CN115697907A - Spherical crystalline silica particles and method for producing same - Google Patents
Spherical crystalline silica particles and method for producing same Download PDFInfo
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- CN115697907A CN115697907A CN202180036714.6A CN202180036714A CN115697907A CN 115697907 A CN115697907 A CN 115697907A CN 202180036714 A CN202180036714 A CN 202180036714A CN 115697907 A CN115697907 A CN 115697907A
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/18—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
- H01L23/29—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the material, e.g. carbon
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
- H01L23/31—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/30—Particle morphology extending in three dimensions
- C01P2004/32—Spheres
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
Abstract
Spherical crystalline silica particles having a high crystallization ratio and a high proportion of quartz, while suppressing the contents of alkali metals and alkaline earth metals to a low level, and a method for producing the same. Spherical crystalline silica particles: the circularity is more than 0.80; contains 0.02 mass% or more and less than 0.40 mass% of lithium in terms of oxide, and 0.004 mass% or more and less than 1.0 mass% of calcium in terms of oxide; a phase containing crystalline silica; the spherical crystalline silica particles have a crystalline silica phase proportion of 40.0% or more and a crystalline silica phase proportion of 80.0% or more by mass.
Description
Technical Field
The present invention relates to spherical crystalline silica particles and a method for producing the same, and particularly to spherical crystalline silica particles having a high quartz ratio and a method for producing the same.
Background
As the amount of information increases with the improvement of communication technology, and the use of millimeter wave bands such as millimeter wave radars is rapidly expanding, the frequency is increasing at high frequencies. The circuit board for transmitting these high-frequency signals is composed of electrodes as a circuit pattern and a dielectric substrate. In order to suppress energy loss at the time of transmission of a high-frequency signal, the dielectric loss tangent (tan δ) of the dielectric material must be small. To achieve low dielectric losses, the dielectric material must have low polarity and low dipole moment.
As the dielectric material, ceramic particles, resin, and a composite of these are mainly used. Particularly, as the use of millimeter wave bands has been expanded in recent years, ceramic particles and resins having a lower dielectric loss tangent (tan δ) have been required. The resin is suitable for high-frequency devices having a relatively small relative dielectric constant (. Epsilon.r), but has a larger dielectric loss tangent (tan. Delta.) or thermal expansion coefficient than the ceramic particles. Therefore, in the composite of ceramic particles and resin for millimeter wave band, it is suitable for (1) making the ceramic particles themselves low in dielectric loss tangent (tan δ) and (2) highly filling the ceramic particles, thereby reducing the amount of resin exhibiting a large dielectric loss tangent (tan δ).
As the ceramic particles, silica (SiO) is generally used 2 ) And (3) granules. DioxygenIf the shape of the silicon particles is angular, the fluidity, dispersibility, and filling property in the resin are deteriorated, and the abrasion of the production apparatus is accelerated. To improve this, spherical silica particles are widely used. It is considered that the closer spherical silica particles are to a regular spherical shape, the more the filling property, fluidity, and wear resistance and abrasion resistance in the resin can be improved, and therefore particles having a high circularity have been desired. Further, studies have been made to optimize the particle size distribution of the particles and further improve the packing property.
In general, as a method for producing spherical silica, a melt-blowing method is used. In melt blowing, particles are melted by passing them through a high-temperature region such as a flame, and the shape of the particles becomes spherical due to surface tension. The molten and spheroidized particles are carried by a gas flow and recovered, thereby preventing the particles from being fused with each other, and the melt-blown particles are quenched. Since the silicon dioxide is rapidly cooled from the molten state, the silicon dioxide is not crystallized, but is formed into glass-like particles having an amorphous (amorphous) structure, which are generally formed into quartz glass.
Since spherical silica particles produced by the melt-blowing method are amorphous, their thermal expansion coefficient and thermal conductivity are low. The amorphous silica particles had a thermal expansion coefficient of 0.5ppm/K and a thermal conductivity of 1.4W/mK. These properties are substantially the same as the thermal expansion coefficient of quartz glass having no crystalline structure and an amorphous (amorphous) structure. In general, since Si, which is a main material of an IC chip, has a thermal expansion coefficient of 3 to 5ppm/K and a sealing resin for sealing the IC chip has a thermal expansion coefficient much larger than that of Si, the IC chip is warped due to a difference in thermal expansion behavior between the two materials (Si and sealing resin), thereby affecting the generation. On the other hand, when spherical silica having a small thermal expansion coefficient is highly filled in a resin having a large thermal expansion coefficient, an effect of reducing the thermal expansion of the sealing material (composite of the spherical silica and the resin) itself can be obtained. By setting the thermal expansion coefficient of the sealing material to a value close to Si, deformation due to thermal expansion behavior when the IC chip is sealed can be suppressed.
As described above, the silica particles for sealing materials are required to have excellent dielectric properties at high frequencies in the millimeter wave band, in addition to filler properties, flowability, abrasion resistance, and the like, which are required to be blended in a large amount into a resin so as to maintain the performance as a composite. Since the dielectric properties are physical properties of the material, it is difficult to reduce the dielectric loss tangent of the amorphous silica particles.
Patent document 1 describes a method for producing a porous powder having a main crystal phase made of quartz, which is characterized by adding 0.5 mass% or more of a Zn compound in terms of ZnO to a silica gel having an average particle size of 0.1 to 20 μm and heat-treating the mixture at 900 to 1100 ℃.
Patent document 2 discloses a method for producing spherical crystalline silica particles, characterized by comprising a step of heat-treating spherical silica particles at 800 to 1300 ℃ and cooling the heat-treated spherical silica particles, wherein the cooled spherical silica particles have a crystal phase of 90 mass% or more and the crystal phase of the whole quartz crystal is 70 mass% or more, and the spherical silica particles are mixed as follows: the amorphous spherical silica particles are mixed with the alkali metal compound in a proportion of 0.4 to 5% by mass in terms of oxide with respect to the total mass of the amorphous spherical silica particles and the mass of the alkali metal particles in terms of oxide, or the alkaline earth metal oxide is mixed in a proportion of 1 to 5% by mass in terms of oxide with respect to the total mass of the amorphous spherical silica particles and the mass of the alkaline earth metal particles in terms of oxide. When the amount of the alkali metal added is less than 0.4 mass% and the amount of the alkaline earth metal added is less than 1 mass%, the occurrence of quartz is lowered.
In non-patent document 1, the influence of an additive on crystallization and phase transition is studied by systematically adding an alkali metal oxide to a synthetic amorphous spherical silica, forming the resultant into a granular form, and then performing heat treatment. It is known from this that the additive is lithium oxide (Li) 2 O), when 0.5 mass% or more is added and fired at 800 ℃ or higher, quartz can be obtained.
In non-patent document 2, the influence of cations on crystallization and phase transition of a silica substance is examined. It is disclosed therein that when LiCl is added to synthetic amorphous silica in an amount of 10% by mass and heat treatment is performed at 800 ℃, quartz appears as an optimum phase.
Documents of the prior art
Patent document
Patent document 1: JP 2002-20111A
Patent document 2: international publication No. 2018/186308
Non-patent document
Non-patent document 1: journal of Ceramics Society of Japan 105[5]385-390 (1997)
Non-patent document 2: the university of the island of deer, ministry of science, geology, biology 24 vol 1-22 (1991)
Non-patent document 3: high Pressure Research 28 (4) 641-650 (2008)
Disclosure of Invention
Technical problem to be solved by the invention
The present invention aims to: there is a need for filler particles for semiconductor encapsulation having excellent dielectric characteristics at frequencies in the millimeter wave band of 30 to 80GHz, and for resin composites for high-frequency devices prepared by mixing the filler particles into a resin. As a result, it has been found that, in order to obtain a resin composite having a low dielectric loss tangent, first, spherical molten (amorphous) silica is crystallized by heat treatment, which is very effective. That is, it was confirmed that the dielectric loss tangent of crystalline silica in the millimeter wave band (30 GHz to 80 GHz) is significantly lower than that of amorphous silica which has been widely used. As a result, the spherical crystalline silica particles are silica particles exhibiting excellent dielectric characteristics for high-frequency device applications. The crystalline silica obtained by the heat treatment is quartz, cristobalite or a mixture thereof. Since quartz and cristobalite have different physical property values, when used as a filler, the phase of crystalline silica is preferably a single phase.
Further, when cristobalite is crystallized, the cristobalite has a thermal expansion coefficient 3 times or more as high as that before heat treatment, and further has an inflection point in the vicinity of 250 ℃. In particular, when used as a filler for sealing a semiconductor, peeling occurs at the interface between the original and the sealing material due to mismatch with the thermal expansion behavior of the semiconductor original. Quartz with an inflection point of thermal expansion outside the assembly temperature range among crystalline silica is suitable for this purpose. When quartz is used as a filler for sealing a semiconductor, it is possible to reduce the dielectric loss and to improve the mounting reliability while achieving an appropriate thermal expansion coefficient.
As a method for obtaining quartz by crystallizing spherical amorphous silica, patent document 1 discloses: the zinc compound is added in an amount of 0.5 mass% or more in terms of oxide, and the mixture is heat-treated at 900 to 1100 ℃. However, as a result of a reproduction test, the present inventors have found that amorphous silica is not crystallized at a heat treatment temperature of 950 ℃ or lower. When the heat treatment is performed at a temperature exceeding 950 ℃, crystallization starts, but the degree of crystallization stops at about 20% even at 1100 ℃. And the crystal phase appears to be cristobalite as the main phase, and the single phase of quartz cannot be obtained at high content.
Patent document 2 discloses a method for producing spherical crystalline silica particles, which is characterized by comprising the steps of: mixing 1 to 5 mass% of an alkaline earth metal in terms of oxide with respect to the total mass in terms of oxide, heat-treating the mixed spherical silica particles at 800 to 1300 ℃, and cooling the heat-treated spherical silica particles; the spherical silica particles after cooling have a crystal phase of 90 mass% or more, and the quartz crystals account for 70 mass% or more of the whole. In the examples, calcium is shown as an alkaline earth metal, but in the case of comparative example, in which calcium is added in an amount of 0.5 mass% in terms of oxide, and heat treatment is performed at 1100 ℃, quartz appears as low as less than 30%. In addition, when calcium is added in an amount of less than 1 mass% in terms of oxide, spherical crystalline silica having a high quartz content has not been obtained.
In patent document 2, non-patent document 1, and non-patent document 2, lithium is shown as a quartz crystallization promoting element in the same manner. Patent document 2 discloses mixing lithium at a ratio of 0.4 to 5 mass% in terms of oxide, and performing a heat treatment at 800 to 1300 ℃. Non-patent document 1 shows that quartz can be obtained by adding 0.5 mass% or more of lithium oxide to synthetic amorphous spherical silica and firing the mixture to 800 ℃. Further, non-patent document 2 shows that when 10 mass% of lithium chloride (LiCl) is added to synthetic amorphous silica and heat treatment is performed at 800 ℃, quartz appears as the most advantageous phase.
However, an alkaline earth metal such as calcium or an alkali metal such as lithium is not preferable as an element to be added to the semiconductor sealing material. From the viewpoint of maintaining the normal operation and mounting reliability of semiconductor elements, it is necessary to reduce the amount of alkaline earth metal and alkali metal elements added.
As factors affecting crystallization of amorphous silica, temperature, pressure, and impurity elements are known. As for the influence of pressure, for example, non-patent document 3 describes that quartz is crystallized when heat treatment is performed at 300 to 1200 ℃ under 2 to 3 ten thousand atmospheric pressures, but a pressurizing device of several ten thousand atmospheric pressures is not preferable because it has a limit in throughput and is difficult to perform industrial mass production. Although many crystallization experiments have been reported so far, in which temperature and impurity elements are used as a fluctuation factor, spherical crystalline silica having a crystalline silica content of 40% or more and a quartz content of 80% or more by mass has not been obtained. From the viewpoint of maintaining the normal operation and mounting reliability of semiconductor devices, it is desired to obtain silica particles which are reduced in lithium and calcium to less than 0.40 mass% and less than 1.0 mass%, respectively, in terms of oxides, have a high crystallization ratio, and are substantially composed of a single crystal of quartz.
The present invention aims to provide: spherical silica particles suitable for use as a filler for semiconductor sealing materials having excellent dielectric characteristics in the millimeter wave band, that is, spherical crystalline silica particles having a high crystallization rate and a high proportion of quartz while suppressing the contents of alkali metals and alkaline earth metals to a low level, and a method for producing the same.
Means for solving the problems
The present inventors have conducted intensive studies to solve the problems. As a result, a mixed raw material powder in which a calcium raw material containing 0.004 to less than 1.0 mass% of calcium in terms of oxide and a lithium raw material containing 0.02 to less than 0.40 mass% of lithium in terms of oxide are mixed with a powder composed of amorphous silica particles having a circularity of 0.80 or more is heated at a heat treatment temperature of 850 to 1150 ℃. Without being bound to a particular theory, it is believed that the simultaneous addition of lithium metal and calcium metal to silica exerts a synergistic effect on the crystallization of quartz, and the crystallization of quartz is promoted in spite of the reduction in the addition amount as compared with the case where each element is added alone. The crystalline silica particles obtained by the heat treatment at 850 to 1150 ℃ contain a crystalline silica phase which is substantially a single phase of quartz. The single phase herein means that the proportion of quartz in the crystalline silica phase is 80 mass% or more, preferably 85.0 mass% or more, and more preferably 90.0 mass% or more.
The present invention provides the following spherical silica particles and a method for producing the same.
(1) Spherical crystalline silica particles: a phase having a circularity of 0.80 or more, containing 0.02 to less than 0.40 mass% of lithium in terms of oxide, containing 0.004 to less than 1.0 mass% of calcium in terms of oxide, and containing crystalline silica; the ratio of the crystalline silica phase in the spherical crystalline silica particles is 40.0% or more, and the ratio of quartz in the crystalline silica phase is 80.0% or more by mass.
(2) The spherical crystalline silica particles according to the above (1), wherein the ratio of the phase of the crystalline silica is 70.0% or more, and the ratio of the quartz in the phase of the crystalline silica is 85.0% or more by mass.
(3) The spherical crystalline silica particles according to the above (2), wherein the ratio of the phase of the crystalline silica is 80.0% or more, and the ratio of the quartz in the phase of the crystalline silica is 90.0% or more by mass.
(4) The spherical crystalline silica particles according to any one of the above (1) to (3), wherein the average particle diameter (D50) is 3 to 100. Mu.m.
(5) The method for producing spherical crystalline silica particles according to any one of (1) to (4), comprising: a mixed raw material powder obtained by mixing a calcium raw material and a lithium raw material into spherical amorphous silica particles having a circularity of 0.80 or more is heat-treated at 850 to 1150 ℃.
(6) The method for producing spherical crystalline silica particles according to any one of (1) to (4), comprising:
a mixed raw material powder obtained by mixing a lithium raw material into spherical amorphous silica particles having a circularity of 0.80 or more and containing a calcium component is heat-treated at 850 to 1150 ℃.
(7) The method for producing spherical crystalline silica particles according to any one of (1) to (4), comprising:
a mixed raw material powder obtained by mixing a calcium raw material with spherical amorphous silica particles having a circularity of 0.80 or more and containing a lithium component is heat-treated at 850 to 1150 ℃.
(8) The method for producing spherical crystalline silica particles according to any one of (1) to (4), comprising:
spherical amorphous silica particles having a circularity of 0.80 or more and containing a calcium component and a lithium component are heat-treated at 850 to 1150 ℃.
(9) The method for producing spherical crystalline silica particles according to any one of (5) to (8), wherein the heat treatment temperature is 875 ℃ to 1110 ℃.
Effects of the invention
According to the present invention, there can be provided: spherical silica particles which are suitable for use as a filler for semiconductor sealing materials having excellent dielectric characteristics in the millimeter wave band, that is, spherical crystalline silica particles having a high crystallization rate and a high proportion of quartz while suppressing the contents of alkali metals and alkaline earth metals to a low level, and a method for producing the same.
Drawings
Fig. 1 shows XRD patterns of amorphous silica before heat treatment and silica (after heat treatment) which is one embodiment of the present invention.
Detailed Description
The spherical crystalline silica according to one embodiment of the present invention is spherical crystalline silica particles including: a phase having a circularity of 0.80 or more, containing 0.02 mass% or more and less than 0.40 mass% of lithium in terms of oxide, containing 0.004 mass% or more and less than 1.0 mass% of calcium in terms of oxide, and containing crystalline silica; the ratio of the crystalline silica phase in the spherical crystalline silica particles is 40.0% or more, and the ratio of quartz in the crystalline silica phase is 80.0% or more by mass. The crystalline silica phase of 40.0% or more as used herein means the proportion of the crystalline silica phase in the spherical crystalline silica particles, and the method of obtaining the same will be described later.
As silicon dioxide (SiO) 2 ) The crystal structure of (2) includes cristobalite and quartz. Silica having these crystalline structures has higher thermal conductivity than amorphous silica. Therefore, in the semiconductor sealing filler, the heat dissipation of the IC chip can be improved by replacing amorphous silica with crystalline silica in an appropriate amount. Further, since the dielectric loss tangent of crystalline silica in the millimeter wave band is lower, the more amorphous silica is replaced with crystalline silica in the semiconductor encapsulating filler, the lower the dielectric loss tangent of the semiconductor encapsulating material.
[ Process for producing spherical crystalline silica particles ]
The spherical crystalline silica particles of the present invention can also be produced by mixing spherical amorphous silica with both a calcium raw material and a lithium raw material and heat-treating the mixture (also referred to as a mixed raw material).
According to one embodiment, the lithium ion secondary battery can be produced by mixing a lithium raw material with spherical amorphous silica particles containing a calcium component and heat-treating the resulting mixture.
Alternatively, the lithium ion secondary battery can be produced by mixing a calcium raw material with spherical amorphous silica particles containing a lithium component to obtain a mixed raw material and subjecting the mixed raw material to a heat treatment.
Alternatively, the particles can be produced by heat-treating spherical amorphous silica particles containing a calcium component and a lithium component.
(spherical amorphous silica particles)
The amorphous spherical silica particles as a raw material can be produced by a method such as a melt-blowing method. In the melt-blowing method, natural silica powder pulverized and adjusted to a desired particle size is passed through a flame to melt the particles, and the shape of the particles becomes spherical due to surface tension. Thus, spherical amorphous silica particles having a circularity of 0.80 or more can be produced by the melt-blowing method.
The main component of the composition of the spherical amorphous silica particles is silica, and the spherical crystalline silica particles to be finally obtained are not particularly limited as long as they are within a desired range. In one embodiment, the spherical amorphous silica particles may have a composition of: 98.0% by mass or more of silicon dioxide (SiO) 2 ) Further, the trace elements may include Ca, li, al, na, mg, ba, zn, and the like. In one embodiment, the spherical amorphous silica particles may have a composition containing Zn in an amount of less than 0.5 mass%.
(calcium material)
The calcium raw material is mixed with spherical amorphous silica particles and subjected to heat treatment. The composition and the amount to be mixed of the calcium raw material are not particularly limited, and can be appropriately adjusted as long as the spherical crystalline silica particles to be finally obtained are within a desired range. The calcium material may be calcium hydroxide or calcium oxide which is stably present in the atmosphere, or may be a natural mineral. The calcium raw material may be added in the form of powder or an aqueous solution so that the calcium raw material can be uniformly mixed with the spherical amorphous silica particles. At least a part of the calcium raw material may be a trace element contained in the spherical amorphous silica particles. For example, spherical amorphous silica particles can be used as a calcium source material as long as the spherical amorphous silica particles contain sufficient calcium and the desired calcium content is achieved in the finally obtained spherical crystalline silica particles. In addition, in the case where the spherical amorphous silica particles contain insufficient calcium, a calcium raw material may be added to obtain a desired calcium content in the finally obtained spherical crystalline silica particles.
(lithium raw material)
A lithium raw material is mixed with spherical amorphous silica particles and subjected to heat treatment. The composition and the amount to be mixed of the lithium raw material are not particularly limited, and may be appropriately adjusted as long as the spherical crystalline silica particles to be finally obtained are within a desired range. The lithium raw material is an oxide, oxycarbide, hydroxide, nitroxide, or the like, and the form of addition is not particularly limited. The amorphous spherical silica particles may be added in the form of powder or aqueous solution for uniform mixing. In addition, at least a part of the lithium raw material may be a trace element contained in the spherical amorphous silica particles. For example, spherical amorphous silica particles can be used as a lithium raw material as long as the spherical amorphous silica particles can contain sufficient lithium and the finally obtained spherical crystalline silica particles have a desired lithium content. In addition, in the case where the spherical amorphous silica particles contain lithium but are insufficient, a calcium raw material may be added so that the spherical crystalline silica particles finally obtained can have a desired lithium content.
(mixing)
Spherical amorphous silica particles are mixed with both a calcium raw material and a lithium raw material. The calcium material and/or the lithium material may be contained in spherical amorphous silica. The method of mixing is not particularly limited as long as the raw materials in the mixture are uniformly dispersed and mixed. The mixing may be performed by a powder mixer. By mixing, the calcium material and the lithium material come into contact with at least a part of the spherical amorphous silica, and crystallization of the spherical amorphous silica, particularly crystallization into quartz, is promoted in the subsequent heat treatment step.
In the mixing, the raw materials are mixed so that lithium contained in the produced spherical crystalline silica particles is 0.02 mass% or more and less than 0.40 mass% in terms of oxide and calcium contained is 0.004 mass% or more and less than 1.0 mass% in terms of oxide. Since the total amount of the lithium raw material or the calcium raw material which is not blended is contained in the produced spherical crystalline silica particles, it is preferable to blend the lithium raw material or the calcium raw material in consideration of the content ratio.
Since the mixing brings the calcium material and the lithium material into contact with at least a part of the spherical amorphous silica, the pulverization of the spherical amorphous silica is not promoted, and thus the circularity thereof hardly decreases before and after the mixing.
(Heat treatment)
The temperature of the mixed raw material obtained by mixing the spherical amorphous silica particles, the calcium raw material and the lithium raw material is in the range of 850 to 1150 ℃ for heat treatment. The atmosphere during the heat treatment may be an oxidizing atmosphere such as the atmosphere or an inert gas atmosphere such as nitrogen or argon. The atmospheric pressure is preferably atmospheric pressure because heat treatment is industrially carried out in large quantities. When the heat treatment temperature is less than 850 ℃, crystallization cannot proceed or crystallization is significantly slowed. On the other hand, if the temperature is higher than 1150 ℃, crystallization of cristobalite proceeds competitively with crystallization of quartz. As a result, substantially single-phase spherical crystalline silica particles of quartz cannot be obtained. Here, the substantial single phase means a state in which 80 mass% or more of the crystalline silica phase contained in the spherical crystalline silica particles is in a quartz phase. The preferred heat treatment temperature is 875 ℃ to 1110 ℃.
The time of the heat treatment may be appropriately adjusted to obtain a desired degree of crystallinity. When lithium element and calcium element are uniformly and simultaneously present in the spherical amorphous silica particles, the spherical amorphous silica particles can be more quartz-crystallized by the synergistic effect of both elements than when a single element is present. In one embodiment of the present invention, lithium may be added as a lithium raw material (lithium carbonate or the like) during mixing, or may be contained in advance in spherical amorphous silica particles. The calcium may be supplied as a calcium raw material (calcium oxide or the like) at the time of mixing, or may be contained in advance by spherical amorphous silica particles. In order to allow the lithium or calcium to uniformly exist in the spherical amorphous silica particles by diffusion in the heating step, it is considered that the entire spherical amorphous silica particles are crystallized into quartz. Therefore, the longer the heat treatment time, the more lithium or calcium diffuses into the spherical amorphous silica particles, and the more the crystallization proceeds. Typically, in other words, when the temperature increase/decrease rate is larger than 60 ℃/hr, the progress of crystallization is actually determined by the heat treatment temperature, that is, the holding time at the maximum temperature, and therefore, the crystallization can be controlled by adjusting the holding time at the maximum temperature. In this case, the heat treatment time may be adjusted within a range of approximately 1 hour to 48 hours, and may be 3 hours or more, or 6 hours or more, from the viewpoint of sufficiently promoting crystallization. Further, since the degree of crystallization is saturated even if the heat treatment time is excessively extended, the heat treatment time may be 25 hours or less, 18 hours or less, or 12 hours or less from the viewpoint of cost reduction.
When the heat treatment temperature is high, the diffusion coefficient of lithium element in the spherical amorphous silica particles increases, and the crystallization of quartz progresses. However, if it exceeds 1150 ℃, the cristobalite phase competitively appears, and quartz becomes no longer a single phase, so that there is an upper limit to the heat treatment temperature.
The degree of diffusion varies depending on the type and amount of the lithium raw material or calcium raw material, and therefore, the heat treatment time and temperature can be appropriately selected.
In the case of heat treatment in an electric furnace, the rate of temperature rise or the rate of cooling does not greatly affect the appearance of spherical crystalline silica particles.
The circularity of the spherical crystalline silica of the present invention hardly decreases before and after the heat treatment for crystallization. The spherical crystalline silica particles of the present invention become crystalline at a relatively low temperature in the heat treatment at 850 to 1150 ℃, and the circularity hardly decreases in this temperature range. When the temperature exceeds 1100 ℃, amorphous silica particles may be bonded by fusion or sintering, and since the spherical crystalline silica particles of the present invention are crystalline (are not amorphous) at 850 to 1150 ℃, the bonding between particles by fusion or sintering can be completely suppressed.
[ spherical crystalline silica particles ]
(roundness degree)
The spherical crystalline silica particles of the present invention have a circularity of 0.80 or more.
If the circularity is less than 0.80, the fluidity, dispersibility, and filling property are insufficient when used as silica particles or the like of a resin composite composition for a semiconductor sealing material, and abrasion of the sealing material to a manufacturing machine may be accelerated. The spherical amorphous silica particles obtained by melt blowing may have an average circularity of 0.80 or more. Since the temperature in the heat treatment step for crystallization is 850 to 1150 ℃, the circularity of the silica particles before and after the heat treatment is almost unchanged. Furthermore, if the melt-blowing method is used, particles having a high average circularity can be easily obtained. As a result, the method of the present invention can realize desired spherical crystalline silica particles having a high circularity. From the viewpoint of improving fluidity, dispersibility, filling property, or reducing abrasion of equipment, the higher the circularity is, the more preferable it is, the higher it may be 0.85 or more, and the more preferable it may be 0.90 or more. On the other hand, it may be difficult to set the circularity to 1.0, that is, to a perfect circle, so the upper limit of the circularity may be 0.99 or less or 0.97 or less.
The circularity is obtained by "the circumference of the circle corresponding to the projected area of the captured particle ÷ the circumference of the image of the captured particle", and the value closer to 1 represents the closer to a perfect sphere. The circularity of the present invention is obtained by a dynamic particle image analysis method. In the moving particle image analysis method, spherical crystalline silica particles are poured into a liquid to be photographed as a still image of the particles, and an image analysis is performed based on the obtained particle image to determine the circularity of the spherical crystalline silica particles. The average value of the plurality of circularities is defined as an average circularity. When the average circularity is measured by a dynamic particle image analysis method, an accurate average value cannot be obtained if the number of particles is too small. The number of particles is at least 100 or more, preferably 500 or more, and more preferably 1000 or more. In the present invention, a dynamic particle image analysis device "FPIA-3000" (manufactured by spectrorisco., ltd.) and about 100 particles are used. The circularity of spherical amorphous silica particles was determined in the same manner as described above.
(composition)
The spherical crystalline silica particles of the present invention contain 0.02 mass% or more and less than 0.40 mass% of lithium in terms of oxide and 0.004 mass% or more and less than 1.0 mass% of calcium in terms of oxide, based on the mass (100 mass%) of the silica particles. The lower limit of lithium is preferably 0.05% by mass, more preferably 0.10% by mass, and still more preferably 0.25% by mass. The upper limit of lithium is preferably less than 0.35% by mass, and more preferably less than 0.30% by mass. The lower limit of calcium is preferably 0.20% by mass, and more preferably 0.6% by mass. The upper limit of the amount of calcium is preferably 0.9% by mass, and more preferably 0.8% by mass. The lithium and calcium contents can be measured by atomic absorption spectrometry, ICP mass spectrometry (ICP-MS), for example. Specifically, measurement was carried out by ICP-MS (7700X, product of Agilent) in accordance with JIS-K0133. An aqueous solution in which silica particles were completely dissolved by hydrofluoric acid was used as a sample. Here, the content of the impurity element contained in the silica particles is defined as the content of the impurity element in the silica-dissolved solution. The standard curve may also use a reagent-only base solution. By performing a specific heat treatment in a composition containing lithium and calcium in the above-mentioned range, spherical crystalline silica particles having a high crystallization ratio and a substantially high quartz ratio and composed of a single phase can be obtained. Lithium and calcium are almost completely present in the form of oxides by heat treatment in a temperature range of 850 to 1150 ℃ for crystallization, and thereafter, react with silica to incorporate lithium or calcium into the silica structure, so that their contents are almost unchanged before and after heat treatment in the temperature range. When the lithium and calcium contents are changed before and after the heat treatment, the composition of the raw material may be appropriately adjusted in consideration of the degree of the change in order to achieve a predetermined lithium and calcium content in the finally obtained spherical crystalline silica particles.
(Properties of Crystal)
The spherical crystalline silica particles of the present invention contain a phase of crystalline silica, and the spherical crystalline silica particles have a proportion of the phase of crystalline silica of 40.0% or more and a proportion of quartz in the phase of crystalline silica of 80.0% or more by mass.
In the case where the silica particles obtained by the heat treatment are composed of amorphous and crystalline silica, the existence ratio of amorphous and crystalline silica (i.e., "crystallinity", which is referred to as such in the present specification), and the kind and ratio of crystalline silica can be obtained by XRD. In the XRD measurement, the ratio of the crystal phase can be calculated from the sum (Ic) of the integrated intensities of the crystalline peaks and the integrated intensity (Ia) of the amorphous halo portion by the following formula. More specifically, the ratio of the phase of the crystalline silica contained in the spherical crystalline silica particles can be determined.
X (crystal phase ratio) = Ic/(Ic + Ia). Times.100 (%)
In the present invention, XRD measurement is performed in a range of 2 Θ =10 ° to 90 °. The crystal phase ratio was determined from the sum of the peak intensities of the crystalline phases appearing in the 2 Θ measurement range and the integrated intensity of the halo portion due to the amorphous phase appearing in the vicinity of 2 Θ =22 °.
Further, the type and the ratio (mass%) of crystal phases such as cristobalite and quartz can be determined by quantitative analysis by X-ray diffraction. In the present invention, quantitative analysis by X-ray refraction was performed using an analytical method by the rietveld method, and quantitative analysis was performed without using a standard sample. In the present invention, an X-ray diffraction device "D2 PHASER" (manufactured by BRUKER CORPORATION) is used. Quantitative analysis of the crystal phase by the Rittwold method was carried out by using the crystal structure analysis software "TOPAS" (manufactured by BRUKER CORPORATION).
The spherical crystalline silica particles of the present invention preferably contain a phase of crystalline silica, and the spherical crystalline silica particles have a high crystallinity of 40.0% or more, that is, 40.0% or more, and a dielectric loss tangent significantly lower than that of amorphous silica. From the viewpoint of lowering the dielectric loss tangent, the higher the crystallinity may be, 70.0% or more, and more preferably 80.0% or more.
The spherical crystalline silica particles of the present invention contain a crystalline silica phase in which the proportion of quartz is high, 80.0 mass% or more, and which is substantially a single phase of quartz. Therefore, many properties such as thermal expansion coefficient and thermal conductivity of the spherical crystalline silica particles are substantially determined by the properties of quartz, that is, they do not change, and it is preferable to use them for the filler. From the above viewpoint, the higher the proportion of quartz is, the more preferable it is, it may be 85.0 mass% or more, and more preferably it may be 90.0 mass% or more.
(average particle diameter)
In one embodiment of the present invention, the spherical crystalline silica particles may have an average particle diameter (D50) of 3 to 100. Mu.m. When the average particle diameter is less than 3 μm, the particles are undesirably increased in cohesiveness and remarkably reduced in flowability. When the average particle size exceeds 100. Mu.m, voids tend to remain between particles, and it is difficult to improve the filling property, which is not preferable. The average particle diameter is more preferably in the range of 10 to 80 μm. The spherical amorphous silica particles before heat treatment hardly change in particle size before and after heat treatment in a temperature range of 850 to 1150 ℃.
The average particle diameter (D50) was measured by a laser diffraction/scattering particle size distribution measurement method, and a median particle diameter D50 of 50% in cumulative volume in a volume-based particle size distribution was determined. The laser diffraction/scattering particle size distribution measurement method is a method of irradiating a dispersion liquid in which spherical crystalline silica particles are dispersed with laser light to obtain a particle size distribution from an intensity distribution pattern of diffracted/scattered light emitted from the dispersion liquid. In the present invention, a laser diffraction/scattering particle size distribution measuring apparatus "CILAS920" (manufactured by Silas) was used. The average particle diameter of the spherical amorphous silica particles can also be determined in the same manner.
(example of use)
According to the present invention, a composite composition of spherical crystalline silica particles and a resin to be finally obtained can be produced, and a resin composite obtained by curing the resin composite composition can be further produced. The composition of the resin composite composition will be described below.
A resin composite composition such as a semiconductor sealing material (particularly a solid sealing material) or an interlayer insulating film can be obtained by using a paste composition containing spherical crystalline silica particles and a resin. Further, by curing these resin composite compositions, a resin composite such as a sealing material (cured body) or a substrate for a semiconductor package can be obtained.
When the resin composite composition is produced, for example, in addition to the spherical crystalline silica particles and the resin, a curing agent, a curing accelerator, a flame retardant, a silane coupling agent, and the like are added as necessary, and the mixture is compounded by a known method such as kneading. Then, the mixture is molded into a granular form, a film form, or the like according to the use.
Further, when the resin composite composition is cured to produce a resin composite, for example, the resin composite composition is heated and melted, subjected to shape processing according to the use, and completely cured by applying heat higher than that at the time of melting. In this case, a known method such as transfer molding can be used.
For example, in the case of manufacturing a semiconductor-related material such as a substrate for sealing or an interlayer insulating film, a known resin can be used as the resin used for the resin composite composition, but an epoxy resin is preferably used. The epoxy resin is not particularly limited, and for example: bisphenol a type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthalene type epoxy resin, phenoxy type epoxy resin, and the like. One of them may be used alone in 1 kind, or 2 or more kinds having different molecular weights may be used in combination. Among them, an epoxy resin having 2 or more epoxy groups in 1 molecule is preferable from the viewpoint of curability, heat resistance, and the like. Specifically, for example: examples of the epoxy resin include epoxy resins obtained by epoxidizing biphenyl type epoxy resins, phenol novolac type epoxy resins, o-cresol novolac type epoxy resins, products obtained by epoxidizing phenol and aldehyde novolac resins, glycidyl ether such as bisphenol a, bisphenol F and bisphenol S, glycidyl ester type epoxy resins obtained by reacting polybasic acid such as phthalic acid or dimer acid with epichlorohydrin, linear aliphatic epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, alkyl-modified polyfunctional epoxy resins, β -naphthol novolac type epoxy resins, 1, 6-dihydroxynaphthalene type epoxy resins, 2, 7-dihydroxynaphthalene type epoxy resins, dihydroxybiphenyl type epoxy resins, and epoxy resins introduced with halogen such as bromine for imparting flame retardancy. Among these epoxy resins having 2 or more epoxy groups in a single molecule, bisphenol a type epoxy resins are particularly preferred.
In addition, applications other than the composite material for a semiconductor sealing material are also applicable as a resin used for a resin composite composition such as a prepreg for a printed board and various engineering plastics, and a resin other than epoxy. Specifically, in addition to the epoxy resin, for example: polyamides such as silicone resins, phenol resins, melamine resins, urea resins, unsaturated polyesters, fluorine resins, polyimides, polyamideimides, and polyetherimides; polyesters such as polybutylene terephthalate and polyethylene terephthalate; polyphenylene sulfide, aromatic polyester, polysulfone, liquid crystal polymer, polyethersulfone, polycarbonate, maleimide-modified resin, ABS resin, AAS (acrylonitrile-butyl acrylate-styrene) resin, AES (acrylonitrile-EPDM rubber-styrene) resin.
As the curing agent used for the resin composite composition, a known curing agent may be used for curing the resin, and for example, a phenol-based curing agent may also be used. As the phenol-based curing agent, phenol novolac resin, alkylphenol novolac resin, polyvinyl phenol, or the like can be used alone, or 2 or more of them can be used in combination.
The equivalent ratio of the phenolic curing agent to the epoxy resin (phenolic hydroxyl group equivalent/epoxy group equivalent) is preferably 0.1 or more and less than 1.0. Accordingly, the unreacted phenol curing agent does not remain, and the moisture absorption heat resistance is improved.
The amount of the spherical crystalline silica particles of the present invention added to the resin composite composition is usually preferably from the viewpoint of heat resistance and thermal expansion coefficient, and is usually 70 mass% to 95 mass%, preferably 80 mass% to 95 mass%, more preferably 85 mass% to 95 mass%. The reason is that if the amount of silica powder blended is too small, it is difficult to obtain effects such as improvement in strength of the sealing material and suppression of thermal expansion, and conversely if it is too large, segregation due to aggregation of silica powder in the composite material is more likely to occur regardless of the surface treatment of the silica powder, and the viscosity of the composite material is too high, and therefore, it is difficult to put into practical use as a sealing material because of these problems.
As the silane coupling agent, a known coupling agent can be used, and it is preferable to have an epoxy functional group.
Examples
The present invention is illustrated by the following examples and comparative examples. The present invention is not limited to the following examples.
(examples 1 to 3)
Amorphous silica particles containing calcium are produced by a melt-blowing method. After mixing lithium carbonate particles with the spherical amorphous silica particles, an aluminum container was filled, and heat treatment was performed in an atmospheric atmosphere (atmospheric pressure) using SUPER-BURN (product of MOTOYAMA corporation). The amount of lithium carbonate added was 0.25 mass% in terms of oxide, and the amount of calcium contained in the amorphous silica particles was 0.004 mass% in terms of oxide, based on the total mass of the spherical amorphous silica particles and the mass of lithium converted to oxide. The temperature was raised to 900 ℃ (example 1), 1000 ℃ (example 2), and 1100 ℃ (example 3) at a temperature raising rate of 300 ℃/hr, and the mixture was held for 6 hours. Then, the mixture was cooled to room temperature at a cooling rate of approximately 100 ℃ per hour.
(examples 4 to 6)
Amorphous silica particles containing calcium were prepared by a melt-blowing method. The calcium content in the amorphous silica particles was set to 0.0040 mass%. Lithium carbonate was mixed in an amount of 0.10 mass% (example 4), 0.07 mass% (example 5), and 0.05 mass% (example 6) in terms of oxide, based on the total mass of the mass of spherical amorphous silica and the mass of lithium in terms of oxide. The temperature was raised to 930 deg.C (example 4), 1030 deg.C (example 5) and 1130 deg.C (example 6) at a rate of 300 deg.C and held for 6 hours. Then, the mixture was cooled to room temperature at a temperature increase rate of 100 ℃.
(examples 7 to 9)
Amorphous silica particles containing calcium were prepared by a melt-blowing method. The lithium carbonate particles were mixed by 0.25 mass% in terms of oxide and the calcium contained in the amorphous silica particles was mixed by 0.24 mass% in terms of oxide, based on the total mass of the spherical amorphous silica and the mass of lithium in terms of oxide. The temperature was raised to 900 ℃ (example 7), 1000 ℃ (example 8), and 1100 ℃ (example 9) at a temperature raising rate of 300 ℃/h, and the mixture was held for 6 hours. Except for this, the heat treatment was performed in the same manner as in example 1.
(example 10 to example 12)
Amorphous silica particles containing calcium were prepared by a melt-blowing method. The lithium carbonate particles were mixed by 0.25 mass% in terms of oxide and the calcium contained in the amorphous silica particles was 0.66 mass% in terms of oxide, based on the total mass of the spherical amorphous silica and the mass of lithium in terms of oxide. Then, the temperature was raised to 900 ℃ (example 10), 1000 ℃ (example 11), and 1100 ℃ (example 12) at a temperature raising rate of 300 ℃/hr, and the mixture was held for 6 hours. Then, the mixture was cooled to room temperature at a cooling rate of approximately 100 ℃ per hour.
(example 13, example 14)
Amorphous silica particles containing calcium are produced by a melt-blowing method. The lithium carbonate particles were mixed by 0.05 mass% in terms of oxide and the amorphous silica particles contained calcium by 0.66 mass% in terms of oxide, based on the total mass of the spherical amorphous silica particles and the mass of lithium in terms of oxide. Then, the temperature was raised to 925 ℃ in example 13 and to 1080 ℃ in example 14 at a temperature raising rate of 300 ℃/h. Then, heat treatment was performed in the same manner as in example 1 except that the temperature was maintained for 6 hours in example 13 and for 24 hours in example 14.
(examples 15 and 16)
Amorphous silica particles containing calcium were prepared by a melt-blowing method. The lithium carbonate particles were mixed in an amount of 0.10 mass% in terms of oxide (example 15) and 0.02 mass% in terms of oxide (example 16) based on the total mass of the spherical amorphous silica and the mass of lithium in terms of oxide, and the calcium contained in the amorphous silica particles was 0.66 mass% in terms of oxide. Then, the temperature was raised to 925 ℃ in example 15 and 950 ℃ in example 16 at a temperature raising rate of 300 ℃/min. And then held for 6 hours, except that heat treatment was performed in the same manner as in example 1.
(example 17 to example 20)
Amorphous silica particles are produced by a melt-blown process. Calcium hydroxide particles and lithium carbonate particles were mixed with the spherical amorphous silica particles, and the mixture was charged into an aluminum container and heat-treated in an atmosphere (atmospheric pressure) using SUPER-BURN (manufactured by MOTOYAMA corporation). The amount of calcium hydroxide mixed was 0.48 mass% in terms of oxide and the amount of lithium carbonate mixed was 0.04 mass% (example 17), 0.06 mass% (example 18), 0.08 mass% (example 19), 0.10 mass% (example 20) in terms of oxide, based on the total mass of the mass of spherical amorphous silica, the mass of calcium in terms of oxide, and the mass of lithium in terms of oxide. The temperature was raised to 925 ℃ at a temperature raising rate of 300 ℃/hr and held for 12 hours. Then, the mixture was cooled to room temperature at a cooling rate of approximately 100 ℃ per hour.
(example 21 and example 22)
Amorphous silica particles containing calcium and lithium were produced by a melt-blowing method. The spherical amorphous silica particles were packed in an aluminum container and heat-treated in an atmospheric atmosphere (atmospheric pressure) using SUPER-BURN (manufactured by MOTOYAMA corporation). The amorphous silica particles contained 0.82 mass% of calcium in terms of oxide and 0.08 mass% of lithium in terms of oxide. The temperature was raised to 950 ℃ and 1050 ℃ at a rate of 300 ℃/min (example 21) and held for 24 hours. Then, the mixture was cooled to room temperature at a cooling rate of approximately 100 ℃ per hour.
Amorphous silica particles containing lithium were produced by a melt-blowing method. After mixing calcium compound particles with the spherical amorphous silica particles, the spherical amorphous silica particles are filled in an aluminum container and heat-treated at 850 to 1150 ℃ in an atmospheric atmosphere (atmospheric pressure) using SUPER-BURN (manufactured by MOTOYAMA corporation).
Comparative example 1
Amorphous silica particles containing 0.004 mass% of calcium in terms of oxide were produced by a melt-blowing method. Heat treatment was performed in the same manner as in example 1 except that the spherical amorphous silica particles were not mixed with lithium carbonate particles, and then heated to 900 ℃ at a heating rate of 300 ℃/hr and held for 6 hours.
Comparative example 2
Amorphous silica particles containing calcium were prepared by a melt-blowing method. Heat treatment was performed in the same manner as in example 1 except that 0.25 mass% of lithium carbonate particles in terms of oxides and 0.004 mass% of calcium contained in amorphous silica particles in terms of oxides were mixed in terms of the total mass of spherical amorphous silica and lithium in terms of oxides, and then the temperature was raised to 1200 ℃.
Comparative examples 3 and 4
Amorphous silica particles containing calcium were prepared by a melt-blowing method. Heat treatment was performed in the same manner as in example 1 except that 0.25 mass% of lithium carbonate particles in terms of oxide and 0.24 mass% of calcium contained in amorphous silica particles in terms of oxide were mixed with respect to the total mass of the mass of spherical amorphous silica and the mass of lithium in terms of oxide, and then the temperature was raised to 1200 ℃ (comparative example 3) and 800 ℃ (comparative example 4) at a temperature raising rate of 300 ℃/h and held for 6 hours.
Comparative example 5
Amorphous silica particles containing calcium were prepared by a melt-blowing method. Heat treatment was performed in the same manner as in example 1 except that 0.25 mass% of lithium carbonate particles in terms of oxides and 0.0014 mass% of calcium contained in amorphous silica particles in terms of oxides were mixed in terms of oxides with respect to the total mass of spherical amorphous silica and lithium in terms of oxides, and then the temperature was raised to 900 ℃ at a temperature raising rate of 300 ℃/hr and held for 6 hours.
Comparative example 6
Amorphous silica particles containing calcium were prepared by a melt-blowing method. Heat treatment was performed in the same manner as in example 1 except that 0.01 mass% in terms of oxide of lithium carbonate particles and 0.66 mass% in terms of oxide of calcium contained in amorphous silica particles were mixed with respect to the total mass of the mass of spherical amorphous silica and the mass of lithium in terms of oxide, and then the temperature was raised to 925 ℃ at a temperature raising rate of 300 ℃/h and held for 6 hours.
Comparative example 7
Amorphous silica particles containing 0.66 mass% of calcium in terms of metal were produced by a melt-blown method. Heat treatment was performed in the same manner as in example 1 except that the spherical amorphous silica particles were not mixed with lithium carbonate particles, and then heated to 1100 ℃ at a heating rate of 300 ℃/hr and held for 6 hours.
The existence ratio of amorphous and crystalline silica in the silica particles obtained by the heat treatment, and the kind and ratio of crystalline silica were determined by XRD. In the present invention, an X-ray diffraction device "D2 PHASER" (manufactured by BRUKER CORPORATION) is used. Quantitative analysis of the crystal phase by the Ritvelder method was carried out by using the crystal structure analysis software "TOPAS" (manufactured by BRUKER CORPORATION).
The circularity is obtained by dynamic particle image analysis. In the present invention, a dynamic particle image analysis device "FPIA-3000" (manufactured by spectroris co., ltd.) is used.
The content of impurity elements such as lithium and calcium in the spherical silica particles of the present invention is measured by ICP mass spectrometry (ICP-MS). Specifically, measurement was carried out by ICP-MS (7700X, product of Agilent) in accordance with JIS-K0133. An aqueous solution in which silica particles were completely dissolved by hydrofluoric acid was used as a sample. Here, the content of the impurity element contained in the silica particles is defined as the content of the impurity element in the silica-dissolved solution. The standard curve uses a reagent-only base solution.
The average particle diameter (D50) of the spherical quartz particles was measured by a laser diffraction/scattering particle size distribution measuring method, and in the present invention, a laser diffraction/scattering particle size distribution measuring apparatus "CILAS920" (manufactured by Silas) was used.
The spherical crystalline silica particles obtained in the examples of the present invention each have a lithium content in the range of 0.02 mass% or more and less than 0.40 mass% in terms of oxide, and contain a crystalline silica phase, the spherical crystalline silica particles having a crystalline silica phase ratio of 40.0% or more and a crystalline silica phase ratio of 80 mass% or more. The spherical crystalline silica particles of the examples of the present invention had a circularity of 0.83 to 0.95.
The average particle diameter of spherical amorphous silica particles containing 0.004 mass% of calcium in terms of oxide is 35.1. Mu.m, whereas the average particle diameter of spherical crystalline silica particles of the present invention using the above raw material is 35.2 to 35.6. Mu.m.
In addition, the average particle diameter of the spherical amorphous silica particles containing 0.24 mass% of calcium is 33.8 μm, while the spherical crystalline silica particles of the present invention using the raw material are 33.3 to 33.9 μm.
In addition, spherical amorphous silica particles containing 0.66 mass% of calcium in terms of oxide were 41.1 μm, while spherical crystalline silica particles of the present invention using the above raw material were 40.9 to 41.5 μm.
In addition, when a mixed raw material powder obtained by mixing a calcium raw material containing 0.48 mass% of calcium in terms of oxide and a lithium raw material containing 0.04 to 0.10 mass of lithium in terms of oxide into amorphous silica particles is subjected to heat treatment, the average particle diameter of spherical amorphous silica particles is 32.3 μm, whereas the spherical crystalline silica particles of the present invention using the mixed raw material powder are 31.6 μm to 35.1 μm.
Further, the average particle diameter of spherical amorphous silica particles containing 0.82 mass% and 0.08 mass% of calcium and lithium in terms of oxide was 21.5 μm, while the spherical crystalline silica particles of the present invention using the above raw materials were 20.3 μm and 21.9 μm.
It is understood that when the lithium content is 0.25 mass% and the calcium content is higher than 0.004 mass% in terms of oxide, the ratio of the crystalline silica phase in the spherical crystalline silica particles is more than 40.0% as compared with comparative example 5 in examples 1 and 7. It is found that a synergistic effect of coexistence of calcium and lithium elements is exhibited to promote the progress of crystallization. Further, in comparative example 1, even when 0.004 mass% of calcium in terms of oxide was contained, crystallization could not proceed unless lithium was added. It is known that coexistence of lithium and calcium is necessary.
As is clear from examples 4 to 6 and examples 13 to 16, the lower limit of the amount of lithium added is 0.02 mass% as compared with comparative examples 6 and 7.
Comparing examples 1 to 3 with comparative example 2, and comparing examples 7 to 9 with comparative example 3, it is understood that the content of cristobalite increases when the heat treatment temperature is high, and the proportion of quartz in the phase of crystalline silica at 1200 ℃ is less than 80 mass%. Further, it is understood that, when comparing examples 7 to 9 with comparative example 4, crystallization does not proceed at a heat treatment temperature of 800 ℃, and the ratio of crystalline silica phase in the spherical crystalline silica particles is less than 40%. The heat treatment temperature is preferably 850 ℃ to 1150 ℃. More preferably the temperature is in the range 875 ℃ to 1100 ℃.
In comparison with comparative example 7, in example 12, even when 0.66 mass% or more of calcium was contained in terms of oxide, the ratio of the crystalline silica phase in the spherical crystalline silica particles was 11.4% and less than 40.0% when no lithium was added. When lithium is 0.02 mass% or more in terms of oxide, the proportion of crystalline silica phase in the spherical crystalline silica particles exceeds 40%, and the proportion of quartz in the crystalline silica phase exceeds 80 mass%. This shows that the high crystallization rate of quartz is a synergistic effect due to the coexistence of calcium and lithium. Even if the content of lithium or calcium is increased (0.02 mass% or more in terms of lithium oxide, 0.004 mass% or more in terms of calcium oxide), there is no problem in the crystallinity and the quartification degree, the proportion of the phase of crystalline silica in the spherical crystalline silica particles is 40.0% or more, and the proportion of quartz in the phase of crystalline silica exceeds 80 mass%.
The spherical crystalline silica particles of examples and comparative examples to which the present invention was applied had a zinc content of less than 1.0ppm in terms of metal, a total of alkali metals (K and Na) other than lithium was 24 to 36ppm in terms of metal, a total of alkaline earth metals (Mg + Ba) other than calcium was 1.8 to 42ppm, and metallic aluminum was 90 to 4552ppm. These metal impurities other than lithium and calcium may be contained in the silica within a range not affecting crystallization.
TABLE 1
TABLE 2
TABLE 3
TABLE 4
Possibility of industrial utilization
The spherical crystalline silica particles of the present invention can be used for other applications as well, not only for semiconductor sealing materials. Specifically, the resin composition can be used as a prepreg for a printed board, various engineering plastics, or the like.
Claims (9)
1. Spherical crystalline silica particles having a circularity of 0.80 or more, containing 0.02 mass% or more and less than 0.40 mass% of lithium in terms of oxide, containing 0.004 mass% or more and less than 1.0 mass% of calcium in terms of oxide, and containing a crystalline silica phase, wherein the proportion of the crystalline silica phase in the spherical crystalline silica particles is 40.0% or more, and the proportion of quartz in the crystalline silica phase is 80.0 mass% or more.
2. The spherical crystalline silica particles according to claim 1, wherein the proportion of the crystalline silica phase is 70.0% or more, and the proportion of quartz in the crystalline silica phase is 85.0% or more by mass.
3. The spherical crystalline silica particles according to claim 2, wherein the proportion of the phase of the crystalline silica is 80.0% or more, and the proportion of quartz in the phase of the crystalline silica is 90.0% or more by mass.
4. Spherical crystalline silica particles according to any one of claims 1 to 3, having an average particle diameter D50 of from 3 to 100 μm.
5. The method for producing spherical crystalline silica particles according to any one of claims 1 to 4, which comprises:
a mixed raw material powder obtained by mixing a calcium raw material and a lithium raw material into spherical amorphous silica particles having a circularity of 0.80 or more is heat-treated at 850 to 1150 ℃.
6. The process for producing spherical crystalline silica particles according to any one of claims 1 to 4, which comprises:
a mixed raw material powder obtained by mixing a lithium raw material with spherical amorphous silica particles having a circularity of 0.80 or more and containing a calcium component is heat-treated at 850 to 1150 ℃.
7. The process for producing spherical crystalline silica particles according to any one of claims 1 to 4, which comprises:
a mixed raw material powder obtained by mixing a calcium raw material with spherical amorphous silica particles having a circularity of 0.80 or more and containing a lithium component is heat-treated at 850 to 1150 ℃.
8. The process for producing spherical crystalline silica particles according to any one of claims 1 to 4, which comprises:
spherical amorphous silica particles having a circularity of 0.80 or more and containing a calcium component and a lithium component are heat-treated at 850 to 1150 ℃.
9. Process for the manufacture of spherical crystalline silica particles according to any one of claims 5 to 8, said heat treatment being carried out at a temperature of from 875 ℃ to 1110 ℃.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102482137A (en) * | 2009-10-14 | 2012-05-30 | 信越石英株式会社 | Silica powder, silica container, and method for producing the silica powder and container |
| CN103114333A (en) * | 2012-12-18 | 2013-05-22 | 常州英中纳米科技有限公司 | Preparation method of monocrystalline spherical silicon dioxide particles |
| CN109155246A (en) * | 2016-04-22 | 2019-01-04 | 日挥触媒化成株式会社 | Silica-based composite particles dispersion liquid and its manufacturing method |
| JP2019064893A (en) * | 2017-10-04 | 2019-04-25 | 日鉄ケミカル＆マテリアル株式会社 | Spherical crystalline silica particle and method for producing the same |
| CN110636989A (en) * | 2017-04-05 | 2019-12-31 | 日铁化学材料株式会社 | Spherical crystalline silica particles and method for producing same |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2002020111A (en) | 2000-06-29 | 2002-01-23 | Kyocera Corp | Porous powder and method for producing the same |
| JP6347653B2 (en) * | 2014-04-21 | 2018-06-27 | 新日鉄住金マテリアルズ株式会社 | Method for producing spherical particles |
| CN106660813B (en) * | 2014-08-25 | 2019-06-11 | 新日铁住金高新材料株式会社 | Spheroidal cementite silicon dioxide granule and its manufacturing method |
| JP7112179B2 (en) * | 2016-10-19 | 2022-08-03 | 日鉄ケミカル＆マテリアル株式会社 | Spherical siliceous powder for semiconductor encapsulant and method for producing the same |
| JP6934344B2 (en) * | 2017-07-18 | 2021-09-15 | デンカ株式会社 | Powder for spherical silica filler and its manufacturing method |
-
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- 2021-05-20 WO PCT/JP2021/019250 patent/WO2021235530A1/en active Application Filing
- 2021-05-20 TW TW110118341A patent/TW202200499A/en unknown
- 2021-05-20 JP JP2022524543A patent/JPWO2021235530A1/ja active Pending
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102482137A (en) * | 2009-10-14 | 2012-05-30 | 信越石英株式会社 | Silica powder, silica container, and method for producing the silica powder and container |
| CN103114333A (en) * | 2012-12-18 | 2013-05-22 | 常州英中纳米科技有限公司 | Preparation method of monocrystalline spherical silicon dioxide particles |
| CN109155246A (en) * | 2016-04-22 | 2019-01-04 | 日挥触媒化成株式会社 | Silica-based composite particles dispersion liquid and its manufacturing method |
| CN110636989A (en) * | 2017-04-05 | 2019-12-31 | 日铁化学材料株式会社 | Spherical crystalline silica particles and method for producing same |
| US20200148544A1 (en) * | 2017-04-05 | 2020-05-14 | Nippon Steel Chemical & Material Co., Ltd. | Spherical crystalline silica particles and method for producing same |
| JP2019064893A (en) * | 2017-10-04 | 2019-04-25 | 日鉄ケミカル＆マテリアル株式会社 | Spherical crystalline silica particle and method for producing the same |
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| TW202200499A (en) | 2022-01-01 |
| WO2021235530A1 (en) | 2021-11-25 |
| JPWO2021235530A1 (en) | 2021-11-25 |
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