JP2018129369A - Connection structure, manufacturing method thereof, manufacturing method of electrode with terminal, and conductive particle, kit and transfer mold used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a connection structure having both of excellent insulation reliability and conduction reliability even in a case where a connection spot of circuit members that are to be electrically connected with each other, has a very small area.SOLUTION: A manufacturing method of a connection structure includes: preparing multiple conductive particles each having a surface consisting of a first metal; accommodating the conductive particles in multiple openings of a transfer mold; forming a second metal layer consisting of a second metal including tin or tin alloy on a part of surfaces of the conductive particles that are accommodated in the openings, by sputtering; disposing multiple conductive particles in which the second metal layer is formed, on a surface of a first electrode; fusing the conductive particles to the first electrode by heating the conductive particles at a higher temperature than a melting point of the second metal; forming an insulation resin layer between a first circuit member including the first electrode and a second circuit member including a second electrode; and electrically connecting the first and second electrodes to each other and bonding the first and second circuit members together by pressing and heating.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a connection structure and a method for manufacturing the same, a method for manufacturing an electrode with a terminal, and conductive particles, a kit, and a transfer mold used therefor.

  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 recent high definition of liquid crystal display, the metal bumps which are circuit electrodes of the liquid crystal driving IC are narrowed in pitch and area, so that the circuit where 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 conductive particles flow out between adjacent circuit electrodes, the number of conductive particles in the anisotropic conductive adhesive trapped between the metal bumps and the glass panel decreases, and the connection resistance between the facing circuit electrodes increases. There is a risk of poor connection. 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.

Japanese Patent No. 4777385 Japanese Patent No. 3869785 JP 2014-17213 A

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.

  The present invention has been made in view of the above problems, and a connection structure excellent in both insulation reliability and conduction reliability even when connection portions of circuit members to be electrically connected to each other are very small, and the connection structure thereof An object is to provide a manufacturing method. Moreover, an object of this invention is to provide the manufacturing method of the electrode with a terminal useful for manufacturing the said connection structure, and the electroconductive particle used for this, a kit, and a transfer type | mold.

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.

The present invention has been made based on the above findings of the present inventors. The present invention provides a method for manufacturing a connection structure. That is, the manufacturing method of the connection structure according to the present invention includes the following steps.
Preparing 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;
Prepare a plurality of conductive particles having a surface made of the first metal.
Housing the conductive particles in a transfer-type opening having a plurality of openings;
Forming a second metal layer made of a second metal containing tin or a tin alloy by sputtering on at least a part of the surface of the conductive particles accommodated in the opening of the transfer mold;
Disposing a plurality of conductive particles on which the second metal layer is formed on the surface of the first electrode;
The conductive particles are fused to the first electrode by heating the plurality of conductive particles arranged on the surface of the first electrode to a temperature higher than the melting point of the second metal.
A surface of the first circuit member having the first electrode fused with the conductive particles and a surface of the second circuit member having the second circuit. Form an insulating resin layer between them.
Conductive particles between the first electrode and the second electrode by heating the laminate including the first circuit member, the insulating resin layer, and the second circuit member while pressing the laminate in the thickness direction of the laminate. And electrically connecting the first circuit member and the second circuit member.

  According to the manufacturing method of the connection structure, a plurality of conductive particles are fused to the surface of the first electrode, so that only between the first electrode and the second electrode to be electrically connected to each other. Conductive particles can be placed. Thereby, even if the connection location of the 1st electrode and the 2nd electrode is minute, the connection structure excellent in both insulation reliability and conduction reliability can be manufactured sufficiently efficiently and stably. . That is, the conductive particles fused to the surface of the first electrode serve as bumps (connection protrusions), so that innumerable conductive particles contained in the anisotropic conductive material have insulating properties as in the prior art. By flowing out between adjacent electrodes to be secured, it is possible to highly suppress the occurrence of a short circuit between the electrodes.

The present invention provides a method of manufacturing an electrode with a terminal. That is, the manufacturing method of the electrode with a terminal which concerns on this invention includes the following processes.
Prepare a circuit member having a substrate and electrodes provided on the substrate.
Prepare a plurality of conductive particles having a surface made of the first metal.
Housing the conductive particles in a transfer-type opening having a plurality of openings;
Forming a second metal layer made of a second metal containing tin or a tin alloy by sputtering on at least a part of the surface of the conductive particles accommodated in the opening of the transfer mold;
Arranging a plurality of conductive particles on which the second metal layer is formed on the surface of the electrode;
-The conductive particles are fused to the electrode by heating the plurality of conductive particles arranged on the surface of the electrode to a temperature higher than the melting point of the second metal.

  According to the method for manufacturing an electrode with a terminal, the conductive particles can serve as bumps (connection protrusions) by fusing a plurality of conductive particles to the surface of the electrode. As a result, a connection structure having both excellent insulation reliability and conduction reliability can be obtained even if the connection location between the electrode and the electrode of another circuit member to be electrically connected to the circuit member is very small. Useful for efficient and stable production.

  In the present invention, a plurality of conductive particles may be disposed on the electrode (first electrode), and a transfer mold may be used to fuse these particles at the position. That is, the method for manufacturing a connection structure or the method for manufacturing an electrode with a terminal according to the present invention includes a transfer having a plurality of openings at positions corresponding to positions where a plurality of conductive particles are arranged in an electrode (first electrode). Providing a mold; further comprising containing conductive particles in a plurality of openings, and by superimposing a circuit member (first circuit member) and a transfer mold on the surface of the electrode (first electrode); The conductive particles respectively accommodated in the openings of the transfer mold are arranged, and the plurality of conductive particles are brought to a temperature higher than the melting point of the metal in a state where the circuit member (first circuit member) and the transfer mold are overlapped. The conductive particles may be fused to the electrode (first electrode) by heating.

  The present invention provides the above transfer mold. That is, the transfer mold according to the present invention is used in the method for manufacturing the connection structure or the method for manufacturing the electrode with terminal, and is located at a position corresponding to the position where a plurality of conductive particles are arranged on the electrode surface. It has a plurality of openings. According to this transfer type, a plurality of fine conductive particles (for example, a particle size of 2.3 to 25 μm) can be efficiently arranged and fused at predetermined positions on the electrode surface.

  The opening of the transfer mold is preferably formed in a tapered shape in which the opening area increases from the back side of the opening toward the surface of the transfer mold. The transfer mold is preferably made of a flexible resin material. By adopting these configurations, even if there is a certain width in the particle size distribution of the conductive particles, a plurality of conductive particles having a narrower particle size distribution width can be easily selected and placed on the electrode surface. Can do. That is, even if the conductive particles that are smaller than the size of the transfer-type opening are once accommodated in the opening, for example, if the surface on which the opening is formed faces downward, the conductive particle falls, whereas the conductive particle is larger than the size of the opening The conductive particles are not accommodated in the opening. Conductive particles that fit the size of the opening fit into the opening, and with this state maintained, the surface on which the transfer-type opening is formed is brought into contact with the electrode surface, so that a plurality of conductive particles are applied to the electrode surface. It can arrange | position according to the formation pattern of an opening part.

  This invention provides the electrically-conductive particle used in the manufacturing method of the said connection structure, or the manufacturing method of the said electrode with a terminal. That is, the conductive particles according to the present invention have a surface made of the first metal and a second metal layer made of the second metal containing tin or a tin alloy formed so as to cover at least a part of the surface. The melting point of the second metal is, for example, 120 to 250 ° C. In a state where the plurality of conductive particles are arranged on the electrode surface, the plurality of conductive particles are respectively melted at predetermined positions on the electrode surface by heating to a temperature higher than the melting point of the first metal constituting the surface of the conductive particles. Worn. The average particle diameter of the conductive particles of the present invention is, for example, 2.3 to 25 μm.

  The present invention provides a connection structure. That is, the connection structure according to the present invention includes a first circuit member having a first substrate and a first electrode provided on the first substrate; and electrically connected to the first electrode. A second circuit member having a second electrode, the conductive particles interposed between the first electrode and the second electrode and fused to at least the first electrode, and the first circuit An insulating resin layer is provided between the member and the second circuit member, and is bonded to the first circuit member and the second circuit member. According to this connection structure, since the conductive particles fused to the surface of the first electrode serve as bumps (connection protrusions), the connection location between the first electrode and the second electrode is very small. Even so, both insulation reliability and conduction reliability can be achieved to a sufficiently high level.

  The present invention provides a kit for manufacturing an electrode with a terminal. That is, the kit according to the present invention includes the conductive particles and a transfer mold having a plurality of openings at positions corresponding to positions where the plurality of conductive particles on the electrode surface are arranged. According to this kit, a plurality of fine conductive particles (for example, a particle size of 2.3 to 25 μm) can be efficiently arranged at a predetermined position on the electrode surface.

  The present invention provides a transfer mold used in the method for manufacturing the connection structure or the method for manufacturing the electrode with terminal. That is, the transfer mold according to the present invention has a plurality of openings at positions corresponding to positions where a plurality of conductive particles are arranged on the electrode surface.

  In the present invention, the conductive particles preferably include base particles and a first metal layer made of a first metal that covers the surface of the base particles. In this case, it is preferable that the melting point of the first metal layer is higher than the melting point of the second metal layer. In a state where the plurality of conductive particles on which the second metal layer is formed are arranged on the electrode surface, the first metal is heated to a temperature lower than the melting point of the first metal layer and higher than the melting point of the second metal layer. The state in which the layer covers the base particles is sufficiently maintained, whereby excellent connection reliability is obtained, and a plurality of conductive particles are fused by the second metal layer melted at a predetermined position on the electrode surface. be able to.

  The particle size of the substrate particles may be, for example, 2 to 10 μm. The substrate particles are preferably made of a resin. The base particles made of resin easily absorb the impact when an impact is applied to the connection portion of the circuit connection body, and contribute to the improvement of the connection reliability of the circuit connection body.

  When the conductive particles have the first metal layer, the first metal layer is preferably a layer containing nickel or a nickel alloy from the viewpoint of high melting point and conductivity. From the viewpoint of stably remaining the first metal layer containing nickel or a nickel alloy and obtaining sufficiently excellent connection reliability, the nickel content of the first metal layer is preferably 85 to 98% by mass.

  The second metal layer made of the second metal containing tin or tin alloy preferably has a tin content of 30 to 100% by mass from the viewpoint of a low melting point. As a metal constituting the second metal layer, a tin alloy such as In—Sn, In—Sn—Ag, Sn—Bi, Sn—Bi—Ag, Sn—Ag—Cu, or Sn—Cu may be employed. The second metal layer is formed by sputtering. The following effects are produced by forming the second metal layer on a part of the first metal layer by sputtering. That is, by melting the second metal layer in a state where the plurality of conductive particles are arranged on the electrode, the plurality of conductive particles can be fused to a predetermined position of the electrode, thereby electrically connecting the conductive particle and the electrode. And can be physically and physically connected. In addition, a brittle layer called an intermetallic compound may be formed between the first metal layer and the second metal layer containing a metal species different from the first metal layer when left in contact with each other at a high temperature. Although the fragile layer can be a factor in reducing the connection reliability, the first metal layer is left on the surface of the first metal layer where the second metal layer is not formed. A layer exists stably and connection reliability can be kept still better.

  The conductive particles may include a third metal layer containing palladium or a palladium alloy between the first metal layer and the second metal layer. In this case, the palladium content of the third metal layer is preferably 90% by mass or more. For example, when a layer containing nickel or a nickel alloy is employed as the first metal layer, by providing a third metal layer (a layer containing palladium or a palladium alloy) between the first metal layer and the second metal layer, It can fully suppress that the nickel contained in one metal layer reacts with the tin contained in the second metal layer to form a Sn—Ni-based compound between these layers. More specifically, when the conductive particles have the third metal layer, palladium contained in the third metal layer diffuses into the second metal layer, and is further partially taken into the Sn-Ni compound. It becomes a Sn-Ni-Pd-based compound. Thereby, it can suppress that the layer which consists of a Sn-Ni-type compound between the 1st metal layer and the 2nd metal layer is formed thick, and can maintain the reliability of electroconductive particle favorably. The Sn—Ni-based compound is a case where nickel and tin are close to each other (when the third metal layer is not present) and can be exposed to an environment of 100 ° C. The reliability will be reduced.

  When a layer containing nickel or a nickel alloy is employed as the first metal layer, the first metal layer may contain at least one of phosphorus and boron. Phosphorus and / or boron contained in the first metal layer suppresses diffusion of tin from the second metal layer into the first metal layer. Thereby, while being able to suppress that a 1st metal layer becomes thin, it can suppress that a Sn-Ni type compound arises between a 1st metal layer and a 2nd metal layer. These matters contribute to keeping the reliability of the conductive particles good.

  Examples of the material constituting the first electrode of the first circuit member include copper, nickel, palladium, gold, silver, and alloys thereof, and indium tin oxide.

  ADVANTAGE OF THE INVENTION According to this invention, even if the connection location of the circuit members which should be electrically connected mutually is minute, the connection structure which is excellent in both insulation reliability and conduction | electrical_connection reliability, and its manufacturing method are provided. Moreover, according to this invention, the manufacturing method of the electrode with a terminal useful for manufacturing the said connection structure, the electrically-conductive particle used for this, a kit, and a transfer type | mold are provided.

FIG. 1 is a cross-sectional view schematically showing an embodiment of conductive particles according to the present invention. FIG. 2 is a sectional view schematically showing another embodiment of the conductive particles according to the present invention. FIG. 3 is a cross-sectional view schematically showing a state where the conductive particles according to the present invention are fused to the electrode surface. FIG. 4 is an enlarged view showing a part of the connection structure according to the present invention, and schematically shows an example of a state in which the first electrode and the second electrode are electrically connected by the conductive particles. It is sectional drawing. FIG. 5 is a cross-sectional view schematically showing an embodiment of a connection structure according to the present invention. FIGS. 6A and 6B are cross-sectional views schematically showing an example of a process of forming the second metal layer by sputtering on a part of the surface of the conductive particle accommodated in the opening of the transfer mold. . FIG. 7A to FIG. 7C are cross-sectional views schematically showing an example of the process of forming the electrode with a terminal on the first circuit member. FIG. 8A is a plan view schematically showing one embodiment of a transfer mold according to the present invention, and FIG. 8B is a cross-sectional view taken along the line bb shown in FIG. FIG. 9 is a cross-sectional view schematically showing a state in which conductive particles before forming the second metal layer are captured in the transfer-type recess (opening). 10 (a) to 10 (d) show an example of a process of forming a connection structure including the first circuit member on which the electrode with terminal shown in FIG. 7 (c) is formed and the second circuit member. It is sectional drawing which shows this typically. 11 (a) and 11 (b) are other processes of forming a connection structure including the first circuit member on which the electrode with terminal shown in FIG. 7 (c) is formed and the second circuit member. FIG. FIG. 12 is a plan view schematically showing a circuit member in which a total of eight conductive particles are fused to each electrode. FIG. 13 is a plan view schematically showing a circuit member in which a total of four conductive particles are fused to each electrode.

  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.

<Conductive particles>
A conductive particle 10 </ b> A shown in FIG. 1 is a spherical particle including a base particle 1 and a metal layer 3 having a two-layer structure formed on the surface of the base particle 1. The conductive particles 10A are used by being fused to the electrode surface prior to circuit connection. Therefore, unlike the conductive particles blended in the conventional anisotropic conductive adhesives described in Patent Documents 1 to 3, the insulating particles are not attached to the particle surfaces. The term “spherical” as used herein includes not only a true sphere but also an ellipsoid, an arbitrary rotating body, and the like. For example, the aspect ratio may be 0.5 or more, and 0.8 or more. There may be.

  The particle size of the conductive particles 10A is, for example, 2.3 to 25 μm, and may be 3 to 20 μm or 3.5 to 10 μm. If the particle size of the conductive particles 10A is 2.3 μm or more, the conductive particles tend to absorb the impact sufficiently even if an impact is applied to the conductive particles. On the other hand, if the particle size is 25 μm or less, the conductive particles The variation in the particle size can be made sufficiently small, which makes it easy to achieve both conduction reliability and insulation reliability. The particle diameter of the conductive particles 10A can be measured by observation using a scanning electron microscope (hereinafter referred to as SEM). That is, the average particle diameter of the conductive particles can be obtained by measuring the particle diameter by observation using 300 SEMs for arbitrary 300 conductive particles and taking the average value thereof.

[Base material particles]
The base particle 1 is made of a spherical and non-conductive material. The particle diameter of the base particle 1 is, for example, 1.5 to 10 μm, and may be 2 to 10 μm. If the particle size is 1.5 μm or more, the base particles 1 tend to absorb the impact sufficiently even if an impact is applied to the conductive particles. On the other hand, if the particle size is 10 μm or less, the base particles 1 It tends to be possible to sufficiently reduce the variation in particle size of the particles. The particle diameter of the base particle 1 can be measured by observation using an SEM. The average particle diameter of the base particle 1 is obtained by measuring the particle diameter by observation using an SEM for 300 arbitrary base particles and taking the average value thereof.

  Although it does not specifically limit as a material of the base particle 1, Resin or a silica can be employ | adopted. Specific examples thereof include acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polyolefin resins such as polyethylene, polypropylene, polyisobutylene and polybutadiene; glass; silica and the like. When resin particles are employed as the substrate particles 1, for example, crosslinked acrylic particles, crosslinked polystyrene particles, and the like can be used. Assuming that reflow connection with solder is performed, the glass transition point (Tg) of the base particle 1 is preferably higher than the melting point of the solder. Taking Sn-3 mass% Ag-0.5 mass% Cu, which is widely used as an example, the melting point is 217 to 219 ° C., so that the base particle 1 has a Tg of, for example, 220 ° C. or higher. Any material may be used. By adopting such a material, even if the solder is melted for reflow connection, if the temperature is lower than the Tg of the base particle 1, deformation of the base particle 1 is sufficiently suppressed. The particles 1 exhibit excellent dimensional stability, and this tends to provide good connection reliability and insulation reliability.

[Metal layer]
As shown in FIG. 1, the metal layer 5 has a two-layer structure and covers the base particle 1. 3 A of metal layers have the 1st metal layer 3a containing nickel or a nickel alloy, and the 2nd metal layer 3b containing tin or a tin alloy in an order from the base particle 1 side.

(First metal layer)
The first metal layer 3 a is a layer containing nickel or a nickel alloy as the first metal, and covers the surface of the base particle 1. The nickel content of the first metal layer 3a is, for example, 85 to 98 mass%, and may be 87 to 96 mass% or 90 to 95 mass%. If nickel content is 85-98 mass%, after the below-mentioned 2nd metal layer 3b (layer containing tin or a tin alloy) joined to an electrode (refer FIG. 4), the 1st metal layer 3a will be stabilized. It remains, and this tends to maintain high connection reliability. The first metal layer 3a does not necessarily have to cover the entire surface of the substrate particle 1, and preferably covers 80% or more, more preferably 90% or more of the surface of the substrate particle 1. Good.

  The thickness of the first metal layer 3a is, for example, in the range of 0.05 to 5 μm, and may be in the range of 0.1 to 3 μm or 0.2 to 2 μm. If the thickness of the 1st metal layer 3a is 0.05 micrometer or more, after the below-mentioned 2nd metal layer 3b (layer containing tin or a tin alloy) joined to an electrode (refer FIG. 4), the 1st metal layer 3a Tends to remain stable, thereby maintaining high connection reliability. When the thickness of the first metal layer 3a is less than 0.05 μm, the nickel contained in the first metal layer 3a is tin contained in the second metal layer 3b after the second metal layer 3b is joined to the electrode. Alternatively, it diffuses into the tin alloy, thereby forming a discontinuous film, and as a result, the connection reliability tends to decrease.

  The first metal layer 3a may contain at least one of phosphorus and boron, and may particularly contain phosphorus. Thereby, after the 2nd metal layer 3b joined to an electrode, it can control that nickel contained in the 1st metal layer 3a diffuses into tin or a tin alloy contained in the 2nd metal layer 3b, As a result, it can fully suppress that the thickness of the 1st metal layer 3a reduces.

  The first metal layer 3a can be formed by electroless nickel plating. The formation of the first metal layer 3a by electroless nickel plating may be performed by a known method. For example, after the surface of the base particle 1 is treated with a palladium catalyst, electroless nickel plating may be performed. More preferably, phosphorus can be codeposited by using a phosphorus-containing compound such as sodium hypophosphite as a reducing agent for electroless nickel plating, and an alloy containing nickel and phosphorus (nickel-phosphorus alloy) ) Containing the first metal layer 3a. Alternatively, as a reducing agent, for example, boron can be co-deposited by using a boron-containing compound such as dimethylamine borane, sodium borohydride, potassium borohydride, etc., and an alloy containing nickel and boron (nickel-boron) The first metal layer 3a containing the alloy can be formed.

(Second metal layer)
The second metal layer 3b is a layer containing tin or a tin alloy as the second metal, partially covering the surface of the first metal layer 3a, and serving as a solder. As the tin alloy constituting the second metal layer 3b, for example, In-Sn, In-Sn-Ag, Sn-Bi, Sn-Bi-Ag, Sn-Ag-Cu, Sn-Cu, etc. can be adopted. Specific examples are given below.
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 may be selected as the metal (second metal) constituting the second metal layer 3b according to the temperature to be connected. For example, when connection is desired at a low temperature, the connection can be made at 150 ° C. or lower by employing an In—Sn alloy or a Sn—Bi alloy. On the other hand, when a material having a high melting point, such as Sn-Ag-Cu or Sn-Cu, is employed, the second metal layer 3b tends to be able to achieve high reliability even after being left at a high temperature in a state where it is bonded to the electrode. is there. The second metal layer 3b can contain a trace amount of metals such as Ni, Mn, Sb, Al, Zn, etc., if necessary, in addition to tin or tin alloy.

  The second metal layer 3b may not necessarily cover the entire surface of the first metal layer 3a, and preferably covers 20 to 60%, more preferably 30 to 50% of the surface of the first metal layer 3a. Just do it. The second metal layer 3b constitutes a part of the outermost layer of the conductive particles 10A and is joined to the electrode (see FIGS. 3 and 4).

  The thickness (thickest part) of the second metal layer 3b is, for example, in the range of 0.03 to 3 μm, and may be in the range of 0.05 to 2 μm or 0.1 to 1 μm. If the thickness of the second metal layer 3b is 0.03 μm or more, high reliability tends to be achieved in a state where the second metal layer 3b is bonded to the electrode. From the viewpoint of preventing the conductive particles 10A and the transfer mold from being connected by the second metal layer 3b formed by sputtering (see FIG. 6B), the upper limit value of the thickness of the second metal layer 3b is as described above. What is necessary is just to be about 3 micrometers.

  The second metal layer 3b may include Ag, Cu, Ni, Bi, Zn, Pd, Pb, Au, P, B, or two or more alloys selected from these, and among these, Ag or Cu from the following viewpoints: May be included. That is, since the second metal layer 3b contains Ag or Cu, the melting point of the second metal layer 3b can be lowered to about 220 ° C., and the connection strength with the electrode is improved, thereby improving the connection reliability. The effect is obtained.

  The Cu content of the second metal layer 3b 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.

Ag content rate of the 2nd metal layer 3b is 0.05-10 mass%, for example, and 0.1-5 mass% or 0.2-3 mass% may be sufficient. 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. By containing Ag in the second metal layer 3b, Ag ₃ Sn is formed in the second metal layer 3b, and this is dispersed in the solder, whereby the strength against the impact of the solder is improved.

  The second metal layer 3b can be formed by sputtering. The formation of the second metal layer 3b by sputtering is not particularly limited as long as it is possible to use a commercially available sputtering apparatus and is not particularly limited as long as it is a barrel type sputtering apparatus. A barrel sputtering device having a cylindrical shape, an oblique shape, or a polygonal shape tends to be able to suppress aggregation of particles.

(Third metal layer)
A conductive particle 10B shown in FIG. 2 is a spherical particle including a base particle 1 and a metal layer 3B formed on the surface of the base particle 1. As shown in FIG. 2, in the point that the metal layer 3B of the conductive particle 10B has a three-layer structure, that is, the third metal layer 3c is further provided between the first metal layer 3a and the second metal layer 3b. This is different from the conductive particles 10A including the metal layer 3A having a layer structure. Hereinafter, a configuration mainly related to this difference will be described.

  The particle diameter of the conductive particles 10B shown in FIG. 2 is, for example, 2.3 to 25 μm, and may be 3 to 20 μm or 3.5 to 10 μm, like the conductive particles 10A. If the particle size of the conductive particles 10B is 2.3 μm or more, even if an impact is applied to the conductive particles 10B, the conductive particles 10B tend to be able to sufficiently absorb the impact, while if the particle size is 25 μm or less, Variations in the particle size of the conductive particles 10B can be made sufficiently small, thereby making it easy to achieve both conduction reliability and insulation reliability. The particle diameter of the conductive particles 10B can be measured by observation using an SEM, similarly to the conductive particles 10A.

  The third metal layer 3c is a layer containing palladium or a palladium alloy. The third metal layer 3c can be formed, for example, through a palladium plating process, and is preferably an electroless plating type palladium layer. Electroless palladium plating may be performed using either a substitution type (a type that does not contain a reducing agent) or a reduction type (a type that contains a reducing agent). Examples of electroless palladium plating include APP (Ishihara Pharmaceutical Co., Ltd., trade name) for the reduction type, and MCA (trade name, manufactured by World Metal Co., Ltd.) for the replacement type. When the substitution type and the reduction type are compared, the reduction type is particularly preferable because voids tend to decrease. Compared to the substitution type that precipitates while dissolving the inner metal, the reduction type is preferable because the covering area is easily increased.

  The third metal layer 3c may have a multilayer structure. That is, the third metal layer 3c may have a first palladium plating film provided outside the first metal layer 3a and a second palladium plating film provided outside the film. The first palladium plating film is preferably a substituted or electroless palladium plating film having a purity of 99% by mass or more, and the second palladium plating film is preferably an electroless palladium plating film having a purity of 90% by mass or more and less than 99% by mass. The reason for this is as follows.

  That is, when a substitutional or reduced electroless palladium plating film having a purity of 99% by mass or more is formed alone as the third metal layer 3c, Pd is contained in the Sn—Cu—Ni compound or Sn—Ni compound. However, the reduced electroless palladium plating film having a purity of 90% by mass or more and less than 99% by mass has a higher effect of suppressing the growth of these compounds. . On the other hand, when the reduced electroless palladium plating film having a purity of 90% by mass or more and less than 99% by mass is formed alone as the third metal layer 3c, it is possible to increase the phosphorus content in the electroless palladium plating film. There is. On the other hand, it is difficult to deposit a coating with a uniform thickness on all of the substrate particles 1 on which the first metal layer 3a is formed, and a coating containing phosphorus (electroless palladium-phosphorus coating) is formed. Particles that are not formed or particles that are extremely thin are prone to occur. This phenomenon tends to appear more easily as the particle size of the conductive particles decreases. As a result, when a reduced electroless palladium plating film having a purity of 90% by mass or more and less than 99% by mass is formed alone, the palladium-phosphorus alloy plating film may not function as a protective layer for the first metal layer 3a. . On the other hand, the substitutional or reduced electroless palladium plating film having a purity of 99% by mass or more is more likely to deposit on the first metal layer 3a than the reduced electroless palladium plating film having a purity of 90% by mass or more and less than 99% by mass. It is easy to occur, and the first metal layer 3a is deposited on the entire surface of the substrate particles 1 having a sufficiently uniform thickness, and is deposited without depending on the particle size of the substrate particles 1. After forming a substituted or reduced electroless palladium plating film having a purity of 99% by mass or more, a reduced electroless palladium plating film having a purity of 90% by mass or more and less than 99% by mass is likely to be deposited on the surface. Precipitation occurs regardless of the particle size of the substrate particles 1. For this reason, the third metal layer 3c includes a first palladium plating film (a substituted or electroless palladium plating film having a purity of 99% by mass or more) provided outside the first metal layer 3a, and an outer side of this film. And a second palladium plating film (electroless palladium plating film having a purity of 90% by mass or more and less than 99% by mass).

  The third metal layer 3c may not remain as a layer by the diffusion of palladium in the second metal layer 3b after the second metal layer 3b is joined to the electrode. The palladium diffuses into the second metal layer 3b (a layer containing tin or a tin alloy), so that the Sn—Cu—Ni—Pd compound or the Sn—Ni—Pd compound is converted into the first metal layer 3a and the second metal. It can be formed between the layer 3b. The Pd content in these compounds is preferably 0.01 to 3% by mass, more preferably 0.02 to 1% by mass, and still more preferably 0.05 to 0.5% by mass. If the Pd content of the compound is 0.01% by mass or more, it is easy to obtain the effect of suppressing the growth of the Sn—Cu—Ni compound or Sn—Ni compound in a high temperature environment of about 100 ° C., If the Pd content is 3% by mass or less, the third metal layer 3c (palladium plating film) tends to diffuse and disappear in the solder, and the drop impact resistance reliability tends to be improved.

  The third metal layer 3c also functions as a layer that ensures wetting and spreading of the solder (second metal layer 3b). The thickness of the third metal layer 3c is, for example, 0.01 to 0.5 μm, and may be 0.03 to 0.4 μm or 0.05 to 0.3 μm. If the thickness of the third metal layer 3c is 0.01 μm or more, after the second metal layer 3b is joined to the electrode, the Sn—Cu—Ni—Pd compound or the Sn—Ni—Pd compound is used. It is easy to make the Pd content 0.01% by mass or more, and as a result, it is easy to obtain the effect of suppressing the growth of Sn—Cu—Ni compound or Sn—Ni compound in a high temperature environment of about 100 ° C. If it is 0.5 μm or less, the third metal layer 3c (palladium plating film) tends to diffuse and disappear in the solder, and there is a tendency to improve the drop impact resistance reliability.

<Electrode with terminal>
FIG. 3 is a perspective view schematically showing the terminal-equipped electrode 35 according to the present embodiment. That is, this figure schematically shows a state in which the conductive particles 10A are fused to the surface of the electrode 32 of the first circuit member 30, and the conductive particles 10A serve as bumps (connection protrusions) on the surface of the electrode 32. Fulfill. The first circuit member 30 includes a first circuit board 31 and a first electrode 32 disposed on the surface 31a. As shown in FIG. 3, the first metal layer 3a of the conductive particles 10A is fused to the first electrode 32 through a process of once melting and then solidifying. In the present specification, "fusion" is a state in which at least a part of the first metal layer 3a is melted by heat and then the conductive particles are bonded to the surface of the electrode through a process of solidifying. Means. Here, although the conductive particles 10A are employed, the conductive particles 10B may be employed instead.

  Specific examples of the first electrode 32 include copper, copper / nickel, copper / nickel / gold, copper / nickel / palladium, copper / nickel / palladium / gold, copper / nickel / gold, copper / palladium, copper / palladium. Examples include electrodes such as / gold, copper / tin, copper / silver, and indium tin oxide. The first electrode 32 can be formed by electroless plating, electrolytic plating, or sputtering.

<Connection structure>
FIG. 4 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 conductive particles 10A. The second circuit member 40 includes a second circuit board 41 and a second electrode 42 disposed on the surface 41a.

  As shown in FIG. 4, the connection structure 50 </ b> A includes the first circuit member 30, the second circuit member 40, and the conductive particles 10 </ b> A interposed between the first electrode 32 and the second electrode 42. And an insulating resin layer 55 provided between the first circuit member 30 and the second circuit member 40. In the present embodiment, the second metal layer 3b of the conductive particle 10A is fused to the first electrode 32, and the first metal layer 3a is in contact with the surface of the second electrode. 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. Examples of the other of the circuit members 30 and 40 include wiring such as a flexible tape substrate having metal wiring, a flexible printed wiring board, a glass substrate on which indium tin oxide (ITO) or zinc oxide (IZO) is deposited, and the like. A substrate is mentioned.

  A connection structure 50A shown in FIG. 5 includes a plurality of connection parts (three shown in FIG. 5) by the conductive particles 10A shown in FIG. Since the electrical connection between the electrodes 32 and 42 facing each other is ensured by the conductive particles 10A, it is not necessary to use an anisotropic conductive adhesive. In other words, the insulating resin layer 55 does not contain conductive particles. What is necessary is just to adopt. Therefore, according to the present embodiment and its modification, the insulation reliability at a narrow pitch (for example, a pitch of 10 μm level) can be greatly improved.

  Examples of the application target of the connection structure 50A include devices such as a liquid crystal display, a personal computer, a mobile phone, a smartphone, and a tablet.

<Method for manufacturing electrode with terminal>
A method for manufacturing the electrode with terminal 35 will be described with reference to FIGS. Here, a method of manufacturing the electrode with terminal 35 by fusing a plurality of conductive particles 10A to the surface of the electrode 32 included in the first circuit member 30 will be described.

(Preparation of transfer mold)
First, a transfer mold 60 is prepared which is used when the second metal layer 3b of the plurality of conductive particles 10A is formed by sputtering and is arranged and fused on the surface of the electrode 32. 8A is a plan view of the transfer mold 60, and FIG. 8B is a cross-sectional view taken along line BB shown in FIG. 8A. FIG. 9 is a cross-sectional view showing a state where conductive particles before forming the second metal layer 3b are accommodated in a plurality of recesses (openings) 62 of the transfer mold 60. FIG. The plurality of recesses 62 are respectively provided at positions corresponding to the position of the surface of the electrode 32 where the conductive particles 10A are to be arranged.

  The recess 62 of the transfer mold 60 is preferably formed in a tapered shape whose opening area increases from the bottom 62 a side (back side) of the recess 62 toward the surface 60 a side of the transfer mold 60. That is, as shown in FIG. 9, the width of the bottom 62a of the recess 62 (width a in FIG. 9) is preferably narrower than the width of the opening in the surface 60a of the recess 62 (width b in FIG. 9). And the size (taper angle and depth) of the recessed part 62 should just be set according to the size of the electrically-conductive particle before 2nd metal layer 3b formation. That is, when the conductive particles before forming the second metal layer 3b are accommodated in the recess 62, the height of the conductive particles protruding from the recess 62 (the distance from the surface 60a of the transfer mold 60 to the upper end of the conductive particles (in FIG. 9) The distance c)) is preferably 1 μm or more, more preferably 2 μm or more, from the viewpoint of reliably bonding the conductive particles 10A to the surface of the electrode 32.

  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. Of these, from the viewpoint of holding the conductive particles in a state in which the conductive particles 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.

  By using the transfer mold 60, even if there is a certain width in the particle size distribution of the conductive particles before forming the second metal layer 3b, a plurality of conductive particles having a narrower particle size distribution width than this is easily selected. The second metal layer 3b can be formed on these surfaces by sputtering, and the conductive particles 10A can be disposed on the surfaces of the electrodes 32. That is, even if the conductive particles smaller than the size of the concave portion 62 of the transfer mold 60 are once accommodated in the concave portion 62, for example, they fall if the surface on which the concave portion 62 is formed faces downward, whereas the conductive particles are smaller than the size of the concave portion 62. Large conductive particles are not accommodated in the recess 62. Conductive particles that fit the size of the recess 62 fit into the recess 62. While maintaining this state, after forming the second metal layer 3b by sputtering, the surface of the transfer mold 60 on which the concave portion 62 is formed is brought into contact with the electrode surface, whereby a plurality of conductive particles 10A are formed on the surface of the electrode 32. It can arrange | position according to the formation pattern of the recessed part 62 (refer Fig.7 (a) and FIG.7 (b)). Here, the concave portion 62 (bottomed opening) is exemplified as the opening in which the conductive particles are disposed, but the opening may be configured by a hole penetrating from the front surface to the back surface of the transfer mold.

(Formation of second metal layer)
FIG. 6A schematically shows a state in which the transfer mold 60 faces the surface of the sputtering electrode 70 in a state where the conductive particles before forming the second metal layer 3 b are accommodated in the respective recesses 62 of the transfer mold 60. FIG. The sputtering electrode 70 is made of a layer containing tin or a tin alloy. FIG. 6B is a cross-sectional view schematically showing a state in which the second metal layer 3 b is formed by sputtering on a part of the surface of the conductive particles accommodated in the recess 62 of the transfer mold 60. Note that a layer 80 containing tin or a tin alloy is also formed on the surface of the transfer mold 60 by sputtering.

(Disposition and fusion of conductive particles)
FIG. 7A is a cross-sectional view schematically showing a state in which the transfer mold 60 in which the conductive particles 10 </ b> A are accommodated in the respective recesses 62 faces the surface of the first circuit member 30. FIG. 7B is a cross-sectional view schematically showing a state in which the conductive particles 10 </ b> A accommodated in the recesses 62 of the transfer mold 60 are in contact with the surface of the first electrode 32. The transfer die 60 remains in a state in which the conductive particles 10A are accommodated in the recesses 62 after the second metal layer 3b is formed by sputtering. By performing the formation of the second metal layer 3b by sputtering and the arrangement of the conductive particles 10A on the electrodes continuously and with one transfer mold 60, the work efficiency can be improved. In addition, as shown in FIG. 7B, the thickest portion of the second metal layer 3b can be brought into contact with the surface of the first electrode 32, and the connection reliability can be improved.

  FIG. 7C is a cross-sectional view schematically showing a state where the conductive particles 10 </ b> A are fused to the surface of the first electrode 32. In the state shown in FIG. 7B, the first metal layer 3a is melted by heating at least the conductive particles 10A to a temperature (for example, 130 to 260 ° C.) higher than the melting point of the second metal layer 3b of the conductive particles 10A. Then, the conductive particles 10A can be fused to a predetermined position of the first electrode 32 by cooling. Thereby, the electrode 35 with a terminal is obtained (refer FIG.3 and FIG.7 (c)).

<Method for manufacturing connection structure>
A method of manufacturing the connection structure 50 will be described with reference to FIGS. These drawings schematically illustrate an example of a process of forming a connection structure including the first circuit member 30 on which the terminal-attached electrode 35 shown in FIG. 7C is formed and the second circuit member 40. It is sectional drawing shown. In the present embodiment, an insulating resin film 55p having a predetermined thickness made of an insulating resin material is prepared in advance (FIG. 11A) and laminated on the surface of the first circuit member 30. The surface of the first circuit member 30 (including the terminal-attached electrode 35) is covered (see FIG. 11B). The second circuit member 40 is arranged on the laminated insulating resin film 55p so that the surface on which the second electrode 42 is formed faces (see FIG. 11C). Thereafter, the electrode 35 is brought into contact with the second electrode 42 by applying pressure in the thickness direction of the laminate of these members (directions of arrows A and B shown in FIG. 11D). When the insulating resin film is made of, for example, a thermosetting resin, the thermosetting resin can be cured by heating the whole when pressurizing in the directions of 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. If the heating temperature at this time is set higher than the melting point of the first metal layer 3a of the conductive particles 10A, the conductive particles 10A can be fused to the second electrode 42 as shown in FIG. . Here, the case where the insulating resin film 55p is arranged on the surface of the first circuit member 30 is illustrated, but instead of this, a paste-like insulating resin composition is applied to the surface of the first circuit member 30. Also good.

  A modification of the method for manufacturing the connection structure 50 will be described with reference to FIGS. In this modification, an insulating resin film 55p is disposed between the first circuit member 30 on which the electrode with terminal 35 is formed and the second circuit member 40 (see FIG. 11A), and then The electrode 35 is brought into contact with the second electrode 42 by applying pressure in the thickness direction of the laminate of these members (directions of arrows A and B shown in FIG. 11B). When the insulating resin film is made of, for example, a thermosetting resin, the thermosetting resin can be cured by heating the whole when pressurizing in the directions of 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.

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 conductive particles]
(Process a) Pretreatment process 4 g of cross-linked polystyrene particles having an average particle size of 4.0 μm (product name “Soliostar” manufactured by Nippon Shokubai Co., Ltd.) and Atotech Neo Gant 834 (product manufactured by Atotech Japan Co., Ltd., product) Was added to 100 mL of a palladium-catalyzed solution containing 8% by mass and stirred at 30 ° C. for 30 minutes. Next, after filtering with a φ3 μm membrane filter (manufactured by Merck & Co., Inc.), resin particles were obtained by washing with water. Thereafter, resin particles were added to a 0.5 mass% dimethylamine borane liquid adjusted to pH 6.0 to obtain resin particles whose surface was activated. And after immersing the resin particle in which the surface was activated in 20 mL distilled water, the resin particle dispersion liquid was obtained by carrying out ultrasonic dispersion | distribution.

(Step b) Formation of first metal layer After the resin particle dispersion obtained through step a was diluted with 1000 mL of water heated to 80 ° C., 1 mL of 1 g / L bismuth nitrate aqueous solution was added as a plating stabilizer. . Next, electroless nickel for forming a first metal layer having the following composition (an aqueous solution containing the following components. 1 g / L bismuth nitrate aqueous solution was added in an amount of 1 mL per liter of plating solution; the same applies hereinafter) to a dispersion containing 2 g of resin particles. 500 mL of plating solution was added dropwise at a dropping rate of 5 mL / min. After 10 minutes had elapsed after the completion of the dropping, the dispersion with the plating solution added was filtered. The filtrate was washed with water and then dried with a vacuum dryer at 80 ° C. Thus, the 1st layer which consists of a nickel-phosphorus alloy film (nickel concentration 93 mass%, remainder phosphorus) of the film thickness of 0.5 micrometer shown in Table 1 was formed. The particle A obtained by forming the first layer was 8 g, and the outer diameter was 5 μm.
(Electroless nickel plating solution for first layer formation)
Nickel sulfate: 400 g / L
Sodium hypophosphite: 150 g / L
Acetic acid: 120 g / L
Bismuth nitrate aqueous solution (1 g / L): 1 mL / L

(Step c) Formation of the second metal layer As a transfer mold, an opening diameter of 6 μm square, a bottom diameter of 3 μm square, a depth of 5 μm (the bottom diameter of 3 μm square is located at the center of the opening diameter of 6 μm square when the opening is viewed from the top. A polyimide film (thickness: 100 μm) having a concave portion is prepared. The particles A obtained through the step b were placed in the opening of the transfer mold. A solder layer (second metal layer) having a composition of Sn-3.0Ag-0.5Cu was formed to 0.2 μm by sputtering on the transfer mold and the particles A arranged in the recesses. This thickness (0.2 μm) is the thickness of the thickest part of the solder layer. The area ratio (coverage) of the portion covered with the solder layer on the surface of the conductive particles was about 50%.

Specifically, sputtering was performed as follows. That is, a transfer mold in which conductive particles are arranged in the recesses was placed in a sputtering apparatus, the pressure inside the apparatus was reduced to 1 × 10 ⁻⁴ Pa or less, and then argon was flowed at a constant flow rate so that the inside of the apparatus became 1 Pa. Thereafter, a voltage was applied to the target to form a sputtering layer on the surface of the particle A and the surface of the transfer mold. Sputtering was performed until the sputtering layer having a composition of Sn-3.0Ag-0.5Cu became 0.2 μm, and then the inside of the apparatus was returned to atmospheric pressure. Then, the conductive particles having a solder layer (second metal layer) having a composition of Sn-3.0Ag-0.5Cu were taken out from the apparatus together with the transfer mold.

[Production of electrodes with terminals]
(Process d)
After being taken out from the sputtering apparatus with a chip (1.7 × 1.7 mm, thickness: 0.5 mm) with copper bumps (area 15 μm × 30 μm, space 10 μm, height: 10 μm, number of bumps 362) The transfer mold in which the conductive particles are arranged in the recesses face each other, and the copper bumps and the conductive particles are brought into contact with each other. Using a vacuum reflow soldering apparatus [vacuum reflow soldering apparatus VADU100 manufactured by PINK (Germany)], holding for 1 minute at a formic acid concentration of 2 mass%, a pressure of 2000 Pa, and 230 ° C. (1.7 × 1.7 mm, thickness: 0.5 mm) was obtained. More specifically, as shown in FIG. 12, an electrode-attached chip C1 with terminals in which eight conductive particles were arranged at a pitch of 8 μm on a copper bump was obtained. In the same manner, chips C2 and C3 (1.7 × 1.7 mm, thickness: 0.5 mm) having the following configuration were obtained. FIG. 13 is a plan view schematically showing a chip C2 (circuit member) in which four conductive particles are arranged at a pitch of 8 μm on a copper bump.
Chip C1: Area 15 μm × 30 μm, Space 10 μm, Height: 10 μm, Bump number 362, Eight conductive particles on copper bumps Chip C2: Area 15 μm × 15 μm, Space 10 μm, Height: 10 μm, Bump number 362 Four conductive particles on copper bumps, chip C3: area 15 μm × 30 μm, space 6 μm, height: 10 μm, number of bumps 362, number of conductive particles on copper bumps 8

[Production of connection structure]
(Process e)
Copolymer of 100 g of phenoxy resin (trade name “PKHC” manufactured by Union Carbide) and 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, molecular weight: 85 10) 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 Epoxy Co., Ltd., 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, dried by heating at 90 ° C. for 10 minutes, and an adhesive film having a thickness of 10 μm. (Insulating resin film) was produced on the separator.

Next, using the produced adhesive film, connection between the electrode-equipped chip with terminal (1.7 × 1.7 mm, thickness: 0.5 mm) and the glass substrate with IZO circuit (thickness: 0.7 mm) Was performed according to the following procedures i) to iii) to obtain a connection structure.
i) An adhesive film (2 × 19 mm) was attached to a glass substrate with an IZO circuit at 80 ° C. and 0.98 MPa (10 kgf / cm ² ).
ii) The separator was peeled off, and the bumps of the chip and the glass substrate with IZO circuit were aligned.
iii) The main connection was performed by heating and pressing from above the chip under the conditions of 190 ° C., 40 gf / bump, and 10 seconds. The conditions of the produced conductive particles and the like are summarized in Table 1.

<Evaluation of film thickness and components of conductive particles>
A cross section was cut out by an ultramicrotome method so as to pass through the vicinity of the center of the obtained conductive particles. Observation was carried out at an arbitrary magnification using a transmission electron microscope apparatus (hereinafter abbreviated as “TEM apparatus”, manufactured by JEOL Ltd., trade name “JEM-2100F”). From the obtained image, the thickness of each coating in the radial direction from the center of the conductive particles was measured. Each of the five conductive particles was measured at five locations, and the average value at a total of 25 locations was defined as the film thickness. Further, the content (purity) of the element in each coating was calculated from the EDX mapping data.

[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 electrode (bump) / glass electrode (IZO), after the initial value of the conduction resistance and the moisture absorption heat resistance test (left at 100, 300, 500, 1000, 2000 hours under conditions of temperature 85 ° C. and humidity 85%) Was measured for 20 samples, and the average value thereof was calculated. In addition, it evaluated using the above-mentioned chip C1 and chip C2. The conduction resistance was evaluated from the average value obtained according to the following criteria. The results are shown in Table 2. In addition, it can be said that conduction resistance is favorable when the following A or B standard is satisfied after the moisture absorption heat test 500 hours.
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 electrode (bump) / glass electrode (IZO), the initial value of the conduction resistance and the value after the high temperature standing test (100, 300, 500, 1000 hours standing at a temperature of 100 ° C.) are 20 samples. Were measured and the average value thereof was calculated. In addition, it evaluated using the above-mentioned chip C1. The conduction resistance was evaluated from the average value obtained according to the following criteria. The results are shown in Table 2. In addition, it can be said that conduction resistance is favorable when the following A or B standard is satisfied after 100 hours of high-temperature standing 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

(Insulation resistance test)
Regarding the insulation resistance between chip electrodes, the initial value of the insulation resistance and the value after migration test (temperature 60 ° C., humidity 90%, 20 V applied for 100, 300, 500, 1000 hours) were measured for 20 samples. And the ratio of the sample from which the insulation resistance value becomes 10 ⁹ Ω or more among all 20 samples was calculated. In addition, it evaluated using the above-mentioned chip C1 and chip C3. 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 500 hours of the moisture absorption heat test.
A: Ratio of insulation resistance value 109Ω or more is 100%
B: Ratio of insulation resistance value 109Ω or more is 90% or more and less than 100% C: Ratio of insulation resistance value 109Ω or more is 80% or more and less than 90% D: Ratio of insulation resistance value 109Ω or more is 50% or more and less than 80% E: Ratio of insulation resistance value 109Ω or more is less than 50%

<Example 2>
In (step c), a target of Sn—Bi (Sn 43 mass%, Bi 57 mass%) is used instead of a target having a composition of Sn-3.0Ag-0.5Cu, and heating in iii) of (step e) In the same manner as in Example 1 except that the condition was changed from 190 ° C. to 150 ° C., the production of conductive particles and electrodes with terminals, the production of connection structures, and the evaluation of the conductive particles and connection structures were performed. . The conditions of the produced conductive particles and the like are summarized in Table 1. The evaluation results are shown in Table 2.

<Example 3>
After performing (Step a) and (Step b) of Example 1, 8 g of particles forming the first metal layer (nickel) were diluted with 200 mL of water heated at 50 ° C., and 1 g / 0.2 mL of L aqueous bismuth nitrate solution was added, and 100 mL of an electroless palladium plating solution for forming a third metal layer having the following composition was added dropwise at a dropping rate of 1 mL / min. After 10 minutes had elapsed after the completion of the dropping, the dispersion with the plating solution added was filtered. The filtrate was washed with water and then dried with a vacuum dryer at 80 ° C. In this way, a third metal layer made of a palladium plating film (palladium purity 100%) having a thickness of 0.1 μm was formed. In addition, the particle | grains obtained by forming 0.5 micrometer of 1st metal layers (nickel) and 0.1 micrometer of 3rd metal layers (palladium) in order from the inside on the outer side of an acrylic particle are 9g, and an outer diameter is 5. It was 2 μm. Subsequently, the same operation as in (Step c) of Example 1 was performed, and the surface of the conductive particles arranged in the concave portion of the transfer mold had a composition of Sn-3.0Ag-0.5Cu having a thickness of 0.2 μm. A solder layer (second metal layer) was formed. Thereafter, the same operations as in (step d) onward in Example 1 were performed, and the production of the electrode with terminals, the production of the connection structure, and the evaluation of the conductive particles and the connection structure were performed. The conditions of the produced conductive particles and the like are summarized in Table 1. The evaluation results are shown in Table 2.
(Electroless palladium plating solution)
Palladium chloride: 7g / L
EDTA · 2 sodium: 100 g / L
Citric acid, disodium: 100 g / L
Sodium formate: 20 g / L
pH: 6

<Example 4>
After performing (Step a) and (Step b) of Example 1, a third metal layer formed of a palladium plating film (palladium purity 100%) with a thickness of 0.1 μm is formed in the same manner as Example 3. And the particle | grains (outer diameter: 5.2 micrometers) which consisted of 0.5 micrometer of 1st metal layers (nickel) and 0.1 micrometer of 3rd metal layers (palladium) in order from the inner side were produced on the outer side of the acrylic particles. Thereafter, as in Example 2, a 0.2 μm thick solder layer (second metal layer, type: Sn—Bi (Sn 43 mass%, Bi 57 mass%)) was applied to the surface of the conductive particles using a transfer mold. Formed. About (process d) and subsequent, it carried out similarly to Example 2, preparation of the electroconductive particle and the electrode with a terminal, preparation of a connection structure, and evaluation of the electroconductive particle and the connection structure were performed. The conditions of the produced conductive particles and the like are summarized in Table 1. The evaluation results are shown in Table 2.

<Comparative Example 1>
[Preparation of conductive particles]
In Example 1 (step a), instead of 4 g of crosslinked polystyrene particles having an average particle diameter of 4.0 μm (trade name “Soliostar” manufactured by Nippon Shokubai Co., Ltd.), crosslinked polystyrene particles having an average particle diameter of 3.0 μm ( After performing the same operation using 2 g of Nippon Shokubai Co., Ltd., trade name “Soriostar”, Example 1 (Step b) was continued, the amount of electroless nickel plating was 100 mL, and Table 3 The 1st metal layer which consists of a nickel-phosphorus alloy film (nickel concentration 93 mass%, remainder phosphorus) of the film thickness of 0.1 micrometer shown in FIG. The particle A obtained by forming the first metal layer was 2.8 g, and the outer diameter was 3.2 μm. Subsequently, a third metal layer made of a palladium plating film (palladium purity 100%) was formed on the first metal layer by the same electroless palladium plating solution and method as in Example 3. By changing the electroless palladium plating solution for forming the third metal layer from 100 mL to 20 mL and forming a palladium plating film of 0.02 μm, the first metal layer (nickel) 0.1 μm in order from the inside to the outside of the acrylic particles. Then, 3 g of conductive particles having an outer diameter of 3.24 μm and a third metal layer (palladium) of 0.02 μm were formed.

[Production of first insulating particles]
Monomers were added to 400 g of pure water in a 500 ml flask according to the blending molar ratio shown below. It mix | blended so that the total amount of all the monomers might be 10 mass% with respect to pure water. After nitrogen substitution, heating was performed for 6 hours with stirring at 70 ° C. The stirring speed was 300 min-1 (300 rpm). KBM-503 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) is 3-methacryloxypropyltrimethoxysilane. The average particle diameter of the first insulating particles obtained by synthesis was 315 nm, and Tg was 116 ° C.
(Mixing molar ratio of first insulating particles)
Styrene: 600
Potassium peroxodisulfate: 6
Sodium methacrylate: 5.4
Sodium styrene sulfonate: 0.32
Divinylbenzene: 16.8
KBM-503: 4.2

[Production of second insulating particles]
Monomers were added to 400 g of pure water in a 500 ml flask according to the blending molar ratio shown below. It mix | blended so that the total amount of all the monomers might be 10 mass% with respect to pure water. After nitrogen substitution, heating was performed for 6 hours with stirring at 70 ° C. The stirring speed was 300 min-1 (300 rpm). The second insulating particles obtained by synthesis had an average particle size of 100 nm and Tg of 116 ° C.
(Mixing molar ratio of second insulating particles)
Styrene: 600
Potassium peroxodisulfate: 6
Methyl acrylate: 270
Sodium methacrylate: 5.4
Sodium styrenesulfonate: 2.0
Divinylbenzene: 16.8
KBM-503: 4.2

  The average particle diameter of the first insulating particles and the second insulating particles was measured by image analysis of HITACHI S-4800 (Hitachi High-Technologies Corporation, trade name). The Tg of the first insulating particles and the second insulating particles was determined by using DSC (DSC-7 type manufactured by PerkinElmer Japan Co., Ltd.), sample amount 10 mg, temperature rising rate 5 ° C./min, measurement atmosphere: air condition Measured with

(Preparation of silicone oligomer 1)
A solution containing 118 g of 3-glycidoxypropyltrimethoxysilane and 5.9 g of methanol was added to a glass flask equipped with a stirrer, a condenser and a thermometer. Further, 5 g of activated clay and 4.8 g of distilled water were added and stirred at 75 ° C. for a certain time, and then a silicone oligomer having a weight average molecular weight of 1300 was obtained. The obtained silicone oligomer 1 has a methoxy group or a silanol group as a terminal functional group that reacts with a hydroxyl group. Methanol was added to the obtained silicone oligomer solution to prepare a treatment liquid having a solid content of 20% by weight.

In addition, the weight average molecular weight of the silicone oligomer was measured by a gel permeation chromatography method (GPC) method, and was calculated by conversion using a standard polystyrene calibration curve. The GPC conditions are shown below.
GPC conditions Pump: Hitachi L-6000 type (manufactured by Hitachi, Ltd., trade name)
Column: Gelpack GL-R420, Gelpack GL-R430, Gelpack GL-R440 (above, manufactured by Hitachi Chemical Co., Ltd., trade name)
Eluent: Tetrahydrofuran (THF)
Measurement temperature: 40 ° C
Flow rate: 2.05 mL / min Detector: Hitachi L-3300 type RI (“trade name, manufactured by Hitachi, Ltd.)

[Preparation of insulating coated conductive particles]
A reaction solution was prepared by dissolving 8 mmol of mercaptoacetic acid in 200 ml of methanol. Next, 3 g of conductive particles having an outer diameter of 3.24 μm, in which a first layer (nickel) 0.1 μm and a third layer (palladium) 0.02 μm were formed in order from the inside on the outside of the acrylic particles, were added to the reaction solution In addition, the mixture was stirred with a three-one motor and a stirring blade having a diameter of 45 mm at room temperature for 2 hours. After washing with methanol, the resultant was filtered using a membrane filter (manufactured by Merck Millipore) having a pore size of 3 μm to obtain conductive particles having a carboxyl group on the surface.

  Next, a 30% polyethyleneimine aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd.) having a weight average molecular weight of 70,000 was diluted with ultrapure water to obtain a 0.3 wt% polyethyleneimine aqueous solution. The conductive particles having a carboxyl group on the surface were added to a 0.3% by weight polyethyleneimine aqueous solution and stirred at room temperature for 15 minutes. Thereafter, the conductive particles were filtered using a membrane filter (manufactured by Merck Millipore) having a pore size of 3 μm, and the filtered conductive particles were put in 200 g of ultrapure water and stirred at room temperature for 5 minutes. Furthermore, the conductive particles were filtered using a membrane filter (manufactured by Merck Millipore) having a pore size of 3 μm, and washed twice with 200 g of ultrapure water on the membrane filter. By performing these operations, unimsorbed polyethyleneimine was removed, and conductive particles whose surface was coated with an amino group-containing polymer were obtained.

  Next, the 1st insulating particle was processed with the silicone oligomer 1, and the methanol dispersion medium of the 1st insulating particle which has a glycidyl group containing oligomer on the surface was prepared. On the other hand, the second insulating particles were similarly treated with the silicone oligomer 1 to prepare a methanol dispersion medium of second insulating particles having a glycidyl group-containing oligomer on the surface.

  The conductive particles whose surfaces were coated with an amino group-containing polymer were immersed in isopropyl alcohol, and a methanol dispersion medium of first insulating particles was dropped. The coverage of the 1st insulating particle was adjusted with the dripping amount of the methanol dispersion medium of the 1st insulating particle. Subsequently, the insulation coating electroconductive particle 1 was produced by dripping the methanol dispersion medium of the 2nd insulating particle. The coverage of the second insulating particles was adjusted by the amount of the second insulating particles dropped. The coverage with the first insulating particles was 30%, the coverage with the second insulating particles was 25%, and the coverage with the insulating particles was 55% in total.

  The obtained insulating coated conductive particles 1 were treated with a condensing agent and octadecylamine and washed to make the surface hydrophobic. Thereafter, the insulating coated conductive particles 1 were produced by heating and drying at 80 ° C. for 1 hour.

[Production of anisotropic conductive adhesive film]
300 g of a solvent in which ethyl acetate and toluene are mixed at a weight ratio of 1: 1, 100 g of phenoxy resin (trade name: PKHC, manufactured by Union Carbide), acrylic rubber (40 parts by mass of butyl acrylate, 30 parts by mass of ethyl acrylate, acrylonitrile 30) 75 parts by weight of a copolymer of 3 parts by weight of glycidyl methacrylate and 75 g of a weight average molecular weight was obtained to obtain a solution. 300 g of liquid epoxy (Eboxy equivalent 185, manufactured by Asahi Kasei Epoxy Co., Ltd., trade name: NovaCure HX-3941) containing a microcapsule type latent curing agent in this solution, and liquid epoxy resin (made by Japan Epoxy Resin Co., Ltd., trade name) : YL980) 400 g was added and stirred. A silica slurry (manufactured by Nippon Aerosil Co., Ltd., trade name: R202) in which silica having an average particle size of 14 nm was solvent-dispersed was added to the obtained mixed solution to prepare an adhesive solution 1. The silica slurry was added so that the content of the silica solid content was 5% by weight with respect to the total solid content of the mixed solution.

  In a beaker, 10 g of a dispersion medium in which ethyl acetate and toluene were mixed at a weight ratio of 1: 1 and the insulating coated conductive particles 1 were placed and ultrasonically dispersed. The ultrasonic dispersion was performed by immersing the beaker in an ultrasonic bath (Fujimoto Kagaku Co., Ltd., trade name: US107) having a frequency of 38 kHz, energy of 400 W, and volume of 20 L, and stirring for 1 minute.

The obtained dispersion liquid of insulating coated conductive particles 1 was dispersed in the adhesive solution 1. The obtained dispersion was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater and dried at 90 ° C. for 10 minutes to prepare an adhesive film A having a thickness of 10 μm. This adhesive film has 70,000 pieces / mm ² of insulating coated conductive particles per unit area. Further, the adhesive solution 1 was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater and dried at 90 ° C. for 10 minutes to prepare an adhesive film B having a thickness of 3 μm. Further, the adhesive solution 1 was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater, and dried at 90 ° C. for 10 minutes to prepare an adhesive film C having a thickness of 10 μm. Next, each adhesive film was laminated in the order of the adhesive film B, the adhesive film A, and the adhesive film C to prepare an anisotropic conductive adhesive film D consisting of three layers.

[Preparation of connection sample]
Instead of the copper bumps in (Step d) of Example 1, electroless nickel plating (film thickness: 0.5 μm), electroless palladium plating (film thickness: 0.1 μm), displacement gold plating (film thickness) : 0.05 μm) in sequence (the area, space, height, and number of bumps of the bumps after electroless nickel plating / palladium plating / displacement gold plating are the same as the copper bumps of Example 1), copper / nickel / Palladium / gold bump (area 15 μm × 30 μm, space 10 μm, height: 10 μm, number of bumps 362) [electroless nickel plating (film thickness: 0.5 μm), electroless palladium plating (film thickness: 0.1 μm), replacement Example 1 (Using an anisotropic conductive adhesive film D produced using a chip (1.7 × 1.7 mm, thickness: 0.5 mm) with gold plating (film thickness: 0.05 μm)] Same as step e) IZO circuitized glass substrate (thickness: 0.7 mm) a connection with, was carried out as mentioned below.

The anisotropic conductive adhesive film D is attached to a glass substrate with an IZO circuit under conditions of a temperature of 80 ° C. and a pressure of 0.98 MPa (10 kgf / cm ² ), and then the separator is peeled off to prepare for the chip. A glass substrate provided with copper / nickel / palladium / gold bumps and electrodes was aligned. Next, heating and pressurization were performed for 10 seconds from above the chip under the conditions of a temperature of 190 ° C. and a pressure of 39 N / bump (40 gf / bump) to perform the main connection. The anisotropic conductive adhesive film D was disposed such that the adhesive film B was on the glass substrate side and the adhesive film C was on the metal bump side.

  The film thickness and component evaluation of the conductive particles, the conduction resistance test, and the insulation resistance test were performed in the same manner as in Example 1. Table 3 shows the conditions of the produced conductive particles and the like. The evaluation results are shown in Table 4.

<Comparative example 2>
[Preparation of conductive particles]
In Example 1 (step a), instead of 4 g of crosslinked polystyrene particles having an average particle size of 4.0 μm (trade name “Soliostar” manufactured by Nippon Shokubai Co., Ltd.), crosslinked polystyrene particles having an average particle size of 3.0 μm (stocks) The same operation was carried out using 2 g of a product manufactured by Nippon Shokubai Co., Ltd. (trade name “Soriostar”), and then (step b) of Example 1 was continuously performed to obtain a nickel-phosphorus alloy film (nickel of 0.5 μm thickness). A first layer having a concentration of 93 mass% and the balance phosphorus) was formed. Particles obtained by forming the first layer were 6 g, and the outer diameter was 4 μm. In the same manner as in Example 3, a third metal layer made of a palladium plating film (palladium purity 100%) having a thickness of 0.1 μm was formed. In addition, the particle | grains obtained by forming 0.5 micrometer of 1st metal layers (nickel) and 0.1 micrometer of 3rd metal layers (palladium) in order from the inner side on the outside of a crosslinked polystyrene particle are 7g, and an outer diameter is 4. .2 μm. An average of 0.5 μm of a solder layer (second metal layer) having a composition of Sn—Bi (Sn 43 mass%, Bi 57 mass%) was formed on 7 g of the particles on which the third metal layer (palladium) had been formed, by barrel sputtering. In the barrel sputtering, particles in which the third metal layer (palladium) is formed are placed in a cylindrical barrel having a Sn—Bi composition target inside the rotation drive unit, and the inside of the barrel is 1 × 10 ^−. After reducing the pressure to ⁴ Pa or less, argon was flowed at a constant flow rate so that the inside of the barrel became 1 Pa. Thereafter, the barrel was rotated and inverted to roll and agitate the particles. Furthermore, vibration was directly applied to the particles to suppress particle aggregation. Thereafter, a voltage was applied to the target to form a sputtering layer on the surface of the particles. Sputtering was performed until the sputtering layer having the composition of Sn—Bi (Sn 43 mass%, Bi 57 mass%) became 0.5 μm, then the inside of the barrel was returned to atmospheric pressure, and the conductive particles were taken out. The electroconductive particle 2 obtained by forming a 2nd metal layer was 11g, and the outer diameter was 5.2 micrometers. Particles were taken out and passed through a sieve having a diameter of 7 cm with a mesh opening diameter of 8 μm square to remove aggregates.

[Production of anisotropic conductive adhesive film]
In a beaker, 10 g of a dispersion medium in which ethyl acetate and toluene were mixed at a mass ratio of 1: 1 and the conductive particles 2 were placed and ultrasonically dispersed. The ultrasonic dispersion was performed by immersing the beaker in an ultrasonic bath (Fujimoto Kagaku Co., Ltd., trade name: US107) having a frequency of 38 kHz, energy of 400 W, and volume of 20 L, and stirring for 1 minute.

The obtained dispersion liquid of conductive particles 2 was dispersed in the adhesive solution 1 of Comparative Example 1. The obtained dispersion was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater and dried at 90 ° C. for 10 minutes to produce an adhesive film F having a thickness of 10 μm. This adhesive film has 30,000 particles / mm ² of conductive particles 2 per unit area. Further, the adhesive solution 1 was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater, and dried at 90 ° C. for 10 minutes to prepare an adhesive film G having a thickness of 3 μm. Further, the adhesive solution 1 was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater and dried at 90 ° C. for 10 minutes to prepare an adhesive film H having a thickness of 10 μm. Next, each adhesive film was laminated in order of the adhesive film G, the adhesive film F, and the adhesive film H, and the anisotropic conductive adhesive film I which consists of three layers was produced.

[Preparation of connection sample]
Using the produced anisotropic conductive adhesive film I, copper / nickel / palladium / gold bumps (area 15 μm × 30 μm, space 10 μm, height: 10 μm, number of bumps 362) similar to Comparative Example 1 [electroless Nickel plating (film thickness: 0.5 μm), electroless palladium plating (film thickness: 0.1 μm), displacement gold plating (film thickness: 0.05 μm)] chip (1.7 × 1.7 mm, thickness: 0.5 mm) and the same glass substrate with IZO circuit (thickness: 0.7 mm) as in Example 1 (step e) were connected as shown below.

The anisotropic conductive adhesive film I is attached to a glass substrate with an IZO circuit at a temperature of 80 ° C. and a pressure of 0.98 MPa (10 kgf / cm ² ), and then the separator is peeled off to prepare for the chip. A glass substrate provided with copper / nickel / palladium / gold bumps and electrodes was aligned. Next, heating and pressurization were performed for 10 seconds from above the chip under the conditions of a temperature of 190 ° C. and a pressure of 39 N / bump (40 gf / bump) to perform the main connection. The anisotropic conductive adhesive film I was disposed such that the adhesive film G was on the glass substrate side and the adhesive film H was on the metal bump side. The film thickness and component evaluation of the conductive particles, the conduction resistance test, and the insulation resistance test were performed in the same manner as in Example 1. Table 3 shows the conditions of the produced conductive particles and the like. The evaluation results are shown in Table 4.

DESCRIPTION OF SYMBOLS 1 ... Base particle, 3A, 3B ... Metal layer, 3a ... First metal layer, 3b ... Second metal layer, 3c ... Third metal layer, 10A, 10B ... Conductive particle, 30 ... First circuit member, 32 ... 1st electrode, 35 ... Electrode with terminal, 40 ... 2nd circuit member, 42 ... 2nd electrode, 50A ... Connection structure, 55 ... Insulating resin layer, 60 ... Transfer mold, 60a ... Surface, 62 ... Recess (opening), 62a ... bottom, 70 ... sputtering electrode, 80 ... layer containing tin or tin alloy

Claims (46)

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;
Providing a plurality of conductive particles having a surface comprising a first metal;
Containing the conductive particles in the openings of a transfer mold having a plurality of openings;
Forming a second metal layer made of a second metal containing tin or a tin alloy by sputtering on at least a part of the surface of the conductive particles accommodated in the opening;
Disposing the plurality of conductive particles on which the second metal layer is formed on a surface of the first electrode;
Fusing the conductive particles to the first electrode by heating the plurality of conductive particles disposed on the surface of the first electrode to a temperature higher than the melting point of the second metal;
One surface of the first circuit member that has the first electrode fused with the conductive particles, and one surface of the second circuit member that has the second circuit Forming an insulating resin layer between the surfaces;
The first electrode and the second electrode are heated by heating a laminate including the first circuit member, the insulating resin layer, and the second circuit member while being pressed in the thickness direction of the laminate. Are electrically connected via the conductive particles and bonded to the first circuit member and the second circuit member;
A method for manufacturing a connection structure including: The conductive particles have at least base particles and a first metal layer made of the first metal covering the surface of the base particles,
The method for manufacturing a connection structure according to claim 1, wherein the melting point of the first metal is higher than the melting point of the second metal.   The method for manufacturing a connection structure according to claim 2, wherein the conductive particles include a third metal layer containing palladium or a palladium alloy between the first metal layer and the second metal layer.   The manufacturing method of the connection structure of Claim 3 whose palladium content rate of a said 3rd metal layer is 90 mass% or more.   The manufacturing method of the connection structure as described in any one of Claims 2-4 whose particle size of the said base particle is 2-10 micrometers.   The method for manufacturing a connection structure according to any one of claims 2 to 5, wherein the base particle is made of a resin.   The method for manufacturing a connection structure according to any one of claims 1 to 6, wherein the first metal includes nickel or a nickel alloy.   The method for manufacturing a connection structure according to any one of claims 1 to 7, wherein the first metal includes at least one of phosphorus and boron.   The manufacturing method of the connection structure as described in any one of Claims 1-8 whose nickel content rate of said 1st metal is 85-98 mass%.   The manufacturing method of the connection structure as described in any one of Claims 1-9 whose tin content rate of said 2nd metal is 30-100 mass%.   The method for manufacturing a connection structure according to any one of claims 1 to 10, wherein the first electrode is made of copper, nickel, palladium, gold, silver, an alloy thereof, and indium tin oxide. The positions of the plurality of openings of the transfer mold correspond to the positions where the plurality of conductive particles in the electrode are disposed,
By superposing the first circuit member and the transfer mold, the conductive particles respectively accommodated in the openings of the transfer mold are arranged on the surface of the first electrode,
The conductive particles are fused to the first electrode by heating the plurality of conductive particles to a temperature higher than the melting point of the second metal in a state where the first circuit member and the transfer mold are overlapped. The manufacturing method of the connection structure as described in any one of Claims 1-11 made to wear.   The connection structure according to any one of claims 1 to 12, wherein the opening is formed in a tapered shape in which an opening area increases from a back side of the opening toward a surface side of the transfer mold. Production method.   The method for manufacturing a connection structure according to any one of claims 1 to 13, wherein the transfer mold is made of a flexible resin material. Providing a circuit member having a substrate and electrodes provided on the substrate;
Providing a plurality of conductive particles having a surface comprising a first metal;
Containing the conductive particles in the openings of a transfer mold having a plurality of openings;
Forming a second metal layer made of a second metal containing tin or a tin alloy by sputtering on a part of the surface of the conductive particles accommodated in the opening;
Disposing the plurality of conductive particles formed with the second metal layer on a surface of the electrode;
Fusing the conductive particles to the electrode by heating the plurality of conductive particles disposed on the surface of the electrode to a temperature higher than the melting point of the second metal;
The manufacturing method of the electrode with a terminal containing this. The conductive particles have at least base particles and a first metal layer made of the first metal covering the surface of the base particles,
The manufacturing method of the electrode with a terminal of Claim 15 whose melting | fusing point of said 1st metal is higher than melting | fusing point of said 2nd metal.   The method of manufacturing an electrode with a terminal according to claim 16, wherein the conductive particles include a third metal layer containing palladium or a palladium alloy between the first metal layer and the second metal layer.   The manufacturing method of the electrode with a terminal of Claim 17 whose palladium content rate of a said 3rd metal layer is 90 mass% or more.   The manufacturing method of the electrode with a terminal as described in any one of Claims 16-18 whose particle size of the said base particle is 2-10 micrometers.   The said base particle consists of resin, The manufacturing method of the electrode with a terminal as described in any one of Claims 16-19.   The method for manufacturing an electrode with a terminal according to any one of claims 15 to 20, wherein the first metal includes nickel or a nickel alloy.   The method for manufacturing an electrode with a terminal according to any one of claims 15 to 21, wherein the first metal includes at least one of phosphorus and boron.   The manufacturing method of the electrode with a terminal as described in any one of Claims 15-22 whose nickel content rate of said 1st metal is 85-98 mass%.   The manufacturing method of the electrode with a terminal as described in any one of Claims 15-23 whose tin content rate of said 2nd metal is 30-100 mass%.   The said electrode consists of copper, nickel, palladium, gold | metal | money, silver and these alloys, and an indium tin oxide, The manufacturing method of the electrode with a terminal as described in any one of Claims 15-24. The positions of the plurality of openings of the transfer mold correspond to the positions where the plurality of conductive particles in the electrode are disposed,
By superposing the circuit member and the transfer mold, the conductive particles respectively accommodated in the openings of the transfer mold are arranged on the surface of the electrode,
The conductive particles are fused to the electrode by heating the plurality of conductive particles to a temperature higher than the melting point of the second metal in a state where the circuit member and the transfer mold are overlapped. The manufacturing method of the electrode with a terminal as described in any one of -25.   27. The method of manufacturing an electrode with a terminal according to claim 26, wherein the opening is formed in a tapered shape in which an opening area increases from a back side of the opening toward a surface side of the transfer mold.   The method of manufacturing an electrode with a terminal according to claim 26 or 27, wherein the transfer mold is made of a flexible resin material. It is the electroconductive particle used in the manufacturing method of the connection structure as described in any one of Claims 1-14, or the manufacturing method of the electrode with a terminal as described in any one of Claims 15-28,
Conductive particles having a melting point of the second metal of 120 to 250 ° C. Having at least substrate particles and a first metal layer made of the first metal covering the surface of the substrate particles;
30. The conductive particle according to claim 29, wherein the melting point of the first metal is higher than the melting point of the second metal.   31. The conductive particle according to claim 30, comprising a third metal layer containing palladium or a palladium alloy between the first metal layer and the second metal layer.   The electroconductive particle of Claim 31 whose palladium content rate of the said 3rd metal layer is 90 mass% or more.   The conductive particles according to any one of claims 30 to 32, wherein a particle diameter of the base particle is 1.5 to 10 µm.   The conductive particles according to any one of claims 30 to 33, wherein the base particles are made of a resin.   The conductive particles according to any one of claims 29 to 34, wherein the first metal includes nickel or a nickel alloy.   36. The conductive particle according to any one of claims 29 to 35, wherein the first metal includes at least one of phosphorus and boron.   The electroconductive particle as described in any one of Claims 29-36 whose nickel content rate of said 1st metal is 85-98 mass%.   The conductive particles according to any one of claims 29 to 37, wherein the second metal includes tin or a tin alloy.   The electroconductive particle as described in any one of Claims 29-38 whose tin content rate of said 2nd metal is 30-100 mass%. 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;
The conductive particles according to any one of claims 30 to 39, which are interposed between the first electrode and the second electrode and are fused to at least the first 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: Conductive particles according to any one of claims 29 to 39;
A transfer mold having a plurality of openings at positions corresponding to positions where the plurality of conductive particles are disposed on the electrode surface;
An electrode manufacturing kit with a terminal.   42. The electrode manufacturing kit with a terminal according to claim 41, wherein the opening is formed in a tapered shape in which an opening area increases from a back side of the opening toward a surface side of the transfer mold.   The kit for manufacturing an electrode with a terminal according to claim 41 or 42, wherein the transfer mold is made of a resin material having flexibility. A transfer mold used in the method for producing a connection structure according to any one of claims 1 to 14 or the method for producing an electrode with a terminal according to any one of claims 15 to 28,
A transfer mold having a plurality of openings at positions corresponding to positions at which a plurality of the conductive particles are arranged on the electrode surface.   45. The transfer mold according to claim 44, wherein the opening is formed in a tapered shape in which an opening area increases from a back side of the opening toward a surface side of the transfer mold.   The transfer mold according to claim 44 or 45, comprising a resin material having flexibility.

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