TW201934649A - Method for manufacturing electronic device - Google Patents

Abstract

This method for producing an electronic device comprises: a step for preparing a member that is provided with a copper circuit on the surface; a coating step for forming an OSP film on the copper circuit by applying a preflux agent onto the surface of the member; and a sealing step for sealing the copper circuit by means of a resin composition for sealing. The sealing step is carried out without performing a cleaning step for removing the OSP film, which has been formed in the coating step; the resin composition for sealing contains an epoxy resin, a curing agent and an adhesion promoter; and the preflux agent contains an imidazole compound.

Description

Manufacturing method of electronic device

The invention relates to a method for manufacturing an electronic device.

Various techniques have been developed for the purpose of improving the fluidity of sealing materials for mold underfill used in the manufacture of electronic devices. As such a technique, the technique described in patent document 1, for example is mentioned. According to Patent Document 1, it is described that when a filler that has been surface-treated with N-phenyl-3-aminopropyltrimethoxysilane is mixed with a resin material, it can cover a wide range of shear rates. Low viscosity. Further, according to Patent Document 1, it is described that when a resin composition is prepared using a filler having a surface treated with N-phenyl-3-aminopropyltrimethoxysilane, the cohesiveness of the filler decreases.

Patent Document 1: Japanese Laid-Open Patent Publication No. 2015-140389

For a copper circuit arranged on a substrate such as a printed wiring board, for example, a pre-flux agent is applied in order to suppress oxidation of the copper circuit in a production step thereof. As a result, an oxide film (Organic Solderability Preservative film: OSP film, organic solder resist film) is formed on the surface of the copper circuit to prevent oxidation of the copper circuit.

In a conventional method of manufacturing an electronic device, when a copper circuit is sealed with a sealing resin composition, the OSP film is washed and removed in advance. However, the step of removing the OSP film causes a reduction in the productivity of the electronic device.
In order to improve the productivity of an electronic device, the present inventors are considering using the sealing material described in Patent Document 1 to manufacture an electronic device without removing the OSP film by washing. However, it has been confirmed that when a conventional sealing material is used, the adhesion between the hardened material of the sealing material and the copper circuit is reduced.

An object of the present invention is to provide a method for manufacturing an electronic device that improves the adhesion between a cured resin composition for sealing and a copper circuit on the premise that a cleaning step for removing the OSP film is not performed.

The present inventors investigated the raw material components of the sealing resin composition in order to improve the adhesion between the hardened material of the sealing resin composition and the copper circuit on the premise that the washing step of removing the OSP film was not performed. As a result, it was found that when the sealing resin composition contains a specific adhesion aid, the OSP film is broken when the sealing resin composition is introduced, and even if the washing step is not performed, the adhesion between the sealing resin composition and the copper circuit is also improved. Will improve.
Based on the above, the present inventors have found that by using a specific adhesion aid, the adhesion between the sealing resin composition and the copper circuit is improved, and the present invention has been completed.

According to the present invention, a method for manufacturing an electronic device is provided, which includes:
Steps to prepare components with copper circuits on the surface;
A coating step of forming an OSP film on the copper circuit by applying a pre-flux on the surface; and a sealing step of sealing the copper circuit by a sealing resin composition,
The aforementioned sealing step is performed without performing a cleaning step of removing the aforementioned OSP film formed in the aforementioned coating step,
The resin composition for sealing includes an epoxy resin, a hardener, and an adhesion aid,
The aforementioned pre-flux contains an imidazole compound.

According to the present invention, it is possible to provide a method for manufacturing an electronic device in which the adhesion between a sealing resin composition and a copper circuit is improved even when a copper circuit having an OSP film is sealed.

Hereinafter, embodiments of the present invention will be described.

The manufacturing method of an electronic device according to this embodiment is a method of manufacturing an electronic device by sealing a member having a copper circuit on a surface with a sealing resin composition. The method for manufacturing an electronic device includes preparing copper on the surface. A step of circuit components; a coating step of forming an OSP film on the copper circuit by applying a pre-flux on the surface; and a sealing step of sealing the copper circuit by a sealing resin composition, the foregoing The sealing step is performed without performing a cleaning step of removing the OSP film formed in the coating step. The sealing resin composition includes an epoxy resin, a hardener, and an adhesion aid, and the pre-flux includes an imidazole compound.

For a copper circuit arranged on a substrate such as a printed wiring board, for example, a pre-flux for suppressing oxidation of the copper circuit is applied in a production step thereof. As a result, an OSP film is formed on the surface of the copper circuit to prevent oxidation of the copper circuit.

In a conventional method of manufacturing an electronic device, when a copper circuit is sealed with a sealing resin composition, an OSP film for suppressing oxidation of the copper circuit is not removed by a washing step. Thereby, if a conventional copper resin circuit is sealed and an electronic device is manufactured using the conventional sealing resin composition without removing the OSP film, the OSP film remains. This residual OSP film may reduce the adhesion between the copper circuit and the sealing resin composition.
In addition, when the cleaning step for removing the OSP film is performed, the productivity of the electronic device is reduced.

Therefore, the present inventors investigated the raw material components of the sealing resin composition in order to improve the adhesion between the hardened material of the sealing resin composition and the copper circuit on the premise that the cleaning step of removing the OSP film was not performed. As a result, it was found that when the sealing resin composition contains a specific adhesion aid, the OSP film is broken when the sealing resin composition is introduced, and even if the washing step is not performed, the adhesion between the sealing resin composition and the copper circuit is also improved. Will improve.
The detailed mechanism is uncertain, but the reason is speculated as follows.
First, a flux is applied to a copper circuit before the imidazole compound is contained, thereby forming a complex by the interaction of the imidazole compound and a copper atom containing the copper circuit. The OSP film has a complex layer composed of the complex. Further, when the sealing resin composition contains a specific adhesion aid described later, when the copper circuit is sealed by the sealing resin composition, the complex formed by the imidazole compound and the copper atom in the complex layer can be destroyed. Accordingly, when a copper circuit is sealed using a sealing resin composition containing a specific adhesion aid, the OSP film can be broken while being sealed. Furthermore, it is speculated that the interaction between the lone electron pair provided in the adhesion promoter and the copper atom of the copper circuit forms a complex with the copper atom of the copper circuit. Thereby, compared with the conventional sealing resin composition, the hardened | cured material of the sealing resin composition containing a specific adhesion adjuvant can improve the adhesiveness with respect to a copper circuit.
Based on the above, it is presumed that in the method for manufacturing an electronic device according to this embodiment, the adhesion between the hardened material of the sealing resin composition and the copper circuit can be improved without performing the cleaning step of removing the OSP film.

The OSP film includes, in addition to the above-mentioned complex layer, an imidazole layer formed of, for example, an imidazole compound that does not form a complex. Here, the imidazole layer is formed by the intermolecular force of the imidazole compound, and the intermolecular interaction is weaker than that of the complex layer formed by the ionic bonding of the complex. As a result, the method for manufacturing an electronic device according to this embodiment may destroy the complex layer made of the complex, and may damage the imidazole layer. Therefore, according to the manufacturing method of the electronic device according to this embodiment, the adhesion between the hardened material of the sealing resin composition and the copper circuit can be improved even when the washing step of removing the OSP film is not performed.

First, the raw material components of the sealing resin composition used in the manufacturing method of the electronic device of this embodiment are demonstrated.
The resin composition for sealing contains an epoxy resin, a hardener, and a tackifier.

(Epoxy resin)
The sealing resin composition of this embodiment contains an epoxy resin. The epoxy resin is not limited, and regardless of its molecular weight and molecular structure, all monomers, oligomers, and polymers having two or more epoxy groups in one molecule can be used.
Specific examples of the epoxy resin include, for example, biphenyl type epoxy resins; bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and tetramethylbisphenol F type epoxy resin. Epoxy resins; 茋 -type epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resin, cresol novolac-type epoxy resin; examples are triphenol methane-type epoxy resin, alkyl modified triphenol Multifunctional epoxy resins such as triphenyl epoxy resins such as methane epoxy resins; phenol aralkyl epoxy resins with phenylene skeleton; naphthol aralkyl epoxy resins with phenylene skeleton Phenol aralkyl type epoxy resin having a biphenylene skeleton (biphenyl aralkyl type epoxy resin), naphthol aralkyl epoxy resin having a biphenyl group, etc. Epoxy resins; dihydroxynaphthalene-type epoxy resins, naphthol-type epoxy resins such as epoxy resins obtained by dipropylation of dihydroxynaphthalene dimers; trimeric isocyanate tripropylene oxide Ester, monoallyl trimer isocyanate dipropylene oxide and other epoxy resins containing trinuclear; dicyclopentadiene modification Cross-linked cyclic hydrocarbons such as phenolic epoxy resins are modified by phenolic epoxy resins. As the epoxy resin, one of them may be used alone, or two or more of them may be used in combination.

(hardener)
The sealing resin composition of this embodiment contains a hardener. As the curing agent contained in the sealing resin composition, specifically, there are three types, such as a compound addition curing agent, a catalyst type curing agent, and a polyaddition curing agent.

As the hardening agent used for the above-mentioned hardening agent, specifically, in addition to aliphatic polyamines such as diethylene glycol triamine (DETA), triethylene glycol tetramine (TETA), and m-xylene diamine (MXDA), diamine In addition to aromatic polyamines such as aminodiphenylmethane (DDM), m-phenylenediamine (MPDA), and diaminodiphenylhydrazone (DDS), examples include dicyandiamine (DICY) and organic acids. Polyamine compounds such as dihydrazine; including alicyclic anhydrides such as hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (MTHPA), 1,2,4-trimellitic anhydride (TMA), pyromelic acid Acid anhydrides such as dianhydride (PMDA), benzophenone tetracarboxylic acid (BTDA), and other aromatic anhydrides; phenol resin-based hardeners such as novolac phenol resin, polyvinyl phenol, and aralkyl phenol resin; polysulfides Polythiol compounds such as thioesters and thioethers; isocyanate compounds such as isocyanate prepolymers and block isocyanates; polyester resins containing carboxylic acids. The additional molding hardener may include one or two or more kinds selected from the above specific examples.

Specific examples of the catalyst-type hardener used as the hardener include benzyldimethylamine (BDMA), 2,4,6-tris (dimethylamine) methylphenol (DMP-30), and the like. Tertiary amine compounds; 2-methylimidazole, 2-ethyl-4-methylimidazole (EMI24) and other imidazole compounds; BF ₃ complex and other Lewis acids. As the catalyst-type curing agent, one kind or two or more kinds selected from the above specific examples can be contained.

Specific examples of the polyadditive hardener used as the hardener include: resol type phenol resin; urea resin such as methylol-containing urea resin; and methylol-containing resin Melamine resins such as melamine resins. The polyaddition hardening agent may include one or two or more kinds selected from the above specific examples.

Among the hardeners, a phenol resin-based hardener is preferably contained. Thereby, epoxy resin can be hardened suitably. Furthermore, the adhesion between the hardener and the adhesion assistant can be further improved.
As the phenol resin-based hardener, all monomers, oligomers, and polymers having two or more phenolic hydroxyl groups in one molecule can be used, and the molecular weight and molecular structure are not limited.
Specific examples of the phenol resin-based hardener used as the hardener include phenol novolac resins such as phenol novolac resin, cresol novolac resin, bisphenol novolac resin, and phenol-biphenol novolac resin; Polyphenols; polyfunctional phenol resins such as triphenylmethane phenol resins; modified phenol resins such as terpene modified phenol resins and dicyclopentadiene modified phenol resins; phenol aralkyl resins with a phenylene skeleton , Phenol aralkyl resin with biphenylene skeleton (biphenylaralkyl phenol resin), Naphthol aralkyl resin with biphenylene skeleton, Naphthol aralkyl resin with biphenylyl skeleton Phenol aralkyl type phenol resins; bisphenol A, bisphenol F and other bisphenol compounds. The phenol resin-based curing agent may include one or two or more kinds selected from the above specific examples.

(Adhesion aid)
As the adhesion promoter, those having a specific functional group are preferred.
Specific examples of the specific functional group include a thiol group, a carboxyl group, and an amine group. By having these specific functional groups, the adhesion promoter can break the OSP film. When the adhesion aid includes a lone electron pair, after the OSP film is broken, the lone electron pair interacts with copper atoms of the copper circuit, which can improve the adhesion between the hardened material of the sealing resin composition and the copper circuit.
In addition, the adhesion promoter can be used as a specific functional group by combining one or two or more of the specific examples described above.

In addition, the detailed mechanism is not clear, but as a mechanism for damaging the OSP film, it is estimated as follows.
When the adhesion promoter contains a carboxyl group as a specific functional group, it is estimated that the complex layer of the OSP film becomes acidic, the complex becomes unstable, and the OSP film can be broken.
In addition, when the adhesion promoter contains a thiol group and an amine group as specific functional groups, it is estimated that in the complex layer of the OSP film, a complex exchange reaction occurs between the adhesion promoter and the imidazole compound of the former flux. , Can destroy the OSP film.

As the amine group in this embodiment, specifically, it includes a primary, secondary, and tertiary amine group that is not incorporated into a heterocyclic ring, and a heterocyclic amine that is a primary or secondary amine group that is incorporated into a heterocyclic ring. base. As the amine group, for example, a heterocyclic amine group is preferable. Thereby, the adhesion promoter of the sealing resin composition strongly interacts with the copper atom of the copper circuit, and the adhesion can be further improved.
Here, examples of the heterocyclic amino group include tris, triazole, and the like. As three, for example, a structure represented by the following general formula (H1) is preferred. The triazole is preferably a structure represented by the following general formula (H2).

(In the general formula (H1), R is independently selected from the group consisting of a hydrogen atom, a carbon atom, a silicon atom, a nitrogen atom, a phosphorus atom, an oxygen atom, a sulfur atom, a fluorine atom, a chlorine atom, and a bromine atom. A group of one or more atoms.)

(In the above general formula (H2), R is each independently selected from the group consisting of a hydrogen atom, a carbon atom, a silicon atom, a nitrogen atom, a phosphorus atom, an oxygen atom, a sulfur atom, a fluorine atom, a chlorine atom, and a bromine atom. A group of one or more atoms.)

In the general formulae (H1) and (H2), when R contains a carbon atom, for example, an organic group having a carbon number of 1 to 30 is preferred, and an organic group having a carbon number of 1 to 10 is more preferred. Organic groups having a number of 1 to 5 are more preferred.
When R is an organic group containing a carbon atom, R preferably contains a hydroxyl group, for example.

In the general formulae (H1) and (H2), as the plurality of R, for example, at least one is preferably one or more selected from the group consisting of a carboxyl group, a thiol group, and an amine group, and at least one amine group is included. It is better. This makes it possible to break the OSP film and improve the adhesion between the hardened material of the sealing resin composition and the copper circuit.

In the general formulae (H1) and (H2), as the plurality of Rs, for example, one or more Rs preferably include one or more selected from the group consisting of a carboxyl group, a thiol group, and an amine group, and two or more R preferably contains one or more selected from the group consisting of a carboxyl group, a thiol group, and an amine group. This makes it possible to break the OSP film and improve the adhesion between the hardened material of the sealing resin composition and the copper circuit.

Specific examples of the adhesion assistant that include a carboxyl group include stearic acid.
Among the adhesion promoters, those containing a thiol group specifically include γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and 3-amino-5-mercapto -1,2,4-triazole and the like.
Among the adhesion promoters, as those containing an amine group, specifically, 4,6-diamino-1,3,5-tri-2-ethanol, 3-amino-5-mercapto-1 , 2,4-triazole and so on.

The lower limit value of the content of the adhesion promoter in the sealing resin composition is, for example, preferably 0.010 parts by mass or more, more preferably 0.015 parts by mass or more, and 0.020 parts by mass with respect to the total solid content of the sealing resin composition. The above is further preferred, 0.025 parts by mass or more is further preferred, and 0.030 parts by mass or more is particularly preferred. This makes it possible to better break the OSP film.
The upper limit of the content of the adhesion assistant in the sealing resin composition is preferably 1.0 part by mass or less, more preferably 0.7 part by mass or less with respect to the total solid content of the sealing resin composition, and 0.5 It is more preferable that the content is less than or equal to 0.3 parts by mass. This makes it possible to suppress generation of aggregation of particles and generation of insoluble foreign matter in a solvent or the like.
In addition, in this embodiment, the total solid content of the resin composition for sealing shows the total of the raw material components from which the solvent was removed.

The lower limit of the content of the adhesion promoter in the sealing resin composition is, for example, preferably 0.10 parts by mass or more, more preferably 0.15 parts by mass or more, more preferably 0.20 parts by mass or more, and 0.30 parts by mass. It is more preferable that it is more than parts, and it is particularly preferable that it is 0.40 parts by mass or more. By doing so, after the OSP film is broken, the adhesion assistant appropriately dispersed in the sealing resin composition and the copper atom appropriately interact to improve the adhesion.
The upper limit of the content of the adhesion assistant in the resin composition for sealing is, for example, preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and still more preferably 6 parts by mass or less.
In this embodiment, the amount of resin indicates the total amount of the epoxy resin and the hardener.

(Other ingredients)
According to the needs, one of various additives such as a hardening accelerator, an inorganic filler, a coupling agent, a release agent, a colorant, a flame retardant, an ion trapping agent, and a low stress agent can be appropriately blended in the sealing resin composition. Or 2 or more.

(Hardening accelerator)
The curing accelerator is not limited as long as it promotes the curing reaction of the epoxy resin and the curing agent, and the type of the epoxy resin and the curing agent can be selected.
Specific examples of the hardening accelerator include onium salt compounds, organic phosphines, tetra-substituted phosphonium compounds, phosphate betaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of sulfonium compounds and silane compounds. And other compounds containing phosphorus atoms; 2-methylimidazole, 2-ethyl-4-methylimidazole (EMI24), 2-phenyl-4-methylimidazole (2P4MZ), 2-phenylimidazole (2PZ), Imidazole compounds such as 2-phenyl-4-methyl-5-hydroxyimidazole (2P4MHZ), 1-benzyl-2-phenylimidazole (1B2PZ); exemplified by 1,8-diazine bicyclo [5.4.0] Monoene-7 or tertiary amines such as benzyldimethylamine; nitrogen atom-containing compounds such as quaternary ammonium or tertiary ammonium salts of the tertiary amine; As a hardening accelerator, you may use 1 type, or 2 or more types together in the said specific example.

(Inorganic filler)
The inorganic filler is not limited, and an appropriate inorganic filler can be selected in accordance with the structure of the electronic device and the mechanical strength and thermal characteristics required by the electronic device.
Specific examples of the inorganic filler include silicon dioxide such as fused crushed silica, fused spherical silica, crystalline silica, secondary agglomerated silica, and spherical fine powdered silica; Alumina, silicon nitride, aluminum nitride, boron nitride, titanium oxide, silicon carbide, aluminum hydroxide, magnesium hydroxide, titanium white and other metal compounds; talc; clay; mica; glass fiber, etc. As the inorganic filler, one or two or more of the above specific examples can be used in combination. As the inorganic filler, in the above specific examples, for example, it is preferable to use silicon dioxide. Thereby, the interaction between the inorganic filler and the adhesion assistant can further improve the adhesion.

In this embodiment, the lower limit value of the cumulative 50% particle diameter (D ₅₀ ) based on the volume of the filler is preferably 0.1 μm or more, more preferably 0.3 μm or more, and even more preferably 0.5 μm or more. This makes it possible to prevent clogging of the mold caused by agglomeration of the inorganic filler during the molding of the sealing resin composition, and to improve the productivity of the electronic device.
In addition, the upper limit of the cumulative 50% particle diameter (D ₅₀ ) of the volume basis of the inorganic filler is, for example, preferably 50 μm or less, more preferably 30 μm or less, more preferably 20 μm or less, and 10 μm or less. It is particularly preferable that it is less than 5 μm. Accordingly, in the sealing step, clogging in the mold can be reliably suppressed, and the productivity of the electronic device can be improved.
In addition, when manufacturing an electronic device with a small entering gap of a sealing resin composition such as a flip chip package, the sealing resin composition is a mold underfill material. At this time, the volume-based cumulative 50% particle diameter (D ₅₀ ) of the inorganic filler is preferably 1 μm or more and 20 μm or less, for example. Thereby, the filling property of the sealing resin composition can be improved.
The volume-based cumulative 50% particle diameter (D ₅₀ ) of the filler can be measured on a volume basis using a commercially available laser diffraction particle size distribution measurement device (for example, manufactured by Shimadzu Corporation, SALD-7000). Particle size distribution and calculation.

(Coupling agent)
The coupling agent is not limited, and a known coupling agent used for a sealing resin composition can be used.
Specific examples of the coupling agent include vinylsilanes such as vinyltrimethoxysilane and vinyltriethoxysilane; 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidyl Epoxy silanes such as oxypropyl triethoxy silane; styryl silanes such as p-styryl trimethoxy silane; 3-methacryloxypropyl methyl dimethoxy silane, 3-methyl propylene Methoxypropyltrimethoxysilane, such as methoxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. ; 3-propenyloxypropyltrimethoxysilane and other propenylsilylsilane; N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (amine Ethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilane-N- (1,3-dimethyl-butylene) propylamine, N-phenyl-3-amino Aminosilanes such as trimethoxysilane and phenylaminopropyltrimethoxysilane; trimeric isocyanates; alkylsilanes; ureidosilanes such as 3-ureidopropyltrialkoxysilane; 3- Mercaptosilanes such as mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; isocyanate silanes such as 3-isocyanatepropyltriethoxysilane; titanium compounds; aluminum chelates; aluminum / Zirconium-based compounds and the like. As the coupling agent, one or two or more of the specific examples described above can be blended.

(Release Agent)
The release agent is not limited, and a known release agent used for a sealing resin composition can be used.
Specific examples of the release agent include natural waxes such as palm wax, synthetic waxes such as diethanolamine and dimonate, higher fatty acids such as zinc stearate, metal salts thereof, and paraffin wax. As a mold release agent, 1 type, or 2 or more types can be mix | blended in the said specific example.

(Colorant)
The colorant is not limited, and a known colorant used for a sealing resin composition can be used.
Specific examples of the colorant include carbon black, red dandelion, and titanium oxide. As the colorant, one or two or more of the above specific examples can be blended.

(Flame retardant)
The flame retardant is not limited, and a known flame retardant used for a sealing resin composition can be used.
Specific examples of the flame retardant include aluminum hydroxide, magnesium hydroxide, zinc borate, zinc molybdate, and phosphazene. As a flame retardant, 1 type, or 2 or more types can be mix | blended in the said specific example.

(Ion trapping agent)
The ion trapping agent is not limited, and a known ion trapping agent for a resin composition for sealing can be used.
Specific examples of the ion trapping agent include hydrotalcite, zeolite, and bismuth hydroxide.

(Low stress agent)
The low-stress agent is not limited, and a known low-stress agent used for the sealing resin composition can be used.
Specific examples of the low stress agent include polysiloxane compounds such as polysiloxane oil and polysiloxane rubber; polybutadiene compounds; acrylonitrile-butadiene copolymers, and the like. As the low-stress agent, one or two or more of the above specific examples can be blended.

(Manufacturing method of sealing resin composition)
Next, the manufacturing method of the sealing resin composition of this embodiment is demonstrated.
The method for producing a sealing resin composition according to this embodiment includes, for example, a mixing step (S1) of mixing the above-mentioned raw material components to prepare a mixture, and a molding step (S2) followed by forming the mixture.

(Mixing step (S1))
The mixing step is a step of mixing raw material ingredients to prepare a mixture. The method of mixing is not limited, and a well-known method can be used according to the component used.
Specifically, as the mixing step, the raw material components included in the sealing resin composition are uniformly mixed using a mixer or the like. Next, the mixture is melt-kneaded with a kneader such as a roll, a kneader, or an extruder to prepare a mixture.

(Forming step (S2))
Following the mixing step (S1), a forming step (S2) of forming the mixture is performed.
The method of forming is not limited, and a known method can be used in accordance with the shape of the resin composition for sealing. The shape of the sealing resin composition is not limited, and examples thereof include a granular shape, a powder shape, an ingot shape, and a sheet shape. The shape of the sealing resin composition can be selected in accordance with the molding method.

Examples of the molding step for preparing the granular sealing resin composition include a step of pulverizing and cooling the mixture after melt-kneading. In addition, for example, a sealing resin composition formed into a particle shape may be screened to adjust the particle size. In addition, for example, the sealing resin composition formed into a pellet shape may be processed by a method such as a centrifugal milling method or a thermal cutting method to adjust the degree of dispersion or fluidity.
In addition, as a molding step for preparing a powdery sealing resin composition, for example, a step of pulverizing the mixture to obtain a granular sealing resin composition, and further pulverizing the granular sealing resin composition is exemplified. .
In addition, as a molding step for preparing the ingot-like sealing resin composition, for example, the mixture is pulverized to obtain a granular sealing resin composition, and then the granular sealing resin composition is ingot-molded. Steps of molding.
Moreover, as a shaping | molding process of producing a sheet-like sealing resin composition, the process of extruding or calendering a mixture after melt-kneading is mentioned, for example.

Next, the details of the manufacturing method of the electronic device of this embodiment are demonstrated.

(Manufacturing method of electronic device)
The manufacturing method of the electronic device according to this embodiment includes a coating step of forming an OSP film on a copper circuit by applying a front flux to the surface of a member having a copper circuit on the surface, and applying a sealing resin composition to the substrate. The copper circuit is sealed.
In addition, after the coating step and before the sealing step, the cleaning step of removing the OSP film is not performed.
In addition, after the coating step and before the sealing step, for example, a reflow step for performing soldering may be included.

(Coating step)
First, a coating step of forming an OSP film on a copper circuit by applying a front flux to the surface of a member having a copper circuit on the surface is performed. Thereby, in the manufacturing process of an electronic device, oxidation of a copper circuit can be suppressed. Therefore, the electrical reliability of the electronic device can be improved.
The method of applying the pre-flux is not limited, and examples thereof include a method of dipping a component including a copper circuit on a surface of a solution containing the pre-flux. At this time, the thickness of the OSP film can be adjusted by controlling the immersion time.
As described above, the OSP film has a complex layer composed of a complex of a front flux and a copper atom, for example. The OSP film may further include, for example, an imidazole layer formed of an imidazole compound in which the complex is not formed, in addition to the complex layer.

It does not limit as a member which has a copper circuit on the surface, For example, the board | substrate with which a copper circuit is arrange | positioned can be used.
Specific examples of the substrate of the present embodiment include wiring substrates such as a flexible printed circuit board, an interposer, and a lead frame.
The material for forming the substrate of this embodiment is not limited, and examples thereof include organic materials such as resins and inorganic materials such as ceramics.
In addition, the sealing resin composition according to this embodiment can exhibit better adhesion without removing the OSP film with respect to members containing copper, such as a copper pad on which an OSP film is formed, from this viewpoint. .

As the flux before this embodiment, an imidazole compound is used.
The imidazole compound is not limited as long as it is a conventionally known one used as a pre-flux, and for example, those represented by the following general formulae (I1) and (I2) can be used.

(In the above general formulae (I1) and (I2), a plurality of R ^I are each independently hydrogen or an organic group having 1 to 30 carbon atoms. The plurality of R ^I may be the same as or different from each other.)

In the general formulae (I1) and (I2), examples of the organic group having 1 to 30 carbon atoms in R ^I include methyl, ethyl, n-propyl, isopropyl, and n- Butyl, isobutyl, secondary butyl, tertiary butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl and other alkyl groups; phenyl, naphthyl, anthracenyl, etc. Aryl group; a halogen-substituted alkyl group in which one or more of the hydrogen atom of the alkyl group or the aryl group is substituted with a halogen atom;

Specific examples of the imidazole compound include imidazole, 2-methylimidazole, 2- (1-methylpentyl) imidazole, 2-ethyl-4-methylimidazole, 4-methylimidazole, and 2 , 4,5-trimethylimidazole, 4,5-dichloro-2-ethylimidazole, 2-methylbenzimidazole, 2-heptyl-5,6-dimethylbenzimidazole, 2-octyl Methyl-5-chlorobenzimidazole, 4-fluorobenzimidazole, 2-pentyl-5-iodobenzimidazole, 2,4-diphenylimidazole, 2- (2,4-diethyl) -4 -(3-propyl-5-octyl) -5-isobutylimidazole, 2-phenyl-4- (1-naphthyl) imidazole, 2- (1-naphthyl) -4-phenylimidazole, 2-phenylbenzimidazole, 2- (1-naphthyl) benzimidazole, 2-cyclohexylbenzimidazole and the like.
As the imidazole compound, one or two or more of the above specific examples can be used in combination.

The upper limit of the thickness of the OSP film formed by the coating step is, for example, 1.0 μm or less is preferred, 0.8 μm or less is more preferred, 0.6 μm or less is further preferred, and 0.4 μm or less is further preferred. 0.3 μm or less is particularly preferred. Thereby, in the sealing step, the OSP film is easily broken by the sealing resin composition, and the adhesion between the hardened material of the sealing resin composition and the copper circuit can be further improved.
In addition, the lower limit of the thickness of the OSP film formed by the coating step is, for example, preferably 0.05 μm or more, more preferably 0.08 μm or more, more preferably 0.10 μm or more, and more preferably 0.15 μm or more. good. This can further suppress oxidation of the copper circuit. Therefore, the electrical reliability of the electronic device can be improved. In addition, according to the method for manufacturing an electronic device according to this embodiment, even if the thickness of the OSP film is greater than or equal to the above-mentioned lower limit value, the OSP film can be destroyed without performing a washing step, and the cured resin composition for sealing and the copper circuit can be improved. The adhesion is better from this viewpoint.

(Sealing step)
After the coating step, a sealing step of sealing a copper circuit with a sealing resin composition is performed without performing a cleaning step of removing the OSP film. The sealing step can be performed by, for example, mold forming.

The method for mold forming is not limited, and specifically, transfer molding, compression moding, injection molding, and the like can be used. As a molding method when sealing is performed, a transfer molding method is preferably used in the above specific examples.

In this embodiment, the conditions for forming the mold are not limited. For example, it can be pre-cured by heat treatment at a temperature of 120 ° C to 200 ° C for 10 seconds to 30 minutes, and then at a temperature of 120 ° C to 200 ° C. Post-curing is performed by performing heat treatment for 1 hour to 24 hours.
In this embodiment, a post-cured sealing resin composition is shown as a cured product.

As the lower limit value of the mold forming temperature, for example, 100 ° C or higher is preferred, 110 ° C or higher is more preferred, 120 ° C or higher is further preferred, and 150 ° C or higher is further preferred. The higher the mold forming temperature, the easier it is to break the OSP film by the sealing resin composition. Thereby, the adhesiveness of the hardened | cured material of the sealing resin composition and a copper circuit can be improved.
The upper limit of the mold forming temperature may be, for example, 240 ° C or lower, and may be 220 ° C or lower.

(Washing step)
In the manufacturing method of the electronic device of this embodiment, the washing step of removing the OSP film is not performed after the coating step and before the sealing step. Thereby, it is preferable from a viewpoint that productivity of an electronic device can be improved.
In the conventional manufacturing method of an electronic device, the washing | cleaning process which removes an OSP film, for example is not performed. Thereby, there is room for improvement in the adhesion between the sealing resin composition and copper.
In addition, when it is necessary to remove the OSP film, as a cleaning step performed in a conventional method of manufacturing an electronic device, specifically, a chemical treatment using rubidium water may be mentioned. In order to remove the complex layer of the OSP film, as osmium water, specifically, adipic acid, azelaic acid, eicosenedioic acid, citric acid, glycolic acid, succinic acid, salicylic acid, and diethanol were used. Acid, 2,6-pyridinedicarboxylic acid, dibutylaniline diglycolic acid, suberic acid, sebacic acid, thioacetic acid, terephthalic acid, dodecanedioic acid, p-hydroxyphenylacetic acid, picolinic acid, benzeneamber Acid, phthalic acid, fumaric acid, maleic acid, malonic acid, lauric acid, benzoic acid, tartaric acid, tris (2-carboxyethyl) isocyanurate, glycine, 1,3 -Cyclohexanedicarboxylic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butanoic acid, 2,3-dihydroxybenzoic acid, 2,4-diethylpentane Diacid, 2-quinolinic acid, 3-hydroxybenzoic acid, malic acid, p-anisic acid, stearic acid, 12-hydroxystearic acid, oleic acid, linoleic acid, hypolinolenic acid, dimer acid, hydrogenation Organic acids such as dimer acid, trimer acid and hydrogenated trimer acid.
In addition, for example, the above-mentioned organic acid may be contained in the flux used at the time of soldering. Thereby, there is a part where the flux exists, and the OSP film around the solder is broken, and the residue of the flux can be removed by washing. However, the remaining OSP film other than the soldering periphery is the cause of the decrease in adhesion between the hardened material of the sealing material and the copper circuit.

(Reflow step)
In the manufacturing method of the electronic device according to this embodiment, after the coating step and before the sealing step, for example, a reflow step for performing soldering may be included.
In the reflow step, soldering is performed at, for example, a temperature of 180 ° C. to 300 ° C. The complex layer of the OSP film is strengthened by heat treatment in the reflow step. In the manufacturing method of the electronic device according to this embodiment, it is preferable that the complex layer can be destroyed by the sealing step even if the complex layer of the OSP film is made firm after the reflow step.

Next, the electronic device of this embodiment will be described.

(Electronic device)
The electronic device according to this embodiment is not limited, and specifically includes a printed wiring board, a molded circuit component (Molded Interconnect Device: MID), and the like.
Here, the printed wiring board is not limited. Specific examples include: MAP (Mold Array Package), QFP (Quad Flat Package), and SOP (Small Outline Package). Outline Package (CSP), Chip Size Package (CSP), Quad Flat Non-leaded Package (QFN), Small Outline Non-leaded Package (SON), Small Outline Non-leaded Package (SON), BGA (Ball Grid Array, Ball Grid Array Package), LF-BGA (Lead Flame BGA, Lead Frame Ball Grid Array Package), FCBGA (Flip Chip BGA, flip-chip ball grid array package), MAPBGA (Molded Array Process BGA, mold Array technology ball grid array package), eWLB (Embedded Wafer-Level BGA, embedded wafer level ball grid array package), Fan-In (fan-in) eWLB, Fan-Out (fan-out) eWLB and other semiconductor packages; SIP (System In package).
In addition, the molded circuit component is not limited, and specific examples thereof include those used in automotive components.

As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to the said embodiment, The structure can be changed within the range which does not change the meaning of this invention.
[Example]

Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited at all by the description of these examples.

First, the raw material components of the sealing resin composition will be described.

(Epoxy resin)
・ Epoxy resin 1: Biphenylaralkyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., NC3000)
・ Epoxy resin 2: a mixture of a triphenylmethane type epoxy resin and a biphenyl type epoxy resin (manufactured by Mitsubishi Chemical Corporation, YL6677)

(hardener)
・ Hardener 1: Biphenylaralkyl-type phenol resin (made by Meiwa Plastic Industries, Ltd., MEH-7851SS)
・ Hardener 2: Triphenylmethane type phenol resin (manufactured by AIR WATER INC., HE910-20)

(Adhesion aid)
・ Adhesion aid 1: γ-mercaptopropyltrimethoxysilane with thiol group (Chisso Corporation, S810)
・ Adhesion Aid 2: γ-mercaptopropyltriethoxysilane with thiol group (manufactured by Momentive Performance Materials Japan LLC, SILQUESTA-1891 SILANE)
・ Adhesion Aid 3: Stearic acid with carboxyl group (NOF CORPORATION, SR-SACRA)
-Adhesion Aid 4: 2,4-diamino-6- (4,5-dihydroxypentyl) -1,3,5-tri (terminated by SHIKOKU CHEMICALS CORPORATION) )
・ Adhesion aid 5: 3-amino-5-mercapto-1,2,4-triazole (Made by NIPPON CARBIDE INDUSTRIES CO., INC.) With thiol group, tertiary amine group, and heterocyclic amine group
The structural formulas of the adhesion promoters 1-5 are shown in the following formulas (A1) to (A5).

(Hardening accelerator)
・ Hardening accelerator 1: Synthesis of an adduct of a hafnium compound and a silane compound represented by the following formula (P1), and using it as a hardening accelerator 1. The synthesis method is described in detail below.
First, in a flask containing 1800 g of methanol, 249.5 g of phenyltrimethoxysilane and 384.0 g of 2,3-dihydroxynaphthalene were added and dissolved, and then stirred at room temperature and 28% sodium methoxide was added dropwise. -231.5 g of a methanol solution. Next, a solution prepared by dissolving 503.0 g of tetraphenylphosphonium bromide in 600 g of methanol was stirred at room temperature and dropped into a flask to precipitate crystals. The precipitated crystals were filtered, washed with water, and dried under vacuum to obtain a hardening accelerator 1 of powdery white crystals as an adduct of an amidine compound and a silane compound.

(Inorganic filler)
・ Inorganic filler 1: Fused spherical silica (manufactured by Lonson, MUF-46V, D ₅₀ = 4.3 μm)
・ Inorganic filler 2: Spherical fine powdered silica (manufactured by Admatechs Company Limited, SC-2500-SQ, D ₅₀ = 0.6 μm)
The volume-based cumulative 50% particle diameter (D ₅₀ ) of the filler was measured and calculated using a laser diffraction particle size distribution measurement device (manufactured by Shimadzu Corporation, SALD-7000) on a volume basis.

(Coupling agent)
・ Coupling agent 1: N-phenyl-3-aminopropyltrimethoxysilane (manufactured by Dow Corning Toray Co., Ltd., CF-4083)

(Release Agent)
・ Releasing agent 1: Diethanolamine ・ Dimonanate (manufactured by Itoh Oil Chemicals Co., Ltd., ITOHWAX TP NC 133)

(Colorant)
・ Colorant 1: Carbon black (manufactured by Mitsubishi Chemical Corporation, carbon # 5)

(Flame retardant)
・ Flame retardant 1: Aluminum hydroxide (manufactured by Sumitomo Chemical Company, Limited, CL-303)

(Ion trapping agent)
・ Ion trapping agent 1: Hydrotalcite (Kyowa Chemical Industry Co., Ltd., DHT-4H)

(Low stress agent)
・ Low stress agent 1: carboxy-terminated acrylonitrile-butadiene copolymer (manufactured by PTI Japan Corporation, CTBN1008SP)

(Example 1)
First, the components described in the blending amounts described in Table 1 below were mixed at room temperature using a mixer, and then heated and kneaded at a temperature of 70 ° C to 100 ° C. Next, after cooling to normal temperature, pulverization was performed to prepare a sealing resin composition used in the production of the electronic device of Example 1.
Next, a printed wiring board having a copper circuit on a surface having a length of 15 mm × width of 15 mm was prepared. Next, a flux containing a imidazole compound (GLICOAT-SMD F2 (LX) PK, manufactured by SHIKOKU CHEMICALS CORPORATION) was coated on the printed wiring board to form an OSP film having a thickness of 0.2 μm.
Next, a flip-chip package with a length of 10 mm × width of 10 mm × a thickness of 250 μm was placed on the printed wiring board, and then a solder bump was melted at a peak temperature of 240 ° C., a peak temperature time of 10 seconds, and a nitrogen atmosphere, thereby melting the solder bumps. To bond the flip-chip package to the printed wiring board. The reflow process was performed twice.
Next, the obtained substrate with the package mounted thereon was placed in a mold, and the above-mentioned sealing epoxy resin composition was injected into the mold using a transfer molding machine under conditions of a mold temperature of 175 ° C and an injection pressure of 9.8 MPa. Forming. Then, a hardening treatment was performed at 175 ° C for 120 seconds to produce an electronic device.

(Examples 2 to 6, Comparative Example 1)
An electronic device was produced in the same manner as in Example 1 except that the blending composition of the sealing resin composition was changed to those described in Examples 2 to 6 and Comparative Example 1 in Table 1 below.

(Cu adhesion)
For the electronic devices of Examples 1 to 6 and Comparative Example 1, the following experiments were performed in order to evaluate the adhesion between the sealing resin composition and the copper circuit.
First, a copper plate having a length of 10 mm × width of 30 mm × thickness of 0.2 mm was prepared to simulate a copper circuit. Next, a flux (a GLICOAT-SMD F2 (LX) PK manufactured by Shikoku Chemicals Corporation, manufactured by SHIKOKU CHEMICALS CORPORATION) containing an imidazole compound was applied to the copper plate to form an OSP film having a thickness of 0.2 μm.
Next, a heat treatment was performed at a peak temperature of 240 ° C, a peak temperature time of 10 seconds, and a simulated reflow process in a nitrogen environment. This heat treatment was performed twice.
Next, the copper plate on which the OSP film was formed was placed in a mold, and the seal used in the production of the electronic device of each example and comparative example 1 was sealed using a transfer molding machine under conditions of a mold temperature of 175 ° C and an injection pressure of 9.8 MPa. An epoxy resin composition was injected into the mold and molded. Then, a hardening treatment was performed at a temperature of 175 ° C for 120 seconds, and a hardened product of a cylindrical sealing resin composition having a bottom surface diameter of 3.6 mmφ and a height of 3 mm was produced on the copper plate on which the OSP film was formed. Thereby, ten test pieces in which a hardened material of a sealing resin composition was arranged on a copper plate on which an OSP film was formed were produced.
Ten test pieces using the resin composition for sealing of the electronic device of each Example and Comparative Example 1 were tested at a temperature of 260 ° C using an automatic wafer cutting measurement device (manufactured by Nordson Advanced Technology (Japan) KK, DAGE4000 type) The shear adhesive force for the adhesion between the sealing resin composition and the copper plate was evaluated. The average value of the shear adhesive force of the ten test pieces is shown in Table 1 below as Cu adhesion. The unit is "N / mm".

[Table 1]

As shown in Table 1, it was confirmed that the electronic device manufactured by the electronic device manufacturing method of each example has higher Cu adhesion than the electronic device manufactured by the electronic device manufacturing method of Comparative Example 1.

This application claims priority on the basis of Japanese Patent Application No. 2017-247284, filed on December 25, 2017, the entire disclosure of which is hereby incorporated by reference.

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Claims (13)

A method for manufacturing an electronic device includes the following steps: Steps to prepare components with copper circuits on the surface; A coating step of forming an OSP film on the copper circuit by applying a pre-flux on the surface; and A sealing step of sealing the copper circuit with a sealing resin composition, The sealing step is performed without performing a cleaning step of removing the OSP film formed in the coating step, The sealing resin composition includes an epoxy resin, a hardener, and an adhesion assistant. The pre-flux contains an imidazole compound. For example, the method for manufacturing an electronic device according to the first claim, wherein the adhesion assistant comprises one or more members selected from the group consisting of a thiol group, a carboxyl group, and an amine group. For example, the manufacturing method of an electronic device according to the second item of the patent application, wherein the adhesion assistant contains the amine group, The amine group contains a heterocyclic amine group. For example, the method for manufacturing an electronic device according to the first patent application range, wherein the content of the adhesion assistant in the sealing resin composition is 0.010 parts by mass or more and 1.0 part by mass relative to the total solid content of the sealing resin composition. the following. For example, the method for manufacturing an electronic device according to claim 1 in which the content of the adhesion promoter in the sealing resin composition is 0.10 parts by mass or more and 10 parts by mass relative to the total amount of the epoxy resin and the hardener. The following. For example, the method for manufacturing an electronic device according to the first claim, wherein the sealing resin composition further includes an inorganic filler, The inorganic filler contains silicon dioxide. For example, the method for manufacturing an electronic device according to item 6 of the application, wherein the volume-based cumulative 50% particle diameter D ₅₀ of the inorganic filler is 0.1 μm or more and 50 μm or less. For example, the method for manufacturing an electronic device according to claim 1, wherein the hardener includes a phenol resin-based hardener. For example, in the method for manufacturing an electronic device according to claim 1, in the coating step, the thickness of the OSP film is 0.05 μm or more and 1.0 μm or less. For example, the method for manufacturing an electronic device according to the first patent application range, wherein the sealing step is performed by mold forming. For example, in the method for manufacturing an electronic device according to claim 10, in the sealing step, the temperature of the mold forming is 100 ° C. or higher and 240 ° C. or lower. For example, in the method for manufacturing an electronic device according to claim 10, in the sealing step, the mold forming method is one selected from the group consisting of a transfer mold forming method, a compression molding method, and an injection molding method. . For example, the manufacturing method of an electronic device according to item 1 of the patent application scope, wherein the electronic device is a printed wiring board or a molded circuit component (Molded Interconnect Device: MID).