JP2005166438A - Circuit connecting material, and connection structure of circuit member using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit connecting material or the like by which better electrical connection between circuit electrodes confronted each other is attained and long-term reliability of electrical characteristics between the circuit electrodes is sufficiently improved, regardless of existence or non-existence of irregularities on the surface of the circuit electrodes. <P>SOLUTION: The circuit connecting material 50 includes an adhesive composition 51 and conductive particles 12 having projected portions on a surface side, and a storage elastic modulus at 40°C becomes 0.5 to 3GPa by hardening treatment, while an average coefficient of thermal expansion from 25 to 100°C becomes 30 to 200 ppm/°C by hardening treatment. Even if the adhesive composition enters between the conductive particles 12 and the circuit electrodes when pressurized, a pressure applied to the adhesive composition by the projected portions 14 becomes fully higher than a pressure applied by the conductive particles with no projected portion, by which the projected portions 14 penetrate the adhesive composition with ease and are brought into contact with the circuit electrodes, and a state in which the conductive particles 12 are kept to be connected to the circuit electrodes is held for a longer term. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a circuit connecting material and a circuit member connecting structure using the same.

  For connection between circuit members such as connection between liquid crystal display and tape carrier package (Tape Carrier Package: TCP), connection between flexible printed circuit (FPC) and TCP, or connection between FPC and printed wiring board A circuit connection material (for example, anisotropic conductive adhesive) in which conductive particles are dispersed in an adhesive is used. Recently, when a semiconductor silicon chip is mounted on a substrate, so-called flip chip mounting, in which the semiconductor silicon chip is directly mounted on the substrate face down without using a wire bond to connect circuit members, is performed. It has been broken. Also in this flip chip mounting, a circuit connection material such as an anisotropic conductive adhesive is used for connection between circuit members (see, for example, Patent Documents 1 to 5).

The circuit connection material described above generally contains an adhesive composition and conductive particles, and the conductive particles are formed by forming a metal plating layer on the surface of a core made of an organic polymer compound, for example. ing. The surface of the metal plating layer is usually flat.
JP 59-120436 A JP-A-60-191228 JP-A-1-251787 JP-A-7-90237 JP 2001-189171 A

  By the way, in recent years, with the downsizing and thinning of electronic devices, the density of circuits formed on circuit members has been increased, and the distance between adjacent electrodes and the width of electrodes tend to be very narrow. The formation of the circuit electrode is performed by a process in which a metal that is the source of the circuit is formed on the entire surface of the substrate, a resist is applied to the circuit electrode portion and cured, and the other portions are etched with an acid or a base. In the case of high-density circuits, if the metal irregularities formed on the entire surface of the substrate are large, the etching time differs between the concave and convex portions, so precise etching cannot be performed, and short circuits and disconnections between adjacent circuits occur. There is a problem of doing. For this reason, it is desired that unevenness is small on the electrode surface of the high-density circuit, that is, the electrode surface is flat.

  However, when such flat circuit electrodes facing each other are connected using the above-described conventional circuit connection material, an adhesive resin is used between the conductive particles contained in the circuit connection material and the flat electrode. There remains a problem that sufficient electrical connection and long-term reliability cannot be secured between the circuit electrodes.

  The present invention has been made in view of the above circumstances, and even if the surface of the circuit electrode is flat, it is possible to achieve good electrical connection between the facing circuit electrodes and to achieve a long-term electrical property between the circuit electrodes. It is an object of the present invention to provide a circuit connection material and a circuit member connection structure that can sufficiently enhance reliability.

  As a result of intensive studies to solve the above problems, the present inventors have found that the cause of the above problems is particularly the surface shape of the conductive particles. That is, since the conductive particles contained in the conventional circuit connection material have a flat surface, when the adhesive composition enters between the conductive particles and the circuit electrode, the pressure on the adhesive composition is small and the conductive particles are conductive. It has been found that it is difficult to sufficiently contact the particles and the circuit electrodes, and the electrical connection between the circuit electrodes becomes insufficient. And as a result of further earnest studies to solve the above-mentioned problems, the present inventors have found that the storage modulus at 40 ° C. and the average thermal expansion coefficient at 25 ° C. to 100 ° C. are within a specific range by the curing treatment. It has been found that the above problems can be solved by using a circuit connecting material having conductive particles having a specific surface shape, and the present invention has been completed.

  That is, the circuit connection material of the present invention is disposed so as to face the first circuit member, the first circuit member having the first circuit electrode formed on the main surface of the first circuit board, and the second circuit member. A second circuit member having a second circuit electrode formed on the main surface of the circuit board, and provided between the main surface of the first circuit member and the main surface of the second circuit member; A circuit connection material for forming a circuit connection member in a circuit member connection structure comprising a circuit connection member for connecting the second circuit members to each other, the circuit connection material comprising an adhesive composition, a surface Conductive particles having a plurality of conductive parts on the side, the storage elastic modulus at 40 ° C. is 0.5 to 3 GPa by the curing process, and the average heat from 25 ° C. to 100 ° C. by the curing process The expansion coefficient can be 30 to 200 ppm / ° C. The features.

  According to this circuit connection material, it is interposed between the first and second circuit members and is pressurized via the first and second circuit members. At this time, even if the adhesive composition enters between the conductive particles and the first and second circuit electrodes, the pressure applied to the adhesive composition from the protrusions of the conductive particles is higher than the conductive particles without the protrusions. Since it becomes sufficiently larger than the applied pressure, the protrusion of the conductive particles can easily penetrate the adhesive composition and come into contact with the first and second circuit electrodes. This is the same even when the surface of the first and / or second circuit electrode has irregularities and the adhesive composition easily enters between the conductive particles and the first and / or second circuit electrode. is there. And the state which the electrically-conductive particle and the 1st and 2nd circuit electrode contacted is hold | maintained over a long period of time by the hardening process of a circuit connection material.

  Moreover, this invention is a film-form circuit connection material formed by forming the said circuit connection material in a film form. This film-like circuit connecting material is film-like and easy to handle. For this reason, according to this film-like circuit connecting material, when connecting the first circuit member and the second circuit member, they can be easily interposed between them, Connection work with the circuit member of 2 can be performed easily.

  The present invention also provides a first circuit member in which a first circuit electrode is formed on a main surface of a first circuit board, a first circuit member disposed opposite to the first circuit member, and the main circuit board of the second circuit board. A second circuit member having a second circuit electrode formed on the surface; and a first circuit member and a second circuit member provided between the main surface of the first circuit member and the main surface of the second circuit member. A circuit member connection structure comprising: a circuit connection member for connecting members, wherein the circuit connection member contains an insulating substance and conductive particles having a plurality of projecting portions having conductivity on the surface side. The storage elastic modulus at 40 ° C. of the circuit connecting member is 0.5 to 3 GPa, and the average thermal expansion coefficient from 25 ° C. to 100 ° C. is 30 to 200 ppm / ° C. The two circuit electrodes are electrically connected through conductive particles.

  According to this circuit member connection structure, the storage elastic modulus at 40 ° C. of the circuit connection member is 0.5 to 3 GPa, and the average thermal expansion coefficient from 25 ° C. to 100 ° C. is 30 to 200 ppm / ° C. Accordingly, stress relaxation at the interface with the first circuit electrode or the second circuit electrode achieves high adhesive strength, and the state can be maintained for a long period of time.

  According to the circuit connection material and the circuit member connection structure of the present invention, even if the surface of the circuit electrode is flat, it is possible to achieve good electrical connection between the facing circuit electrodes and to improve the electrical characteristics between the circuit electrodes. Long-term reliability can be sufficiently increased.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. For the convenience of illustration, the dimensional ratios in the drawings do not necessarily match those described.

  FIG. 1 is a schematic cross-sectional view showing a first embodiment of a circuit member connection structure according to the present invention. The circuit member connection structure 1 according to the present embodiment includes a first circuit member 30 and a second circuit member 40 that face each other, and is provided between the first circuit member 30 and the second circuit member 40. Is provided with a circuit connecting member 10 for connecting them.

  The first circuit member 30 includes a circuit board (first circuit board) 31 and a circuit electrode (first circuit electrode) 32 formed on the main surface 31 a of the circuit board 31. The second circuit member 40 includes a circuit board 41 and a circuit electrode (first circuit electrode) 42 formed on the main surface 41 a of the circuit board 41. In the circuit boards 31 and 41, the surfaces of the circuit electrodes 32 and 42 are flat. In the present invention, “the surface of the circuit electrode is flat” means that the unevenness of the surface of the circuit electrode is 20 nm or less.

  In the circuit connection member 10, the storage elastic modulus in 40 degreeC of the material which comprises it is 0.5-3GPa, and the average thermal expansion coefficient from 25 degreeC to 100 degreeC is 30-200 ppm / degrees C. In addition, the storage elastic modulus in this invention was measured using the dynamic viscoelasticity measuring machine (Rhomotorics Scientific company make, RSA-II), and the average thermal expansion coefficient in this invention is TMA (made by Seiko Instruments Inc., It was measured using TMA / SS6000).

  The circuit connection member 10 contains an insulating material 11 and conductive particles 12. Although the details of the conductive particles 12 will be described later, as shown in FIGS. 2A to 2D, the conductive particles 12 have a plurality of protrusions 14 on the surface side.

  In the circuit member connection structure 1, the circuit electrode 32 and the circuit electrode 42 facing each other are electrically connected via the conductive particles 12. That is, the conductive particles 12 are in direct contact with both the circuit electrodes 32 and 42. Specifically, the protrusion 14 of the conductive particle 12 penetrates the insulating substance 11 and is in contact with the first circuit electrode 32 and the second circuit electrode 42.

  For this reason, the connection resistance between the circuit electrodes 32 and 42 is sufficiently reduced, and a good electrical connection between the circuit electrodes 32 and 42 becomes possible. Therefore, the flow of current between the circuit electrodes 32 and 42 can be made smooth, and the functions of the circuit can be fully exhibited.

  The circuit connecting member 10 has a storage elastic modulus at 40 ° C. of 0.5 to 3 GPa and an average coefficient of thermal expansion from 25 ° C. to 100 ° C. of 30 to 200 ppm / ° C., whereby the first circuit electrode Due to stress relaxation at the interface with the 32 or the second circuit electrode 42, high adhesive strength is realized, and the state can be maintained for a long period of time. That is, the change with time of the distance between the first circuit electrode 32 and the second circuit electrode 42 is sufficiently prevented, and the long-term reliability of the electrical characteristics between the first circuit electrode 32 and the second circuit electrode 42 is sufficiently enhanced. Can do.

  In addition, when the storage elastic modulus at 40 ° C. of the material constituting the circuit connection member 10 is less than 0.5 GPa, the adhesive strength is insufficient, and when it exceeds 3 GPa, the connection resistance in the circuit connection member 10 due to internal stress. Or the circuit connecting member 10 peels from the first or second circuit member 30 or 40. Further, when the average thermal expansion coefficient is less than 30 ppm / ° C., the adhesive strength becomes insufficient. When the average thermal expansion coefficient exceeds 200 ppm / ° C., the connection resistance at the circuit connection member 10 increases due to internal stress, or the circuit connection member 10 Peels from the first or second circuit member 30 or 40.

  Next, the configuration of the conductive particles 12 will be described in detail. FIG. 2 is a cross-sectional view showing various forms of conductive particles constituting the circuit connecting material according to the present invention. As shown in FIG. 2A, the conductive particles 12 are composed of conductive particles (main body portions) 12a and a plurality of protrusions 14 formed on the surfaces of the particles 12a. Here, the plurality of protrusions 14 are made of conductive metal. The particles 12a are composed of, for example, metal particles. Examples of the metal particles include nickel, copper, gold, silver, and cobalt. The particles 12a may have a metal layer formed on a nucleus composed of an organic polymer compound. The metal which comprises the projection part 14 is comprised with nickel, copper, gold | metal | money, silver, cobalt etc., for example. The metal constituting the particles 12a and the protrusions 14 may be the same or different.

  The protrusion 14 can be formed by depositing or plating a conductive metal on the surface of the particle 12a.

  The height H of the protrusions 14 of the conductive particles 12 is preferably 50 to 500 nm, and more preferably 100 to 300 nm. In addition, the distance S between the adjacent protrusions 14 is preferably 1000 nm or less, and more preferably 500 nm or less. Further, the distance S between the adjacent protrusions 14 is at least 50 nm or more so that the adhesive composition does not enter between the conductive particles and the circuit electrode, and the conductive particles and the circuit electrode are sufficiently brought into contact with each other. It is desirable. The height H of the protrusions 14 of the conductive particles 12 and the distance S between the adjacent protrusions 14 can be measured with an electron microscope.

  As shown in FIG. 2B, the conductive particles 12 may be composed of a nucleus 21 made of an organic polymer compound and a metal layer 22 formed on the surface of the nucleus 21. The core body 21 is composed of a core portion 21a and protrusions 21b formed on the surface of the core portion 21a, and the metal layer 22 has a plurality of protrusions 14 on the surface side.

  Examples of the organic polymer compound constituting the core portion 21a of the core body 21 include acrylic resin, styrene resin, benzoguanamine resin, silicone resin, polybutadiene resin, or a copolymer thereof. May be. The average particle size of the core 21a of the core 21 is preferably 50 to 500 nm.

  Examples of the organic polymer compound constituting the protruding portion 21b of the core 21 include acrylic resin, styrene resin, benzoguanamine resin, silicone resin, polybutadiene resin, or a copolymer thereof. May be. The organic polymer compound constituting the protruding portion 21b may be the same as or different from the organic polymer compound constituting the core portion 21a.

  The core 21 can be formed by adsorbing a plurality of protrusions 21b having a smaller diameter than the core 21a on the surface of the core 21a.

  The metal layer 22 formed on the core body 21 is made of, for example, copper, nickel, nickel alloy, silver, or silver alloy.

  The metal layer 22 can be formed by plating these metals on the core 21 using an electroless plating method.

  There are various nickel alloys depending on the additive added to the plating bath. Well-known nickel alloys include nickel-phosphorus, nickel-boron and the like. There are various types of silver alloys depending on the additives blended in the plating bath in the same manner as the nickel alloys.

  The thickness of the metal layer 22 (plating thickness) is preferably 50 to 170 nm, more preferably 50 to 150 nm. By setting the thickness of the metal layer 22 in such a range, the connection resistance between the circuit electrodes 32 and 42 can be further improved. If the thickness of the metal layer 22 is less than 50 nm, plating defects tend to occur and the connection resistance tends to increase. If the thickness exceeds 170 nm, condensation occurs between the conductive particles and a short circuit occurs between adjacent circuit electrodes. There is.

  Furthermore, as shown in FIG.2 (c), as for the electrically-conductive particle 12, the nucleus 21 may be comprised only in the core part 21a. The conductive particles 12 can be obtained by metal plating the surface of the core 21 and forming a metal layer 22 on the surface of the core 21. However, the protrusion 14 can be formed on the metal layer 22 by changing the thickness of the metal layer 22 by changing the plating conditions during metal plating. The plating conditions can be changed, for example, by making the plating solution concentration non-uniform by adding a plating solution having a higher concentration to the plating solution used first.

  Moreover, as shown in FIG.2 (d), the electrically-conductive particle 12 may be provided with the outermost layer 23 on the metal layer 22 with the smooth surface. In this embodiment, the protrusion 24 is formed on the surface side of the outermost layer 23. The outermost layer 23 is made of gold or palladium, and can be formed by displacement plating on the metal layer 22. However, the protrusion 24 can be formed on the outermost layer by changing the thickness of the outermost layer by changing the plating conditions in the same manner as described above during metal plating. Moreover, you may provide the outermost layer 23 on the surface of the metal layer 22 of the electrically-conductive particle 12 shown in FIG.2 (b). In this case, the protrusion 24 may be metal plated without changing the plating conditions.

  The thickness of the outermost layer is preferably 15 to 70 nm, and more preferably 25 to 50 nm. When the thickness of the outermost layer is less than 15 nm, it tends to be difficult to obtain a sufficient effect due to plating defects. Further, when the thickness of the outermost layer exceeds 70 nm, a good connection resistance can be achieved, but the production cost tends to be very high because the amount of the plating solution used increases synergistically. When the outermost layer is provided, the thickness of the metal layer 22b is preferably 70 to 170 nm. If the film thickness is less than 70 nm, plating defects (peeling) or the like tends to occur and the connection resistance tends to increase. If the film thickness exceeds 170 nm, a short circuit tends to occur between adjacent circuit electrodes.

  The circuit electrodes 32 and 42 are generally composed entirely of gold, silver, tin, a platinum group metal, or indium-tin oxide (ITO). It may be composed of a substance. Further, the material of the circuit boards 31 and 41 is not particularly limited, but is usually an organic insulating material, glass or silicon.

In the circuit member connection structure 1, the surface area of at least one of the first circuit electrode 32 and the second circuit electrode 42 is 15000 μm ² or less, and between the first circuit electrode 32 and the second circuit electrode 42. The average number of conductive particles in is preferably 3 or more. Here, the average number of conductive particles refers to the average value of the number of conductive particles per circuit electrode. In this case, the connection resistance between the circuit electrodes 32 and 42 facing each other can be more sufficiently reduced. Further, when the average number of conductive particles is 6 or more, even better connection resistance can be achieved. This is because the connection resistance between the circuit electrodes 32 and 42 facing each other is sufficiently low. Further, when the average number of conductive particles between the circuit electrodes 32 and 42 is 2 or less, the connection resistance becomes too high and the electronic circuit may not operate normally.

  In the circuit member connection structure 1, the glass transition temperature of the circuit connection member 10 is preferably 60 to 200 ° C. If the glass transition temperature is less than 60 ° C., the adhesive strength tends to decrease and the connection resistance tends to increase at a high temperature, and if it exceeds 200 ° C., a crack occurs in the circuit connection member 10, The interface stress with the first or second circuit member 30 or 40 tends to increase, and the adhesive strength tends to decrease.

  Specific examples of the first circuit member 30 and the second circuit member 40 include chip components such as a semiconductor chip, a resistor chip, and a capacitor chip, and a substrate such as a printed circuit board. These circuit members are usually provided with a large number (in some cases, a single number) of circuit electrodes (circuit terminals). In addition, as a form of the connection structure, there are a connection structure between the IC chip and the chip mounting substrate and a connection structure between the electric circuits.

  Moreover, in the said embodiment, although the insulating layer is not provided in the connection structure 1 of a circuit member, in the 1st circuit member 30, the 1st insulating layer is formed adjacent to the 1st circuit electrode 32. Alternatively, a second insulating layer may be formed adjacent to the second circuit electrode 42 in the second circuit member 40. The insulating layer is not particularly limited as long as it is made of an insulating material, but is usually made of an organic insulating material, silicon dioxide or silicon nitride.

[Method of manufacturing circuit member connection structure]
Next, the manufacturing method of the circuit member connection structure 1 described above will be described.

  First, the first circuit member 30, the second circuit member 40, and the circuit connection material described above are prepared. As the circuit connection material, for example, a circuit connection material (hereinafter referred to as a film-like circuit connection material) 50 formed into a film shape is prepared (see FIG. 3). The film-like circuit connecting material 50 contains an adhesive composition 51 that is cured by a curing process on the first circuit member 30 and the second circuit member 40, and the conductive particles 12, and is 40 ° C. by the curing process. The storage elastic modulus in can be 0.5 to 3 GPa, and the average thermal expansion coefficient from 25 ° C. to 100 ° C. can be 30 to 200 ppm / ° C. The thickness of the film-like circuit connecting material 50 is preferably 10 to 50 μm.

  Next, the film-like circuit connecting material 50 is placed on the first circuit member 30. Then, the second circuit member 40 is placed on the film-like circuit connecting material 50. Thereby, the film-like circuit connecting material 50 can be interposed between the first circuit member 30 and the second circuit member 40. At this time, the film-like circuit connecting material 50 is film-like and easy to handle. For this reason, according to the film-like circuit connecting material 50, when the first circuit member 30 and the second circuit member 40 are connected, they can be easily interposed between them. Connection work between the member 30 and the second circuit member 40 can be easily performed.

  Next, the film-like circuit connecting material 50 is heated and pressurized via the first circuit member 30 and the second circuit member 40 to perform a curing treatment, and between the first and second circuit members 30 and 40. The circuit connection member 10 is formed on the substrate. The curing treatment can be performed by a general method, and the method is appropriately selected depending on the adhesive composition. At this time, even if the adhesive composition enters between the conductive particles 12 and the first and second circuit electrodes 32 and 42, the pressure applied to the adhesive composition from the plurality of protrusions 14 of the conductive particles 12 is increased. The protrusion 14 of the conductive particles 12 easily penetrates the adhesive composition and contacts the first and second circuit electrodes 32 and 42 because the pressure is sufficiently larger than the pressure applied from the conductive particles having no protrusion. It becomes possible to do. This is because the surface of the first and / or second circuit electrodes 32 and 42 is uneven, and the adhesive composition is likely to enter between the conductive particles 12 and the first and / or second circuit electrodes 32 and 42. The same applies to the state. Then, the adhesive composition 51 is cured by curing the circuit connecting material, and a high adhesive strength with respect to the first circuit member 30 and the second circuit member 40 is realized. The state in which the two-circuit electrodes 32 and 42 are in firm contact is maintained for a long time.

  Accordingly, the connection resistance between the first and second circuit electrodes 32 and 42 facing each other can be sufficiently reduced irrespective of the presence or absence of irregularities on the surfaces of the first and / or second circuit electrodes 32 and 42, A good electrical connection between the first circuit electrode 32 and the second circuit electrode 42 can be achieved, and the long-term reliability of the electrical characteristics between the first and second circuit electrodes 32 and 42 can be sufficiently enhanced.

  In the above embodiment, the circuit member connection structure is manufactured using the film-like circuit connection material 50. However, instead of the film-like circuit connection material 50, a circuit connection material described later may be used. Even in this case, if the circuit connecting material is dissolved in a solvent and the solution is applied to either the first circuit member 30 or the second circuit member 40 and dried, the first and second circuit members 30 are used. , 40 can be interposed.

[Circuit connection material]
Next, the configuration of the above-described film-like circuit connecting material 50 will be described in detail.

  The film-like circuit connection material 50 is formed by forming a circuit connection material into a film shape, and the circuit connection material contains conductive particles 12 having protrusions 14 on the surface side and an adhesive composition 51. By the curing treatment, the storage elastic modulus at 40 ° C. can be 0.5 to 3 GPa, and the average thermal expansion coefficient from 25 ° C. to 100 ° C. can be 30 to 200 ppm / ° C. (preferably 30 to 100 ppm / ° C.). Consists of materials.

  The circuit connection material having a storage elastic modulus of less than 0.5 GPa at 40 ° C. due to curing treatment has insufficient adhesive strength, and the circuit connection material having a storage elastic modulus of greater than 3 GPa has a connection resistance at the circuit connection member 10 due to internal stress. Increase or the adhesive peels off. In addition, the circuit connection material having an average coefficient of thermal expansion from 25 ° C. to 100 ° C. of less than 30 ppm / ° C. due to the curing treatment has insufficient adhesive strength. The connection resistance at the portion increases or the adhesive peels off.

  The circuit connecting material is preferably one that can have a storage elastic modulus at 40 ° C. of 0.7 to 2 GPa by a curing treatment. In this case, an appropriate cohesive force can be obtained, and high adhesive strength can be expected due to stress relaxation between the circuit electrodes 32 and 42 and the interface of the circuit connection material.

  In addition, the circuit connection material is preferably a glass transition temperature of 60 to 200 ° C., more preferably 60 to 180 ° C. due to the curing treatment. In the circuit connection material having a glass transition temperature of less than 60 ° C. due to the curing treatment, the circuit member connection structure 1 tends to cause a decrease in adhesive strength and an increase in connection resistance at a high temperature. Since the circuit connection material exceeding ° C. is cured at a high temperature for a long time, the internal stress in the circuit connection member 10 may increase and cracks may occur. Further, since the interfacial stress with the circuit member 30 or 40 increases, the adhesive strength by the circuit connection member 10 tends to decrease.

  The adhesive composition contained in the circuit connecting material has adhesiveness, and is cured by a curing process for the first and second circuit members 30 and 40. Further, the adhesive composition has a storage elastic modulus at 40 ° C. of the circuit connecting material of 0.5 to 3 GPa (preferably 0.7 to 2 GPa) by curing treatment, and an average coefficient of thermal expansion from 25 ° C. to 100 ° C. is 30. Any adhesive composition may be used as long as it can be set to ˜200 ppm / ° C. (preferably 30 to 100 ppm / ° C.). Examples of such an adhesive composition include (1) an epoxy resin and a latent curing agent for the epoxy resin. (2) A composition containing (2) a radical polymerizable substance and a curing agent that generates free radicals upon heating, or a mixed composition of (1) and (2).

  First, a composition containing (1) an epoxy resin and a latent curing agent for the epoxy resin will be described.

  Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, Examples thereof include alicyclic epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, hydantoin type epoxy resins, isocyanurate type epoxy resins, and aliphatic chain epoxy resins. These epoxy resins may be halogenated or hydrogenated. Two or more of these epoxy resins may be used in combination.

  Any latent curing agent can be used as long as it can cure the epoxy resin. Examples of such latent curing agents include anionic polymerizable catalyst-type curing agents, cationic polymerizable catalyst-type curing agents, Addition type curing agents and the like can be mentioned. These can be used alone or as a mixture of two or more. Of these, anionic or cationic polymerizable catalyst-type curing agents are preferred because they are excellent in rapid curability and do not require chemical equivalent considerations.

  Examples of the anionic or cationic polymerizable catalyst-type curing agent include imidazole, hydrazide, boron trifluoride-amine complex, sulfonium salt, amine imide, diaminomaleonitrile, melamine and derivatives thereof, polyamine salt, dicyandiamide and the like. These modifications can also be used. Examples of the polyaddition type curing agent include polyamines, polymercaptans, polyphenols, and acid anhydrides.

  When a tertiary amine or imidazole is blended as an anionic polymerization type catalyst curing agent, the epoxy resin is cured by heating at a medium temperature of about 160 ° C. to 200 ° C. for several tens of seconds to several hours. For this reason, the pot life is relatively long, which is preferable.

  As the cationic polymerization type catalyst-type curing agent, for example, a photosensitive onium salt (an aromatic diazonium salt, an aromatic sulfonium salt or the like is mainly used) that cures an epoxy resin by irradiation with energy rays is preferable. In addition to irradiation with energy rays, there are aliphatic sulfonium salts and the like that are activated by heating to cure the epoxy resin. This type of curing agent is preferable because it has a feature of fast curing.

  When these latent hardeners are coated with polymer materials such as polyurethane or polyester, metal thin films such as nickel or copper, and inorganic materials such as calcium silicate, the pot life is extended. This is preferable because it is possible.

  Next, a composition containing (2) a radical polymerizable substance and a curing agent that generates free radicals upon heating will be described.

  The radical polymerizable substance is a substance having a functional group that is polymerized by radicals. Examples of such radically polymerizable substances include acrylate (including corresponding methacrylates; the same shall apply hereinafter) compounds, acryloxy (including corresponding methacryloxy; the same shall apply hereinafter) compounds, maleimide compounds, citraconic imide resins, nadiimide resins, and the like. It is done. The radically polymerizable substance may be used in a monomer or oligomer state, and the monomer and oligomer may be used in combination.

  Specific examples of the acrylate compound include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, 2-hydroxy-1,3- Diacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate , Tris (acryloyloxyethyl) isocyanurate, urethane acrylate and the like. These can be used alone or in admixture of two or more. Moreover, you may use polymerization inhibitors, such as a hydroquinone and methyl ether hydroquinones, suitably if needed. Furthermore, from the viewpoint of improving heat resistance, the acrylate compound preferably has at least one substituent selected from the group consisting of a dicyclopentenyl group, a tricyclodecanyl group, and a triazine ring.

  The maleimide compound contains at least two maleimide groups in the molecule. Examples of such maleimide compounds include 1-methyl-2,4-bismaleimide benzene, N, N′-m-phenylene bismaleimide, N, N′-p-phenylene bismaleimide, N, N′-m. -Toluylene bismaleimide, N, N'-4,4-biphenylene bismaleimide, N, N'-4,4- (3,3'-dimethylbiphenylene) bismaleimide, N, N'-4,4- ( 3,3′-dimethyldiphenylmethane) bismaleimide, N, N′-4,4- (3,3′-diethyldiphenylmethane) bismaleimide, N, N′-4,4-diphenylmethane bismaleimide, N, N′- 4,4-diphenylpropane bismaleimide, N, N′-3,3′-diphenylsulfone bismaleimide, N, N′-4,4-diphenyl ether bismale 2,2-bis (4- (4-maleimidophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-4,8- (4-maleimidophenoxy) phenyl) propane, 1,1- Bis (4- (4-maleimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- (4-maleimidophenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4- And maleimidephenoxy) phenyl) hexafluoropropane, which can be used alone or in admixture of two or more.

  The citraconic imide resin is obtained by polymerizing a citraconic imide compound having at least one citraconic imide group in the molecule. Examples of the citraconimide compound include phenyl citraconimide, 1-methyl-2,4-biscitraconimide benzene, N, N′-m-phenylene biscitraconimide, N, N′-p-phenylene biscitraconimide, N , N′-4,4-biphenylenebiscitraconimide, N, N′-4,4- (3,3-dimethylbiphenylene) biscitraconimide, N, N′-4,4- (3,3-dimethyldiphenylmethane ) Biscitraconimide, N, N′-4,4- (3,3-diethyldiphenylmethane) biscitraconimide, N, N′-4,4-diphenylmethane biscitraconimide, N, N′-4,4-diphenyl Propane biscitraconimide, N, N'-4,4-diphenyl ether biscitraconimide, N, N'- , 4-Diphenylsulfonebiscitraconimide, 2,2-bis (4- (4-citraconimidophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-citraconimidephenoxy) ) Phenyl) propane, 1,1-bis (4- (4-citraconimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- (4-citraconimidophenoxy) phenoxy) -2-cyclohexyl Examples include benzene and 2,2-bis (4- (4-citraconimidophenoxy) phenyl) hexafluoropropane. These can be used alone or in admixture of two or more.

  The nadiimide resin is obtained by polymerizing a nadiimide compound having at least one nadiimide group in the molecule. Examples of the nadiimide compound include phenyl nadiimide, 1-methyl-2,4-bisnadiimidebenzene, N, N′-m-phenylenebisnadiimide, N, N′-p-phenylenebisnadiimide, N, N′— 4,4-biphenylenebisnadiimide, N, N′-4,4- (3,3-dimethylbiphenylene) bisnadiimide, N, N′-4,4- (3,3-dimethyldiphenylmethane) bisnadiimide, N, N ′ -4,4- (3,3-diethyldiphenylmethane) bisnadiimide, N, N'-4,4-diphenylmethane bisnadiimide, N, N'-4,4-diphenylpropane bisnadiimide, N, N'-4,4 -Diphenyl ether bisnadiimide, N, N'-4,4-diphenylsulfone bisnadiimide, 2,2-bis (4- (4-nazii Dophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-nadiimidophenoxy) phenyl) propane, 1,1-bis (4- (4-nadiimidophenoxy) phenyl ) Decane, 4,4′-cyclohexylidene-bis (1- (4-nadiimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-nadiimidophenoxy) phenyl) hexafluoro Propane is mentioned. These can be used alone or in admixture of two or more.

［上記式中、ｎは１〜３の整数を示す。］ Moreover, it is preferable to use together with the radical polymerizable substance a radical polymerizable substance having a phosphate structure represented by the following chemical formula (I). In this case, since the adhesive strength to the surface of an inorganic material such as metal is improved, it is suitable for bonding circuit electrodes.

[In the above formula, n represents an integer of 1 to 3. ]

  The radically polymerizable substance having a phosphoric ester structure is obtained by reacting phosphoric anhydride with 2-hydroxyethyl (meth) acrylate. Specific examples of the radical polymerizable substance having a phosphate structure include mono (2-methacryloyloxyethyl) acid phosphate, di (2-methacryloyloxyethyl) acid phosphate, and the like. These can be used alone or in admixture of two or more.

  The blending amount of the radical polymerizable substance having the phosphate ester structure represented by the chemical formula (I) is 0.01 to 50 with respect to 100 parts by mass in total of the radical polymerizable substance and the film forming material to be blended as necessary. It is preferable that it is a mass part, and 0.5-5 mass parts is more preferable.

  The radical polymerizable substance can be used in combination with allyl acrylate. In this case, it is preferable that the compounding quantity of allyl acrylate is 0.1-10 mass parts with respect to 100 mass parts in total of a radically polymerizable substance and the film formation material mix | blended if necessary, 0.5 -5 mass parts is more preferable.

  The curing agent that generates free radicals upon heating is a curing agent that decomposes upon heating to generate free radicals. Examples of such curing agents include peroxide compounds and azo compounds. Such a curing agent is appropriately selected depending on the intended connection temperature, connection time, pot life, and the like. From the viewpoint of high reactivity and improvement in pot life, organic peroxides having a half-life of 10 hours at a temperature of 40 ° C. or more and a half-life of 1 minute at a temperature of 180 ° C. or less are preferred. An organic peroxide having a temperature of 60 ° C. or higher and a half-life of 1 minute is 170 ° C. or lower is more preferable.

  When the connection time is 25 seconds or less, the amount of the curing agent is 2 parts with respect to a total of 100 parts by mass of the radically polymerizable substance and the film-forming material blended as necessary to obtain a sufficient reaction rate. It is preferably about 10 to 10 parts by mass, and more preferably 4 to 8 parts by mass. In addition, the compounding quantity of the hardening | curing agent in the case where connection time is not limited may be 0.05-20 mass parts with respect to a total of 100 mass parts of a radically polymerizable substance and the film formation material mix | blended as needed. Preferably, 0.1-10 mass parts is more preferable.

  More specifically, examples of the curing agent that generates free radicals upon heating include diacyl peroxide, peroxydicarbonate, peroxyester peroxyketal, dialkyl peroxide, hydroperoxide, and silyl peroxide. Further, from the viewpoint of suppressing the corrosion of the circuit electrodes 32 and 42, the curing agent preferably has a chlorine ion or organic acid concentration of 5000 ppm or less contained in the curing agent, and further, an organic matter generated after thermal decomposition. Those with less acid are more preferred. Specific examples of such a curing agent include peroxyesters, dialkyl peroxides, hydroperoxides, silyl peroxides, and the like, and it is more preferable to select them from peroxyesters that provide high reactivity. In addition, the said hardening | curing agent can be mixed and used suitably.

  Peroxyesters include cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxynoedecanoate, and t-hexyl. Peroxyneodecanodate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanate, 2,5-dimethyl-2,5-di (2-ethyl) Hexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanate, t-hexylperoxy-2-ethylhexanate, t-butylperoxy-2-ethylhexanate T-butylperoxyisobutyrate, 1,1-bis (t-butylperoxy) cyclohexane, t Hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanonate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (m-toluoylperoxy ) Hexane, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxyacetate and the like.

  Dialkyl peroxides include α, α ′ bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and t-butylcumi. Examples include ruperoxide.

  Examples of the hydroperoxide include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

  Diacyl peroxides include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, benzoyl Examples include peroxytoluene and benzoyl peroxide.

  Examples of peroxydicarbonate include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxymethoxyperoxydicarbonate, di ( 2-ethylhexyl peroxy) dicarbonate, dimethoxybutyl peroxydicarbonate, di (3-methyl-3-methoxybutylperoxy) dicarbonate and the like.

  Peroxyketals include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t- Butyl peroxy) -3,3,5-trimethylcyclohexane, 1,1- (t-butylperoxy) cyclododecane, 2,2-bis (t-butylperoxy) decane and the like.

  Examples of silyl peroxides include t-butyltrimethylsilyl peroxide, bis (t-butyl) dimethylsilyl peroxide, t-butyltrivinylsilyl peroxide, bis (t-butyl) divinylsilyl peroxide, and tris (t-butyl). Examples thereof include vinylsilyl peroxide, t-butyltriallylsilyl peroxide, bis (t-butyl) diallylsilyl peroxide, and tris (t-butyl) allylsilyl peroxide.

  These curing agents can be used alone or in admixture of two or more, and may be used by mixing a decomposition accelerator, an inhibitor and the like. Further, these curing agents may be coated with a polyurethane-based or polyester-based polymer substance to form microcapsules. A microencapsulated curing agent is preferred because the pot life is extended.

  You may add and use a film formation material for the circuit connection material of this embodiment as needed. The film-forming material is a material that solidifies a liquid material and forms a composition composition into a film shape to facilitate the handling of the film and impart mechanical properties that do not easily tear, break, or stick. Yes, it can be handled as a film in a normal state (normal temperature and normal pressure). Examples of the film forming material include phenoxy resin, polyvinyl formal resin, polystyrene resin, polyvinyl butyral resin, polyester resin, polyamide resin, xylene resin, polyurethane resin and the like. Among these, a phenoxy resin is preferable because of excellent adhesiveness, compatibility, heat resistance, and mechanical strength.

  A phenoxy resin is a resin obtained by reacting a bifunctional phenol and epihalohydrin until they are polymerized or by polyaddition of a bifunctional epoxy resin and a bifunctional phenol. The phenoxy resin, for example, reacts 1 mol of a bifunctional phenol with 0.985 to 1.015 mol of epihalohydrin in a non-reactive solvent at a temperature of 40 to 120 ° C. in the presence of a catalyst such as an alkali metal hydroxide. Can be obtained. Moreover, as a phenoxy resin, especially from the viewpoint of the mechanical characteristics and thermal characteristics of the resin, the mixing equivalent ratio of the bifunctional epoxy resin and the bifunctional phenols is epoxy group / phenol hydroxyl group = 1 / 0.9- 1/1, organic amides, ethers, ketones, lactones, alcohols, etc. having a boiling point of 120 ° C. or higher in the presence of catalysts such as alkali metal compounds, organophosphorus compounds, cyclic amine compounds, etc. What was obtained by heating to 50-200 degreeC and carrying out the polyaddition reaction on the conditions whose reaction solid content is 50 mass parts or less in a solvent is preferable.

  Examples of the bifunctional epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, biphenyl diglycidyl ether, and methyl-substituted biphenyl diglycidyl ether. Bifunctional phenols have two phenolic hydroxyl groups. Examples of the bifunctional phenols include hydroquinones, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, bisphenol fluorene, methyl-substituted bisphenol fluorene, bisphenols such as dihydroxybiphenyl and methyl-substituted dihydroxybiphenyl. The phenoxy resin may be modified (for example, epoxy-modified) with a radical polymerizable functional group or other reactive compound. You may use a phenoxy resin individually or in mixture of 2 or more types.

  The circuit connection material of this embodiment may further contain a polymer or copolymer containing at least one of acrylic acid, acrylic acid ester, methacrylic acid ester, and acrylonitrile as a monomer component. Here, since it is excellent in stress relaxation, it is preferable to use together the copolymer type acrylic rubber containing glycidyl acrylate and glycidyl methacrylate containing a glycidyl ether group. The weight average molecular weight of these acrylic rubbers is preferably 200,000 or more from the viewpoint of increasing the cohesive strength of the adhesive.

  The blending amount of the conductive particles 12 is preferably 0.1 to 30 parts by volume with respect to 100 parts by volume of the adhesive composition, and the blending amount can be properly used depending on the application. From the viewpoint of preventing short circuit of the circuit electrode due to excessive conductive particles 12, the blending amount of the conductive particles 12 is more preferably 0.1 to 10 parts by volume.

  The circuit connection material of this embodiment further includes rubber fine particles, fillers, softeners, accelerators, anti-aging agents, colorants, flame retardants, thixotropic agents, coupling agents, phenol resins, melamine resins, Isocyanates can also be contained.

  The rubber fine particles have an average particle size of not more than twice the average particle size of the conductive particles 12 to be blended, and a storage elastic modulus at room temperature (25 ° C.) at the room temperature of the conductive particles 12 and the adhesive composition. What is necessary is just to be 1/2 or less of the storage elastic modulus. In particular, it is preferable that the fine particles whose material of the rubber fine particles is silicone, acrylic emulsion, SBR, NBR, or polybutadiene rubber are used alone or in admixture of two or more. These three-dimensionally crosslinked rubber fine particles have excellent solvent resistance and are easily dispersed in the adhesive composition.

  It is preferable to include a filler in the circuit connection material because connection reliability and the like are improved. The filler can be used if its maximum diameter is ½ or less of the particle diameter of the conductive particles 12. If the maximum diameter is 1/2 or less of the particle diameter of the conductive particles, it can be used. Moreover, when using together the particle | grains which do not have electroconductivity, if it is below the diameter of the particle | grains which do not have electroconductivity, it can be used. It is preferable that the compounding quantity of a filler is 5-60 volume parts with respect to 100 volume parts of adhesive compositions. If the blending amount exceeds 60 parts by volume, the effect of improving the connection reliability tends to be saturated, and if it is less than 5 parts by volume, the effect of adding the filler tends to be insufficient.

  As said coupling agent, the compound containing a vinyl group, an acryl group, an epoxy group, or an isocyanate group is preferable since adhesiveness improves.

  In the circuit connection material, the conductive particles 12 are preferably added in an amount of 0.1 to 30 parts by volume with respect to 100 parts by volume of the adhesive composition. In addition, in order to prevent the short circuit of the adjacent circuit electrode by the excessive conductive particle 12, etc., it is more preferable to add 0.1-10 volume parts.

  The film-like circuit connection material 50 is produced by applying the circuit connection material on a support (PET (polyethylene terephthalate) film or the like) using a coating apparatus (not shown) and drying with hot air for a predetermined time. can do.

(Preparation of conductive particles)
Suspension polymerization is performed using benzoyl peroxide as a polymerization initiator by changing the mixing ratio of tetramethylolmethanetetraacrylate, divinylbenzene and styrene monomer, and the resulting polymer is classified to have a particle size of about 5 μm. Nucleus was obtained.

  The surface of the obtained core was subjected to electroless Ni plating treatment to obtain conductive particles No. 1 having a uniform Ni layer (metal layer) having a thickness of 100 nm. 1 was obtained.

  In addition, by changing the plating thickness according to the amount of plating solution charged, the processing temperature, and the time during the Ni plating process, the conductive particle No. 1 is formed on the surface of the conductive particles No. 1; 2 was obtained.

  In addition, conductive particle No. 1 is plated by Au to a thickness of 25 nm to form an Au layer having a uniform thickness. 3 was obtained.

  Further, conductive particle No. The Au layer having a plurality of protrusions is formed by substitution plating of Au on the conductive particles No. 2. 4 was obtained.

Each of the above conductive particles No. 1-4 were observed using an electron microscope (manufactured by Hitachi, Ltd., S-800), and the height of the protrusion and the distance between adjacent protrusions were measured. The results are shown in Table 1.

(Example 1)
50 parts by mass of a bisphenol A type epoxy resin and 50 parts by mass of an epoxy resin latent curing agent (trade name NOVACURE 3941HPS, manufactured by Asahi Ciba Co., Ltd.) were mixed. With respect to 100 parts by volume of the adhesive composition, the conductive particles No. No. 2 is dispersed in 5 parts by volume, and circuit connection material No. 2 is dispersed. 1 was obtained. In addition, NovaCure 3941HPS, which is a latent curing agent, was obtained by dispersing a microcapsule type curing agent having an average particle size of 5 μm having an imidazole modified body as a core and covering the surface with polyurethane in a liquid bisphenol F type epoxy resin. It is a master batch type curing agent.

(Example 2)
Conductive particle No. 1 in Example 1. In place of conductive particles No. 2 4 except that circuit connection material No. 4 was used in the same manner as in Example 1. 2 was obtained.

(Example 3)
50 g of phenoxy resin (trade name PKHC, manufactured by Union Carbide Co., Ltd., average weight molecular weight 45,000) was dissolved in a mixed solvent of toluene / ethyl acetate = 50/50 (mass ratio) to obtain a phenoxy having a solid content of 40% by mass. A resin solution was obtained.

  Next, a phenoxy resin solution weighed out from the above solution so as to contain 10 g of a solid content, 40 g of a bisphenol A type epoxy resin, and a latent curing agent for epoxy resin (trade name Novacure 3941HPS manufactured by Asahi Ciba Co., Ltd.) And an adhesive composition-containing liquid was obtained. With respect to 100 parts by volume of the adhesive composition-containing liquid, conductive particle No. 5 parts by volume of 2 was dispersed to prepare a circuit connecting material-containing solution.

  And this circuit connection material containing liquid is apply | coated to an 80-micrometer-thick polyethylene terephthalate (PET) film which surface-treated one side using a coating apparatus, and thickness is put on PET film by hot-air drying for 10 minutes at 70 degreeC. 20 μm film-like circuit connection material No. 3 was obtained.

Example 4
While stirring 400 parts by mass of polycaprolactone diol having an average molecular weight of 800, 131 parts by mass of 2-hydroxypropyl acrylate, 0.5 parts by mass of dibutyltin dilaurate as a catalyst and 1.0 part by mass of hydroquinone monomethyl ether as a polymerization inhibitor Heat to 50 ° C. and mix. Next, 222 parts by mass of isophorone diisocyanate was dropped into this mixed solution, and the mixture was further heated to 80 ° C. while stirring to carry out a urethanization reaction. After confirming that the reaction rate of the isocyanate group was 99% or more, the reaction temperature was lowered to obtain urethane acrylate.

  Next, a phenoxy resin solution weighed out from the phenoxy resin solution prepared in Example 3 so as to contain 50 g of solid content, 49 g of the urethane acrylate, 1 g of phosphate ester acrylate, and free radicals are generated by heating. Then, 5 g of t-hexylperoxy-2-ethylhexanate as a curing agent to be mixed was mixed to obtain an adhesive composition-containing liquid. And conductive particle No. with respect to 100 volume parts of this adhesive composition containing liquid. 5 parts by volume of 2 was dispersed to prepare a circuit connecting material-containing solution.

  And this circuit connection material containing liquid is apply | coated to the PET film of thickness 80micrometer which carried out surface treatment of one side using a coating apparatus, and the film form whose thickness is 20 micrometers on PET film by hot-air drying for 10 minutes at 70 degreeC. Circuit connection material No. 4 was obtained.

(Comparative Example 1)
Conductive particle No. 1 in Example 1. In place of conductive particles No. 2 1 except that circuit connection material No. 1 was used in the same manner as in Example 1. 5 was obtained.

(Comparative Example 2)
Conductive particle No. 1 in Example 1. In place of conductive particles No. 2 3 except that circuit connection material No. 3 was used in the same manner as in Example 1. 6 was obtained.

(Connection of circuit members)
As a first circuit member, a flexible circuit board (FPC) having a three-layer structure comprising a polyimide film (thickness 40 μm), a copper foil (thickness 18 μm), and an adhesive for bonding the polyimide film and the copper foil. Prepared. For the copper circuit of this flexible circuit board, the line width was 7 μm and the pitch was 30 μm.

  Subsequently, indium-tin oxide (ITO) is formed by vapor deposition on a glass substrate (thickness 1.1 mm), and a glass substrate (surface resistance <20Ω) having ITO circuit electrodes on the surface as a second circuit member. (Hereinafter referred to as second circuit member A). About this 2nd circuit member A, the surface of an ITO circuit electrode is observed using an electron microscope (made by Hitachi, S-800), and the unevenness | corrugation height difference (thickness difference) of the surface of an ITO circuit electrode is measured. As a result, the height difference was 4 nm.

  On the other hand, indium zinc oxide (IZO) is formed by vapor deposition on a glass substrate (thickness 1.1 mm), and a glass substrate (surface resistance <20Ω) having an IZO circuit electrode on the surface is formed as a second circuit member. It produced (henceforth the 2nd circuit member B). With respect to the second circuit member B, the height difference (thickness difference) of the irregularities on the surface of the IZO circuit electrode was measured in the same manner as described above, and the height difference was 1.0 nm.

  And the circuit connection material of Examples 1-2 and Comparative Examples 1-2 was apply | coated and dried so that it might become 1 mm in width on 2nd circuit member A, B. After that, the second circuit members A and B are arranged side by side, and the circuit connection material is provided by the FPC which is the first circuit member and the second circuit members A and B with respect to the second circuit members A and B. The FPC was arranged so as to be sandwiched. Next, the FPC and the second circuit members A and B were connected by pressurizing the circuit connecting material through the FPC and the second circuit members A and B while heating them at 180 ° C. and 3 MPa for 10 seconds. Thus, a circuit member connection structure in which two second circuit members A and B were arranged in parallel on the FPC was obtained.

  Moreover, in the film-form circuit connection material (width 1mm) of Examples 3-4, after sticking the adhesive surface on the 2nd circuit members A and B, it heated at 70 degreeC and 0.5 MPa for 5 second. The film-like circuit connecting material was temporarily connected to the second circuit members A and B by applying pressure. Next, after peeling off the PET film, the FPC was arranged so that the film-like circuit connecting material was sandwiched between the FPC and the second circuit members A and B. Next, the FPC and the second circuit member were connected by pressurizing the film-like circuit connecting material through the FPC and the second circuit members A and B while heating at 180 ° C. and 3 MPa for 10 seconds. Thus, a circuit member connection structure in which two second circuit members A and B were arranged in parallel on the FPC was obtained.

(Measurement of connection resistance)
With respect to the circuit member connection structure obtained as described above, the connection resistance value between the circuit electrode of the FPC and the circuit electrodes of the second circuit members A and B was measured using a multimeter. The connection resistance value was measured at the initial stage (immediately after connection) and after being held for 1000 hours (high temperature and high humidity treatment) in a high temperature and high humidity bath at 80 ° C. and 95% RH. Table 2 shows the measurement results of the connection resistance value. In Table 2, the connection resistance value is represented by the sum (x + 3σ) of an average value of 150 resistances between adjacent circuits and a value obtained by triple the standard deviation.

(Number of conductive particles present on circuit electrode)
The number of conductive particles present on each circuit electrode in the circuit member connection structure was counted visually with a microscope. Note that the average value of the number of conductive particles present on 151 electrodes was defined as the number of conductive particles on the circuit electrode. The results are shown in Table 2.

(Measurement of storage modulus and average thermal expansion coefficient of circuit connecting member)
The storage elastic modulus in 40 degreeC after the hardening process of the circuit connection material of Examples 1-4 and Comparative Examples 1-3 exists in the range of 0.5-3 GPa, and the average thermal expansion coefficient from 25 degreeC to 100 degreeC is It confirmed that it existed in the range of 30-200 ppm / degreeC.

  As is apparent from the results shown in Table 2, the initial connection resistance in the circuit member connection structure using the circuit connection material according to Example 1 is that the circuit electrode formed on the second circuit member is an ITO circuit electrode. Regardless of the presence of the IZO circuit electrode, it was found that the connection resistance was sufficiently reduced compared to the initial connection resistance in the circuit member connection structure using the circuit connection material according to Comparative Example 1. Therefore, according to the circuit connection material of the present invention, even when the surface of the circuit electrode is flat, the connection resistance between the circuit electrodes is sufficiently reduced as compared with the circuit connection material containing conductive particles having no protrusions. It was found that the electrical connection between the circuit electrodes can be improved.

  Moreover, in the circuit member connection structure using the circuit connection material according to the first embodiment, the circuit electrode formed on the second circuit member is an ITO circuit electrode or an IZO circuit electrode, regardless of whether it is an IZO circuit electrode. The difference between the connection resistance value after the high-humidity treatment and the initial connection resistance value is sufficiently small, and the rise from the initial connection resistance value is sufficiently suppressed, whereas the circuit connection material according to Comparative Example 1 is used. In the connection structure of the circuit member used, it cannot be said that the difference between the connection resistance value after the high temperature and high humidity treatment and the initial connection resistance value is small, and the rise from the initial connection resistance value is not sufficiently suppressed. I understood that. In particular, in the circuit member connection structure using the circuit connection material according to Comparative Example 1, when the IZO circuit electrode is used as the circuit electrode, the connection resistance value after the high-temperature and high-humidity treatment and the initial connection resistance value The difference was extremely large. Therefore, the circuit connection material of the present invention can sufficiently reduce the connection resistance between the circuit electrodes even when the surface of the circuit electrode is flat as compared with the circuit connection material containing conductive particles having no protrusions. However, it was found that the connection resistance can be maintained over a long period of time.

  Further, in the circuit member connection structure using the circuit connection material according to Examples 2 to 4, regardless of whether the circuit electrode formed on the second circuit member is an ITO circuit electrode or an IZO circuit electrode, It was found that the connection resistance in the initial stage was sufficiently reduced.

  In addition, in the circuit member connection structure using the circuit connection material according to Examples 2 to 4, regardless of whether the circuit electrode formed on the second circuit member is an ITO circuit electrode or an IZO circuit electrode It was found that the difference between the connection resistance value after the high temperature and high humidity treatment and the initial connection resistance value was sufficiently small, and the rise from the initial connection resistance value was sufficiently suppressed. On the other hand, in the circuit member connection structure using the circuit connection material according to Comparative Example 2, regardless of whether the circuit electrode formed on the second circuit member is an ITO circuit electrode or an IZO circuit electrode, The difference between the connection resistance value after the high-temperature and high-humidity treatment and the initial connection resistance value cannot be said to be small, and it was found that the increase from the initial connection resistance value was not sufficiently suppressed. In particular, in the circuit member connection structure using the circuit connection material according to Comparative Example 2, when the IZO circuit electrode is used as the circuit electrode, the connection resistance value after the high temperature and high humidity treatment and the initial connection resistance value The difference was extremely large.

  The circuit connecting material of the present invention is useful for connecting circuit members such as chip parts such as semiconductor chips, resistor chips and capacitor chips, and substrates such as printed boards.

It is sectional drawing which shows one Embodiment of the connection structure of the circuit member which concerns on this invention. It is sectional drawing which shows the various form of the electrically-conductive particle which comprises the circuit connection material which concerns on this invention. It is sectional drawing which shows one Embodiment of the film-form circuit connection material which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Circuit member connection structure, 10 ... Circuit connection member, 11 ... Insulative substance, 12 ... Conductive particle, 12a ... Core body, 12b ... Metal layer, 14 ... Projection, 30 ... First circuit member, 31 ... Circuit Substrate (first circuit board), 31a ... main surface, 32 ... circuit electrode (first circuit electrode), 40 ... second circuit member, 41 ... circuit substrate (second circuit board), 41a ... main surface 42 ... Circuit electrode (second circuit electrode), 43 ... Insulating layer (second insulating layer), 50 ... Film-like circuit connecting material, 51 ... Adhesive composition.

Claims (21)

A first circuit member having a first circuit electrode formed on the main surface of the first circuit board;
A second circuit member disposed opposite to the first circuit member and having a second circuit electrode formed on a main surface of the second circuit board;
A circuit connection member provided between the main surface of the first circuit member and the main surface of the second circuit member, and connecting the first and second circuit members;
A circuit connection material for forming the circuit connection member in a circuit member connection structure comprising:
The circuit connection material contains an adhesive composition and conductive particles provided with a plurality of protrusions having conductivity on the surface side,
The storage modulus at 40 ° C. can be 0.5-3 GPa by the curing treatment, and the average thermal expansion coefficient from 25 ° C. to 100 ° C. can be 30-200 ppm / ° C. by the curing treatment.
A circuit connection material characterized by that. The protrusion has a height of 50 to 500 nm,
The circuit connection material according to claim 1, wherein a distance between adjacent protrusions is 1000 nm or less. The conductive particles have a conductive main body,
The plurality of protrusions are provided on the surface of the main body,
The circuit connection material according to claim 1 or 2, wherein The conductive particles include a nucleus composed of an organic polymer compound, and a metal layer composed of copper, nickel, nickel alloy, silver or silver alloy formed on the nucleus,
The plurality of protrusions are provided on the surface side of the metal layer,
The circuit connection material according to claim 1, wherein the metal layer has a thickness of 50 to 170 nm. The conductive particles have an outermost layer made of gold or palladium, and the plurality of protrusions are provided on the surface side of the outermost layer;
5. The circuit connection material according to claim 1, wherein the outermost layer has a thickness of 15 to 70 nm. The said adhesive composition contains an epoxy resin and the latent hardening | curing agent of the said epoxy resin, The circuit connection material as described in any one of Claims 1-5 characterized by the above-mentioned. The circuit connection material according to any one of claims 1 to 6, wherein the adhesive composition contains a radical polymerizable substance and a curing agent that generates free radicals upon heating. The circuit connection material according to any one of claims 1 to 7, wherein the glass transition temperature can be 60 to 200 ° C by a curing treatment. The circuit connection material according to claim 1, further comprising a film forming material. The circuit connection material according to claim 9, wherein the film forming material is a phenoxy resin. A circuit connection material according to any one of claims 1 to 10, wherein the circuit connection material is formed into a film shape. A first circuit member having a first circuit electrode formed on the main surface of the first circuit board;
A second circuit member disposed opposite to the first circuit member and having a second circuit electrode formed on a main surface of the second circuit board;
A circuit connection member provided between the main surface of the first circuit member and the main surface of the second circuit member, and connecting the first and second circuit members;
A circuit member connection structure comprising:
The circuit connection member contains an insulating material and conductive particles including a plurality of protrusions having conductivity on the surface side,
The circuit connecting member has a storage elastic modulus at 40 ° C. of 0.5 to 3 GPa and an average coefficient of thermal expansion from 25 ° C. to 100 ° C. of 30 to 200 ppm / ° C.,
The circuit member connection structure, wherein the first circuit electrode and the second circuit electrode are electrically connected via the conductive particles. The protrusion has a height of 50 to 500 nm,
The circuit connection material according to claim 12, wherein a distance between adjacent protrusions is 1000 nm or less. The circuit connection material according to claim 12, wherein the conductive particles have a conductive main body, and the plurality of protrusions are provided on a surface of the main body. The conductive particles include a nucleus composed of an organic polymer compound, and a metal layer composed of copper, nickel, nickel alloy, silver or silver alloy formed on the nucleus,
The plurality of protrusions are provided on the surface side of the metal layer,
The circuit connection material according to claim 11 or 12, wherein the metal layer has a thickness of 50 to 150 nm. The conductive particles have an outermost layer made of gold or palladium, and the plurality of protrusions are provided on the surface side of the outermost layer;
The circuit connection material according to claim 12, wherein the outermost layer has a thickness of 15 to 70 nm. The circuit connection material according to any one of claims 12 to 16, wherein a glass transition temperature of the circuit connection member is 60 to 200 ° C. A first insulating layer formed on a main surface of the first circuit member and adjacent to the first circuit electrode;
A second insulating layer formed on the main surface of the second circuit member and adjacent to the second circuit electrode;
The circuit member connection structure according to any one of claims 12 to 17, wherein the first and second insulating layers are made of an organic insulating material, silicon dioxide, or silicon nitride. The surface area of at least one of the first and second circuit electrodes is 15,000 μm ² or less, and the average number of conductive particles between the first circuit electrode and the second circuit electrode is 3 or more. The circuit member connection structure according to any one of claims 12 to 18, wherein the connection structure is a circuit member connection structure. 20. At least one of the first and second circuit electrodes has a surface layer made of gold, silver, tin, a platinum group metal, or indium tin oxide. The connection structure of the circuit member described in 1. 21. The circuit member connection structure according to claim 12, wherein at least one of the first and second circuit boards is made of an organic insulating material, glass, or silicon.

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