of slurry to obtain product B, (4) centrifuging product B and dehydrating the upper layer paste after centrifugation to obtain product C, and (5) depolymerizing product C to obtain ultra-low cut point spherical silicon micropowder for HDI with D100≦6 μm. The method of the present application is simple and easy to implement, using micron-sized spherical silicon obtained by a conventional flame process as raw material, and sequentially carrying out the steps of slurry preparation, sedimentation, centrifugation, and depolymerization to obtain spherical silicon fine powder with D100≦6μm, high purity, and high sphericity, which meets the maximum size requirements for fillers in high-end HDI application fields.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to a Chinese patent application filed with the China Patent Office on December 21, 2023, bearing application number CN202311767719.3 and entitled "Method for producing ultra-low cut point spherical silicon micropowder for HDI," the entire contents of which are incorporated herein by reference. [Technical Field]

[0002] This application belongs to the technical field of inorganic fillers and relates to a method for producing ultra-low cut point spherical silicon fine powder for HDI. [Background technology]

[0003] With the advent of the 5G era, high-end electronic devices are constantly evolving toward higher frequencies, higher speeds, higher integration, and thinner designs, and the copper clad laminate industry, an extremely important raw material for electronic devices, is also responding by implementing space-saving designs such as finer hole diameters, higher wiring density, and back-drilled wiring. These increasingly miniaturized designs not only require ultra-thin substrate materials, PP, copper foil, etc., but also impose stricter restrictions on the maximum particle size of the upstream filler in HDI boards, with filler D100≦6μm required for advanced HDI products.

[0004] Silica, the most widely used filler in copper-clad laminates, has attracted widespread attention due to its excellent chemical stability, moderate hardness, ease of processing, and excellent electrical performance. Traditional rectangular silicon powders have high viscosity during use, limiting the filling ratio and preventing them from meeting the filler performance requirements of the HDI industry. It is difficult to completely eliminate large particles in common spherical silicon powder, making D100 unable to meet the filler size limitations of the HDI industry. Other types of spherical silicon powder, such as spherical silicon produced by liquid-phase synthesis and spherical silicon produced by combustion synthesis, remain expensive and unable to meet the cost management needs of the HDI industry. Therefore, to meet the continuous iteration of electronic products and promote the continuous upgrade of communication technology, it is necessary to develop products with D100≦6μm based on common flame-processed spherical silicon. At the same time, to meet the requirements of electronic-grade materials, these fillers must also possess high purity characteristics.

[0005] Currently, there are two commonly used methods for removing large particles from powders: ball milling and classifying / shredding. Patent Document 1 uses a ball mill to grind raw materials such as quartz sand and glass chips, while simultaneously adding a dispersing agent to reduce the agglomeration effect. While this method produces products with a narrow particle size distribution, low cut point, and low specific surface area (SSA), it destroys the spherical particle shape and eliminates the flowability advantages of spherical powders. Patent Document 2 uses a precision classification process to classify powders with a D100 in the range of 5 to 55 μm, and the products obtained using this method are inexpensive. However, even when the classifier rotation speed is increased to 4000 r / min, the D100 can only be reduced to 8.1 μm. Reducing the D100 to 6 μm or less requires very high hardware requirements for the classifier, including rotational speed, strength, and wear resistance, and the associated equipment is difficult to purchase.

[0006] Therefore, developing a method for producing ultra-low cut point spherical silicon micropowder that has low equipment requirements and is easy to operate, and producing ultra-low cut point, low viscosity, high purity spherical silicon micropowder products, is of great significance in responding to the progress of miniaturization and thinning of communication devices in the 5G era. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Chinese Patent Application Publication No. 113462196 [Patent Document 2] Chinese Patent No. 106335905 Summary of the Invention [Problem to be solved by the invention]

[0008] The present application aims to provide a method for producing spherical silicon fine powder with an ultra-low cut point for HDI. [Means for solving the problem]

[0009] The technical solutions to achieve the objectives of this application are as follows: A method for producing ultra-low cut point spherical silicon fine powder for HDI, comprising the steps of: (1) A step of selecting a raw material: spherical silicon fine powder produced by a flame method having a D50 of 1 to 15 μm and a D100 of 10 to 50 μm is selected and used as the raw material. (2) A step of preparing a slurry, in which water and the raw materials from step (1) are mixed in a mass ratio of 0.5 to 5:1, and the mixture is stirred at high speed at 1500 to 3000 r / min while being subjected to ultrasonic treatment at 18000 to 20000 Hz to obtain slurry A. (3) A settling step, in which the slurry A is allowed to settle for 5 to 20 hours, and after settling, the upper layer of the slurry is sucked out to obtain a product B. (4) A centrifugal separation step, in which product B is centrifuged at a rotation speed of 3000 to 5000 r / min to perform solid-liquid separation, and the upper layer paste obtained by solid-liquid separation is dehydrated to obtain product C. (5) Depolymerization step: depolymerizing the product C to obtain ultra-low cut point spherical silicon fine powder for HDI with D100≦6 μm.

[0010] In step (1), the spherical silicon fine powder produced by the flame method refers to spherical silicon fine powder produced by the flame method, and further, the spherical silicon fine powder produced by the flame method has a D50 of 3 to 9 μm and a D100 of 10 to 30 μm.

[0011] Furthermore, in step (2), the mass ratio of the water to the spherical silicon fine powder obtained by the flame method is 0.8 to 2:1, the processing time of the high-speed stirring and ultrasonic treatment is 10 to 30 minutes, and the stirring device used for the high-speed stirring is an electric stirrer or a high-speed stirrer.

[0012] Furthermore, in step (3), the settling device used for the settling is a settling bucket or a settling vessel.

[0013] Furthermore, in step (4), the rotation speed of the centrifuge is 3750 to 4100 r / min, the dehydration method is drying in a high-temperature air dryer or natural drying, preferably drying in a high-temperature air dryer, the drying temperature in the high-temperature air dryer is 100 to 110°C, and the drying time is 4 to 20 hours.

[0014] Furthermore, in step (5), the depolymerization apparatus used for the depolymerization is one or more of a ball mill, a high-speed stirrer, and an airflow pulverizer, preferably an airflow pulverizer, which can maintain the original spherical shape while avoiding the inclusion of other impurities.

[0015] The ultra-low cut point spherical silicon fine powder for HDI is manufactured by the manufacturing method described in the above technical solution, and the ultra-low cut point spherical silicon fine powder for HDI has a D100≦6 μm. [Effects of the Invention]

[0016] Compared with existing technologies, the present application has the following advantages: (1) This application uses water as a solvent, which is inexpensive, has good compatibility with silicon micropowder, and is environmentally friendly. The ratio of water to spherical silicon micropowder is controlled to produce a slurry together with spherical silicon micropowder produced by a flame method, and ultrasonic treatment is then carried out simultaneously under high-speed stirring. The ultrasonic waves sufficiently dissolve the agglomeration of the fine powder present in the slurry through high-speed stirring, allowing the powder to be dispersed more uniformly in water, preventing particles of 6 μm or less from agglomerating into larger particles and being sieved out.

[0017] (2) In this application, spherical silicon micropowder is formed into a slurry by the flame method and then directly settled. Under the combined action of gravity, buoyancy, collision forces between single crystals, and intermolecular attractive and repulsive forces, larger single crystal particles fall before smaller particles. Within a certain time, all large particles (6 μm or larger) fall to the bottom of the container, forming a settled layer. The moisture content in this settled layer is extremely low. Due to the superhydrophilic properties of silicon micropowder, this settled layer has a certain strength and is not easily broken. The settling step allows for the removal and separation of large particles (6 μm or larger). Furthermore, as the large particles settle, a certain amount of small particles also fall into the settled layer, resulting in a corresponding decrease in the D50 of the product.

[0018] (3) This application uses micrometer-sized spherical silicon obtained by a general flame method as raw material, controls the D50 and D100 of the raw material, and mixes the spherical silicon powder with water to form a slurry, which is then subjected to sequential steps of sedimentation, centrifugation, and depolymerization to obtain spherical silicon powder with D100≦6μm, high purity, and high sphericity, which meets the maximum size requirements of fillers in high-end HDI application fields. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is an SEM image of the spherical silicon fine powder product produced in Example 2. [Figure 2] FIG. 1 is an SEM image of the raw material of Example 2. [Figure 3] FIG. 1 is an SEM image of a spherical silicon fine powder product produced in Comparative Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present application will be described in more detail below with reference to specific examples and drawings.

[0021] Example 1 Using spherical silicon powder obtained by the flame method (D50 = 5 μm, D100 = 15 μm) as the raw material and deionized water as the solvent, the deionized water and raw material were mixed in a mass ratio of 1:1 into a high-speed mixer and stirred at a rotation speed of 3000 r / min for 15 minutes. Ultrasonic waves were applied at a frequency of 18000 Hz while stirring, yielding slurry A1. Slurry A1 was then poured into a settling vessel and allowed to settle for 7 hours. After settling, the upper layer of the slurry was extracted using a suction device to yield product B1.

[0022] Product B1 was placed in a centrifuge and centrifuged at a rotation speed of 4000 r / min. After centrifugation, the upper layer was placed in a high-temperature blower dryer and dried at 100°C for 12 hours to obtain Product C1. Product C1 was depolymerized using an airflow mill to obtain Final Product D1. As shown in Table 1, by undergoing the manufacturing process of Example 1, a spherical silicon fine powder product with a D100 reduced to 5.5 μm was manufactured.

[0023] Example 2 This example is substantially the same as Example 1, except for the following points: The raw material was spherical silicon fine powder produced by a flame method with D50 = 3 μm and D100 = 10 μm, the mass ratio of deionized water to raw material was 2:1, and stirring was performed using an electric stirrer. The stirring time was 20 min, the stirrer rotation speed was 1500 r / min, the ultrasonic frequency was 20000 Hz, the sedimentation time was 5 h, the centrifuge rotation speed was 3750 r / min, the drying temperature was 110 ° C, and the drying time was 14 h, resulting in a final product D2. As shown in Table 1, by undergoing the manufacturing process of Example 2, a spherical silicon fine powder product with a D100 reduced to 5.2 μm was produced.

[0024] FIG. 1 is an SEM image of the spherical silicon micropowder product produced in Example 2, and FIG. 2 is an SEM image of the raw material of Example 2. As can be seen from the figures, there is no obvious change in the sphericity of the product after going through the production process of Example 2, and it still maintains a high level.

[0025] Example 3 This example is substantially the same as Example 1, except for the following points: The raw material was a spherical silicon powder produced by a flame method with a D50 of 9 μm and a D100 of 30 μm. The mass ratio of deionized water to the raw material was 0.8:1. The stirring was carried out using an electric stirrer, the stirring time was 30 min, the stirrer rotation speed was 2000 r / min, the ultrasonic frequency was 20000 Hz, the settling time was 20 h, the centrifuge rotation speed was 4100 r / min, the drying temperature was 105 ° C, and the drying time was 20 h, resulting in a final product D3. As shown in Table 1, by undergoing the manufacturing process of Example 3, a spherical silicon powder product with a D100 of 5.9 μm was produced.

[0026] Comparative Example 1 This comparative example is substantially the same as Example 1, except for the following points: The mass ratio of deionized water to raw materials is adjusted from 1:1 to 0.3:1.

[0027] Comparative Example 2 This comparative example is essentially the same as Example 1, except for the following: The settling time is adjusted from the original 5 h to 3 h.

[0028] Comparative Example 3 This comparative example uses the same raw materials as in Example 1, but the process path is adjusted from slurry preparation, sedimentation, centrifugation, depolymerization, to polishing, slurry preparation, centrifugation, and depolymerization. In other words, the sedimentation step is omitted, and a polishing step is added before slurry preparation. The polishing equipment used is a ball mill, the polishing time is 6 hours, and the subsequent parameters for slurry preparation, centrifugation, and depolymerization are the same as in Example 1.

[0029] Comparative Example 4 In this comparative example, the same raw materials as in Example 1 are used, but the process path is adjusted from slurry preparation, sedimentation, centrifugation, and depolymerization to classification, slurry preparation, centrifugation, and depolymerization. In other words, the sedimentation step is omitted, and a classification step is added before slurry preparation. The classification device used is a general classifier, and the rotation speed of the classifier is 3000 to 4000 r / min. The parameters for the subsequent slurry preparation, centrifugation, and depolymerization are the same as in Example 1.

[0030] Comparative Example 5 Comparative Example 5 is a spherical silicon powder product obtained by the flame method and purchased from the market. The application field of this product is the medium to high-end field of the HDI industry, and this product is currently well-known in the market.

[0031] [Table 1]

[0032] [Table 2]

[0033] As can be seen from Table 1, the spherical silicon micropowder products produced through the manufacturing processes of Examples 1 to 3 had D100≦6 μm and maintained their original sphericity, indicating that the spherical silicon micropowder products produced by the methods of the present application can meet the low cut point and high sphericity requirements of the HDI industry. As shown in Figure 3, comparing the examples with Comparative Example 3, it can be seen that although the traditional silica particle control method, the polishing method, can reduce D100, the original spherical powder cannot maintain its spherical shape due to the frequent collisions between particles and between particles and the polishing medium during polishing, resulting in irregular shapes and a failure to reduce D100 below 6 μm. Comparing the examples with Comparative Example 4, it can be seen that the classification method, even when the classification efficiency is increased to the limit of conventional machines, is unable to remove all large particles present in the powder. Neither method achieves the objective of obtaining spherical silicon micropowder with D100≦6 μm.

[0034] As can be seen from Table 2, the D100 of the product produced in Example 2 is smaller than that of the spherical silicon powder for HDI (Comparative Example 5) which is well known in the market, which indicates that the spherical silicon powder product produced by the present application can be applied to higher-end fields in the HDI industry. In addition, the number of non-metallic foreign matter in the product produced in Example 2 is smaller than that of Comparative Example 5, which indicates that the spherical silicon powder product produced by the present application is characterized by high purity.

[0035] As described above, the ultra-low cut point spherical silicon fine powder for HDI manufactured by this application has the characteristics of low cut point, high sphericity, and high purity, and meets the requirements for fillers for the development of smaller and thinner communication devices in the 5G era.

[0036] The above embodiments provide a detailed description of the present invention, but they are only some of the embodiments, not all of the embodiments of the present invention. Based on these embodiments, one can obtain other embodiments without inventive step, and all of these embodiments also fall within the protection scope of the present invention.

Claims

1. A method for producing ultra-low cut point spherical silicon fine powder for HDI, comprising: A step (1) of selecting a raw material, in which spherical silicon fine powder having a D50 of 1 to 15 μm and a D100 of 10 to 50 μm obtained by a flame method is selected and used as the raw material; A step of preparing a slurry, comprising mixing water and the raw material of step (1) in a mass ratio of 0.5 to 5:1, stirring at high speed at 1500 to 3000 r / min, and simultaneously performing ultrasonic treatment at 18000 to 20000 Hz to obtain a slurry A (step (2)); (3) a settling step, in which the slurry A is allowed to settle for 5 to 20 hours, and after settling, the upper layer of the slurry is extracted to obtain a product B; A step (4) of centrifuging the product B at a rotation speed of 3000 to 5000 r / min to perform solid-liquid separation, and dehydrating the upper layer paste obtained by solid-liquid separation to obtain product C; and (5) a depolymerization step, in which the product C is depolymerized to obtain ultra-low cut point spherical silicon fine powder for HDI with D100≦6 μm.

2. 2. The method according to claim 1, wherein in step (1), the spherical silicon fine powder obtained by the flame method has a D50 of 3 to 9 μm and a D100 of 10 to 30 μm.

3. 2. The method of claim 1, wherein in step (2), the mass ratio of the water to the spherical silicon powder obtained by the flame method is 0.8 to 2:1, and the processing time of the high-speed stirring and ultrasonic treatment is 10 to 30 minutes.

4. 2. The method according to claim 1, wherein the stirring device used for the high-speed stirring in step (2) is an electric stirrer or a high-speed stirrer.

5. 2. The method according to claim 1, wherein the settling device used for the settling in step (3) is a settling bucket or a settling cauldron.

6. 2. The method of claim 1, wherein in step (4), the rotation speed of the centrifuge is 3750 to 4100 r / min.

7. 2. The method of claim 1, wherein in step (4), the dehydration method is drying in a high-temperature blower dryer or natural drying.

8. 8. The method of claim 7, wherein in step (4), the dehydration method is drying in a high-temperature air dryer, the drying temperature in the high-temperature air dryer is 100 to 110°C, and the drying time is 4 to 20 hours.

9. 2. The method according to claim 1, wherein the depolymerization apparatus used in step (5) is one or more of a ball mill, a high-speed mixer, and an airflow pulverizer.

10. 10. An ultra-low cut point spherical silicon fine powder for HDI manufactured by the manufacturing method according to any one of claims 1 to 9, wherein the ultra-low cut point spherical silicon fine powder for HDI has a D100≦6 μm.

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