JP2017199765A - High-voltage protection particle, method of manufacturing the same, and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-voltage protection particle that is useful for manufacturing a resin cured product that exhibits a larger value of a non linear coefficient compared with a conventional art, and to provide a method of manufacturing the high-voltage protection particle, and a semiconductor device that uses the high-voltage protection particle.SOLUTION: A high-voltage protection particle 110 used for manufacturing a resin cured product whose voltage-current characteristics do not follow with Ohm's law and that exhibits nonlinearity, includes: a semiconductor ceramic particle 100 that has a grain boundary part, and a plurality of crystal parts separated by the grain boundary part; and a resin layer 320 that coats a surface of the semiconductor ceramic particle 100.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a high voltage protective particle, a method for manufacturing the high voltage protective particle, and a semiconductor device.

In recent years, with the progress of technology capable of high-density mounting, electronic components have been reduced in size and weight. Therefore, the circuit mounted in the electronic component tends to be densified.
Here, in the case of an electronic component on which a high-density circuit is mounted, application of an overvoltage such as static electricity to the electronic component causes malfunction of the electronic component, or damage to the electronic component. There is a tendency for the possibility of inconveniences such as to increase.

  In view of such circumstances, several reports have been made on techniques for protecting electronic elements mounted in circuits mounted in electronic components from overvoltage such as static electricity (Patent Documents 1 to 3). etc).

  Patent Documents 1 to 3 describe resin materials used for producing a cured resin that can exhibit a varistor function that seals and covers the entire external terminal of the electronic component body. Patent Documents 1 to 3 include a resin composition containing, as such a resin material, semiconductor ceramic particles that exhibit good non-linearity (varistor characteristics) in which voltage-current characteristics do not follow Ohm's law as fillers. Have been described.

Japanese Patent Laid-Open No. 06-244001 Japanese Patent Laid-Open No. 06-244002 Japanese Patent Laid-Open No. 06-244003

  However, when the present inventors produce a semiconductor device provided with a sealing material formed of a conventional resin composition containing semiconductor ceramic particles as a filler, it is included in the resin composition at the time of production. It has been found that there is a possibility that the semiconductor ceramic particles that are present may be partially damaged. Specifically, the present inventors have the possibility that the varistor characteristics may not be sufficiently developed as a result in a semiconductor device including a sealing material formed of a conventional resin composition containing semiconductor ceramic particles as a filler. Found that there is.

  Also, in recent years, from the viewpoint of improving durability reliability against overvoltage of electronic components, the technical level required for the varistor characteristics developed by members used to protect the electronic components from the overvoltage such as static electricity is increasing. It's getting higher.

  Therefore, the present invention uses a high-voltage protective particle useful for producing a cured resin having a larger nonlinear coefficient than conventional ones, a method for producing such a high-voltage protective particle, and the high-voltage protective particle. A semiconductor device was provided.

According to the present invention, high-voltage protective particles used for producing a cured resin that exhibits non-linearity in which voltage-current characteristics do not follow Ohm's law,
Semiconductor ceramic particles having a grain boundary part and a plurality of crystal parts separated by the grain boundary part;
A resin layer covering the surface of the semiconductor ceramic particles;
High voltage protective particles are provided.

Furthermore, according to the present invention, there is provided a method for producing high-voltage protective particles used for producing a resin cured product exhibiting nonlinearity in which voltage-current characteristics do not follow Ohm's law,
Preparing a semiconductor ceramic particle having a grain boundary part and a plurality of crystal parts separated by the grain boundary part;
Forming a resin layer covering the surface of the semiconductor ceramic particles;
A method for producing high voltage protective particles having the following is provided:

Furthermore, according to the present invention, a substrate;
A semiconductor element mounted on the substrate;
A sealing material that is made of a cured resin obtained by curing a material containing the high-voltage protective particles, and seals the semiconductor element;
A semiconductor device is provided.

  According to the present invention, a high-voltage protective particle useful for producing a cured resin having a large nonlinear coefficient as compared with the prior art, a method for producing the high-voltage protective particle, and the high-voltage protective particle are used. A semiconductor device can be provided.

It is sectional drawing of the high voltage protective particle which concerns on this embodiment. It is an expanded sectional view of the semiconductor ceramic particle concerning this embodiment. It is sectional drawing which shows an example of the semiconductor device which concerns on this embodiment. It is sectional drawing which shows an example of the semiconductor device which concerns on this embodiment. 3 is a diagram showing an SEM image of the cross-sectional shape of the particles of Example 1. FIG. 3 is a diagram showing an SEM image of the appearance shape (surface shape) of particles in Example 1. FIG. It is a figure for demonstrating the method of calculating a non-linear coefficient and a varistor voltage from the measurement result of an electric current value.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

<< High-voltage protective particles >>
FIG. 1 is a cross-sectional view of the high voltage protective particles according to the present embodiment.
The high voltage protective particles 110 according to the present embodiment are used for producing a cured resin that exhibits non-linearity in which voltage-current characteristics do not follow Ohm's law. As shown in FIG. 1, the high-voltage protective particle 110 covers the surface of the semiconductor ceramic particle 100 and the semiconductor ceramic particle 100 having a grain boundary part and a plurality of crystal parts separated by the grain boundary part. The resin layer 320 to be included.

  Here, the non-linearity (varistor characteristic) in which the voltage-current characteristic does not follow Ohm's law, which is indicated by the cured resin produced using the high-voltage protective particle 110 according to the present embodiment, depends on the applied voltage. A characteristic in which the resistance value varies nonlinearly. Specifically, the cured resin produced using the high-voltage protective particles 110 according to the present embodiment has an electrical insulation exhibiting a high resistance when a voltage lower than a breakdown voltage called a pre-breakdown region is applied. When a voltage higher than a breakdown voltage called a breakdown region is applied, it has conductivity showing extremely low resistance. In addition, the voltage which the characteristic which the resin hardened | cured material which concerns on this embodiment shows is converted from insulation to electroconductivity, or the voltage converted from electroconductivity to insulation is hereafter called a varistor voltage.

  As described above, the high-voltage protective particle 110 according to the present embodiment includes the semiconductor ceramic particle 100 and the resin layer 320 formed so as to cover the surface of the semiconductor ceramic particle 100 (see FIG. 1). . According to the high-voltage protective particles 110, it is possible to produce a cured resin having a higher nonlinear coefficient than conventional ones with a high yield.

  In the high voltage protective particle 110 according to the present embodiment, the resin layer 320 may be in a semi-cured state (B stage). In addition, the resin layer 320 may be in a dry state made of a resin mixture in which various solid raw material components are mixed without melting, including a thermosetting resin in a state before the curing reaction proceeds.

In the present embodiment, the resin layer 320 is formed of an aggregate of resin fine particles including a thermosetting resin from the viewpoint of producing a sealing material that exhibits good varistor characteristics with a high yield. preferable. That is, it is preferable that the resin layer 320 included in the high-voltage protection particle 110 according to the present embodiment is made of an aggregate of resin fine particles including a thermosetting resin.
When the resin layer 320 according to the present embodiment is formed of an aggregate of resin fine particles containing a thermosetting resin, the plurality of resin fine particles constituting the aggregate overlap each other and are compressed and integrated. Also good. In other words, when the resin layer 320 according to the present embodiment is formed of an aggregate of resin fine particles containing a thermosetting resin, a part of the aggregate may be plastically deformed.

  Here, when the resin layer 320 is formed of an aggregate of resin fine particles containing a thermosetting resin, it can be said that the high voltage protective particles 110 are formed by combining particles of different powders. In that case, the shape of the high-voltage protective particles 110 is preferably spherical from the viewpoint of improving handling properties and dispersibility. The spherical shape described above is not limited to a true sphere, but includes an elliptic rotating body and a rounded shape of an aggregate of the resin fine particles. Further, the surface may be uneven as long as it is rounded as a whole.

  In the high voltage protective particle 110 according to the present embodiment, the resin layer 320 described above preferably covers the entire outer peripheral surface of the semiconductor ceramic particle 100 from the viewpoint of improving the durability of the particle. However, the coverage is not particularly limited, and the resin layer 320 may cover only a part of the semiconductor ceramic particle 100.

Here, the analysis of the external structure and the cross-sectional structure of the high-voltage protective particle 110 according to the present embodiment can be performed by a scanning electron microscope, Raman spectroscopy, or the like.
For example, the analysis of the cross-sectional structure of the high-voltage protection particle 110 can be performed by the following method. First, using a cross section polisher (SM-09010, manufactured by JEOL Ltd.), the high voltage protective particles 110 are cut to expose the cross section. Then, the cross-sectional structure of the exposed high voltage protective particles 110 is analyzed using, for example, a scanning electron microscope (JSM-7401F, manufactured by JEOL Ltd.).

  Hereinafter, the configuration of the high-voltage protection particle 110 will be described by taking as an example the case where the resin layer 320 according to the present embodiment is formed of an aggregate of resin fine particles including a thermosetting resin.

  When the resin layer 320 according to the present embodiment is formed of an aggregate of resin fine particles including a thermosetting resin, some of the high voltage protection particles 110 are adhered to each other when the high voltage protection particles 110 are used. Thus, it is possible to suppress the occurrence of a factor causing molding defects such as a lump or a state where it is likely to become a lump.

  In the resin layer 320 in the high voltage protection particle 110 according to the present embodiment, when the resin fine particles are densely aggregated, the resin fine particles are integrated with each other, and the interface may not always be clearly observed. In this case, the resin layer 320 is observed in a circular shape along the outer periphery of the semiconductor ceramic particle 100 in the cross-sectional image of the high-voltage protection particle 110 by an electron microscope, so that the resin fine particle is in the radial direction of the semiconductor ceramic particle 100. It can be understood that they are aggregated so as to be laminated.

  The average particle diameter d50 of the high voltage protective particles 110 according to the present embodiment is preferably 5 μm or more and 220 μm or less, more preferably 5 μm or more and 150 μm or less, from the viewpoint of improving the handleability and dispersibility. More preferably, they are 10 micrometers or more and 80 micrometers or less.

  In addition, the average particle diameter d50 of the resin fine particles constituting the resin layer 320 according to the present embodiment is preferably 0.01 μm or more and 150 μm or less from the viewpoint of improving durability and manufacturing stability of the high voltage protection particles 110. More preferably, it is 0.1 μm or more and 50 μm or less, and further preferably 1 μm or more and 30 μm or less.

  Further, the upper limit value of the average particle diameter d50 of the resin fine particles constituting the resin layer 320 according to the present embodiment is preferably a semiconductor which will be described later, from the viewpoint of improving the durability and manufacturing stability of the high voltage protective particles 110. The average particle diameter d50 or less of the ceramic particles 100, more preferably 1/2 or less of the average particle diameter d50 of the semiconductor ceramic particles 100, and more preferably 3/10 of the average particle diameter d50 of the semiconductor ceramic particles 100. It is as follows. The lower limit value of the average particle diameter d50 of the resin fine particles is preferably 1/100 or more of the average particle diameter d50 of the semiconductor ceramic particles 100 from the viewpoint of improving the durability and manufacturing stability of the high-voltage protective particles 110. More preferably, it is 1/50 or more, and more preferably 1/30 or more.

Here, in this specification, the average particle diameter of each particle specifically refers to an average particle diameter d50 (median diameter) measured by the following method.
Median diameter: Measured by a wet method using a laser diffraction / scattering particle size distribution measuring apparatus (LA-950V2 manufactured by Horiba, Ltd.) using analysis based on Franhofer diffraction theory and Mie's scattering theory. When the particle size is divided into two, the median diameter is the diameter where the large side and the small side are equivalent. In the wet method, a small amount (about one earpick) of measurement sample is added to 50 mL of pure water, and then a surfactant is added, followed by treatment in an ultrasonic bath for 3 minutes, and a solution in which the sample is dispersed is used. .

  Further, in the high voltage protective particle 110 according to the present embodiment, the content of the resin layer 320 is such that the sealing material formed using the high voltage protective particle 110 is excellent in mechanical strength and surely exhibits varistor characteristics. From the viewpoint of making it, it is preferably 5% by mass or more and 40% by mass or less, and more preferably 7% by mass or more and 35% by mass or less, with respect to the total amount of the high voltage protective particles 110.

  In this embodiment, the high-voltage viscosity of the high-voltage protective particles 110 when measured at a measurement temperature of 175 ° C. and a load of 10 kg using a flow characteristic evaluation apparatus is preferably 10 Pa · s or more and 2000 Pa · s or less. More preferably, it is 12 Pa · s or more and 1500 Pa · s or less. By doing so, since the moldability of the high voltage protection particles 110 can be improved, it is possible to suppress the generation of voids inside the cured resin formed using the high voltage protection particles 110. Therefore, as a result, it is possible to manufacture a semiconductor device excellent in durability reliability in which the value of the nonlinear coefficient is larger than that of the conventional one.

  In the present embodiment, the spiral flow of the high voltage protective particles 110 is preferably 5 cm or more, more preferably 6 cm or more, and further preferably 8 cm or more. By doing so, it is possible to improve the resin filling property when the sealing material is formed using the high voltage protective particles 110. On the other hand, the upper limit value of the spiral flow of the high voltage protective particles 110 may be, for example, 200 cm or less, 150 cm or less, or 120 cm or less.

  Hereinafter, the components of the high voltage protection particle 110 according to the present embodiment will be described in detail.

  First, the high voltage protective particles 110 according to the present embodiment employ a configuration including the semiconductor ceramic particles 100 as described above. Thereby, the structure (resin cured product) produced using the high voltage protective particles 110 can exhibit the above-described varistor characteristics.

FIG. 2 is an enlarged cross-sectional view of the semiconductor ceramic particle 100 according to the present embodiment.
As shown in FIG. 2, the semiconductor ceramic particle 100 according to the present embodiment is a particle having a grain boundary part 20 and a plurality of crystal parts 10 separated by the grain boundary part 20. In other words, in the semiconductor ceramic particle 100 according to the present embodiment, a plurality of crystals composed of the grain boundary part 20 and two or more crystal parts 10 arranged so as to be separated from each other via the grain boundary part 20 are aggregated. It can be said that it is a particle. When a voltage lower than the varistor voltage is applied to the particle, the semiconductor ceramic particle 100 does not pass current because the grain boundary portion 20 acts as a resistance, but a voltage higher than the varistor voltage is applied. In some cases, the particle has a characteristic that a tunnel effect occurs and current is passed as shown by an arrow in FIG.

The average particle diameter d50 of the semiconductor ceramic particles 100 is preferably 0.01 μm or more and 150 μm or less, more preferably 0.1 μm or more and 120 μm or less, and further preferably 1 μm or more and 90 μm or less. By doing so, it becomes possible to develop good varistor characteristics without depending on the shape of the structure (cured resin) formed using the high voltage protective particles 110 including the semiconductor ceramic particles 100. The semiconductor ceramic particles 100 are preferably spherical particles. Thereby, the varistor voltage can be easily controlled.
In addition, when the semiconductor ceramic particle 100 is not spherical, the value of the average particle diameter d50 of the semiconductor ceramic particle 100 in the present embodiment may be a value approximated to a true sphere.

  In the semiconductor ceramic particle 100, the crystal part 10 preferably includes one or more components selected from the group consisting of zinc oxide, silicon carbide, strontium titanate, and barium titanate. When the crystal part 10 is formed of the above-described material, it is possible to improve the nonlinear coefficient and energy tolerance of the semiconductor ceramic particle 100 itself, and to suppress high voltage / high frequency noise. Among these, a material containing zinc oxide as a main component is preferable from the viewpoint of improving the non-linear coefficient and energy resistance of the high voltage protective particles 110. Since a material containing silicon carbide as a main component has a high dielectric breakdown voltage, it is suitable when the varistor voltage is set to a high voltage. A material containing strontium titanate as a main component is preferable in terms of absorption and suppression of high voltage / high frequency noise.

  In the semiconductor ceramic particle 100, the grain boundary portion 20 is selected from the group consisting of bismuth, praseodymium, antimony, manganese, cobalt and nickel, and compounds thereof from the viewpoint of improving the non-linearity of the high voltage protective particle 110. Preferably it contains more than one component. Especially, the grain boundary part 20 contains 1 or more types selected from the group which consists of bismuth, praseodymium, and these compounds from a viewpoint which makes the nonlinearity of the high voltage protective particle 110 still more favorable. preferable. Examples of these compounds include oxides, nitrides, organic compounds, and other inorganic compounds. From the viewpoint of improving the varistor characteristics exhibited by the high voltage protective particles 110, the oxides. It is preferable that

  Next, a resin material constituting the resin layer 320 in the high voltage protective particle 110 according to the present embodiment (hereinafter also referred to as the present resin material) will be described.

  From the viewpoint of using the high voltage protective particles 110 according to the present embodiment as a material for forming the encapsulant, the present resin material is intended to impart excellent electrical insulation and heat resistance to the encapsulant. It is preferable that it contains a thermosetting resin. Examples of such thermosetting resins include phenol novolak resins, cresol novolak resins, bisphenol A type novolak resins, triazine skeleton-containing phenol novolak resins and the like; unmodified resole phenol resins, tung oil, linseed oil, walnut oil, and the like Phenol resin such as resol type phenol resin such as oil-modified resol phenol resin modified with bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol M type epoxy resin, bisphenol Bisphenol type epoxy resins such as P type epoxy resin and bisphenol Z type epoxy resin; phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphtho Novolak type epoxy resins such as lenovolac type epoxy resin; biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, arylalkylene type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, stilbene type epoxy resin, hydroquinone type epoxy resin, phenoxy type Epoxy resin, dicyclopentadiene type epoxy resin, phenol aralkyl type epoxy resin, trifunctional type epoxy resin, heterocyclic ring containing epoxy resin, modified phenol type epoxy resin, norbornene type epoxy resin, adamantane type epoxy resin, fluorene type epoxy resin, etc. Epoxy resin; resin having triazine ring such as urea (urea) resin, melamine resin; unsaturated polyester resin; maleimide resin such as bismaleimide compound; Resin resin; diallyl phthalate resin; silicone resin; benzoxazine resin; polyimide resin; polyamideimide resin; benzocyclobutene resin, novolac type cyanate resin, bisphenol A type cyanate resin, bisphenol E type cyanate resin, tetramethylbisphenol F type cyanate resin And cyanate ester resins such as bisphenol-type cyanate resins. These may be used alone or in combination of two or more. Especially, it is preferable that this resin material contains 1 or more types selected from the group which consists of an epoxy resin, a phenol resin, and a maleimide resin from a viewpoint which makes the heat resistance and adhesiveness of a sealing material more excellent. .

  When using an epoxy resin as the thermosetting resin, specific examples of such an epoxy resin include monomers, oligomers, and polymers generally having two or more epoxy groups in one molecule regardless of the molecular weight and molecular structure. It is possible. Specific examples of such epoxy resins include biphenyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, stilbene type epoxy resins, hydroquinone type epoxy resins and the like; cresol novolac type epoxy resins, Novolak type epoxy resins such as phenol novolac type epoxy resin and naphthol novolak type epoxy resin; Phenol aralkyl type epoxy resins such as phenylene skeleton-containing phenol aralkyl type epoxy resin, biphenylene skeleton containing phenol aralkyl type epoxy resin, phenylene skeleton containing naphthol aralkyl type epoxy resin Resin; Trifunctional epoxy resin such as triphenolmethane type epoxy resin and alkyl-modified triphenolmethane type epoxy resin; Diene modified phenol type epoxy resins, modified phenol type epoxy resins such as terpene-modified phenol type epoxy resins; heterocycle-containing epoxy resins such as triazine nucleus-containing epoxy resins. These may be used alone or in combination of two or more.

  When a phenol resin is used as the thermosetting resin, specific examples of the phenol resin include novolak phenol resins such as phenol novolak resin, cresol novolak resin, bisphenol A type novolak resin, methylol type resole resin, dimethylene ether type. Examples include resol type phenol resins such as oil-modified resol phenol resins modified with resole resin, tung oil, linseed oil, walnut oil, and the like. These may be used alone or in combination of two or more.

  The content of the thermosetting resin relative to the total amount of the resin material is preferably 5% by mass to 80% by mass, more preferably 5% by mass to 60% by mass, and further preferably 10% by mass to 55% by mass. % Or less. By making content of a thermosetting resin more than the said lower limit, it can suppress that the fluidity | liquidity of this resin material falls. Further, by setting the content of the thermosetting resin to the upper limit value or less, the resin cured product produced using the high voltage protective particles 110 is exhibited while suppressing the heat dissipation of the resin material from being lowered. It is also possible to suppress the deterioration of the varistor characteristics.

  The resin material may contain a curing agent. Such a curing agent only needs to react with the thermosetting resin and be cured. Here, as a specific example of the curing agent that can be used when an epoxy resin is used as the thermosetting resin, a linear aliphatic group having 2 to 20 carbon atoms such as ethylenediamine, trimethylenediamine, tetramethylenediamine, and hexamethylenediamine. Diamine, metaphenylenediamine, paraphenylenediamine, paraxylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylsulfone, 4, Amino such as 4'-diaminodicyclohexane, bis (4-aminophenyl) phenylmethane, 1,5-diaminonaphthalene, metaxylenediamine, paraxylenediamine, 1,1-bis (4-aminophenyl) cyclohexane, dicyanodiamide Aniline Resol type phenol resins such as resole resin and dimethyl ether resole resin; Novolak type phenol resins such as phenol novolak resin, cresol novolak resin, tert-butylphenol novolak resin, nonylphenol novolak resin; phenylene skeleton containing phenol aralkyl resin, biphenylene skeleton containing phenol aralkyl resin Phenol aralkyl resins such as phenylene skeleton-containing naphthol aralkyl type phenol resins; phenol resins having a condensed polycyclic structure such as naphthalene skeleton and anthracene skeleton; polyoxystyrenes such as polyparaoxystyrene; hexahydrophthalic anhydride (HHPA), methyl Alicyclic acid anhydrides such as tetrahydrophthalic anhydride (MTHPA), trimellitic anhydride (TMA), pyroanhydride Acid anhydrides including aromatic acid anhydrides such as merit acid (PMDA) and benzophenone tetracarboxylic acid (BTDA); Polymercaptan compounds such as polysulfide, thioester and thioether; Isocyanate compounds such as isocyanate prepolymer and blocked isocyanate An organic acid such as a carboxylic acid-containing polyester resin. These may be used alone or in combination of two or more. Among them, from the viewpoint of improving the moisture resistance and reliability of the structure, a compound having at least two phenolic hydroxyl groups in one molecule is preferable. Specific examples thereof include phenol novolak resin, cresol novolak resin, and tert-butylphenol novolak. Resin, novolak type phenol resin such as nonylphenol novolac resin; resol type phenol resin; polyoxystyrene such as polyparaoxystyrene; phenylene skeleton-containing phenol aralkyl resin, biphenylene skeleton-containing phenol aralkyl resin, phenylene skeleton-containing naphthol aralkyl type phenol resin, etc. Can be mentioned.

  The content of the curing agent with respect to the total amount of the resin material is preferably 0.8% by mass or more and 50% by mass or less, and more preferably 1.5% by mass or more and 45% by mass or less. By setting the content of the curing agent relative to the total amount of the resin material within the above numerical range, good curability can be obtained while exhibiting good fluidity.

The resin material may contain a curing accelerator.
The curing accelerator that can be used when an epoxy resin is used as the thermosetting resin may be any accelerator that promotes the curing reaction between a functional group such as an epoxy group and the curing agent. Diazabicycloalkenes such as diazabicyclo [5.4.0] undecene-7 and derivatives thereof; amine compounds such as tributylamine and benzyldimethylamine; imidazole compounds such as 2-methylimidazole; triphenylphosphine and methyldiphenylphosphine Organic phosphines such as tetraphenylphosphonium / tetraphenylborate, tetraphenylphosphonium / tetrabenzoic acid borate, tetraphenylphosphonium / tetranaphthoic acid borate, tetraphenylphosphonium / tetranaphthoyloxyborate, tetraphenyl Ruhosuhoniumu Tetra naphthyl Oki Chevrolet preparative like tetra-substituted phosphonium tetra-substituted borate; triphenylphosphine was adduct of benzoquinone, and the like. These may be used alone or in combination of two or more.

  The content of the curing accelerator with respect to the total amount of the resin material is preferably 1% by mass or more and 8% by mass or less, and more preferably 2% by mass or more and 7% by mass or less. By setting the content of the curing accelerator to the total amount of the resin material within the above numerical range, sufficient curability can be obtained while exhibiting sufficient fluidity.

  In addition to the various components described above, the resin material may include a coupling agent such as γ-glycidoxypropyltrimethoxysilane; a colorant such as carbon black; a montanic acid ester wax; Release agents such as natural wax, synthetic wax, higher fatty acid or metal salts thereof, paraffin and polyethylene oxide; low stress agent such as silicone oil and silicone rubber; ion scavenger such as hydrotalcite; flame retardant such as aluminum hydroxide Various additives such as antioxidants can be blended.

  Next, a method for manufacturing the high voltage protective particles 110 according to this embodiment will be described.

The manufacturing method of the high-voltage protection particle 110 according to the present embodiment includes a step of preparing a semiconductor ceramic particle 100 having a grain boundary part and a plurality of crystal parts separated by the grain boundary part; Forming a resin layer covering the surface.
And the manufacturing method of the high voltage protection particle 110 which concerns on this embodiment is various raw material components containing the thermosetting resin used in order to form the semiconductor ceramic particle 100 and the resin layer 320 as a process of forming the said resin layer. It is preferable that the method includes a step of forming a resin layer 320 that covers the surface of the semiconductor ceramic particle 100 by mechanically combining the mixture.
Hereinafter, an example of the manufacturing method of the high voltage protective particles 110 according to the present embodiment will be described in detail.

  First, the semiconductor ceramic particles 100 and the raw material of the resin layer 320 to be coated on the surface of the semiconductor ceramic particles 100 are prepared. As a raw material of the resin layer 320, a pulverized product obtained by pulverizing a resin composition obtained by kneading various solid raw material components including a thermosetting resin may be used, or a thermosetting resin may be used. You may use the pulverized material obtained by grind | pulverizing and mixing the various solid raw material components to contain. The pulverization of the above-described resin composition or various solid raw material components can be carried out using a known pulverizer such as a jet mill. The shape of the pulverized product may be powdery, granular, crushed, substantially spherical, or true spherical.

  Next, the semiconductor ceramic particles 100 and the pulverized material obtained by the above-described method (hereinafter also referred to as raw material pulverized material) are mechanically combined and mixed. Specifically, after the semiconductor ceramic particles 100 and the pulverized raw material are put into a mixing container in a mechanical particle compounding apparatus, the stirring blades in the container are rotated, or the stirring blades are fixed or rotated Mixing is performed while performing a mechanical complexing process by rotating the mixing container. At this time, a mechanical action including a compressive force, a shear force, and an impact force can be applied to the individual semiconductor ceramic particles 100 and the raw material pulverized material by rotating the mixing container and the stirring blade at high speed. Thereby, as a result, the resin layer 320 in which the powder of the raw material pulverized material is combined is formed so as to cover the surface of the semiconductor ceramic particle 100. That is, according to the manufacturing method according to the present embodiment, the desired high-voltage protection particles 110 are simply obtained by performing the above-described mechanical complexation process when the semiconductor ceramic particles 100 and the raw material pulverized material are mixed. It becomes possible to obtain functional particles having new characteristics that cannot be obtained simply by mixing different kinds of particles.

  For example, the rotational speed of the stirring blades may be set to a peripheral speed of 1 m / s to 50 m / s. In particular, the lower limit value of the rotational speed of the stirring blade or the like may be set to a peripheral speed of 7 m / s or higher, or a peripheral speed of 10 m / s or higher from the viewpoint of effectively performing the mechanical complexing process. On the other hand, the upper limit value of the rotational speed of the stirring blade or the like may be, for example, a peripheral speed of 35 m / s or less, or a peripheral speed of 25 m / s or less, from the viewpoint of suppressing heat generation and preventing excessive crushing during the mechanical compounding process. Also good.

  The processing power of the mechanical particle composite device may be, for example, 0.3 kW or more and 1.5 kW or less, 0.4 kW or more and 1.1 kW or less, or 0.5 kW or more and 1 kW or less. . By doing so, the powder made of the cured resin can be efficiently combined on the surface of the semiconductor ceramic particle 100.

  Here, in order to produce the high-voltage protection particle 110 according to the present embodiment, it is preferable to employ a mechanical compounding process that applies a mechanical action including the compression force, shearing force, and impact force described above. More specifically, the manufacturing method according to the present embodiment preferably employs a dry granulation process that does not include a step of using a liquid as the mechanical complexing process. By doing so, it is possible to control the covering state at the size level of the material particles covering the surface of the semiconductor ceramic particle 100, and as a result, it is possible to form the resin layer 320 having a highly homogenized composition.

  Here, the mechanical particle compounding device refers to a raw material such as a plurality of types of powders by applying a mechanical action including a compressive force, a shearing force and an impact force to the raw materials such as a plurality of types of powders. It is an apparatus that can obtain a powder in which they are bonded together. As a method of applying a mechanical action, a rotating body having one or a plurality of stirring blades and the like and a mixing container having an inner peripheral surface close to a tip portion of the stirring blades and the like are provided, and the stirring blades and the like are rotated. Examples thereof include a method and a method of rotating a mixing container while fixing or rotating a stirring blade or the like. The shape of the stirring blade is not particularly limited as long as a mechanical action can be applied, and examples thereof include an elliptical shape and a plate shape. Further, the stirring blade or the like may have an angle with respect to the rotation direction. Moreover, you may process a groove | channel etc. in the inner surface of a mixing container.

  Specific examples of the mechanical particle compounding device include hybridization by Nara Machinery Co., Ltd., kryptron by Kawasaki Heavy Industries, Ltd., mechanofusion and nobilta by Hosokawa Micron, theta composer by Tokusu Kosakusha, mechano mill by Okada Seiko, Ube A CF mill manufactured by Kosan Co., Ltd. may be mentioned, but not limited thereto.

Although the temperature in the container during mixing is set according to the raw material, for example, a condition of 5 ° C. or more and 50 ° C. or less can be mentioned. And it is good also as 25 degrees C or less. However, it is also possible to process the container in a state where the organic matter is melted by heating.
Moreover, although mixing time is set according to a raw material, it is mentioned as conditions for 30 seconds or more and 120 minutes or less, for example. The lower limit of the mixing time may be 1 minute or more, or 3 minutes or more from the viewpoint of effectively performing the mechanical complexing process. On the other hand, the upper limit value of the mixing time may be 90 minutes or less or 60 minutes or less from the viewpoint of productivity.

In the above, the aspect of the high-voltage protection particle 110 according to the present embodiment has been described by taking as an example the case where it is assumed that the surface of the semiconductor ceramic particle 100 is covered with one resin layer 320. The particles may have a mode described later for the purpose of improving the storage stability. In addition, when the aspect mentioned later is employ | adopted, the fluctuation | variation of the mixing | blending by the component which comprises the resin layer 320 reacts at the time of the preservation | save of the high voltage protective particle 110 which concerns on this embodiment can be suppressed.
Further, in the following, a modification example in which the resin layer 320 is formed of a resin material including a thermosetting resin, a curing agent, and a curing accelerator will be described. In addition, the aspect of the high voltage protective particle 110 according to the present embodiment is not limited to the following example.

(First modification)
The high voltage protective particle 110 according to the present modification covers the semiconductor ceramic particle 100, the first resin layer formed so as to cover the surface of the semiconductor ceramic particle 100, and the surface of the first resin layer. And a second resin layer formed as described above.

In the high-voltage protection particle 110 according to this modification, the first resin layer includes any one of a thermosetting resin, a curing agent, and a curing accelerator, and the other two are the second resin layer. Included.
Alternatively, any two of the thermosetting resin, the curing agent, and the curing accelerator are included in the first resin layer, and the other one is included in the second resin layer.

  More specifically, among the thermosetting resin, the curing agent, and the curing accelerator, the curing agent and the curing accelerator are included in the same resin layer, and the thermosetting resin is included in another resin layer. One of the first resin layer and the second resin layer includes a curing agent and a curing accelerator, and the other includes a thermosetting resin, thereby further improving the storage stability of the high voltage protective particles 110. Can be improved. For example, deterioration over time when stored at 40 ° C. can be effectively suppressed.

  Further, as another specific aspect according to this modification, among the thermosetting resin, the curing agent, and the curing accelerator, the thermosetting resin and the curing agent are included in the same resin layer, and the curing accelerator is different. The structure is included in the resin layer. One of the first resin layer and the second resin layer includes a thermosetting resin and a curing agent, and the other includes a curing accelerator, thereby further improving the storage stability of the high voltage protective particles 110. Can be improved. For example, deterioration over time when stored at 40 ° C. can be effectively suppressed.

  Moreover, in the high voltage protective particle 110 according to the present modification, an intervening layer that separates them may be provided between the first resin layer and the second resin layer.

(Second modification)
The high-voltage protection particles 110 according to the present embodiment may be composed of a so-called particle group in which two or more different particles are mixed. In the following, this modified example will be described by mixing two or more different high voltage protective particles 110 as a high voltage protective particle group.

  The high-voltage protective particle group according to this modification includes semiconductor ceramic particles 100, first particles composed of a first resin layer formed so as to cover the surface of the semiconductor ceramic particles 100, and semiconductor ceramic particles 100. And second particles composed of a second resin layer formed so as to cover the surface of the semiconductor ceramic particle 100.

  In the present modification, the first resin layer and the second resin layer can employ the same configuration as that of the first modification described above.

<Semiconductor device>
The semiconductor device according to the present embodiment includes a substrate, a semiconductor element mounted on the substrate, and a resin cured material obtained by curing the material including the high voltage protective particles 110 described above, and seals the semiconductor element. And a stop material. By so doing, even when a surge voltage is generated in such a semiconductor device, the varistor characteristics of the above-described high voltage protective particles 110 can be effectively expressed, and as a result, the semiconductor device is mounted on the semiconductor device. The semiconductor device can be effectively protected from overvoltage. In particular, according to the semiconductor device according to the present embodiment, when a surge voltage is generated in the semiconductor device, the semiconductor ceramic particles contained in the high-voltage protection particles 110 can act as a bypass circuit.
In addition, the durability against the surge voltage described above tends to become apparent when the semiconductor element is a light emitting diode element.

  First, examples of the semiconductor element include an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, and a solid-state imaging element. Examples of the semiconductor device according to the present embodiment include a ball grid array (BGA), a MAP type BGA, and the like. Also, chip size package (CSP), quad flat non-ready package (QFN), wafer level package (WLP) such as Fan In WLP and Fan Out WLP, small outline non-ready package (SON) The present invention can be applied to forms such as lead frame / BGA (LF-BGA).

  In addition, the semiconductor device according to this embodiment can be mounted on an electronic device or the like as it is or after being completely cured at a temperature of about 80 ° C. to 200 ° C. for about 10 minutes to 10 hours.

  Hereinafter, with respect to the semiconductor device according to the present embodiment, a lead frame or a circuit board, one or more semiconductor elements stacked or mounted in parallel on the lead frame or the circuit board, a lead frame or a circuit board, and the semiconductor element The present invention will be described by taking as an example a case where a bonding wire for electrically connecting the semiconductor element and a sealing element for sealing the semiconductor element and the bonding wire is provided, but the present invention is limited to the one using the bonding wire. Instead, it may be a flip chip type semiconductor device electrically connected by bumps arranged in an array.

3 and 4 are views showing a cross-sectional structure of an example of the semiconductor device according to the present embodiment.
The semiconductor device shown in FIG. 3 is obtained by sealing a semiconductor element mounted on a lead frame. A semiconductor element 401 is fixed on a die pad 403 via a die bond material cured body 402. The electrode pad of the semiconductor element 401 and the lead frame 405 are connected by a wire 404. The semiconductor element 401 is sealed with a sealing material 406 made of a cured resin obtained by curing a material containing the high voltage protective particles 110.

  The semiconductor device shown in FIG. 4 is obtained by sealing a semiconductor element mounted on a circuit board, and the semiconductor element 401 is fixed on the circuit board 408 via a die bond material cured body 402. The electrode pad 407 of the semiconductor element 401 and the electrode pad 407 on the circuit board 408 are connected by a wire 404. Further, only one side of the circuit board 408 on which the semiconductor element 401 is mounted is sealed with a sealing material 406 made of a cured resin obtained by curing a material containing the high voltage protective particles 110. The electrode pad 407 on the circuit board 408 is bonded to the solder ball 409 on the non-sealing surface side on the circuit board 408 inside.

The sealing material according to the present embodiment may be formed of a resin material composed of the high voltage protective particles 110, or may be formed of a resin composition in which the high voltage protective particles 110 are blended as a filler.
Here, when the sealing material according to the present embodiment is formed of the resin composition described above, the resin composition contains a thermosetting resin and a cured resin compounded in a conventional semiconductor sealing resin composition. Various components such as an agent, a curing accelerator, a coupling agent, and a filler may be contained.

  Examples of the method for forming the sealing material include a transfer molding method, a compression molding method, an injection molding method, and a lamination method. Among these, the transfer molding method or the compression molding method is preferable from the viewpoint of sealing molding without leaving an unfilled portion. Therefore, it is preferable that the resin material forming the sealing material is processed into a granular shape, a tablet shape, or a sheet shape.

  It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these.

<Example 1>
First, the following were prepared as raw materials for forming the resin layer.
-Thermosetting resin 1: phenol aralkyl type epoxy resin containing biphenylene skeleton (Nippon Kayaku Co., Ltd., NC3000)
Thermosetting resin 2: bisphenol A type epoxy resin (YL6810, manufactured by Mitsubishi Chemical Corporation)
Curing agent 1: phenylene skeleton-containing naphthol aralkyl type phenolic resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., SN485)
Curing agent 2: Biphenylene skeleton-containing phenol aralkyl resin (Maywa Kasei Co., Ltd., MEH-7851SS, average particle size d50: 100 μm)
Release agent: Montanate ester wax (manufactured by Clariant Japan, WE-4, average particle size d50: 100 μm)
Curing accelerator: a compound represented by the following formula (1)

  Next, 37 parts by mass of the thermosetting resin 1, 16 parts by mass of the thermosetting resin 2, 9 parts by mass of the curing agent 1, 32 parts by mass of the curing agent 2, and 1 part by mass. The resin composition was obtained by kneading the raw material consisting of the above-mentioned mold release agent and 5 parts by mass of the above-mentioned curing accelerator with a three roll of 90 ° C. for 3 minutes. Next, the obtained resin composition was pulverized by a jet mill (manufactured by Seishin Enterprise Co., Ltd., single track jet mill). The pulverized product thus obtained (average particle diameter d50: 7.0 μm) was used for the mechanical particle composite treatment described later. The pulverizing condition by the jet mill was a high pressure gas pressure of 0.6 MPa.

Next, 10 parts by mass of the pulverized product and 90 parts by mass of semiconductor ceramic particles (manufactured by CERAON, microvaristor, average particle size d50: 50 μm) were mechanically combined by a method described later. . Specifically, 10 parts by mass of the pulverized product and 90 parts by mass of semiconductor ceramic particles were set in a casing (processing vessel) of a mechanical particle composite apparatus (manufactured by Hosokawa Micron Corporation, Nobilta). The mechanical particle compounding device (powder processing device) is rotated relative to the casing that receives the powder to be processed and the casing, and is compressed into the powder to be processed between the outer periphery and the inner surface of the casing. And a stirring blade provided with a blade portion for applying a shearing force. The semiconductor ceramic particles have a grain boundary portion made of bismuth oxide (Bi ₂ O ₃ ) and a plurality of crystal portions separated by the grain boundary portion and formed of zinc oxide (ZnO). It was.
Next, the mechanical particle compounding apparatus (powder processing apparatus) was driven for 30 minutes under the conditions of a stirring blade rotation speed of 950 rpm and a processing power of 0.5 kW. Thereafter, the particles of Example 1 were taken out of the casing. FIG. 5 shows an SEM image of the cross-sectional shape of the obtained particle, and FIG. 6 shows an SEM image of the external shape (surface shape) of the obtained particle.
As shown in FIG. 5, the particles of Example 1 were obtained by forming a resin layer composed of a thermosetting resin, a curing agent, a release agent, and a curing accelerator on the entire surface of the semiconductor ceramic particles. Met. In addition, as shown in FIG. 6, although the particles of Example 1 were partially plastically deformed, a resin formed by agglomerates of resin fine particles made of a pulverized product obtained by pulverizing with a jet mill. It was equipped with a layer.

<Example 2>
As a pulverized product used when mechanically compositing with semiconductor ceramic particles, a pulverized product obtained by previously pulverizing each raw material for forming a resin layer with a jet mill is mixed with a mixer for 5 minutes. The particles of Example 2 were obtained in the same manner as in Example 1 except that the processing power was set to 0.8 kW with respect to the point of using the mixture and the driving conditions of the mechanical particle composite device.
Here, the average particle diameter d50 of the pulverized product of each raw material contained in the mixture used for preparing the particles of Example 2 was as follows.
-Average particle diameter of thermosetting resin 1 d50: 7 μm
-Average particle diameter of thermosetting resin 2 d50: 13 μm
-Average particle diameter of curing agent 1 d50: 8 μm
-Average particle size d50 of curing agent 2: 10 μm
-Average particle size of the release agent d50: 15 μm
-Average particle size of curing accelerator d50: 10 μm
And the particle | grains of obtained Example 2 are the resin layer which consists of a thermosetting resin, a hardening | curing agent, a mold release agent, and a hardening accelerator on the whole surface of a semiconductor ceramic particle like Example 1. Was formed. In addition, the particles of Example 2 are partly plastically deformed, as in Example 1, but are agglomerated of resin fine particles made of a mixture of raw material pulverized material previously pulverized by a jet mill. It was provided with the formed resin layer.

<Comparative Example 1>
Various raw materials used in Example 1 containing semiconductor ceramic particles were prepared at the same blending ratio as in Example 1. This raw material was mixed at room temperature with a mixer (container rotating V-type blender). Mixing conditions were 10 minutes at 30 rpm. The obtained mixture was melt-kneaded with a heating roll at 80 to 100 ° C. for 5 minutes, cooled and pulverized to obtain a resin composition of Comparative Example 1 containing semiconductor ceramic particles on which no resin layer was formed. .

(Sealing between electrodes)
Sealing between electrodes was performed using the obtained particles.
A substrate having a FR-4 substrate (thickness: 0.15 mm) and a circuit layer (copper circuit, thickness: 12 μm, shortest distance between adjacent circuits: 200 μm) was used as the substrate on which the semiconductor elements are mounted. As the sealing method, the compression molding method described in the above embodiment was adopted. The molding conditions were a mold temperature of 175 ° C., a molding pressure of 3.9 MPa, and a curing time of 120 seconds.
Thereby, sealing between electrodes was performed and a structure (semiconductor device) was produced.

  Measurements and evaluations performed on the particles and structures obtained in Examples 1 and 2 are described in detail below.

<Evaluation items>
Formability: Formability was confirmed by visually observing the appearance of the substrate and checking for unfilled space between the electrodes. The case where there was no unfilling was determined as (◯), and the case where there was was (×).

・ Electrical characteristics evaluation Current / voltage characteristics between circuits flow when applied from 0V to 100V at a boosting speed of 0.5V / sec between adjacent circuits using pA meter / DC VOLTAGSOURCE SOURCE 4140B (manufactured by Agilent Technologies). The current value was measured. Based on the results thus obtained, a graph plotted on the logarithmic axis was created as shown in FIG. Next, the nonlinear coefficient and the varistor voltage were calculated from the obtained graph. Specifically, the multiplier α when the tangent line (a) of the graph on the high pressure side from the inflection point of the obtained graph is expressed by the following equation (2) is calculated as a nonlinear coefficient, and the graph of the low pressure side graph is calculated. The intersection of the tangent line (b) and the high voltage side tangent line (a) was calculated as the varistor voltage [V]. The varistor characteristics were determined as (◯) when the varistor voltage could be calculated and (×) when it was not possible.

Spiral flow: Using a low-pressure transfer molding machine (KTS-15, manufactured by Kotaki Seiki Co., Ltd.), a mold for spiral flow measurement according to EMMI-1-66, a mold temperature of 175 ° C., an injection pressure of 6.9 MPa, The particles obtained in Examples 1 and 2 were injected under a pressure holding time of 120 seconds, and the flow length was measured. The unit was cm.

-Increased viscosity: The increased viscosity of the particles obtained in Examples 1 and 2 was measured at 175 ° C using a flow characteristic evaluation apparatus (manufactured by Shimadzu Corporation, enhanced flow tester, CFT-500D). The measurement was performed under the conditions of a pressure of 10 kgf / cm ² and a capillary diameter of 0.5 mm. The unit is Pa · S.

  The evaluation results regarding the above evaluation items are shown in Table 1 below.

  Using the resin composition of Comparative Example 1, sealing between electrodes was performed by the method described above. As a result, when the nonlinear coefficient and varistor voltage values measured by the above-described method for the obtained structure were compared with the values of Examples 1 and 2 shown in Table 1 above, the nonlinear coefficient and varistor voltage were In any case, Examples 1 and 2 showed higher values. From this, it was found that the varistor characteristics produced by using the particles of Examples 1 and 2 can express better varistor characteristics than the cured resin produced by using the resin composition of Comparative Example 1.

DESCRIPTION OF SYMBOLS 10 Crystal part 20 Grain boundary part 100 Semiconductor ceramic particle 110 High voltage protective particle 320 Resin layer 401 Semiconductor element 402 Die bond material hardening body 403 Die pad 404 Wire 405 Lead frame 406 Sealing material 407 Electrode pad 408 Circuit board 409 Solder ball

Claims (11)

High-voltage protective particles used for producing a cured resin that exhibits non-linearity in which voltage-current characteristics do not follow Ohm's law,
Semiconductor ceramic particles having a grain boundary part and a plurality of crystal parts separated by the grain boundary part;
A resin layer covering the surface of the semiconductor ceramic particles;
Including high voltage protection particles.   The high voltage protective particles according to claim 1, wherein the semiconductor ceramic particles have an average particle diameter d50 of 0.01 μm or more and 150 μm or less.   The high-voltage protective particles according to claim 1 or 2, wherein the resin layer contains a thermosetting resin.   The high-voltage protective particle according to claim 3, wherein the thermosetting resin contains one or more selected from the group consisting of an epoxy resin, a phenol resin, and a maleimide resin.   The high voltage protective particles according to any one of claims 1 to 4, wherein the resin layer contains a curing agent.   The high voltage protective particles according to any one of claims 1 to 5, wherein the resin layer contains a curing accelerator.   The high-voltage protection according to any one of claims 1 to 6, wherein the crystal part includes one or more components selected from the group consisting of zinc oxide, silicon carbide, strontium titanate, and barium titanate. particle.   The said grain boundary part contains 1 or more types of components selected from the group which consists of bismuth, praseodymium, antimony, manganese, cobalt, and nickel, and these compounds, It is any one of Claim 1 thru | or 7 characterized by the above-mentioned. High voltage protective particles.   The high voltage protective particles according to any one of claims 1 to 8, wherein the resin layer is a layer made of an aggregate of resin fine particles having an average particle diameter d50 of 0.01 µm or more and 150 µm or less. A method for producing high-voltage protective particles used for producing a cured resin that exhibits nonlinearity in which voltage-current characteristics do not follow Ohm's law,
Preparing a semiconductor ceramic particle having a grain boundary part and a plurality of crystal parts separated by the grain boundary part;
Forming a resin layer covering the surface of the semiconductor ceramic particles;
A method for producing high-voltage protective particles having A substrate,
A semiconductor element mounted on the substrate;
A sealing material that is made of a resin cured material obtained by curing a material containing the high-voltage protective particles according to claim 1 and that seals the semiconductor element;
A semiconductor device comprising: