JP7603250B2 - Manufacturing method of resin powder - Google Patents

Description

The present disclosure generally relates to a method for producing a resin powder, and more specifically, to a method for producing a resin powder including a foreign matter removing step of removing foreign matter from a slurry-like resin composition.

In recent years, electronic components such as semiconductors have been installed in many electronic products, but as electronic products become more compact, the size of the electronic components is also decreasing. As a result, the distance between conductors in electronic components (the distance between wires and between bumps) is becoming increasingly narrow (fine), and for this reason, the selection of fillers and organic solids contained in the sealing materials used in electronic components is also constantly responding to the need for finer sizes.

However, as the distance between conductors becomes narrower as described above, defects in electronic components caused by metallic foreign matter in the sealing material, which was not an issue in the past, are now occurring. Therefore, Patent Document 1 proposes a method for producing an epoxy resin molding material for semiconductor sealing, in which a mixture containing epoxy resin is passed through a liquid magnetic filter to remove metallic components.

JP 2011-252042 A

However, the method of removing metal components using magnets, as described in Patent Document 1, is far from being able to guarantee the absence of metallic foreign matter. In other words, it has been difficult to obtain a sealing material with an extremely low content of foreign matter.

This disclosure has been made in light of the above-mentioned reasons, and aims to provide a method for producing resin powder that is easy to reduce the amount of foreign matter contained therein.

The method for producing a resin powder according to one embodiment of the present disclosure includes a first removal step, a molding step, an inspection step, and a second removal step. The first removal step removes metallic foreign matter from a slurry resin composition. The molding step molds the slurry resin composition into a plurality of molded bodies after the first removal step. The inspection step inspects each of the plurality of molded bodies for the presence or absence of foreign matter that was not removed in the first removal step using an inspection device. The second removal step removes molded bodies that are inspected in the inspection step for the presence of foreign matter.

The sealing material according to one embodiment of the present disclosure contains resin powder obtained by the resin powder manufacturing method and does not contain metallic foreign matter having a size of 10 μm or more.

In one aspect of the present disclosure, the semiconductor device has a semiconductor element sealed with the sealing material.

A method for manufacturing a semiconductor device according to one aspect of the present disclosure includes a step of preparing the sealing material and a step of sealing a semiconductor element with the sealing material.

According to the present disclosure, foreign matter is removed twice, in the first removal step and the second removal step, which has the advantage that more foreign matter can be removed than in a single removal step, making it easier to reduce the amount of foreign matter contained.

1A is a schematic plan view showing one embodiment of a method for producing a resin powder according to the present disclosure, and FIG. 1B is a schematic side view showing the same.

The following describes an embodiment. However, the embodiment described below is merely one of the various embodiments of this disclosure. The following embodiment can be modified in various ways depending on the design, etc., as long as the object of this disclosure can be achieved.

(1) Resin Powder The resin powder according to the present embodiment is an aggregate of a plurality of particles, and at least one of the plurality of particles is a particle of a resin composition. In the resin powder according to the present embodiment, it is preferable that most of the plurality of particles are particles of a resin composition. In the resin powder according to the present embodiment, it is preferable that all of the plurality of particles are particles of a resin composition.

The particles contained in the resin powder have various shapes, such as rectangular parallelepipeds, cylinders, cylinders, and elliptical cylinders. The resin powder may contain particles of a single shape among these various shapes, or may contain a mixture of particles of multiple shapes.

It is preferable that the particle size is such that the length of the longest part is 50 μm or more and 2 mm or less. If it is 50 μm or less, the particles may re-agglomerate, for example, when the resin powder is stored in a bag before shipping, and if it is 2 mm or more, the process of removing the solvent from the particles, such as by evaporating it, becomes longer, which is not efficient in terms of production. It is even more preferable that the particle size is such that one side is 100 μm or more and 1 mm or less.

(1.1) Resin Composition The resin composition contained in the resin powder particles contains electrically insulating inorganic particles and a resin component.

(1.1.1) Electrically insulating inorganic particles Electrically insulating inorganic particles have electrical insulation. Electrically insulating means that the volume resistivity of the material of the electrically insulating inorganic particles is 1×10 ⁹ Ω/cm or more. Examples of materials for such electrically insulating inorganic particles include metal oxides, metal nitrides, metal carbonates, and metal hydroxides. Examples of metal oxides include alumina, fused silica, spherical silica, spherical fused silica, crystalline silica, magnesium oxide, calcium oxide, titanium oxide, beryllium oxide, copper oxide, cuprous oxide, and zinc oxide. Examples of metal nitrides include boron nitride, aluminum nitride, and silicon nitride. Examples of metal carbonates include magnesium carbonate and calcium carbonate. Examples of metal hydroxides include aluminum hydroxide and magnesium hydroxide. The material of the electrically insulating inorganic particles in the resin powder may be one type or two or more types.

The shape of the electrically insulating inorganic particles may be appropriately selected depending on the application of the resin powder, and may be, for example, spherical, flat, elliptical, tubular, wire-like, needle-like, plate-like, peanut-like, or irregular. The molten resin composition obtained by melting the resin powder is preferably spherical in that it has excellent fluidity. The shape of the electrically insulating inorganic particles in the resin powder may be one type or two or more types.

The size of the electrically insulating inorganic particles in the resin powder must be smaller than the distance between conductors in semiconductor components available on the market, and preferably should be 80-30% of the distance between conductors in those semiconductor components.

(1.1.2) Resin component The resin component includes a thermosetting resin. The thermosetting resin is a reactive compound that can undergo a crosslinking reaction by heat. Examples of the thermosetting resin include epoxy resin, imide resin, phenol resin, cyanate resin, melamine resin, and acrylic resin. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyfunctional epoxy resin, biphenyl type epoxy resin, cresol novolac type epoxy resin, and phenol novolac type epoxy resin. The polyfunctional epoxy resin is a resin having two or more epoxy groups in one molecule. Examples of the imide resin include bisallylnadimide resin. The thermosetting resin contained in the resin component may be only one type or may be two or more types. The content of the resin component is not particularly limited. The upper limit is preferably 60% by volume, more preferably 50% by volume, based on the total volume of the particles of the resin composition. The lower limit is preferably 10% by volume, more preferably 15% by volume, based on the total volume of the particles of the resin composition.

The resin component may further include a curing agent depending on the type of thermosetting resin. The curing agent is an additive that cures the thermosetting resin. Examples of the curing agent include dicyandiamide, phenol-based curing agents, cyclopentadiene, amine-based curing agents, and acid anhydrides. The phenol-based curing agent has two or more phenolic hydroxyl groups in one molecule. Examples of the phenol-based curing agent include phenol novolac resin, phenol aralkyl resin, naphthalene-type phenol resin, and bisphenol resin. Examples of the bisphenol resin include bisphenol A resin and bisphenol F resin.

The resin component may further contain a coupling agent depending on the type of thermosetting resin. Examples of silane coupling agents include epoxy silane, amino silane, titanate aluminum chelate, and zircoaluminate.

The resin component may further contain a dispersant depending on the type of thermosetting resin. This reduces the viscosity of the slurry when the slurry is shaped by printing or coating as described below, and improves the compatibility between the resin component and the electrically insulating inorganic particles, making it possible to obtain a more uniform slurry. Examples of dispersants include higher fatty acid phosphate esters, amine salts of higher fatty acid phosphate esters, and alkylene oxides of higher fatty acid phosphate esters. Examples of higher fatty acid phosphate esters include octyl phosphate esters, decyl phosphate esters, and lauryl phosphate esters.

Depending on the application of the resin powder, the resin component may further contain a thermoplastic resin, an elastomer, a flame retardant, a colorant, a thixotropy imparting agent, an ion trapping agent, a colorant, a thixotropy imparting agent, an ion trapping agent, a surfactant, a leveling agent, an antifoaming agent, or a reactive diluent. Examples of thermoplastic resins include phenoxy resins. Examples of elastomers include thermosetting elastomers and thermoplastic elastomers. Examples of flame retardants include brominated epoxy resins and antimony oxide.

(1.2) Uses of Resin Powder Resin powder is preferably used as a raw material for, for example, an encapsulant for semiconductor devices, an insulating material for printed circuit boards, etc. A manufacturing method for a semiconductor device includes a step of preparing an encapsulant containing resin powder, and a step of encapsulating a semiconductor element with the encapsulant. The step of preparing an encapsulant containing resin powder includes purchasing an encapsulant containing resin powder. The step of preparing an encapsulant containing resin powder includes manufacturing an encapsulant containing resin powder. When resin powder is used as an encapsulant for a semiconductor device, the resin encapsulation technology for semiconductor elements used in the step of encapsulating a semiconductor element with an encapsulant is not particularly limited, and examples of the technology include a transfer molding method, a compression molding method, and an underfill method. Among these, resin powder is preferably used in a compression molding method that is inexpensive in terms of process and does not use tablets of a size of several mm or more that are too large to be detected in a final inspection with X-rays.

(2) Encapsulant The encapsulant in the present disclosure is, for example, an encapsulant for a semiconductor device, and the semiconductor device includes a semiconductor element encapsulated with the encapsulant. The form of the encapsulant may be appropriately selected depending on the application, and may be, for example, a solid, liquid, paste, film, or the like. Examples of the solid form include a powder form and a tablet form. The paste form means that the encapsulant has fluidity at room temperature even without containing a solvent.

The encapsulant contains the resin powder and a curing accelerator. The curing accelerator is a catalyst that accelerates the curing of the resin component contained in the resin powder. The type of curing accelerator can be appropriately selected depending on the type of thermosetting resin contained in the resin powder, and examples of the curing accelerator include tertiary amines, tertiary amine salts, imidazole, phosphine, and phosphonium salts. As the imidazole, 2-ethyl-4-methylimidazole can be used.

The curing accelerator may be in a state where it comes into contact with the resin component when the resin component in the resin powder reacts with the curing agent to cure. Therefore, the curing accelerator may be contained in the resin composition contained in the resin powder in advance. The curing accelerator may be supplied to the resin powder by spray coating or the like before (preferably immediately before) applying the resin powder to the sealing step or during the sealing step.

Depending on the usage form of the semiconductor device to which it is applied, the encapsulant may be only a resin powder and a curing accelerator, or may contain a solvent, an ultraviolet curing resin, a thermosetting resin, a thermoplastic resin, etc. in addition to the resin powder and the curing accelerator. These resins excluding the resin powder and the curing accelerator may be liquid or solid such as powder at room temperature (25°C).

The sealing material does not contain metallic foreign matter having a size of 10 μm or more. That is, since the resin powder of the present disclosure does not contain metallic foreign matter having a size of 10 μm or more, the sealing material containing this resin powder also has a content of metallic foreign matter having a size of 10 μm or more of 0. Here, the size is the length of the longest part of the cross section of the metallic foreign matter. When the metallic foreign matter is almost spherical, the size is the particle size. The size of the metallic foreign matter is determined by the maximum particle size of the electrically insulating inorganic particles (filler) mixed into the resin powder, the size of the mesh of the filter cloth used in the filtration in the first removal process, the number and capacity of the sensors used in the inspection process, etc. Therefore, at the present time, it is possible to obtain a sealing material that does not contain metallic foreign matter of 10 μm or more. However, taking into consideration the production speed and cost of the resin powder, the sealing material may contain metallic foreign matter of 10 μm or more but not contain metallic foreign matter of 20 to 30 μm. Furthermore, the sealing material may not contain metallic foreign matter of 5 μm or more for reasons such as improving the foreign matter inspection performance of the inspection device.

(3) Manufacturing method of resin powder The manufacturing method of resin powder according to this embodiment includes a first removal step, a molding step, an inspection step, and a second removal step. That is, a slurry is prepared in a slurrying step performed as necessary, then a first removal step such as filtration and magnetic adhesion is performed, and then a molding step is performed by printing, jet dispensing, coating, or other molding to form a molded body, and then, as necessary, the molded body is dried, and in the inspection step, the molded body is inspected by an inspection device using X-rays, etc., and then, in the second removal step, the molded body determined to contain foreign matter in the inspection step is removed, and then, as necessary, a drying step for the molded body is performed. This makes it possible to provide a resin powder in which the size of foreign matter such as metal foreign matter is small and the content of foreign matter such as metal foreign matter is low. Note that the resin powder of this embodiment contains foreign matter that exceeds the inspection capacity of the inspection device. That is, the resin powder of this embodiment contains extremely small foreign matter that cannot be detected by the inspection device. In addition, the resin powder of this embodiment contains a small amount of foreign matter that cannot be detected by the inspection device. In addition, it is preferable to inspect all the molded bodies of the resin powder of this embodiment (total inspection), thereby obtaining a resin powder containing only particles with few foreign matter. However, if some foreign matter is acceptable, it is not necessary to inspect all the molded bodies.

Here, the method for producing the resin powder according to this embodiment differs depending on whether the resin composition contains a curing accelerator or not.

(4) When the resin composition contains a curing accelerator (4.1) Slurrying step In the slurrying step, a slurry-like resin composition that can be used in the next step is prepared. That is, the viscosity of a resin composition that is solid at room temperature is reduced to obtain a slurry-like (liquid) resin composition.

A method for preparing a slurry-like resin composition includes, for example, measuring and adding (blending) a powder of the above-mentioned electrically insulating inorganic particles (hereinafter, inorganic powder) and the above-mentioned resin components, a curing accelerator, and, if necessary, a solvent, and then mixing and kneading the mixture by stirring until it becomes uniform. Even if the resin composition contains a curing accelerator, the slurry-like resin composition may be prepared by heating the composition to a degree that does not cause the curing of the resin components to proceed.

The average particle size of the inorganic powder may be appropriately selected depending on the application of the resin powder. The upper limit of the average particle size of the inorganic powder is preferably 75 μm, more preferably 50 μm. The lower limit of the average particle size of the inorganic powder is preferably 1 μm, more preferably 5 μm. The average particle size of the inorganic powder refers to the particle size at an integrated value of 50% in the particle size distribution measured using a particle size distribution measuring device based on the laser scattering/diffraction method.

The proportion of inorganic powder added may be appropriately selected depending on the application of the resin powder. The upper limit of the inorganic powder content is preferably 95 parts by mass, more preferably 85 parts by mass, per 100 parts by mass of the solid content of the slurry resin composition, and the lower limit of the inorganic powder content is preferably 40 parts by mass, more preferably 50 parts by mass, per 100 parts by mass of the solid content of the slurry resin composition. If the proportion of inorganic powder is within the above range, the resin powder can be suitably used as a semiconductor encapsulant. The solid content of the slurry resin composition refers to the solid components contained in the slurry resin composition, such as electrically insulating inorganic particles and resin components, and is the amount obtained by removing the solvent from the slurry resin composition.

As the solvent, methyl ethyl ketone (MEK), N,N-dimethylformamide (DMF), acetone, methyl isobutyl ketone (MIBK), etc. can be used. Only one type of solvent may be used, or two or more types may be mixed and used. When two or more types of solvents are mixed, the mixing ratio (mass ratio and volume ratio) is not particularly limited. The content of the solvent is not particularly limited. The upper limit of the solid content in the slurry is preferably 99 mass % and more preferably 98 mass % relative to the slurry. The lower limit of the solid content in the slurry resin composition is preferably 50 mass % and more preferably 60 mass % relative to the slurry.

The components constituting the resin component, such as the thermosetting resin, may be solid or liquid at room temperature, so long as they can be prepared as a slurry resin composition. In other words, it is sufficient that the slurry resin composition has a viscosity suitable for the first removal step (filtration, magnetic adhesion, etc.) in the next step. For example, it is sufficient that the slurry resin composition has a viscosity of about several Pa·s at room temperature.

(4.2) First Removal Step The first removal step is a step of removing relatively large foreign matter and metallic foreign matter (hereinafter, metallic foreign matter) from the slurry resin composition. Relatively large foreign matter is removed from the slurry resin composition by filtration. Metallic foreign matter is removed from the slurry resin composition by iron removal using magnetic attraction or the like. The order of filtration and magnetic attraction is not particularly set, but since filtration can also remove non-magnetic foreign matter, magnetic attraction after filtration can remove foreign matter more efficiently.

(4.2.1) Filtration Any type of filtration can be used. The mesh size of the filter cloth should be larger than the maximum particle size of the components constituting the slurry-like resin composition and smaller than the target foreign matter such as metal foreign matter. Basically, the material of the filter cloth is not important, but in this embodiment, an organic filter cloth material is preferable in consideration of solvent resistance and the like.

(4.2.2) Magnetic attraction The purpose of magnetic attraction is to capture and remove linear metal foreign matter that may pass through the above filtration. Magnetic attraction includes iron removal to remove iron foreign matter. Metal foreign matter other than iron that is magnetically attracted can also be removed. The magnetic force of the magnet used is preferably 10,000 gauss or more. The viscosity of the slurry-like resin composition is preferably 20 Pa·s or less, more preferably 5 Pa·s or less. There is no particular lower limit for the viscosity, but it is sufficient to strike a balance between the ability to capture metal foreign matter and the process of removing the solvent and drying in the next and subsequent processes.

(4.3) Primary drying After the first removal step, it is preferable to dry the slurry resin composition by this primary drying as necessary, and adjust the viscosity of the slurry resin composition so that the next molding step is possible. For example, when the slurry resin composition is molded by screen printing in the molding step, if the viscosity of the slurry resin composition is too low, the shape of the molded body after demolding from the mask is difficult to maintain, and the presence of foreign matter is difficult to detect quickly and accurately in the inspection step. Therefore, it is desirable to dry the slurry resin composition to a viscosity of 50 to 500 Pa·s, more preferably 100 to 300 Pa·s. The drying method may be any method such as vacuum drying, heat drying, or the like. In addition, when granulation is performed by a dispenser in the next molding step, this drying step may be omitted.

(4.4) Molding process The molding process is a process in which, after the first removal process, primary drying is performed as necessary, and then the slurry resin composition is molded into a plurality of molded bodies. In this embodiment, the molding process can be performed by applying the slurry resin composition to the surface of the release substrate by printing and granulating the composition. In this embodiment, the molding process can be performed by applying the slurry resin composition to the surface of the release substrate by a dispenser and granulating the composition.

As shown in FIG. 1A, multiple molded bodies 2 are formed on the surface (upper surface) of a release substrate 1 such as a release film or sheet. In this case, multiple molded bodies 2 are molded into a predetermined shape at a predetermined interval. If the dimensions between adjacent molded bodies 2 and the shape of each molded body 2 are determined in this way, it is easy to set the position and shape of the molded body 2 to be inspected in the next inspection process. When molding multiple molded bodies 2, a slurry-like resin composition can be applied while moving the release substrate 1 along the direction of the arrow.

The shape of the molded body 2 is not particularly limited, but is formed, for example, into an elliptical cylinder with an aspect ratio of 1:2 or more. The thickness of the molded body 2 is preferably 1 mm or less. In this case, X-rays and the like can easily reach the inside of the molded body 2 in the next inspection process, making it easy to inspect for foreign objects. The aspect ratio of the elliptical cylindrical molded body 2 is the ratio of the major axis to the minor axis of the ellipse at the bottom surface of the molded body 2. The thickness of the molded body 2 is the height dimension from the surface that contacts the surface of the release substrate 1.

(4.4.1) Granulation by printing There is no problem whether the printer is a vacuum printer or a normal pressure printer, and there is no problem if it is a screen printer. The material of the mask is not particularly limited, but since the purpose of this embodiment is to reduce the metal foreign matter contained in the resin powder, an organic insulating mask or a ceramic mask is preferable, and it is preferable not to use a metal mask, especially a SUS mask. Regarding the thickness of the mask, there is no problem as long as a molded body having a particle size of 50 μm to 2 mm, which is the size of the final product (resin powder), can be molded. Regarding the opening size of the mask, it is preferable that it is in the range of 50 μm to 2 mm, which is the size of the final product mentioned above, and a mesh-shaped one can also be used. In addition, there is no particular problem with the material of the squeegee, but it is preferable to use an organic material or an inorganic material so that the metal material part and the slurry-like resin composition do not come into contact with each other.

(4.4.2) Granulation by Dispensing The dispenser may be of the usual air type or jet type. There is no problem as long as a molded body with a product size of 50 μm to 2 mm can be produced. In addition, it is preferable to use organic or inorganic materials for the parts of the device that come into contact with the slurry, and to prevent contact between the metal parts and the slurry-like resin composition.

(4.5) Drying process (secondary drying)
The drying step is a step of evaporating the solvent remaining in the molded body 2 to dry it. The drying step is a final drying step in which the solvent is removed from each molded body 2. In the drying step, preferably The molded body 2 is dried so that the solvent is 5 wt % or less, more preferably 1 wt % or less, based on the entire molded body 2. Examples of the drying method include vacuum drying and heat drying. When drying is used, the vacuum level and time must be set so that the final shape of the resin powder particles does not change. When drying by heating, the temperature must be set so that the catalyst, hardener, and resin do not harden. and time.

(4.6) Inspection process The inspection process is a process in which an inspection device 3 such as an X-ray generator is used to inspect each of the multiple molded bodies 2 for the presence or absence of foreign matter that was not removed in the first removal process. For example, the foreign matter that was not removed in the first removal process is a metal foreign matter, which is less penetrable by X-rays than the resin component in the molded body 2 and can be inspected by X-rays.

The X-ray source is generally called a microfocus X-ray source, and preferably has a tube voltage of 30 to 100 kV, a tube current of 0.1 to 200 μA, and a maximum spot size of 50 μm or less. Examples of detectors include charge-coupled devices (CCDs) and CMOS, or X-ray image intensifiers (X-ray II), line sensors, and TDI (Time Delay Integration) cameras. The device is configured, for example, in the following order: detector - resin powder on a release substrate - X-ray source. The release substrate (release film) used here is preferably transparent to X-rays.

X-rays pass through the resin powder and release base material, but do not pass through metallic foreign matter, and are irradiated onto the detector. The transmitted X-rays cause the scintillator on the surface side of the detector to emit light at the points where they are received, and this light emission is read by a CCD camera and output as an image. Alternatively, a method of directly converting X-rays without passing through a scintillator may be used.

Then, image processing is performed based on the image obtained with the above configuration to determine the presence or absence of foreign matter, and a pass/fail judgment is made for each particle of the resin powder. If there is no or insufficient light emission signal for three or more consecutive pixels, it is determined that a metallic foreign matter is present and a fail judgment is made. This is because if there are three or fewer pixels, there is a high possibility that electrical noise etc. will be erroneously detected as a metallic foreign matter.

In the above, the inspection process using the X-ray inspection method is described, but the present invention is not limited to this, and other inspection methods may be used to inspect the presence or absence of foreign matter. For example, the presence or absence of foreign matter in the molded body 2 may be inspected using a magnetic detection method. The magnetic detection method is a method of detecting magnetism from metallic foreign matter contained in the molded body 2 by imparting magnetism to the molded body 2. The presence or absence of foreign matter in the molded body 2 may also be inspected using a magnetic detection method. As a magnetic detection method, a sensor coil type (for example, a metal detector, a TMR sensor, etc.) is used to detect magnetism from metallic foreign matter contained in the molded body 2. The presence or absence of foreign matter in the molded body 2 may also be inspected using a thermal detection method. The thermal detection method is a method of detecting the presence or absence of metallic foreign matter by applying heat to the molded body 2 and observing the difference in thermal conductivity between the resin component and the metallic foreign matter with a thermo camera or the like. The presence or absence of foreign matter in the molded body 2 may also be inspected using an ultrasonic detection method. The ultrasonic detection method is a method of detecting the presence or absence of metallic foreign matter by applying ultrasonic waves to the molded body 2 and reflecting the ultrasonic waves from the molded body 2. In this way, it is preferable to inspect for foreign objects in a non-destructive manner on the molded body 2.

(4.7) Second Removal Process (Rejected Product Removal Process)
After the inspection process, similar to the above (4.7), this is a process of removing molded bodies that have been inspected for the presence of foreign matter in the inspection process. After the inspection process, the coordinate position of a rejected product (e.g., molded body X in FIG. 1B) that has been determined to have a foreign matter of a predetermined size or more is sent to a rejected product removal device, and the rejected product removal device removes the product from the line. The mechanism for removing the resin powder that has been determined to be a rejected product in the above-mentioned inspection process includes, for example, a mechanism for picking and removing the powder with a jig such as tweezers, a mechanism for adsorbing and removing the powder with a head equipped with a vacuum mechanism, and a mechanism for pushing up the molded body 2 through a release substrate to lift the resin powder and remove it with an air blow.

(5) When the resin composition does not contain a curing accelerator (5.1) Slurrying process In the slurrying process, the viscosity of a resin composition that is solid at room temperature is reduced to obtain a slurry (liquid) resin composition, as described above. However, since the resin composition does not contain a curing accelerator, a slurry resin composition can be obtained by heating. Therefore, since a slurry resin composition can be obtained without using a solvent, the molded body can be efficiently dried in the primary drying and drying processes described below. Note that even if the resin composition does not contain a curing accelerator, a small amount of solvent may be used.

A method for preparing a slurry-like resin composition includes, for example, measuring and adding (blending) a powder of the above-mentioned electrically insulating inorganic particles (hereinafter, inorganic powder) and the above-mentioned resin components, and optionally a solvent, and then mixing and kneading the mixture by stirring or the like until it becomes uniform. No curing accelerator is added here.

The viscosities of the inorganic powder, the solvent, and the slurry-like resin composition are the same as those in (4.1) above. The slurry-like resin composition only needs to have a viscosity suitable for the first removal step (filtration, magnetic adhesion, etc.) in the next step, so it is heated to, for example, about 200°C to melt it.

(5.2) First Removal Step The first removal step can be performed by filtration or magnetic attraction, similar to the step described in (4.2) above.

(5.3) Cooling After the first removal step, it is preferable to cool the slurry resin composition in a cooling step as necessary, and adjust the viscosity of the slurry resin composition so that the next molding step can be performed. In this case, as in (4.3) above, it is desirable to cool the slurry resin composition to a viscosity of 50 to 500 Pa·s, more preferably 100 to 300 Pa·s. For example, the slurry resin composition is cooled to a temperature of about 150°C.

(5.4) Molding Step In the molding step, a molded body is molded by printing or the like, similarly to the step described in (5.4) above. However, this molding step is preferably performed under heating so that the slurry-like resin composition can be easily molded.

(5.5) Drying Step The drying step is a step of evaporating the solvent remaining in the molded body 2 to dry it, similar to the above (4.5).

(5.6) Inspection Step Similar to the above (4.6), the inspection step is a step of inspecting each of the multiple molded bodies 2 for the presence or absence of foreign matter that was not removed in the first removal step.

(5.7) Second Removal Process (Rejected Product Removal Process)
After the inspection step, similarly to the above (4.7), this is a step of removing any molded articles that have been found to contain foreign matter in the inspection step.

(6) Manufacturing method of encapsulant (6.1) When the resin composition contains a curing accelerator When the resin composition contains a curing accelerator, the resin powder obtained in the above "(4) When the resin composition contains a curing accelerator" can be used as an encapsulant. Therefore, the manufacturing method of the resin powder in the above "(4) When the resin composition contains a curing accelerator" is the manufacturing method of the encapsulant.

(6.2) When the resin composition does not contain a curing accelerator When the resin composition does not contain a curing accelerator, a sealant can be obtained by supplying a curing accelerator to the resin powder obtained in the above "(5) When the resin composition does not contain a curing accelerator". Therefore, the method for producing a resin powder in the above "(5) When the resin composition does not contain a curing accelerator" can be further provided with a step of supplying a curing accelerator to the resin powder, thereby forming a method for producing a sealant.

The means for supplying the curing accelerator can be spray coating, etc. The curing accelerator can be supplied to the resin powder before (just before) the resin powder is used for sealing molding, or during sealing molding.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

The raw materials for the slurry are shown below.

[Electrically insulating inorganic particles]
Spherical silica (fused silica): ("FB5SDC" manufactured by Denka Co., Ltd., _D50 : 6 μm)
[Intentional metal foreign bodies]
As the intentional foreign metal substance, a nearly spherical foreign metal substance, "BPC300-45" ( _D50 is about 30 μm) manufactured by Ito Kiko Co., Ltd., was used. As a nearly linear foreign metal substance, a SUS piano wire with a diameter of 10 μm was used, which was then cut to a length of 100 μm to prepare the foreign metal substance.

[Resin component]
(Epoxy resin)
Bisphenol A type epoxy resin Biphenyl aralkyl type epoxy resin Biphenyl type epoxy resin Biphenyl aralkyl type phenolic resin Novolac type phenolic resin (curing accelerator)
2-Ethyl-4-methylimidazole (coupling agent)
・Mercaptosilane (solvent)
The solvents used were methyl ethyl ketone (MEK, boiling point: 79° C.) and N,N-dimethylformamide (DMF, boiling point: 153° C.). However, any solvent may be used as long as it is compatible with the resin and can reduce the viscosity without deteriorating the curing performance of the resin, and there is no problem.

The following describes how to measure the NG rate of metal foreign matter inspection using X-rays, particle size, secondary agglomeration confirmation, metal foreign matter, short circuit defects using actual equipment, and the amount of remaining solvent.

[NG rate of metal foreign body inspection by X-ray]
The molded body is irradiated with X-rays from an X-ray generator, and a camera is used to detect metallic foreign bodies. In this case, images are simultaneously taken from three directions by the camera, and foreign bodies with a thickness of 10 μm or more can be visually confirmed on a monitor. 1,000 particles of resin powder (molded body) are placed on a release film and transported, and the number of particles determined to be defective (NG) is confirmed by a detector (camera).

[Particle size (size of resin powder particles)]
The size of the granules was measured by the weight fraction of the sieve mesh-on product. Specifically, 100 g of the sample was placed on a stack of sieve meshes of 2000 mm, 850 μm, 500 μm, 300 μm, and 100 μm, and the stack was shaken for 5 minutes, and the weight of the on-product was measured. When the mesh-on product was 90% or more in any one layer, it was defined as sharp, and otherwise as broad.

[Secondary aggregation confirmation]
5 kg of the sample was placed in a bag, a weight of 5 kg was applied, and the bag was left for 24 hours, after which the weight of the secondary agglomerates was confirmed. A secondary agglomerate with a weight fraction of 5% or more was defined as "present," and any other value was defined as "absent."

[Metallic foreign matter]
The metallic foreign matter in the resin powder was evaluated according to the following criteria.

300 g of any powder sample was taken and dissolved in acetone, after which metal was extracted using a 6000 gauss magnetic rod. The weight fraction of the resulting metal foreign matter relative to the resin powder was calculated and a quantitative evaluation was performed. The particle shape of the metal foreign matter was measured from images of each particle using a particle image analyzer ("PIPA-1" manufactured by Seishin Enterprise Co., Ltd.), and the average and maximum values of each measurement were confirmed. This device uniformly disperses the sample using an automatic dispersion unit, and the physical properties of the sample are measured by analyzing still images of the sample.

[Short circuit failure in actual device]
Using an evaluation TEG with a wire thickness of 20 μm and a wire pitch of 40 μm, if a short circuit occurred after molding and a metallic foreign matter was found at the short circuit point, the product was deemed defective and the defective rate was calculated.

[Residual Solvent Amount]
The amount of residual solvent in the resin powder was measured as follows. 5 g of the resin powder was placed in a dryer at 175° C. for 15 minutes to remove the volatile matter (solvent). The mass loss of the resin powder before and after the dryer was measured. The mass loss relative to the mass of the resin powder before the dryer was calculated, and this was taken as the amount of residual solvent.

(Examples 1 and 2)
A resin composition in which each component was blended according to the blending ratio shown in Table 1 was mixed with a solvent to obtain a slurry-like resin composition.

(Comparative Example 1)
A slurry-like resin composition was obtained according to the blending ratio shown in Table 1, and resin powder was obtained by creating particles with a granule size of 100 μm or less on one side.

(Comparative Example 2)
A slurry was obtained according to the blending ratio shown in Table 1, and particles with a granule size of 2 mm or more on one side were prepared to obtain a resin powder.

(Comparative Example 3)
According to the blending ratio shown in Table 1, a resin powder was prepared using a kneader or the like and granulated.

(Comparative Example 4)
According to the blending ratio shown in Table 1, a slurry-like resin composition was obtained, but in Example 1, only the filtration step was omitted, and a resin powder was produced.

(Comparative Example 5)
A slurry-like resin composition was obtained according to the compounding ratio shown in Table 1, but in Example 1, only the iron removal step was omitted to produce a resin powder.

Note that "⇒" in the table indicates that the data is the same as the column to the left of the arrow.

1 Release substrate 2 Molded body

Claims (5)

a first removal step of removing metal foreign matter from the slurry-like resin composition;
After the first removing step, a molding step of molding the slurry resin composition into a plurality of molded bodies at predetermined intervals into a predetermined shape by supplying the slurry resin composition to a surface of a release substrate;
an inspection step of inspecting each of the plurality of molded bodies on the release substrate for the presence or absence of foreign matter that has not been removed in the first removal step by an inspection device;
a second removal step of removing the molded body inspected for the presence of foreign matter in the inspection step from the release substrate;
and a step of obtaining a resin powder composed of an aggregate of a plurality of molded bodies after removing the molded bodies inspected for the presence of metal foreign matter in the second removal step.
A method for producing resin powder. The molded body has a thickness of 1 mm or less.
A method for producing the resin powder according to claim 1. The first removal step includes removing the metal foreign matter by at least one of magnetic attraction and filtration.
A method for producing the resin powder according to claim 1 or 2. A slurrying step of preparing the slurry-like resin composition by mixing a resin that is solid at room temperature, a curing accelerator, and a solvent, which is performed before the first removal step;
The method further includes a drying step of evaporating the solvent from the molded body before the inspection step.
The method for producing the resin powder according to any one of claims 1 to 3. The method further includes a slurrying step of preparing the slurry-like resin composition by heating and melting a resin that is solid at room temperature in a state that does not contain a curing accelerator, prior to the first removal step.
The method for producing the resin powder according to any one of claims 1 to 3.

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