JP2016182701A - Method and apparatus for producing film material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for producing a film material having a small coefficient of thermal expansion with good productivity.SOLUTION: There is provided a method for producing a film material 10 which comprises: a first preparation step of preparing a substrate 1; a second preparation step of preparing a first raw material liquid containing a first resin and a first solvent used as raw materials for fibers; a third preparation step of preparing a second raw material liquid containing a thermosetting second resin 2R and a second solvent; a fiber deposition step of producing fibers 2F containing the first resin from the raw material liquid by spraying the raw material liquid on the substrate 1 to deposit fibers 2F on the substrate 1; a resin coating step of coating the second raw material liquid on the substrate 1; and a drying step of removing the second solvent contained in the coated second raw material liquid, wherein the coefficient of linear expansion CF of the first resin is smaller than the coefficient of linear expansion CR of the second resin 2R in a cured state.SELECTED DRAWING: Figure 2A

Description

  The present invention relates to a film material manufacturing method and manufacturing apparatus, and more particularly to a method and apparatus for manufacturing a film material having a low coefficient of thermal expansion.

  As a method for mounting a circuit member having a large number of connection parts on another circuit member, a wire bonding method and a flip chip method are widely used. Among these, the flip chip method has been attracting attention because it allows fine pitch connection and makes it possible to reduce the weight and thickness of electronic devices.

  As the flip chip method, circuit members are connected by solder bumps, and both are sealed with an underfill material, both are connected via a conductive adhesive (Patent Document 1, etc.), ACF ( There are a method of joining and connecting the two via an anisotropic conductive film), a method of joining the two using NCF (Non-conductive Film), and connecting the two using solder bumps. In particular, a method using a film material such as ACF or NCF as a bonding material is useful because the manufacturing process is simple.

  In addition, when a circuit member such as a separated semiconductor chip is picked up and bonded to another circuit member serving as a support, a film-like adhesive called a die bond film may be used (Patent Document 2). .

JP 2008-69316 A JP 2003-261833 A

  As the resin constituting the ACF, NCF, die bond film, and the like, a thermosetting resin such as an epoxy resin is usually used. Therefore, thermocompression bonding is used for joining circuit members. For example, a silicon semiconductor chip is bonded to a glass epoxy substrate by thermocompression bonding through a film layer containing a thermosetting resin to manufacture a mounting structure. However, in the cooling process after thermocompression bonding, the mounting structure may be warped or the circuit members may be separated from the film layer. This is because each material has a different coefficient of thermal expansion. When materials having different linear expansion coefficients are used in combination, and heating and cooling are performed, thermal stress is generated due to a difference in thermal expansion coefficient. Thermal stress tends to concentrate at the interface between the materials, particularly at the end of the interface.

  Thermosetting resins generally have a much larger linear expansion coefficient than silicon and glass epoxy substrates. The linear expansion coefficient of the thermosetting resin can be several tens of times that of silicon, for example. The linear expansion coefficient of the thermosetting resin can be several times that of the glass epoxy substrate, for example.

  Therefore, it is conceivable to use a resin called engineering plastic or super engineering plastic (hereinafter also referred to as engineering plastic) having a small linear expansion coefficient together with the thermosetting resin. By using engineering plastics, the thermal expansion coefficient of the entire film layer is expected to be small.

  For example, in order to form an epoxy resin into a film, a method (solution casting method) in which the epoxy resin is dissolved in an organic solvent, this solution is cast on a substrate, and the organic solvent is removed is generally used. However, resins having a small linear expansion coefficient such as engineering plastics are generally difficult to dissolve in general-purpose organic solvents used for dissolving other resins (for example, epoxy resins). Therefore, the homogeneity of the obtained film is lowered, and the bonding property between circuit members is lowered.

  In order to increase the homogeneity of the film, it is conceivable to use an organic solvent (for example, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, etc.) that dissolves the engineering plastic. However, these organic solvents have a high boiling point. Therefore, when these organic solvents are used as the material for the film layer, a drying process must be performed at a high temperature in order to remove the organic solvent. This drying process causes a problem that the curing of the epoxy resin proceeds.

  Moreover, the latent hardening agent which coat | covered the hardening component with the polymer may be used as a hardening | curing agent of an epoxy resin. However, the organic solvent that dissolves the engineering plastic as described above causes a problem that the polymer that coats the curing component is dissolved and the curing of the epoxy resin proceeds before the film is formed.

  One aspect of the present invention includes a first preparation step for preparing a base material, a second preparation step for preparing a first raw material liquid containing a first resin and a first solvent, which are fiber raw materials, and a thermosetting first. A third preparatory step of preparing a second raw material liquid containing two resins and a second solvent; and a fiber containing the first resin from the first raw material liquid by injecting the first raw material liquid on the substrate. A fiber deposition step for generating and depositing the fibers on the base material; a resin coating step for coating the base material with the second raw material liquid; and the coated second raw material liquid And a drying step for removing the second solvent, wherein the linear expansion coefficient CF of the first resin is smaller than the linear expansion coefficient CR of the cured second resin.

  Another aspect of the present invention includes a base material supply unit that supplies a base material to a transport belt, and a first resin that includes a first resin and a first solvent that serve as a raw material for fibers above the transported base material. The fiber containing the first resin is generated from the raw material liquid, the generated fiber is deposited on the base material, and the thermosetting second resin and the surface of the base material to be conveyed A film material obtained by removing the second solvent contained in the second raw material liquid coated on the substrate to be transported and the resin coating part for coating the second raw material liquid containing the second solvent And a recovery unit that scrapes off the film material fed from the drying unit, and the linear expansion coefficient CF of the first resin is a linear expansion coefficient of the second resin in a cured state The present invention relates to a film material manufacturing apparatus smaller than CR.

  According to the present invention, a film material having a low coefficient of thermal expansion can be manufactured with high productivity.

It is a figure for demonstrating a fiber deposition process among the manufacturing methods which concern on one Embodiment of this invention. It is a figure for demonstrating the resin coating process among the manufacturing methods which concern on one Embodiment of this invention. It is a figure for demonstrating a drying process among the manufacturing methods which concern on one Embodiment of this invention. It is a figure for demonstrating the manufacturing method which concerns on other one Embodiment of this invention. It is a figure for demonstrating the manufacturing method which concerns on other one Embodiment of this invention. It is a figure for demonstrating the manufacturing method which concerns on other one Embodiment of this invention. It is sectional drawing which shows typically one Embodiment of the film material obtained by the manufacturing method of this invention. It is sectional drawing which shows typically other one Embodiment of the film material obtained by the manufacturing method of this invention. It is sectional drawing which shows typically other one Embodiment of the film material obtained by the manufacturing method of this invention. It is sectional drawing which shows typically other one Embodiment of the film material obtained by the manufacturing method of this invention. It is sectional drawing which shows typically other one Embodiment of the film material obtained by the manufacturing method of this invention. It is a figure for demonstrating the manufacturing apparatus which concerns on one Embodiment of this invention. It is a figure for demonstrating the manufacturing apparatus which concerns on other one Embodiment of this invention. It is a figure for demonstrating the manufacturing apparatus which concerns on other one Embodiment of this invention.

  The manufacturing method of the film material which concerns on this invention is the 1st preparatory process which prepares a base material, the 2nd preparatory process which prepares the 1st raw material liquid containing the 1st resin and 1st solvent used as the raw material of a fiber, A third preparation step of preparing a second raw material liquid containing a curable second resin and a second solvent, and a fiber containing the first resin from the first raw material liquid by injecting the first raw material liquid on the substrate A fiber deposition step for generating and depositing fibers on the base material, a resin coating step for coating the base material with the second raw material liquid, and drying for removing the second solvent contained in the coated second raw material liquid And a process. At this time, the linear expansion coefficient CF of the first resin is smaller than the linear expansion coefficient CR of the cured second resin. Thereby, the film material which has a film layer with a small coefficient of thermal expansion can be manufactured with high productivity. Examples of the film material include ACF, NCF, and die bond film.

  The resin coating process may be performed between the fiber deposition process and the drying process. This is because the second resin penetrates between the fibers and the adhesion between the fibers and the second resin is improved. Moreover, since many 2nd raw material liquids are arrange | positioned on the outer surface of a film layer precursor, a 2nd solvent is easy to be removed.

  The fiber deposition process may be performed between the resin coating process and the drying process. Also in this case, the second resin penetrates between the fibers, and the adhesion between the fibers and the second resin is improved.

  The drying process may be performed between the resin coating process and the fiber deposition process. In this case, since the fiber produced | generated on a base material becomes difficult to embed or immerse in 2nd resin, the volume ratio of the fiber of the surface on the opposite side to the base material of a film layer can be increased.

  The fiber deposition step is preferably performed by an electrospinning method. This is because productivity is further improved.

  Furthermore, it is preferable that a fiber deposition process, a resin coating process, and a drying process are continuously performed with respect to the conveyed base material including the conveyance process of conveying a base material. Productivity is further improved by producing a film material by a so-called roll-to-roll process.

  The diameter of the deposited fiber is preferably 1 μm or less. This is because when the film layer is used as a bonding material for bonding between circuit members, the flow of the second resin is hardly inhibited during thermocompression bonding.

  The second raw material liquid preferably further contains a conductive material. Thereby, the obtained film material can be used as a film-like conductive adhesive for connection between circuit members having electrodes facing each other. In this case, when the diameter of the deposited fiber is 1 μm or less, the conductive material can easily move.

  The apparatus for producing a film according to the present invention includes a base material supply unit that supplies a base material to a transport belt, and a first raw material that includes a first resin and a first solvent that are raw materials for fibers above the transported base material. A fiber containing a first resin is produced from the liquid, and a fiber-forming part for depositing the produced fiber on the base material, and a thermosetting second resin and a second solvent on the surface of the base material to be conveyed 2 From the resin coating part that coats the raw material liquid, the drying part that forms the film material by removing the second solvent contained in the second raw material liquid coated on the substrate to be transported, and the drying part And a recovery unit that scrapes off the film material to be sent out. At this time, the linear expansion coefficient CF of the first resin is smaller than the linear expansion coefficient CR of the cured second resin. Thereby, the film material which has a film layer with a small coefficient of thermal expansion can be manufactured with high productivity.

  The resin coating part may be arranged between the fiber forming part and the drying part. Moreover, the fiber formation part may be arrange | positioned between the resin coating part and the drying part. Furthermore, the drying part may be arrange | positioned between the resin coating part and the fiber formation part.

[Production method]
(1-1st Embodiment)
Hereinafter, the first to first embodiments of the manufacturing method according to the present invention will be described with reference to FIGS. In the first to first embodiments, the resin coating process is performed between the fiber deposition process and the drying process. 1A to 1C are views for explaining a film material manufacturing method according to an embodiment of the present invention. FIG. 2A is a diagram for explaining a manufacturing method in the case where the steps shown in FIGS. 1A to 1C are continuously performed. 3A and 3B are cross-sectional views schematically showing different embodiments of film materials obtained by the production method of the present invention.

  1B, 1C, and 2A, for convenience, the fiber 2F and the second raw material liquid 40 (or the thermosetting resin 2R) are shown as being laminated in a single layer form on the substrate 1. However, it is not limited to this. The fiber 2F may be partly or entirely embedded or immersed in the second raw material liquid 40 (or thermosetting resin 2R). According to this embodiment, the volume ratio of the fibers 2F on the substrate 1 side of the film layer 2 to be formed can be larger than the volume ratio of the fibers 2F on the opposite side. The configuration of the film material will be described later.

(1) First, Second and Third Preparation Steps First, the base material 1, the first raw material liquid 30 containing the first resin 2Fa and the first solvent as the raw material of the fiber 2F, the thermosetting second resin, and A second raw material liquid 40 containing a second solvent is prepared.

  The substrate 1 is a support that supports the film layer 2. The 1st raw material liquid 30 and the 2nd raw material liquid 40 are the raw materials of the film layer 2 which comprises the film material 10 (refer FIG. 3A and 3B). When the film material 10 is used as a bonding material for bonding circuit members (for example, ACF, NCF, die-bonding film, etc.), the film layer 2 is thermally transferred to one circuit member (hereinafter sometimes referred to as a transfer target). Then, the substrate 1 is peeled off.

  The film layer 2 is an uncured or semi-cured state with the fibrous first resin (fiber 2F) and is solidified at room temperature (for example, 20 to 35 ° C.) (thermosetting) Resin 2R). The semi-cured state is a state in which fluidity has been lost although it is not completely cured. Solidifying means a state in which the fluidity has been lost. For example, as described later, when the second raw material liquid 40 is applied onto a substrate, the second solvent contained in the second raw material liquid 40 is used. Is partially or completely removed.

[Base material]
The material of the base material 1 is not specifically limited, For example, a resin sheet, a paper sheet, a cloth sheet, a glass fiber sheet etc. can be used. Among these, a resin sheet is preferable from the viewpoint of handleability. As the resin constituting the resin sheet, polypropylene, polyethylene, polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, or the like) can be used. Among these, polyethylene terephthalate is preferable from the viewpoints of dimensional stability, solvent resistance, and cost. Although the thickness of the base material 1 is not specifically limited, It is preferable that it is 10-100 micrometers, and it is more preferable that it is 20-50 micrometers.

  From the viewpoint of transferability, the substrate 1 is preferably coated with a release agent on the surface facing the film layer 2. Examples of the release agent include silicone resins and fluorine compounds.

[First raw material liquid]
The first raw material liquid 30 includes a first resin 2Fa and a first solvent. The first resin 2Fa is dissolved in the first solvent. The first resin 2Fa (fiber 2F) formed in a fiber shape has a linear expansion coefficient CF smaller than the linear expansion coefficient CR of the cured thermosetting resin 2R (hereinafter simply referred to as “linear expansion coefficient CR”). .

  The linear expansion coefficient is measured using, for example, a thermal mechanical analysis device (Thermal Mechanical Analysis: TMA). Specifically, the film layer 2 is overlapped so as to have a predetermined thickness (for example, 0.5 mm), and cut into a predetermined length and width (for example, length 30 mm × width 5 mm) to prepare a sample. Both ends in the longitudinal direction of the obtained sample are each chucked with a pulling jig, and a load is applied so that the sample does not deform while the temperature is raised at a constant temperature. The amount of elongation of the sample at this time is measured.

The fiber 2F is not particularly limited as long as it has a linear expansion coefficient CF smaller than the linear expansion coefficient CR. Especially, an engineering plastic is preferably used for the 1st resin 2Fa which is a raw material of the fiber 2F at a heat resistant point. Engineering plastics are generally considered to be resins having a tensile strength of 500 kg / cm ² or more, have a low coefficient of thermal expansion, and are excellent in strength, impact resistance, heat resistance, and the like. Engineering plastics include, for example, polyamide (PA), polyacetal (POM), polycarbonate (PC), polyetheretherketone (PEEK), polyamideimide (PAI), polysulfone (PSF), polyethersulfone (PES), polyphenylene sulfide. (PPS), polytetrafluoroethylene (PTFE), polyarylate (PAR), polyetherimide (PEI), polyimide (PI) and the like. You may use these individually or in combination of 2 or more types. Among these, the first resin 2Fa is preferably PES in that it is suitable for the electrospinning method.

  The linear expansion coefficient CF of the fiber 2F is not particularly limited as long as it is smaller than the linear expansion coefficient CR. Especially, it is preferable that the linear expansion coefficient CF is 20-70 ppm / degreeC from the point of connection reliability.

  The first solvent is not particularly limited as long as it can dissolve the first resin 2Fa. Examples of the first solvent include N-methyl-2-pyrrolidone (boiling point 202 ° C.), N, N-dimethylformamide (boiling point 153 ° C.), N, N-dimethylacetamide (DMAc, boiling point 165 ° C.), cyclohexanone (boiling point 156). ° C). These may be used alone or in combination of two or more. The mixing ratio of the first solvent and the first resin 2Fa in the first raw material liquid 30 differs depending on the type of the first solvent selected and the type of the first resin 2Fa. The ratio of the 1st solvent in the 1st raw material liquid 30 is 60 mass% to 95 mass%, for example. The first raw material liquid 30 may contain a solvent other than the first solvent, various additives, and the like.

[Second raw material liquid]
The second raw material liquid 40 includes a thermosetting resin 2R and a second solvent. The thermosetting resin 2R is preferably dissolved in the second solvent.

  The thermosetting resin 2R is not particularly limited, and may include, for example, an epoxy resin, an acrylic resin, a polyimide, a phenol resin, a silicone resin, a melamine resin, a urea resin, an alkyd resin, a polyurethane, and an unsaturated polyester as a main agent. These may be used alone or in combination of two or more. Among these, an epoxy resin is preferable in terms of handleability.

  Examples of the epoxy resin include bisphenol A type epoxy resin, phenol novolac type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, glycidylamine type epoxy resin, and alicyclic type. Examples thereof include an epoxy resin, a dicyclopentadiene type epoxy resin, a polyether type epoxy resin, and a silicone-modified epoxy resin. Of these, bisphenol A-type epoxy resins are preferred in terms of bondability. The epoxy resin may be liquid or solid at room temperature.

  The second raw material liquid 40 further includes a curing agent and a curing accelerator. When the thermosetting resin 2R is an epoxy resin, for example, an acid anhydride or an amine compound is used as a curing agent. As the curing accelerator, imidazole accelerators, phosphorus curing accelerators, phosphonium salt curing accelerators, bicyclic amidines, organometallic complexes, polyamine ureas and the like are used. The second raw material liquid 40 may contain a solvent other than the second solvent, various additives, and the like.

  Although linear expansion coefficient CR is not specifically limited, For example, it is preferable that it is 30-80 ppm / degrees C. Moreover, it is preferable that the glass transition point Tg of the thermosetting resin 2R of a hardening state is 100-150 degreeC at the point of connection reliability. The glass transition point Tg is measured by the DMA method under measurement conditions of a temperature rise temperature of 2 ° C./min and a frequency of 1 Hz (hereinafter the same).

  The cured thermosetting resin 2R is a second resin in which the thermosetting resin 2R is cured with a curing agent and a curing accelerator, and includes the thermosetting resin 2R, the curing agent, and the curing accelerator. Yes. In other words, the cured thermosetting resin 2R occupies a portion of the film layer 2 excluding the conductive material 3 when the fibers 2F and the conductive material described later are included.

  The second solvent is not particularly limited, but preferably has a boiling point lower than the curing temperature of the thermosetting resin 2R. Examples of the second solvent include toluene (boiling point 110 ° C.), hexane (boiling point 69 ° C.), ethyl acetate (boiling point 77 ° C.), methyl ethyl ketone (boiling point 80 ° C.), and the like. You may use these individually or in combination of 2 or more types.

  The second raw material liquid 40 may further contain a conductive material. Thereby, the film material 10 can be used as a film-like conductive adhesive like ACF for connecting circuit members facing each other.

  Examples of the conductive material 3 include silver particles, solder particles, particles obtained by metal plating on insulating spherical particles, and nickel particles. Examples of the metal used for metal plating include gold, silver, nickel-phosphorus alloy, and palladium. Spherical particles include inorganic materials such as silica, heat-resistant resins such as polyurethane resin, epoxy resin, phenol resin, melamine resin, polyamide, polyimide, silicone resin, fluororesin, polyester, polyphenylene sulfide, and polyphenylene ether. Is mentioned. Among these, solder particles are preferable in terms of conductivity.

  Although content of the electroconductive material 3 is not specifically limited, It is preferable that 1-10 volume% is contained in the 2nd raw material liquid 40 from a viewpoint of joining property and electroconductivity. Further, when the conductive material 3 is in the form of particles, the average particle diameter D50 is not particularly limited. Especially, it is preferable that it is 1-10 micrometers from a conductive viewpoint between circuit members, and it is more preferable that it is 2-5 micrometers. The average particle diameter D50 is a median diameter in a volume particle size distribution determined by a laser diffraction particle size distribution measuring device (hereinafter the same).

(2) Fiber Deposition Step Next, as shown in FIG. 1A, fibers 2F are deposited on the main surface of the substrate 1. The fibers 2F are sprayed onto the substrate 1 by a dry spinning method or an electrospinning method in which the first raw material liquid 30 containing the first resin 2Fa is sprayed on the substrate 1 and the fibers 2F are formed while vaporizing the first solvent. Is deposited. Especially, it is preferable that the fiber 2F is formed by an electrospinning method in that a fiber having a small fiber diameter can be formed. According to the electrospinning method, the fibers 2F are deposited on the base material 1 in the form of a nonwoven fabric that is an aggregate of fibers in which one or more fibers 2F are randomly overlapped (or entangled).

  In many cases, the first solvent has a high boiling point in order to dissolve the first resin 2Fa such as engineering plastic. However, according to the above method, the first solvent is volatilized by heat or an electric field between the time when the first raw material liquid 30 is sprayed and the time when the fibers 2F are deposited on the substrate 1, and the Hardly remains. Therefore, in the manufacturing process of the film material 10, the process of removing the first solvent is not particularly necessary. Therefore, the curing of the thermosetting resin 2R hardly proceeds in the manufacturing process of the film material 10. As a result, when the film material 10 is used as a bonding material for bonding circuit members, the adhesion between the film layer 2 and the circuit member is not impaired in the thermal transfer process to the circuit members, and the bonding property between the circuit members is improved. .

  The fiber diameter of the fiber 2F is preferably less than 1 μm, more preferably less than 800 nm, and particularly preferably less than 600 nm. The fiber diameter of the fiber 2F is preferably 10 nm or more, more preferably 50 nm or more, and particularly preferably 200 nm or more. This is because the flow of the thermosetting resin 2R is difficult to be hindered in thermocompression bonding when the film layer is used as a bonding material for bonding between circuit members. Furthermore, if the fiber diameter of the fiber 2F is within this range, the flexibility is excellent. When the 2nd raw material liquid 40 contains the particulate conductive material 3, it is preferable that the fiber diameter of the fiber 2F is smaller than the average particle diameter D50 of the conductive material 3. This is because the movement of the conductive material 3 is hardly hindered by the fibers 2F, and it is easy to ensure the conductivity when the bonding material is used.

  Here, the fiber diameter is the diameter of the fiber. The diameter of the fiber is a diameter of a cross section perpendicular to the length direction of the fiber. If such a cross section is not circular, the maximum diameter may be considered as the diameter. Moreover, you may regard the width | variety of the direction perpendicular | vertical to the length direction of the fiber 2F when it sees from the normal line direction of one main surface of the film material 10 as the diameter of the fiber 2F.

Mass per unit area of the fiber 2F, from the viewpoint of heat resistance of the film layer 2 is preferably 0.05-5 g / m ^2, and more preferably 0.1 to 1 g / m ^2.

  After the fiber deposition step and before the resin coating step, a protective sheet (not shown) for suppressing scattering and cutting of the fibers 2F may be bonded to the base material 1 so as to sandwich the fibers 2F. The protective sheet is not particularly limited, and for example, a sheet made of polyethylene terephthalate or the like is used. Thereafter, the substrate 1 on which the protective sheet is laminated may be temporarily collected (for example, wound on a reel). The protective sheet is removed before the resin coating process. When the fiber deposition step and the resin coating step are performed continuously, the protective sheet can be omitted.

(3) Resin coating process Subsequently, as shown to FIG. 1B, the 2nd raw material liquid 40 is applied to the main surface on which the fiber 2F of the base material 1 was deposited. The coating method is not particularly limited, and examples thereof include a micro gravure method, a slot die coating method, and a knife coating method. FIG. 1B shows a state in which the second raw material liquid 40 is being discharged from the nozzle 44.

  The second raw material liquid 40 is applied so as to cover the fibers 2F deposited on the substrate 1. The coated second raw material liquid 40 penetrates into the gaps between the fibers 2F, and part or all of the fibers 2F are buried or immersed in the second raw material liquid 40. Therefore, the adhesion between the fiber 2F and the thermosetting resin 2R is good. Therefore, even if the softening points of the fiber 2F and the thermosetting resin 2F are different, the separation between the fiber 2F and the thermosetting resin 2R is suppressed during thermal transfer.

  The thickness of the film layer precursor 2a formed by application of the second raw material liquid 40 is not particularly limited as long as the thickness T of the film layer 2 after removing the second solvent is in the range of 5 to 100 μm. The thickness T is more preferably 10 to 30 μm. When the thickness T of the film layer 2 is within this range, the flexibility of the film layer 2 is improved, and the thickness of an electronic component using this as a bonding material can be reduced. The thickness T is a distance between the two main surfaces of the film layer 2.

(4) Drying step Finally, as shown in FIG. 1C, the film layer 2 is formed by removing a part or all of the second solvent contained in the formed film layer precursor 2a, and the film material 10 Is obtained. The removal of the second solvent can be performed by heat drying using hot air or drying under reduced pressure. Among these, it is preferable to use heat drying in terms of simplicity. FIG. 1C shows a case where heat drying is performed with warm air 51.

  The drying temperature is not particularly limited as long as the second solvent is removed and the thermosetting resin 2R is not cured. What is necessary is just to set a drying temperature suitably according to the kind of 2nd solvent and thermosetting resin 2R. For example, when toluene and ethyl acetate are used as the second solvent and an epoxy resin is used as the thermosetting resin 2R, the drying temperature is about 70 to 80 ° C. As described above, the removal of the second solvent is performed under relatively mild conditions. However, since the 2nd raw material liquid 40 exists abundantly on the outer surface of the film layer precursor 2a, it is easy to dry. Thereby, the thermosetting resin 2R is in an uncured or semi-cured state and is included in the film layer 2 in a solidified state.

  In order to suppress blocking, a protective sheet (not shown) may be laminated on the film material 10. The protective sheet is not particularly limited, and for example, a sheet made of polyethylene terephthalate or the like is used. When the film material 10 is a long body, the film material 10 may be wound up by a roll after that. The wound film material is cut into a predetermined shape and size and thermally transferred to a transfer target (for example, a circuit member).

  When the conveyance process which conveys the base material 1 is included, as shown to FIG. 2A, a fiber deposition process, a resin coating process, and a drying process may be continuously performed with respect to the base material 1 conveyed. preferable. Thereby, since the film material can be manufactured without collecting the substrate (for example, winding on a reel, etc.) during the fiber deposition process, the resin coating process, and the drying process, the productivity is further improved. In addition, space for manufacturing equipment can be saved. In FIG. 2A, the case where the base material 1 is a long body is shown. Specifically, the fibers 2F are deposited on the base material 1 while the base material 1 is conveyed in the direction D. The second raw material liquid 40 is subsequently applied while the substrate 1 on which the fibers 2F are deposited is conveyed as it is. Further, the film material 10A or 10B (see FIGS. 3A and 3B) is obtained by drying while being conveyed.

(1-2 embodiment)
The first to second embodiments are the same as the first to first embodiments except that the fiber deposition step is performed between the resin coating step and the drying step. Drawing 2B is a figure explaining a manufacturing method in case a resin coating process, a fiber deposition process, and a drying process are performed in this order continuously. 3C and 3D are cross-sectional views schematically showing different embodiments of the film material obtained by the production method of the present invention.

  In FIG. 2B, for the sake of convenience, the thermosetting resin 2R and the fibers 2F are shown as being laminated in a single layer form on the substrate 1, but the present invention is not limited to this. Some or all of the fibers 2F may be buried or immersed in the thermosetting resin 2R. According to this embodiment, the volume ratio of the fibers 2F on the substrate 1 side of the film layer 2 to be formed can be smaller than the volume ratio of the fibers 2F on the opposite side. The configuration of the film material will be described later.

  Also in this embodiment, when the conveyance process which conveys the base material 1 is included, as shown to FIG. 2B, a resin coating process, a fiber deposition process, and a drying process are continuous with respect to the base material 1 conveyed. It is preferable to be carried out automatically. In FIG. 2B, the case where the base material 1 is a long body is shown. Specifically, the second raw material liquid 40 is applied while the substrate 1 is conveyed in the direction D. The fiber 2F is continuously deposited on the base material 1 while the base material 1 coated with the second raw material liquid 40 is conveyed as it is. Furthermore, the film material 10C or 10D (refer FIG. 3C and 3D) is obtained by drying while conveying.

(1-3 embodiment)
The 1-3 embodiment is the same as the 1-1 embodiment, except that the drying process is performed between the resin coating process and the fiber deposition process. FIG. 2C is a diagram for explaining a manufacturing method in a case where the resin coating step, the drying step, and the fiber deposition step are successively performed in this order. FIG. 3E is a cross-sectional view schematically showing one embodiment of a film material obtained by the production method of the present invention.

  According to this embodiment, the fibers 2F are hardly buried in the thermosetting resin 2R and are deposited above the thermosetting resin 2R. Therefore, the volume ratio of the fibers 2F on the substrate 1 side of the film layer 2 to be formed is extremely smaller than the volume ratio of the fibers 2F on the opposite side. The configuration of the film material will be described later.

  Also in this embodiment, when the conveyance process which conveys the base material 1 is included, as shown to FIG. 2C, a resin coating process, a drying process, and a fiber deposition process are continuous with respect to the base material 1 conveyed. It is preferable to be carried out automatically. In FIG. 2C, the case where the base material 1 is a long body is shown. Specifically, after the base material 1 is conveyed in the direction D, the second raw material liquid 40 is applied and then dried. Next, the film material 10E (see FIG. 3E) is obtained by depositing the fibers 2F on the base material 1 while transporting the base material 1 as it is.

[Film material]
Next, an embodiment of the film material according to the present invention will be described with reference to FIGS.
The film materials 10 </ b> A to 10 </ b> E manufactured by any one of the above methods include the base material 1 and the film layer 2 disposed on one main surface of the base material 1. The film layer 2 includes an uncured or semi-cured thermosetting resin 2R and a fibrous first resin (fiber 2F). The fiber 2F has a linear expansion coefficient CF smaller than the linear expansion coefficient CR.

  Therefore, in the process where the circuit members are laminated and cooled after thermocompression bonding, the thermal expansion coefficient of the entire film layer 2 is smaller than when the thermosetting resin 2R is included alone. As a result, thermal stress caused by the difference in coefficient of thermal expansion with the circuit member is reduced, and peeling at the interface between the circuit member and the film layer is suppressed. In addition, the warpage of the electronic component is reduced.

  In the illustrated film materials 10A to 10E, the volume ratio of the fibers 2F has a gradient in one direction in the thickness direction of the film layer 2, but the present invention is not limited to this. The fibers 2F may be uniformly arranged inside the film layer 2, or are inclined so that the volume ratio of the fibers 2F increases toward the center of the film layer 2 or toward the outside. May be.

(Film materials 10A and 10B)
3A, when the thickness of the film layer 2 is T, the volume ratio VF1 _0.5 of the fibers 2F in the region from the surface on the base material 1 side of the film layer 2 to 0.5T is from the other surface of the film layer 2. The film material 10A larger than the volume ratio VF2 _0.5 of 2F fibers in the region up to 0.5T is shown. Hereinafter, the region from the surface on the base material 1 side of the film layer 2 to the predetermined position is referred to as a first region, and the remaining region (the region other than the first region including the other surface of the film layer 2) is the first region. This is referred to as two regions.

3B shows that the volume ratio VF1 _0.15 of the fibers 2F in the first region from the surface on the base material 1 side of the film layer 2 to 0.15T is the volume ratio VF2 of the fibers 2F in the remaining region (second region). _The film material 10B larger than _0.85 is shown.

  The volume ratio of the fibers 2F is obtained by taking a photograph of a cross section perpendicular to the main surface of the film material 10, and obtaining the areas of the fibers 2F included in the first region and the second region of the film layer 2, respectively. This can be determined by dividing by the area of the first region or the second region of the film layer 2, respectively. The area of the fiber 2F can be calculated by specifying the portion occupied by the fiber 2F, for example, by binarizing the captured image.

  The film materials 10A and 10B are useful when the linear expansion coefficients of the first circuit member and the second circuit member joined by the film material 10 are different. That is, by laminating a circuit member having a smaller linear expansion coefficient so that the first region of the film layer 2 is opposed, the difference in thermal expansion coefficient between each circuit member and the film layer is reduced, and the thermal stress is further increased. Decrease.

  From the viewpoint of peelability from the substrate 1 of the film layer 2, the volume ratio VF1 of the fibers 2F in the first region of the film layer 2 may be larger than the volume ratio VF2 of the fibers 2F in the second region of the film layer 2. preferable. At this time, the volume ratio VF1 is preferably 0.1 to 0.5, and more preferably 0.1 to 0.4. The volume ratio VF2 is preferably 0 to 0.1, and more preferably 0 to 0.05, from the viewpoint of adhesion.

  The volume ratio VF of the fibers 2F with respect to the entire film layer 2 is preferably 0.01 to 0.5, and more preferably 0.04 to 0.5. When the volume ratio VF is within this range, the thermal expansion coefficient of the film layer 2 is sufficiently reduced, and the film material is excellent in flexibility. Thereby, adhesiveness with a to-be-transferred body further improves. Furthermore, when the volume ratio VF is within this range, the flow of the thermosetting resin 2R is hardly hindered during thermocompression bonding. Therefore, the joining property between circuit members is improved, and the connection reliability of the obtained electronic component is also improved.

  The film material 10 is thermally transferred at a relatively low temperature (for example, 100 ° C. or less) such that the thermosetting resin 2R is not cured. Therefore, it is preferable that the film layer 2 is flexible even at room temperature from the viewpoint of adhesion to the transfer target.

  The flexibility of the film layer 2 at room temperature is represented by, for example, tensile strength. The tensile strength can be measured using a tensile tester. Specifically, the film layer 2 is overlapped so as to have a predetermined thickness (for example, 0.1 mm), and cut into a predetermined length and width (for example, length 30 mm × width 5 mm) to prepare a sample. . Both ends in the longitudinal direction of the obtained sample are each chucked with a pulling jig (chucking interval 20 mm), and the pulling jig is separated at a constant speed (for example, a speed of 100 mm / min). The strength when the sample breaks is defined as the tensile strength of the film layer 2. Thus, the tensile strength of the film layer 2 measured is preferably 10 to 200 mN, and more preferably 20 to 100 mN.

When the film layer 2 includes the conductive material 3, the volume ratio VP1 _0.5 of the conductive material 3 in the first region from the surface on the base material 1 side of the film layer 2 to 0.5T is the other surface of the film layer 2 Is preferably smaller than the volume ratio VP2 _0.5 of the conductive material 3 in the second region from 1 to 0.5T. By including more conductive material 3 on the transfer surface side of the film layer 2, the conductive material 3 is easily disposed near the upper part of the electrode of the circuit member that is the transfer target at the stage of thermal transfer. Therefore, when the other circuit member is laminated and thermocompression bonded, the conductive material easily enters between the counter electrodes, and the conductivity is further improved.

Moreover, it is preferable that many electroconductive materials 3 are contained in the area | region where the volume ratio VF of the fiber 2F is small. This is because the conductive material 3 can easily flow in the thermocompression bonding step. Thereby, the conductive material 3 is likely to enter between the counter electrodes. For example, when the fiber 2F has a volume ratio VF1 _0.15 > volume ratio VF2 _0.85 , the volume ratio VP1 _0.15 of the conductive material 3 in the first region from the surface on the substrate 1 side of the film layer 2 to 0.15 T It is preferable that the volume ratio VP2 _0.85 of the conductive material 3 in the second region from the other surface of the layer 2 to _{0.85 T} is smaller than the volume ratio VP1 _0.15 <volume ratio VP2 _0.85 . Furthermore, in this case, it is preferable that the conductive material 3 is not included in the first region from the surface on the base material 1 side of the film layer 2 to 0.15T. In addition, since the conductive material 3 enters the gap between the fibers 2F between the counter electrodes by the thermocompression bonding step, conduction is ensured even if the fibers 2F exist between the counter electrodes.

  The fibers 2F are included on the base material 1 side of the film layer 2 in a nonwoven fabric shape. It is preferable that the average thickness of a nonwoven fabric is 0.05T-0.2T with respect to the thickness T of a film layer from a viewpoint of bondability. Specifically, the average thickness of the nonwoven fabric is preferably 1 to 3 μm.

  The average thickness is, for example, an average value of thicknesses at arbitrary 10 locations of the nonwoven fabric. The thickness is a distance between the two main surfaces of the nonwoven fabric. Specifically, as for the thickness of the nonwoven fabric, take a photograph of the cross section of the film material 10 as described above, from any one point on the surface opposite to the base material 1 of the film layer 2 to the base material 1, When a line perpendicular to the surface is drawn, it is obtained as a distance between two fibers 2F that are farthest from the fibers 2F that overlap this line. The thickness of the nonwoven fabric is calculated in the same manner for other arbitrary plural points (for example, 9 points), and a value obtained by averaging the thicknesses is set as the average thickness of the nonwoven fabric. In calculating the thickness, a binarized image may be used.

(Film material 10C-10E)
3C shows that when the thickness of the film layer 2 is T, the volume ratio VF1 _0.5 of the fibers 2F in the first region from the surface of the film layer 2 on the substrate 1 side to 0.5T is the other of the film layer 2. The film material 10C is smaller than the volume ratio VF2 _0.5 of 2F fibers in the second region from the surface to 0.5T. 3D and 3E show that the volume ratio VF1 _0.85 of the fibers 2F in the first region from the surface on the base material 1 side of the film layer 2 to 0.85T is the volume ratio VF2 of the fibers 2F in the remaining region (second region). Film materials 10D and 10E smaller than _0.15 are shown.

  The film materials 10C to 10E are also useful when the linear expansion coefficients of the first circuit member and the second circuit member joined by the film material 10 are different. That is, by laminating a circuit member having a larger linear expansion coefficient so that the first region of the film layer 2 is opposed, the difference in coefficient of thermal expansion between each circuit member and the film layer is reduced, and the thermal stress is further increased. Decrease.

[manufacturing device]
(2-1 embodiment)
Hereinafter, an embodiment of a manufacturing apparatus 100A according to the present invention will be described with reference to FIG. 4A. FIG. 4A is a diagram illustrating a configuration example of a manufacturing apparatus according to the 2-1 embodiment. In 100 A of manufacturing apparatuses, the resin coating part is arrange | positioned between the fiber formation part and the drying part, and the base material 1 is conveyed downstream from the upstream of a manufacturing line. With the apparatus according to the present embodiment, the manufacturing method according to the first to first embodiments is performed, and, for example, the film materials 10A and 10B are manufactured.

[Base material supply unit]
The base material supply unit 200 is disposed in the uppermost stream of the manufacturing apparatus 100, and supplies the long base material 1 wound in a roll shape to the first transport conveyor 21, for example. In this case, the substrate 1 is wound around the supply reel 22, and the supply reel 22 rotates by driving the motor 23.

[Fiber forming part]
The substrate 1 is transferred to the fiber forming unit 300 by the first conveyor 21. The fiber forming unit 300 includes, for example, an electrospinning mechanism as a fiber spinning mechanism. The electrospinning mechanism includes an emitter 33 for discharging the first raw material liquid 30 installed above the fiber forming unit 300, and charging means for positively charging the discharged first raw material liquid 30 (see below). And a second transport conveyor 34 for transporting the base material 1 disposed so as to face the discharge body 33 from the upstream side to the downstream side. The 2nd conveyance conveyor 34 functions as a collector part which collects the fiber 2F with the base material 1. FIG.

  A plurality of discharge ports (not shown) for the first raw material liquid 30 are provided on the side of the emitter 33 facing the main surface of the substrate 1. The distance between the discharge port and the substrate 1 is, for example, 100 to 600 mm, although it depends on the scale of the manufacturing apparatus. The emitter 33 is installed above the fiber forming unit 300, and the second support 36 extending downward from the first support 35 parallel to the conveying direction of the substrate 1 has its own longitudinal direction of the substrate 1. It is supported so as to be parallel to the main surface.

  The charging means includes a voltage application device 37 that applies a voltage to the emitter 33 and a counter electrode 38 that is installed in parallel with the second transport conveyor 34. The counter electrode 38 is grounded. Thereby, a potential difference (for example, 20 to 200 kV) corresponding to the voltage applied by the voltage application device 37 can be provided between the emitter 33 and the counter electrode 38. The configuration of the charging unit is not particularly limited. For example, the counter electrode 38 may be negatively charged. Moreover, you may comprise the belt part of the 2nd conveyance conveyor 34 from a conductor instead of providing the counter electrode 38. FIG.

  The emitter 33 is made of a conductor, has a long shape, and its inside is hollow. The hollow portion serves as a housing portion that houses the first raw material liquid 30. The first raw material liquid 30 is supplied from the first raw material liquid tank 31 to the hollow of the discharge body 33 by the pressure of the pump 32 communicating with the hollow portion of the discharge body 33. Then, the first raw material liquid 30 is discharged from the discharge port toward the main surface of the substrate 1 by the pressure of the pump 32. The discharged first raw material liquid 30 is electrostatically exploded while moving in the space between the emitter 33 and the second conveyor 34 in a charged state, and generates a fibrous material (fiber 2F). The average fiber diameter of the fibers 2F thus generated is, for example, 1 μm or less.

  Note that the substrate 1 may be temporarily collected (for example, wound into a roll) after the fibers 2F are deposited. In this case, as described above, a protective sheet is preferably laminated on the substrate 1.

[Resin coating part]
Subsequently, the base material 1 is transported to the resin coating unit 400 by the second transport conveyor 34. FIG. 4A shows a case where coating is performed by a knife coating method.

  The resin coating unit 400 stores the second raw material liquid 40 installed above the resin coating unit 400 and supplies the first raw material liquid tank 41 to the base material 1 and the first raw material liquid tank 41. The nozzle 44 which coats the 1st raw material liquid applied to a base material, the knife coater 42 which adjusts the coating amount, and the 3rd conveyance conveyor 43 which conveys the base material 1 more downstream are provided. The coating amount of the second raw material liquid 40 is not particularly limited as long as it can cover the fibers 2F. For example, the coating amount may be adjusted so that the thickness T of the film layer 2 in the film material 10 is in the range of 5 to 100 μm.

[Dry section]
The base material 1 coated with the second raw material liquid 40 is transported to the drying unit 500 by the third transport conveyor 43, and part or all of the second solvent is removed. In the drying part 500, the warm air 51 is sent to the base material 1 from the warm air generator 50 arrange | positioned above the base material 1, and it removes by vaporizing the 2nd solvent. The temperature of the hot air 51 is not particularly limited as long as it is a temperature at which the second solvent is vaporized and the thermosetting resin 2R is not cured, and is appropriately set depending on the types of the second solvent and the thermosetting resin 2R. be able to.

[Recovery Department]
The film material 10 transported from the drying unit 500 by the fourth transport conveyor 52 is recovered by the recovery unit 600 disposed further downstream via the transport roller 61. When the substrate 1 is a long body, the collection unit 600 may incorporate a collection reel 62 that scrapes off the film material 10 being conveyed. The collection reel 62 is rotated by driving the motor 63.

  The manufacturing apparatus 100A cuts the laminated part and / or the obtained film material 10 (or only the film layer 2) obtained by laminating the protective sheet into a desired size and shape between the drying part 500 and the collecting part 600. A cutting part (both not shown) may be provided. A protective sheet is not specifically limited, The same thing as the above can be illustrated. The cutting method is not particularly limited. For example, the method of shearing using a rotary cutter or a straight type cutter is mentioned.

  The fiber formation part 300, the resin coating part 400, and the drying part 500 may be connected and may comprise one apparatus, as shown to FIG. 4A. In this case, while the base material 1 moves through the fiber forming unit 300, the resin coating unit 400, and the drying unit 500, the base material 1 is never collected (for example, wound into a roll), and is a film material. 10 can be manufactured (a so-called roll-to-roll manufacturing method). Therefore, productivity is further improved. Furthermore, since it is not necessary to arrange a collection unit (for example, a reel) between the fiber forming unit 300 and the resin coating unit 400 and / or between the resin coating unit 400 and the drying unit 500, space saving is achieved. Can be planned.

  Or after the base material 1 passes through the fiber formation part 300, the base material 1 is once collect | recovered and you may convey to the resin coating part 400 and the drying part 500 in a remote place. In this case, there is an advantage that the existing resin coating part and the drying part can be used.

(2-2 embodiment)
The 2-2 embodiment is the same as the 2-1 embodiment except that the fiber forming unit 300 is disposed between the resin coating unit 400 and the drying unit 500. With the apparatus according to the 2-2 embodiment, the manufacturing method according to the 1-2 embodiment is performed, and the film materials 10C and 10D are manufactured.

  The manufacturing apparatus 100B may include a stacking unit and / or a cutting unit (both not shown) between the drying unit 500 and the collection unit 600, as in the case of the 2-1 embodiment. A protective sheet is not specifically limited, The same thing as the above can be illustrated. The cutting method is the same as described above. Also in this embodiment, the resin coating unit 400, the fiber forming unit 300, and the drying unit 500 may be connected to form a single device as shown in FIG. 4B.

(2-3 embodiment)
The 2-3 embodiment is the same as the 2-1 embodiment except that the drying unit 500 is disposed between the resin coating unit 400 and the fiber forming unit 300. The manufacturing method according to the first to third embodiments is performed by the apparatus according to the second to third embodiments, and the film material 10E is manufactured.

  100C of manufacturing apparatuses may be provided with the lamination | stacking part and / or the cutting part (all are not shown) cut | disconnected between the fiber formation part 300 and the collection | recovery part 600 similarly to 2-3 embodiment. . A protective sheet is not specifically limited, The same thing as the above can be illustrated. The cutting method is the same as described above. Also in this embodiment, the resin coating unit 400, the drying unit 500, and the fiber forming unit 300 may be connected to form a single device as shown in FIG. 4C.

  According to the manufacturing method and the manufacturing apparatus of the present invention, a film material having a low coefficient of thermal expansion can be manufactured with high productivity. Therefore, the film material obtained by the method of the present invention is suitable as a film-like bonding material (for example, ACF, NCF, die bond film, etc.) for bonding circuit members together.

1: base material, 2: film layer, 2F: fiber, 2R: thermosetting resin, 3: conductive material, 10: film material, 21: first conveyor, 22: supply reel, 23: motor, 30: First raw material liquid, 31: first raw material liquid tank, 32: pump, 33: discharger, 34: second transport conveyor, 35: first support, 36: second support, 37: voltage application device, 38 : Counter electrode, 40: second raw material liquid, 41: second raw material liquid tank, 42: knife coater, 43: third transfer conveyor, 44: nozzle, 50: hot air generator, 51: hot air, 52: second 4 conveyor, 61: conveyor roller, 62: collection reel, 63: motor, 100, 100A, 100B, 100C: manufacturing apparatus, 200: substrate supply unit, 300: fiber forming unit, 400: resin coating unit, 500 : Drying section, 600: Collection section

Claims (12)

A first preparation step of preparing a substrate;
A second preparation step of preparing a first raw material liquid containing a first resin and a first solvent as a raw material of the fiber;
A third preparation step of preparing a second raw material liquid containing a thermosetting second resin and a second solvent;
A fiber deposition step of spraying the first raw material liquid on the base material to generate fibers containing the first resin from the first raw material liquid, and depositing the fibers on the base material;
A resin coating process for coating the base material with the second raw material liquid;
A drying step of removing the second solvent contained in the coated second raw material liquid,
The method for producing a film material, wherein the linear expansion coefficient CF of the first resin is smaller than the linear expansion coefficient CR of the cured second resin.   The method for producing a film material according to claim 1, wherein the resin coating step is performed between the fiber deposition step and the drying step.   The method for producing a film material according to claim 1, wherein the fiber deposition step is performed between the resin coating step and the drying step.   The method for producing a film material according to claim 1, wherein the drying step is performed between the resin coating step and the fiber deposition step.   The manufacturing method of the film material as described in any one of Claims 1-4 with which the said fiber deposition process is performed by the electrospinning method. Furthermore, the conveyance process which conveys the said base material with a conveyance belt,
Production of the film material as described in any one of Claims 1-5 which performs the said fiber deposition process, the said resin coating process, and the said drying process continuously with respect to the base material conveyed at the said conveyance process. Method.   The manufacturing method of the film material as described in any one of Claims 1-6 whose fiber diameter of the said fiber deposited is 1 micrometer or less.   The manufacturing method of the film material as described in any one of Claims 1-7 in which a said 2nd raw material liquid contains an electroconductive material further. A base material supply unit for supplying the base material to the conveyor belt;
Above the substrate to be conveyed, a fiber containing the first resin is generated from a first raw material liquid containing a first resin and a first solvent as a fiber raw material, and the generated fiber is applied to the substrate. A fiber forming part to be deposited;
A resin coating part that coats the surface of the substrate to be conveyed with a second raw material liquid containing a thermosetting second resin and a second solvent;
Removing the second solvent contained in the second raw material liquid coated on the substrate to be conveyed to form a film material;
A recovery unit that scrapes off the film material fed from the drying unit,
The apparatus for producing a film material, wherein the linear expansion coefficient CF of the first resin is smaller than the linear expansion coefficient CR of the cured second resin.   The apparatus for producing a film material according to claim 9, wherein the resin coating part is disposed between the fiber forming part and the drying part.   The apparatus for producing a film material according to claim 9, wherein the fiber forming part is disposed between the resin coating part and the drying part.   The manufacturing apparatus of the film material of Claim 9 with which the said drying part is arrange | positioned between the said resin coating part and the said fiber formation part.

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