JP6897038B2 - 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 driving 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. Further, even when 70,000 pieces / mm ² or more conductive particles are charged per unit area, insulation-coated conductive particles having excellent insulation reliability have been proposed. In Patent Document 3, the first insulating particles are used. , 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.
-Place the above-mentioned plurality of conductive particles on the surface of the first electrode.
-Forming a plating layer that covers the first electrode and a plurality of conductive particles arranged on the surface of the first electrode.
One surface of the first circuit member having the first electrode covered with the conductive particles by the plating layer, and one surface of the second circuit member having the second electrode. To form an insulating resin layer between the surface and the surface.
-The first electrode and the second electrode are electrically heated by heating the laminate including the first circuit member, the insulating resin layer, and the second circuit member in a pressed state in the thickness direction of the laminate. And adhere to the first circuit member and the second circuit member.

According to the method for manufacturing the connection structure, the first electrode and the first electrode to be electrically connected to each other are fixed by covering the surface of the first electrode with a plurality of conductive particles with a plating layer. Conductive particles can be sufficiently stably arranged between the two electrodes. 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 covered with the plating layer on the surface of the first electrode act as bumps (connecting protrusions), so that innumerable conductive particles contained in the anisotropic conductive material 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 for which the insulating property should be ensured.

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.
-Place the above-mentioned plurality of conductive particles on the surface of the electrode.
-Forming a plating layer that covers the electrode and a plurality of conductive particles arranged on the surface of the electrode.

According to the above-mentioned method for manufacturing an electrode with terminals, conductive particles covered with a plating layer on the surface of the electrode can serve as 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 in a state where the circuit member (first circuit member) and the transfer mold are overlapped with each other, the electrode (first electrode) and the electrode (first electrode) A plating layer may be formed to cover a plurality of conductive particles arranged on the surface of the electrode).

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 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 conductivity larger than the size of the recess. The particles are not contained in the recess. 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.

The present invention provides a connection structure. That is, the connection structure according to the present invention has a first substrate and a first circuit member having a first electrode provided on the first substrate; and is electrically connected to the first electrode. A second circuit member having the second electrode, the conductive particles interposed between the first electrode and the second electrode, and a plating layer covering the first electrode and the plurality of conductive particles. An insulating resin layer provided between the first circuit 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 covered with the plating layer on the surface of the electrode play the role of bumps (projections for connection), 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 is a transfer type having a plurality of openings at positions corresponding to the above-mentioned conductive particles, one or more kinds of electrolytic plating solutions, and a plurality of conductive particles arranged on the electrode surface. And. According to this kit, a plurality of fine conductive particles (particle size 2.0 to 40 μm) can be sufficiently stably fixed at predetermined positions on the electrode surface by the plating layer.

In the present invention, the conductive particles preferably include base particles and a metal layer formed on the surface of the base particles. 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.

The metal layer may have a single-layer structure or a multi-layer structure as long as sufficiently high conductivity can be ensured. The metal layer preferably contains at least a first metal layer containing nickel or a nickel alloy. 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 a layer containing nickel or a nickel alloy is adopted as the first metal layer, the first metal layer may contain at least one of phosphorus and boron. Phosphorus and / or boron contained in the first metal layer suppresses the diffusion of elements from other layers constituting the metal layer into the first metal layer, for example, when the metal layer has a multi-layer structure. As a result, the reliability of the conductive particles can be kept good.

Examples of the material constituting the electrode (first electrode) of the circuit member (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 an electrode with a terminal formed by covering the conductive particles shown in FIG. 1 with a plating layer. FIG. 3 is a cross-sectional view schematically showing an electrode with a terminal formed by further covering the plating layer shown in FIG. 1 with a second plating layer. FIG. 4 is an enlarged view showing a part of the connection structure according to the present invention, and is a schematic example of a state in which the first electrode and the second electrode are electrically connected by conductive particles and a plating layer. It is a cross-sectional view which shows. FIG. 5 is a cross-sectional view schematically showing an embodiment of the connection structure according to the present invention. 6 (a) to 6 (c) are cross-sectional views schematically showing an example of a part (first half) of the process of forming an electrode with a terminal on the first circuit member. 7 (a) and 7 (b) are cross-sectional views schematically showing an example of a part (second half) of the 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. Is. 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 (a) is formed and a second circuit member. It is sectional drawing which shows typically. FIG. 12 is a plan view schematically showing a circuit member in which a total of eight conductive particles are fused to each electrode. FIG. 13 is a plan view schematically showing a circuit member in which a total of four conductive particles are fused to each electrode.

Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments. 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 10 shown in FIG. 1 are spherical particles including the base particles 1 and the metal layer 3 having a two-layer structure formed on the surface of the base particles 1. The conductive particles 10 are fixed to the surface of the electrode 32 by an electrolytic plating layer (plating layer) 5 prior to circuit connection (see FIG. 2). 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 10 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 10 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 10 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 an 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 the reflow connection is performed by soldering, 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 10 exhibits excellent dimensional stability, which tends to obtain good connection reliability and insulation reliability.

[Metal layer]
As shown in FIG. 1, the metal layer 3 has a single-layer structure and covers the base particles 1. The metal layer 3 is composed of, for example, a layer containing nickel or a nickel alloy. The metal layer 3 may have a multi-layer structure including a plurality of metal layers, if necessary. The metal layer 3 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.

The nickel content of the metal layer 3 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 metal layer 3 remains stably after the second electrode 42 and the conductive particles 10 described later are electrically bonded (see FIG. 4), which is high. There is a tendency to maintain connection reliability.

The thickness of the metal layer 3 is, for example, 0.05 μm or more, and may be in the range of 0.05 to 5 μm, 0.1 to 3 μm, or 0.2 to 2 μm. When the thickness of the metal layer 3 is 0.05 μm or more, the metal layer 3 remains stable after the second electrode 42 and the conductive particles 10 are electrically bonded (see FIG. 4), which is high. There is a tendency to maintain connection reliability. If the thickness of the metal layer 3 is less than 0.05 μm, the adhesion between the base particle 1 and the metal layer 3 is insufficient after the second electrode 42 and the conductive particles 10 are electrically bonded. This tends to reduce the connection reliability.

The metal layer 3 may contain at least one of phosphorus and boron, and may particularly contain phosphorus. When the metal layer 3 contains these elements, the hardness of the metal layer 3 is improved after the second electrode 42 and the conductive particles 10 are electrically bonded, thereby increasing the connection resistance value with the circuit electrode. It can be low enough.

The metal layer 3 can be formed by electroless nickel plating. The metal layer 3 may be formed by electroless nickel plating by a known method. For example, the surface of the base particle 1 may be palladium-catalyzed and then electroless nickel plating may be performed. 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. 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 metal layer 3 containing the alloy) can be formed.

<Electrode with terminal>
FIG. 2 is a cross-sectional 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 10 arranged on the surface of the electrode 32 of the first circuit member 30 are covered with the electrolytic plating layer 5. The conductive particles 10 fixed by the electrolytic plating layer 5 serve as bumps (connecting protrusions) on the surface of the electrode 32. The electrolytic plating layer 5 is composed of, for example, an electrolytic nickel plating layer or an electrolytic palladium plating layer. The first circuit member 30 includes a first circuit board 31 and a first electrode 32 arranged on the surface 31a thereof.

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.

When the electrolytic plating layer 5 is composed of an electrolytic nickel plating layer, the nickel content thereof 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 electrolytic plating layer 5 remains stably after the second electrode 42 described later and the electrolytic plating layer 5 are electrically bonded (see FIG. 4). As a result, high connection reliability tends to be maintained. When the electrolytic plating layer 5 is made of an electrolytic nickel plating layer, its thickness is, for example, 0.05 μm or more, and may be in the range of 0.05 to 5 μm, 0.1 to 3 μm, or 0.2 to 2 μm. When the thickness of the electrolytic plating layer 5 is 0.05 μm or more, after the second electrode 42 and the electrolytic plating layer 5 are electrically bonded (see FIG. 4), the electrolytic plating layer 5 remains stably. As a result, high connection reliability tends to be maintained.

When the electrolytic plating layer 5 is composed of an electrolytic palladium plating layer, the palladium content thereof is, for example, 85 to 98% by mass, and may be 87 to 96% by mass or 90 to 95% by mass. When the palladium content is 85 to 98% by mass, the electrolytic plating layer 5 remains stably after the second electrode 42 described later and the electrolytic plating layer 5 are electrically bonded (see FIG. 4). It tends to maintain higher connection reliability. When the electrolytic plating layer 5 is made of an electrolytic palladium plating layer, its thickness is, for example, 0.05 μm or more, even if it is in the range of 0.05 to 5 μm, 0.1 to 3 μm, or 0.2 to 2 μm. Good. When the thickness of the electrolytic plating layer 5 is 0.05 μm or more, after the second electrode 42 and the electrolytic plating layer 5 are electrically bonded (see FIG. 4), the electrolytic plating layer 5 remains stably. As a result, high connection reliability tends to be maintained.

FIG. 3 is a cross-sectional view schematically showing a modified example of the electrode 35 with a terminal shown in FIG. The terminal-attached electrode 36 shown in the figure is different from the terminal-attached electrode 35 in that the electrolytic plating layer 5 is covered with a coating layer (second plating layer) 6 formed by plating. For example, the electrolytic plating layer 5 may be composed of the electrolytic nickel plating layer and the coating layer 6 may be composed of the electroless palladium plating layer or the electrolytic palladium plating layer, or vice versa. Further, the electrolytic plating layer 5 may be composed of a plurality of electrolytic nickel plating layers, or may be composed of a plurality of palladium plating layers. Since palladium is difficult to diffuse, has the effect of suppressing the diffusion of nickel, and can be expected to have the effect of improving insulation reliability, the electrolytic nickel plating layer and the electroless palladium plating layer are arranged in this order from the base particle 1 side. It is preferable that they are lined up in a row.

<Connection structure>
FIG. 4 is an enlarged sectional view schematically showing a part of the connection structure 50 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 10 and the electrolytic plating layer 5. Is. The second circuit member 40 includes a second circuit board 41 and a second electrode 42 arranged on the surface 41a thereof. Although the terminal-equipped electrode 35 is used here, the terminal-equipped electrode 36 may be used instead.

As shown in FIG. 4, the connection structure 50 includes conductive particles 10 interposed between the first circuit member 30, the second circuit member 40, and the first electrode 32 and the second electrode 42. And an electrolytic plating layer 5 that covers the conductive particles 10, 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.

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 50 shown in FIG. 5 includes a plurality of connection portions formed by the conductive particles 10 and the electrolytic plating layer 5 shown in FIG. 4 (three are shown in FIG. 5). Since the electrical connection between the electrodes 32 and 42 facing each other is secured by the conductive particles 10 and the electrolytic plating layer 5, it is not necessary to use an anisotropic conductive adhesive. In other words, the insulating resin layer 55 is Those that do not contain conductive particles may be adopted. 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 structure 50 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. 6 to 10. Here, a method of manufacturing the electrode 35 with terminals by arranging a plurality of conductive particles 10 on the surface of the electrode 32 included in the first circuit member 30 and forming an electrolytic plating layer 5 so as to cover them will be described. 6 (a) to 6 (c) and 7 (a) and 7 (b) are cross-sectional views schematically showing examples of the first half and the second half of the process of forming an electrode with a terminal on the first circuit member, respectively.

(Preparation of transfer type)
First, a transfer mold 60 for arranging a plurality of conductive particles 10 on the surface of the electrode 32 and forming the electrolytic plating layer 5 while maintaining the state 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 10 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 10 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 10 to be arranged on the surface of the electrode 32. That is, when the conductive particles 10 to be arranged on the surface of the electrode 32 are housed in the recess 62, the height of the conductive particles 10 protruding from the recess 62 (the distance from the surface 60a of the transfer mold 60 to the upper end of the conductive particles 10 (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 10 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 10 in the recess 62 in a state of being accommodated, 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. As described above, since the transfer mold 60 is immersed in the electrolytic plating solution together with the first circuit member 30, it is preferably made of a material having chemical resistance and heat resistance.

By using the transfer type 60, even if the particle size distribution of the conductive particles 10 has a certain width, a plurality of conductive particles 10 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 10 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 is turned downward, while the size of the recess 62 is larger than the size of the recess 62. The large conductive particles 10 are not housed in the recess 62. Conductive particles 10 that match 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 10 are brought into contact with the electrode surface. The conductive particles 10 can be arranged according to the formation pattern of the recesses 62 (see FIGS. 6A and 6B). Although the recess 62 (bottomed opening) is illustrated here as the opening in which the conductive particles 10 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. 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 of conductive particles and formation of plating layer)
FIG. 6A is a cross-sectional view schematically showing a state in which the transfer mold 60 containing the conductive particles 10 in each recess 62 faces the surface of the first circuit member 30. FIG. 6B is a cross-sectional view schematically showing a state in which the conductive particles 10 housed in the recess 62 of the transfer mold 60 are brought into contact with the surface of the first electrode 32. By performing the electrolytic plating treatment (for example, electrolytic nickel plating treatment or electrolytic palladium plating treatment) while maintaining the state shown in FIG. 6B, the electrolytic plating layer 5 covering the first electrode 32 and the conductive particles 10 is formed. Form. FIG. 6C is a cross-sectional view schematically showing a state in which the electrolytic plating layer 5a is formed on the lower side (first electrode 32 side) of the conductive particles 10. When the conductive particles 10 are fixed to the first electrode 32 by forming the electrolytic plating layer 5a, the transfer mold 60 is removed from the surface of the electrode 32, and the electrolytic plating process is continued. As a result, as shown in FIG. 7A, the electrolytic plating layer 5 is formed so as to cover the first electrode 32 and the conductive particles 10 arranged on the first electrode 32. By further forming a coating layer 6 (for example, an electroless palladium plating layer) on the surface of the electrolytic plating layer 5 of the terminal electrode 35 thus obtained, the terminal electrode 36 having the configuration shown in FIG. 7B can be obtained. can get.

The electrolytic plating layer 5 can be formed by immersing the laminate (transfer mold 60 containing conductive particles and the first circuit member 30) shown in FIG. 6B, for example, in an electrolytic nickel plating solution. The electrolytic nickel plating solution includes a watt bath (nickel plating bath containing nickel sulfate, nickel chloride, and boric acid as main components), a sulfamic acid bath (nickel plating bath containing nickel sulfamate and boric acid as main components), and boric acid. A bath or the like can be used. Among them, the precipitated film from the watt bath tends to have good adhesion to the conductive particles 10 as a base material and the first electrode 32, and can have high corrosion resistance. Therefore, it is preferable to use a watt bath for electrolytic nickel plating.

The thickness of the electrolytic nickel plating layer (electroplating layer 5) formed by electrolytic nickel plating is preferably 0.05 to 5 μm, more preferably 0.1 to 3 μm, and 0.2 to 1 μm. Is even more preferable. By setting this thickness to 0.05 μm or more, good connection with the conductive particles 10 and the first electrode 32 can be obtained. However, even if it exceeds 5 μm, these effects are not significantly improved and it is not economical. Therefore, the upper limit of the thickness of the electrolytic nickel plating layer may be 5 μm.

A coating layer 6 (second plating layer) made of palladium or a palladium alloy may be formed on the outer surface (opposite side of the first electrode 32) of the electrolytic nickel plating layer (electroplating layer 5). The coating layer 6 may be an electrolytic palladium plating layer or an electroless palladium plating layer, but it is preferable to form the coating layer 6 by electroless palladium plating because it does not require uniformity of thickness and electricity.

As electroless palladium plating, substituted palladium plating and reduced palladium plating using a reducing agent can be applied. As a method for forming the palladium layer by electroless palladium plating, a method of performing reduced palladium plating after performing substituted palladium plating is particularly preferable. This is because the electroless palladium plating reaction tends to be difficult to occur on the coating layer 6 formed by electrolytic nickel plating as it is. A palladium layer can be satisfactorily formed by preliminarily precipitating palladium by substitution palladium plating and then precipitating the palladium layer by reduced palladium plating.

The thickness of the palladium layer is preferably 0.003 to 0.5 μm, more preferably 0.01 to 0.3 μm, and even more preferably 0.03 to 0.2 μm. When the thickness of the palladium layer exceeds 0.5 μm, the effect of forming the palladium layer is not further improved, and it tends to be uneconomical. On the other hand, if it is thinner than 0.03 μm, a portion where the palladium layer is not precipitated is likely to be included, and the effect of improving the insulation reliability by forming the palladium layer may not be sufficiently obtained.

The source of palladium in the plating solution used for electroless palladium plating is not particularly limited, and examples thereof include palladium compounds such as palladium chloride, sodium palladium chloride, ammonium palladium chloride, palladium sulfate, palladium nitrate, palladium acetate, and palladium oxide. Be done. Specifically, acidic palladium chloride "PdCl2 / HCl", tetraammine palladium sulfate "Pd (NH ₃ ) ₄ NO ₂ ", palladium sodium nitrate salt "Pd (NO ₃ ) ₂ / H ₂ SO ₄ ", dinitrodiammine palladium " Pd (NH ₃ ) ₂ (NO ₂ ) ₂ ”, dicyanodiammine palladium“ Pd (CN) ₂ (NH ₃ ) ₂ ”, dichlorotetraammine palladium“ Pd (NH ₃ ) ₄ Cl ₂ ”, palladium sulfamate“ Pd (NH 3) 2 ” ₂ SO _{3) 2} ', sulfate diammine palladium "Pd _{(NH 3)} 2 SO _4", oxalate tetraamminepalladium _{"Pd (NH 3) 4 C 2} O 4 ", is possible to apply the palladium sulfate "PdSO _4", etc. it can. Further, the buffering agent or the like added to the plating solution is not particularly limited.

The palladium layer formed by electroless palladium plating preferably has a palladium purity of 90% by mass or more, more preferably 99% by mass or more, and particularly preferably close to 100% by mass. If the purity of palladium is less than 90% by mass, precipitation on the electrolytic nickel plating 5 is unlikely to occur during its formation, and the effect of improving insulation reliability by forming the palladium layer may not be sufficiently obtained. ..

When a formic acid compound is used as the reducing agent used for electroless palladium plating, the purity of the obtained palladium layer (coating layer) tends to be 99% by mass or more, and uniform precipitation becomes possible. Further, when a phosphorus-containing compound such as hypophosphorous acid or phosphorous acid or a boron-containing compound is used as the reducing agent, the obtained palladium layer becomes a palladium-phosphorus alloy and / or a palladium-boron alloy. It is preferable to adjust the concentration, pH, bath temperature, etc. of the reducing agent so that the purity of palladium is 90% by mass or more.

Further, the palladium layer does not necessarily have to be formed by electroless palladium plating, and may be formed by electrolytic palladium plating. In that case, the source of palladium in the electrolytic palladium plating solution used for electrolytic palladium is not particularly limited, and palladium compounds such as palladium chloride, sodium palladium chloride, ammonium palladium chloride, palladium sulfate, palladium nitrate, palladium acetate, and palladium oxide are used. Can be applied. Specifically, acidic palladium chloride (PdCl ₂ / HCl), tetraammine palladium sulfate (Pd (NH ₃ ) ₄ NO ₂ ), sodium palladium nitrate (Pd (NO ₃ ) ₂ / H ₂ SO ₄ ), dinitrodiammine palladium. (Pd (NH ₃ ) ₂ (NO ₂ ) ₂ ), dicyanodiammine palladium (Pd (CN) ₂ (NH ₃ ) ₂ ), dichlorotetraammine palladium (Pd (NH ₃ ) ₄ Cl ₂ ), palladium sulfamate (Pd (NH 3) 4 Cl 2) Examples thereof include NH ₂ SO ₃ ) ₂ ), diammine palladium sulfate (Pd (NH ₃ ) ₂ SO ₄ ), tetraammine palladium oxalate (Pd (NH ₃ ) ₄ C ₂ O ₄ ), and palladium sulfate (PdSO _4). Further, the buffering agent and the like contained in the electrolytic palladium plating solution are not particularly limited, and those contained in known electrolytic palladium plating solutions can be applied.

<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 a process of forming a connection structure including the first circuit member 30 on which the terminal-attached electrode 35 shown in FIG. 7A 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. 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.

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 2 g of crosslinked polystyrene particles (manufactured by Nippon Catalyst Co., Ltd., trade name "Soliostar") with an average particle size of 3.0 μm are added to Atotech Neogant 834 (manufactured by Atotech Japan Co., Ltd.) 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, a non-electrolytic nickel plating solution for forming a metal layer having the following composition (an aqueous solution containing the following components. 1 mL of a 1 g / L bismuth nitrate aqueous solution was added per 1 L of the plating solution. The same applies hereinafter) to a dispersion liquid containing 2 g of resin particles. 500 mL 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 metal layer made of a nickel-phosphorus alloy (nickel concentration 93% by mass, balance phosphorus) having a thickness of 0.5 μm shown in Table 1 was formed. The particle A obtained by forming the metal layer was 6 g, and the outer diameter was 4 μm.
(Electroless nickel plating solution for metal layer formation)
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

[Manufacturing electrodes with terminals]
(Step c)
Conductive particles (outer diameter 4 μm) obtained through step b are placed at the center of the opening diameter 5 μm square, bottom diameter 3 μm square, and depth 4 μm (bottom diameter 3 μm square is the center of the opening diameter 5 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 conductive particles were brought into contact with each other. The laminate in this state was immersed in an electrolytic nickel plating solution having the following composition, and then electrolytic nickel plating was performed to connect the copper bumps and the conductive particles. The electrolytic nickel plating is performed under the conditions of a liquid temperature of 55 ° C. and a current density of 1.0 A / dm ² for 2 minutes in a state where the copper bumps and the conductive particles are in contact with each other. The electrolytic plating layer having a thickness of 0.5 μm was formed.
(Electrolytic nickel plating solution)
Nickel sulfate: 240 g / L
Nickel chloride: 45 g / L
Boric acid: 30 g / L
Surfactant: 3 ml / L
pH: 4
(Manufactured by Japan High Purity Chemical Co., Ltd., Product name: Pit inhibitor # 62)

As shown in FIG. 12, 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. 13 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 copper bumps: 4 ・ Chip C3: Area 15 μm × 30 μm, space 6 μm, height: 10 μm, number of bumps 362, number of conductive particles on copper bumps 8

[Preparation of connection structure]
(Step d)
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 metal layer 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 images, the thickness of the metal layer in the radial direction from the center of the conductive particles was measured. Five conductive particles were measured at five points each, and the average value of a total of 25 points was taken as the thickness of the metal layer. In addition, the content (purity) of the element in the metal layer 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: percentage of higher insulation resistance 10 ⁹ Omega 100%
B: Insulation resistance value 10 ⁹ Ω or more is 90% or more and less than 100% C: Insulation resistance value 10 ⁹ Ω or more is 80% or more and less than 90% D: Insulation resistance value 10 ⁹ Ω or more is 50% or more and less than 80% E: ratio of more than the insulation resistance 10 ⁹ Omega is less than 50%

<Example 2>
Conductive in the same manner as in Example 1 except that an electroless nickel plating layer was formed on the copper bumps and conductive particles and then an electroless palladium plating layer was further formed on the surface of the copper bump and the conductive particles in (step d) of Example 1. Particles, electrodes with terminals, connection structures were prepared, and conductive particles and connection structures were evaluated. The conditions of the produced conductive particles and the like are summarized in Table 1. The evaluation results are shown in Table 2. The electroless palladium plating was carried out under the conditions of an immersion time of 3 minutes and a temperature of 60 ° C., and an electroless palladium plating having a thickness of 0.03 μm was formed on the surface of the electrolytic nickel plating layer.
(Electroless palladium plating solution)
Palladium chloride ... 0.07 g / L
Ethylenediamine: 0.05 g / L
Sodium formate ... 0.2 g / L
Tartaric acid ・ ・ ・ ・ ・ ・ ・ ・ 0.11g / L
pH ・ ・ ・ ・ ・ ・ ・ ・ ・ 7

<Example 3>
Conductive particles and bumps were formed in the same manner as in Example 2 except that the immersion time in the electroless palladium plating solution in Example 2 was set to 5 minutes and the thickness of the electroless palladium plating layer was set to 0.05 μm. The connection terminals were manufactured, the connection structure was manufactured, and the conductive particles and the connection structure were evaluated. The conditions of the produced conductive particles and the like are summarized in Table 1. The evaluation results are shown in Table 2.

<Example 4>
Conductive particles and bumps were formed in the same manner as in Example 2 except that the immersion time in the electroless palladium plating solution in Example 2 was 10 minutes and the thickness of the electroless palladium plating layer was 0.1 μm. The connection terminals were manufactured, the connection structure was manufactured, and the conductive particles and the connection structure were evaluated. 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 step (step c) of Example 1, instead of forming the electrolytic nickel plating layer, Parabright SST-L (Japan High Purity Chemical Co., Ltd., trade name), which is an electrolytic palladium plating solution, is used at 60 ° C. Electrolytic palladium plating was performed at 1 A / dm ² for 20 seconds to precipitate a palladium plating layer having a thickness of 0.1 μm. Other than that, conductive particles, bump-shaped connection terminals, connection structures were produced, and conductive particles and connection structures 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 step (step c) of Example 1, instead of forming the electrolytic nickel plating layer, Parabright SST-L (Japan High Purity Chemical Co., Ltd., trade name), which is an electrolytic palladium plating solution, is used at 60 ° C. Electrolytic palladium plating was performed at 1 A / dm ² for 1 minute to precipitate a palladium layer having a thickness of 0.3 μm. Other than that, conductive particles, bump-shaped connection terminals, connection structures were produced, and conductive particles and connection structures 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 step (step c) of Example 1, instead of forming the electrolytic nickel plating layer, Parabright SST-L (Japan High Purity Chemical Co., Ltd., trade name), which is an electrolytic palladium plating solution, is used at 60 ° C. Electrolytic palladium plating was performed at 1 A / dm ² for 1 minute and 40 seconds to precipitate a palladium plating layer having a thickness of 0.5 μm. Other than that, conductive particles, bump-shaped connection terminals, connection structures were produced, and conductive particles and connection structures 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>
After performing the steps (step a) to (step c) in Example 1, an electrolytic palladium plating solution is applied to the bump-shaped connecting terminal surface on which an electrolytic nickel plating layer is formed on copper bumps and conductive particles. ^{Electrolytic palladium plating was performed at 60 ° C. and 1 A / dm 2} for 20 seconds using Parabrite SST-L (Japan High Purity Chemical Co., Ltd., trade name) to precipitate a palladium plating layer having a thickness of 0.1 μm. It was. After that, in the same manner as in (Step d) and subsequent steps in Example 1, the conductive particles and bump-shaped connecting terminals were manufactured, the connecting structure was manufactured, and the conductive particles and the connecting structure were evaluated. The conditions of the produced conductive particles and the like are summarized in Table 1. The evaluation results are shown in Table 2.

<Example 9>
After performing the steps (step a) to (step c) in Example 1, an electrolytic palladium plating solution is applied to the bump-shaped connecting terminal surface on which an electrolytic nickel plating layer is formed on copper bumps and conductive particles. ^{Electrolytic palladium plating was performed at 60 ° C. and 1 A / dm 2} for 1 minute using Parabrite SST-L (Japan High Purity Chemical Co., Ltd., trade name) to precipitate a palladium plating layer having a thickness of 0.3 μm. It was. After that, in the same manner as in (Step d) and subsequent steps in Example 1, the conductive particles and bump-shaped connecting terminals were manufactured, the connecting structure was manufactured, and the conductive particles and the connecting structure were evaluated. The conditions of the produced conductive particles and the like are summarized in Table 1. The evaluation results are shown in Table 2.

<Example 10>
After performing the steps (step a) to (step c) in Example 1, an electrolytic palladium plating solution is applied to the bump-shaped connecting terminal surface on which an electrolytic nickel plating layer is formed on copper bumps and conductive particles. ^{Electrolytic palladium plating was performed at 60 ° C. and 1 A / dm 2} for 1 minute and 40 seconds using Parabrite SST-L (Nippon High Purity Chemical Co., Ltd., trade name) to form a palladium plating layer with a thickness of 0.5 μm. It was precipitated. After that, in the same manner as in (Step d) and subsequent steps in Example 1, the conductive particles and bump-shaped connecting terminals were manufactured, the connecting structure was manufactured, and the conductive particles and the connecting structure were evaluated. 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>
In the step (step c) of Example 1, instead of forming the electrolytic nickel plating layer, a copper sulfate bath was used, and the electrolytic copper was used for 2 minutes under the conditions of a ^{liquid temperature of 25 ° C. and a current density of 1.0 A / dm 2.} Plating was performed to precipitate a copper plating layer having a thickness of 0.5 μm. Other than that, conductive particles, bump-shaped connection terminals, connection structures were produced, and conductive particles and connection structures were evaluated in the same manner as in Example 1. The conditions of the produced conductive particles and the like are summarized in Table 3. The evaluation results are shown in Table 4.

<Comparative example 2>
[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 thickness of 0.1 μm shown in Table 5 was used. A first layer composed of nickel concentration 93% by mass and 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. 2.8 g of the particles forming the first metal layer (nickel) was diluted with 200 mL of water heated at 50 ° C., and 0.2 mL of a 1 g / L bismuth nitrate aqueous solution was added as a plating stabilizer to obtain the following composition. 20 mL of the electroless palladium plating solution for forming the second metal layer 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 layer made of palladium plating (palladium purity 100%) having a thickness of 0.02 μm shown in Table 5 was formed. In addition, 3 g of conductive particles having an outer diameter of 3.24 μm, in which a first metal layer (nickel) 0.1 μm and a second metal layer (palladium) 0.02 μm were formed on the outside of the acrylic particles in order from the inside, were obtained. It was.
(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

[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)
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 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 mass.

The weight average molecular weight of the silicone oligomer was measured by a gel permeation chromatography (GPC) method and calculated by converting 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 (all 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% by mass polyethyleneimine aqueous solution. Conductive particles having a carboxyl group on the surface were added to a 0.3 mass% 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 a silicone oligomer 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 a silicone oligomer 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. 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 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 insulating coated conductive particles.

[Preparation of anisotropic conductive adhesive film]
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) are mixed with 300 g of a solvent obtained by mixing ethyl acetate and toluene at a mass ratio of 1: 1. A solution was obtained by dissolving 75 g of a copolymer having 3 parts by mass and 3 parts by mass of glycidyl methacrylate and a weight average molecular weight of 850,000). 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 mass with respect to 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 mass ratio of 1: 1 and insulating coated conductive particles 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 of insulating coated conductive particles 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 anisotropic 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.

The anisotropic conductive adhesive film D 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 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 thickness and composition of the metal layer of the conductive particles, conduction resistance test and insulation resistance test were carried out in the same manner as in Example 1. Table 5 shows the conditions of the produced conductive particles and the like. The evaluation results are shown in Table 4.

1 ... Base particle, 3 ... Metal layer, 5 ... Electroplating layer (plating layer), 6 ... Coating layer (second plating layer), 10 ... Conductive particles, 30 ... First circuit member, 32 ... First Electrodes, 35, 36 ... Electrodes with terminals, 40 ... Second circuit members, 42 ... Second electrodes, 50 ... Connection structures, 55 ... Insulating resin layers, 60 ... Transfer type, 60a ... Surfaces, 62 ... Recesses (Opening), 62a ... Bottom.

Claims (33)

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;
Placing the plurality of conductive particles on the surface of the first electrode;
Forming an electroplating layer that covers the first electrode and the plurality of conductive particles arranged on the surface of the first electrode;
One surface of the first circuit member having the first electrode covered with the conductive particles and the electrolytic plating layer, and one surface of the second circuit member. Forming an insulating resin layer with the surface having the second electrode;
The first electrode and the second electrode are formed by heating a laminate including the first circuit member, the insulating resin layer, and the second circuit member in a pressed state in the thickness direction of the laminate. To electrically connect and bond the first circuit member to the second circuit member;
A method of manufacturing a connection structure including. The method for producing a connecting structure according to claim 1, wherein the conductive particles include base particles and a metal layer having a single-layer structure or a multi-layer structure formed on the surface of the base particles. 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 metal layer includes at least a first metal layer containing nickel or a nickel alloy formed by electroless plating. 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 manufacturing a connection structure according to any one of claims 1 to 7, wherein the electrolytic plating layer is an electrolytic nickel plating layer or an electrolytic palladium plating layer. The method for manufacturing a connection structure according to any one of claims 1 to 8, further comprising forming an electroless plating layer that covers the surface of the electroplating layer. The method for manufacturing a connection structure according to claim 9, wherein the electroless plating layer is an electroless nickel plating layer or an electroless palladium plating layer. The method for producing a connecting structure according to any one of claims 1 to 10, wherein the first electrode is made of copper, nickel, palladium, gold, silver, an alloy thereof, and indium tin oxide. 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.
In a state where the first circuit member and the transfer mold are overlapped with each other, an electroplating layer covering the first electrode and the plurality of conductive particles arranged on the surface of the first electrode is formed. The method for manufacturing a connecting structure according to any one of claims 1 to 11. The method for manufacturing a connection structure according to claim 12, 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 connecting structure according to claim 12 or 13, wherein the transfer type 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;
Placing the plurality of conductive particles on the surface of the electrode;
Forming an electrolytic plating layer covering the plurality of conductive particles disposed in front Symbol electrodes and the surface of the front Symbol electrodes;
A method for manufacturing an electrode with a terminal including. The method for manufacturing an electrode with a terminal according to claim 15, wherein the conductive particles include base particles and a metal layer having a single-layer structure or a multi-layer structure formed on the surface of the base particles. The method for manufacturing an electrode with a terminal according to claim 16, 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 16 or 17, wherein the base particle is made of a resin. The method for manufacturing an electrode with a terminal according to any one of claims 16 to 18, wherein the metal layer includes at least a first metal layer containing nickel or a nickel alloy formed by electroless plating. The method for manufacturing an electrode with a terminal according to claim 19, 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 19 or 20, 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 15 to 21, wherein the electrolytic plating layer is an electrolytic nickel plating layer or an electrolytic palladium plating layer. The method for manufacturing an electrode with a terminal according to any one of claims 15 to 22, further comprising forming an electroless plating layer covering the surface of the electroplating layer. The method for manufacturing an electrode with a terminal according to claim 23, wherein the electroless plating layer is an electroless nickel plating layer or an electroless palladium plating layer. The method for manufacturing an electrode with a terminal according to any one of claims 15 to 24, wherein the 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 electrode;
Accommodating the conductive particles in the plurality of openings;
Including
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.
Any one of claims 15 to 25, wherein an electrolytic plating layer covering the electrode and the plurality of conductive particles arranged on the surface of the electrode is formed in a state where the circuit member and the transfer mold are overlapped with each other. The method for manufacturing an electrode with a terminal described in 1. The method for manufacturing an electrode with a terminal according to claim 26, 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 manufacturing an electrode with a terminal according to claim 26 or 27, wherein the transfer type is made of a flexible resin material. A first circuit member having a first substrate and a first electrode provided on the first substrate,
A second circuit member having a second electrode electrically connected to the first electrode,
A plurality of conductive particles interposed between the first electrode and the second electrode,
An electrolytic plating layer covering the first electrode and the plurality of conductive particles,
An insulating resin layer provided between the first circuit member and the second circuit member and adhered to the first circuit member and the second circuit member.
Equipped with a,
Particle size Ru 2.0~40μm der, the connection structure of the conductive particles. With a plurality of conductive particles having a particle size of 2.0 to 40 μm,
With one or more types of electrolytic plating solution,
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,
Kit for manufacturing electrodes with terminals. The kit for manufacturing an electrode with a terminal according to claim 30 , wherein the one or more kinds of electrolytic plating solutions include at least one of an electrolytic nickel plating solution and an electrolytic palladium plating solution. The kit for manufacturing an electrode with a terminal according to claim 30 or 31 , 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 any one of claims 30 to 32 , wherein the transfer type is made of a flexible resin material.

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