JP2019029135A - Anisotropic conductive film, manufacturing method thereof, connecting structure, and manufacturing method thereof - Google Patents

Abstract

To provide a manufacturing method of an anisotropic conductive film useful for manufacturing a connection structure having both excellent insulation reliability and conduction reliability even when a connecting portion of circuit members to be electrically connected to each other is minute.SOLUTION: A manufacturing method of an anisotropic conductive film according to the present invention includes, in this order, (a) a step of accommodating one or a plurality of solder particles respectively in a plurality of openings provided in the transfer mold, (b) a step of obtaining a first film to which the solder particles are transferred by bringing an insulating adhesive component into contact with the side where the transfer mold opening is provided, and (c) a step of obtaining an anisotropic conductive film by forming a second film including the insulating adhesive component on the surface of the first film on the side to which the solder particles are transferred.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an anisotropic conductive film and a manufacturing method thereof, and a connection structure and a manufacturing method thereof.

  The method of mounting the liquid crystal driving IC on the liquid crystal display glass panel can be roughly divided into two types, COG (Chip-on-Glass) mounting and COF (Chip-on-Flex) mounting. In COG mounting, a liquid crystal driving IC is directly bonded onto a glass panel using an anisotropic conductive adhesive containing conductive particles. On the other hand, in COF mounting, a liquid crystal driving IC is bonded to a flexible tape having metal wiring, and these are bonded to a glass panel using an anisotropic conductive adhesive containing conductive particles. The term “anisotropic” as used herein means that conduction is achieved in the pressurizing direction and insulation is maintained in the non-pressurizing direction.

By the way, with the recent high definition of liquid crystal display, the metal bumps which are circuit electrodes of the liquid crystal driving IC have been narrowed in pitch and area, so that the conductive particles of the anisotropic conductive adhesive are adjacent to each other. There is a risk of causing a short circuit by flowing out between the electrodes. This tendency is particularly remarkable in COG mounting. When the conductive particles flow out between adjacent circuit electrodes, the number of conductive particles trapped between the metal bumps and the glass panel is reduced, which may cause a connection failure in which the connection resistance between the facing circuit electrodes is increased. Such a tendency is more prominent when conductive particles of less than 20,000 / mm ² are introduced per unit area.

As a method for solving these problems, a method has been proposed in which a plurality of insulating particles (child particles) are attached to the surface of conductive particles (mother particles) to form composite particles. For example, Patent Documents 1 and 2 propose a method of attaching spherical resin particles to the surface of conductive particles. Furthermore, even when 70,000 particles / mm ² or more of conductive particles are charged per unit area, insulating coated conductive particles having excellent insulation reliability have been proposed. In Patent Document 3, the first insulating particles and Insulating coated conductive particles in which second insulating particles having a glass transition temperature lower than that of the first insulating particles are attached to the surface of the conductive particles have been proposed. Patent Document 4 proposes a conductive paste containing solder particles from the viewpoint of further strengthening the connection between electrodes.

Japanese Patent No. 4777385 Japanese Patent No. 3869785 JP 2014-17213 A Japanese Patent Laid-Open No. 2006-76494

By the way, when the connection location of the circuit members to be electrically connected to each other is very small (for example, a bump area of less than 2000 μm ² ), it is preferable to increase the conductive particles in order to obtain stable conduction reliability. For these reasons, there are cases where 100,000 particles / mm ² or more of conductive particles are introduced per unit area. However, when the connection location is very small as described above, even if the insulating coated conductive particles described in Patent Documents 1 to 3 are used, it is difficult to balance conduction reliability and insulation reliability, and there is still room for improvement. was there. On the other hand, when the conductive paste containing solder particles described in Patent Document 4 is used, there is a problem that the insulation reliability is insufficient, although the conduction reliability can be sufficiently ensured.

  The present invention has been made in view of the above-described problems, and manufactures a connection structure that is excellent in both insulation reliability and conduction reliability even when connection portions of circuit members to be electrically connected to each other are minute. An object of the present invention is to provide an anisotropic conductive film useful for the production and a method for producing the same. Moreover, an object of this invention is to provide the connection structure manufactured using this anisotropic conductive film, and its manufacturing method.

In order to solve the above-mentioned problems, the present inventors have examined the reason why the insulation resistance value is lowered in the conventional method. As a result, in the inventions described in Patent Documents 1 and 2, the coverage of the insulating particles coated on the surface of the conductive particles is low, and the input amount of the conductive particles of about 20,000 / mm ² or less per unit area Even so, it has been found that the insulation resistance value tends to decrease.

In the invention described in Patent Document 3, in order to compensate for the disadvantages of the invention described in Patent Documents 1 and 2, the first insulating particles and the second insulating particles having a glass transition temperature lower than that of the first insulating particles are used. It adheres to the surface of the conductive particles. Thereby, if the input amount of the conductive particles is about 70,000 particles / mm ² per unit area, the insulation resistance value can be kept sufficiently high. However, it has been found that the insulation resistance value may be insufficient when the amount of conductive particles charged is 100,000 / mm ² or more per unit area.

In the invention described in Patent Document 4, it is recognized that by using a conductive paste containing solder particles, excellent conduction reliability can be achieved as compared with the inventions described in Patent Documents 1 to 3. When the connection parts of the circuit members to be electrically connected to each other are very small (for example, the bump area is less than 2000 μm ² ), the solder particles tend to remain other than the connection part between the bumps, so that the insulation reliability is insufficient. It turns out that there is a possibility.

The present invention has been made based on the above findings of the present inventors. The present invention provides a method for producing an anisotropic conductive film comprising the following steps in this order.
(A) A step of accommodating one or a plurality of solder particles in a plurality of openings provided in the transfer mold.
(B) The process of obtaining the 1st film by which the solder particle was transcribe | transferred by making the adhesive agent component which has insulation on the side in which the transcription | transfer type opening part is provided.
(C) The process of obtaining an anisotropic conductive film by forming the 2nd film which consists of an adhesive agent component which has insulation on the surface of the 1st film of the side by which the solder particle was transcribe | transferred.

  According to the method for producing an anisotropic conductive film, by using a transfer mold, a particle group composed of one solder particle or a plurality of solder particles is formed in a predetermined region in the thickness direction of the anisotropic conductive film. An anisotropic conductive film arranged so as to be separated from one adjacent solder particle or particle group can be manufactured. For example, the position and number of solder particles in the anisotropic conductive film can be sufficiently controlled by manufacturing the anisotropic conductive film using a transfer mold corresponding to the pattern of the electrode to be connected. By manufacturing a connection structure using such an anisotropic conductive film, the number of solder particles existing between a pair of electrodes to be electrically connected to each other should be sufficiently ensured while insulating properties should be maintained. The number of solder particles existing between adjacent electrodes can be sufficiently reduced. Thereby, even if the connection location of a circuit member is minute, the connection structure which is excellent in both insulation reliability and conduction | electrical_connection reliability can be manufactured sufficiently efficiently and stably.

  Solder particles may be exposed on the surface of the first film obtained in the step (b), or solder particles may be embedded on the surface side of the first film. In order to embed the solder particles on the surface side of the first film, in the step (b), the adhesive component may be inserted into the opening. Further, in the first film obtained in the step (b), the step (b) may include a step of curing the adhesive component after the transfer of the solder particles in order to fix the transferred solder particles. Good.

  In this invention, it is preferable that the average particle diameter of a solder particle is 0.6-15 micrometers. The solder particles preferably contain tin or a tin alloy. Specific examples of the tin alloy constituting the solder particles include In—Sn alloy, In—Sn—Ag alloy, Sn—Bi alloy, Sn—Bi—Ag alloy, Sn—Ag—Cu alloy, and Sn—Cu alloy. . From the viewpoint of achieving high conduction reliability, the surface of the solder particles is preferably coated with a flux component.

  The present invention provides an anisotropic conductive film having the following constitution. That is, the anisotropic conductive film according to the present invention includes an insulating film made of an adhesive component having an insulating property and a plurality of solder particles arranged in the insulating film, and the anisotropic conductive film In the vertical cross section, the particle group composed of one solder particle or a plurality of solder particles is arranged so as to be laterally arranged in a state of being separated from one adjacent solder particle or particle group. Here, the “longitudinal section” means a section orthogonal to the main surface of the anisotropic conductive film, and the “lateral direction” means a direction parallel to the main surface of the anisotropic conductive film. .

  From the viewpoint of achieving both superior insulation reliability and conduction reliability of the connection structure, it is preferable that the particle groups are regularly arranged in the cross section of the anisotropic conductive film.

  The present invention provides a method for producing a connection structure using the anisotropic conductive film. That is, the manufacturing method of the connection structure according to the present invention provides a first circuit member having a first substrate and a first electrode provided on the first substrate; Providing a second circuit member having a second electrode to be electrically connected; a surface having a first electrode of the first circuit member and a surface having a second electrode of the second circuit member The anisotropic conductive film is disposed between the laminated body including the first circuit member, the anisotropic conductive film, and the second circuit member pressed in the thickness direction of the laminated body. The first electrode and the second electrode are electrically connected via the solder by heating to the melting point of the solder particles or higher, and the first circuit member and the second circuit member are bonded.

  According to the method for manufacturing a connection structure, a connection structure that is excellent in both insulation reliability and conduction reliability is sufficiently efficient even if the connection portion between the first electrode and the second electrode is minute. It can be manufactured stably. That is, in a state where the laminate is pressed in the thickness direction, the laminate is heated to a temperature higher than the melting point of the solder particles, so that the solder particles are melted between the first electrode and the second electrode. Collectively, the first electrode and the second electrode are joined via solder. Thereby, it is possible to obtain good conduction reliability between the first electrode and the second electrode. In addition to this, the solder particles gather together while melting between the first electrode and the second electrode, so that it is difficult for the solder particles to remain between adjacent electrodes that should maintain insulation. The occurrence of short circuit is suppressed, and high insulation reliability can be obtained.

  The present invention provides a connection structure having the following configuration. That is, the connection structure according to the present invention is electrically connected to the first circuit member having the first substrate and the first electrode provided on the first substrate, and the first electrode. A second circuit member having a second electrode, a solder joint interposed between the first electrode and the second electrode, and provided between the first circuit member and the second circuit member And an insulating adhesive layer bonded to the first circuit member and the second circuit member.

  In the present invention, it is preferable that at least one of the first electrode and the second electrode is made of a material selected from the group consisting of copper, nickel, palladium, gold, silver and alloys thereof, and indium tin oxide. . When at least one of the first electrode and the second electrode is made of copper, the first electrode and the second electrode may be connected via a layer made of an intermetallic compound. The thickness of the layer made of the intermetallic compound is preferably 0.1 to 10.0 μm from the viewpoint of conduction reliability and connection strength. The “layer composed of an intermetallic compound” refers to a layer formed by diffusion of copper in the solder layer when the solder particles are melted to form the solder layer.

  According to the present invention, an anisotropic conductive useful for manufacturing a connection structure excellent in both insulation reliability and conduction reliability even if connection portions of circuit members to be electrically connected to each other are minute. Films and methods for making the same are provided. Moreover, according to this invention, the connection structure manufactured using this anisotropic conductive film and its manufacturing method are provided.

FIG. 1 is a longitudinal sectional view schematically showing a first embodiment of an anisotropic conductive film according to the present invention. 2A is a schematic cross-sectional view taken along line IIa-IIa shown in FIG. 1, and FIG. 2B is a cross-sectional view schematically showing a modification of the first embodiment. FIG. 3 is a longitudinal sectional view schematically showing a second embodiment of the anisotropic conductive film according to the present invention. FIG. 4A is a schematic cross-sectional view taken along line IVa-IVa in FIG. 3, and FIG. 4B is a cross-sectional view schematically showing a modification of the second embodiment. FIG. 5A is a plan view schematically showing an example of a transfer mold, and FIG. 5B is a cross-sectional view taken along the line bb shown in FIG. FIG. 6 is a cross-sectional view schematically showing a state where one solder particle is captured in each recess of the transfer mold. Fig.7 (a)-FIG.7 (c) are sectional drawings which show typically an example of the manufacture process of the anisotropic conductive film which concerns on 1st embodiment. FIGS. 8A and 8B are a cross-sectional view and a plan view schematically showing a state in which a plurality of solder particles are accommodated in the respective concave portions of the transfer mold. Fig.9 (a)-FIG.9 (c) are sectional drawings which show typically an example of the manufacturing process of the anisotropic conductive film which concerns on 2nd embodiment. FIG. 10 is an enlarged view showing a part of the connection structure according to the present invention, and schematically shows a first example in which the first electrode and the second electrode are electrically connected by solder. FIG. FIG. 11 is an enlarged view of a part of the connection structure according to the present invention, and schematically shows a second example in which the first electrode and the second electrode are electrically connected by solder. FIG. FIG. 12 is an enlarged view showing a part of the connection structure according to the present invention, and schematically shows a third example in which the first electrode and the second electrode are electrically connected by solder. FIG. FIG. 13 is an enlarged view showing a part of the connection structure according to the present invention, and schematically shows a fourth example in which the first electrode and the second electrode are electrically connected by solder. FIG. FIG. 14 is an enlarged view of a part of the connection structure according to the present invention, and is a schematic diagram of a fifth example in which the first electrode and the second electrode are electrically connected by solder. FIG. FIG. 15 is an enlarged view showing a part of the connection structure according to the present invention, and schematically shows a sixth example in which the first electrode and the second electrode are electrically connected by solder. FIG. FIGS. 16A and 16B are cross-sectional views schematically showing a first example of the manufacturing process of the connection structure according to the present invention. FIG. 17A and FIG. 17B are cross-sectional views schematically showing a second example of the manufacturing process of the connection structure according to the present invention. 18 (a) and 18 (b) are cross-sectional views schematically showing a third example of the manufacturing process of the connection structure according to the present invention. FIGS. 19A and 19B are cross-sectional views schematically showing a fourth example of the manufacturing process of the connection structure according to the present invention. 20 (a) and 20 (b) are cross-sectional views schematically showing a fifth example of the manufacturing process of the connection structure according to the present invention. FIG. 21A and FIG. 21B are cross-sectional views schematically showing a sixth example of the manufacturing process of the connection structure according to the present invention. FIG. 22 is a plan view schematically showing a first example of the relationship between the positions of the solder particles of the anisotropic conductive film and the positions of the bumps (electrodes) before being pressed and heated. FIG. 23 is a plan view schematically showing a second example of the relationship between the positions of the solder particles of the anisotropic conductive film and the positions of the bumps (electrodes) before being pressed and heated. FIG. 24 is a plan view schematically showing a third example of the relationship between the positions of the solder particles of the anisotropic conductive film and the positions of the bumps (electrodes) before being pressed and heated. FIG. 25 is a plan view schematically showing a fourth example of the relationship between the positions of the solder particles of the anisotropic conductive film and the bumps (electrodes) before being pressed and heated.

  Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments. The materials exemplified below may be used alone or in combination of two or more unless otherwise specified. The content of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. The numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in the present specification, the upper limit value or lower limit value of a numerical range of a certain step may be replaced with the upper limit value or lower limit value of the numerical range of another step. In the numerical range described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.

<Anisotropic conductive film>
An anisotropic conductive film 10 according to the first embodiment shown in FIG. 1 includes an insulating film 2 made of an adhesive component having an insulating property, and a plurality of solder particles 1 arranged in the insulating film 2. It is configured. In a predetermined longitudinal section of the anisotropic conductive film 10, one solder particle 1 is arranged so as to be arranged in the horizontal direction (left and right direction in FIG. 1) in a state of being separated from one adjacent solder particle 1. In other words, the anisotropic conductive film 10 has, in its longitudinal section, a central region 10a in which a plurality of solder particles 1 are arranged in a row in the horizontal direction, and surface side regions 10b, 10c in which the solder particles 1 are not substantially present. And is composed of.

  FIG. 2A is a schematic cross-sectional view taken along the line IIa-IIa shown in FIG. As shown in the figure, the solder particles 1 are regularly arranged in the cross section of the anisotropic conductive film 10. As shown in FIG. 2 (a), the solder particles 1 may be regularly and substantially equally spaced with respect to the entire region of the anisotropic conductive film 10, as shown in FIG. 2 (b). As in the modified example, in the cross section of the anisotropic conductive film 10, a region 10d in which the plurality of solder particles 1 are regularly arranged and a region 10e in which the solder particles 1 are not substantially present are regular. The solder particles 1 may be arranged so as to be formed. For example, the position and number of solder particles 1 may be set according to the shape, size, pattern, etc. of the electrodes to be connected.

  An anisotropic conductive film 20 according to the second embodiment shown in FIG. 3 includes an insulating film 2 made of an adhesive component having insulating properties, and a plurality of particle groups 1A arranged in the insulating film 2. It is configured. The particle group 1 </ b> A is composed of a plurality of solder particles 1. In a predetermined longitudinal section of the anisotropic conductive film 20, one particle group 1A is arranged in the lateral direction (left and right direction in FIG. 3) in a state of being separated from one adjacent particle group 1A. In other words, the anisotropic conductive film 20 includes a central region 20a in which a plurality of particle groups 1A are arranged in a row in the longitudinal section, and surface side regions 20b and 20c in which the particle group 1A does not substantially exist. And is composed of.

  FIG. 4A is a schematic cross-sectional view taken along line IVa-IVa shown in FIG. As shown in the figure, in the cross section of the anisotropic conductive film 20, the particle group 1A is regularly arranged. As shown in FIG. 4A, the particle group 1A may be regularly and substantially equally spaced with respect to the entire region of the anisotropic conductive film 20, as shown in FIG. As in the modified example, in the cross section of the anisotropic conductive film 20, the region 20d in which the plurality of particle groups 1A are regularly arranged and the region 20e in which the particle groups 1A are not substantially present are regular. The particle group 1A may be arranged so as to be formed. For example, the position and number of the particle group 1A may be set according to the shape, size, pattern, and the like of the electrode to be connected.

(Solder particles)
The particle size of the solder particles 1 is, for example, 0.4 to 30 μm, and may be 0.5 to 20 μm or 0.6 to 15 μm. When the particle size of the solder particles 1 is less than 0.4 μm, the solder particles 1 are easily affected by the oxidation of the solder surface, and the solder particles 1 are melted in a state where the solder particles 1 are pressed by a pair of electrodes to be electrically connected. Even when heated to the above, the solder particles 1 tend to remain as fine particles without melting, and the conduction reliability tends to be insufficient. On the other hand, when the particle size of the solder particles 1 exceeds 30 μm, the insulation reliability tends to be insufficient.

  The average particle diameter of the solder particles 1 is, for example, 0.6 to 15 μm, and may be 1.0 to 12 μm or 1.2 to 10 μm. When the average particle diameter of the solder particles 1 is less than 0.6 μm, the solder particles 1 are easily affected by oxidation of the solder surface, and the solder particles 1 are pressed in a state where the solder particles 1 are pressed by a pair of electrodes to be electrically connected. Even when heated to the melting point or higher, the solder particles 1 tend to remain as fine particles without melting, and the conduction reliability tends to be insufficient. On the other hand, if the average particle size of the solder particles 1 exceeds 15 μm, the insulation reliability tends to be insufficient.

  The particle size of the solder particles 1 can be measured by observation using a scanning electron microscope (hereinafter, SEM). That is, the average particle diameter of the solder particles can be obtained by measuring the particle diameter of 300 arbitrary solder particles by observation using an SEM and taking the average value thereof.

The solder particle 1 contains tin or a tin alloy. As the tin alloy, for example, In—Sn, In—Sn—Ag, Sn—Bi, Sn—Bi—Ag, Sn—Ag—Cu, and Sn—Cu can be used, and the following examples are given.
In-Sn (In 52 mass%, Bi48 mass% melting point 118 ° C)
In-Sn-Ag (In 20% by mass, Sn 77.2% by mass, Ag 2.8% by mass, melting point 175 ° C.)
・ Sn-Bi (Sn43% by mass, Bi57% by mass, melting point 138 ° C.)
・ Sn-Bi-Ag (Sn 42 mass%, Bi 57 mass%, Ag 1 mass% melting point 139 ° C.)
Sn-Ag-Cu (Sn 96.5% by mass, Ag 3% by mass, Cu 0.5% by mass, melting point 217 ° C.)
Sn-Cu (Sn 99.3 mass%, Cu 0.7 mass% melting point 227 ° C)

  The tin alloy can be selected according to the temperature to be connected. For example, when a connection is desired at a low temperature, an In—Sn alloy or a Sn—Bi alloy may be employed, and the connection can be made at 150 ° C. or lower. When a material having a high melting point such as Sn-Ag-Cu and Sn-Cu is employed, high reliability tends to be achieved even after being left at high temperature.

  The tin or tin alloy constituting the solder particles 1 may include one or more selected from Ag, Cu, Ni, Bi, Zn, Pd, Pb, Au, P, and B. Among these elements, Ag or Cu may be contained from the following viewpoints. That is, when the solder particles 1 contain Ag or Cu, the melting point of the solder particles 1 can be lowered to about 220 ° C., and the effect of obtaining good conduction reliability by improving the bonding strength with the electrodes. Is played.

  The Cu content of the solder particles 1 is, for example, 0.05 to 10% by mass, and may be 0.1 to 5% by mass or 0.2 to 3% by mass. If the Cu content is 0.05% by mass or more, good solder connection reliability can be easily obtained. On the other hand, if the Cu content is 10% by mass or less, the melting point is lowered and the solder wettability is improved. The connection reliability of the part tends to be good.

  The Ag content of the solder particles 1 is, for example, 0.05 to 10% by mass, and may be 0.1 to 5% by mass or 0.2 to 3% by mass. If the Ag content is 0.05% by mass or more, good solder connection reliability can be easily obtained. On the other hand, if the Ag content is 10% by mass or less, the melting point is lowered and the solder wettability is improved. The connection reliability of the part tends to be good.

(Insulating film)
A thermosetting compound is mentioned as an adhesive agent component which comprises the insulating film 2. FIG. Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acryl compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. Among these, an epoxy compound is preferable from the viewpoint of further improving the curability and viscosity of the insulating resin and further improving the connection reliability.

  The adhesive component may further include a thermosetting agent. Examples of the thermosetting agent include an imidazole curing agent, an amine curing agent, a phenol curing agent, a polythiol curing agent, an acid anhydride, a thermal cation initiator, and a thermal radical generator. These may be used alone or in combination of two or more. Among these, an imidazole curing agent, a polythiol curing agent, or an amine curing agent is preferable because it can be quickly cured at a low temperature. Moreover, since a storage stability becomes high when a thermosetting compound and a thermosetting agent are mixed, a latent hardening agent is preferable. The latent curing agent is preferably a latent imidazole curing agent, a latent polythiol curing agent or a latent amine curing agent. In addition, the said thermosetting agent may be coat | covered with polymeric substances, such as a polyurethane resin or a polyester resin.

  The imidazole curing agent is not particularly limited, and 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-Diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine and 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s- Examples include triazine isocyanuric acid adducts.

  The polythiol curing agent is not particularly limited, and examples thereof include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate. . The solubility parameter of the polythiol curing agent is preferably 9.5 or more, preferably 12 or less. The solubility parameter is calculated by the Fedors method. For example, the solubility parameter of trimethylolpropane tris-3-mercaptopropionate is 9.6, and the solubility parameter of dipentaerythritol hexa-3-mercaptopropionate is 11.4.

  The amine curing agent is not particularly limited, and hexamethylene diamine, octamethylene diamine, decamethylene diamine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraspiro [5.5]. Examples include undecane, bis (4-aminocyclohexyl) methane, metaphenylenediamine, and diaminodiphenylsulfone.

  Examples of the thermal cationic curing agent include iodonium-based cationic curing agents, oxonium-based cationic curing agents, and sulfonium-based cationic curing agents. Examples of the iodonium-based cationic curing agent include bis (4-tert-butylphenyl) iodonium hexafluorophosphate. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate. Examples of the sulfonium-based cationic curing agent include tri-p-tolylsulfonium hexafluorophosphate.

  The thermal radical generator is not particularly limited, and examples thereof include azo compounds and organic peroxides. Examples of the azo compound include azobisisobutyronitrile (AIBN). Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

(flux)
The anisotropic conductive films 10 and 20 preferably contain a flux. Specifically, it is preferable that the adhesive component constituting the anisotropic conductive films 10 and 20 contains the flux and the surface of the solder particles 1 covers the flux. The flux melts the oxide on the solder surface and fuses the particles to each other and improves the wettability of the solder to the electrode.

  As the flux, one that is generally used for soldering or the like can be used. Specific examples include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, hydrazine, an organic acid, and rosin. Can be mentioned. These may be used alone or in combination of two or more.

  Examples of the molten salt include ammonium chloride. Examples of the organic acid include lactic acid, citric acid, stearic acid, glutamic acid, and glutaric acid. Examples of the pine resin include activated pine resin and non-activated pine resin. Pine resin is a rosin composed mainly of abietic acid. By using an organic acid or pine resin having two or more carboxyl groups as the flux, there is an effect that the conduction reliability between the electrodes is further enhanced.

  The melting point of the flux is preferably 50 ° C. or higher, more preferably 70 ° C. or higher, and further preferably 80 ° C. or higher. The melting point of the flux is preferably 200 ° C. or less, more preferably 160 ° C. or less, further preferably 150 ° C. or less, and particularly preferably 140 ° C. or less. When the melting point of the flux is not less than the above lower limit and not more than the above upper limit, the flux effect is more effectively exhibited and the solder particles are more efficiently arranged on the electrode. The range of the melting point of the flux is preferably 80 to 190 ° C, and more preferably 80 to 140 ° C.

  Examples of the flux having a melting point in the range of 80 to 190 ° C. include succinic acid (melting point 186 ° C.), glutaric acid (melting point 96 ° C.), adipic acid (melting point 152 ° C.), pimelic acid (melting point 104 ° C.), suberic acid (melting point) 142 ° C.) and the like, benzoic acid (melting point 122 ° C.), malic acid (melting point 130 ° C.) and the like.

<Method for producing anisotropic conductive film>
The manufacturing method of the anisotropic conductive film 10 will be described with reference to FIGS.

  First, a transfer mold 60 for arranging the solder particles 1 is prepared. 5A is a plan view of the transfer mold 60, and FIG. 5B is a cross-sectional view taken along the line bb shown in FIG. 5A. FIG. 6 is a cross-sectional view showing a state in which the solder particles 1 are accommodated one by one in the plurality of recesses 62 (openings) of the transfer mold 60.

  The recess 62 of the transfer mold 60 is preferably formed in a tapered shape in which the opening area increases from the bottom 62 a side of the recess 62 toward the surface 60 a side of the transfer mold 60. That is, as shown in FIGS. 5A and 5B, the width of the bottom 62a of the recess 62 (the width a in these drawings) is the width of the opening in the surface 60a of the recess 62 (the width in these drawings). Narrower than b). What is necessary is just to set the size (taper angle and depth) of the recessed part 62 according to the size of the solder particle 1 accommodated in the recessed part 62. FIG.

  As a material constituting the transfer mold 60, for example, an inorganic material such as silicon, various ceramics, glass, stainless steel, or the like, and an organic material such as various resins can be used. Among these, from the viewpoint of holding the solder particles 1 in the state where the solder particles 1 are accommodated in the recesses 62, it is preferable to be made of a flexible resin material. The recess 62 of the transfer mold 60 can be formed by a known method such as a photolithographic method. The transfer mold 60 is preferably made of a material having chemical resistance and heat resistance because it may be in contact with a thermosetting resin or the like and heat may be applied to cure the resin.

  By using the transfer mold 60, even if there is a certain width in the particle size distribution of the solder particles 1, a plurality of solder particles 1 having a narrower particle size distribution width can be easily selected and anisotropically conductive. It can be used for the production of the film 10. That is, even if the solder particles 1 smaller than the size of the concave portion 62 of the transfer mold 60 are once accommodated in the concave portion 62, for example, the solder particle 1 falls if the surface on which the concave portion 62 is formed faces downward. Larger solder particles 1 are not accommodated in the recesses 62.

The anisotropic conductive film 10 is manufactured using a transfer mold 60 that can accommodate the solder particles 1 in the recesses 62. That is, the manufacturing method of the anisotropic conductive film 10 includes the following steps in this order.
(A1) A step of accommodating one solder particle 1 in each recess 62 of the transfer mold 60.
(B1) The process of obtaining the 1st film 2b by which the several solder particle 1 was transcribe | transferred by making the film 2a which consists of the said adhesive component contact the side by which the recessed part 62 of the transfer type | mold 60 is provided.
(C1) The anisotropic conductive film 10 is obtained by forming the second film 2d made of the adhesive component on the surface 2c of the first film 2b on the side where the plurality of solder particles 1 are transferred. Process.

  The transfer mold 60 shown in FIG. 7A is in a state after the step (a1), in which one solder particle 1 is accommodated in each of the plurality of recesses 62. While maintaining this state, the transfer mold 60 and the film 2a are brought close to each other with the surface 60a on which the concave portion 62 of the transfer mold 60 is formed facing the film 2a made of the adhesive component (arrow in FIG. 7A). A, B). The film 2a is formed on the surface of the support 65. The support 65 may be a plastic film or a metal foil.

  FIG. 7B shows the state after the step (b1), and the surface 60a on which the concave portion 62 of the transfer mold 60 is formed is brought into contact with the film 2a, so that it is accommodated in the concave portion 62 of the transfer mold 60. The state which the solder particle 1 which had been transferred to the film 2a is shown. By passing through a process (b1), the 1st film 2b comprised by the film 2a and the some solder particle 1 arrange | positioned in the predetermined position of the film 2a is obtained. The first film 2b has a plurality of solder particles 1 exposed on its surface.

  FIG.7 (c) is the state after a process (c1), Comprising: After forming the 2nd film 2d so that the solder particle 1 may be covered on the surface 2c of the 1st film 2b, the support body 65 is used. The removed state is shown. Thereby, the anisotropic conductive film 10 is obtained. The second film 2d may be formed by laminating an insulating film made of an adhesive component on the first film 2b, or the first film 2b is covered with a varnish containing an adhesive component. Then, it may be formed by performing a curing process.

  Next, a method for manufacturing the anisotropic conductive film 20 will be described with reference to FIGS. The anisotropic conductive film 20 has the same structure as the anisotropic conductive film 10 except that a plurality of solder particles 1 are accommodated in place of the single solder particle 1 in each recess 62 of the transfer mold 60. It is manufactured in the same way. Note that the transfer mold 60 shown in FIG. 8 is formed in a tapered shape in which the opening cross section of the recess 62 is circular. That is, the diameter of the bottom of the recess 62 (diameter a in FIG. 8) is set smaller than the diameter of the opening of the recess 62 (diameter b in FIG. 8).

The manufacturing method of the anisotropic conductive film 20 includes the following steps in this order.
(A2) A step of accommodating a plurality of solder particles 1 in each recess 62 of the transfer mold 60.
(B2) The first film 2b on which the particle group 1A composed of a plurality of solder particles 1 is transferred by bringing the film 2a composed of the adhesive component into contact with the side of the transfer mold 60 where the recess 62 is provided. Obtaining.
(C2) The anisotropic conductive film 20 is obtained by forming the second film 2e made of the adhesive component on the surface 2c of the first film 2b on the side where the plurality of particle groups 1A are transferred. Process.

  FIG. 8A is a cross-sectional view schematically showing a state after the step (a2), in which a plurality of solder particles 1 are accommodated in the recesses 62 of the transfer mold 60, and FIG. Is a plan view thereof. What is necessary is just to set suitably the number of the solder particles 1 accommodated in the one recessed part 62 according to the particle size of the solder particle 1, and the size of the recessed part 62, for example, should just be 1-12 pieces, and is 2-8 pieces. Also good.

  As shown in FIG. 9A, a film made of the above adhesive component is formed on the surface 60a on which the recess 62 of the transfer mold 60 is formed while maintaining the state in which the plurality of solder particles 1 are accommodated in the recess 62. The transfer mold 60 and the film 2a are brought closer to 2a (arrows A and B in FIG. 9A). The plurality of solder particles 1 accommodated in the recesses 62 fall from the recesses 62 when the transfer mold 60 is turned upside down from the state shown in FIG. It is preferable to maintain the orientation shown in FIG.

  FIG. 9B shows a state after the step (b2), and is accommodated in the recess 62 of the transfer mold 60 by bringing the surface 60a on which the recess 62 of the transfer mold 60 is formed into contact with the film 2a. The state which the particle group 1A which had been transferred to the film 2a is shown. By passing through a process (b2), the 1st film 2b by which several particle group 1A is arrange | positioned in a predetermined position is obtained. A plurality of convex portions 2e corresponding to the concave portions 62 are formed on the surface 2c side of the first film 2b, and the particle group 1A is embedded in these convex portions 2e. In order to obtain the first film 2b having such a configuration, the adhesive component may be penetrated into the recess 62 in the step (b2). Specifically, it is preferable to apply pressure to fix the plurality of solder particles 1 (particle group 1A) by allowing the adhesive component to enter the recess 62. Furthermore, since the adhesive component easily enters the recess 62 by applying pressure while reducing the pressure, this method is more preferable. Further, instead of the film 2a made of an adhesive component, a varnish containing an adhesive component may be put in the recess 62 and then subjected to a curing treatment.

  FIG. 9C shows a state after the step (c2) in which the support 65 is removed after the second film 2e is formed on the surface 2c of the first film 2b. . Thereby, the anisotropic conductive film 20 is obtained. The second film 2e may be formed by laminating an insulating film made of an adhesive component on the first film 2b, or the first film 2b is covered with a varnish containing an adhesive component. Then, it may be formed by performing a curing process.

<Connection structure>
FIG. 10 is a cross-sectional view schematically showing an enlarged part of the connection structure 50A according to the present embodiment. That is, this figure schematically shows a state in which the electrode 32 of the first circuit member 30 and the electrode 42 of the second circuit member 40 are electrically connected via the solder layer 70 formed by fusion bonding. It is shown. In the present specification, “fusion” is as described above, wherein at least a part of the first metal layer 3a is joined by the solder particles 1 melted by heat, and then is solidified on the surface of the electrode. It means a state where solder is joined. The first circuit member 30 includes a first circuit board 31 and a first electrode 32 disposed on the surface 31a. The second circuit member 40 includes a second circuit board 41 and a second electrode 42 disposed on the surface 41a. The insulating resin layer 55 filled between the circuit members 30 and 40 maintains the state in which the first circuit member 30 and the second circuit member 40 are bonded, and the first electrode 32 and the second electrode. 42 is maintained in an electrically connected state.

  Specific examples of one of the circuit members 30 and 40 include chip components such as an IC chip (semiconductor chip), a resistor chip, a capacitor chip, and a driver IC; a rigid package substrate. These circuit members are provided with circuit electrodes, and generally have many circuit electrodes. Specific examples of the other of the circuit members 30, 40 include a flexible tape substrate having metal wiring, a flexible printed wiring board, and a wiring substrate such as a glass substrate on which indium tin oxide (ITO) is deposited.

  Specific examples of the first electrode 32 or the second electrode 42 include copper, copper / nickel, copper / nickel / gold, copper / nickel / palladium, copper / nickel / palladium / gold, copper / nickel / gold, copper / Palladium, copper / palladium / gold, copper / tin, copper / silver, indium tin oxide and the like. The first electrode 32 or the second electrode 42 can be formed by electroless plating, electrolytic plating, or sputtering.

  FIG. 11 is a cross-sectional view schematically showing a connection structure 50B that is a modification of the connection structure 50A shown in FIG. In the connection structure 50 </ b> B, the solder layer 70 is partially fused to the electrode 32 of the first circuit member 30 and the electrode 42 of the second circuit member 40.

  FIG. 12 is a cross-sectional view schematically showing a connection structure 50C that is a modification of the connection structure 50A shown in FIG. This figure shows a cross section of the electrode part after the first electrode 32 and the second electrode 42 are made of copper, and particularly after being left at a high temperature. A layer 71 made of an intermetallic compound is formed by being left at a high temperature.

  FIG. 13 is a cross-sectional view schematically showing a connection structure 50D that is a modification of the connection structure 50A shown in FIG. This figure shows a cross section of the electrode part after the first electrode 32 and the second electrode 42 are made of copper, and particularly after being left at a high temperature. A layer 71 made of an intermetallic compound is formed by being left at a high temperature. FIG. 13 shows that the layer 71 made of an intermetallic compound is formed thicker by being left at a high temperature as compared with FIG. 12, and reliability is lowered when an impact such as a drop impact is applied.

  FIG. 14 is a cross-sectional view schematically showing a connection structure 50E that is a modification of the connection structure 50A shown in FIG. This figure shows a cross section of the electrode part after the first electrode 32 and the second electrode 42 are made of copper, and particularly after being left at a high temperature. A layer 71 made of an intermetallic compound is formed by being left at a high temperature. FIG. 14 shows a case where the thickness of the solder layer 70 formed between the first electrode 32 and the second electrode 42 is thinner than that in FIG.

  FIG. 15 is a cross-sectional view schematically showing a connection structure 50F that is a modification of the connection structure 50A shown in FIG. This figure shows a case where the first electrode 32 and the second electrode 42 are made of copper, and shows a cross section of the electrode part after FIG. 14 is further left at a high temperature. A layer 71 made of an intermetallic compound is formed by being left at a high temperature. In this case, all the solder layers are changed to intermetallic compounds, indicating that a thin intermetallic compound layer 71 is formed. In FIG. 15, compared with FIG. 12, the thickness of the original solder layer formed between the first electrode 32 or the second electrode 42 is thin, and all the solder layers are changed to intermetallic compounds. However, this indicates that the intermetallic compound layer 71 is thin. In general, when the intermetallic compound layer is thick, the reliability tends to decrease when an impact such as a drop impact is applied. However, all of the solder layer changes to an intermetallic compound and is thin. Even when a drop impact is applied, high reliability can be maintained. The thickness of the intermetallic compound layer 71 is preferably from 0.1 to 10.0 μm, more preferably from 0.3 to 8.0 μm, and even more preferably from 0.5 to 6.0 μm.

<Method for manufacturing connection structure>
A method for manufacturing a connection structure will be described with reference to FIGS. 16 (a) and 16 (b). These drawings are cross-sectional views schematically showing an example of a process of forming the connection structure 50A shown in FIG. First, the anisotropic conductive film 10 shown in FIG. 1 is prepared beforehand, and this is arrange | positioned so that the 1st circuit member 30 and the 2nd circuit member 40 may face (FIG. 16 (a)). At this time, it installs so that the 1st electrode 32 of the 1st circuit member 30 and the 2nd electrode 42 of the 2nd circuit member 40 may oppose. Then, it pressurizes in the thickness direction (the direction of arrow A and arrow B shown in Drawing 16 (a)) of the layered product of these members. At the time of pressurization in the directions of arrows A and B, the whole is heated at least to a temperature higher than the melting point of the solder particles 1 (for example, 130 to 260 ° C.), so that the solder particles 1 are melted and the first electrode 32 and The solder layer 70 is formed by gathering between the second electrodes 42, and then the solder layer 70 is fixed between the first electrode 32 and the second electrode 42 by cooling, so that the first electrode 32 and the second electrode 42 are electrically connected.

  When the insulating film 2 is made of, for example, a thermosetting resin, the thermosetting resin can be cured by heating the whole when pressurizing in the directions of the arrows A and B. As a result, an insulating resin layer 55 made of a cured product of a thermosetting resin is formed between the circuit members 30 and 40.

  FIG. 17 is a cross-sectional view schematically showing a modification of the method for manufacturing the connection structure 50A shown in FIG. In the manufacturing method according to this modification, a part of the solder particles 1 does not contribute to the fusion of the electrodes 32 and 42 and remains in the insulating resin layer 55, but the anisotropic conductive film 10 has a specific Only the solder particles 1 are disposed at the positions, that is, since the density of the solder particles 1 is sufficiently low, the insulation reliability can be maintained high.

  FIG. 18 is a cross-sectional view schematically showing a modification of the manufacturing method of the connection structure 50A shown in FIG. In the manufacturing method according to this modification, substantially all the solder particles 1 become the solder layer 70, and the first electrode 32 of the first circuit member 30 and the second electrode 42 of the second circuit member 40 are formed. Fused. By designing the arrangement of the solder particles 1 in the anisotropic conductive film 10 in advance, the solder particles 1 remaining in the adhesive component without contributing to fusion can be reduced as much as possible. Thereby, the insulation reliability of a connection structure can be improved further.

  FIG. 19 is a cross-sectional view schematically showing a modification of the manufacturing method of the connection structure 50A shown in FIG. This modification is the same as the manufacturing method shown in FIG. 16 except that the anisotropic conductive film 20 is used instead of the anisotropic conductive film 10.

  FIG. 20 is a cross-sectional view schematically showing a modification of the method for manufacturing the connection structure shown in FIG. This modification is the same as the manufacturing method shown in FIG. 17 except that the anisotropic conductive film 20 is used instead of the anisotropic conductive film 10. Part of the particle group 1A does not contribute to the fusion of the electrodes 32 and 42, and the particle group 1A remains as one solder particle 1B in the insulating resin layer 55 due to thermal history. The solder particles 1 are merely arranged at specific positions in the isotropic conductive film 20, that is, the density of the solder particles 1 is sufficiently low, and the particle size of the solder particles 1 is sufficiently small. Since the particle size is also sufficiently small, insulation reliability can be maintained high.

  FIG. 21 is a cross-sectional view schematically showing a modification of the method for manufacturing the connection structure shown in FIG. In the manufacturing method according to this modification, almost all the particle groups 1A become the solder layer 70, and the first electrode 32 of the first circuit member 30 and the second electrode 42 of the second circuit member 40 are fused. doing. By designing the arrangement of the particle group 1A in the anisotropic conductive film 20 in advance, it is possible to reduce the solder particles remaining in the adhesive component without contributing to the fusion as much as possible. Thereby, the insulation reliability of a connection structure can be improved further.

  Examples of the application target of the connection structure according to the above-described embodiments and the modifications thereof include devices such as a liquid crystal display, a personal computer, a mobile phone, a smartphone, and a tablet.

According to this embodiment, even in very small such that the contact area is for example 16～2000Myuemu ² or 25～1600Myuemu ² or 100 to 1000 [mu] m ^2, the connection structure both insulation reliability and conduction reliability is excellent and A manufacturing method thereof is provided.

  Hereinafter, the contents of the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to the following Example.

<Example 1>
[Preparation of anisotropic conductive film]
(Step 1) Classification of solder particles After 100 g of Sn-Bi solder particles (5N Plus, Type 8) having an average particle size of 5.0 μm or less (d90 = 5 μm) are immersed in distilled water, they are ultrasonically dispersed. After filtration through a membrane filter (manufactured by Merck & Co., Inc.) with a diameter of 3 μm, the filtrate was recovered. Thereafter, the filtrate was centrifuged to collect solder particles in the aqueous solution. The collected solder particles were 10 g, and the average particle size was 1.0 μm.

(Step 2) Placement of solder particles on transfer mold Opening diameter 1.0 μmφ, bottom diameter 0.8 μmφ, depth 1 μm (bottom diameter 0.8 μmφ is located at the center of the opening diameter 1.2 μmφ when the concave portion is viewed from the top surface) The transfer mold was prepared in which the recesses (which are to be positioned) were regularly arranged at a space interval of 1.0 μm. A polyimide film (thickness: 100 μm) was used as a transfer type film. Solder particles (average particle diameter: 1.0 μm) after classification were placed in the recesses of the transfer mold.

(Step 3) Preparation of adhesive film 100 g of phenoxy resin (manufactured by Union Carbide, trade name “PKHC”), acrylic rubber (40 parts by mass of butyl acrylate, 30 parts by mass of ethyl acrylate, 30 parts by mass of acrylonitrile, 3 parts by mass of glycidyl methacrylate) Copolymer, molecular weight: 850,000) was dissolved in 400 g of ethyl acetate to obtain a solution. To this solution, 300 g of a liquid epoxy resin (epoxy equivalent 185, manufactured by Asahi Kasei Corporation, trade name “Novacure HX-3941”) containing a microcapsule-type latent curing agent was added and stirred to obtain an adhesive solution. The obtained adhesive solution was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) using a roll coater and dried by heating at 90 ° C. for 10 minutes to obtain a thickness of 4 μm, 6 μm, and An 8 μm adhesive film 1 (corresponding to the film 2a) was produced on the separator.

(Step 4) Transfer of Solder Particles to Adhesive Film Solder particles arranged in a transfer mold recess and the above-mentioned adhesive film 1 are arranged face to face at 50 ° C. and 0.01 MPa (0.1 kgf / cm ² ). The solder particles were transferred to the adhesive film 1 by heating and pressurizing (see FIG. 7B).

(Step 5) Production of anisotropic conductive film The adhesive film 1 obtained in Step 3 is brought into contact with the surface of the adhesive film to which the solder particles have been transferred, and the pressure is 50 ° C. and 0.1 MPa (1 kgf / cm ^2). ) To obtain an anisotropic conductive film in which solder particles having an average particle diameter of 1.0 μm are arranged in layers in a cross-sectional view of the film (see FIG. 7C). Note that an anisotropic conductive film having a thickness of 8 μm, 12 μm, and 16 μm is produced by superimposing 4 μm on a 4 μm thick film and similarly superposing 6 μm on 6 μm and 8 μm on 8 μm. did. The locations where the solder particles in the anisotropic conductive film are to be disposed include a location where one solder particle is disposed and a location where a group of particles composed of a plurality of solder particles are disposed, The average number of solder particles was 1.2.

[Production of connection structure]
(Step 6) Preparation of Chips with Copper Bumps Five types of chips with copper bumps (1.7 × 1.7 mm, thickness: 0.5 mm) shown below were prepared.
(1) Chip C1: area 30 μm × 30 μm, space 30 μm, height: 10 μm, number of bumps 362, number of conductive particles on copper bumps 8
(2) Chip C2: area 15 μm × 15 μm, space 10 μm, height: 10 μm, number of bumps 362, number of conductive particles on copper bumps 8
(3) Chip C3: area 10 μm × 10 μm, space 10 μm, height: 7 μm, number of bumps 362, number of conductive particles on copper bump 4
(4) Chip C4: area 5 μm × 5 μm, space 6 μm, height: 5 μm, number of bumps 362, number of conductive particles on copper bumps 8
(5) Chip C5: area 3 μm × 3 μm, space 3 μm, height: 5 μm, number of bumps 362, number of conductive particles on copper bumps 8

(Step 7) Preparation of substrate with copper bumps Five types of substrates with copper bumps (thickness: 0.7 mm) shown below were prepared.
(1) Substrate D1: area 30 μm × 30 μm, space 30 μm, height: 10 μm, number of bumps 362, number of conductive particles on copper bumps 8
(2) Substrate D2: area 15 μm × 15 μm, space 10 μm, height: 10 μm, number of bumps 362, number of conductive particles on copper bumps 8
(3) Substrate D3: area 10 μm × 10 μm, space 10 μm, height: 7 μm, number of bumps 362, number of conductive particles on copper bump 4
(4) Substrate D4: area 5 μm × 5 μm, space 6 μm, height 5 μm, number of bumps 362, number of conductive particles on copper bumps 8
(5) Substrate D5: area 3 μm × 3 μm, space 3 μm, height: 5 μm, number of bumps 362, number of conductive particles on copper bumps 8

(Step 8) Production of Connection Structure Next, using the produced anisotropic conductive film, a chip with a copper bump (1.7 × 1.7 mm, thickness: 0.5 mm) and a substrate with a copper bump ( The connection structure was obtained by performing connection with thickness: 0.7 mm) according to the procedures of i) to iii) shown below.
i) The separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) on one side of the anisotropic conductive film (2 × 19 mm) is peeled off, the anisotropic conductive film and the substrate with copper bumps are brought into contact with each other at 80 ° C., 0. Affixed at 98 MPa (10 kgf / cm ² ).
ii) The separator was peeled off and the bumps of the chip with copper bumps and the bumps of the substrate with copper bumps were aligned.
iii) The main connection was performed by heating and pressing from above the chip under the conditions of 180 ° C., 40 gf / bump, and 30 seconds. A total of five types of connection structures according to (1) to (5) were produced by the combinations of “chip / anisotropic conductive film / substrate” in the following (1) to (5).
(1) Chip C1 / anisotropic conductive film / substrate D1 having a thickness of 16 μm,
(2) Chip C2 / anisotropic conductive film / substrate D2 with a thickness of 16 μm,
(3) Chip C3 / anisotropic conductive film / substrate D3 having a thickness of 12 μm,
(4) Chip C4 / anisotropic conductive film / substrate D4 with a thickness of 8 μm,
(5) Chip C5 / anisotropic conductive film / substrate D5 having a thickness of 8 μm,

[Evaluation of connection structure]
The conduction resistance test and the insulation resistance test of the obtained connection structure were performed as follows.

(Conduction resistance test-moisture absorption heat resistance test)
Regarding the conduction resistance between the chip (bump) with copper bumps and the substrate (bump) with copper bumps, after the initial value of the conduction resistance and the moisture absorption heat test (temperature, 85 ° C, humidity 85%, left for 100, 500, 1000 hours) Was measured for 20 samples, and the average value thereof was calculated. The evaluation was performed using the above-described connection structure in which the chip C1 and the substrate D1, the chip C2 and the substrate D2, the chip C3 and the substrate D3, the chip C4 and the substrate D4, and the chip C5 and the substrate D5 were connected in combination. The conduction resistance was evaluated from the average value obtained according to the following criteria. The results are shown in Table 1. In addition, it can be said that conduction | electrical_connection resistance is favorable when the reference | standard of following A or B is satisfy | filled 1000 hours after a moisture absorption heat test.
A: Average value of conduction resistance is less than 2Ω B: Average value of conduction resistance is 2Ω or more and less than 5Ω C: Average value of conduction resistance is 5Ω or more and less than 10Ω D: Average value of conduction resistance is 10Ω or more and less than 20Ω E: Conduction resistance The average value of 20Ω or more

(Conduction resistance test-High temperature storage test)
Regarding the conduction resistance between the chip (bump) with copper bump / substrate (bump) with copper bump, the sample was measured before leaving at high temperature and after being left at high temperature (100, 500, 1000 hours at 100 ° C.). . After leaving at high temperature, a drop impact was applied, and the conduction resistance of the sample after the drop impact was measured. For the drop impact, the connection structure was fixed to a metal plate with screws and dropped from a height of 50 cm. After dropping, DC resistance values were measured at the solder joints (4 locations) at the chip corner having the greatest impact, and evaluation was performed assuming that fracture occurred when the measured value increased more than 5 times from the initial resistance. In addition, the measurement of a total of 80 places was performed by 20 samples and 4 places. The results are shown in Table 1. The case where the following criteria A or B were satisfied after 20 drops was evaluated as having good solder connection reliability. In addition, “-” in the table means that the evaluation was not performed.
A: After 20 times of dropping, no solder joints increased by 5 times or more from the initial resistance were found in all 80 locations.
B: After 20 times of dropping, solder connection portions increased by 5 times or more from the initial resistance were observed at 1 to 5 locations.
C: After 20 drops, solder joints increased by 5 times or more from the initial resistance were observed at 6 or more and 20 or less.
D: After 20 drops, solder joints increased by 5 times or more from the initial resistance were observed at 21 or more locations.

(Insulation resistance test)
Regarding the insulation resistance between the chip electrodes, the initial value of the insulation resistance and the value after migration test (temperature, 60 ° C., humidity 90%, 20 V application for 100, 500, 1000 hours) were measured for 20 samples, The ratio of samples with an insulation resistance value of 10 ⁹ Ω or more was calculated among all 20 samples. The evaluation was performed using a connection structure in which the above-described chip C1 and substrate D1, chip C2 and substrate D2, chip C3 and substrate D3, chip C4 and substrate D4, and chip C5 and substrate D5 were connected in combination. The insulation resistance was evaluated from the obtained ratio according to the following criteria. The results are shown in Table 2. In addition, it can be said that insulation resistance is favorable when the following A or B standard is satisfied after 1000 hours of the moisture absorption heat test.
A: Ratio of insulation resistance value of 10 ⁹ Ω or more is 100%
B: Ratio of insulation resistance value 10 ⁹ Ω or more is 90% or more and less than 100% C: Ratio of insulation resistance value 10 ⁹ Ω or more is 80% or more and less than 90% D: Ratio of insulation resistance value 10 ⁹ Ω or more is 50% More than 80% and less than E: Insulation resistance of 10 ⁹ Ω or more is less than 50%

<Example 2>
Similarly to Example 1 (Step 1), 100 g of Sn-Bi solder particles (Type 90, manufactured by 5N Plus, Inc.) having an average particle size of 5.0 μm or less (d90 = 5 μm) were immersed in distilled water, and then subjected to ultrasonic waves. Next, the solution was dispersed and then filtered through a membrane filter of φ1.2 μm (manufactured by Merck & Co., Inc.), and the filtrate was recovered. Thereafter, the filtrate was centrifuged to collect solder particles in the aqueous solution. The collected solder particles were 7 g, and the average particle size was 0.8 μm.
Subsequently, (Step 2) and (Step 3) of Example 1 were performed. At this time, a plurality of solder particles were accommodated in the transfer type recess. In (Step 4), by changing the pressure to 0.1 MPa (1.0 kgf / cm ² ) and applying pressure, the adhesive component of the adhesive film enters the recess, and a plurality of solder particles are applied to the adhesive film. Immobilized (see FIG. 9B).
Subsequently, (Step 5) of Example 1 was performed to obtain an anisotropic conductive film in which particle groups composed of a plurality of solder particles were arranged in a layered manner (see FIG. 9C). The average number of solder particles constituting the particle group was 2.5. In the same manner as in Example 1, the connection structure was evaluated. Table 2 shows the results.

<Example 3>
Similarly to Example 1 (Step 1), 100 g of Sn-Bi solder particles (Type 90, manufactured by 5N Plus, Inc.) having an average particle size of 5.0 μm or less (d90 = 5 μm) were immersed in distilled water, and then subjected to ultrasonic waves. Next, the solution was dispersed and then filtered through a membrane filter (manufactured by Merck & Co., Inc.) having a diameter of 0.8 μm, and the filtrate was recovered. Thereafter, the filtrate was centrifuged to collect solder particles in the aqueous solution. The collected solder particles were 5 g, and the average particle size was 0.6 μm.
Subsequently, (Step 2) and (Step 3) of Example 1 were performed. At this time, a plurality of solder particles were accommodated in the transfer type recess. In (Step 4), by changing the pressure to 0.1 MPa (1.0 kgf / cm ² ) and applying pressure, the adhesive component of the adhesive film enters the recess, and a plurality of solder particles are applied to the adhesive film. Immobilized (see FIG. 9B).
Subsequently, (step e) of Example 1 was performed to obtain an anisotropic conductive film in which particle groups composed of a plurality of solder particles were arranged in a layered manner (see FIG. 9C). The average number of solder particles constituting the particle group was 5.1. In the same manner as in Example 1, the connection structure was evaluated. Table 3 shows the results.

<Example 4>
In Example 1 (Step 2), the shape of the recess of the transfer mold was the same (opening 1.0 μm), and a transfer mold having a density of the recess was reduced by using a space of 2.0 μm. Produced anisotropic conductive films in the same manner as in Example 1, and produced connection structures using these films, and evaluated them. Table 4 shows the results.

<Example 5>
Solder particles obtained in the same manner as in (Step 1) of Example 1 are placed in the transfer mold having an opening diameter of 1.0 μmφ in (Step 2) of Example 1, and the solder particles on the transfer mold are traced by printing. As a result, solder particles having a particle diameter of 1.0 μmφ or less were collected in the recesses. The average particle size of the solder particles that remained without being collected was 1.9 μm.
Subsequently, a recess having an opening diameter of 2.0 μmφ, a bottom diameter of 1.8 μmφ, and a depth of 2 μm (the bottom diameter of 1.8 μmφ is located at the center of the opening diameter of 2.0 μmφ when the recess is viewed from above). A transfer mold regularly arranged with a space interval of 2.0 μm was prepared. A polyimide film (thickness: 100 μm) was used as a transfer type film. Solder particles having an average particle diameter of 1.9 μm were arranged in the concave portion of the transfer mold.
Then, the anisotropic conductive film in which the solder particles are substantially single and arranged in layers is obtained by carrying out the same process as in Step 1 of Example 1 (see FIG. 7C). The average number of solder particles per location where solder particles should be placed in the anisotropic conductive film was 1.1. In the same manner as in Example 1, the connection structure was evaluated. Table 5 shows the results.

<Example 6>
Solder particles obtained in the same manner as in (Step 1) of Example 1 are placed in the transfer mold having an opening diameter of 1.0 μmφ in (Step 2) of Example 1, and the solder particles on the transfer mold are traced by printing. As a result, solder particles having a particle diameter of 1.0 μmφ or less were collected in the recesses. The average particle size of the solder particles that remained without being recovered was 1.6 μm.
Subsequently, a recess having an opening diameter of 2.0 μmφ, a bottom diameter of 1.8 μmφ, and a depth of 2 μm (the bottom diameter of 1.8 μmφ is located at the center of the opening diameter of 2.0 μmφ when the recess is viewed from above). A transfer mold regularly arranged with a space interval of 2.0 μm was prepared. A polyimide film (thickness: 100 μm) was used as a transfer type film. The solder particles having the average particle diameter of 1.6 μm were arranged in the concave portion of the transfer mold.
Subsequently, after performing in the same manner as in (Step 3) of Example 1, in (Step 4) of Example 1, by changing the pressure to 0.1 MPa (1.0 kgf / cm ² ) and pressurizing, The adhesive component of the adhesive film was allowed to enter the recess, and a plurality of solder particles were fixed to the adhesive film (see FIG. 9B).
Subsequently, (Step 5) of Example 1 was performed to obtain an anisotropic conductive film in which particle groups composed of a plurality of solder particles were arranged in a layered manner (see FIG. 9C). The average number of solder particles constituting the particle group was 2.5. In the same manner as in Example 1, the connection structure was evaluated. Table 6 shows the results.

<Example 7>
Solder particles obtained in the same manner as in (Step 1) of Example 1 are placed in the transfer mold having an opening diameter of 1.0 μmφ in (Step 2) of Example 1, and the solder particles on the transfer mold are printed. By tracing, solder particles having a particle size of 1.0 μmφ or less were collected in the recesses. The average particle size of the solder particles that remained without being recovered was 1.3 μm.
Subsequently, a recess having an opening diameter of 2.0 μmφ, a bottom diameter of 1.8 μmφ, and a depth of 2 μm (the bottom diameter of 1.8 μmφ is located at the center of the opening diameter of 2.0 μmφ when the recess is viewed from above). A transfer mold regularly arranged with a space interval of 2.0 μm was prepared. A polyimide film (thickness: 100 μm) was used as a transfer type film. The solder particles having the above average particle diameter of 1.3 μm were arranged in the concave portion of the transfer mold.
After performing in the same manner as in (Step 3) of Example 1, in (Step 4) of Example 1, by changing the pressure to 0.1 MPa (1.0 kgf / cm ² ) and applying pressure, The adhesive component was allowed to enter the recess, and a plurality of solder particles were fixed to the adhesive film (see FIG. 9B).
Subsequently, (Step 5) of Example 1 was performed to obtain an anisotropic conductive film in which particle groups composed of a plurality of solder particles were arranged in a layered manner (see FIG. 9C). The average number of solder particles constituting the particle group was 4.5. In the same manner as in Example 1, the connection structure was evaluated. Table 7 shows the results.

<Example 8>
Similarly to Example 1 (Step 1), 100 g of Sn-Bi solder particles (Type 90, manufactured by 5N Plus, Inc.) having an average particle size of 5.0 μm or less (d90 = 5 μm) were immersed in distilled water, and then subjected to ultrasonic waves. Then, the mixture was filtered and filtered through a membrane filter (manufactured by Merck & Co., Inc.) having a diameter of 5 μm, and the filtrate was recovered. Thereafter, the filtrate was centrifuged to collect solder particles in the aqueous solution. The collected solder particles were 20 g.
The obtained solder particles have an opening diameter of 2.0 μmφ, a bottom diameter of 1.8 μmφ, and a depth of 2 μm (the bottom diameter of 1.8 μmφ is located at the center of the opening diameter of 2.0 μmφ when the concave portion is viewed from the top. ). By tracing the solder particles on the transfer mold by printing, the solder particles having a particle size of 2.0 μmφ or less were collected in the recesses. The average particle size of the solder particles that remained without being collected was 2.8 μm.
Subsequently, a recess having an opening diameter of 3.0 μmφ, a bottom diameter of 2.5 μmφ, and a depth of 3 μm (the bottom diameter of 2.5 μmφ is located at the center of the opening diameter of 3.0 μmφ when the recess is viewed from above). A transfer mold regularly arranged with a space interval of 3.0 μm was prepared. A polyimide film (thickness: 100 μm) was used as a transfer type film. The solder particles having the average particle diameter of 2.8 μm were arranged in the concave portion of the transfer mold.
Then, the anisotropic conductive film in which the solder particles are substantially single and arranged in layers is obtained by carrying out the same process as in Step 1 of Example 1 (see FIG. 7C). The average number of solder particles per place where the solder particles should be placed in the anisotropic conductive film was 1.3. In the same manner as in Example 1, the connection structure was evaluated. Table 8 shows the results.

<Example 9>
Solder particles obtained in the same manner as in (Step 1) of Example 1 are placed in the transfer mold having an opening diameter of 2.0 μmφ in (Step 2) of Example 1, and the solder particles on the transfer mold are traced by printing. Thus, solder particles having a particle diameter of 2.0 μmφ or less were collected in the recesses. The average particle size of the solder particles that remained without being recovered was 2.5 μm.
Subsequently, a recess having an opening diameter of 3.0 μmφ, a bottom diameter of 2.5 μmφ, and a depth of 3 μm (the bottom diameter of 2.5 μmφ is located at the center of the opening diameter of 3.0 μmφ when the recess is viewed from above). A transfer mold regularly arranged with a space interval of 3.0 μm was prepared. A polyimide film (thickness: 100 μm) was used as a transfer type film. The solder particles having an average particle diameter of 2.5 μm were arranged in the concave portion of the transfer mold.
Subsequently, after performing in the same manner as in (Step 3) of Example 1, in (Step 4) of Example 1, by changing the pressure to 0.1 MPa (1.0 kgf / cm ² ) and pressurizing, The adhesive component of the adhesive film was allowed to enter the recess, and a plurality of solder particles were fixed to the adhesive film (see FIG. 9B).
Subsequently, (Step 5) of Example 1 was performed to obtain an anisotropic conductive film in which particle groups composed of a plurality of solder particles were arranged in a layered manner (see FIG. 9C). The average number of solder particles constituting the particle group was 2.3. In the same manner as in Example 1, the connection structure was evaluated. Table 9 shows the results.

<Example 10>
Solder particles obtained in the same manner as in (Step 1) of Example 1 are placed in the transfer mold having an opening diameter of 2.0 μmφ in (Step 2) of Example 1, and the solder particles on the transfer mold are traced by printing. Thus, solder particles having a particle diameter of 2.0 μmφ or less were collected in the recesses. The average particle size of the solder particles remaining without being recovered was 2.3 μm.
Subsequently, a recess having an opening diameter of 3.0 μmφ, a bottom diameter of 2.5 μmφ, and a depth of 3 μm (the bottom diameter of 2.5 μmφ is located at the center of the opening diameter of 3.0 μmφ when the recess is viewed from above). A transfer mold regularly arranged with a space interval of 3.0 μm was prepared. A polyimide film (thickness: 100 μm) was used as a transfer type film. Solder particles having an average particle size of 2.3 μm were arranged in the concave portion of the transfer mold.
Subsequently, after performing in the same manner as in (Step 3) of Example 1, in (Step 4) of Example 1, by changing the pressure to 0.1 MPa (1.0 kgf / cm ² ) and pressurizing, The adhesive component of the adhesive film was allowed to enter the recess, and a plurality of solder particles were fixed to the adhesive film (see FIG. 9B).
Subsequently, (Step 5) of Example 1 was performed to obtain an anisotropic conductive film in which particle groups composed of a plurality of solder particles were arranged in a layered manner (see FIG. 9C). The average number of solder particles constituting the particle group was 4.6. In the same manner as in Example 1, the connection structure was evaluated. Table 10 shows the results.

<Example 11>
Using the anisotropic conductive film produced in Example 8, alignment was performed so that the solder particles formed on the anisotropic conductive film were located between the bumps of the bumps of the chip C5 and the substrate D5, and A connection structure having the configuration according to (5) (chip C5 / an anisotropic conductive film having a thickness of 8 μm / substrate D5) was produced. Otherwise, the connection structure was evaluated in the same manner as in Example 1 (however, the “conducting resistance test-high temperature storage test” was not performed). Table 11 shows the results.

<Example 12>
Using the anisotropic conductive film produced in Example 9, alignment is performed so that the solder particles formed on the anisotropic conductive film are between the bumps of the bumps of the chip C5 and the substrate D5. A connection structure having the configuration according to (5) was produced. Otherwise, the connection structure was evaluated in the same manner as in Example 1 (however, the “conducting resistance test-high temperature storage test” was not performed). Table 11 shows the results.

<Example 13>
Using the anisotropic conductive film produced in Example 10, alignment was performed so that the solder particles formed on the anisotropic conductive film were located between the bumps of the bumps of the chip C5 and the substrate D5, and A connection structure having the configuration according to (5) was produced. Otherwise, the connection structure was evaluated in the same manner as in Example 1 (however, the “conducting resistance test-high temperature storage test” was not performed). Table 11 shows the results.

<Example 14>
100 g of Sn—Bi solder particles (5N Plus, Type 7) having a particle size of 2.0 μm to 14.0 μm or less (d90 = 12 μm) are sieved with a high-precision electroformed sieve (As One Corporation, trade name) having an opening size of 4 μm. Over time, those that did not pass were collected. Subsequently, the collected solder particles were sieved with a high-precision electroformed sieve having an opening size of 6 μm (As One Corporation, trade name), and the solder particles that passed through the sieve were collected.

The obtained solder particles have an opening diameter of 3.0 μmφ, a bottom diameter of 2.5 μmφ, and a depth of 3 μm (the bottom diameter of 2.5 μmφ is located at the center of the opening diameter of 3.0 μmφ when the concave portion is viewed from the top. ) Was placed in a transfer mold having a recess. Then, the solder particles on the transfer mold were traced by printing to collect solder particles having a particle size of 3.0 μmφ or less in the recesses. The average particle size of the solder particles that remained without being recovered was 4.6 μm.
Subsequently, a recess having an opening diameter of 5.0 μmφ, a bottom diameter of 4.0 μmφ, and a depth of 5 μm (the bottom diameter of 4.0 μmφ is located at the center of the opening diameter of 5.0 μmφ when the recess is viewed from the top). A transfer mold regularly arranged with a space interval of 5.0 μm was prepared. A polyimide film (thickness: 100 μm) was used as a transfer type film. The solder particles having the average particle diameter of 4.6 μm were arranged in the concave portion of the transfer mold.

Then, the anisotropic conductive film in which the solder particles are substantially single and arranged in layers is obtained by carrying out the same process as in Step 1 of Example 1 (see FIG. 7C). The average number of solder particles per location where the solder particles should be disposed in the anisotropic conductive film was 1.2. In the same manner as in Example 1, the following connection structures (1) to (4) were evaluated. Table 12 shows the results.
(1) Chip C1 / 16 μm thick anisotropic conductive film / substrate D1,
(2) Chip C2 / 16 μm thick anisotropic conductive film / substrate D2,
(3) Chip C3 / 12 μm thick anisotropic conductive film / substrate D3,
(4) Chip C4 / 8 μm thick anisotropic conductive film / substrate D4,

<Example 15>
100 g of Sn—Bi solder particles (5N Plus, Type 7) having a particle size of 2.0 μm to 14.0 μm or less (d90 = 12 μm) are sieved with a high-precision electroformed sieve (As One Corporation, trade name) having an opening size of 4 μm. Over time, those that did not pass were collected. Subsequently, the collected solder particles were passed through a high-precision electroformed sieve (As One Co., Ltd., trade name) with an opening size of 5 μm, and the solder particles that passed through the sieve were collected.

The obtained solder particles have an opening diameter of 3.0 μmφ, a bottom diameter of 2.5 μmφ, and a depth of 3 μm (the bottom diameter of 2.5 μmφ is located at the center of the opening diameter of 3.0 μmφ when the concave portion is viewed from the top. ) Was placed in a transfer mold having a recess. Then, the solder particles on the transfer mold were traced by printing to collect solder particles having a particle size of 3.0 μmφ or less in the recesses. The average particle size of the solder particles remaining without being collected was 3.7 μm.
Subsequently, a recess having an opening diameter of 5.0 μmφ, a bottom diameter of 4.0 μmφ, and a depth of 5 μm (the bottom diameter of 4.0 μmφ is located at the center of the opening diameter of 5.0 μmφ when the recess is viewed from the top). A transfer mold regularly arranged with a space interval of 5.0 μm was prepared. A polyimide film (thickness: 100 μm) was used as a transfer type film. The solder particles having the average particle diameter of 3.7 μm were arranged in the concave portion of the transfer mold.

Subsequently, after performing in the same manner as in (Step 3) of Example 1, in (Step 4) of Example 1, by changing the pressure to 0.1 MPa (1.0 kgf / cm ² ) and pressurizing, The adhesive component of the adhesive film was allowed to enter the recess, and a plurality of solder particles were fixed to the adhesive film (see FIG. 9B).
Subsequently, (Step 5) of Example 1 was performed to obtain an anisotropic conductive film in which particle groups composed of a plurality of solder particles were arranged in a layered manner (see FIG. 9C). The average number of solder particles constituting the particle group was 3.4. In the same manner as in Example 1, the connection structure having the configuration according to (1) to (4) was evaluated. Table 13 shows the results.

<Example 16>
100 g of Sn—Bi solder particles (5N Plus, Type 7) having a particle size of 2.0 μm to 14.0 μm or less (d90 = 12 μm) are sieved with a high-precision electroformed sieve (As One Corporation, trade name) having an opening size of 4 μm. Over time, those that did not pass were collected. Subsequently, the collected solder particles were passed through a high-precision electroformed sieve (As One Co., Ltd., trade name) with an opening size of 5 μm, and the solder particles that passed through the sieve were collected.

The obtained solder particles have an opening diameter of 3.0 μmφ, a bottom diameter of 2.5 μmφ, and a depth of 3 μm (the bottom diameter of 2.5 μmφ is located at the center of the opening diameter of 3.0 μmφ when the concave portion is viewed from the top. ) Was placed in a transfer mold having a recess. Then, the solder particles on the transfer mold were traced by printing to collect solder particles having a particle size of 3.0 μmφ or less in the recesses. The average particle size of the solder particles remaining without being collected was 3.2 μm.
Subsequently, a recess having an opening diameter of 5.0 μmφ, a bottom diameter of 4.0 μmφ, and a depth of 5 μm (the bottom diameter of 4.0 μmφ is located at the center of the opening diameter of 5.0 μmφ when the recess is viewed from the top). A transfer mold regularly arranged with a space interval of 5.0 μm was prepared. A polyimide film (thickness: 100 μm) was used as a transfer type film. The solder particles having the above average particle diameter of 3.2 μm were arranged in the concave portion of the transfer mold.

Subsequently, after performing in the same manner as in (Step 3) of Example 1, in (Step 4) of Example 1, by changing the pressure to 0.1 MPa (1.0 kgf / cm ² ) and pressurizing, The adhesive component of the adhesive film was allowed to enter the recess, and a plurality of solder particles were fixed to the adhesive film (see FIG. 9B).
Subsequently, (Step 5) of Example 1 was performed to obtain an anisotropic conductive film in which particle groups composed of a plurality of solder particles were arranged in a layered manner (see FIG. 9C). The average number of solder particles constituting the particle group was 4.2. In the same manner as in Example 1, the connection structure having the configuration according to (1) to (4) was evaluated. Table 14 shows the results.

<Example 17>
Example 14 except that a transfer mold having recesses at positions corresponding to the positions and sizes of the bumps was used instead of the transfer mold having recesses regularly arranged with a space of 5.0 μm. In the same manner, an anisotropic conductive film was produced. FIG. 22 is a plan view schematically showing the relationship between the positions of the solder particles of the anisotropic conductive film and the positions of the bumps (size 30 μm × 30 μm). FIG. 23 is a plan view schematically showing the relationship between the position of the solder particles of the anisotropic conductive film and the position of the bump (size 15 μm × 15 μm). FIG. 24 is a plan view schematically showing the relationship between the position of the solder particles of the anisotropic conductive film and the position of the bump (size 10 μm × 10 μm). FIG. 25 is a plan view schematically showing the relationship between the position of the solder particles of the anisotropic conductive film and the position of the bump (size 5 μm × 5 μm).
Using the produced anisotropic conductive film, the connection structures according to (1) to (4) were evaluated in the same manner as in Example 1. Table 15 shows the results.

<Example 18>
Example 15 except that a transfer mold having recesses at positions corresponding to the positions and sizes of the bumps was used instead of the transfer mold in which the recesses were regularly arranged at a space interval of 5.0 μm. Similarly, an anisotropic conductive film was produced (see FIGS. 22 to 25). Using the produced anisotropic conductive film, the connection structures according to (1) to (4) were evaluated in the same manner as in Example 1. Table 16 shows the results.

<Example 19>
Example 16 is different from the transfer mold in which the concave portions are regularly arranged at a space interval of 5.0 μm, except that a transfer die having concave portions at positions corresponding to the positions and sizes of the bumps is used. Similarly, an anisotropic conductive film was produced (see FIGS. 22 to 25). Using the produced anisotropic conductive film, the connection structures according to (1) to (4) were evaluated in the same manner as in Example 1. Table 17 shows the results.

<Example 20>
100 g of Sn—Bi solder particles (5N Plus, Type 7) having a particle size of 2.0 μm to 14.0 μm or less (d90 = 12 μm) are sieved with a high-precision electroformed sieve (As One Co., Ltd., trade name) having an opening size of 5 μm. The thing that did not pass was collected. Subsequently, the collected solder particles were passed through a high-precision electroformed sieve (As One Co., Ltd., trade name) with an opening size of 7 μm, and the solder particles that passed through the sieve were collected. The average particle diameter of the collected solder particles was 5.7 μm.

Subsequently, a recess having an opening diameter of 10.0 μmφ, a bottom diameter of 8.0 μmφ, and a depth of 7 μm (the bottom diameter of 8.0 μmφ is located at the center of the opening diameter of 10.0 μmφ when the recess is viewed from above). Transfer molds provided at positions corresponding to the centers of the bumps of the chips C1, C2, and C3 were prepared. A polyimide film (thickness: 100 μm) was used as a transfer type film. The solder particles having the above average particle diameter of 5.7 μm were arranged in the concave portion of the transfer mold.
Subsequently, after performing in the same manner as in (Step 3) of Example 1, in (Step 4) of Example 1, by changing the pressure to 0.1 MPa (1.0 kgf / cm ² ) and pressurizing, The adhesive component of the adhesive film was allowed to enter the recess, and a plurality of solder particles were fixed to the adhesive film (see FIG. 9B).
Subsequently, (Step 5) of Example 1 was performed to obtain an anisotropic conductive film in which particle groups composed of a plurality of solder particles were arranged in a layered manner (see FIG. 9C). The average number of solder particles constituting the particle group was 3.5. In the same manner as in Example 1, the connection structure having the configuration according to (1) to (3) was evaluated. Table 18 shows the results.

<Example 21>
While using the solder particles having an average particle diameter of 4.6 μm obtained in Example 14, an anisotropic conductive film was produced using the same transfer mold as in Example 20. The average number of solder particles constituting the particle group was 5.7. In the same manner as in Example 1, the connection structure having the configuration according to (1) to (3) was evaluated. Table 19 shows the results.

<Example 22>
While using the solder particles having an average particle diameter of 3.7 μm obtained in Example 15, an anisotropic conductive film was produced using the same transfer mold as in Example 20. The average number of solder particles constituting the particle group was 9.5. In the same manner as in Example 1, the connection structures according to (1) to (3) were evaluated. Table 20 shows the results.

<Example 23>
100 g of Sn—Bi solder particles (5N Plus, Type 6) having a particle size of 5.0 μm to 23.0 μm or less (d90 = 16 μm) are sieved with a high-precision electroformed sieve (As One Corporation, trade name) having an opening size of 5 μm. The thing that did not pass was collected. Subsequently, the collected solder particles were passed through a high-precision electroformed sieve (As One Co., Ltd., trade name) with an opening size of 7 μm, and the solder particles that passed through the sieve were collected. The average particle size of the collected solder particles was 6.7 μm.

Subsequently, a recess having an opening diameter of 10.0 μmφ, a bottom diameter of 8.0 μmφ, and a depth of 7 μm (the bottom diameter of 8.0 μmφ is located at the center of the opening diameter of 10.0 μmφ when the recess is viewed from above). Transfer molds provided at positions corresponding to the centers of the bumps of the chips C1 and C2 were prepared. A polyimide film (thickness: 100 μm) was used as a transfer type film. The solder particles having the above average particle diameter of 6.7 μm were arranged in the concave portion of the transfer mold.
Subsequently, after performing in the same manner as in (Step 3) of Example 1, in (Step 4) of Example 1, by changing the pressure to 0.1 MPa (1.0 kgf / cm ² ) and pressurizing, The adhesive component of the adhesive film was allowed to enter the recess, and a plurality of solder particles were fixed to the adhesive film (see FIG. 9B).
Subsequently, (Step 5) of Example 1 was performed to obtain an anisotropic conductive film in which particle groups composed of a plurality of solder particles were arranged in a layered manner (see FIG. 9C). The average number of solder particles constituting the particle group was 4.2. In the same manner as in Example 1, the connection structure having the configuration according to (1) and (2) was evaluated. Table 21 shows the results.

<Example 24>
While using the solder particles having an average particle diameter of 4.6 μm obtained in Example 14, an anisotropic conductive film was produced using the same transfer mold as that in Example 23. The average number of solder particles constituting the particle group was 6.5. In the same manner as in Example 1, the connection structure having the configuration according to (1) and (2) was evaluated. Table 22 shows the results.

<Example 25>
While using the solder particles having an average particle diameter of 3.7 μm obtained in Example 15, an anisotropic conductive film was produced using the same transfer mold as in Example 23. The average number of solder particles constituting the particle group was 9.3. In the same manner as in Example 1, the connection structure having the configuration according to (1) and (2) was evaluated. Table 23 shows the results.

<Comparative Example 1>

A solder particle-containing anisotropic conductive paste containing the following components in the following parts by mass was prepared.
(Polymer): 12 parts by mass (thermosetting compound): 29 parts by mass (high dielectric constant curing agent): 20 parts by mass (thermosetting agent): 11.5 parts by mass (flux): 2 parts by mass (solder particles) 34 parts by mass

(polymer)
Synthesis of reaction product (polymer A) of bisphenol F with 1,6-hexanediol diglycidyl ether and bisphenol F type epoxy resin:
72 parts by mass of bisphenol F (containing 4,4′-methylene bisphenol, 2,4′-methylene bisphenol and 2,2′-methylene bisphenol in a mass ratio of 2: 3: 1), 1,6-hexanediol 70 parts by mass of glycidyl ether and 30 parts by mass of a bisphenol F type epoxy resin (“EPICLON EXA-830CRP” manufactured by DIC Corporation) were placed in a three-necked flask and dissolved at 150 ° C. under a nitrogen flow. Thereafter, 0.1 part by mass of tetra-n-butylsulfonium bromide, which is an addition reaction catalyst between a hydroxyl group and an epoxy group, was added, and an addition polymerization reaction was performed at 150 ° C. for 6 hours under a nitrogen flow. )

(Thermosetting compound): Resorcinol type epoxy compound, “EX-201” manufactured by Nagase ChemteX Corporation
(High dielectric constant curing agent): Pentaerythritol tetrakis (3-mercaptobutyrate)

(Thermosetting agent): “Karenz MT PE1” manufactured by Showa Denko KK

(Flux): Adipic acid, Wako Pure Chemical Industries, Ltd.

(Solder particles):
200 g of SnBi solder particles (“ST-3” manufactured by Mitsui Mining & Smelting Co., Ltd.), 40 g of adipic acid and 70 g of acetone are weighed in a three-necked flask, and then the hydroxyl group on the surface of the solder particle body and the carboxyl of adipic acid 0.3 g of dibutyltin oxide which is a dehydration condensation catalyst with a group was added and reacted at 60 ° C. for 4 hours. Thereafter, the solder particles were collected by filtration. The collected solder particles, 50 g of adipic acid, 200 g of toluene, and 0.3 g of paratoluenesulfonic acid were weighed in a three-necked flask and reacted at 120 ° C. for 3 hours while evacuating and refluxing. . At this time, the reaction was carried out while removing water produced by dehydration condensation using a Dean-Stark extraction device. Thereafter, the solder particles were collected by filtration, washed with hexane, and dried. Thereafter, the obtained solder particles were crushed with a ball mill, and then a sieve was selected so as to obtain a predetermined CV value. The average particle diameter of the obtained SnBi solder particles was 4 μm, and the CV value was 7%.

A chip with a copper bump and a substrate with a copper bump were prepared in the same manner as in (Step 6) and (Step 7) of Example 1. A connection structure having the following structure was produced. A solder particle-containing anisotropic conductive paste and a chip are formed on the upper part of the substrate. The bumps of the chip with the copper bump and the bump of the substrate with the copper bump were aligned. The main connection was performed by heating and pressing from above the chip under the conditions of 180 ° C., 4 gf / bump, and 30 seconds. A total of five types of connection structures according to (1) to (5) were produced by the combinations of “chip / solder particle-containing anisotropic conductive paste / substrate” in the following (1) to (5). In the same manner as in Example 1, the connection structure was evaluated. Table 24 shows the results.
(1) Chip C1 / 16 μm thick (on copper bump) solder particle-containing anisotropic conductive paste / substrate D1,
(2) Solder particle-containing anisotropic conductive paste / substrate D2 having a thickness of chip C2 / 16 μm (on the copper bump),
(3) Solder particle-containing anisotropic conductive paste / substrate D3 having a thickness of chip C3 / 12 μm (on the copper bump),
(4) Solder particle-containing anisotropic conductive paste / substrate D4 having a thickness of chip C4 / 8 μm (on the copper bumps),
(5) Chip C5 / 8 μm thick (on copper bump) solder particle-containing anisotropic conductive paste / substrate D5,

<Comparative example 2>

  Instead of 200 g of SnBi solder particles (“ST-3” manufactured by Mitsui Kinzoku Mining Co., Ltd.) used in Comparative Example 1, 200 g of SnBi solder particles (“ST-5” manufactured by Mitsui Kinzoku Mining Co., Ltd.) were used, and the average particles were used. The connection structure was evaluated in the same manner as Comparative Example 1 except that SnBi solder particles having a diameter of 6 μm and a CV value of 10% were used. Table 25 shows the results.

DESCRIPTION OF SYMBOLS 1 ... Solder particle, 1A ... Particle group, 2 ... Insulating film (adhesive component), 2a ... Film (adhesive component), 2b ... First film, 2c ... First film surface, 2d ... Second Film (adhesive component), 10, 20 ... anisotropic conductive film, 30 ... first circuit member, 31 ... first substrate, 32 ... first electrode, 40 ... second circuit member, 41 ... 2nd board | substrate, 42 ... 2nd electrode, 50A-50F ... connection structure, 55 ... insulating resin layer (adhesive agent component or its hardened | cured material), 60 ... transcription | transfer type, 62 ... recessed part (opening part), 70 ... Solder layer, 71 ... intermetallic compound layer.

Claims (15)

A method for producing an anisotropic conductive film, comprising:
(A) storing one or a plurality of solder particles in a plurality of openings provided in the transfer mold, and
(B) obtaining a first film to which the solder particles are transferred by bringing an insulating adhesive component into contact with the side of the transfer mold on which the opening is provided;
(C) a step of obtaining an anisotropic conductive film by forming a second film comprising an adhesive component having insulating properties on the surface of the first film on the side to which the solder particles are transferred; ,
The manufacturing method of an anisotropic conductive film containing these in this order.   The manufacturing method according to claim 1, wherein the solder particles are exposed on the surface of the first film obtained in the step (b).   The manufacturing method according to claim 1, wherein in the step (b), the solder particles are embedded on the surface side of the first film by allowing the adhesive component to penetrate into the opening. .   (B) A process is a manufacturing method as described in any one of Claims 1-3 which has the step which hardens the said adhesive agent component after the transfer of the said solder particle. An anisotropic conductive film comprising:
An insulating film comprising an adhesive component having insulating properties;
A plurality of solder particles disposed in the insulating film;
Including
In the longitudinal cross-section of the anisotropic conductive film, one solder particle or a group of particles composed of a plurality of the solder particles is arranged in a lateral direction in a state of being separated from one adjacent solder particle or the group of particles. An anisotropic conductive film is disposed.   The anisotropic conductive film according to claim 5, wherein the particle groups are regularly arranged in a cross section of the anisotropic conductive film.   The anisotropic conductive film of Claim 5 or 6 whose average particle diameter of the said solder particle is 0.6-15 micrometers.   The anisotropic conductive film according to claim 5, wherein the solder particles include tin or a tin alloy.   The said solder particle consists of In-Sn alloy, In-Sn-Ag alloy, Sn-Bi alloy, Sn-Bi-Ag alloy, Sn-Ag-Cu alloy, or Sn-Cu alloy, Any one of Claims 5-8 An anisotropic conductive film according to claim 1.   The anisotropic conductive film as described in any one of Claims 5-9 with which the surface of the said solder particle is coat | covered with the flux component. Providing a first circuit member having a first substrate and a first electrode provided on the first substrate;
Providing a second circuit member having a second electrode electrically connected to the first electrode;
The surface of the first circuit member having the first electrode and the surface of the second circuit member having the second electrode according to any one of claims 5 to 10. Disposing an anisotropic conductive film;
By heating the laminated body including the first circuit member, the anisotropic conductive film, and the second circuit member to a temperature equal to or higher than the melting point of the solder particles in a pressed state in the thickness direction of the laminated body. Electrically connecting the first electrode and the second electrode via solder and bonding the first circuit member and the second circuit member;
A method for manufacturing a connection structure including: A first circuit member having a first substrate and a first electrode provided on the first substrate;
A second circuit member having a second electrode electrically connected to the first electrode;
A solder joint interposed between the first electrode and the second electrode;
An insulating resin layer provided between the first circuit member and the second circuit member, and being bonded to the first circuit member and the second circuit member;
A connection structure comprising:   The at least one of the first electrode and the second electrode is made of a material selected from the group consisting of copper, nickel, palladium, gold, silver and alloys thereof, and indium tin oxide. The connection structure described. At least one of the first electrode and the second electrode is made of copper,
The connection structure according to claim 12 or 13, wherein the first electrode and the second electrode are connected via a layer made of an intermetallic compound.   The connection structure according to claim 14, wherein the layer made of the intermetallic compound has a thickness of 0.1 to 10.0 μm.

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