Spherical crystalline silicon oxide powder as well as preparation method and application thereof

Abstract

The invention relates to the technical field of semiconductor substrates and packaging fillers, and discloses spherical crystalline silicon oxide powder as well as a preparation method and application thereof. In the prior art, a substrate membrane material prepared by taking spherical crystal silicon oxide powder as a filler is easy to cause the problem of interface stripping. According to the invention, at least one connecting recess is arranged on the surface of at least 50% of particles in the spherical crystalline silicon oxide powder, and the maximum width of the connecting recess is less than 180nm under the observation of a non-metal spraying field emission electron microscope. Furthermore, through the arrangement of the connecting recesses on the surfaces of the particles in the powder, the connecting strength between the powder and the connecting material is enhanced, so that the peel strength between a packaging film material prepared by taking the spherical crystal silicon oxide powder as a filler and a copper foil layer is increased, and the problem of interface peeling caused by cristobalite crystals is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor substrates and packaging fillers, and in particular to a spherical crystalline silicon oxide powder and a preparation method and application thereof. Background Art

[0002] Since silicon dioxide has a low coefficient of thermal expansion, when mixed with resin, silicon dioxide has the effect of reducing the coefficient of thermal expansion of the mixture. Therefore, in packaging materials, silicon dioxide is usually used as a filler to reduce the coefficient of thermal expansion of the packaging material. As the signal frequency of electronic equipment increases, the heat generated also increases. The design requirements of the packaging materials used in electronic equipment are to effectively dissipate the heat generated by the operation of the equipment. However, the thermal conductivity of amorphous silicon dioxide is low. When amorphous silicon dioxide is used as a filler in packaging materials, the heat dissipation performance of the packaging materials cannot meet the heat dissipation requirements of current electronic equipment.

[0003] Compared with amorphous silica, crystalline silica has a regular and dense structure, so it has a higher thermal conductivity. Silica has crystal structures such as cristobalite, α-quartz, and tridymite. Among them, quartz crystal has a denser crystal structure than other crystals and has a higher thermal conductivity. Therefore, using quartz crystal as a filler for packaging materials can effectively improve the heat dissipation effect of packaging materials. Although cristobalite crystals also have a relatively dense regular crystal structure, cristobalite crystals will undergo thermal expansion from the α-cristobalite phase to the β-cristobalite phase between 200 and 300°C, and the process temperature of the reflow soldering section in the semiconductor production process is between 200 and 300°C. Therefore, if there is a certain amount of cristobalite crystals in the packaging material, it will cause the interface between the packaging film material and the copper foil coating to peel off after the reflow soldering section. Therefore, cristobalite crystals are not suitable for fillers of packaging materials.

[0004] Compared with angular or irregular shaped silica powder, spherical silica powder has a higher filling rate in the filling of packaging materials. Therefore, using spherical quartz crystal powder as a filler for packaging materials can make the packaging materials have a lower thermal expansion coefficient and higher thermal conductivity than other shapes of amorphous silica powder or other crystalline silica powder on the market.

[0005] For the preparation of quartz crystals, the prior art provides a process for preparing high-purity quartz, such as that disclosed in the Chinese patent application number 2014101619964, which uses high-silica as raw material, and obtains high-purity quartz through the processes of ore dressing → calcination → water quenching → grinding → magnetic separation → electrostatic separation → pickling → deionized water washing → drying. The raw material of this patent is irregular-shaped high-silica ore, and then the high-silica mineral is calcined to crystallize into quartz crystals. Therefore, the method of this patent has the following disadvantages: first, there is a problem of low quartz crystallinity; second, there is a problem of irregular quartz crystal shape, the quartz crystal has low sphericity, and the shape of the product is difficult to control; third, the particle size of the quartz crystal powder is large, and the particle size of the product is difficult to control.

[0006] Regarding the preparation of spherical quartz crystals, the prior art provides a method for obtaining crystalline silica particles, such as Japanese patent application No. 2008-162849, which uses amorphous silica as a raw material, surface-treats it with an organic metal compound selected from aluminum, magnesium and titanium, and then heat-treats it at 1000~1600°C to crystallize it. However, the method of this patent has the following problems: First, at high temperatures, the silicon dioxide particles that have been treated with metal surfaces tend to agglomerate during calcination, and it is necessary to crush tightly bound particle blocks to obtain particles, which will result in large differences in particle size and a large number of large-size particles; Second, due to the crushing, there will be a large number of broken (irregular-shaped) particles; Third, a large amount of metal ions is required to promote the crystallization of silicon dioxide particles into quartz crystals, so the metal element content in the quartz crystals is large. At a heat treatment temperature of 1000~1600℃, a large amount of metal ions will cause the quartz crystals to transform into cristobalite crystals. Therefore, the particles obtained by this method have too high a cristobalite crystal content, and the cristobalite crystal phase change will cause volume expansion. Summary of the invention

[0007] In order to solve the problems of low sphericity of the above-mentioned quartz crystal powder and interface peeling with resin, the present invention provides a spherical crystalline silicon oxide powder and a preparation method and application thereof.

[0008] The specific technical scheme of the present invention is: In the first aspect, the present invention provides a spherical crystalline silica powder. Based on the number of particles, at least 50% of the particles in the silica powder have at least one connection depression on their surfaces for enhancing the connection strength between the particles and the connecting material; under observation by a non-gold sprayed field emission electron microscope, the maximum width of the connection depression is less than 180 nm.

[0009] In order to improve the crystallinity and sphericity of α-quartz crystals, the spherical crystalline silicon oxide powder provided in the prior art needs to add a large amount of metal ions, which will cause the powder to contain a high content of cristobalite crystals. The cristobalite crystal phase change undergoes thermal expansion and thus causes interface peeling problems.

[0010] The present invention provides at least one connection depression on the surface of at least 50% of the particles in the spherical crystalline silicon oxide powder, and under observation of a field emission electron microscope without gold spraying, the maximum width of the connection depression is less than 180nm. By providing the connection depression on the surface of the particles in the powder, the connection strength between the powder and the connection material is enhanced, and the peeling strength between the packaging film material prepared by using the spherical crystalline silicon oxide powder as a filler and the copper foil layer can be increased, thereby solving the interface peeling problem caused by the presence of quartz crystals.

[0011] The connection depressions enhance the connection strength with the connection material through mechanical anchoring effect and specific surface area increase effect. The mechanical anchoring effect refers to enhancing the interface bonding through interlocking in the physical structure. The connection depressions provided on the surface of the spherical crystalline silicon oxide powder particles provided by the present invention allow resin or copper liquid to penetrate, and form mechanical interlocking after curing, thereby increasing the bonding strength. The specific surface area increase effect is achieved by increasing the specific surface area of ​​the powder particles and improving the adsorption performance through the setting of the connection depressions, thereby enhancing the connection strength between the powder particles and the connection material.

[0012] As a preferred embodiment of the spherical crystalline silicon oxide powder, the mass proportion of α-quartz crystals in the silicon oxide powder is greater than 80%.

[0013] α-quartz crystal has high thermal conductivity. Using α-quartz crystal as a filler for packaging materials can effectively improve the heat dissipation effect of packaging materials. The silicon oxide powder provided by the present invention has α-quartz crystal accounting for more than 80% by mass and has high thermal conductivity, so that the heat dissipation performance of the packaging material meets the heat dissipation requirements of current electronic equipment.

[0014] The spherical crystalline silicon oxide powder is preferably sieved through a 20 μm sieve, and the silicon oxide powder obtained by sieving the sieve has an average sphericity of 0.9 or more.

[0015] Compared with angular or irregular shaped silica powder, spherical silica powder has a higher filling rate in the filling of packaging materials. The silica powder provided by the present invention is sieved through a 20 μm sieve, and the average sphericity of the silica powder obtained from the sieve is above 0.9, which has a better filling rate and a lower thermal expansion rate.

[0016] As a preferred embodiment of the spherical crystalline silicon oxide powder, the free lithium content in the silicon oxide powder is below 30 ppm.

[0017] More preferably, the content of free lithium in the silicon oxide powder is below 15 ppm.

[0018] As a preferred embodiment of the spherical crystalline silicon oxide powder, the mass proportion of cristobalite crystals in the silicon oxide powder is not higher than 5%.

[0019] As the above-mentioned spherical crystalline silicon oxide powder, preferably, the average particle size of the silicon oxide powder is 0.3-10 μm.

[0020] As a preferred embodiment of the spherical crystalline silicon oxide powder, the 200° C. Karl Fischer moisture content of the spherical crystalline silicon oxide powder after being left for 24 hours at 25° C. and 50% RH is not higher than 400 ppm.

[0021] In a second aspect, the present invention provides a substrate film material comprising a resin matrix and spherical crystalline silicon oxide powder dispersed therein; the connecting depressions on the surface of the powder particles enhance the interface bonding strength between the powder and the resin matrix through a mechanical anchoring effect and a specific surface area increase effect, and enable the peel strength between the substrate film material and a copper foil coated on its surface to reach above 6.0 N / cm.

[0022] As a preferred embodiment of the above-mentioned substrate film material, the added amount of the powder is 30% to 80% of the total mass of the substrate film material.

[0023] As a preferred substrate film material, the resin is selected from one or more of epoxy resin, cyanate resin, polyphenylene ether resin and hydrocarbon resin.

[0024] As a preferred embodiment of the above-mentioned substrate film material, the substrate film material or the copper foil is roughened to synergistically improve the peeling strength with the powder depression.

[0025] In a third aspect, the present invention provides a method for preparing spherical crystalline silicon oxide powder, comprising the following steps: Step S1: providing spherical polysiloxane particles; Step S2: Spherical polysiloxane particles are mixed with a lithium source, and then calcined to obtain a product.

[0026] As a preferred preparation method, the spherical polysiloxane includes T units, and the T units are R1SiO3 - , R1 is a hydrocarbon group having 1 to 18 carbon atoms or a hydrogen atom.

[0027] Further preferably, the polysiloxane also contains Q units, D units, and / or M units, wherein Q unit = SiO4-, D unit = R2R3SiO2-, M unit = R4R5R6SiO2-, and R2, R3, R4, R5, and R6 are respectively a hydrogen atom or an independently selectable hydrocarbon group having 1 to 18 carbon atoms.

[0028] As a preferred embodiment of the above preparation method, the lithium source is a lithium salt, for example, lithium carbonate or lithium acetate.

[0029] As a preferred embodiment of the above preparation method, the calcination temperature is 720-1100°C.

[0030] As a preferred embodiment of the above preparation method, the calcination time is 7 to 30 hours.

[0031] As a preferred embodiment of the above preparation method, the calcination is carried out under an air atmosphere.

[0032] As another preferred embodiment of the above preparation method, the preparation method comprises the following steps: Step S1: providing spherical polysiloxane particles; Step S2: mixing spherical polysiloxane particles and a lithium source, and then calcining to obtain a product; Step S3: washing the calcined product; Step S4: heat-treating the cleaned calcined product.

[0033] More preferably, the cleaning method is: adjusting the pH of water to neutral or acidic, and then adding the water to the calcined product to clean it, and the cleaning temperature is 20°C to 300°C.

[0034] More preferably, the heat treatment temperature is 60-1100°C.

[0035] In a third aspect, the present invention provides the use of the above-mentioned spherical crystalline silicon oxide powder in the preparation of semiconductor packaging materials or substrate materials.

[0036] Compared with the prior art, the present invention has the following technical effects: (1) In the spherical crystalline silicon oxide powder provided by the present invention, at least 50% of the particles have at least one connection depression on their surfaces for enhancing the connection strength between the particles and the connecting material. The connection depressions on the surfaces of the powder particles enhance the interfacial bonding strength between the powder and the copper foil coating through the mechanical anchoring effect and the specific surface area increase effect. The peel strength between the substrate film material prepared using the spherical crystalline silicon oxide powder as a filler and the copper foil coated on its surface reaches 6.0 N / cm or more, which has the advantage of a large interfacial peeling strength with the copper foil coating.

[0037] (2) The spherical crystalline silicon oxide powder provided by the present invention has the characteristics of high sphericity and high quartz crystallinity.

[0038] (3) The spherical crystalline silicon oxide powder provided by the present invention has a free lithium content of less than 30 ppm, and more preferably, a free lithium content of less than 15 ppm. The low free lithium content and total lithium content in the filler powder are beneficial to improving the reliability of semiconductor devices.

[0039] (4) The spherical crystalline silicon oxide powder provided by the present invention has a low moisture content, which is beneficial for reducing the dielectric loss of semiconductor devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a scanning electron microscope (SEM) photograph of the spherical crystalline silicon oxide powder prepared in Example 1 of the present invention; Figure 2 Another scanning electron microscope (SEM) photograph of the spherical crystalline silicon oxide powder prepared in Example 1 of the present invention; Figure 3 This is a scanning electron microscope (SEM) photograph of the spherical crystalline silicon oxide powder prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should belong to the scope of protection of the present invention.

[0042] The present invention provides a spherical crystalline silicon oxide powder. Counted by the number of particles, at least 50% of the particles in the silicon oxide powder are provided with at least one connection depression on their surfaces for enhancing the connection strength between the particles and a connecting material. Under observation with a field emission electron microscope without gold spraying, the maximum width of the connection depression is less than 180 nm.

[0043] In order to improve the crystallinity and sphericity of α-quartz crystals, the spherical crystalline silicon oxide powder provided in the prior art needs to add a large amount of metal ions, which will cause the powder to contain a high content of cristobalite crystals. The cristobalite crystal phase change undergoes thermal expansion and thus causes interface peeling problems.

[0044] The present invention provides at least one connection depression on the surface of at least 50% of the particles in the spherical crystalline silicon oxide powder, and under observation of a field emission electron microscope without gold spraying, the maximum width of the connection depression is less than 180nm. By providing the connection depression on the surface of the particles in the powder, the connection strength between the powder and the connection material is enhanced, and the peeling strength between the packaging film material prepared by using the spherical crystalline silicon oxide powder as a filler and the copper foil layer can be increased, thereby solving the interface peeling problem caused by the presence of quartz crystals.

[0045] The connection depressions enhance the connection strength with the connection material through mechanical anchoring effect and specific surface area increase effect. The mechanical anchoring effect refers to enhancing the interface bonding through interlocking in the physical structure. The connection depressions provided on the surface of the spherical crystalline silicon oxide powder particles provided by the present invention allow resin or copper liquid to penetrate, and form mechanical interlocking after curing, thereby increasing the bonding strength. The specific surface area increase effect is achieved by increasing the specific surface area of ​​the powder particles and improving the adsorption performance through the setting of the connection depressions, thereby enhancing the connection strength between the powder particles and the connection material.

[0046] The length of the connection depression cannot be greater than 180 nm, otherwise, the mechanical interlocking strength between the powder particles and the connection material caused by the connection depression is insufficient, the mechanical anchoring effect is small, and ultimately the connection strength between the powder particles and the resin and copper foil layer is poor.

[0047] In the technical solution of the present invention, the connection depression can be prepared directly on the surface of the powder particles while crystallizing to form crystalline silicon oxide powder particles. In the specific implementation of the present invention, spherical polysiloxane particles are used as raw materials to prepare a powder containing α-quartz crystals, and the connection depression can be prepared on the surface of the particles while the raw powder particles are crystallized into crystalline silicon oxide powder particles. When polysiloxane particles are calcined, two reactions will occur simultaneously. One is that siloxane is converted into silicon dioxide, and the other is that siloxane is directly converted into α-quartz crystals under the action of lithium elements. Since there is a volume difference between the material transformations of these two reactions, cracks are formed, namely the connection depressions.

[0048] In one embodiment, the depth and length of the connection depression can be controlled by the calcination process. When the polysiloxane particles containing lithium are directly placed in a high-temperature calcination furnace, the heating speed is fast and the maximum length of the connection depression is large.

[0049] Generally, since cracks in particles will increase the absorption of water by particles, the silica balls in the prior art are based on the consideration of reducing dielectric loss, so "cracks" are often not desired. In the present application, due to the adjustment of the process for preparing spherical crystalline silica powder of the present invention, the crystallization and surface connection depressions are innovatively integrated in the powder particles, and the connection depressions on the surface of the powder particles are effectively utilized, so that the connection depressions are enhanced through mechanical anchoring effect and specific surface area increase effect. The present invention goes beyond the teaching of the prior art on the surface cracks of silica powder particles, and provides a new technical solution for silica powder particle products in the field, overcoming the technical prejudice of the field on the surface cracks of silica powder particles. At the same time, the crystallization inside the powder particles of the present invention can reduce the content of internal hydroxyl groups, which also helps to reduce dielectric loss.

[0050] Specifically, in the silicon oxide powder, at least 50% of the particles are provided with at least one connection depression on their surfaces. The specific embodiment is: randomly photographing the silicon oxide powder under a field emission electron microscope without gold spraying, and in the obtained view, among a number of particles with a complete spherical outline, at least 50% of the particles are provided with one connection depression, and the number is at least 10. For example, Figure 1 This is a photo of silicon oxide powder randomly taken under non-gold spraying field emission electron microscope observation in one embodiment. Figure 1 In the figure, the number of particles having a complete spherical contour is 29, and among the 29 particles, 3 particles (particles numbered 5, 6, and 17) do not have the connection depression on their surfaces, that is, based on the number of particles, 90% of the particles in the silicon oxide powder have at least one connection depression on their surfaces.

[0051] Specifically, the maximum width of the connecting depression can be measured under non-gold spraying field emission electron microscope observation, based on the particle having a complete spherical outline shown in the non-gold spraying field emission electron microscope observation image, along the longest path extending from the connecting depression on the particle surface, the opening at any point on the path is the width at that point, and the largest width at each point is the maximum width of the connecting depression on the particle surface. In the embodiment of the present invention, the maximum width of the connecting depression on the particle surface in the powder is the average value of the test samples, and the number of test samples is 10.

[0052] As a preferred embodiment of the spherical crystalline silicon oxide powder, the mass proportion of α-quartz crystals in the silicon oxide powder is greater than 80%.

[0053] α-quartz crystal has high thermal conductivity. Using α-quartz crystal as a filler for packaging materials can effectively improve the heat dissipation effect of packaging materials. The silicon oxide powder provided by the present invention has α-quartz crystal accounting for more than 80% by mass and has high thermal conductivity, so that the heat dissipation performance of the packaging material meets the heat dissipation requirements of current electronic equipment.

[0054] The spherical crystalline silicon oxide powder is preferably sieved through a 20 μm sieve, and the silicon oxide powder obtained by sieving the sieve has an average sphericity of 0.9 or more.

[0055] Compared with angular or irregular shaped silica powder, spherical silica powder has a higher filling rate in the filling of packaging materials. The silica powder provided by the present invention is sieved through a 20 μm sieve, and the average sphericity of the silica powder obtained from the sieve is above 0.9, which has a better filling rate and a lower thermal expansion rate.

[0056] As a preferred embodiment of the spherical crystalline silicon oxide powder, the free lithium content in the silicon oxide powder is below 30 ppm.

[0057] More preferably, the content of free lithium in the silicon oxide powder is below 15 ppm.

[0058] As a preferred embodiment of the spherical crystalline silicon oxide powder, the mass proportion of cristobalite crystals in the silicon oxide powder is not higher than 5%.

[0059] As the above-mentioned spherical crystalline silicon oxide powder, preferably, the average particle size of the silicon oxide powder is 0.3-10 μm.

[0060] As a preferred embodiment of the spherical crystalline silicon oxide powder, the 200° C. Karl Fischer moisture content of the spherical crystalline silicon oxide powder after being left for 24 hours at 25° C. and 50% RH is not higher than 400 ppm.

[0061] As a preferred embodiment of the spherical crystalline silicon oxide powder, the free lithium content in the silicon oxide powder is below 30 ppm.

[0062] The low content of free lithium can reduce the harm to the reliability of semiconductor devices.

[0063] As a preferred embodiment of the spherical crystalline silicon oxide powder, the mass proportion of cristobalite crystals in the silicon oxide powder is not higher than 5%.

[0064] Controlling the mass percentage of cristobalite crystals to less than 5% can effectively alleviate the problem of interface peeling between the film material and the copper foil layer. If the mass percentage of cristobalite crystals is too large, exceeding 5%, the phase transition of cristobalite crystals will lead to thermal expansion of the composite material with the resin, which will cause a sharp drop in the interface bonding force between the composite material and the copper foil layer. At this time, the bonding force improvement brought by setting at least one connection depression on the surface of the particles in the silicon oxide powder is not enough to resist the sharp drop in the interface bonding force.

[0065] In the present invention, since T-unit spherical polysiloxane particles are used as raw materials for preparing spherical crystalline silicon oxide powder, the raw materials can be transformed into α-quartz crystals under the condition of a small amount of metal ions. Since the metal ion content is small, the possibility of α-quartz crystals transforming into cristobalite crystals is greatly reduced. Therefore, the spherical crystalline silicon oxide powder provided by the present invention has a cristobalite crystal mass proportion of less than 5%.

[0066] As the spherical crystalline silicon oxide powder, preferably, the average particle size (D50) of the silicon oxide powder is 0.3 to 10 μm, and more preferably, the average particle size (D50) of the silicon oxide powder is 0.3 to 5 μm.

[0067] In the present invention, the particle size of the spherical crystalline silicon oxide powder can be controlled within a relatively small particle size range of 0.3 to 5 μm. When cristobalite crystallization is inevitable in the spherical crystalline silicon oxide powder and a small amount of cristobalite is contained, the spherical crystalline silicon oxide powder of 0.3 to 5 μm has a sphericity of more than 0.9, and because at least one connecting depression is provided on the surface of the particles in the powder, the composite material thereof with the resin can have excellent bonding strength when it is interfaced with other materials, and better resist the interface bonding strength reduction effect caused by the thermal expansion caused by the inevitable small amount of cristobalite.

[0068] As a preferred embodiment of the spherical crystalline silicon oxide powder, the 200° C. Karl Fischer moisture content of the spherical crystalline silicon oxide powder after being left for 24 hours at 25° C. and 50% RH is not higher than 400 ppm.

[0069] In the prior art, since a large amount of metal elements are contained in the powder when the raw material is crystallized into quartz by heat treatment, heat treatment and crystallization at a relatively high temperature will cause the silicon dioxide to crystallize into cristobalite. In the present invention, the lithium content in the spherical crystalline silicon oxide powder is relatively low, so the heat treatment can be carried out at a relatively high temperature, for example, it can be carried out at a temperature above 700°C. Heat treatment and crystallization at a high temperature above 700°C can reduce the hydroxyl content in the powder. The low hydroxyl content can reduce the affinity of the product of the spherical crystalline silicon oxide powder with moisture in the air, and has the property of not being easy to absorb water. The product finally has a low moisture content after being placed. Therefore, it is not difficult to see from the low moisture content of the spherical crystalline silica powder that even if a number of connecting depressions are set on the surface of the spherical crystalline silica powder particles, the connecting depressions will bring about an effect of increasing the surface area, but the amount of adsorbed water in the powder particles of the present invention is also small, and the water adsorption performance is low. This shows that the spherical crystalline silica powder should have a dense structure, so it is more difficult to adsorb moisture in the air. Using the powder as a filler for packaging materials has the excellent performance of low dielectric loss.

[0070] In summary, the spherical crystalline silicon oxide powder provided by the present invention, which has at least one connected depression on the surface of the particle, can improve the interface bonding force between the packaging material and the copper foil layer while maintaining a small amount of adsorbed water.

[0071] The present invention also provides a substrate film material, comprising a resin matrix and spherical crystalline silicon oxide powder dispersed therein; the connecting depressions on the surface of the powder particles enhance the interface bonding strength between the powder and the resin matrix through a mechanical anchoring effect and a specific surface area increase effect, and enable the peeling strength between the substrate film material and the copper foil coated on its surface to reach above 6.0 N / cm.

[0072] As a preferred embodiment of the above-mentioned substrate film material, the added amount of the powder is 30% to 80% of the total mass of the substrate film material.

[0073] As a preferred substrate film material, the resin is selected from one or more of epoxy resin, cyanate resin, polyphenylene ether resin and hydrocarbon resin.

[0074] As a preferred embodiment of the above-mentioned substrate film material, the substrate film material or the copper foil is roughened to synergistically improve the peeling strength with the powder depression.

[0075] The present invention also provides a method for preparing spherical crystalline silicon oxide powder, comprising the following steps: Step S1: providing spherical polysiloxane particles; Step S2: Spherical polysiloxane particles are mixed with a lithium source, and then calcined to obtain a product.

[0076] In the above preparation method, a powder containing α-quartz crystals is prepared using spherical polysiloxane particles as raw materials through steps S1 and S2, and the connection depression can be prepared on the surface of the particles while the raw powder particles are crystallized into crystalline silicon oxide powder particles. When the polysiloxane particles are calcined, two reactions will occur simultaneously. One is that siloxane is converted into silicon dioxide, and the other is that siloxane is directly converted into α-quartz crystals under the action of lithium elements. Since there is a volume difference between the material transformations of these two reactions, cracks are formed on the surface layer of the obtained particles, namely the connection depression. The product obtained after calcination is spherical silicon oxide, and the surface layer of the spherical silicon oxide has a loose structure, which is different from traditional spherical silicon oxide.

[0077] In the above preparation method, since spherical polysiloxane particles are used as raw materials for preparing spherical crystalline silicon oxide powder, the raw materials can be converted into α-quartz crystals under the condition of a small amount of metal ions. The amount of lithium source added is calculated as lithium oxide, so that the mass proportion of lithium oxide in the whole particles (polysiloxane particle mass + lithium oxide mass) is as low as 0.038% to 0.05%, and the mass proportion of α-quartz crystals in the product spherical crystalline silicon oxide powder can reach more than 80%, and the free lithium content in the product spherical crystalline silicon oxide powder can reach less than 15ppm.

[0078] In one implementation, the depth and length of the connection depression can be controlled by the calcination process. When the polysiloxane particles containing lithium are directly placed in a high-temperature calcination furnace, the heating speed is fast and the maximum length of the connection depression is large.

[0079] In one embodiment, the spherical polysiloxane comprises a T unit, wherein the T unit is R1SiO3 - , R1 is a hydrocarbon group having 1 to 18 carbon atoms or a hydrogen atom.

[0080] Preferably, the spherical polysiloxane further contains Q units, D units, and / or M units, wherein Q unit = SiO4-, D unit = R2R3SiO2-, M unit = R4R5R6SiO2-, and R2, R3, R4, R5, and R6 are respectively a hydrogen atom or an independently selectable hydrocarbon group having 1 to 18 carbon atoms.

[0081] The lithium source is a lithium salt, such as lithium carbonate and lithium acetate. The amount of lithium salt added is measured in terms of lithium element and in terms of lithium oxide, and the mass proportion of lithium oxide in the whole particles (mass of polysiloxane particles + mass of lithium oxide) is calculated.

[0082] The spherical polysiloxane particles and the lithium source can be mixed by wet mixing or dry mixing. The wet mixing is to add the lithium source to the slurry of the spherical polysiloxane particles, dry it appropriately to remove the liquid, and then calcine it. The dry mixing is to dry mix the spherical polysiloxane particles and the lithium source, and then calcine them.

[0083] In one implementation, the calcination temperature is 720-1100°C.

[0084] In one implementation, the calcination time is 7 to 30 hours.

[0085] In one implementation, the calcination is performed under an air atmosphere.

[0086] In one embodiment, the present invention also provides another method for preparing spherical crystalline silicon oxide powder, comprising the following steps: Step S1: providing spherical polysiloxane particles; Step S2: mixing spherical polysiloxane particles and a lithium source, and then calcining to obtain a product; Step S3: washing the calcined product; Step S4: heat-treating the cleaned calcined product.

[0087] In actual preparation, in order to ensure that the mass proportion of α-quartz crystals in the product powder is as large as possible, an excessive amount of lithium source is often added. For example, in terms of lithium oxide, the amount of lithium source added is increased to increase the mass proportion of lithium oxide in the overall particles (mass of polysiloxane particles + mass of lithium oxide) to 0.25% to 1%. In this case, in the preparation method of the present invention, steps S3 and S4 can be added to allow the free lithium content in the product spherical crystalline silicon oxide powder to reach less than 15 ppm.

[0088] When the amount of lithium source added is large, the mass proportion of α-quartz crystals in the product spherical crystalline silica powder can reach more than 80%, or even more than 95%. What is more advantageous is that under the premise of adding a large amount of lithium source and maintaining a high proportion of α-quartz crystals, the free lithium content in the product spherical crystalline silica powder can also reach below 15ppm.

[0089] More preferably, the cleaning method is: adjusting the pH of water to neutral or acidic, and then adding the water to the calcined product to clean it, and the cleaning temperature is 20°C to 300°C.

[0090] More preferably, the heat treatment temperature is 60-1100°C.

[0091] In the present invention, "the maximum width of the connection depression is less than 180nm" includes that the maximum width of the connection depression is 180nm. "The mass proportion of α-quartz crystals in the silicon oxide powder is more than 80%" includes that the mass proportion of α-quartz crystals in the silicon oxide powder is 80%. "The average sphericity of the silicon oxide powder is more than 0.9" includes that the average sphericity of the silicon oxide powder is 0.9. That is, in the present invention, the description involving "above" and "below" includes the number itself.

[0092] In the present invention, the average sphericity refers to the average sphericity measured by randomly selecting 40 particles under the sieve after the sample passes through a 20 μm sieve. The measurement method is to randomly record the particle image with SEM (the image magnification is 50,000 times) and calculate the area and perimeter of the particle to calculate the sphericity. The calculation formula of sphericity is: sphericity = 4π*area of ​​the particle / square of the perimeter of the particle. When the sphericity is closer to 1, the particle is closer to a perfect circle.

[0093] In the present invention, the crystal mass ratio is determined by the integrated area of ​​the non-crystallizing peak and the crystalline peak in the X-ray diffraction analysis. The calculation formula for the mass ratio of α-quartz crystals in silicon oxide powder is: α-quartz crystal mass ratio = α-quartz crystal peak area / (non-crystallizing peak integrated area + crystalline peak integrated area). The calculation formula for the mass ratio of cristobalite crystals in silicon oxide powder is: cristobalite crystal mass ratio = cristobalite crystal peak area / (non-crystallizing peak integrated area + crystalline peak integrated area).

[0094] In the present invention, the electron microscopic images are measured by a field emission scanning electron microscope Apreo 2c.

[0095] In the present invention, the free lithium content in the silicon oxide powder is the lithium ion content of the extracted water, and the measurement method is: add 60 ml of water to 6 grams of silicon oxide powder, heat to 150 ° C for hydrothermal reaction for 24 hours, dissolve the free Li ions in the silicon oxide powder in the water, and then test the Li element content in the water by inductively coupled plasma spectrometer (ICP). The lithium element in the silicon oxide powder includes free lithium and crystalline lithium. The crystalline lithium is fixed in the silicon oxide powder, so its reliability damage to the semiconductor device can be ignored, and the free lithium will cause greater damage to the reliability of the semiconductor device.

[0096] In the present invention, the total lithium content in the silicon oxide powder is measured by completely dissolving the silicon oxide powder with nitric acid to obtain a digestion solution, and using ICP to test the amount of Li in the digestion solution.

[0097] In the present invention, the water content of the silicon oxide powder is 200 degrees Celsius Karl Fischer water content, which is tested by a Karl Fischer titrator, the instrument is Mitsubishi Chemical's CA-310, and the determination method is the coulometric method.

[0098] In the present invention, the average particle size is measured by Beckman Coulter's laser particle size distribution analyzer LS-13320, and the solvent is pure water. In this patent, the average particle size refers to the volume average diameter of the particles.

[0099] In the present invention, the test method of the interfacial peel strength is as follows: 260 parts of silicon oxide powder are mixed with 40 parts by weight of epoxy resin (NC3000L, purchased from Nippon Kayaku), 10 parts by weight of aralkyl phenolic resin (ResiCare3600H, purchased from Hengfeng New Materials), 10 parts by weight of carbodiimide compound (V-03, purchased from Nisshinbo Chemical), 20 parts by weight of active ester resin (HPC-8000-65T, purchased from DIC, Japan), 1 part by weight of phenoxy resin (YX7553BH30, purchased from Mitsubishi Chemical), and 0.3 parts by weight of curing accelerator (DMAP, purchased from Guangrong Chemical) to prepare a packaging film on the surface of the core board, and copper is deposited on the surface of the packaging film to prepare a test sample; the test sample is placed at 250°C for 1 hour and then cooled, and the copper foil peel strength tester is used to test the copper bonding strength of the resin film using the IPC-TM-650 2.4.9 method.

[0100] In the embodiment of the present invention, the polysiloxane raw material used is polysiloxane prepared using methyltrimethoxysilane as the T unit.

[0101] Example 1 A powder is provided, and the preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0102] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured by lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass) in terms of lithium oxide. The mass of the polysiloxane particles is calculated by testing the mass of the polysiloxane slurry and the solid content of the polysiloxane slurry, and the calculation formula is: mass of polysiloxane particles = mass of polysiloxane slurry * solid content of polysiloxane slurry.

[0103] Step S3, put the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800°C at 60°C / min in an air atmosphere, and calcine for 24 hours to obtain spherical crystalline silicon oxide powder. The average particle size of the powder is 1.0 μm. The sample is observed by electron microscopy. Under the observation of non-gold spraying field emission electron microscopy, it is found that 90% of the particles in the powder have at least one connection depression on their surface. The electron microscopy image is as follows: Figure 1 Randomly observe the appearance of individual particles in the powder, electron microscope image Figure 2 shown.

[0104] Example 2 A powder is provided, and the preparation steps are different from those in Example 1, except that the calcination heating rate is 20°C / min. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0105] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0106] Step S3: Put the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at 20° C. / min in an air atmosphere, and calcine for 24 hours to obtain spherical crystalline silicon oxide powder.

[0107] Example 3 A powder is provided, and the preparation steps are different from those in Example 1, except that the calcination heating rate is 25°C / min. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0108] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0109] Step S3: Place the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at a rate of 25° C. / min in an air atmosphere, and calcine for 24 hours.

[0110] Example 4 A powder is provided, and the preparation steps are different from those in Example 1, except that the calcination heating rate is 30°C / min. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0111] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0112] Step S3: Place the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at a rate of 30° C. / min in an air atmosphere, and calcine for 24 hours.

[0113] Example 5 A powder is provided, and the preparation steps are different from those in Example 1, except that the calcination heating rate is 40°C / min. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0114] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0115] Step S3: Place the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at 40° C. / min in an air atmosphere, and calcine for 24 hours.

[0116] Example 6 A powder is provided, and the preparation steps are different from those in Example 1, except that the calcination heating rate is 50°C / min. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0117] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0118] Step S3: Put the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at a rate of 50° C. / min in an air atmosphere, and calcine for 24 hours.

[0119] Example 7 A powder is provided, and the preparation steps are different from those in Example 1, except that the calcination heating rate is 70°C / min. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0120] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0121] Step S3: Place the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at a rate of 70° C. / min in an air atmosphere, and calcine for 24 hours.

[0122] Example 8 A powder is provided, and the preparation steps are different from those in Example 1, except that: the calcination temperature in step S3 is: after the atmosphere furnace is preheated to 800°C, the particles are directly placed in the furnace. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0123] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0124] Step S3: preheat the atmosphere furnace to 800° C. under an air atmosphere, and then directly put the particles obtained in step S2 into the atmosphere furnace for calcination for 24 hours.

[0125] Example 9 A powder is provided, and the preparation steps are different from those in Example 1, except that: the calcination temperature in step S3 is: after the atmosphere furnace is preheated to 1100°C, the particles are directly placed in the furnace. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0126] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0127] Step S3: preheat the atmosphere furnace to 1100° C. under an air atmosphere, and then directly put the particles obtained in step S2 into the atmosphere furnace for calcination for 24 hours.

[0128] Example 10 A powder is provided, and the preparation steps are different from those in Example 1, except that the calcination temperature is 720°C, and a cleaning step and a heat treatment step after cleaning are added. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0129] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0130] Step S3: Place the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 720° C. at a rate of 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0131] Step S4, adding the particles obtained in step S3 into deionized water, stirring and washing for 3 times, and performing solid-liquid separation to obtain a washed filter cake sample.

[0132] Step S5, placing the filter cake in a 120° C. oven and drying it for 8 h, then placing it in an atmosphere furnace, heating it to 900° C. in an air atmosphere, and heat treating it for 24 h.

[0133] Embodiment 11 A powder is provided, and the preparation steps are different from those in Example 10, except that the calcination temperature is 900° C. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0134] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0135] Step S3: Place the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 900° C. at 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0136] Step S4, adding the particles obtained in step S3 into deionized water, stirring and washing for 3 times, and performing solid-liquid separation to obtain a washed filter cake.

[0137] Step S5, placing the filter cake in a 120° C. oven and drying it for 8 h, then placing it in an atmosphere furnace, heating it to 900° C. in an air atmosphere, and heat treating it for 24 h.

[0138] Example 12 A powder is provided, and the preparation steps are different from those in Example 10, except that the calcination temperature is 1100° C. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0139] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0140] Step S3: Place the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 1100° C. at a rate of 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0141] Step S4, adding the particles obtained in step S3 into deionized water, stirring and washing for 3 times, and performing solid-liquid separation to obtain a washed filter cake.

[0142] Step S5, placing the filter cake in a 120° C. oven and drying it for 8 h, then placing it in an atmosphere furnace, heating it to 900° C. in an air atmosphere, and heat treating it for 24 h.

[0143] Example 13 A powder is provided, and the preparation steps are different from those in Example 1 in that a cleaning step and a post-cleaning heat treatment step are added, wherein the temperature of the post-cleaning heat treatment step is 800° C. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0144] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0145] Step S3: Put the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0146] Step S4, adding the particles obtained in step S3 into deionized water, stirring and washing for 3 times, and performing solid-liquid separation to obtain a washed filter cake sample.

[0147] Step S5, placing the filter cake in a 120° C. oven and drying it for 8 h, then placing it in an atmosphere furnace, heating it to 800° C. in an air atmosphere, and heat treating it for 24 h.

[0148] Embodiment 14 A powder is provided, and the preparation steps are different from those in Example 1, except that the amount of lithium acetate added is measured in terms of lithium element, and in terms of lithium oxide, the lithium oxide accounts for 0.038wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass). The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0149] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.038wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0150] Step S3: Put the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0151] Embodiment 15 A powder is provided, and the preparation steps are different from those in Example 1, except that: the amount of lithium acetate added is measured in terms of lithium element, and in terms of lithium oxide, the lithium oxide accounts for 0.25wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass); a cleaning step and a post-cleaning heat treatment step are added. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0152] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.25wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0153] Step S3: Put the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0154] Step S4, adding the particles obtained in step S3 into deionized water, stirring and washing for 3 times, and performing solid-liquid separation to obtain a washed filter cake sample.

[0155] Step S5, placing the filter cake in a 120° C. oven and drying it for 8 h, then placing it in an atmosphere furnace, heating it to 800° C. in an air atmosphere, and heat treating it for 24 h.

[0156] Example 16 A powder is provided, and the preparation steps are different from those in Example 1, except that: the amount of lithium acetate added is measured in terms of lithium element, and in terms of lithium oxide, the lithium oxide accounts for 1wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass); a cleaning step and a post-cleaning heat treatment step are added. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 1.3 μm.

[0157] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 1wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0158] Step S3: Put the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0159] Step S4, adding the particles obtained in step S3 into deionized water, stirring and washing for 3 times, and performing solid-liquid separation to obtain a washed filter cake sample.

[0160] Step S5, placing the filter cake in a 120° C. oven and drying it for 8 h, then placing it in an atmosphere furnace, heating it to 800° C. in an air atmosphere, and heat treating it for 24 h.

[0161] Embodiment 17 A powder is provided, and the preparation steps are different from those in Example 1, except that the average particle size of the raw material polysiloxane particles is 0.3 μm. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking samples to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 0.3 μm.

[0162] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0163] Step S3: Put the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0164] Embodiment 18 A powder is provided, and the preparation steps are different from those in Example 1, except that the average particle size of the raw material polysiloxane particles is 5 μm. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking a sample to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 5 μm.

[0165] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0166] Step S3: Put the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0167] Embodiment 19 A powder is provided, and the preparation steps are different from those in Example 1, except that the average particle size of the raw material polysiloxane particles is 10 μm. The specific preparation steps are as follows: Step S1, at room temperature, taking polysiloxane slurry for standby use, and taking a sample to detect the average particle size (D50) of polysiloxane particles in the polysiloxane slurry, and the average particle size is measured to be 10 μm.

[0168] Step S2, adding lithium acetate solution to the polysiloxane slurry, stirring for half an hour to make the mixture uniform. The amount of lithium acetate added is measured as lithium element, and the lithium oxide accounts for 0.05wt% of the total particle mass (polysiloxane particle mass + lithium oxide mass).

[0169] Step S3: Put the particles obtained in step S2 into an atmosphere furnace, raise the temperature to 800° C. at 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0170] Comparative Example 1 A powder is provided, and the preparation steps are different from those in Example 1, except that the raw material is amorphous silicon dioxide spheres prepared by the deflagration method. The preparation is carried out according to the following steps: Step S1: prepare amorphous silica spheres by deflagration method, with an average particle size of 1.3 μm, add lithium carbonate to the amorphous silica spheres, and mix them evenly, wherein the lithium oxide accounts for 0.05 wt% of the total particle mass.

[0171] Step S2, putting the particles obtained in step S1 into an atmosphere furnace, heating to 800°C at 60°C / min in an air atmosphere, and calcining for 24 hours to obtain crystalline silicon oxide powder. Sampling and observation with an electron microscope revealed that there were many irregularly shaped particles in the powder, the powder had a low sphericity, and the particle size distribution of the particles in the powder was wide.

[0172] Comparative Example 2 A powder is provided, and the preparation steps are different from those in Example 1, except that the raw material is amorphous silica spheres prepared by a deflagration method, and the average particle size is 0.7 μm. The preparation is carried out according to the following steps: Step S1, prepare amorphous silica spheres by deflagration method, the average particle size of which is 0.7 μm, add lithium carbonate to the amorphous silica spheres, and mix them evenly, wherein the lithium oxide accounts for 0.05 wt% of the total particle mass.

[0173] Step S2: Put the particles obtained in step S1 into an atmosphere furnace, heat the temperature to 800°C at 60°C / min in an air atmosphere, and calcine for 24 hours to obtain crystalline silicon oxide powder. Sampling and electron microscopy observation show that the powder contains a large number of irregularly shaped particles, the powder has a low sphericity, and the powder particle size distribution is wide. The electron microscopy picture is as follows: Figure 3 shown.

[0174] Comparative Example 3 A powder is provided, and the preparation steps are different from those in Example 1, except that the raw material is amorphous silica spheres prepared by a deflagration method, and the average particle size is 1.3 μm. The preparation is carried out according to the following steps: Step S1, prepare amorphous silica spheres by deflagration method, the average particle size of which is 0.7 μm, add lithium carbonate to the amorphous silica spheres, and mix them evenly, wherein the lithium oxide accounts for 0.05 wt% of the total particle mass.

[0175] Step S2, putting the particles obtained in step S1 into an atmosphere furnace, heating to 800°C at 60°C / min in an air atmosphere, and calcining for 24 hours to obtain crystalline silicon oxide powder. Sampling and electron microscope observation revealed that the powder contained a large number of irregularly shaped particles, the powder had a low sphericity, and the powder had a wide particle size distribution.

[0176] Comparative Example 4 A powder is provided, and the preparation steps are different from those in Example 1, except that the raw material is amorphous silica spheres prepared by a deflagration method, and the added lithium oxide accounts for 0.25wt% of the entire particles. The preparation is performed according to the following steps: Step S1, prepare amorphous silica spheres by deflagration method, the average particle size of which is 1.3 μm, take the amorphous silica spheres and add lithium carbonate, and mix them evenly, wherein, based on lithium oxide, lithium oxide accounts for 0.25 wt% of the entire particles.

[0177] Step S2, putting the particles obtained in step S1 into an atmosphere furnace, heating to 800°C at 60°C / min in an air atmosphere, and calcining for 24 hours. Sampling and electron microscope observation revealed that the powder contained many irregularly shaped particles, the powder had low sphericity, and the powder had a wide particle size distribution.

[0178] Comparative Example 5 A powder is provided, and the preparation steps are different from those in Example 1, except that the raw material is amorphous silica spheres prepared by a deflagration method, the added lithium oxide accounts for 0.25wt% of the entire particles, and a washing step is added. The preparation is performed according to the following steps: Step S1, prepare amorphous silica spheres by deflagration method, the average particle size of which is 1.3 μm, take the amorphous silica spheres and add lithium carbonate, and mix them evenly, wherein, based on lithium oxide, lithium oxide accounts for 0.25 wt% of the entire particles.

[0179] Step S2: Put the particles obtained in step S1 into an atmosphere furnace, raise the temperature to 800° C. at 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0180] Step S3, adding the particles obtained in step S2 into deionized water, stirring and washing for 3 times, and performing solid-liquid separation to obtain a washed filter cake sample.

[0181] Step S4, placing the filter cake in a 120° C. oven and drying it for 8 h, then placing it in an atmosphere furnace, heating it to 800° C. in an air atmosphere, and heat treating it for 24 h.

[0182] Comparative Example 6 A powder is provided, and the preparation steps are different from those in Example 1, except that the raw material is amorphous silica spheres prepared by a deflagration method, the added lithium oxide accounts for 0.25wt% of the entire particle, a cleaning step is added, and the calcination and heat treatment temperature is 1100°C. The preparation is performed according to the following steps: Step S1, prepare amorphous silica spheres by deflagration method, the average particle size of which is 1.3 μm, take the amorphous silica spheres and add lithium carbonate, and mix them evenly, wherein, based on lithium oxide, lithium oxide accounts for 0.25 wt% of the entire particles.

[0183] Step S2: Put the particles obtained in step S1 into an atmosphere furnace, raise the temperature to 1100° C. at a rate of 60° C. / min in an air atmosphere, and calcine for 24 hours.

[0184] Step S3, adding the particles obtained in step S2 into deionized water, stirring and washing for 3 times, and performing solid-liquid separation to obtain a washed filter cake sample.

[0185] Step S4, placing the filter cake in a 120° C. oven and drying it for 8 h, then placing it in an atmosphere furnace, heating it to 800° C. in an air atmosphere, and heat treating it for 24 h.

[0186] Performance Testing The powders prepared in Examples 1 to 21 and Comparative Examples 1 to 5 were tested for total lithium content (total lithium content), mass percentage of α-quartz crystals (quartz content), mass percentage of cristobalite (cristobalite content), moisture content, sphericity under 20 μm sieve of the powder, and interfacial peeling strength. The results are shown in Tables 1 and 2. ND means not detected. For the detection of free lithium content, ND can be regarded as a detection content of 0.

[0187] Table 1 Calcination temperature / ℃ Calcination heating rate (℃ / min) Set the percentage of particles connected to the depressions / % Maximum width of connection depression / nm α-quartz content / % Cristobalite content / % Interface peel strength / (N / cm) Example 1 800 60 90% 146 91% 0 7.9 Example 2 800 20 50% 14 92% 0 6.0 Example 3 800 25 60% 20 91% 0 6.1 Example 4 800 30 67% 54 92% 0 6.3 Example 5 800 40 86% 83 91% 0 6.4 Example 6 800 50 95.1% 119 90% 0 7.5 Example 7 800 70 100% 168 92% 0 8.8 Example 8 800 After the atmosphere furnace is preheated, the pellets are placed directly into the furnace 100% 180 93% 0 8.2 Example 9 1100 After the atmosphere furnace is preheated, the pellets are placed directly into the furnace 100% 189 94% 4.5% 5.4 Example 10 720 60 66% 78 82% 1.0% 6.0 Embodiment 11 900 60 96% 148 93% 3.5% 6.4 Example 12 1100 60 98% 160 93% 4.6% 6.7 Example 13 800 60 93% 145 92% 0 7.8 Embodiment 14 800 60 92% 143 90% 0 7.4 Embodiment 15 800 60 93% 142 94% 0 7.5 Example 16 800 60 94% 145 96% 0 7.6 Embodiment 17 800 60 92% 143 90% 0 7.2 Embodiment 18 800 60 94% 145 91% 0 8.3 Embodiment 19 800 60 93% 148 91% 0 8.9 Comparative Example 1 800 60 28% 57 76% 0 4.0 Comparative Example 2 800 60 25% 32 75% 0 3.6 Comparative Example 3 800 60 26% 59 76% 0 4.2 Comparative Example 4 800 60 27% 62 85% 0 4.5 Comparative Example 5 800 60 27% 63 86% 0 4.8 Comparative Example 6 1100 60 42% 78 30% 64.3% 1.8 Table 2 Average particle size of raw material particles / μm Sphericity Moisture content / ppm Total lithium content / ppm Free lithium content / ppm Example 1 1.3 0.94 295 256 10 Example 2 1.3 0.93 312 258 11 Example 3 1.3 0.94 318 260 10 Example 4 1.3 0.93 316 260 12 Example 5 1.3 0.94 306 258 11 Example 6 1.3 0.93 315 256 12 Example 7 1.3 0.93 319 258 13 Example 8 1.3 0.93 284 260 12 Example 9 1.3 0.90 216 257 9 Example 10 1.3 0.92 248 248 6 Embodiment 11 1.3 0.91 239 244 4 Example 12 1.3 0.90 214 246 5 Example 13 1.3 0.93 284 200 ND Embodiment 14 1.3 0.93 276 195 ND Embodiment 15 1.3 0.94 349 1250 14 Example 16 1.3 0.93 398 5000 28 Embodiment 17 0.3 0.90 382 258 14 Embodiment 18 5.0 0.95 101 256 9 Embodiment 19 10.0 0.96 83 260 7 Comparative Example 1 1.0 0.78 427 253 33 Comparative Example 2 0.7 0.70 512 258 33 Comparative Example 3 1.3 0.79 412 251 32 Comparative Example 4 1.0 0.76 674 1300 148 Comparative Example 5 1.0 0.78 600 1260 81 Comparative Example 6 1.0 0.63 598 1255 78 From Table 1 and Table 2, we can see that: (1) The present invention uses spherical polysiloxane particles formed by methyltrimethoxysilane as the starting point, and calcining to prepare crystalline silicon oxide powder. Compared with the traditional deflagration method for preparing crystalline silicon oxide powder, the present invention has a higher crystallinity of α-quartz crystals, and the mass proportion of α-quartz crystals in the powder can reach 80%, and the average sphericity of the silicon oxide powder obtained by sieving through a 20μm sieve is above 0.9. In particular, compared with the crystalline silicon oxide powder currently on the market, the present invention sets at least one connection depression on the surface of at least 50% of the particles in the spherical crystalline silicon oxide powder, and the maximum width of the connection depression is less than 180nm under the observation of a non-gold spraying field emission electron microscope. By setting the connection depression on the surface of the particles in the powder, the connection strength between the powder and the connection material is enhanced, and the peeling strength between the packaging film material and the copper foil layer made of the spherical crystalline silicon oxide powder as a filler can be increased, thereby solving the problem of low interface peeling strength caused by the presence of quartz crystals. The powder of the present invention is used as a filler to prepare a packaging film material, so that the packaging film material and the copper foil coating have excellent bonding strength.

[0188] It can be seen from Example 9 that the maximum width of the connection depression is 189 nm, the mechanical interlocking strength between the powder particles and the connection material caused by the connection depression is insufficient, and the mechanical anchoring effect is small, which ultimately leads to poor connection strength between the powder particles and the resin and copper foil layer.

[0189] Furthermore, the present invention has found that the maximum width of the connection depression set on the surface of the silicon oxide powder particles prepared by the present invention is less than 180nm, which can make the bonding force between the packaging film material and the copper foil coating better and the peeling strength greater. The preparation of the connection depression is an integrated preparation of the present invention when preparing crystalline silicon oxide particles. This is because the present invention uses spherical polysiloxane particles as the raw material for preparing α-quartz crystal powder, so the connection depression can be prepared. When polysiloxane particles are calcined, two reactions will occur simultaneously. One is that siloxane is converted into silicon dioxide, and the other is that siloxane is directly converted into α-quartz crystals under the action of lithium elements. Since there is a volume difference between the material transformations of these two reactions, the connection depression is formed. The connection depression can be regulated by the calcination process. When the polysiloxane particles containing lithium elements are directly placed in a high-temperature calcination furnace, the heating rate is faster, and the width of the surface connection depression obtained is larger.

[0190] The crystalline silicon oxide powder prepared by the present invention has a low hydroxyl content. The low hydroxyl content can reduce the affinity of the product of the spherical crystalline silicon oxide powder with moisture in the air, and has the property of not being easy to absorb water. The product finally shows that the moisture content is low after being placed. Therefore, it is not difficult to see from the low moisture content of the spherical crystalline silicon oxide powder that even if the surface of the spherical crystalline silicon oxide powder particles is provided with connecting depressions, the amount of water adsorbed is small and the water adsorption performance is low. This shows that the spherical crystalline silicon oxide powder should have a dense structure, so it is difficult to absorb moisture in the air. The powder is used as a filler for packaging materials, which has the excellent performance of low dielectric loss.

[0191] (2) From the comparative analysis of Comparative Example 1 and Example 1, it can be seen that in the preparation method of the present invention, under the same amount of lithium element addition, Comparative Example 1 uses amorphous silicon dioxide as a raw material for calcination, and the crystallinity of the α-quartz crystal of Comparative Example 1 is greatly reduced compared with Example 1. Since the starting raw material of Example 1 is polysiloxane, it becomes silicon dioxide after calcination, and its particle size will be reduced to 1.0 μm, so Comparative Examples 1, Comparative Examples 4, Comparative Examples 5, and Comparative Examples 6 use silicon dioxide as a raw material for calcination, and the average particle size of the raw material is selected to be 1.0 μm, so that the average particle size of the product powder particles of Example 1 is the same as that of Comparative Examples 1, Comparative Examples 4, Comparative Examples 5, and Comparative Examples 6. Compared with Comparative Example 1, after adding the lithium source, the content of free lithium in the product particles of Comparative Example 4 is greatly increased. Compared with Comparative Example 4, Comparative Example 5 further adds a cleaning step, but the free lithium content of Comparative Example 5 is not effectively reduced, and is still much higher than the free lithium content of Comparative Example 1. Compared with Comparative Example 1, Comparative Example 6 increases the amount of lithium source added and raises the calcination temperature to 1100°C. It can be seen that the cristobalite content of Comparative Example 6 increases significantly, reaching 64.3%. Using this as filler, the peel strength of the packaging film material and the copper foil coating will be greatly reduced after high-temperature treatment at 200~300°C. At this time, the peel strength is only 1.8N / cm.

[0192] In order to verify the effect of the particle size of the raw material on the preparation method using amorphous silicon dioxide as the raw material for calcination, Comparative Examples 2 and 3 were calcined using amorphous silicon dioxide with an average particle size of 0.7 μm and 1.3 μm as the raw material, respectively. The results showed that the crystallinity of α-quartz crystals in the products of Comparative Examples 2, 3 and 1 was basically the same, and was much lower than that in Example 1.

[0193] The raw materials and equipment used in the present invention, unless otherwise specified, are all commonly used raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art.

[0194] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A spherical crystalline silicon oxide powder, characterized in that: Calculated by the number of particles, at least 50% of the particles in the silicon oxide powder have at least one connection depression on their surfaces for enhancing the connection strength between the powder and the connecting material; under observation by a field emission electron microscope without gold spraying, the maximum width of the connection depression is less than 180 nm.

2. The spherical crystalline silicon oxide powder according to claim 1, characterized in that: The mass proportion of α-quartz crystals in the silicon oxide powder is more than 80%.

3. The spherical crystalline silicon oxide powder according to claim 1, characterized in that: The silicon oxide powder obtained by sieving through a 20 μm sieve has an average sphericity of 0.9 or more.

4. The spherical crystalline silicon oxide powder according to claim 1, characterized in that: The content of free lithium in the silicon oxide powder is below 30 ppm.

5. The spherical crystalline silicon oxide powder according to claim 1, characterized in that: The content of free lithium in the silicon oxide powder is below 15 ppm.

6. The spherical crystalline silicon oxide powder according to claim 1, characterized in that: The mass proportion of cristobalite crystals in the silicon oxide powder is no more than 5%.

7. The spherical crystalline silicon oxide powder according to claim 1, characterized in that: The average particle size of the silicon oxide powder is 0.3-10 μm.

8. The spherical crystalline silicon oxide powder according to claim 1, characterized in that: Under the environmental conditions of 25° C. and 50% RH, the 200° C. Karl Fischer moisture content of the spherical crystalline silicon oxide powder after being placed for 24 hours is not higher than 400 ppm.

9. A substrate film material, characterized in that: A spherical crystalline silicon oxide powder comprising a resin matrix and any one of claims 1 to 8 dispersed therein; the connection depressions on the surface of the powder particles enhance the interfacial bonding strength between the powder and the resin matrix through a mechanical anchoring effect and a specific surface area increase effect, and enable the peel strength between the substrate film material and the copper foil coated on its surface to reach 6.0 N / cm or more.

10. The substrate film material according to claim 9, characterized in that: The added amount of the powder is 30% to 80% of the total mass of the substrate film material.

11. A substrate film material according to claim 9 or 10, characterized in that: The resin is selected from one or more of epoxy resin, cyanate resin, polyphenylene ether resin and hydrocarbon resin.

12. The substrate film material according to claim 9, characterized in that: The substrate film material or the copper foil is roughened, and the peeling strength is improved in coordination with the powder depression.

13. A method for preparing spherical crystalline silicon oxide powder, characterized in that: The following steps are involved: The spherical polysiloxane particles are mixed with a lithium source and then calcined to obtain a product.

14. The preparation method according to claim 13, characterized in that: The spherical polysiloxane includes T units, wherein the T units are R1SiO3 - , R1 is a hydrocarbon group having 1 to 18 carbon atoms or a hydrogen atom.

15. The preparation method according to claim 13, characterized in that: The calcination temperature is 720-1100°C.

16. The preparation method according to claim 13 or 16, characterized in that: The calcination time is 7 to 30 hours.

17. The preparation method according to claim 13, characterized in that: The calcination is performed under an air gas atmosphere.

18. The preparation method according to claim 13, characterized in that: Also includes the steps: washing the calcined product; The cleaned product is heat treated.

19. The preparation method according to claim 18, characterized in that: The cleaning method comprises: adjusting the pH of water to be neutral or acidic, and then adding the water into the calcined product to clean it, and the cleaning temperature is 20° C. to 300° C.

20. The preparation method according to claim 18, characterized in that: The temperature of the heat treatment is 60-1100°C.

21. Use of the spherical crystalline silicon oxide powder according to any one of claims 1 to 8, or the spherical crystalline silicon oxide powder prepared by the preparation method according to any one of claims 13 to 20 in preparing semiconductor packaging materials or substrate materials.

Images