JP2012197379A - Method for manufacturing adhesive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an adhesive film in which the dispersion efficiency of an inorganic filler is excellent and the generation of faults in an adhesive layer is suppressed.SOLUTION: The method for manufacturing an adhesive film includes: a first mixing step of mixing a silica filler and a solvent under reduced pressure to obtain a first mixture; a dispersion step of dispersing the first mixture or a second mixture to obtain a dispersion; a first filtration step of filtering the dispersion to obtain a filtration residue; a vanish preparation step of obtaining a vanish for an adhesive layer by using the residue; and an adhesive layer formation step of coating the vanish for an adhesive layer on a substrate to form an adhesive layer.

Description

  The present invention relates to a method for producing an adhesive film.

  In recent years, there has been a rapid increase in demands for multifunctional and lightweight and compact mobile related devices. Accordingly, the need for high-density mounting of semiconductor elements is increasing year by year, and the development of a stacked multi-chip package (hereinafter referred to as “stacked MCP”) in which semiconductor elements are stacked plays a central role.

  The technical development of stacked MCP is to achieve both conflicting goals of package miniaturization and multi-stage loading. For this reason, the thickness of silicon wafers used for semiconductor elements has been rapidly reduced, and wafers with a thickness of 100 μm or less are being actively used and studied. In addition, since the multi-stage loading causes the package production process to become complicated, there is a need for a production process and material proposal corresponding to the simplification of the package production process and the increase in the number of wire bonding thermal histories by multi-stage loading.

  Under such circumstances, a paste material has been conventionally used as an adhesive member of the stacked MCP. However, the paste material has a problem that the resin protrudes in the bonding process of the semiconductor element and the film thickness accuracy is low. Since these problems cause problems during wire bonding and voids in the paste agent, the use of paste materials has made it impossible to cope with the above requirements.

  In recent years, in order to improve such a problem, a film-like adhesive has been used instead of the paste material. Compared to paste materials, film adhesives can control the amount of protrusion in the bonding process of semiconductor elements, and increase film thickness accuracy to reduce film thickness variation. Therefore, application to a stacked MCP is being actively studied.

  This film-like adhesive usually has a configuration in which an adhesive layer is formed on a release substrate, and one of typical usage methods is a wafer back surface application method. The wafer back surface attaching method is a method of directly attaching a film adhesive to the back surface of a silicon wafer used for manufacturing a semiconductor element. In this method, after a film adhesive is applied to a semiconductor wafer, the release substrate is removed, and a dicing tape is applied on the adhesive layer. Thereafter, the wafer is mounted on the wafer ring, and the wafer is cut into a desired semiconductor element size together with the adhesive layer. The semiconductor element after dicing has a structure having an adhesive layer cut out to the same size on the back surface. The semiconductor element with the adhesive layer is picked up and attached to a substrate to be mounted by a method such as thermocompression bonding. wear.

  Various studies have been made on the adhesive layer constituting the film adhesive as described above. For example, it is often configured to include an inorganic filler (filler) in addition to the adhesive resin component (for example, , See Patent Document 1).

JP 2001-302998 A

  With the thinning of the silicon wafer as described above, the demand for thinning the film adhesive is also increasing. However, in thinning a film adhesive containing an inorganic filler in addition to an adhesive component, defects due to the inorganic filler may occur on the film surface due to poor dispersion of the inorganic filler. Such defects on the film surface may cause cracking of the silicon wafer when bonded to a thinned silicon wafer.

  The present invention has been made in view of the above, and it is an object of the present invention to provide an adhesive film manufacturing method in which the efficiency of the inorganic filler dispersion process can be improved and the occurrence of defects in the adhesive layer is suppressed. .

Specific means for solving the above problems are as follows.
<1> A first mixing step in which an inorganic filler and a solvent are mixed under reduced pressure to obtain a first mixture, and the first mixture and an adhesive component are mixed to obtain a second mixture. 2 mixing step, a dispersion step of dispersing the first mixture or the second mixture to obtain a dispersion, a first filtration step of filtering the dispersion to obtain a filtrate, and the filtration A varnish preparation step for obtaining an adhesive layer varnish using a product, and an adhesive layer formation step for forming the adhesive layer by applying the adhesive layer varnish on a base material, to produce an adhesive film Method.

<2> The method for producing an adhesive film according to <1>, wherein the adhesive layer has a thickness of 20 μm or less.

<3> The method for producing an adhesive film according to <1> or <2>, wherein the second mixing step is performed under reduced pressure.

<4> The varnish preparation step includes a third mixing step in which the filtrate and the thermoplastic resin are mixed to obtain a third mixture, and the third mixture is filtered to obtain an adhesive layer varnish. The manufacturing method of the adhesive film of any one of said <1>-<3> including a 2nd filtration process.

  ADVANTAGE OF THE INVENTION According to this invention, efficiency improvement of the dispersion | distribution process of an inorganic filler can be achieved, and the manufacturing method of the adhesive film in which generation | occurrence | production of the defect in an adhesive bond layer was suppressed can be provided.

In the present invention, the term “process” is not limited to an independent process, and is included in the term if the intended action of the process is achieved even when it cannot be clearly distinguished from other processes.
In the present specification, numerical ranges indicated using “to” indicate ranges including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.

  The method for producing an adhesive film of the present invention comprises a first mixing step of mixing an inorganic filler and a solvent under reduced pressure to obtain a first mixture, the first mixture, and an adhesive component. A second mixing step for obtaining a second mixture, a dispersion step for dispersing the second mixture to obtain a dispersion, and a first filtration step for obtaining a filtrate by filtering the dispersion. And an adhesive layer forming step of applying the adhesive layer varnish produced using the filtered material on a substrate to form an adhesive layer, and including other steps as necessary. Composed.

By performing the first mixing step under reduced pressure, fine bubbles attached to the surface of the inorganic filler (filler) are efficiently removed, and the wettability of the inorganic filler to the solvent is improved. The dispersibility of the inorganic filler in the dispersing treatment is improved, and the generation of aggregates is also suppressed. This suppresses occurrence of problems such as clogging in the distributed processing, and further reduces the time required for the distributed processing. Moreover, the filterability in the filtration process after a dispersion process becomes favorable, the clogging of a filtration filter is suppressed, and the productivity of adhesive film manufacture improves.
In addition, since the inorganic filler is uniformly and finely dispersed, generation of defects in the adhesive layer of the manufactured adhesive film is suppressed, and generation of cracks in the silicon wafer due to the defects is suppressed. Furthermore, by performing the first mixing step under reduced pressure, the effect is maintained in the subsequent steps, and the occurrence of defects in the adhesive layer is suppressed.

(First mixing step)
The reduced pressure in the first mixing step is not particularly limited as long as the inside of the container used for mixing is in a reduced pressure state lower than atmospheric pressure, but from the viewpoint of dispersion efficiency, it is preferably 30 kPa or less, and 15 kPa or less. More preferably.

As a method for reducing the pressure, a normally performed pressure reducing method can be used without particular limitation. For example, a vacuum pump can be connected to a depressurizable container (for example, a closed mixing kettle) that performs the first mixing step, and the air in the container can be sucked to reduce the pressure.
Further, the method for adjusting the reduced pressure state is not particularly limited. For example, adjusting the vacuum state by adjusting the suction force of the vacuum pump or adjusting the amount of leakage from a leak valve, etc. so that the pressure gauge connected to the container becomes a desired pressure reduction state Can do.

In the first mixing step, the inorganic filler and the solvent are mixed. Details of the inorganic filler and the solvent will be described later. The mixing method in the first mixing step is not particularly limited as long as it can be performed under reduced pressure, and can be performed by a usual mixing method.
For example, a solvent and an inorganic filler can be put into a container with a stirrer that can be depressurized, and the mixing process can be performed under a reduced pressure by the stirrer.
Examples of the mixing apparatus that can perform the mixing treatment under reduced pressure include Max Blend manufactured by Sumitomo Heavy Industries, Ltd.

The conditions for the mixing treatment can be appropriately selected according to the mixing method. For example, the mixing time can be 1 to 20 hours, and preferably 1 to 12 hours. As mixing temperature, it can be set to 0-40 degreeC, and it is preferable that it is 10-30 degreeC.
Moreover, when mixing by stirring, it can be set as stirring speed 20-120 rpm using stirring blades, such as a saddle type and a propeller type.

  In the present invention, prior to the first mixing step performed under reduced pressure, a step of mixing the solvent and the inorganic filler under normal pressure may be further provided. By further providing a mixing step under normal pressure, scattering of the inorganic filler can be suppressed, and productivity is further improved.

  The mixing ratio of the inorganic filler and the solvent in the first mixing step is not particularly limited, but from the viewpoint of dispersion efficiency, the content of the inorganic filler is 5 to 20% by mass in the total amount of the inorganic filler and the solvent. Is preferable, and it is more preferable that it is 10-15 mass%.

In the first mixing step, the inorganic filler and the solvent are mixed, but other components may be added as necessary.
In the first mixing step, ultrasonic treatment can be used in combination. Dispersion efficiency is further improved by using ultrasonic treatment in combination with the mixing treatment.

(Second mixing step)
In the second mixing step, the first mixture obtained in the first mixing step or the dispersion obtained by dispersing the first mixture is mixed with the adhesive component.
The second mixing step is preferably a step of mixing the dispersion obtained by dispersing the first mixture and the adhesive component.
Details of the adhesive component used in the second mixing step will be described later. Further, the second mixing step may be a step of mixing together with other components other than the adhesive component. Examples of other components include a thermoplastic resin described later.

  The mixing method in the second mixing step is not particularly limited as long as the first mixture or the dispersion thereof and the adhesive component can be mixed, and a commonly used mixing method can be appropriately selected and used. For example, the mixing method described in the first mixing step can also be adopted in the second mixing method, and the preferred embodiments are also the same.

In the present invention, the second mixing step may be performed under normal pressure or under reduced pressure, but it is preferably performed under reduced pressure from the viewpoint of dispersion efficiency. By performing the second mixing step under reduced pressure in addition to the first mixing step, the dispersion efficiency is more effectively improved.
The reduced pressure state in the second mixing step and its preferred mode are the same as the reduced pressure state in the first mixing step.

(Dispersion process)
In the dispersion step, the first mixture obtained in the first mixing step or the second mixture obtained in the second mixing step is subjected to dispersion treatment. By performing the dispersion treatment, the inorganic filler is uniformly and finely dispersed in the solvent, and the occurrence of defects is effectively suppressed when the adhesive layer is formed.

  The method for distributed processing is not particularly limited, and a commonly used distributed processing method can be appropriately selected and used. Specifically, for example, the dispersion treatment can be performed using a rough machine, a three roll, a ball mill, a bead mill, or the like. Among these, from the viewpoint of dispersion efficiency, it is preferable to perform dispersion treatment using a bead mill.

  The beads used in the bead mill are not particularly limited, and examples thereof include alumina beads and zirconia beads. Moreover, as a particle size of a bead, it can be set as 0.1 mm-3 mm, for example, and it is preferable that it is 0.1 mm-1 mm.

  The conditions for the distributed processing are appropriately selected according to the distributed processing method. For example, when using a bead mill, it can be 10 to 30 hours at a peripheral speed of 1 to 10 m / sec and a speed of 1 to 3 L / min. In addition, the dispersion treatment is preferably performed by cooling to 40 ° C. or lower in order to suppress an increase in the liquid temperature.

(First filtration step)
In the first filtration step, the dispersion obtained in the dispersion step is filtered. The filtration treatment can be performed, for example, by applying pressure to the dispersion and passing through the filtration filter.
In the present invention, since the first mixing step is performed under reduced pressure, the filtration efficiency can be improved, the occurrence of clogging of the filter can be suppressed, and the productivity of the adhesive film can be improved. .

The material of the filtration filter is not particularly limited, and can be appropriately selected from commercially available filtration filters. For example, a micro screen manufactured by Sumitomo 3M may be used.
The filter performance (pore diameter) of the filtration filter is not particularly limited, and can be, for example, 1 μm to 20 μm, and preferably 1 μm to 10 μm.
The filtration pressure in the filtration treatment is not particularly limited, and can be, for example, 0.01 to 0.3 MPa, and preferably 0.01 to 0.2 MPa.

  The filtrate obtained in the first filtration step can be used as it is with the adhesive layer varnish, or can be further added with other additives as necessary to form an adhesive layer varnish.

(Third mixing step)
In the present invention, after the first filtration step, it is preferable to provide a third mixing step of mixing the filtrate obtained in the filtration step with a thermoplastic resin to obtain a third mixture. By mixing the thermoplastic resin after the first filtration step, the dispersion efficiency in the dispersion step is improved.

In the third mixing step, the filtrate and the thermoplastic resin are mixed. Details of the thermoplastic resin will be described later.
Moreover, the mixing method in the third mixing step is the same as the first mixing method, and the preferred embodiment is also the same.

Furthermore, the third mixing step is preferably performed under reduced pressure. Thereby, generation | occurrence | production of the clogging of the filter in the 2nd filtration process mentioned later is suppressed more, and also generation | occurrence | production of the defect at the time of forming an adhesive bond layer is suppressed more effectively.
The reduced pressure state in the third mixing step is the same as the reduced pressure state in the first mixing step, and the preferred embodiment is also the same.

(Second filtration step)
In this invention, it is preferable to provide the 2nd filtration process which obtains the varnish for adhesive bond layers by filtering the obtained 3rd mixture after the said 3rd mixing process. Generation | occurrence | production of the defect at the time of forming an adhesive bond layer by filtering a 3rd mixture is suppressed more effectively.
The filtration treatment in the second filtration step is the same as the filtration treatment in the first filtration step, and the preferred embodiment is also the same.

(Adhesive layer forming process)
In the adhesive layer forming step, the adhesive layer varnish obtained as described above is applied onto a substrate to form an adhesive layer.
The adhesive layer varnish may be subjected to a defoaming treatment or the like before being applied. Examples of the defoaming treatment include vacuum defoaming treatment, ultrasonic defoaming treatment, and standing.

  The base material serves as a carrier film when the adhesive film is used. Examples of such base materials include polyester films such as polyethylene terephthalate films, polytetrafluoroethylene films, polyethylene films, polypropylene films, polymethylpentene films, polyolefin films such as polyvinyl acetate films, polyvinyl chloride films, and polyimide films. A plastic film or the like can be used. Moreover, paper, a nonwoven fabric, metal foil, etc. can also be used.

  Further, the surface of the substrate that is in contact with the adhesive layer may be surface-treated with a release agent such as a silicone release agent, a fluorine release agent, or a long-chain alkyl acrylate release agent.

  Although the thickness of a base material can be suitably selected in the range which does not impair the workability | operativity at the time of use, it is preferable that it is 10-500 micrometers, it is more preferable that it is 25-100 micrometers, and it is 30-50 micrometers. Is particularly preferred.

  As a method of applying the adhesive layer varnish on the substrate, a known application method can be used. For example, a knife coating method, a roll coating method, a spray coating method, a gravure coating method, a bar coating method, a curtain coating method, or the like can be used.

The coating layer formed by coating the adhesive layer varnish on the substrate can be formed into an adhesive layer by removing at least a part of the solvent contained in the coating layer. The method for removing the solvent is not particularly limited, and a known method such as heating or decompression can be appropriately selected.
In the present invention, the amount of the solvent remaining in the adhesive layer is not particularly limited, but is preferably 5% by mass or less, and more preferably 3% by mass or less with respect to the adhesive layer.

The thickness of the adhesive layer formed in the adhesive layer forming step is not particularly limited, but is preferably 100 μm or less, and more preferably 20 μm or less.
Although the adhesive layer tends to be thinned in response to the recent trend of thinning silicon wafers, the first mixing step is performed under reduced pressure, so that defects can be generated in the thinned adhesive layer. It can be effectively suppressed.

  The adhesive layer varnish constituting the adhesive layer contains at least one inorganic filler (filler), at least one solvent, and at least one adhesive component, and is optionally thermoplastic. A resin, a coupling agent, an ion scavenger and the like are included.

(Inorganic filler)
The adhesive layer varnish includes at least one inorganic filler (filler). By including the inorganic filler, the handleability and thermal conductivity of the formed adhesive layer are improved. In addition, it is possible to adjust melt viscosity and impart thixotropic properties.
The inorganic filler (filler) is not particularly limited. For example, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, Examples thereof include aluminum borate whisker, boron nitride, crystalline silica, and amorphous silica.

Among these, aluminum oxide, aluminum nitride, boron nitride, crystalline silica, and amorphous silica are preferable from the viewpoint of improving thermal conductivity. From the viewpoint of adjusting melt viscosity and imparting thixotropic properties, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, crystallinity Silica and amorphous silica are preferred.
In the present invention, it is preferable to use at least one silica filler selected from crystalline silica and amorphous silica as the inorganic filler.

Further, the shape of the inorganic filler is not particularly limited.
Furthermore, the particle diameter of the inorganic filler is not particularly limited, but the average primary particle diameter is preferably 10 nm to 1 μm, and more preferably 20 nm to 50 nm.
These inorganic fillers can be used singly or in combination of two or more.

  The addition amount of the inorganic filler is preferably 1 to 20% by mass based on the total amount of the adhesive layer. The addition effect is sufficiently obtained when the addition amount is 1 mass or more. Moreover, by being 20 mass% or less, it can suppress that the adhesiveness of an adhesive bond layer falls, or an electrical property falls by void remaining etc.

(solvent)
The adhesive layer varnish contains at least one solvent. The solvent is not particularly limited. For example, alcohol solvents such as methanol, ethanol, 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol; ketone solvents such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone; aromatic solvents such as toluene and xylene Amide solvents such as dimethylacetamide, dimethylformamide, N-methylpyrrolidone and the like.

  Considering volatility during film production, for example, methanol, ethanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, methyl ethyl ketone, acetone, methyl isobutyl ketone, toluene, xylene and the like having relatively low boiling points It is preferable to use a solvent.

For the purpose of improving the coating properties, it is also preferable to use a solvent having a relatively high boiling point such as dimethylacetamide, dimethylformamide, N-methylpyrrolidone and cyclohexanone.
In the present invention, a ketone solvent is preferably used from the viewpoint of dispersion efficiency and the like.
These solvents can be used alone or in combination of two or more.

(Adhesive component)
Examples of the adhesive component in the present invention include a thermosetting adhesive component, a photocurable adhesive component, a thermoplastic adhesive component, and an oxygen-reactive adhesive component. These can be used alone or in combination of two or more, but considering that they are used for fixing semiconductor elements as an adhesive, the adhesive component may be composed of a thermosetting adhesive component. preferable.

The thermosetting adhesive component is not particularly limited as long as it is cured by heat, and has a functional group such as a glycidyl group, an acryloyl group, a methacryloyl group, a hydroxyl group, a carboxyl group, an isocyanurate group, an amino group or an amide group. A compound containing a thermopolymerizable component may be mentioned.
These can be used singly or in combination of two or more, but considering the heat resistance as an adhesive film and the adhesive force due to thermosetting, use a thermosetting resin that cures by heat and exerts an adhesive action. It is preferable.

  Examples of the thermosetting resin include an epoxy resin, an acrylic resin, a silicone resin, a phenol resin, a thermosetting polyimide resin, a polyurethane resin, a melamine resin, and a urea resin, and in particular, heat resistance, workability, and reliability. It is most preferable to use an epoxy resin in terms of obtaining an adhesive film excellent in the resistance. When using an epoxy resin as the thermosetting resin, it is preferable to use an epoxy resin curing agent together.

  The epoxy resin is not particularly limited as long as it is cured and has an adhesive action. For example, a bifunctional epoxy resin such as a bisphenol A type epoxy resin, a novolak such as a phenol novolac type epoxy resin or a cresol novolac type epoxy resin. A type epoxy resin or the like can be used. Moreover, what is generally known, such as a polyfunctional epoxy resin, a glycidyl amine type epoxy resin, a heterocyclic ring-containing epoxy resin, or an alicyclic epoxy resin, can be used. These can be used alone or in combination of two or more.

  As the epoxy resin, for example, as bisphenol A type epoxy resin, Epicoat series (Epicoat 807, Epicoat 815, Epicoat 825, Epicoat 827, Epicoat 828, Epicoat 834, Epicoat 1001, Epicoat 1004, manufactured by Japan Epoxy Resin Co., Ltd. Epicoat 1007, Epicoat 1009), DER-330, DER-301, DER-361 manufactured by Dow Chemical Company, YD8125, YDF8170 manufactured by Toto Kasei Co., Ltd., and the like. Examples of the phenol novolac type epoxy resin include Epicoat 152 and Epicoat 154 manufactured by Japan Epoxy Resin Co., Ltd., EPPN-201 manufactured by Nippon Kayaku Co., Ltd., DEN-438 manufactured by Dow Chemical Company, and the like. Furthermore, as the o-cresol novolak type epoxy resin, EOCN-102S, EOCN-103S, EOCN-104S, EOCN-1012, EOCN-1025, EOCN-1027, manufactured by Nippon Kayaku Co., Ltd., manufactured by Toto Kasei Co., Ltd. YDCN701, YDCN702, YDCN703, YDCN704 and the like.

  As the polyfunctional epoxy resin, Epon 1031S manufactured by Japan Epoxy Resin Co., Ltd., Araldite 0163 manufactured by BASF Japan, Denacol EX-611, EX-614, EX-614B, EX-622 manufactured by Nagase ChemteX Corporation. , EX-512, EX-521, EX-421, EX-411, EX-321, and the like.

When using an epoxy resin as an adhesive component, it is preferable to use an epoxy resin curing agent. As the epoxy resin curing agent, known curing agents that are usually used can be used, for example, amines, polyamides, acid anhydrides, polysulfides, boron trifluoride, dicyandiamide, bisphenol A, bisphenol F, bisphenol. Examples thereof include bisphenols having two or more phenolic hydroxyl groups in one molecule such as S, phenol resins such as phenol novolac resin, bisphenol A novolac resin or cresol novolac resin.
Among these, phenol resins such as phenol novolak resin, bisphenol A novolak resin, and cresol novolak resin are preferable in terms of excellent electric corrosion resistance at the time of moisture absorption. These epoxy resin curing agents can be used alone or in combination of two or more.

  Preferred examples of the phenol resin curing agent include, for example, trade names: Phenolite LF2882, Phenolite LF2822, Phenolite TD-2090, Phenolite TD-2149, Phenolite, manufactured by Dainippon Ink & Chemicals, Inc. VH-4150, Phenolite VH4170, Meiwa Kasei Co., Ltd., trade name: H-1, Japan Epoxy Resin Co., Ltd., trade name: EpiCure MP402FPY, EpiCure YL6065, EpiCure YLH129B65, and Mitsui Chemicals, Inc. Product names: Mirex XL, Mirex XLC, Mirex RN, Mirex RS, Mirex VR, and the like.

The content of the adhesive component contained in the adhesive layer varnish is not particularly limited. For example, the adhesive layer varnish is preferably contained in an amount of 8 to 12% by mass, and preferably 9 to 11% by mass. More preferred.
When the adhesive component contains an epoxy resin and a phenol resin curing agent, the content ratio of the epoxy resin and the phenol resin curing agent (epoxy resin / phenol resin curing agent) is, for example, 0.8 on the basis of epoxy equivalent. It can be set to 1.2 or more and preferably 0.9 or more and 1.1 or less.

  When the adhesive component contains a thermosetting adhesive component, a curing accelerator may be further added to the adhesive layer varnish. There is no restriction | limiting in particular as a hardening accelerator, For example, imidazole etc. are mentioned. Specific examples include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, and the like. Or in combination of two or more.

  5 mass parts or less are preferable with respect to 100 mass parts of total amounts of a thermosetting adhesive component, and, as for the addition amount of this hardening accelerator, 3 mass parts or less are more preferable. When this addition amount exceeds 5 parts by mass, the storage stability tends to decrease.

(Thermoplastic resin)
The adhesive layer varnish in the present invention preferably contains at least one thermoplastic resin.
The thermoplastic resin is not particularly limited as long as it is a thermoplastic resin, or at least a resin that has thermoplasticity in an uncured state and forms a crosslinked structure after heating, but is not limited to thermoplastic resin (A) Tg (glass transition (Temperature) is 10 to 100 ° C. and the weight average molecular weight is 5000 to 200000, or the thermoplastic resin (B) Tg is −50 ° C. to 10 ° C., and the weight average molecular weight is preferably 100,000 or more. .

  As the former thermoplastic resin (A), for example, polyimide resin, polyamide resin, polyetherimide resin, polyamideimide resin, polyester resin, polyesterimide resin, phenoxy resin, polysulfone resin, polyethersulfone resin, polyphenylene sulfide resin, Examples include polyether ketone resins. Among these, it is preferable to use a polyimide resin.

  As the latter thermoplastic resin (B), it is preferable to use a polymer containing a structural unit derived from a functional monomer. Examples of the functional group of the functional monomer of the polymer include a glycidyl group, an acryloyl group, a methacryloyl group, a hydroxyl group, a carboxyl group, an isocyanurate group, an amino group, and an amide group, and among them, a glycidyl group is preferable. More specifically, a glycidyl group-containing (meth) acrylic copolymer containing a structural unit derived from a functional monomer such as glycidyl acrylate or glycidyl methacrylate is preferable, and is incompatible with a thermosetting resin such as an epoxy resin. More preferably.

  Examples of the polymer containing a structural unit derived from the functional monomer include a glycidyl group containing a structural unit derived from a functional monomer such as glycidyl acrylate or glycidyl methacrylate and having a weight average molecular weight of 100,000 or more. Examples include (meth) acrylic copolymers, and among them, those that are incompatible with the epoxy resin are preferable. Specific examples of the glycidyl group-containing (meth) acrylic copolymer include HTR-860P-3 (trade name) manufactured by Nagase ChemteX Corporation.

The adhesive film produced by the production method of the present invention is one in which an adhesive layer is provided on a substrate, but if necessary, on the surface opposite to the surface facing the substrate of the adhesive layer A protective film may be provided.
Examples of the protective film include a polyethylene film.

  In addition, an adhesive layer (dicing tape) may be provided on the surface of the adhesive film opposite to the surface facing the substrate of the adhesive layer to constitute a die bond dicing sheet. The die bond dicing sheet is described, for example, in JP-A-7-45557.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

<Example 1>
Using a container equipped with a stirrer and capable of decompression (made by Daisho Heating Co., Ltd.) as a mixing kettle, to 640 parts by mass of cyclohexanone, 100 parts by mass of silica filler (R972 average primary particle size 20 nm, manufactured by Nippon Aerosil Co., Ltd.) Under reduced pressure (1 kPa), the mixture was stirred and mixed at a stirring speed of 70 rpm for 1 hour to obtain a first mixture (first mixing step).
To the obtained first mixture, 16 parts by mass of YDCN-703 (trade name, manufactured by Toto Kasei Co., Ltd., cresol novolac type epoxy resin, epoxy equivalent 210) as an epoxy resin, and Millex XLC-LL (product) as a phenol resin Name, Mitsui Chemicals Co., Ltd., phenol resin) 13 parts by mass was added and stirred and mixed at a stirring speed of 60 rpm for 5 hours under normal pressure to obtain a second mixture (second mixing step).

A dispersion was prepared by subjecting the obtained second mixture to a dispersion treatment for 20 hours using a bead mill (zirconia beads, particle size: 0.15 mm) (dispersing step).
The obtained dispersion was subjected to a filtration treatment at a filtration pressure of 0.15 MPa using a filter having a filter performance of 10 μm to obtain a filtrate (first filtration step).

To the obtained filtrate, 250 parts by mass of HTR-860-P3 (trade name, manufactured by Nagase ChemteX Corporation, epoxy group-containing acrylic copolymer), and Curazole 2PZ-CN (trade name) as a curing accelerator. , Shikoku Kasei Co., Ltd., 1-cyanoethyl-2-phenylimidazole) was added, and the mixture was stirred and mixed under normal pressure at a stirring speed of 60 rpm for 5 hours to obtain a third mixture (third). Mixing step).
Next, using a filter having a filter performance of 10 μm, a filtration treatment was performed at a filtration pressure of 0.15 MPa to prepare an adhesive layer varnish (second filtration step).

  The adhesive layer varnish obtained above was applied to a 50 μm-thick polyethylene terephthalate film (trade name: Teijin Purex A31, manufactured by Teijin DuPont Films, Ltd.) as a release substrate using a comma coater. did. Heat drying was performed at 140 ° C. for 5 minutes to form an adhesive layer in a B-stage state with a film thickness of 20 μm to produce an adhesive film.

<Evaluation>
(Filter life)
Filtration treatment until the initial filtration rate is reduced to half the filter life of each filtration filter used in the first filtration step and the second filtration step by repeating the above adhesive film production method a plurality of times. Evaluated by the number of times.
The evaluation results are shown in Table 1.

(Clogging failure)
The above adhesive film manufacturing method was repeated a predetermined number of times, and clogging defects were evaluated as an average value of the number of times clogging defects occurred in the dispersion step.
The evaluation results are shown in Table 1.

(Film defect)
The surface of the obtained adhesive film was observed using a CCD camera, and the type and number of occurrences of film defects were evaluated by image analysis software. The types of film defects were classified into two types: granular defects caused by the filler itself, and repellent defects that are thought to occur with the filler as a nucleus. In addition, the number of occurrences of defects was evaluated as a defect reduction rate (%) based on the total number of occurrences of granular defects and repelling defects per 1000 m of the adhesive film and based on the total number of occurrences in Comparative Example 1 described later. The evaluation results are shown in Table 1.

<Example 2>
In Example 1, an adhesive film was produced in the same manner as in Example 1 except that the second mixing step was performed under reduced pressure (1 kPa). Evaluation was performed in the same manner as described above. The evaluation results are shown in Table 1.

<Example 3>
In Example 1, an adhesive film was produced in the same manner as in Example 1 except that the second mixing process and the third mixing process were performed under reduced pressure (1 kPa). Evaluation was performed in the same manner as described above. The evaluation results are shown in Table 1.

<Comparative Example 1>
In Example 1, an adhesive film was produced in the same manner as in Example 1 except that the first mixing step was performed under normal pressure. Evaluation was performed in the same manner as described above. The evaluation results are shown in Table 1.

<Comparative example 2>
In Example 1, an adhesive film was produced in the same manner as in Example 1 except that the first mixing step was performed under normal pressure and the second mixing step was performed under reduced pressure (1 kPa). Evaluation was performed in the same manner as described above. The evaluation results are shown in Table 1.

<Comparative Example 3>
In Example 1, an adhesive film was produced in the same manner as in Example 1 except that the first mixing step was performed under normal pressure and the third mixing step was performed under reduced pressure (1 kPa). Evaluation was performed in the same manner as described above. The evaluation results are shown in Table 1.

<Comparative example 4>
In Example 1, the adhesive film was the same as Example 1 except that the first mixing step was performed under normal pressure, and the second mixing step and the third mixing step were each performed under reduced pressure (1 kPa). Manufactured. Evaluation was performed in the same manner as described above. The evaluation results are shown in Table 1.

From Table 1, by producing an adhesive film by the method for producing an adhesive film of the present invention, the filter life in the filtration process can be improved, the occurrence of clogging defects in the dispersion treatment can be suppressed, and the productivity is improved. I understand that
Furthermore, it turns out that generation | occurrence | production of the defect in an adhesive bond layer can be suppressed by the defect reduction rate of 2 times or more.

Claims (4)

A first mixing step of mixing the inorganic filler and the solvent under reduced pressure to obtain a first mixture;
A second mixing step of mixing the first mixture and an adhesive component to obtain a second mixture;
A dispersion step of dispersing the first mixture or the second mixture to obtain a dispersion;
A first filtration step of filtering the dispersion to obtain a filtrate;
A varnish preparation step for obtaining an adhesive layer varnish using the filtrate,
An adhesive layer forming step of applying the adhesive layer varnish on a substrate to form an adhesive layer; and
The manufacturing method of the adhesive film containing this.   The manufacturing method of the adhesive film of Claim 1 whose thickness of the said adhesive bond layer is 20 micrometers or less.   The method for producing an adhesive film according to claim 1 or 2, wherein the second mixing step is performed under reduced pressure. The varnish preparation step includes
A third mixing step of mixing the filtrate and the thermoplastic resin to obtain a third mixture;
A second filtration step of filtering the third mixture to obtain an adhesive layer varnish;
The manufacturing method of the adhesive film of any one of Claims 1-3 containing this.