JP6907490B2 - Connection structure and its manufacturing method, manufacturing method of electrode with terminal, and conductive particles, kit and transfer type used for this - Google Patents

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 type used therein.

The method of mounting the liquid crystal driving IC on the glass panel for liquid crystal display can be roughly divided into two types: COG (Chip-on-Glass) mounting and COF (Chip-on-Flex) mounting. In COG mounting, the liquid crystal driving IC is directly bonded onto the glass panel using an anisotropic conductive adhesive containing conductive particles. On the other hand, in COF mounting, liquid crystal driving ICs are bonded to a flexible tape having metal wiring, and they are bonded to a glass panel using an anisotropic conductive adhesive containing conductive particles. The term "anisotropic" as used herein means that the material conducts in the pressurized direction and maintains the insulating property in the non-pressurized direction.

By the way, with the recent increase in the definition of the liquid crystal display, the metal bumps, which are the circuit electrodes of the liquid crystal drive IC, have become narrower in pitch and area, and therefore, the circuits in which the conductive particles of the anisotropic conductive adhesive are adjacent to each other. It may flow out between the electrodes and cause a short circuit. 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 captured between the metal bump and the glass panel decreases, and the connection resistance between the facing circuit electrodes increases. There is a risk of connection failure. Such a tendency becomes more remarkable when less than ^{20,000 conductive particles / mm 2 are charged 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 adhering spherical resin particles to the surface of conductive particles. Even when further charged 70,000 pieces / mm ² or more of the conductive particles per unit area, have been proposed insulating reliability superior insulating coating conductive particles, Patent Document 3, a first insulating particle , An insulating coated conductive particle in which a second insulating particle having a glass transition temperature lower than that of the first insulating particle is attached to the surface of the conductive particle has been proposed.

Japanese Patent No. 4773685 Japanese Patent No. 3869785 Japanese Unexamined Patent Publication No. 2014-17213

By the way, when the connection points of the circuit members to be electrically connected to each other are very small (for example, the bump area ^{is less than 2000 μm 2} ), it is preferable to increase the number of conductive particles in order to obtain stable conduction reliability. For this reason, it has come out even if you put 100,000 / mm ² or more of the conductive particles per unit area. However, when the connection points are minute in this way, it is difficult to balance the conduction reliability and the insulation reliability even if the insulating coated conductive particles described in Patent Documents 1 to 3 are used, and there is still room for improvement. was there.

The present invention has been made in view of the above problems, and is a connection structure having excellent insulation reliability and conduction reliability even if the connection points of circuit members to be electrically connected to each other are minute. It is an object of the present invention to provide a manufacturing method. Another object of the present invention is to provide a method for manufacturing an electrode with a terminal useful for manufacturing the above-mentioned connection structure, and conductive particles, a kit, and a transfer type used for the method.

In order to solve the above problems, the present inventors have investigated the reason why the insulation resistance value is lowered by the conventional method. As a result, in the inventions described in Patent Documents 1 and 2, the covering property 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 particles / mm 2 or less per unit area.} Even so, it was found that the insulation resistance value tends to decrease.

In the invention described in Patent Document 3, in order to compensate for the shortcomings of the inventions described in Patent Documents 1 and 2, the first insulating particles and the second insulating particles having a lower glass transition temperature than the first insulating particles are used. It is attached to the surface of conductive particles. As a result, if the input amount of the conductive particles is ^{about 70,000 particles / mm 2} per unit area, the insulation resistance value can be maintained at a sufficiently high state. However, it was found that the insulation resistance value may be insufficient when the input amount of the conductive particles is 100,000 particles / 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 method for manufacturing 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.
-Prepare a second circuit member with a second electrode that is electrically connected to the first electrode.
-Prepare a plurality of conductive particles having a particle size of 2.0 to 40 μm and a surface made of metal.
-Place the above-mentioned plurality of conductive particles on the surface of the first electrode.
-Fusing the conductive particles 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 metal.
One surface of the first circuit member having the first electrode to which the conductive particles are fused, and one surface of the second circuit member having the second electrode. To form an insulating resin layer between them.
-By heating the laminate containing the first circuit member, the insulating resin layer, and the second circuit member in a pressed state in the thickness direction of the laminate, the first electrode and the second electrode are made of conductive particles. To be electrically connected via and adhere to the first circuit member and the second circuit member.

According to the method for manufacturing the connection structure, by fusing a plurality of conductive particles on the surface of the first electrode, only between the first electrode and the second electrode to be electrically connected to each other. Conductive particles can be placed. As a result, even if the connection portion between the first electrode and the second electrode is minute, it is possible to sufficiently efficiently and stably manufacture a connection structure having excellent insulation reliability and conduction reliability. .. That is, the conductive particles fused to the surface of the first electrode act as bumps (connecting protrusions), so that innumerable conductive particles contained in the anisotropic conductive material have insulating properties as in the prior art. It is possible to highly suppress the occurrence of a short circuit between the electrodes due to the outflow between the adjacent electrodes to be secured.

The present invention provides a method for manufacturing an electrode with a terminal. That is, the method for manufacturing an electrode with a terminal according to the present invention includes the following steps.
-Prepare a circuit member having a substrate and electrodes provided on the substrate.
-Prepare a plurality of conductive particles having a particle size of 2.0 to 40 μm and a surface made of metal.
-Place the above-mentioned plurality of conductive particles on the surface of the electrode.
-Fusing the conductive particles 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 metal.

According to the above-mentioned method for manufacturing an electrode with a terminal, by fusing a plurality of conductive particles on the surface of the electrode, these conductive particles can play a role of bumps (connecting protrusions). As a result, even if the connection point between this electrode and the electrode of another circuit member to be electrically connected to this circuit member is very small, a connection structure having excellent insulation reliability and conduction reliability can be sufficiently provided. It is useful for efficient and stable production.

In the present invention, a transfer type may be used in order to dispose a plurality of conductive particles on the electrode (first electrode) and fuse them to the positions. That is, the method for manufacturing a connection structure or the method for manufacturing an electrode with a terminal according to the present invention is a transfer having a plurality of openings at positions corresponding to positions where a plurality of conductive particles are arranged on the electrode (first electrode). Preparing the mold; further including accommodating conductive particles in multiple openings, by superimposing the circuit member (first circuit member) and the transfer mold on the surface of the electrode (first electrode). Conductive particles housed in each of the openings of the transfer mold are arranged, and a 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 with each other. Conductive particles may be fused to the electrode (first electrode) by heating.

The present invention provides the above transfer type. That is, the transfer type according to the present invention is used in the method for manufacturing the connection structure or the method for manufacturing the electrode with terminals, and is located at a position corresponding to a position on the surface of the electrode where a plurality of conductive particles are arranged. It has multiple openings. According to this transfer type, a plurality of fine conductive particles (particle size 2.0 to 40 μm) can be efficiently arranged and fused at a predetermined position on the electrode surface.

The transfer mold opening is preferably formed in a tapered shape in which the opening area expands from the back side of the opening toward the surface side of the transfer mold. The transfer type is preferably made of a flexible resin material. By adopting these configurations, even if the particle size distribution of the conductive particles has a certain width, a plurality of conductive particles having a narrower particle size distribution can be easily selected and arranged on the electrode surface. Can be done. That is, even if the conductive particles smaller than the size of the transfer type opening are once housed in the opening, they will fall if, for example, the surface on which the opening is formed faces downward, while they are larger than the size of the opening. Conductive particles are not contained in the opening. Conductive particles that match the size of the opening are fitted into the opening, and while maintaining this state, 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 formed on the electrode surface. It can be arranged according to the formation pattern of the opening.

The present invention provides conductive particles. That is, the conductive particles according to the present invention are used in the method for manufacturing the connection structure or the method for manufacturing the electrode with terminals, and have a particle size of 2.0 to 40 μm and a melting point of 120 to 250 ° C. It has a surface made of metal. When a plurality of conductive particles are arranged on the electrode surface, the plurality of conductive particles are fused to predetermined positions on the electrode surface by heating to a temperature higher than the melting point of the metal constituting the surface of the conductive particles. ..

The present invention provides a connection structure. That is, the connection structure according to the present invention is electrically connected to a first circuit member having a first substrate and a first electrode provided on the first substrate; and is electrically connected to the first electrode. The second circuit member having the 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 provided between the member and the second circuit member and adhering to the first circuit member and the second circuit member is provided. According to this connection structure, the conductive particles fused to the surface of the first electrode play the role of bumps (connecting protrusions), so that the connection points between the first electrode and the second electrode are minute. Even so, both insulation reliability and conduction reliability can be achieved at 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 type having a plurality of openings at positions corresponding to positions on the electrode surface where the plurality of conductive particles are arranged. According to this kit, a plurality of fine conductive particles (particle size 2.0 to 40 μm) can be efficiently arranged at predetermined positions on the electrode surface.

In the present invention, the conductive particles preferably include base particles and a metal layer formed on the surface of the base particles. In this case, the metal layer has a multilayer structure having at least a first metal layer covering the surface of the base material particles and a second metal layer forming the outermost layer of the conductive particles, and the melting point of the first metal layer is second. It is preferably higher than the melting point of the metal layer. When a plurality of conductive particles are arranged on the electrode surface, the first metal layer covers the base metal particles by heating 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 of being sufficiently maintained is sufficiently maintained, whereby excellent connection reliability can be obtained, and a plurality of conductive particles can be fused by the second metal layer melted at a predetermined position on the electrode surface.

The particle size of the base particles may be, for example, 1.5 to 10 μm. The base material particles are preferably made of resin. When an impact is applied to the connection portion of the circuit connection, the base particle made of resin easily absorbs the impact and contributes to the improvement of the connection reliability of the circuit connection.

When the conductive particles have a 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. The nickel content of the first metal layer is preferably 85 to 98% by mass from the viewpoint of stably remaining the first metal layer containing nickel or a nickel alloy to obtain sufficiently excellent connection reliability.

When the conductive particles have a second metal layer, the second metal layer is preferably a layer containing tin or a tin alloy from the viewpoint of low melting point, and the tin content of the second metal layer is 30 to 100% by mass. It is preferable to have. As the metal constituting the second metal layer, tin alloys such as In-Sn, In-Sn-Ag, Sn-Bi, Sn-Bi-Ag, Sn-Ag-Cu, and Sn-Cu may be adopted. The second metal layer can be formed by sputtering or electroplating.

The metal layer 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 adopted as the first metal layer and a layer containing tin or a tin alloy is adopted as the second metal layer, a third metal layer (palladium or palladium alloy) is adopted between these layers. By providing a layer containing), it is possible to sufficiently suppress the reaction of nickel contained in the first metal layer and tin contained in the second metal layer to form Sn—Ni-based compounds between these layers. .. More specifically, when the metal layer of the conductive particles has the third metal layer, the palladium contained in the third metal layer is diffused into the second metal layer, and further, a part of the Sn—Ni-based compound. It is taken in and becomes a Sn-Ni-Pd-based compound. As a result, it is possible to prevent a thick layer made of a Sn—Ni compound from being formed between the first metal layer and the second metal layer, and it is possible to maintain good reliability of the conductive particles. The Sn—Ni compound can occur when nickel and tin are in close proximity to each other (when the third metal layer does not exist) and can be exposed to an environment of 100 ° C. It causes a decrease in reliability.

When a layer containing nickel or a nickel alloy is adopted as the first metal layer and a layer containing tin or a tin alloy is adopted as the second 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 the diffusion of tin from the second metal layer into the first metal layer. As a result, it is possible to suppress the thinning of the first metal layer and to prevent the formation of Sn—Ni-based compounds between the first metal layer and the second metal layer. These matters contribute to maintaining good reliability of the conductive particles.

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

According to the present invention, there is provided a connection structure and a method for manufacturing the same, which are excellent in both insulation reliability and conduction reliability even if the connection points of circuit members to be electrically connected to each other are minute. Further, according to the present invention, there is provided a method for manufacturing an electrode with a terminal useful for manufacturing the above-mentioned connection structure, and conductive particles, a kit and a transfer type used for the method.

FIG. 1 is a cross-sectional view schematically showing an embodiment of conductive particles according to the present invention. FIG. 2 is a cross-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 in which 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 conductive particles. It is a cross-sectional view. FIG. 5 is an enlarged view of a part of the connection structure according to the present invention, and schematically another example in which the first electrode and the second electrode are electrically connected by conductive particles. It is a cross-sectional view shown in. FIG. 6 is a cross-sectional view schematically showing an embodiment of the connection structure according to the present invention. 7 (a) to 7 (c) are cross-sectional views schematically showing an example of a process of forming an electrode with a terminal on the first circuit member. 8 (a) is a plan view schematically showing one embodiment of the transfer type according to the present invention, and FIG. 8 (b) is a cross-sectional view taken along the line bb shown in FIG. 8 (a). FIG. 9 is a cross-sectional view schematically showing a state in which conductive particles are trapped in a transfer type recess (opening). FIG. 10A is an SEM photograph showing an example of the transfer type, and FIG. 10B is an SEM photograph showing a state in which conductive particles are arranged in a plurality of openings of the transfer type shown in FIG. 10A. FIG. 10 (c) is an SEM photograph showing a state in which a plurality of conductive particles arranged in a transfer mold are fixed on a substrate through a fusion step. 11 (a) to 11 (d) are examples of a process of forming a connection structure including a first circuit member on which an electrode with a terminal shown in FIG. 7 (c) is formed and a second circuit member. It is sectional drawing which shows typically. 12 (a) and 12 (b) show the process of forming a connection structure including the first circuit member on which the terminalized electrode shown in FIG. 7 (c) is formed and the second circuit member. It is sectional drawing which shows typically the example of. FIG. 13 is a plan view schematically showing a circuit member in which a total of eight conductive particles are fused to each electrode. FIG. 14 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. Unless otherwise specified, the materials exemplified below may be used alone or in combination of two or more. The content of each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified. The numerical range indicated by using "~" indicates a range including the numerical values before and after "~" as the minimum value and the maximum value, respectively. In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value of the numerical range of one step may be replaced with the upper limit value or the lower limit value of the numerical range of another step. In the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

<Conductive particles>
The conductive particles 10A shown in FIG. 1 are spherical particles including the base material particles 1 and the metal layer 3 having a two-layer structure formed on the surface of the base material particles 1. The conductive particles 10A are fused to the electrode surface and used 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 do not adhere to the particle surface. The sphere referred to in the present specification 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, 2.0 to 40 μm, and may be 3 to 20 μm or 3.5 to 10 μm. If the particle size of the conductive particles 10A is 2.5 μm or more, the conductive particles tend to be able to sufficiently absorb the impact even if an impact is applied to the conductive particles, while if the particle size is 15 μm or less, the conductive particles tend to be sufficiently absorbed. The variation in the particle size of the particles can be sufficiently reduced, which makes it easy to achieve both conduction reliability and insulation reliability. The particle size of the conductive particles 10A can be measured by observation using a scanning electron microscope (hereinafter, SEM). That is, the average particle size of the conductive particles can be obtained by measuring the particle size of 300 arbitrary conductive particles by observing with SEM and taking the average value thereof.

[Base particles]
The base particle 1 is made of a spherical and non-conductive material. The particle size 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 particle 1 tends to be able to sufficiently absorb the impact even if an impact is applied to the conductive particles, while if the particle size is 10 μm or less, the base particle 1 tends to be sufficiently absorbed. There is a tendency that the variation in particle size can be made sufficiently small. The particle size of the base particle 1 can be measured by observation using SEM. The average particle size of the base particle 1 is obtained by measuring the particle size of 300 arbitrary base particles by observation using SEM and taking the average value thereof.

The material of the base particle 1 is not particularly limited, but resin or silica can be adopted. Specific examples of these include acrylic resins such as polymethylmethacrylate and polymethylacrylate; polyolefin resins such as polyethylene, polypropylene, polyisobutylene and polybutadiene; glass; silica and the like. When resin particles are used as the base material particles 1, for example, crosslinked acrylic particles, crosslinked polystyrene particles, and the like can be used. Assuming that reflow connection by soldering is performed, the glass transition point (Tg) of the base particle 1 is preferably higher than the melting point of the solder. Taking the commonly used Sn-3 mass% Ag-0.5 mass% Cu as an example, the melting point is 217 to 219 ° C. Therefore, the base particle 1 has a Tg of, for example, 220 ° C. or higher. Material should be adopted. By adopting such a material, even if the solder is melted for reflow connection, if the temperature is less than Tg of the base particle 1, the deformation of the base particle 1 is sufficiently suppressed, so that the conductive particles The base particle 1 contained in 10A and 10B exhibits excellent dimensional stability, which tends to obtain 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 particles 1. The metal layer 3A has a first metal layer 3a containing nickel or a nickel alloy and a second metal layer 3b containing tin or a tin alloy in this order from the base particle 1 side. The metal layer 3A does not necessarily have to cover the entire base particle 1, and may preferably cover 80% or more, more preferably 90% or more of the surface of the base particle 1.

(First metal layer)
The first metal layer 3a is a layer containing nickel or a nickel alloy, and covers the surface of the base particle 1. The nickel content of the first metal layer 3a is, for example, 85 to 98% by mass, and may be 87 to 96% by mass or 90 to 95% by mass. When the nickel content is 85 to 98% by mass, the first metal layer 3a is stable after the second metal layer 3b (a layer containing tin or a tin alloy) described later is bonded to the electrode (see FIG. 4). It remains and tends to maintain high connection reliability. The first metal layer 3a does not necessarily have to cover the entire surface of the base particle 1, preferably 80% or more, more preferably 90% or more of the surface of the base 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 first metal layer 3a is 0.05 μm or more, after the second metal layer 3b (a layer containing tin or a tin alloy) described later is bonded to the electrode (see FIG. 4), the first metal layer 3a Remains stable, which tends to maintain high connection reliability. If the thickness of the first metal layer 3a is less than 0.05 μm, the nickel contained in the first metal layer 3a is contained in the second metal layer 3b after the second metal layer 3b is bonded to the electrode. Alternatively, it diffuses into the tin alloy, which tends to form a discontinuous film, resulting in reduced connection reliability.

The first metal layer 3a may contain at least one of phosphorus and boron, and may particularly contain phosphorus. As a result, it is possible to prevent nickel contained in the first metal layer 3a from diffusing into the tin or tin alloy contained in the second metal layer 3b after the second metal layer 3b is bonded to the electrode. As a result, it is possible to sufficiently suppress the decrease in the thickness of the first metal layer 3a.

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 carried out by a known method. For example, the surface of the base particle 1 may be palladium-catalyzed and then electroless nickel plating may be carried out. More preferably, phosphorus can be co-deposited 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). ) Can be formed in the first metal layer 3a. Alternatively, by using a boron-containing compound such as dimethylamine borane, sodium borohydride, or potassium borohydride as the reducing agent, boron can be co-deposited, and an alloy containing nickel and boron (nickel-boron) can be used. 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, which covers the surface of the first metal layer 3a and serves as a solder. The second metal layer 3b does not necessarily have to cover the entire surface of the first metal layer 3a, and preferably covers 80% or more, more preferably 90% or more of the surface of the first metal layer 3a. Just do it. The second metal layer 3b constitutes the outermost layer of the conductive particles 10A and is bonded to the electrode (see FIG. 4).

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 and the like can be adopted. , Specific examples are given below.
-In-Sn (In 52% by mass, Bi48% by mass, melting point 118 ° C)
-In-Sn-Ag (In 20% by mass, Sn77.2% 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 (Sn42% by mass, Bi57% by mass, Ag1% by mass, melting point 139 ° C.)
-Sn-Ag-Cu (Sn96.5% by mass, Ag3% by mass, Cu0.5% by mass, melting point 217 ° C)
-Sn-Cu (Sn99.3% by mass, Cu0.7% by mass, melting point 227 ° C)

The tin alloy can be selected according to the connecting temperature. For example, when it is desired to connect at a low temperature, it can be connected at 150 ° C. or lower by using In—Sn or Sn—Bi as the tin alloy constituting the second metal layer 3b. By using a material having a high melting point (for example, Sn-Ag-Cu or Sn-Cu) as the tin alloy constituting the second metal layer 3b, the second metal layer 3b is bonded to the electrode, even after being left at a high temperature. There is a tendency to achieve high reliability. The layer containing tin or a tin alloy may contain a trace amount of metals such as Ni, Mn, Sb, Al, and Zn, if necessary.

The thickness of the second metal layer 3b is, for example, in the range of 0.03 to 10 μm, and may be in the range of 0.05 to 5 μm or 0.1 to 2 μm. When the thickness of the second metal layer 3b is 0.03 μm or more, high reliability tends to be achieved when the second metal layer 3b is joined to the electrode. From the viewpoint of suppressing aggregation of the conductive particles 10A and efficiently producing the conductive particles 10A, the upper limit of the thickness of the second metal layer 3b may be about 10 μm as described above.

The second metal layer 3b may contain Ag, Cu, Ni, Bi, Zn, Pd, Pb, Au, P, B or two or more alloys selected from these, and among these, Ag or Cu may be contained from the following viewpoints. May include. 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 bonding strength with the electrode is improved to improve the connection reliability. The effect of being obtained is achieved.

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, while if it is 10% by mass or less, the melting point is lowered and the wettability of the solder is improved, resulting in bonding. The connection reliability of the unit tends to be good.

The Ag 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. When the Ag content is 0.05% by mass or more, good solder connection reliability can be easily obtained, while when it is 10% by mass or less, the melting point is lowered and the wettability of the solder is improved, resulting in bonding. The connection reliability of the unit tends to be good. When the second metal layer 3b contains Ag, Ag ₃ Sn is formed in the second metal layer 3b, and this is dispersed in the solder to improve the strength against impact of the solder.

The second metal layer 3b can be formed by sputtering, electroless plating or electrolytic plating. Of these, sputtering or electroless plating is preferable from the viewpoint of film thickness uniformity. Further, in electrolytic plating, as the particle size becomes smaller, particles tend to aggregate with each other during electrolytic plating, and from this point as well, sputtering or electroless plating is preferable. When the second metal layer 3b is formed by electroless plating, the tin content of the second metal layer 3b tends to be 99% or more. Therefore, in order to control the content of other metals in the second metal layer 3b, the second metal layer 3b may be formed by sputtering or electroplating.

There are two types of electroless tin plating, a substitution type and a reduction type. Of these, it is preferable to form the second metal layer 3b by the reduction type electroless tin plating. When a reduction type electroless tin plating solution is used, a film is formed in a state where corrosion of the base layer is suppressed, so that the adhesion between the first metal layer 3a and the film (second metal layer 3b) is maintained. It is easy to obtain good solder connection reliability.

The plating solution used for electroless tin plating contains acid. This acid functions as a pH regulator and a stabilizer for tin ions. Examples of this acid include inorganic acids such as hydrochloric acid, sulfuric acid, nitrate, borohydrogenic acid and phosphoric acid; carboxylic acids such as formic acid, acetic acid, propionic acid and butyric acid; alkane sulfonic acids such as methanesulfonic acid and ethanesulfonic acid; benzene. Examples thereof include water-soluble organic acids such as aromatic sulfonic acids such as sulfonic acid, phenol sulfonic acid and cresol sulfonic acid. Of these, sulfuric acid or hydrochloric acid may be used from the viewpoint of the formation rate of the second metal layer 3b, the solubility of the tin compound, and the like. The acid concentration is, for example, 1 to 50% by mass and may be in the range of 5 to 40% by mass or 10 to 30% by mass. Within the above range, the copper-tin alloy layer and the nickel-tin alloy layer tend to be easily formed.

The tin compound contained in the electroless tin plating solution can be used without particular limitation from tin salts, tin oxides, etc. as long as it is soluble in an acidic solution, but from the viewpoint of its solubility, it can be used with the above acids. It may be a salt. For example, stannous sulfate, stannous sulfate, stannous borofluoride, stannous borofluoride, stannous fluoride, stannous fluoride, stannous nitrate, stannous nitrate, stannous chloride. , Stannous chloride, stannous formate, stannous formate, stannous acetate, stannous acetate and the like can be used. The concentration of the tin compound in the electroless tin plating solution may be in the range of 0.05 to 10% by mass, may be in the range of 0.1 to 5% by mass, and may be in the range of 0.5 to 3% by mass. It may be a range. Within the above range, the copper-tin alloy layer and the nickel-tin alloy layer tend to be easily formed.

The complexing agent contained in the electroless tin plating solution facilitates the formation of a tin plating layer on the surface by coordinating with the first metal layer 3a to form a chelate. For example, thiourea derivatives such as thiourea, 1,3-dimethylthiourea, 1,3-diethyl-2-thiourea, and thioglycolic acid can be used. The concentration of the complexing agent in the electroless tin plating solution may be in the range of 1 to 50% by mass, 5 to 40% by mass, or 10 to 30% by mass. Within this range, the adhesiveness with the second metal layer 3b tends to be ensured without reducing the formation rate of the tin plating layer.

In addition to the above components, the electroless tin plating solution may contain additives such as stabilizers and surfactants. The stabilizer is an additive for maintaining the concentration of each component required for the reaction in the vicinity of the surface of the first metal layer 3a. For example, glycols such as ethylene glycol, diethylene glycol and propylene glycol, glycol ethers such as cellosolve, carbitol and butyl carbitol can be exemplified. The concentration of the stabilizer in the electroless tin plating solution may be 1 to 80% by mass, 5 to 60% by mass, or 10 to 50% by mass. Within the above range, the concentration of each component required for the reaction tends to be easily maintained in the vicinity of the surface of the first metal layer 3a. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants and the like.

When the second metal layer 3b is formed by electrolytic plating, a commercially available tin plating solution for electrolysis may be used. The plating apparatus is not particularly limited as long as it is a barrel plating apparatus, but an oblique barrel plating apparatus tends to be able to suppress agglomeration of particles.

When the second metal layer 3b is formed by sputtering, a commercially available sputtering apparatus can be used and is not particularly limited, but the sputtering apparatus by the barrel method is not particularly limited. A barrel sputtering device having a cylindrical shape, an oblique shape, a polygonal shape, or the like tends to be able to suppress agglomeration of particles.

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

The particle size of the conductive particles 10B shown in FIG. 2 is, for example, 2.0 to 40 μm, and may be 3 to 20 μm or 3.5 to 10 μm, similar to the conductive particles 10A. If the particle size of the conductive particles 10B is 2.0 μm or more, the conductive particles 10B tend to be able to sufficiently absorb the impact even if an impact is applied to the conductive particles 10B, while if the particle size is 40 μm or less, the conductive particles 10B tend to be able to sufficiently absorb the impact. The variation in the particle size of the conductive particles 10B can be sufficiently reduced, which makes it easy to achieve both conduction reliability and insulation reliability. The particle size of the conductive particles 10B can be measured by observation using an SEM as in the case of 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 step, and is preferably an electroless plating type palladium layer. The electroless palladium plating may be performed by using either a substitution type (type without a reducing agent) or a reduction type (type containing a reducing agent). Examples of electroless palladium plating include APP (Ishihara Yakuhin Kogyo, trade name) for the reduced type and MCA (trade name, manufactured by World Metal Co., Ltd.) for the replacement type. When the substituted type and the reduced type are compared, the reduced type is particularly preferable because it tends to have fewer voids. Compared with the substitution type, which precipitates while dissolving the inner metal, the reduction type is preferable because the covering area tends to increase.

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 on the outside of the first metal layer 3a and a second palladium plating film provided on the outside of this film. It is preferable that the first palladium plating film is a substitution or electroless palladium plating film having a purity of 99% by mass or more, and the second palladium plating film is 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 substituted or reduced electroless palladium plating film having a purity of 99% by mass or more is independently formed as the third metal layer 3c, Pd is contained in the Sn—Cu—Ni-based compound or the Sn—Ni-based compound. Although the effect of suppressing the growth of these compounds can be obtained, the reduced electroless palladium plating film having a purity of 90% by mass or more and less than 99% by mass is more effective in suppressing the growth of these compounds. .. On the other hand, when a reduced electroless palladium plating film having a purity of 90% by mass or more and less than 99% by mass is independently formed as the third metal layer 3c, there is an advantage that the phosphorus content in the electroless palladium plating film can be increased. There is. On the other hand, it is difficult to deposit a film having a uniform thickness on all of the base particles 1 on which the first metal layer 3a is formed on the surface, and a film containing phosphorus (electroless palladium-phosphorus film) is formed. Particles that are not formed or particles with a significantly thin coating are likely to occur. This phenomenon tends to appear more easily as the particle size of the conductive particles becomes smaller. 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 of the first metal layer 3a. .. On the other hand, the substituted or reduced electroless palladium plating film having a purity of 99% by mass or more has more precipitation 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. This is likely to occur, and the first metal layer 3a precipitates on all of the base particles 1 formed on the surface with a sufficiently uniform thickness, and precipitates independently of the particle size of the base particles 1. After a substitution or reduction type electroless palladium plating film having a purity of 99% by mass or more is formed, a reduction type electroless palladium plating film having a purity of 90% by mass or more and less than 99% by mass is likely to precipitate on the surface thereof. Precipitation occurs regardless of the particle size of the base particle 1. For this reason, the third metal layer 3c includes a first palladium plating film (substitution or electroless palladium plating film having a purity of 99% by mass or more) provided on the outside of the first metal layer 3a and the outside of this film. It is preferable to have a second palladium plating film (electroless palladium plating film having a purity of 90% by mass or more and less than 99% by mass) provided in the above.

The third metal layer 3c may not remain as a layer due to the diffusion of palladium into the second metal layer 3b after the second metal layer 3b is bonded to the electrode. By diffusing palladium into the second metal layer 3b (a layer containing tin or a tin alloy), the Sn-Cu-Ni-Pd-based compound or the Sn-Ni-Pd-based compound becomes the first metal layer 3a and the second metal. It can be formed between the layer 3b and 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 even more preferably 0.05 to 0.5% by mass. When the Pd content of the above compound is 0.01% by mass or more, it is easy to obtain the effect of suppressing the growth of the Sn—Cu—Ni-based compound or the Sn—Ni-based compound in a high temperature environment of about 100 ° C. When the Pd content is 3% by mass or less, the third metal layer 3c (palladium-plated coating) is likely to diffuse into the solder and disappear, and the drop impact reliability tends to be improved.

The third metal layer 3c also functions as a layer for ensuring the wet spread 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, the Sn-Cu-Ni-Pd-based compound or the Sn-Ni-Pd-based compound described above will be used after the second metal layer 3b is bonded to the electrode. The Pd content is likely to be 0.01% by mass or more, and as a result, the effect of suppressing the growth of Sn—Cu—Ni-based compound or Sn—Ni-based compound in a high temperature environment of about 100 ° C. is easily obtained, while 0. If it is 5.5 μm or less, the third metal layer 3c (palladium-plated film) diffuses into the solder and easily disappears, which tends to improve the drop impact reliability.

<Electrode with terminal>
FIG. 3 is a perspective view schematically showing the electrode 35 with a terminal according to the present embodiment. That is, the 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 (projections for connection) on the surface of the electrode 32. Fulfill. The first circuit member 30 includes a first circuit board 31 and a first electrode 32 arranged on the surface 31a thereof. As shown in FIG. 3, the first metal layer 3a of the conductive particles 10A is fused to the first electrode 32 through a step of melting once and then solidifying. As described above, the term "fused" as used herein refers to a state in which at least a part of the first metal layer 3a is melted by heat and then solidified to form conductive particles bonded to the surface of the electrode. Means. Although the conductive particles 10A are used here, the conductive particles 10B may be used 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, and copper / palladium. / Gold, copper / tin, copper / silver, indium tin oxide and other electrodes can be mentioned. The first electrode 32 can be formed by electroless plating, electroplating or sputtering.

<Connection structure>
FIG. 4 is an enlarged sectional view schematically showing a part of the connection structure 50A according to the present embodiment. That is, the 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 arranged on the surface 41a thereof.

As shown in FIG. 4, the connection structure 50A includes conductive particles 10A interposed between the first circuit member 30, the second circuit member 40, and 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 first metal layer 3a of the conductive particles 10A is fused to the first electrode 32 and is in contact with the surface of the second electrode 42. The insulating resin layer 55 filled between the circuit members 30 and 40 maintains a state in which the first circuit member 30 and the second circuit member 40 are adhered to each other, and the first electrode 32 and the second electrode The 42 remains electrically connected.

FIG. 5 is a cross-sectional view schematically showing a modified example of the connection structure 50A shown in FIG. In the connection structure 50B according to this modification, the first metal layer 3a of the conductive particles 10A is fused to the first electrode 32 and also to the second electrode 42.

Specific examples of one of the circuit members 30 and 40 include chip components such as IC chips (semiconductor chips), resistor chips, capacitor chips, and driver ICs; rigid type package substrates. These circuit members are provided with circuit electrodes, and are generally provided with a large number of circuit electrodes. Specific examples of the other of the circuit members 30 and 40 include wiring boards such as flexible tape boards having metal wiring, flexible printed wiring boards, and glass boards on which indium tin oxide (ITO) is vapor-deposited.

The connection structure 50A shown in FIG. 6 includes a plurality of connection portions formed by the conductive particles 10A shown in FIG. 5 (three are shown in FIG. 6). Since the electrical connection between the electrodes 32 and 42 facing each other is secured 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 the conductive particles. You just have to adopt the one. 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 significantly improved.

Applications of the connection structures 50A and 50B include devices such as liquid crystal displays, personal computers, mobile phones, smartphones, and tablets.

<Manufacturing method of electrodes with terminals>
A method of manufacturing the electrode 35 with a terminal will be described with reference to FIGS. 7 to 10. Here, a method of manufacturing the terminal-attached electrode 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. 7 (a) to 7 (c) are cross-sectional views schematically showing an example of a process of forming an electrode with a terminal on the first circuit member.

(Preparation of transfer type)
First, a transfer mold 60 for arranging and fusing a plurality of conductive particles 10A on the surface of the electrode 32 is prepared. 8 (a) is a plan view of the transfer type 60, and FIG. 8 (b) is a cross-sectional view taken along the line BB shown in FIG. 8 (a). FIG. 9 is a cross-sectional view showing a state in which the conductive particles 10A are housed in the plurality of recesses (openings) 62 of the transfer mold 60. The plurality of recesses 62 are provided at positions corresponding to the positions on the surface of the electrode 32 on which the conductive particles 10A should be arranged.

The recess 62 of the transfer mold 60 is preferably formed in a tapered shape in which the opening area expands from the bottom 62a side (back side) of the recess 62 toward the surface 60a side of the transfer mold 60. That is, as shown in FIG. 9, the width of the bottom portion 62a of the recess 62 (width a in FIG. 9) is preferably narrower than the width of the opening on the surface 60a of the recess 62 (width b in FIG. 9). The size (taper angle and depth) of the recess 62 may be set according to the size of the conductive particles 10A to be arranged on the surface of the electrode 32. That is, when the conductive particles 10A to be arranged on the surface of the electrode 32 are housed in the recess 62, the height of the conductive particles 10A protruding from the recess 62 (the distance from the surface 60a of the transfer mold 60 to the upper end of the conductive particles 10A (FIG. The distance c)) in 9 is preferably 1 μm or more, more preferably 2 μm or more, from the viewpoint of reliably fusing the conductive particles 10A to the surface of the electrode 32.

As the material constituting the transfer mold 60, for example, an inorganic material such as a metal such as silicon, various ceramics, glass, and stainless steel, and an organic material such as various resins can be used. Of these, from the viewpoint of holding the conductive particles 10A in the recess 62 in a state of being contained, it is preferably made of a flexible resin material. The recess 62 of the transfer mold 60 can be formed by a known method such as a photolithography method.

By using the transfer type 60, even if the particle size distribution of the conductive particles 10A has a certain width, a plurality of conductive particles 10A having a narrower particle size distribution can be easily selected and these can be applied to the surface of the electrode 32. Can be placed. That is, even if the conductive particles 10A smaller than the size of the recess 62 of the transfer mold 60 are once housed in the recess 62, they will fall if the surface on which the recess 62 is formed faces downward, while the size of the recess 62 is larger than that of the recess 62. The large conductive particles 10A are not housed in the recess 62. Conductive particles 10A matching the size of the recess 62 are fitted into the recess 62, and while maintaining this state, the surface on which the recess 62 of the transfer mold 60 is formed is brought into contact with the electrode surface, whereby a plurality of conductive particles 10A are brought into contact with the electrode surface. The conductive particles 10A can be arranged according to the formation pattern of the recess 62 (see FIGS. 7 (a) and 7 (b)). Although the recess 62 (bottomed opening) is illustrated here as the opening in which the conductive particles 10A are arranged, the opening may be formed by a hole penetrating from the front surface to the back surface of the transfer mold.

FIG. 10A is an SEM photograph showing an example of a transfer type actually produced by the present inventors. FIG. 10B is an SEM photograph showing a state in which conductive particles are arranged in the plurality of openings of the transfer type shown in FIG. 10A. FIG. 10 (c) is an SEM photograph showing a state in which a plurality of conductive particles arranged in a transfer mold are fixed on a substrate through a fusion step. The transfer type shown in FIG. 10 (a) appears to have a mesh-like opening with no bottom, but the opening of this transfer type has a bottom.

(Arrangement and fusion of conductive particles)
FIG. 7A is a cross-sectional view schematically showing a state in which the transfer mold 60 containing the conductive particles 10A in each recess 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 10A housed in the recess 62 of the transfer mold 60 are brought into contact with the surface of the first electrode 32. FIG. 7C is a cross-sectional view schematically showing a state in which the conductive particles 10A 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 higher than the melting point of the first metal layer 3a of the conductive particles 10A (for example, 120 to 250 ° C.). Then, by cooling, the conductive particles 10A can be fused to a predetermined position of the first electrode 32. As a result, the electrode 35 with a terminal is obtained (see FIGS. 3 and 7 (c)).

<Manufacturing method of connection structure>
A method of manufacturing the connection structure 50 will be described with reference to FIGS. 11 (a) to 11 (d). These figures schematically show an example of the 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 which shows. 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 this is laminated on the surface of the first circuit member 30. , The surface of the first circuit member 30 (including the terminal-equipped electrode 35) is covered (see FIG. 11B). The second circuit member 40 is arranged on the laminated insulating resin film 55p so that the surfaces on which the second electrodes 42 are formed face each other (see FIG. 11C). After that, the electrode 35 is brought into contact with the second electrode 42 by applying pressure in the thickness direction of the laminated body 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, the insulating resin layer 55 made of a cured product of the 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. .. Although the case where the insulating resin film 55p is arranged on the surface of the first circuit member 30 is illustrated here, instead of this, a paste-like insulating resin composition is applied to the surface of the first circuit member 30. May be good.

A modified example of the method for manufacturing the connection structure 50 will be described with reference to FIGS. 12 (a) and 12 (b). In this modification, the insulating resin film 55p is arranged between the first circuit member 30 on which the terminal-attached electrode 35 is formed and the second circuit member 40 (see FIG. 12A), and then thereafter. The electrode 35 is brought into contact with the second electrode 42 by applying pressure in the thickness direction of the laminated body of these members (directions of arrows A and B shown in FIG. 12B). 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, the insulating resin layer 55 made of a cured product of the 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 The manufacturing method is provided.

Hereinafter, the contents of the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

<Example 1>
[Preparation of conductive particles]
(Step a) Pretreatment step Atotech Neogant 834 (manufactured by Atotech Japan Co., Ltd.), which is a palladium catalyst, is added to 2 g of crosslinked polystyrene particles (manufactured by Nippon Catalyst Co., Ltd., trade name "Soliostar") having an average particle size of 3.0 μm. Name) was added to 100 mL of a palladium-catalyzed solution containing 8% by mass, and the mixture was stirred at 30 ° C. for 30 minutes. Next, after filtering with a membrane filter of φ3 μm (manufactured by Millipore Co., Ltd.), resin particles were obtained by washing with water. Then, resin particles were added to a 0.5 mass% dimethylamine borane solution adjusted to pH 6.0 to obtain resin particles having an activated surface. Then, the resin particles whose surface was activated were immersed in 20 mL of distilled water and then ultrasonically dispersed to obtain a resin particle dispersion liquid.

(Step b) Formation of First Metal Layer The resin particle dispersion obtained in step a was diluted with 1000 mL of water heated to 80 ° C., and then 1 mL of a 1 g / L bismuth nitrate aqueous solution was added as a plating stabilizer. .. Next, electroless nickel for forming the first metal layer having the following composition (an aqueous solution containing the following components, 1 mL of 1 g / L bismuth nitrate aqueous solution was added per 1 L of the plating solution) was added to the dispersion liquid containing 2 g of resin particles. 500 mL of the plating solution was added dropwise at a dropping rate of 5 mL / min. After 10 minutes had passed after the completion of the dropping, the dispersion liquid to which the plating liquid was added was filtered. The filtrate was washed with water and then dried in a vacuum dryer at 80 ° C. In this way, a first layer made of a nickel-phosphorus alloy film (nickel concentration 93% by mass, balance phosphorus) having a film thickness of 0.5 μm shown in Table 1 was formed. The particle A obtained by forming the first layer was 6 g, and the outer diameter was 4 μm.
(Electroless nickel plating solution for forming the first layer)
Nickel sulfate: 400 g / L
Sodium hypophosphate: 150 g / L
Acetic acid: 120 g / L
Bismuth nitrate aqueous solution (1 g / L): 1 mL / L

(Step c) Formation of second metal layer A solder layer (second metal layer) having a composition of Sn-3.0Ag-0.5Cu is averaged on 6 g of particles on which the first metal layer (nickel) is formed by barrel sputtering. 0.5 μm was formed. In the barrel sputtering, particles forming the first metal layer (nickel) are placed in a cylindrical barrel having a target having a composition of Sn-3.0Ag-0.5Cu inside the rotation drive unit, and the barrel is subjected to the barrel sputtering. After depressurizing the inside to 1 × 10 ^-4 Pa or less, argon was flowed at a constant flow velocity so that the inside of the barrel became 1 Pa. Then, the barrel was rotated and inverted to roll and stir the particles. Furthermore, the particles were directly vibrated to suppress the agglomeration of the particles. Then, a voltage was applied to the target to form a sputter layer on the surface of the particles. After sputtering was performed until the sputter layer having a composition of Sn-3.0Ag-0.5Cu became 0.5 μm, the inside of the barrel was returned to atmospheric pressure, and conductive particles were taken out. The conductive particles obtained by forming the second metal layer were 10 g, and the outer diameter was 5 μm. The particles were taken out and agglomerates were removed by passing through a sieve having a diameter of 7 cm, which has an opening diameter of 8 μm square.

[Manufacturing electrodes with terminals]
(Step d)
Conductive particles (outer diameter 5 μm) obtained through step c have an opening diameter of 6 μm square, a bottom diameter of 3 μm square, and a depth of 5 μm (the bottom diameter of 3 μm square is at the center of the opening diameter of 6 μm square when the opening is viewed from the top surface. It was placed in a transfer type recess (which shall be located). A polyimide film (thickness 100 μm) was used as the transfer type film.

A chip (1.7 x 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) and a transfer mold in which conductive particles are arranged in recesses. They were faced to each other and the copper bumps and the conductive particles were brought into contact with each other. A chip with an electrode with a terminal is used by using a vacuum reflow soldering device [Vacuum reflow soldering device VADU100 manufactured by PINK (Germany)] and holding it at a formic acid concentration of 2% by mass, a pressure of 2000 Pa, and 230 ° C for 1 minute for joining. (1.7 × 1.7 mm, thickness: 0.5 mm) was obtained. More specifically, as shown in FIG. 13, a chip C1 with an electrode with a terminal was obtained in which eight conductive particles were arranged on a copper bump at a pitch of 8 μm. In the same manner as this, chips C2 and C3 (1.7 × 1.7 mm, thickness: 0.5 mm) having the following configurations were obtained. FIG. 14 is a plan view schematically showing a chip C2 (circuit member) in which four conductive particles are arranged on a copper bump at a pitch of 8 μm.
・ Chip C1… Area 15 μm × 30 μm, space 10 μm, height: 10 μm, number of bumps 362, number of conductive particles on copper bumps ・ Chip C2… area 15 μm × 15 μm, space 10 μm, height: 10 μm, number of bumps 362, Number of conductive particles on the copper bump 4 ・ Chip C3 ... Area 15 μm × 30 μm, space 6 μm, height: 10 μm, number of bumps 362, number of conductive particles on the copper bump 8

[Preparation of connection structure]
(Step e)
Copolymer of 100 g of phenoxy resin (manufactured by Union Carbide, trade name "PKHC") 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 (10,000) 75 g 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 the mixture was stirred to obtain an adhesive solution. .. The obtained adhesive solution is applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) using a roll coater, and dried by heating at 90 ° C. for 10 minutes to obtain an adhesive film having a thickness of 10 μm. (Insulating resin film) was prepared on a separator.

Next, using the produced adhesive film, a connection between a chip with an electrode with a terminal (1.7 x 1.7 mm, thickness: 0.5 mm) and a glass substrate with an IZO circuit (thickness: 0.7 mm). The connection structure was obtained by following the procedure i) to iii) shown below.
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 bump of the chip and the glass substrate with the IZO circuit were aligned.
iii) This connection was made by heating and pressurizing 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 composition of conductive particles>
A cross section was cut out by an ultramicrotome method so as to pass near the center of the obtained conductive particles. Observation was performed at an arbitrary magnification using a transmission electron microscope device (hereinafter abbreviated as "TEM device", manufactured by JEOL Ltd., trade name "JEM-2100F"). From the obtained image, the thickness of each coating film was measured in the radial direction from the center of the conductive particles. Five conductive particles were measured at five points each, and the average value of a total of 25 points was taken as the film thickness. In addition, the element content (purity) 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 carried out as follows.

(Conduction resistance test-moisture absorption and 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 and heat resistance test (leaved for 100, 300, 500, 1000, 2000 hours under the conditions of temperature 85 ° C. and humidity 85%). The value of was measured for 20 samples, and the average value thereof was calculated. The evaluation was performed using the above-mentioned chips C1 and C2. From the obtained average value, the conduction resistance was evaluated according to the following criteria. The results are shown in Table 2. If the following criteria A or B are satisfied after 500 hours of the moisture absorption and heat resistance test, it can be said that the conduction resistance is good.
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 is 20Ω or more

(Conduction resistance test-high temperature standing 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 (leaving 100, 300, 500, 1000 hours at a temperature of 100 ° C.) are 20 samples. Was measured, and the average value thereof was calculated. The evaluation was performed using the above-mentioned chip C1. From the obtained average value, the conduction resistance was evaluated according to the following criteria. The results are shown in Table 2. If the criteria A or B below are satisfied after 100 hours of the high temperature standing test, it can be said that the conduction resistance is good.
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 is 20Ω or more

(Insulation resistance test)
Regarding the insulation resistance between the chip electrodes, the initial value of the insulation resistance and the value after the migration test (100, 300, 500, 1000 hours left under the conditions of temperature 60 ° C., humidity 90%, 20V application) were measured for 20 samples. and, in all 20 samples was calculated the ratio of the sample insulation resistance is 10 ⁹ Omega more. The evaluation was performed using the above-mentioned chips C1 and C3. The insulation resistance was evaluated from the obtained ratio according to the following criteria. The results are shown in Table 2. If the following criteria A or B are satisfied after 500 hours of the moisture absorption and heat resistance test, it can be said that the insulation resistance is good.
A: The ratio of insulation resistance value of 109Ω or more is 100%
B: The ratio of insulation resistance value of 109Ω or more is 90% or more and less than 100% C: The ratio of insulation resistance value of 109Ω or more is 80% or more and less than 90% D: The ratio of insulation resistance value of 109Ω or more is 50% or more and less than 80% E: The ratio of insulation resistance value of 109Ω or more is less than 50%

<Example 2>
In (step c) of Example 1, instead of the target having the composition of Sn-3.0Ag-0.5Cu, the target was changed to the target of Sn-Bi (Sn43% by mass, Bi57% by mass) in Table 1. Further, in (step e) of Example 1, instead of heating and pressurizing from above the chip under the conditions of iii) 190 ° C., 40 gf / bump, 10 seconds, above the chip under the conditions of 150 ° C., 40 gf / bump, 10 seconds. Conductive particles, electrodes with terminals, a connection structure, and evaluation of the conductive particles and the connection structure were carried out in the same manner as in Example 1 except that the particles were heated and pressurized. 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 steps a and b of Example 1, 6 g of the particles forming the first metal layer (nickel) was diluted with 200 mL of water heated at 50 ° C., and 1 g / L bismuth nitrate aqueous solution was used as a plating stabilizer. 0.2 mL was added, and 100 mL of the electroless palladium plating solution for forming the third metal layer having the following composition was added dropwise at a dropping rate of 1 mL / min. After 10 minutes had passed after the completion of the dropping, the dispersion liquid to which the plating liquid was added was filtered. The filtrate was washed with water and then dried in a vacuum dryer at 80 ° C. In this way, a third metal layer made of a palladium plating film having a thickness of 0.1 μm (palladium purity 100%) was formed. The particles obtained by forming the first metal layer (nickel) 0.5 μm and the third metal layer (palladium) 0.1 μm on the outside of the acrylic particles in this order are 7 g, and the outer diameter is 4. It was 2 μm. Subsequently, the same operation as in (Step c) of Example 1 was performed, and the first metal layer (nickel) 0.5 μm, the third metal layer (palladium) 0.1 μm, and the third metal layer (palladium) 0.1 μm and the third metal layer (palladium) 0.1 μm on the outside of the acrylic particles in this order from the inside. Particles having a dimetal layer (Sn-3.0Ag-0.5Cu) of 0.5 μm and an outer diameter of 5.2 μm were prepared. From this point onward, the same operations as in (Step d) and subsequent steps of Example 1 were carried out to fabricate the electrodes with terminals, fabricate the connection structure, and evaluate the conductive particles and the connection structure. 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: 7 g / L
EDTA.2 sodium: 100 g / L
Citric acid / 2 sodium: 100 g / L
Sodium formate: 20 g / L
pH: 6

<Example 4>
In the same manner as in Example 3, after performing steps a and b of Example 1, a third metal layer composed of a palladium plating film having a thickness of 0.1 μm (palladium purity 100%) is formed, and acrylic particles are formed. Particles composed of a first metal layer (nickel) of 0.5 μm and a third metal layer (palladium) of 0.1 μm were prepared on the outside in this order from the inside. After that, the same operation as in (Step c) of Example 1 was performed, and instead of the target having the composition of Sn-3.0Ag-0.5Cu, Sn-Bi (Sn43% by mass, Bi57% by mass) in Table 1 was used. From the inside, the first metal layer (nickel) 0.5 μm, the third metal layer (palladium) 0.1 μm, and the second metal layer [Sn-Bi (Sn43% by mass, Bi57% by mass) 0. A particle having [5 μm] and having an outer diameter of 5.2 μm was prepared. After that, the same operation as in (Step d) and subsequent steps of Example 1 was performed to obtain an electrode with a terminal. After that, iii) instead of heating and pressurizing from above the chip under the conditions of 190 ° C., 40 gf / bump, 10 seconds, except that heating and pressurizing from above the chip under the conditions of 150 ° C., 40 gf / bump, 10 seconds. A connection structure was produced in the same manner as in Example 1 (step e). The conductive particles and the connecting structure were evaluated in the same manner as in Example 1. The conditions of the produced conductive particles and the like are summarized in Table 1. The evaluation results are shown in Table 2.

<Example 5>
In the same manner as in Example 3, the first metal layer (nickel) 0.5 μm, the third metal layer (palladium) 0.1 μm, and the second metal layer (Sn-3.0Ag-) are placed on the outside of the acrylic particles in this order from the inside. Particles having 0.5 Cu) 0.5 μm and an outer diameter of 5.2 μm were prepared. Subsequently, the same operation as in (Step d) of Example 1 was performed, and instead of the copper bump of Example 1 (Step d), the copper bump was replaced with electroless nickel plating (thickness: 0.5 μm). Gold plating (thickness: 0.05 μm) was sequentially applied (the area, space, height, and number of bumps of the bumps after electroless nickel plating and replacement gold plating are the same as those of the copper bumps of Example 1), copper / Nickel / gold bumps were used. Except for this, the electrode with a terminal was manufactured, the connection structure was manufactured, and the conductive particles and the connection structure were evaluated in the same manner as in Example 1. The conditions of the produced conductive particles and the like are summarized in Table 1. The evaluation results are shown in Table 2.

<Example 6>
In the same manner as in Example 3, the first metal layer (nickel) 0.5 μm, the third metal layer (palladium) 0.1 μm, and the second metal layer (Sn-3.0Ag-) are placed on the outside of the acrylic particles in this order from the inside. Particles having 0.5 Cu) 0.5 μm and an outer diameter of 5.2 μm were prepared. Subsequently, the same operation as in (Step d) of Example 1 was performed, and instead of the copper bumps of Example 1 (Step d), electroless nickel plating (thickness: 0.5 μm) was performed on the copper bumps. Electroless palladium plating (thickness: 0.1 μm) and replacement gold plating (thickness: 0.05 μm) were applied in sequence (electroless nickel plating, palladium plating, bump area, space, height after replacement gold plating, The number of bumps was the same as that of the copper bumps of Example 1), and copper / nickel / palladium / gold bumps were used. Except for this, the electrode with a terminal was manufactured, the connection structure was manufactured, and the conductive particles and the connection structure were evaluated in the same manner as in Example 1. The conditions of the produced conductive particles and the like are summarized in Table 1. The evaluation results are shown in Table 2.

<Example 7>
In the same manner as in Example 3, the first metal layer (nickel) 0.5 μm, the third metal layer (palladium) 0.1 μm, and the second metal layer (Sn-3.0Ag-) are placed on the outside of the acrylic particles in this order from the inside. Particles having 0.5 Cu) 0.5 μm and an outer diameter of 5.2 μm were prepared. Subsequently, the same operation as in (Step d) of Example 1 was performed, and the same copper / nickel / palladium / gold bumps as in Example 6 were used instead of the copper bumps of Example 1 (Step d). .. Subsequently, the same operation as in (Step e) of Example 1 was performed, and instead of heating and pressurizing from above the chip under the conditions of iii) 190 ° C., 40 gf / bump, 10 seconds, 230 ° C., 40 gf / bump, A connection structure was produced in the same manner as in Example 1 (step e) except that the chip was heated and pressurized from above under the condition of 10 seconds. The conductive particles and the connecting structure were evaluated in the same manner as in Example 1. The conditions of the produced conductive particles and the like are summarized in Table 1. The evaluation results are shown in Table 2.

<Example 8>
Similar to Example 4, the first metal layer (nickel) 0.5 μm, the third metal layer (palladium) 0.1 μm, and the second metal layer [Sn-Bi (Sn43% by mass, Bi57% by mass) 0) in this order from the inside. A particle having [5.5 μm] and having an outer diameter of 5.2 μm was prepared. Subsequently, the same operation as in (Step d) of Example 1 was performed, and the same copper / nickel / palladium / gold bumps as in Example 6 were used instead of the copper bumps of Example 1 (Step d). .. After that, the same operation as in Example 1 (step e) was performed to produce a connection structure. The conductive particles and the connecting structure were evaluated in the same manner as in Example 1. 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]
After performing Example 1 (step a), the (step b) of Example 1 was continued, and the liquid volume of electroless nickel plating was set to 100 mL, and the nickel-phosphorus alloy having a film thickness of 0.1 μm shown in Table 1 was used. A first layer composed of a coating (nickel concentration 93% by mass, balance phosphorus) was formed. The particle A obtained by forming the first layer was 2.8 g, and the outer diameter was 3.2 μm. Subsequently, a third metal layer composed 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 is formed on the outside of the acrylic particles in order from the inside. , 3 g of conductive particles having an outer diameter of 3.24 μm on which 0.02 μm of the third metal layer (palladium) was formed were obtained.

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

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

The average particle size of the first insulating particles and the second insulating particles was measured by image analysis of HITACHI S-4800 (manufactured by Hitachi High-Tech Co., Ltd., trade name). The Tg of the first insulating particles and the second insulating particles was measured using a DSC (DSC-7 type manufactured by PerkinElmer) with a sample amount of 10 mg, a heating rate of 5 ° C./min, and a measurement atmosphere: air conditions. did.

(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 the mixture was stirred at 75 ° C. for a certain period of time to obtain a silicone oligomer having a weight average molecular weight of 1300. 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.

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

[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 on the outside of the acrylic particles in this order from the inside, were added to the above reaction solution. In addition, the mixture was stirred at room temperature for 2 hours with a three-one motor and a stirring blade having a diameter of 45 mm. After washing with methanol, the particles were filtered using a membrane filter (manufactured by 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. Conductive particles having a carboxyl group on the surface were added to a 0.3 wt% polyethyleneimine aqueous solution, and the mixture was stirred at room temperature for 15 minutes. Then, the conductive particles were filtered using a membrane filter (manufactured by Millipore) having a pore size of 3 μm, and the filtered conductive particles were placed in 200 g of ultrapure water and stirred at room temperature for 5 minutes. Further, the conductive particles were filtered using a membrane filter having a pore size of 3 μm (manufactured by Millipore), and washed twice with 200 g of ultrapure water on the membrane filter. By performing these operations, unadsorbed polyethyleneimine was removed, and conductive particles whose surface was coated with an amino group-containing polymer were obtained.

Next, the first insulating particles were treated with the silicone oligomer 1 to prepare a methanol dispersion medium for the first insulating particles having a glycidyl group-containing oligomer on the surface. On the other hand, the second insulating particles were also treated with the silicone oligomer 1 in the same manner to prepare a methanol dispersion medium for the second insulating particles having a glycidyl group-containing oligomer on the surface.

The conductive particles whose surface was coated with the amino group-containing polymer were immersed in isopropyl alcohol, and the methanol dispersion medium of the first insulating particles was added dropwise. The coverage of the first insulating particles was adjusted by the amount of the methanol dispersion medium of the first insulating particles added dropwise. Then, the methanol dispersion medium of the second insulating particles was added dropwise to prepare the insulating coated conductive particles 1. 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. Then, it was heated and dried at 80 ° C. for 1 hour to prepare the insulating coated conductive particles 1.

[Preparation of anisotropic conductive adhesive film]
100 g of phenoxy resin (manufactured by Union Carbide, trade name: PKHC) and acrylic rubber (40 parts by weight of butyl acrylate, 30 parts by weight of ethyl acrylate, 30 parts by weight of acrylonitrile) are mixed with 300 g of a solvent obtained by mixing ethyl acetate and toluene at a weight ratio of 1: 1. A solution was obtained by dissolving 75 g of a copolymer of 3 parts by weight of glycidyl methacrylate and a weight average molecular weight of 850,000) by weight. 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 (manufactured by Yuka Shell Epoxy Co., Ltd., product) Name: YL980) 400 g was added and stirred. An adhesive solution 1 was prepared by adding 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 to the obtained mixed solution. The silica slurry was added so that the silica solid content was 5% by weight based on the total solid content of the mixture.

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 insulating coated conductive particles 1 were placed and ultrasonically dispersed. The conditions for ultrasonic dispersion were that the beaker was immersed in an ultrasonic tank (Fujimoto Kagaku, trade name: US107) having a frequency of 38 kHz, an energy of 400 W, and a volume of 20 L, and stirred for 1 minute.

The obtained dispersion liquid of the insulating coating 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 an insulating coating conductive particles per unit area 70,000 pieces / mm ^2. 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 idiosyncratic conductive adhesive film D composed of three layers.

[Preparation of connection sample]
Using the produced anisotropic conductive adhesive film D, copper / nickel / palladium / gold bumps (area 15 μm × 30 μm, space 10 μm, height: 10 μm, number of bumps 362) [electroless electroless Chip with nickel plating (thickness: 0.5 μm), electroless palladium plating (thickness: 0.1 μm), replacement gold plating (thickness: 0.05 μm)] (1.7 × 1.7 mm, thickness: The connection between (0.5 mm) and the glass substrate with IZO circuit (thickness: 0.7 mm) similar to that in Example 1 (step e) was performed as shown below.

After attaching the anisotropic conductive adhesive film D to a glass substrate with an IZO circuit under the conditions of a temperature of 80 ° C. and a pressure of 0.98 MPa (10 kgf / cm2), the separator is peeled off and the copper provided on the chip is provided. Alignment of the glass substrate with / nickel / palladium / gold bumps and electrodes. Next, the main connection was made by heating and pressurizing from above the chip for 10 seconds under the conditions of a temperature of 190 ° C. and a pressure of 39 N / bump (40 gf / bump). The anisotropic conductive adhesive film D was arranged so that the adhesive film B was on the glass substrate side and the adhesive film C was on the metal bump side.

Evaluation of the film thickness and components of the conductive particles, conduction resistance test and insulation resistance test were carried out 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]
After performing steps a and b of Example 1, a third metal layer made of a palladium-plated film having a thickness of 0.1 μm (palladium purity 100%) is formed in the same manner as in Example 3, and further carried out. Similar to Example 4, by forming a second metal layer [Sn-Bi (Sn43% by mass, Bi57% by mass) 0.5 μm] on the third metal layer, the first metal layer is formed on the outside of the acrylic particles in order from the inside. It has a metal layer (nickel) 0.5 μm, a third metal layer (palladium) 0.1 μm, and a second metal layer [Sn-Bi (Sn43% by mass, Bi57% by mass) 0.5 μm], and has an outer diameter of 5. 2 μm conductive particles 2 were produced.
[Preparation 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 conductive particles 2 were placed and ultrasonically dispersed. The conditions for ultrasonic dispersion were that the beaker was immersed in an ultrasonic tank (Fujimoto Kagaku, trade name: US107) having a frequency of 38 kHz, an energy of 400 W, and a volume of 20 L, and stirred for 1 minute.

The obtained dispersion liquid of the 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 prepare an adhesive film F having a thickness of 10 μm. This adhesive film has conductive particles 2 per unit area of 30000 / mm ^2. 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 the order of the adhesive film G, the adhesive film F, and the adhesive film H to prepare an idiosyncratic conductive adhesive film I composed of three layers.

[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) [electroless electroless Chip with nickel plating (thickness: 0.5 μm), electroless palladium plating (thickness: 0.1 μm), replacement gold plating (thickness: 0.05 μm)] (1.7 × 1.7 mm, thickness: The connection between (0.5 mm) and the glass substrate with IZO circuit (thickness: 0.7 mm) similar to that in Example 1 (step e) was performed as shown below.

The anisotropic conductive adhesive film I is attached to a glass substrate with an IZO circuit under the 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 the chip. A glass substrate with copper / nickel / palladium / gold bumps and electrodes was aligned. Next, the main connection was made by heating and pressurizing from above the chip for 10 seconds under the conditions of a temperature of 190 ° C. and a pressure of 39 N / bump (40 gf / bump). The anisotropic conductive adhesive film I was arranged so that the adhesive film G was on the glass substrate side and the adhesive film H was on the metal bump side. Evaluation of the film thickness and components of the conductive particles, conduction resistance test and insulation resistance test were carried out 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.

1 ... Base material particles, 3A, 3B ... Metal layer, 3a ... First metal layer, 3b ... Second metal layer, 3c ... Third metal layer, 10A, 10B ... Conductive particles, 30 ... First circuit member, 32 ... first electrode, 35 ... electrode with terminal, 40 ... second circuit member, 42 ... second electrode, 50A, 50B ... connection structure, 55 ... insulating resin layer, 60 ... transfer type, 60a ... surface, 62 ... Recess (opening), 62a ... Bottom.

Claims (34)

Preparing a first circuit member having a first substrate and a first electrode provided on the first substrate;
Preparing a second circuit member having a second electrode that is electrically connected to the first electrode;
Preparing a plurality of conductive particles having a particle size of 2.0 to 40 μm and having a surface made of metal;
Placing the plurality of conductive particles on the surface of the first electrode;
Fusing the conductive particles 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 metal;
One surface of the first circuit member having the first electrode to which the conductive particles are fused, and one surface of the second circuit member having the second electrode. Forming an insulating resin layer between the surface and the surface;
The first electrode and the second electrode are formed by heating a laminate containing the first circuit member, the insulating resin layer, and the second circuit member in a pressed state in the thickness direction of the laminate. Is electrically connected via the conductive particles and adheres to the first circuit member and the second circuit member;
A method of manufacturing a connection structure including. The conductive particles include base particles and a metal layer formed on the surface of the base particles.
The metal layer has a multilayer structure having at least a first metal layer covering the surface of the base particles and a second metal layer constituting the outermost layer of the conductive particles.
The method for producing a connecting structure according to claim 1, wherein the melting point of the first metal layer is higher than the melting point of the second metal layer. The method for producing a connecting structure according to claim 2, wherein the substrate particles have a particle size of 1.5 to 10 μm. The method for producing a connecting structure according to claim 2 or 3, wherein the base particle is made of a resin. The method for producing a connecting structure according to any one of claims 2 to 4, wherein the first metal layer is a layer containing nickel or a nickel alloy. The method for producing a connecting structure according to claim 5, wherein the first metal layer contains at least one of phosphorus and boron. The method for producing a connecting structure according to claim 5 or 6, wherein the nickel content of the first metal layer is 85 to 98% by mass. The method for producing a connecting structure according to any one of claims 2 to 7, wherein the second metal layer is a layer containing tin or a tin alloy. The method for producing a connecting structure according to claim 8, wherein the tin content of the second metal layer is 30 to 100% by mass. The method for producing a connection structure according to any one of claims 2 to 9, which comprises forming the second metal layer by sputtering or electroplating. The connection structure according to any one of claims 2 to 10, wherein the metal layer includes a third metal layer containing palladium or a palladium alloy between the first metal layer and the second metal layer. Manufacturing method. The method for producing a connecting structure according to claim 11, wherein the palladium content of the third metal layer is 90% by mass or more. The method for producing a connecting structure according to any one of claims 1 to 12, wherein the first electrode is made of copper, nickel, palladium, gold, silver, an alloy thereof, and indium tin oxide. To prepare a transfer mold having a plurality of openings at positions corresponding to the positions where the plurality of conductive particles are arranged on the first electrode;
Accommodating the conductive particles in the plurality of openings;
Including
By superimposing the first circuit member and the transfer mold, the conductive particles housed 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 metal in a state where the first circuit member and the transfer mold are superposed. The method for manufacturing a connecting structure according to any one of claims 1 to 13. The method for manufacturing a connection structure according to claim 14, wherein the opening is formed in a tapered shape in which the opening area expands from the back side of the opening toward the surface side of the transfer mold. The method for producing a connection structure according to claim 14 or 15, wherein the transfer mold is made of a flexible resin material. Preparing a circuit member having a substrate and electrodes provided on the substrate;
Preparing a plurality of conductive particles having a particle size of 2.0 to 40 μm and having a surface made of metal;
Placing the plurality of conductive particles on the surface of the electrode;
To prepare a transfer mold having a plurality of openings in which one of the conductive particles is housed at a position corresponding to the position of the plurality of conductive particles on the electrode;
Accommodating the conductive particles in the plurality of openings;
By superimposing the circuit member and the transfer mold, the conductive particles housed 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 metal in a state where the circuit member and the transfer mold are overlapped with each other, whereby the conductive particles are fused to the electrode. Fusing particles;
A method for manufacturing an electrode with a terminal, including. The conductive particles include base particles and a metal layer formed on the surface of the base particles.
The metal layer has a multilayer structure having at least a first metal layer covering the surface of the base particles and a second metal layer constituting the outermost layer of the conductive particles.
The method for manufacturing an electrode with a terminal according to claim 17, wherein the melting point of the first metal layer is higher than the melting point of the second metal layer. The method for manufacturing an electrode with a terminal according to claim 18, wherein the substrate particles have a particle size of 1.5 to 10 μm. The method for producing an electrode with a terminal according to claim 18 or 19, wherein the base particle is made of a resin. The method for manufacturing an electrode with a terminal according to any one of claims 18 to 20, wherein the first metal layer is a layer containing nickel or a nickel alloy. The method for manufacturing an electrode with a terminal according to claim 21, wherein the first metal layer contains at least one of phosphorus and boron. The method for manufacturing an electrode with a terminal according to claim 21 or 22, wherein the nickel content of the first metal layer is 85 to 98% by mass. The method for manufacturing an electrode with a terminal according to any one of claims 18 to 23, wherein the second metal layer is a layer containing tin or a tin alloy. The method for manufacturing an electrode with a terminal according to claim 24, wherein the tin content of the second metal layer is 30 to 100% by mass. The method for manufacturing an electrode with a terminal according to any one of claims 18 to 25, which comprises forming the second metal layer by sputtering or electroplating. The terminalized electrode according to any one of claims 18 to 26, wherein the metal layer includes a third metal layer containing a palladium or a palladium alloy between the first metal layer and the second metal layer. Manufacturing method. The method for manufacturing an electrode with a terminal according to claim 27, wherein the palladium content of the third metal layer is 90% by mass or more. The method for manufacturing an electrode with a terminal according to any one of claims 17 to 28, wherein the electrode is made of copper, nickel, palladium, gold, silver, an alloy thereof, and indium tin oxide. The terminalized electrode according to any one of claims 17 to 29, wherein the opening is formed in a tapered shape in which the opening area expands from the back side of the opening toward the surface side of the transfer mold. Production method. The method for manufacturing an electrode with a terminal according to any one of claims 17 to 30, wherein the transfer type is made of a flexible resin material. A plurality of conductive particles each having a surface made of a metal having a particle size of 2.0 to 40 μm and a melting point of 120 to 250 ° C.
A transfer type having a plurality of openings in which one of the conductive particles is housed at a position corresponding to a position on the surface of the electrode where the plurality of the conductive particles are arranged.
Kit for manufacturing electrodes with terminals. The kit for manufacturing an electrode with a terminal according to claim 32 , wherein the opening is formed in a tapered shape in which the opening area expands from the back side of the opening toward the surface side of the transfer mold. The kit for manufacturing an electrode with a terminal according to claim 32 or 33 , wherein the transfer type is made of a flexible resin material.

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