JP2010033793A - Method for manufacturing particle transfer film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a particle transfer film having less untransferred parts of particles compared with conventional ones. <P>SOLUTION: The method for manufacturing the transfer film has a primary transfer process for primarily transferring particles held in pore parts of a transfer mold having a large number of pore parts on the surface, to the surface of an adhesive body, and a secondary transfer process for secondarily transferring the obtained particles on the surface of the adhesive body to the surface of a polymeric film by heating and pressurizing. The adhesive body is preferably formed of a thermosetting adhesive material. It is also preferable to separate the adhesive body from the polymeric film before the temperature by heating is lost in the secondary transfer process. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a particle transfer film, and more particularly to a method for producing a particle transfer film suitable for use in an anisotropic conductive film or the like.

  In recent years, various functions have been realized by regularly arranging particles and utilizing their regularity.

  For example, in the fields of electric and electronic devices, anisotropic conductive films imparted with anisotropic conductivity by regularly arranging particles on an adhesive sheet are used.

  Conventionally, a transfer method using a transfer mold has been widely used as a method for arranging particles. For example, in Patent Document 1, when manufacturing an anisotropic conductive film, conductive fine particles are put into a non-through hole of a conductive fine particle arranging jig (transfer type) by ultrasonic vibration. A method is disclosed in which a heated adhesive layer is pressed against the arranged surfaces.

  An attempt has been made to produce an anisotropic conductive film in which particles are arranged without using a transfer mold.

  For example, in Patent Document 2, after arranging conductive particles densely in a single layer on the surface of the pressure-sensitive adhesive sheet, an array sheet in which the conductive particles are spaced is produced by stretching the pressure-sensitive adhesive sheet. A method is disclosed in which a binder resin is stacked on the conductive particle side of the sheet and the conductive particles are embedded in the binder resin with a hot roll or the like, and then the array sheet is peeled off and an insulating adhesive is laminated.

JP 2003-220669 A JP 2007-217503 A

  However, the conventional technique using a transfer mold has the following problems.

  That is, when a transfer mold is used, the particles cannot be transferred if they are completely hidden within the holes of the transfer mold. On the other hand, if the particles are excessively exposed from the transfer-type hole portions, the particles cannot be held in the hole portions, and the arrangement of the particles is hindered. Therefore, in consideration of transferability and particle retention in the pores, the particles are usually held in the pores with their tops slightly protruding from the pores.

  However, when the transfer mold in this state is used for transfer to the polymer film, the contact area between the particles and the polymer film is small, and thus untransferred sites are likely to occur. In addition, if excessive heating is performed at the time of transfer in order to improve the transfer property from the transfer mold to the polymer film, the polymer film may be thermally deformed due to heat wrinkles in the polymer film. Since the polymer film becomes a member constituting a part of a product such as an anisotropic conductive film, it is preferable not to perform excessive heating during production. For these reasons, it has been difficult to improve transferability by the prior art.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for producing a particle transfer film in which the number of untransferred portions of particles is smaller than in the prior art.

  In order to solve the above problems, a transfer film manufacturing method according to the present invention includes a primary transfer step in which particles held in a transfer mold hole having a number of holes on the surface thereof are primarily transferred to the surface of the pressure-sensitive adhesive body. And a secondary transfer step in which the particles on the surface of the pressure-sensitive adhesive body are secondarily transferred to the surface of the polymer film by heating and pressing.

  Here, it is preferable that the said adhesive body is formed from the thermosetting adhesive material.

  In the secondary transfer step, the pressure-sensitive adhesive body and the polymer film are preferably separated before the temperature due to the heating is lost.

  Moreover, it is preferable that the adhesive force of the said adhesive body exists in the range of 0.1-0.6N / 25mm width by the peeling strength in 25 degreeC with respect to a polyethylene terephthalate.

The polymer film is preferably formed of a material having a viscosity of 2 × 10 ⁴ Pa · s or less at the secondary transfer temperature.

  In the method for producing a particle transfer film according to the present invention, the primary transfer process may be repeated.

  Moreover, electroconductive particle can be used suitably as said particle | grain.

  The gist of the particle transfer film according to the present invention is obtained by the above-described method for producing a particle transfer film.

  The gist of the anisotropic conductive film according to the present invention is the use of a particle transfer film obtained by the above-described method for producing a particle transfer film (however, conductive particles are used as particles).

  A method for producing an anisotropic conductive film according to the present invention uses a particle transfer film obtained by the above-described method for producing a particle transfer film (however, conductive particles are used as particles), and the conductive particles are polymerized. The gist of the invention is to include a step of embedding and holding the film in a film and a step of forming an adhesive layer on one side of the polymer film holding the electroconductive particles.

  In the method for producing a particle transfer film according to the present invention, in the primary transfer step, the particles held in the hole of the transfer mold are primarily transferred to the surface of the adhesive body due to the adhesiveness of the adhesive body. For this reason, the particles can be primarily transferred from the transfer mold to the surface of the pressure-sensitive adhesive body without heating. Moreover, although the particle | grains primarily transferred by the adhesive body surface are affixed with the adhesive body in the bottom part, the most part of the surface is in the exposed state.

  In the secondary transfer step, the particles on the surface of the adhesive body are secondarily transferred to the surface of the polymer film by heating and pressing. Therefore, the polymer film softened by heating and the particles come into contact with each other in a wider contact area, and the particles on the adhesive body side are secondarily transferred to the polymer film side.

  Therefore, according to the method for producing a particle transfer film according to the present invention, the number of untransferred particles of the particles is smaller than in the case of directly transferring the particles held in the transfer type hole to the polymer film. A transfer film can be manufactured.

  Here, when the said adhesive body is formed from the thermosetting adhesive material, the adhesiveness of an adhesive body falls by the heating at the time of secondary transfer. For this reason, the particles are more easily transferred to the polymer film softened by heating, which is likely to contribute to the improvement of secondary transferability.

  In the secondary transfer process, when separating the adhesive and polymer film before the temperature due to heating is lost, the secondary transferred particles are prevented from adhering to the adhesive body and falling off. It becomes easy.

  Moreover, when the adhesive strength of the adhesive body is within the specific range, the balance between the releasability from the transfer mold during primary transfer and the effect of suppressing the positional deviation of the particles after primary transfer is excellent.

In addition, when the polymer film is formed of a material having a viscosity of 2 × 10 ⁴ Pa · s or less at the secondary transfer temperature, the particles are easily transferred to the secondary film and after being cooled after the secondary transfer. However, the positional deviation of the particles is less likely to occur.

  In addition, when repeating the primary transfer step, as described above, since there are few untransferred parts of the particles, the alignment accuracy of the particles between repetitions (batch) is improved, and long objects with little deviation between the particle pitches. It becomes easy to manufacture a particle transfer film.

  Moreover, when the said particle | grain is an electroconductive particle, the particle | grain transfer film | membrane which can be used suitably for an anisotropic electrically conductive film is obtained.

  The anisotropic conductive film according to the present invention uses a particle transfer film obtained by the production method according to the present invention. Therefore, it is possible to reduce the conduction resistance failure caused by the untransferred portion of the particle.

  The anisotropic conductive film according to the present invention uses a particle transfer film obtained by the production method according to the present invention. Therefore, it is possible to obtain an anisotropic conductive film with little conduction resistance defect due to the untransferred part of the particle.

  Hereinafter, the method for producing a particle transfer film according to the present embodiment (hereinafter sometimes referred to as “the present production method”) and the anisotropic conductive film according to the present embodiment will be described in detail.

1. This manufacturing method This manufacturing method has at least the following primary transfer processes and secondary transfer processes. Hereinafter, each step will be described.

<Primary transfer process>
In this production method, the primary transfer step is a step of primary transfer of the particles held in the transfer-type holes having a number of holes on the surface to the surface of the pressure-sensitive adhesive body.

  FIG. 1 is a diagram schematically showing a specific example of the primary transfer process. First, as shown in FIG. 1A, a transfer mold 10 in which particles 12 are held in a large number of holes 10a and an adhesive body 14 are prepared. Here, as the pressure-sensitive adhesive body 14, an example in which the pressure-sensitive adhesive layer 14b is formed on the surface of the base material 14a is illustrated.

  Next, as shown in FIG. 1B, the particle holding surface of the transfer mold 10 and the adhesive layer 14b surface of the adhesive body 14 are brought close to or in contact with each other, and pressure is applied on the surface of the base material 14a of the adhesive body 14 The particles 12 are adhered to the surface of the adhesive layer 14b by rolling the roll 15 or the like.

  In this case, the above operation is preferably performed without heating from the viewpoint of easy primary transfer while maintaining the particle arrangement. In addition, the pressure is preferably 0.1 to 1 MPa, more preferably 0.1 to 0.5 MPa, and still more preferably from the viewpoint of suppressing adhesion to the transfer mold and excellent primary transferability. In the range of 0.1 to 0.3 MPa.

  Next, as shown in FIG. 1C, the transfer mold 10 and the adhesive body 14 are pulled apart. Thereby, the particles 12 in the hole 10 a of the transfer mold 10 are primarily transferred onto the surface of the adhesive body 14.

  In the primary transfer step, a transfer mold or pressure-sensitive adhesive in which particles are held in the hole may be prepared as follows, for example.

(Transfer type)
Examples of the transfer mold include etching on inorganic materials such as Si, ceramics, glass, and metals, various materials such as thermosetting resins, photocurable resins, and thermoplastic resins, and organic materials such as rubber. It can be prepared by forming a hole by a hole forming method according to the material, such as a method, an electroforming method, or an optical modeling method.

  The transfer mold may have a flat body shape such as a flat plate shape, a film shape, or a sheet shape, or may have a shape such as a belt shape. Further, it may have a curved body shape such as a roll shape. An optimum shape can be selected according to the material of the transfer mold. Preferably, it is a flat body shape from the viewpoints of transfer mold productivity, particle retention, and the like.

  The hole part of the transfer mold may be a through hole or a non-through hole as long as particles can be held in the hole part. Moreover, the hole part may be comprised from both the through-hole and the non-through-hole. The hole can be appropriately selected in consideration of the shape of the transfer mold and the like. For example, if the transfer mold is a flat body shape such as a flat plate shape, either a non-through hole or a through hole can be selected. If the transfer mold is a curved body such as a roll, a non-through hole may be selected.

  Specific examples of the shape of the hole include a substantially polygonal column shape such as a quadrangular prism and a hexagonal column, a substantially pyramid shape such as a quadrangular pyramid and a triangular pyramid, a substantially cylindrical shape, and a substantially hemispherical shape. . Preferably, from the viewpoint of particle retention, hole forming property, and the like, a shape such as a substantially polygonal column shape or a substantially columnar shape is preferable.

  For example, the holes may be regularly arranged in a lattice shape, a staggered shape, a honeycomb shape, a stripe shape, or the like, or may be formed at random. It can be selected according to the use of the particle transfer film obtained by this production method. Preferably, from the viewpoint of increasing the utility value of the particle transfer film, such as for an anisotropic conductive film, the holes are preferably arranged regularly.

  The hole is preferably formed to a depth that allows the top of the particle to protrude from the hole forming surface. This is because preferential contact with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive body has advantages such as improved primary transfer and excellent particle retention.

  Specifically, the upper limit of the ratio of the hole depth to the average particle diameter (= depth of the hole / average particle diameter of the particle) is preferably from the viewpoint of excellent particle transferability and the like. Less than 1, more preferably 0.95 or less, still more preferably 0.9 or less.

  On the other hand, the lower limit of the ratio of the depth of the hole to the average particle diameter of the particles (= depth of the hole / average particle diameter of the particles) is from the viewpoint of ensuring particle retention, ease of particle introduction, and the like. Preferably, it is 0.5 or more, more preferably 0.6 or more, and further preferably 0.75 or more.

  It is preferable that the hole has an opening slightly larger than the particle diameter of the particles to be introduced. This is because it is easy to introduce particles one by one for each hole, and it is easy to ensure the introduction of particles.

  Specifically, the upper limit of the ratio of the aperture size of the hole to the average particle size of the particles (= the size of the aperture of the hole / the average particle size of the particles) is one particle per hole. From the viewpoint of easy introduction, it is preferably less than 2, more preferably 1.8 or less, and still more preferably 1.6 or less.

  On the other hand, the lower limit of the ratio of the aperture size of the pores to the average particle size of the particles (= the size of the apertures of the pores / the average particle size of the particles) is preferably from the viewpoint of ensuring particle introduction properties, 1 or more, more preferably 1.05 or more, and even more preferably 1.1 or more.

  The depth of the hole is an average value of the depth measured for 10 arbitrarily selected holes by observing the transfer mold surface with a laser microscope. Further, the opening diameter of the hole is an average value of the diameters of the openings measured for 10 arbitrarily selected holes by observing the transfer mold surface with a laser microscope. The average particle size of the particles is a value measured by a particle size distribution measuring device (“PITA-1” manufactured by Seishin Enterprise) or an equivalent device.

  The method for introducing particles into the transfer-type hole is not particularly limited, and various methods can be adopted.

  For example, (1) after spraying or applying a dried particle powder or a dispersion in which this is dispersed in a solvent onto a transfer-type hole forming surface, using a brush, brush, blade, etc. Particles can be introduced into the pores, such as by scraping the surface.

  (2) After spraying or coating, introducing particles into the hole by applying vibration or magnetic force (in the case of conductive particles) from the outside or sucking particles from the bottom of the hole. Can do.

  (3) The particles can be introduced into the pores by immersing the transfer mold in the dispersion.

  (4) A plate-like member is arranged at a certain distance from the hole-forming surface of the transfer mold, the dispersion is introduced into the formed gap, and the transfer mold and / or plate-like member is slid. For example, the particles can be introduced into the pores.

  Since the particles are physically pushed into the pores, it is preferable to introduce the particles into the pores by the method (1) from the viewpoint of easily retaining the particles in the pores. More preferably, when the particles are introduced into the pores using the dry particle powder itself in the method (1) from the viewpoint that it is possible to carry out by a dry method and that it is easy to introduce particles one by one for each pore. good.

  In the case where the particles have conductivity, in the method (1), the particles are attracted to the transfer mold by a magnetic force from the side opposite to the hole forming surface from the viewpoint of easy introduction of the particles into the holes. The particles may be introduced into the holes by scraping the surface of the hole forming surface using a brush, brush, blade, or the like.

  The particles to be used are not particularly limited, and can be selected according to the use of the particle transfer film obtained by this production method.

  Specific examples of the particles include, for example, one or two or more conductive layers on the surface of various resin particles (metal plating with various metals such as gold, silver, white metal, nickel, copper, and alloys thereof) Examples include particles having a layer, a sputtered layer, etc .; various metal particles made of the above metals and alloys thereof; conductive particles such as carbon particles; various resin particles; insulating particles such as silica particles. These may be used alone or in combination.

(Adhesive)
As the adhesive body, as illustrated in FIG. 1, an adhesive body having an adhesive layer formed of various adhesive materials exhibiting adhesiveness in a non-heated state can be suitably used. This is because the surface of the non-sticky substrate can be easily pressed with a roll or the like, and is easy to handle.

  Examples of the substrate include polyethylene terephthalate (PET), polypropylene (PP), polyvinyl chloride (PVC), and synthetic paper.

  Examples of the adhesive material include thermosetting adhesive materials such as acrylic resin, epoxy resin, phenol resin, and polyester resin, and photocurable adhesive materials.

  The thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive body (thickness of the pressure-sensitive adhesive portion) is preferably not less than the average particle diameter of the particles from the viewpoint of easy primary transfer while maintaining the particle arrangement.

  As the adhesive material, the thermosetting adhesive material described above is suitable. This is because the adhesiveness of the adhesive body decreases due to heating during secondary transfer, and the particles are more easily transferred to the polymer film softened by heating, which contributes to the improvement of secondary transferability. is there.

  The adhesive strength of the adhesive is the peel strength at 25 ° C. with respect to polyethylene terephthalate, and the lower limit thereof is preferably 0.1 N / 25 mm width or more, more preferably 0.2 N / 25 mm width or more, and still more preferably 0.8. It is good that it is 3N / 25mm width or more. This is because it is easy to suppress the positional deviation of the particles after the primary transfer.

  On the other hand, the adhesive strength of the adhesive is the peel strength at 25 ° C. with respect to polyethylene terephthalate, and the upper limit thereof is preferably 0.6 N / 25 mm width or less, more preferably 0.5 N / 25 mm width or less, more preferably It is good that it is 0.4 N / 25 mm width or less. This is because it is easy to release from the transfer mold during the primary transfer. In addition, the said peeling strength is a value measured by the measuring method demonstrated in the below-mentioned Example.

<Secondary transfer process>
In this production method, the secondary transfer step is a step of secondarily transferring particles on the surface of the pressure-sensitive adhesive body to the surface of the polymer film by heating and pressing.

  FIG. 2 is a diagram schematically showing a specific example of the secondary transfer process. First, as shown in FIG. 2A, an adhesive body 14 on which particles 12 are primarily transferred and a polymer film 16 formed through the primary transfer step are prepared. Here, the polymer film 16 is formed on the surface of the base material 16a.

  Then, the particle transfer surface of the pressure-sensitive adhesive body 14 and the surface of the polymer film 16 are brought into contact with each other, and this laminate is supplied between a pair of heating / pressure rolls 18.

  Here, the heating temperature is preferably 90 to 140 ° C., more preferably 100 to 130 ° C., and still more preferably, from the viewpoint of sufficiently softening the polymer film and improving secondary transferability. It is good to exist in the range of 110-120 degreeC.

  In addition, the applied pressure is preferably 0.1 to 5 MPa, more preferably 1 to 5 MPa, and still more preferably 3 from the viewpoint of sufficiently bringing the polymer film into contact with each other and improving secondary transferability. It is good to be in a range of ˜5 MPa.

  Next, as shown in FIG. 2 (b), after passing between the heating and pressure rolls 18, the pressure-sensitive adhesive body 14 is peeled off. As a result, the particles 12 that have been primarily transferred to the pressure-sensitive adhesive body 14 are secondarily transferred to the surface of the polymer film 16, and a particle transfer film 20 as shown in FIG. 2C is obtained.

  At this time, the separation of the pressure-sensitive adhesive body 14 and the polymer film 16 is performed before the temperature due to the heating at the time of the secondary transfer is lost, that is, in the state where the temperature by the heating at the time of the above-described secondary transfer is on. Is preferred. This is because it is easy to suppress the secondary transferred particles from adhering to the pressure-sensitive adhesive body 14 side and dropping off. The pressure-sensitive adhesive body 14 and the polymer film 16 can be separated by winding each with a winding device.

  In the secondary transfer step, the polymer film is formed by using a coating solution prepared by adjusting the polymer material constituting the polymer film so as to have an appropriate solid content and viscosity using a known coating means such as a coater. It can be prepared by a method of coating on a material and drying as necessary, a method of press-molding the polymer material into a flat film, or the like.

The viscosity of the polymer constituting the polymer film is preferably 2 × 10 ⁴ Pa · s or less, more preferably 1.5 × 10 ⁴ Pa · s or less, even more preferably at the secondary transfer temperature. It is good that it is 1 × 10 ⁴ Pa · s or less. This is because the particles are easily subjected to secondary transfer, and even when the particles are cooled after the secondary transfer, the positional deviation of the particles hardly occurs.

  The viscosity is a value measured by a stress control type rheometer (for example, “AR500” manufactured by TA Instruments Japan Co., Ltd. is marketed).

  Specifically, various thermosetting resins, thermoplastic resins, rubbers, and the like can be used as the material constituting the polymer film. It can be appropriately selected depending on the use of the particle transfer film.

  More specifically, for example, epoxy resins, melamine resins, phenol resins, diallyl phthalate resins, bismaleimide triazine resins, unsaturated polyester resins, polyurethane resins, phenoxy resins, polyamide resins, polyimides Thermosetting resins such as polyamide resins, polyamide resins, polyester resins, polycarbonate resins, polyphenylene oxide resins, polyurethane resins, polyacetal resins, polyvinyl acetal resins, polyethylene resins, polypropylene resins, polyvinyl resins Examples thereof include thermoplastic resins such as, rubbers and elastomers containing one or more functional groups such as hydroxyl group, carboxyl group, vinyl group, amino group, and epoxy group. These may be contained alone or in combination of two or more.

  In these materials, various additives such as a curing agent, a curing accelerator, a modifier, an antioxidant, and a filler may be added, if necessary, one or more.

  The film thickness of the polymer film is not particularly limited, but can be determined in consideration of the application of the particle transfer film, the particle diameter of the particle, the film strength of the polymer film, the manufacturability, and the like.

  For example, when using a particle transfer film for an anisotropic conductive film, the upper limit of the film thickness of the polymer film is easy to obtain an appropriate resistance value, from the viewpoint of the movement of particles during pressure bonding, etc. Preferably, it is not more than 3/2 times the particle size of the particles, more preferably not more than 1 time the particle size of the particles, and more preferably not more than 2/3 times the particle size of the particles.

  On the other hand, the lower limit of the film thickness of the polymer film is preferably at least 1/10 times the particle diameter of the particle, more preferably from the viewpoint of secondary transferability of the particle, movement of the particle during pressure bonding, and the like. The particle size is 1/5 times the particle size, more preferably 1/3 times the particle size.

<Repeating primary transfer process>
This manufacturing method basically has the primary transfer step and the secondary transfer step described above. Here, the primary transfer process described above may be repeated.

  FIG. 3 is a diagram schematically showing a case where the primary transfer process is repeatedly performed. As shown in FIG. 3A, after the primary transfer described with reference to FIG. 1 is performed, the pressure-sensitive adhesive body 14 is supplied and wound up by the size of the transfer mold 10 to run. Then, the positions of the primary-transferred particles 12 and the newly prepared particles 12 in the hole 10a of the transfer mold 10 are confirmed with an optical microscope, an image analysis device, or the like, and aligned so as to have the same pitch. Do.

  Then, as shown in FIG. 1B, the particle holding surface of the transfer mold 10 and the adhesive layer 14b surface of the adhesive body 14 are brought close to or in contact with each other on the surface of the base material 14a of the adhesive body 14 The particles 12 are adhered to the surface of the adhesive layer 14b by rolling the pressure roll 16 or the like.

  Thereafter, as shown in FIG. 3B, the transfer mold 10 and the adhesive body 14 are pulled apart. Thereby, the particles 12 in the hole 10 a of the transfer mold 10 are primarily transferred onto the surface of the adhesive body 14.

  Thus, when the primary transfer process is repeated, the number of untransferred parts of the particles is small as described above, so that the alignment accuracy of the particles between repetitions (batch) is improved, and a long object with little deviation between the particle pitches. There is an advantage that it becomes easy to manufacture the particle transfer film.

2. Anisotropic Conductive Film The anisotropic conductive film according to the present embodiment uses a part of the particle transfer film obtained by the above-described method for manufacturing a particle transfer film. In this case, the particles basically have conductivity.

  FIG. 4 is a cross-sectional view schematically showing an example of the anisotropic conductive film according to the present embodiment. As shown in FIG. 4, the anisotropic conductive film 30 has a particle transfer film 20 (conductive particles 12, polymer film 16) and an adhesive layer 32.

  The anisotropic conductive film mentioned above can be manufactured as follows, for example. In the particle transfer film, basically, the particles are transferred to one surface of the polymer film, and the transferred particles protrude from the film surface.

  The anisotropic conductive film can be manufactured by covering the transfer surface with an adhesive layer.

  In addition, from the viewpoint of suppressing dropping of transferred particles and the like, the transferred particles are embedded and securely held in a polymer film, and then an adhesive layer is formed on at least one surface of the film, An anisotropic conductive film can be manufactured.

  Examples of methods for embedding and retaining the transferred particles in the polymer film include, for example, (1) a method of pressurizing the particles, and (2) softening the polymer film by heating and embedding the particles in the film by its own weight. The method of making it etc. can be illustrated. These methods may be performed in combination with each other.

  The method (1) is preferable from the viewpoint of easily holding the particles in the film. More preferably, in the method (1), the particles may be pressurized while heating the polymer film. Specifically, a laminating method or the like can be applied. In addition, the said pressurization can be performed through inclusions, such as a separator, on particle | grains arbitrarily.

  When the pressurization is performed, the applied pressure is not particularly limited. Selection may be made in consideration of film strength, mold strength, film thickness, particle strength, and the like. Usually, it is about 0.01-1 MPa.

  When performing the said heating, the heating temperature is not specifically limited. The heating temperature varies depending on the type of polymer to be used, heat resistance, and the like, but it is preferable to select a temperature of the polymer glass transition temperature + 20 ° C. to + 40 ° C. This is because it becomes easier to embed particles in the film.

  All of the particles may be embedded in the film, or a part of the particles may be exposed on at least one surface of the film surface.

  Note that the degree of embedding of the particles can be varied by appropriately adjusting the pressing force, pressurizing time, heating temperature, heating time, and the like.

  On the other hand, as the method for forming the adhesive layer, specifically, for example, a coating liquid prepared so that the adhesive layer material has an appropriate solid content and viscosity can be obtained using known coating means such as a coater. Examples thereof include a method of coating on the holding surface and drying as necessary, and a method of attaching a film-like adhesive layer prepared in advance by the above method.

  Specifically, various thermosetting resins, thermoplastic resins, rubbers, and the like can be used as the material constituting the adhesive layer.

  More specifically, for example, epoxy resins, melamine resins, phenol resins, diallyl phthalate resins, bismaleimide triazine resins, unsaturated polyester resins, polyurethane resins, phenoxy resins, polyamide resins, polyimides Resins, cyanate resins and other thermosetting resins, polyamide resins, polyester resins, polycarbonate resins, polyphenylene oxide resins, polyurethane resins, polyacetal resins, polyvinyl acetal resins, polyethylene resins, polypropylene resins Examples thereof include thermoplastic resins such as polyvinyl resins, rubbers and elastomers containing one or more functional groups such as hydroxyl group, carboxyl group, vinyl group, amino group and epoxy group. These may be contained alone or in combination of two or more.

  In these materials, one or more kinds of additives such as a curing agent, a curing accelerator, a modifier, an antioxidant, and a filler may be added as necessary.

  The material constituting the adhesive layer preferably contains a thermosetting resin mainly from the viewpoint of excellent adhesion to an object to be connected. Of the thermosetting resins, an epoxy resin is preferable.

  In addition, when using a thermosetting resin, the said thermosetting resin may be semi-hardened and made into the prepreg.

  The thickness of the adhesive layer takes into account the height of the conductor (IC chip bump, etc.) of the connected object to be bonded to the adhesive layer, and the amount of gap generated between the connected objects (IC chip and wiring board, etc.). Can be determined.

  The upper limit of the thickness of the adhesive layer is preferably 3 times or less, more preferably 2 times or less, and even more preferably 1.75 times or less the height of the conductor of the connected object to be bonded to the adhesive layer. Good to have.

  The lower limit of the thickness of the adhesive layer is preferably 1 time or more, more preferably 1.2 times or more, and even more preferably 1.3 times the height of the conductor of the connected object to be bonded to the adhesive layer. It is good to be above.

  Hereinafter, the present invention will be described in detail with reference to examples.

1. Particle Transfer Film <Example 1>
(Preparation of transfer mold)
Using a dry etching method, approximately cylindrical hole portions (cross-section: approximately circular shape with a diameter of 5.5 μm, depth: 3. By forming a large number of non-through holes of 5 μm and a pitch of 9 μm, a Si transfer mold was prepared. The hole forming area is 100 mm × 100 mm.

(Particle retention in the hole of the transfer mold)
Resin plating particles having an average particle diameter of 4 μm (Sekisui Chemical Co., Ltd., “Micropearl AU-204”), in which Ni plating layer and Au plating layer are sequentially coated on the surface of particles made of divinylbenzene-based crosslinked resin. And sprayed on the hole forming surface of the transfer mold.

  Then, with a permanent magnet (manufactured by Seiko Sangyo Co., Ltd., ferrite magnet, 1000 gauss) installed on the opposite side of the hole forming surface, an appropriate pressing force is applied with a brush while attracting resin plating particles to the transfer mold. The surface on which the hole was formed was scraped off while being applied.

  When the hole forming surface was observed with a microscope, one resin plating particle was held substantially per hole. The resin plating particles held in the holes slightly protruded from the top of the transfer-type hole forming surface.

  As described above, a transfer mold was prepared in which resin plating particles were held one by one in each of a large number of regularly arranged holes.

(Preparation of adhesive tape)
The following three types of adhesive tapes (1) to (3) were prepared as adhesive bodies.
Adhesive tape (1): Adhesive tape with an acrylic adhesive layer (thickness 22 μm) formed on the surface of a PET substrate (manufactured by Fujimori Co., Ltd., “TFB4130”, adhesive strength = 0.59 N / 25 mm width) .
Adhesive tape (2): Adhesive tape with an adhesive layer (thickness 8 μm) made of an acrylic adhesive material formed on the surface of a PET substrate (manufactured by Kimoto Co., Ltd., “Pro Save MS75”, adhesive strength = 0.19N) / 25 mm width).
Adhesive tape (3): Adhesive tape with an adhesive layer (thickness 8 μm) made of an acrylic adhesive material formed on the surface of a PET substrate (manufactured by Kimoto Co., Ltd., “Pro Save MS75”, adhesive strength = 0.07 N) / 25 mm width).

  In addition, the adhesive force of the prepared adhesive tape is the value calculated | required as follows. That is, a 25 mm wide test piece was collected from each adhesive tape, and the collected test piece was applied to a surface on which a PET film (“Lumirror” manufactured by Toray Industries, Inc.) was not surface-treated with a rubber roll (load 2 kg). Pasted together. Next, this was left for 30 minutes in an environment of 23 ° C. and 50% relative humidity, and then the PET film was peeled off under the conditions of a peel angle of 180 ° and a tensile speed of 300 mm / min, and the peel strength (N / 25 mm) was determined. . The average value of the peel strength measured three times was defined as the adhesive strength of each adhesive tape.

(Preparation of polymer film)
A polymer film having adhesiveness was prepared by the following procedure. That is, 23.39 parts by mass of an alcohol-soluble polyamide resin, 25.16 parts by mass of a phenoxy resin (manufactured by Toto Kasei Co., Ltd., “EFR-0010M30”), and an epoxy resin (manufactured by Toto Kasei Co., Ltd.) 4.9 parts by mass of “FX289EK75”), 2.67 parts by mass of epoxy resin (manufactured by Tohto Kasei Co., Ltd., “FX305EK70”), and melamine resin (manufactured by Sanwa Chemical Co., Ltd., “Nikarak MX-750”). 1.37 parts by mass, curing agent (Shikoku Kasei Co., Ltd., “C11Z”) 0.38 parts by mass and curing agent (Mitsubishi Gas Chemical Co., Ltd., “F-TMA”) 0.57 Mass parts, 24.26 parts by mass of methanol, 48.05 parts by mass of toluene, and 69.2 parts by mass of methyl cellosolve were mixed to prepare a polymer solution.

  Next, using a comma coater, the polymer solution was applied to the release surface of a continuously supplied base substrate (polyethylene terephthalate, thickness 38 μm, “PET38X” manufactured by Lintec Corporation).

  Next, this coating layer was dried at 160 ° C. for 90 seconds to form a flat polymer film made of a resin mainly composed of a polyamide resin and a phenoxy resin. Thereafter, the release surface of a separator (polyethylene terephthalate, thickness 75 μm, manufactured by Lintec Corporation, “PET75C”) was put on the surface of the polymer film and wound up.

In this way, a polymer film (thickness 1.5 μm, width 100 mm, 20 m) composed mainly of a polyamide-based resin and a phenoxy-based resin sandwiched between the base substrate and the separator was prepared. In addition, the viscosity at 110 ° C. of the resin material forming the polymer film was 1.0 × 10 ⁴ Pa · s.

(Preparation of particle transfer film)
First, the transfer mold was placed and fixed on the base with the particle holding surface facing upward.

  Next, an adhesive tape (1) stretched with a predetermined tension between a pair of support rolls was placed above the transfer mold so that the adhesive layer faced the transfer mold. The adhesive tape (1) is set so as to be continuously supplied from one supply source and to be continuously wound around the other winding source.

  Next, both support rolls are lowered, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape (1) is brought into contact with the transfer-type particle holding surface, and the substrate surface of the pressure-sensitive adhesive tape (1) is brought to room temperature (under non-heating). A rubber roll was pressed with a pressure of 01 to 1 MPa, and the roll was moved at 0.5 m / min to perform room temperature pressurization.

  Subsequently, both support rolls were raised and the adhesive tape (1) was pulled away from the transfer mold. As a result, the resin plating particles held in the hole of the transfer mold were primarily transferred onto the surface of the adhesive layer of the adhesive tape (1). FIG. 5 shows an SEM photograph after the primary transfer. As can be seen from FIG. 5, it can be seen that the resin plating particles can be primarily transferred onto the surface of the adhesive layer of the adhesive tape (1) while maintaining the regularity of the hole portion of the transfer mold. Moreover, it turns out that the resin plating particle | grains by which primary transfer was carried out are affixed on the adhesion layer surface at the bottom part, and most of the surfaces are in the exposed state.

  Next, the transfer surface of the resin plating particles of the pressure-sensitive adhesive tape (1) and the polymer film surface from which the separator was peeled were overlapped, and this was heated by a heat and pressure roll at a temperature of 110 ° C., a pressure of 5 MPa, and a roll speed of 0. Thermal lamination was performed under the condition of 2 m / min. Next, the adhesive tape (1) was peeled off from the polymer film immediately after the thermal lamination.

  As a result, the resin plating particles that were primarily transferred to the surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape (1) were secondarily transferred to the surface of the polymer film to produce a particle transfer film according to Example 1.

<Example 2>
In the production of the particle transfer film according to Example 1, the adhesive tape (1) was run by the size of the transfer mold after the primary transfer.

  Next, a new transfer mold holding the resin plating particles was placed and fixed on the base. At this time, confirm the positions of the resin plating particles primarily transferred to the adhesive tape (1) and the resin plating particles held in the new transfer mold with an optical microscope, and align them so that they have the same pitch. went.

  Next, both support rolls were lowered, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape (1) was brought into contact with the transfer type particle holding surface, and thereafter, the primary transfer process was repeated. Then, the separator (polyethylene terephthalate, thickness 50 μm, manufactured by Lintec Co., Ltd., “PET5011”) was aligned with the primary transfer surface and wound around a 3-inch core tube. This obtained the long adhesive tape (1) (length 20m) by which the resin plating particle was transcribe | transferred on the adhesion layer surface.

  Thereafter, the long adhesive tape (1) is unwound while the separator is peeled off, and thermal lamination is performed in the same manner as in Example 1 (secondary transfer process), whereby the long object according to Example 2 is obtained. Particle transfer film (length 20 m) was prepared.

<Example 3>
A particle transfer film according to Example 2 was prepared in the same manner as in the preparation of the particle transfer film according to Example 1, except that the adhesive tape (2) was used instead of the adhesive tape (1).

<Example 4>
In the production of the long particle transfer film according to Example 2, the long particle transfer film according to Example 4 is the same except that the adhesive tape (2) is used instead of the adhesive tape (1). Was made.

<Example 5>
A particle transfer film according to Example 5 was prepared in the same manner as in the preparation of the particle transfer film according to Example 1, except that the adhesive tape (3) was used instead of the adhesive tape (1).

<Example 6>
In the production of the long particle transfer film according to Example 2, the long particle transfer film according to Example 6 is the same except that the adhesive tape (3) is used instead of the adhesive tape (1). Was made.

<Comparative Example 1>
First, the transfer mold was placed and fixed on the base with the particle holding surface facing upward.

  Next, a polymer film stretched with a predetermined tension between a pair of support rolls was placed above the transfer mold so that the surface of the polymer film faces the transfer mold.

  Next, both support rolls are moved down, the surface of the polymer film from which the separator is peeled off is brought into contact with the transfer type particle holding surface, and the temperature of the base material of the polymer film is 130 ° C. and 0.01 to 1 MPa. The rubber roll was pressed with pressure, and the roll was moved at 0.5 m / min to perform heating and pressurization.

  As a result of the above operation, the polymer film was attached to the surface of the transfer mold, so air was blown onto the polymer film and cooled to 25 ° C.

  Next, both supporting rolls were raised, the polymer film was pulled away from the transfer mold, and the resin plating particles held in the holes of the transfer mold were directly transferred to the surface of the polymer film.

  As a result, a particle transfer film according to Comparative Example 1 in which the resin plating particles were transferred to the polymer film surface was produced.

<Comparative example 2>
In the production of the particle transfer film according to Comparative Example 1, the polymer film was caused to travel by the size of the transfer mold after the transfer.

  Next, a new transfer mold holding the resin plating particles was placed and fixed on the base. At this time, the positions of the resin plating particles transferred to the polymer film and the resin plating particles held in the new transfer mold were confirmed with an optical microscope and aligned so as to have the same pitch.

  Next, both support rolls were lowered, the surface of the polymer film was brought into contact with the transfer type particle holding surface, and thereafter the same operation was repeated. Thereby, a long particle transfer film (length 20 m) according to Comparative Example 2 was produced.

2. Evaluation (transferability evaluation)
The state of particles remaining on the transfer mold before and after the primary transfer was observed with a microscope. The transfer rate from the transfer mold was determined by the following calculation.
Transfer rate (%) = 100− (number of particles remaining on the transfer mold after primary transfer) / (number of holes on the transfer mold surface) × 100
Further, the residual state of the particles on the adhesive tape after the secondary transfer was observed with a microscope.

(Particle position deviation due to winding after primary transfer)
For Examples and Comparative Examples in which primary transfer was repeatedly performed to produce a long adhesive tape with a primary transfer particle and a polymer film, the adhesive tape and the polymer film were unwound, and the particle misalignment caused by winding Was observed with a microscope. As a result, when the particle alignment is almost maintained and the particle position deviation due to winding is not generated, the effect of suppressing the position deviation is extremely high. When there was a suppression effect, it was evaluated as “◯”, and when all the particles were misaligned, it was evaluated as “x” because there was no misalignment suppression effect.

  The above results are shown together with each condition in Table 1.

3. Results The following can be understood from the relative comparison of Table 1. That is, in Comparative Examples 1 and 2, the particles held in the transfer-type hole are directly transferred to the polymer film. For this reason, heating is necessary to soften the polymer film, and even when heated, the transfer rate is low and the transferability from the transfer mold is poor. That is, it can be seen that, for example, when an anisotropic conductive film is produced using the obtained particle transfer film, the conduction performance is likely to decrease due to the untransferred portion.

  On the other hand, in each of the examples, the particles held in the transfer-type holes are primarily transferred to the adhesive tape, and the primary-transferred particles are secondarily transferred to the polymer film. Therefore, it can be seen that the particles can be primarily transferred to the adhesive tape from the transfer mold at a high transfer rate and while maintaining the particle arrangement without heating. Moreover, the particle | grains primarily transferred by the adhesive tape are affixed on the adhesive tape in the bottom part, and most of the surfaces are exposed. Therefore, it can be seen that the polymer film softened by heating is brought into contact with the surface of more particles, and secondary transfer to the polymer film side is possible with good transferability. Therefore, for example, when an anisotropic conductive film is produced using the obtained particle transfer film, it can be seen that the number of untransferred parts is smaller than in the prior art, and it is difficult to cause a decrease in conduction performance due to this. .

  In addition, when the examples are compared, if the adhesive force of the adhesive tape is 0.1 N / 25 mm width or more, the adhesive tape with primary transfer particles is lengthened in producing a long particle transfer film. Even if it winds, it can be said that the position shift of the particle | grains by winding is hard to produce. Therefore, it can be seen that it is easy to manufacture a long particle transfer film having a good particle arrangement by avoiding the influence of the particle position deviation due to winding. It can also be seen that if the adhesive strength of the adhesive tape is 0.6 N / 25 mm width or less, the release from the transfer mold can be performed well during primary transfer.

4). Production of Anisotropic Conductive Film Next, each anisotropic conductive film according to the example was produced by the following procedure using each particle transfer film according to the obtained example.

  First, a separator (polyethylene terephthalate, thickness 38 μm, “PET38C” manufactured by Lintec Co., Ltd.) is stacked on the surface of the particle transfer film, and this is performed under the conditions of a temperature of 140 ° C., a pressure of 0.1 MPa, and a heating and pressing time of 60 seconds. Heat laminated.

  As a result, the resin plating particles transferred to the surface of the polymer film were embedded in the film while maintaining the regular arrangement.

  Next, 90 parts by mass of a dicyclopentadiene type epoxy resin (Dainippon Ink Co., Ltd., “Epiclon HP7200HH”) and nitrile rubber (NBR) (Nippon Zeon Co., Ltd., “Nipol 1072J”) 10 parts by mass Then, 187 parts by mass of a curing agent (manufactured by Asahi Kasei Chemicals Corporation, “Novacure HXA3932HP”) was diluted with toluene so that the solid content was 42% to prepare an adhesive solution.

  Next, the above adhesive solution was applied to the release surface of a continuously supplied base substrate (polyethylene terephthalate, thickness 38 μm, “PET38C” manufactured by Lintec Corporation) using a comma coater.

  Subsequently, this coating layer was dried at 110 ° C. for 90 seconds to form an adhesive layer (thickness 20 μm). Then, the release surface of the separator (polyethylene terephthalate, thickness 38 μm, manufactured by Lintec Corporation, “PET38B”) was put on the surface of the adhesive layer and wound up.

  Thus, an adhesive layer sandwiched between the base substrate and the separator was prepared.

  Next, the surface of the adhesive layer exposed by peeling off the separator and the surface (transfer surface side) of the particle transfer film were superposed and bonded together.

  Thus, an adhesive layer was formed on one side of the particle transfer film.

  As described above, each anisotropic conductive film having a two-layer structure of a particle transfer film and an adhesive layer was produced.

  Although one embodiment and one example of the present invention have been described above, the present invention is not limited to the above embodiment and example, and various modifications can be made without departing from the spirit of the present invention. is there.

It is the figure which showed typically the specific example of the primary transfer process in the manufacturing method of the particle transfer film concerning this embodiment. It is the figure which showed typically the specific example of the secondary transfer process in the manufacturing method of the particle transfer film concerning this embodiment. It is the figure which showed typically the case where a primary transfer process is repeatedly performed in the manufacturing method of the particle transfer film concerning this embodiment. It is sectional drawing which showed typically an example of the anisotropic electrically conductive film which concerns on this embodiment. FIG. 3 is a diagram showing an SEM photograph after primary transfer in Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Transfer mold | type 10a Hole part 12 Particle | grain 14 Adhesive body 14a Base material 14b Adhesive layer 15 Pressure roll 16 Polymer film 16a Base material 18 Heating / Pressure roll 20 Particle transfer film 30 Anisotropic conductive film 32 Adhesive layer

Claims (10)

A primary transfer step for primary transfer of particles held in a transfer-type hole having a large number of holes on the surface thereof to the surface of the adhesive;
A secondary transfer step in which the particles on the surface of the adhesive body are secondarily transferred to the surface of the polymer film by heating and pressing; and
A method for producing a particle transfer film, comprising:   The method for producing a particle transfer film according to claim 1, wherein the adhesive body is formed of a thermosetting adhesive material.   The method for producing a particle transfer film according to claim 1 or 2, wherein, in the secondary transfer step, the pressure-sensitive adhesive body and the polymer film are separated before the temperature due to the heating is lost.   The particle transfer according to any one of claims 1 to 3, wherein the adhesive strength of the adhesive is within a range of 0.1 to 0.6 N / 25 mm width as a peel strength at 25 ° C with respect to polyethylene terephthalate. A method for producing a membrane. 5. The particle transfer film according to claim 1, wherein the polymer film is formed of a material having a viscosity of 2 × 10 ⁴ Pa · s or less at a secondary transfer temperature. Method.   6. The method for producing a particle transfer film according to claim 1, wherein the primary transfer step is repeated.   The method for producing a particle transfer film according to claim 1, wherein the particles are conductive particles.   A particle transfer film obtained by the method for producing a particle transfer film according to claim 1.   An anisotropic conductive film using a particle transfer film obtained by the method for producing a particle transfer film according to claim 7. Using the particle transfer film obtained by the method for producing a particle transfer film according to claim 7, embedding and holding the conductive particles in a polymer film;
Forming an adhesive layer on one side of the polymer film holding the conductive particles;
The manufacturing method of the anisotropic electrically conductive film which has this.