JP2015195199A - Photocurable conductive material, connection structure and method of producing connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocurable conductive material that is used for connection of a connection object member having an electrode on its surface, suppresses warpage of the connection object member to be able to improve reliability of electric conductivity between electrodes, and prevents occurrence of voids at joint interfaces to be able to improve reliability of connection between the connection object member and a cured product of the conductive material.SOLUTION: A photocurable conductive material according to the present invention is used for connection of a connection object member having an electrode on its surface, and has photocurability. The conductive material comprises conductive particles, photocurable compounds, light cationic polymerization initiators, and photocuring retarders, the photocuring retarders being tertiary amine compounds.

Description

  The present invention relates to a photocurable conductive material containing conductive particles and a curable component having photocurability. The present invention also relates to a connection structure using the photocurable conductive material and a method for manufacturing the connection structure.

  Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In the anisotropic conductive material, conductive particles are dispersed in a binder resin.

  In order to obtain various connection structures, the anisotropic conductive material is, for example, a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)) or a connection between a semiconductor chip and a flexible printed circuit board (COF ( Chip on Film)), connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)), and the like.

  For example, when the electrode of the semiconductor chip and the electrode of the glass substrate are electrically connected by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass substrate. Next, the semiconductor chips are stacked, and heated and pressurized. As a result, the anisotropic conductive material is cured, and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

  As an example of the anisotropic conductive material, Patent Document 1 below discloses a conductive material including a capsule containing a light-emitting component and conductive particles in a resin as an adhesive. The capsule containing the light emitting component and the conductive particles are blended separately.

  Patent Document 2 listed below includes light-reflective conductive particles comprising core particles coated with a metal material and a light-reflective layer formed of light-reflective inorganic particles having a refractive index of 1.52 or more. It is disclosed. The light reflecting layer is disposed on the surface of the core particle. The light reflective conductive particles are used for anisotropic conductive connection of a light emitting element to a wiring board.

  Moreover, the following patent documents 3 and 4 disclose a composition that is not a material used as a conductive material containing conductive particles.

  Patent Document 3 below includes (A) component: epoxy resin, (B) component: aliphatic compound having an epoxy group and a hydroxyl group, and (C) component: an initiator that generates a cationic species by active energy rays. The resin composition which has delayed hardening containing 5 to 45 mass parts of (B) component with respect to 100 mass parts of (A) component is disclosed.

  Patent Document 4 below discloses an adhesive composition containing a cationic polymerizable substance (A), an energy ray cationic polymerization initiator (B), and a cationic polymerization retarder (C).

  Patent Document 5 below discloses an adhesive composition containing (A) an epoxy compound, (B) a photocation generator, and (C) a chain transfer agent having a chain transfer action of cationic polymerization. . The adhesive composition can include conductive particles. Patent Document 5 describes that the adhesive composition may contain a chain ether compound or a cyclic ether compound for the purpose of controlling the curing behavior of the epoxy compound (A). Examples of chain ether compounds or cyclic ether compounds include polyethylene glycols such as diethylene glycol, triethylene glycol, and tetraethylene glycol, and derivatives obtained by functionalizing the terminal hydroxyl groups with ether bonds or ester bonds; ethylene oxide, propylene oxide, cyclohexene oxide, etc. A monofunctional epoxy polymer; a monofunctional or polyfunctional oxetane polymer; a monofunctional or polyfunctional tetrahydrofuran polymer; 12-crown-4-ether, 14- Crown-4-ether, 15-crown-5-ether, 18-crown-6-ether, 21-crown-7-ether, 24-crown-8-ether, 30-crown-7-ether, benzo-18- Crown-6-e Cyclized products of polyethylene glycols such as ter, dibenzo-18-crown-6-ether, tribenzo-18-crown-6-ether; cyclized products of polymers of monofunctional epoxies such as ethylene oxide, propylene oxide, and cyclohexene oxide Is listed.

JP 2010-254788 A JP 2011-86823 A JP 2011-38090 A JP-A-11-181391 JP 2007-100065 A

  In recent years, thinning of various connection target members bonded by a conductive material has progressed. When the connection target member bonded by the conductive material is thin, there is a problem that the connection target member is likely to warp due to bonding or heat. Generation | occurrence | production of the curvature of a connection object member reduces the conduction | electrical_connection reliability between electrodes significantly. In order to suppress warpage, it is desirable to cure the conductive material by photocuring, or to cure the conductive material by thermal curing and photocuring in order to lower the thermosetting temperature.

  However, if the conductive material is cured by photocuring, or if the conductive material is cured by thermal curing and photocuring in order to lower the heat curing temperature, the light is blocked by the electrodes and conductive particles. The conductive material portion that has not been directly irradiated may be insufficiently cured. Insufficient curing not only causes warping of the connection target member but also causes peeling. In particular, curing is likely to be insufficient at a portion where light is blocked by the electrode. This can occur even when the conductive materials described in Patent Documents 1 and 2 are used.

  On the other hand, if the conductive material is irradiated with light from the upper side of the conductive material before the upper connection target member is stacked, it is possible to prevent light from being blocked by the electrode. However, before the upper connection target member is stacked, if the upper connection target member is stacked after irradiating the conductive material with light from the upper side of the conductive material, the curing of the conductive material has considerably progressed. The member to be connected and the cured material of the conductive material may not be sufficiently connected. This can occur even when the conductive materials described in Patent Documents 1 and 2 are used.

  In addition, since the compositions described in Patent Documents 3 and 4 are not conductive materials containing conductive particles, the above problems themselves do not exist.

  In addition, in an adhesive composition using a chain ether compound or a cyclic ether compound as described in Patent Document 5, voids are likely to occur at the adhesion interface, and the adhesiveness may be lowered. In addition, when L / S indicating the width of the line (L) where the electrode is present and the space (S) where the electrode is absent is small, voids are more likely to occur at the adhesive interface, and the adhesiveness is further reduced. There is a problem that it is easy.

  An object of the present invention is to suppress warpage of a connection target member and improve conduction reliability between electrodes when used for connection of a connection target member having an electrode on the surface, and to generate a void at a bonding interface. It is difficult to provide a photo-curable conductive material that can increase the connection reliability between a connection target member and a cured product of the conductive material. Another object of the present invention is to provide a connection structure using the photocurable conductive material and a method for manufacturing the connection structure.

  According to a wide aspect of the present invention, a conductive material that is used for connection of a connection target member having an electrode on its surface and has photocurability, a conductive particle, a photocurable compound, a photocationic polymerization initiator, A photocurable conductive material comprising a photocuring retarder, wherein the photocuring retarder is a tertiary amine compound.

  The tertiary amine compound is preferably a compound having a triazine skeleton. The tertiary amine compound preferably has a cationic polymerizable group. The cationically polymerizable group is preferably an epoxy group.

  In a specific aspect of the photocurable conductive material according to the present invention, the photocationic polymerization initiator is a photocationic polymerization initiator that generates an acid by light irradiation, and the photocuring retarder is a photocationic polymerization. The acid generated from the initiator can be captured.

  The photocurable conductive material according to the present invention connects a first connection target member having a first electrode on the surface and a second connection target member having a second electrode on the surface, and the first connection target member has the first electrode. The electrode is suitably used to obtain a connection structure by electrically connecting the second electrode and the second electrode, and the photocurable conductive material is disposed on the surface of the first connection target member. Later, first photoirradiation is performed on the photocurable conductive material from the side opposite to the first connection target member side, and then the conductive property is provided between the first electrode and the second electrode. The second connection target member is disposed on the surface opposite to the first connection target member side of the photocurable conductive material subjected to the first light irradiation so that the particles are positioned, Of the second light irradiation and heat application to the photocurable conductive material, when or after the two connection target members are arranged One is performed Kutomo, through the steps photocurable conductive material to form a cured product obtained by curing, is preferably used to obtain the connection structure.

  The photocurable conductive material according to the present invention is (1) the connection structure having undergone a step of forming a cured product obtained by curing the photocurable conductive material by second light irradiation to the photocurable conductive material. The connection structure is obtained through a step of forming a cured product obtained by applying heat to the photocurable conductive material and forming a cured product obtained by curing the photocurable conductive material. (3) Curing in which the photocurable conductive material is cured by the second light irradiation and the photocurable conductive material being heated. It is also suitably used for obtaining the connection structure through a step of forming an object.

  In a specific aspect of the photocurable conductive material according to the present invention, the photocurable conductive material is a conductive material having photocurability and thermosetting, and includes a thermosetting compound and a thermosetting agent. .

  According to a wide aspect of the present invention, a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, and the A connection portion that connects the second connection target member, and the connection portion is formed by curing the photocurable conductive material described above, and the first electrode and the second electrode A connection structure is provided in which an electrode is electrically connected by the conductive particles.

  According to the wide aspect of the present invention, the first connection object member having the first electrode on the surface and the second connection having the second electrode on the surface using the above-described photocurable conductive material. A step of disposing the photocurable conductive material on the surface of the first connection target member using the target member; and the photocurable conductivity disposed on the surface of the first connection target member. In the material, the conductive particles are positioned between the first electrode and the second electrode, and the step of performing the first light irradiation from the side opposite to the first connection target member side. And disposing the second connection target member on the surface opposite to the first connection target member side of the photocurable conductive material subjected to the first light irradiation, and the second Of the second light irradiation and heat application to the photocurable conductive material during or after the arrangement of the connection target member A step of performing at least one, forming a connection portion connecting the first connection target member and the second connection target member with a cured product of the photocurable conductive material, and A method for manufacturing a connection structure is provided in which the first electrode and the second electrode are electrically connected by the conductive particles.

  In the method for manufacturing a connection structure according to the present invention, the second light irradiation step includes (1) second light irradiation to the photocurable conductive material during or after the second connection target member is disposed. It is preferable that the second light irradiation step is performed, and (2) a heat application step for applying heat to the photocurable conductive material during or after the second connection target member is arranged. (3) Second time of irradiating the photocurable conductive material with a second light and applying heat to the photocurable conductive material during or after the second connection target member is arranged. It is also preferable to be a light irradiation and heat application step.

  The photocurable conductive material according to the present invention is a photocurable conductive material, and includes conductive particles, a photocurable compound, a photocationic polymerization initiator, and a photocuring retarder. Since the curing retarder is a tertiary amine compound, when used for connection of a connection target member having an electrode on the surface, the warpage of the connection target member can be suppressed and the conduction reliability between the electrodes can be improved, and It is possible to increase the reliability of connection between the connection target member and the cured material of the conductive material by making it difficult for voids to form at the bonding interface.

FIG. 1 is a cross-sectional view schematically showing a connection structure using a photocurable conductive material according to an embodiment of the present invention. 2A to 2D are cross-sectional views for explaining an example of a method for manufacturing a connection structure using a photocurable conductive material according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles used in the photocurable conductive material according to one embodiment of the present invention. FIG. 4 is a cross-sectional view showing conductive particles used in a photocurable conductive material according to another embodiment of the present invention.

  Details of the present invention will be described below.

  The photocurable conductive material according to the present invention is a conductive material that is used for connection of a connection target member having electrodes on the surface and has photocurability. The photocurable conductive material according to the present invention includes conductive particles, a photocurable compound, a photocationic polymerization initiator, and a photocuring retarder. The photocuring retarder delays the curing rate of the conductive material after irradiation with light, compared to the case where no photocuring retarder is used. In the photocurable conductive material according to the present invention, the photocuring retarder is a tertiary amine compound.

  By adopting the above-described configuration in the photocurable conductive material according to the present invention, when used for connection of a connection target member having an electrode on the surface, the warpage of the connection target member is suppressed and the conduction reliability between the electrodes is increased. be able to. Furthermore, by adopting the above-described configuration in the photocurable conductive material according to the present invention, in particular, the photocuring retarder is a tertiary amine compound. The connection reliability with the hardened | cured material of an electroconductive material can be improved. In the present invention, even if the L / S indicating the width of the line (L) where the electrode is present and the space (S) where the electrode is not present is small, it is difficult to generate a void at the joint interface, and the connection target member and the conductive material Connection reliability with the cured product can be improved.

  In the present invention, even if the photocurable conductive material is irradiated with light, the curing does not proceed rapidly due to the influence of the photocuring retarder.For example, even before the upper connection target member is laminated, The conductive material can be irradiated with light from the upper side of the conductive material, and a connection structure excellent in connection reliability can be obtained even when this light irradiation is performed. Also, sufficient adhesion can be secured when the upper connection target members are stacked. Further, when the upper connection target member is stacked, the component excluding the conductive particles between the electrode and the conductive particles is highly excluded. Moreover, generation of voids can be suppressed in the obtained connection structure. In addition, if the conductive material is irradiated with light from the upper side of the conductive material before the upper connection target member is laminated, the light can be prevented from being blocked by the electrode, and the conductive material can be directly irradiated with light uniformly. Is possible. By directly irradiating the conductive material with light directly, it is possible to prevent the curing rate of the cured material of the conductive material from being partially different. For this reason, the curvature of the connection object member connected by the hardened | cured material of the electrically conductive material can be suppressed. Even if the connection target member is thin, warping can be sufficiently suppressed. By suppressing the warpage of the connection object member, the conduction reliability between the electrodes can be increased.

  In the present invention, the conductive material can be cured only by photocuring, or the conductive material can be cured by thermal curing and photocuring. By performing photocuring, when the conductive material is thermally cured, the thermal curing temperature for sufficiently curing the conductive material can be lowered. By lowering the thermosetting temperature, it is possible to suppress thermal degradation of the connection target member. Furthermore, by reducing the thermosetting temperature, it is possible to effectively suppress the warpage of the connection target member due to heat.

  In this invention, after irradiating light to a conductive material from the upper side of a conductive material, hardening of the conductive material at the time of arrangement | positioning of an upper connection object member is suppressed. Thus, even if the upper connection target member is stacked after the conductive material is irradiated with light from the upper side of the conductive material, the upper connection target member and the cured material of the conductive material can be sufficiently connected.

  The photocurable conductive material according to the present invention connects the first connection target member having the first electrode on the surface and the second connection target member having the second electrode on the surface, and the first connection member. This electrode is suitably used for obtaining a connection structure by electrically connecting the second electrode and the second electrode.

  Moreover, regarding the photocurable conductive material according to the present invention, after the photocurable conductive material is disposed on the surface of the first connection target member, from the side opposite to the first connection target member side. The first light irradiation is performed on the photocurable conductive material, and then the first light irradiation is performed such that the conductive particles are positioned between the first electrode and the second electrode. When the second connection target member is disposed on the surface of the photocurable conductive material opposite to the first connection target member side or after the second connection target member is disposed, the second light is applied to the photocurable conductive material. At least one of irradiation and application of heat is performed, and it is suitably used for obtaining the connection structure through a step of forming a cured product obtained by curing the photocurable conductive material. By obtaining the connection structure through such steps, a connection structure having high conduction reliability between the electrodes and high connection reliability between the connection target member and the cured conductive material can be obtained.

  In this case, the photocurable conductive material according to the present invention is (1) subjected to a process of forming a cured product obtained by curing the photocurable conductive material by applying a second light irradiation to the photocurable conductive material. The connection structure is preferably used to obtain the connection structure. (2) The connection is performed through a step of forming a cured product obtained by curing the photocurable conductive material by applying heat to the photocurable conductive material. It is also preferably used for obtaining a structure, and (3) the photocurable conductive material is subjected to the second light irradiation and the photocurable conductive material is applied with heat, so that the photocurable conductive material is used. It is also suitably used for obtaining the above connection structure through a step of forming a cured product.

  The photocationic polymerization initiator is preferably a photocationic polymerization initiator that generates an acid upon irradiation with light. The photocuring retarder is preferably capable of capturing an acid generated from the photocationic polymerization initiator. It is preferable that a part of the acid is generated from the cationic curing initiator by the first light irradiation, and an acid is generated from the cationic photopolymerization initiator by the second light irradiation. It is preferable not to generate all the acid from the cationic curing initiator by the first light irradiation. In this case, when the conductive material is irradiated with light from the upper side of the conductive material before the upper connection target member is laminated, if the acid is generated from the photocationic polymerization initiator, the acid is effective due to the photocuring retarder. Captured. For this reason, even if it irradiates light to a conductive material from the upper side of a conductive material, the raise of the hardening degree of a photocurable conductive material can be suppressed effectively before lamination | stacking of the upper connection object member. In the photocurable conductive material according to the present invention, it is preferable that the photocuring retarder cannot capture part or all of the acid generated from the photocationic polymerization initiator by the second light irradiation. . In this case, the photocurable conductive material can be effectively cured by the second light irradiation. In the present invention, it is preferable that the action of the photocuring retarder is expressed after the first light irradiation, and the action of the photocuring retarder is not expressed after the second light irradiation than after the first light irradiation.

  All the acids may be generated by the first light irradiation. In this case, the first connection target member of the photocurable conductive material that has been subjected to the first light irradiation so that the conductive particles are positioned between the first electrode and the second electrode. When the second connection object member is disposed on the surface opposite to the side or after the second connection target member is disposed, the second light irradiation is not performed on the photocurable conductive material, and heat is applied to the photocurable conductive material. It is possible to carry out only curing by heat.

  The photocurable conductive material according to the present invention is a conductive material having photocurability and thermosetting, and preferably contains a thermosetting compound and a thermosetting agent. In this case, the photocurable conductive material can be effectively cured by applying heat to the photocurable conductive material.

  Moreover, regarding the photocurable conductive material according to the present invention, after the photocurable conductive material is disposed on the surface of the first connection target member, from the side opposite to the first connection target member side. The first light irradiation is performed on the photocurable conductive material, and then the first light irradiation is performed such that the conductive particles are positioned between the first electrode and the second electrode. When the second connection target member is disposed on the surface of the photocurable conductive material opposite to the first connection target member side and the second connection target member is disposed or after the second connection target member is disposed. The connection is performed through a step of forming a cured product in which the photocurable conductive material is cured by applying a second light irradiation to the photocurable conductive material and applying heat to the photocurable conductive material. It is preferably used for obtaining a structure. By obtaining a connection structure through such processes, a connection structure having higher conduction reliability between the electrodes and further higher connection reliability between the connection target member and the cured conductive material is obtained. Can do.

  The photocurable conductive material is preferably a circuit connection material. The photocurable conductive material is preferably an anisotropic conductive material. The anisotropic conductive material includes a conductive material for conducting between the upper and lower electrodes.

  The photocurable conductive material can be used as a conductive paste and a conductive film. When the photocurable conductive material is a conductive film, a film not containing conductive particles may be laminated on the conductive film containing the conductive particles.

  From the viewpoint of suppressing the generation of voids at the connection portions in the connection structure and further improving the conduction reliability, the photocurable conductive material is preferably a conductive paste. The photocurable conductive material is preferably a conductive paste and is applied to the upper surface of the connection target member in a paste state.

  Next, a connection structure using a photocurable conductive material according to an embodiment of the present invention will be specifically described with reference to FIG.

  FIG. 1 is a cross-sectional view schematically showing a connection structure using a photocurable conductive material according to an embodiment of the present invention. The connection structure 1 shown in FIG. 1 includes a first connection target member 2 having a first electrode 2a on the surface, a second connection target member 3 having a second electrode 3a on the surface, and a first connection. A connecting portion 4 that connects the target member 2 and the second connection target member 3 is provided. The connection part 4 contains the hardened | cured material 11 of a photocuring component.

  The 1st electrode 2a and the 2nd electrode 3a are electrically connected by the electroconductive particle 21 (The electroconductive particle 21 shown in FIG. 3 mentioned later). The connection part 4 irradiates the photocurable conductive material containing the conductive particles 21, the photocurable compound, the photocationic polymerization initiator, and the photocuring retarder that is a tertiary amine compound with light, and It is formed by curing a photocurable conductive material.

  Specifically, the connection structure 1 shown in FIG. 1 can be obtained as follows, for example, through the states shown in FIGS. Here, the photo-curing conductive material includes a photo-curing compound, a photo-cationic polymerization initiator, and a photo-curing retarder that is a tertiary amine compound, and has photo-curing properties and thermosetting properties. Conductive material (photo-curable and thermosetting conductive material) is used. In the following description, a photocurable compound, a photocationic polymerization initiator, and a photocurable retarder that is a tertiary amine compound may be referred to as a photocurable component. In addition, you may use the photocurable conductive material which does not have thermosetting but has only photocurable. The photocurable compound not only acts as a photocurable compound, but may also act as a thermosetting compound, and may be a light and thermosetting compound.

  As shown in FIG. 2A, a first connection target member 2 having a first electrode 2a on the surface (upper surface) is prepared. In addition, a photocurable conductive material including a plurality of conductive particles 21 and a photocurable component is prepared. Next, 4 A of photocurable conductive material layers are arrange | positioned on the surface by the side of the 1st electrode 2a of the 1st connection object member 2 using the said photocurable conductive material. At this time, it is preferable that one or a plurality of conductive particles 21 be disposed on the first electrode 2a. Here, since the conductive paste is used as the photocurable conductive material, the conductive paste is arranged by applying the conductive paste. The photocurable conductive material layer 4A is a conductive paste layer.

  Next, before the upper second connection target member 3 is disposed, the photocurable conductive material layer 4A is irradiated with light from the upper side of the photocurable conductive material layer 4A (first light irradiation step). That is, before the second connection target member 3 is arranged, the photocurable conductive material layer 4A is irradiated with the first light from the side opposite to the first connection target member 2 side of the photocurable conductive material layer 4A. Do. In the present embodiment, since the first light irradiation is performed before the second connection target member 3 is arranged, the light is not blocked by the second electrode 3 a in the second connection target member 3. For this reason, light can be made to reach the entire region of the photocurable conductive material layer 4A relatively uniformly. On the other hand, when the first light irradiation is performed after the second connection target member 3 is disposed, the light is blocked by the second electrode 3a, and the light is not directly irradiated to the photocurable conductive material layer 4A. Exists. If the first light irradiation is performed before the second connection target member 3 is arranged, there is a region of the photocurable conductive material layer 4 </ b> A where the light is blocked by the conductive particles 21, but per one of the regions. The size is smaller than the size of the region of the photocurable conductive material layer 4A where light is blocked by the second electrode 3a. The influence of the region of the photocurable conductive material layer 4A where light is blocked by the conductive particles 21 is smaller than the influence of the region of the photocurable conductive material layer 4A where light is blocked by the second electrode 3a.

  As shown in FIGS. 2 (a) and 2 (b), by the first light irradiation, the photocurable conductive material layer 4A becomes the photocurable conductive material layer 4B subjected to the first light irradiation. After the first light irradiation, the curing of the photocurable conductive material layer 4B does not proceed rapidly due to the influence of the photocuring retarder, and the curing rate of the photocurable conductive material layer 4B is slow. As a result, curing is suppressed in the photocurable conductive material layer 4B.

  Next, as shown in FIG. 2C, the second light irradiation is performed on the surface opposite to the first connection target member 2 side of the photocurable conductive material layer 4B subjected to the first light irradiation. The 2nd connection object member 3 which has the electrode 3a on the surface is arrange | positioned from the 2nd electrode 3a side. That is, the photocurable conductive material layer 4 </ b> B is disposed between the first connection target member 2 and the second connection target member 3. Moreover, the 2nd connection object member 3 is arrange | positioned so that the 1st electrode 2a and the 2nd electrode 3a may oppose. At this time, the photocurable conductive material layer 4B is disposed so that the conductive particles 21 are located between the first electrode 2a and the second electrode 3a.

  The second light irradiation is performed on the photocurable conductive material layer 4B subjected to the first light irradiation at the time of or after the second connection target member 3 is disposed (second light irradiation process). Further, heat is applied to the photocurable conductive material layer 4B during or after the second connection target member 3 is disposed (first heat application step). Preferably, heat is applied by the thermocompression bonding head 51. It is preferable to apply heat to the photocurable conductive material layer 4B by thermocompression bonding the first connection target member 2 and the second connection target member 3. When heat is applied, the second light irradiation may not be performed. As a result of progress of curing of the photocurable conductive material layer 4B by the second light irradiation, preferably by the second light irradiation and the application of the first heat, or by the application of the first heat, FIG. As shown in d), a photo-curing conductive material layer 4C that has been cured is formed. At this point, the connecting portion 4 may be formed.

  A step of performing at least one of the second light irradiation and the application of heat to the photocurable conductive material may be performed during or after the second connection target member is arranged. The second light irradiation step may be (1) a second light irradiation step of performing second light irradiation on the photocurable conductive material at the time of or after the second connection target member is disposed. Preferably, (2) it is also preferably a heat application step of applying heat to the photocurable conductive material at the time of or after the second connection target member is arranged, and (3) the second connection target. It may also be a second light irradiation and heat application step in which a second light irradiation is performed on the photocurable conductive material and a heat is applied to the photocurable conductive material during or after the arrangement of the members. preferable.

  Preferably, after the application of the first heat, or after the application of the second light irradiation and the first heat, the application of the second heat to the photocurable conductive material layer 4C. Then, the connection portion 4 is formed (second heat application step), and more preferably, the second heat is applied to the photocurable conductive material layer 4C after the second light irradiation and the first heat application. The connection part 4 is formed by providing (2nd heat provision process).

  As a result, the connection structure 1 shown in FIG. 1 is obtained.

  The light source used at the time of 1st light irradiation and 2nd light irradiation is not specifically limited. Examples of the light source include a light source having a sufficient light emission distribution at a wavelength of 420 nm or less, a light source having strong light emission at a specific wavelength of 420 nm or less, and the like. Specific examples of the light source having a sufficient light emission distribution at a wavelength of 420 nm or less include, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, and a metal halide lamp. Can be mentioned. Moreover, an LED lamp etc. are mentioned as a specific example of the light source which has strong light emission in the specific wavelength of 420 nm or less. Among these, an LED lamp is preferable. When an LED lamp is used, the irradiation object itself generates very little heat, and excessive thermal deterioration of the photocurable conductive material due to heat generation can be prevented.

Light irradiation amount in the first light irradiation is preferably 50 to 500 mJ / cm ^2, more preferably about 100 mJ / cm ² or more, more preferably 150 mJ / cm ² or more, more preferably 400 mJ / cm ² or less, More preferably, it is 300 mJ / cm ² or less.

In order to cure the photocurable conductive material layer by the second light irradiation, the light irradiation amount for appropriately curing the photocurable conductive material layer is preferably about 300 to 1000 mJ / cm ² . more preferably 400 mJ / cm ² or more, more preferably 500 mJ / cm ² or more, more preferably 900 mJ / cm ² or less, more preferably 800 mJ / cm ² or less.

  From the viewpoint of suppressing the progress of curing by the first light irradiation and effectively proceeding the curing by the second light irradiation, the light irradiation intensity in the first light irradiation is the light irradiation intensity in the second light irradiation. Is preferably smaller. The light irradiation intensity in the first light irradiation is preferably 1/2 or less, more preferably 1/3 or less of the light irradiation intensity in the second light irradiation.

Photocurable conductive material 60 seconds after the viscosity η1 of the photocurable conductive material before the first light irradiation and ultraviolet irradiation with a wavelength of 365 nm are applied so that the light irradiation amount is 150 mJ / cm ^2. When the viscosity η2 of the material is measured, the ratio of the viscosity η2 to the viscosity η1 (η2 / η1) is preferably 1.5 or less, more preferably 1.3 or less. The ratio (η2 / η1) is generally 0.5 or more, preferably 0.8 or more, more preferably 0.9 or more, and further preferably 1 or more.

  Note that the second light irradiation is performed at the time of or after the placement of the second connection target member, and may be performed at the time of placement or after the placement. However, it is more preferable that the second light irradiation is performed after the arrangement. In addition, the second light irradiation and the application of the first heat may be performed simultaneously, may be performed separately, or the first heat may be applied after the second light irradiation, The second light irradiation may be performed after the application of the first heat. It is preferable that the second light irradiation and the application of the first heat are performed simultaneously.

  In the case of curing by applying heat to the photocurable conductive material, the heating temperature for appropriately curing the photocurable conductive material layer is preferably 80 ° C or higher, more preferably 100 ° C or higher, preferably Is 150 ° C. or lower, more preferably 130 ° C. or lower.

  When the application of the first heat and the application of the second heat are performed, the heating temperature in the application of the first heat is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, preferably 150 ° C or lower, more preferably 130 ° C or lower. The heating temperature in the application of the second heat is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, preferably 150 ° C. or lower, more preferably 130 ° C. or lower.

  The application of the first heat is preferably performed during or after the placement of the second connection target member, may be performed during the placement, or may be performed after the placement. However, the application of the first heat is more preferably performed at the time of arrangement.

  In the manufacturing method of the connection structure 1, even if the first light irradiation is performed on the photocurable conductive material layer 4 </ b> A, the curing does not proceed rapidly by employing the photocuring retarder. Before the second connection target member 3 is arranged, the photocurable conductive material layer 4A can be irradiated with light from the side opposite to the first connection target member 2 side of the photocurable conductive material layer 4A. If the first light irradiation is performed on the photocurable conductive material layer 4A from the side opposite to the first connection target member 2 side of the photocurable conductive material layer 4A before the arrangement of the second connection target member 3, It is possible to prevent light from being blocked by the second electrode 3a, and it is possible to directly irradiate light uniformly on the photocurable conductive material layer 4A. By directly irradiating the photo-curing conductive material layer 4A directly with light, it is possible to prevent the curing rate of the cured product (connection portion 4) of the photo-curing conductive material from being partially different. For this reason, the curvature of the 1st, 2nd connection object members 2 and 3 connected by the hardened | cured material (connection part) of a photocurable conductive material can be suppressed. Even if the first and second connection target members 2 and 3 are thin, warping can be sufficiently suppressed. Further, before the second connection target member 3 is arranged, the photocurable conductive material layer 4A is irradiated with the first light from the side opposite to the first connection target member 2 side of the photocurable conductive material layer 4A. After that, excessive curing of the photocurable conductive material layer 4B at the time of arrangement of the second connection target member 3 is suppressed. Thus, after the first light irradiation is performed on the photocurable conductive material layer 4A from the side opposite to the first connection target member 2 side of the photocurable conductive material layer 4A, the second connection target member 3 is provided. Even if it arrange | positions, the 2nd connection object member 3 and the hardened | cured material (connection part 4) of photocurable conductive material can fully be connected. Furthermore, since the photocuring retarder that is a tertiary amine compound is used in particular, it is possible to make it difficult for voids to occur at the bonding interface as compared with the case of using a photocuring retarder that is not a tertiary amine compound. By suppressing the generation of voids present at the bonding interface, the connection reliability between the connection target member and the cured material of the conductive material can be increased.

  Hereinafter, other details of the conductive particles, the photocurable conductive material, and the connection structure will be described.

(Conductive particles)
In FIG. 3, the electroconductive particle 21 used for the photocurable conductive material which concerns on one Embodiment of this invention is shown with sectional drawing.

  The conductive particles 21 electrically connect the first and second electrodes 2 a and 3 a of the first and second connection target members 2 and 3. The conductive particle 21 includes a base particle 31 and a conductive portion 32 disposed on the surface of the base particle 31. The conductive part 32 is a conductive layer. An insulating substance may be disposed on the conductive surface of the conductive particles. An insulating material may be disposed on the outer surface of the conductive portion. The insulating substance is excluded from between the conductive layer and the electrode when the connection target member is connected. The conductive particles may have protrusions on the conductive surface. The conductive particles may have protrusions on the outer surface of the conductive part.

  Moreover, although the electroconductive particle 21 has the base particle 31, the electroconductive particle may be formed with the electroconductive material as a whole. The entirety of the conductive particles may be a conductive portion. Moreover, although the electroconductive particle 21 has the single-layer electroconductive part 32 (electroconductive layer), the electroconductive particle may have a multilayer conductive layer.

  FIG. 4 is a sectional view showing a conductive particle composite used in a photocurable conductive material according to another embodiment of the present invention.

  The conductive particle composite body 22 illustrated in FIG. 4 includes the conductive particles 21 and the photocuring retarder 33 attached to the surface of the conductive particles 21. Thus, the photocuring retarder 33 may be attached to the surface of the conductive particles 21. The conductive particle composite 22 in which the photocuring retarder 33 is attached to the surface of the conductive particles 21 may be used. When this conductive particle composite 22 is used, it is difficult for the photo-curing retarder to lower the adhesiveness of the photo-curable conductive material, and the connection reliability is further enhanced in the connection structure. In addition, since the photo-setting retarder 33 is attached to the surface of the conductive particles 21, the compounding components excluding the conductive particles between the electrodes and the conductive particles are eliminated at the time of conductive connection. The conduction reliability can be improved.

  Examples of the substrate particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. The substrate particles are preferably substrate particles excluding metal particles, and more preferably resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles.

  The substrate particles are preferably resin particles formed of a resin. When connecting between electrodes, after arrange | positioning the said electroconductive particle between electrodes, generally the said electroconductive particle is compressed. When the substrate particles are resin particles, the conductive particles are easily deformed by compression, and the contact area between the conductive particles and the electrode is increased. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  Various organic materials are suitably used as the material for the resin particles. Examples of the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polyalkylene terephthalate and polysulfone. , Polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene oxide, Polyacetal, polyimide, polyamideimide, polyetherether Tons, polyethersulfone, and polymers such as obtained by a variety of polymerizable monomer having an ethylenically unsaturated group is polymerized with one or more thereof. Design and synthesis of resin particles with any compression properties suitable for photo-curing conductive materials by polymerizing one or more of various polymerizable monomers having an ethylenically unsaturated group Is possible. Further, since the hardness of the base particles can be easily controlled within a suitable range, the material of the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having a plurality of ethylenically unsaturated groups. It is preferable that

  When the resin particles are obtained by polymerizing a monomer having an ethylenically unsaturated group, the monomer having the ethylenically unsaturated group may be a non-crosslinkable monomer or a crosslinkable monomer. And a polymer.

  Examples of the non-crosslinkable monomer include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl ( Alkyl (meth) acrylates such as meth) acrylate and isobornyl (meth) acrylate; oxygen such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate (Meth) acrylates; nitrile-containing monomers such as (meth) acrylonitrile; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether; vinyl acids such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate Esters; Unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; Halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride and chlorostyrene Is mentioned.

  Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipenta Erythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylates such as acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) cyanure And silane-containing monomers such as triallyl trimellitate, divinylbenzene, diallyl phthalate, diallylacrylamide, diallyl ether, γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane It is done.

  The resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of polymerization by swelling a monomer together with a radical polymerization initiator using non-crosslinked seed particles.

  In the case where the substrate particles are inorganic particles or organic-inorganic hybrid particles excluding metal particles, examples of the inorganic material that is a material of the substrate particles include silica and carbon black. The particles formed from the silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, firing may be performed as necessary. The particle | grains obtained by performing are mentioned. Examples of the organic / inorganic hybrid particles include organic / inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

  When the substrate particles are metal particles, examples of the metal that is a material of the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, the substrate particles are preferably not metal particles.

  The average particle diameter of the substrate particles is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, still more preferably 1.5 μm or more, particularly preferably 2 μm or more, preferably 1000 μm or less. More preferably, it is 500 μm or less, more preferably 300 μm or less, still more preferably 100 μm or less, still more preferably 50 μm or less, still more preferably 30 μm or less, particularly preferably 5 μm or less, and most preferably 3 μm or less. When the average particle diameter of the base particles is equal to or greater than the above lower limit, the contact area between the conductive particles and the electrode is increased, and thus the conduction reliability between the electrodes is further increased, and the connection is made through the conductive particles. The connection resistance between the formed electrodes is further reduced. Furthermore, when forming a conductive part on the surface of a base particle by electroless plating, it becomes difficult to aggregate and it becomes difficult to form the aggregated conductive particles. When the average particle diameter of the substrate particles is not more than the above upper limit, the conductive particles are easily compressed, the connection resistance between the electrodes is further reduced, and the interval between the electrodes is further narrowed.

  The average particle diameter of the substrate particles is particularly preferably 0.1 μm or more and 5 μm or less. When the average particle diameter of the substrate particles is in the range of 0.1 to 5 μm, even when the distance between the electrodes is small and the thickness of the conductive portion is increased, the small conductive particles can be obtained. From the viewpoint of obtaining even smaller conductive particles even when the distance between the electrodes is further reduced or the thickness of the conductive portion is increased, the average particle diameter of the base particles is preferably 0.00. It is 5 μm or more, more preferably 2 μm or more, and preferably 3 μm or less. From the viewpoint of further improving the connection reliability and the conduction reliability, the average particle diameter of the base particles is preferably 2.6 μm or more.

  The average particle diameter of the substrate particles indicates a number average particle diameter. The average particle diameter can be measured using, for example, a Coulter counter (manufactured by Beckman Coulter).

  The thickness of the conductive part is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more, particularly preferably 50 nm or more, preferably 1000 nm or less, more preferably 800 nm or less, still more preferably 500 nm or less, particularly preferably 400 nm or less, most preferably 300 nm or less. When there are a plurality of conductive portions, the thickness of the conductive portion is the thickness of the entire plurality of conductive portions. When the thickness of the conductive part is equal to or greater than the lower limit, the conductivity of the conductive particles is further improved. When the thickness of the conductive part is not more than the above upper limit, the difference in the coefficient of thermal expansion between the base particle and the conductive part becomes small, and the conductive part becomes difficult to peel from the base particle.

  Examples of a method for forming the conductive part on the surface of the substrate particle include a method for forming the conductive part by electroless plating and a method for forming the conductive part by electroplating.

  The conductive part preferably contains a metal. The metal that is the material of the conductive part is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, tungsten, molybdenum and cadmium, and alloys thereof. Is mentioned. Further, tin-doped indium oxide (ITO) may be used as the metal. As for the said metal, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of further improving the reliability of conduction between the electrodes, the average particle size of the conductive particles is preferably 1.5 μm or more, more preferably 2.5 μm or more, preferably 10 μm or less, more preferably 5 μm or less. is there. From the viewpoint of further improving connection reliability and conduction reliability, the average particle diameter of the conductive particles is preferably 2.8 μm or more.

  The average particle diameter of the conductive particles indicates a number average particle diameter. The average particle diameter is determined using a particle size distribution measuring device or the like.

  The conductive particles preferably have a plurality of protrusions on the conductive surface. In addition, since the core substance is embedded in the conductive portion, a protrusion can be easily formed on the outer surface of the conductive portion. The protrusion increases both the connection reliability and the conduction reliability. An oxide film is often formed on the surface of the electrode connected by the conductive particles. When conductive particles having protrusions are used, the oxide film is effectively excluded by the protrusions by placing the conductive particles between the electrodes and pressing them. For this reason, an electrode and the said electroconductive particle contact more reliably, and the connection resistance between electrodes becomes still lower. Furthermore, the projection effectively eliminates the compounding component (binder resin) excluding the conductive particles between the conductive particles and the electrode. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  As a method for forming protrusions on the surface of the conductive particles, a conventionally known method can be employed. A method of forming a conductive part by electroless plating after attaching a core substance to the surface of the base particle, and a method of forming a conductive part by electroless plating on the surface of the base particle, attaching a core substance, For example, a method of forming a conductive portion by electroless plating. As another method for forming the protrusion, a first conductive part is formed on the surface of the base particle, and then a core substance is disposed on the first conductive part, and then the second conductive part. , A method of adding a core substance in the middle of forming a conductive part on the surface of the base particle, and a method of depositing a core substance in the middle of forming a conductive part on the surface of the base particle Etc.

  Examples of the material of the core substance include a conductive substance and a non-conductive substance. Examples of the conductive substance include metals, metal oxides, conductive non-metals such as graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Examples of the nonconductive material include silica, alumina, and zirconia. Among them, metal is preferable because conductivity can be increased and connection resistance can be effectively reduced. The core substance is preferably metal particles.

  The conductive particles preferably include an insulating material disposed on the surface of the conductive particles. In this case, when the conductive particles are used for connection between electrodes, a short circuit between adjacent electrodes can be prevented. Specifically, when a plurality of the conductive particles are in contact with each other, an insulating material is present between the plurality of conductive particles, so that it is possible to prevent a short circuit between electrodes adjacent in the lateral direction instead of between the upper and lower electrodes. Note that the insulating material between the conductive layer and the electrode can be easily removed by pressurizing the conductive particles with the two electrodes when connecting the electrodes. The refractive index of the insulating material may be less than 1.6.

  The insulating substance is preferably an insulating particle because the insulating substance can be more easily removed when the electrodes are pressed.

  The material of the insulating substance is preferably an organic substance or an organic-inorganic hybrid substance. That is, the insulating material (insulating particles and the like) is preferably formed of an organic material or an organic-inorganic hybrid material.

  In 100% by weight of the photocurable conductive material, the content of the conductive particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, still more preferably 1% by weight or more, and particularly preferably 5%. % By weight or more, preferably 80% by weight or less, more preferably 40% by weight or less, still more preferably 30% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% by weight or less. When the content of the conductive particles is not less than the above lower limit and not more than the above upper limit, the conduction reliability between the electrodes is further enhanced.

(Photocurable component)
The photocurable conductive material has photocurability. The photocurable conductive material includes a curable compound, a photocationic polymerization initiator, and a photocuring retarder. The said curable compound contains a photocurable compound (compound curable by irradiation of light). The photocurable conductive material preferably has photocurability and thermosetting. The photocurable conductive material includes a photocurable compound (a compound that can be cured by light irradiation), a cationic photopolymerization initiator, a photocuring retarder, and a thermosetting compound (a compound that can be cured by application of heat). ) And a thermosetting agent. The photocurable compound (compound curable by light irradiation) may be a light and thermosetting compound (compound curable by light irradiation and heat application). The photocationic polymerization initiator may be a light and thermal cationic polymerization initiator.

  The photocurable conductive material preferably has photocurability and thermosetting. In this case, for example, the photocurable conductive material can be cured more favorably by applying heat, and the degree of cure of the cured product of the photocurable conductive material can be effectively increased.

  The photocurable conductive material according to the present invention is preferably used after being cured by applying heat or applying second light and applying heat after the first light irradiation. It is more preferable that the second light irradiation and the heat application be performed after the light irradiation to be cured and used. Thus, the effect of the present invention can be obtained more effectively by curing the photocurable conductive material.

  The method for dispersing the conductive particles in the photocurable component is not particularly limited, and a conventionally known dispersion method can be used.

  In 100% by weight of the photocurable conductive material, the content of the components excluding the conductive particles is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, preferably 90.98. % By weight or less. When the content of the component excluding the conductive particles is not less than the above lower limit and not more than the above upper limit, the conductive particles are efficiently arranged between the electrodes, and the conduction reliability between the electrodes is further enhanced.

Photocurable compound:
The photocurable conductive material contains a photocurable compound so as to be cured by irradiation with light.

  The photocurable compound is not particularly limited, and examples thereof include a photocurable compound having a (meth) acryloyl group and a photocurable compound having a cyclic ether group.

  The photocurable compound is preferably a photocurable compound having a (meth) acryloyl group. By using the photocurable compound having a (meth) acryloyl group, the conduction reliability between the electrodes is further enhanced. From the viewpoint of effectively increasing the conduction reliability between the electrodes, the photocurable compound preferably has one or two (meth) acryloyl groups.

  The photocurable compound having the (meth) acryloyl group has no epoxy group and thiirane group, and has a (meth) acryloyl group, and has an epoxy group or thiirane group, and ( The photocurable compound which has a (meth) acryloyl group is mentioned.

  As a photocurable compound having the above (meth) acryloyl group, an ester compound obtained by reacting a compound having (meth) acrylic acid and a hydroxyl group, an epoxy obtained by reacting (meth) acrylic acid and an epoxy compound. (Meth) acrylate or urethane (meth) acrylate obtained by reacting a (meth) acrylic acid derivative having a hydroxyl group with isocyanate is preferably used. The “(meth) acryloyl group” refers to an acryloyl group and a methacryloyl group. The “(meth) acryl” refers to acryl and methacryl. The “(meth) acrylate” refers to acrylate and methacrylate.

  The ester compound obtained by making the said (meth) acrylic acid and the compound which has a hydroxyl group react is not specifically limited. As the ester compound, any of a monofunctional ester compound, a bifunctional ester compound, and a trifunctional or higher functional ester compound can be used.

  The photocurable compound having the epoxy group or thiirane group and having a (meth) acryloyl group is a part of the epoxy group or part of thiirane of the compound having two or more epoxy groups or two or more thiirane groups. It is preferable that it is a photocurable compound obtained by converting a group into a (meth) acryloyl group. Such a photocurable compound is a partially (meth) acrylated epoxy compound or a partially (meth) acrylated episulfide compound.

  The photocurable compound is preferably a reaction product of a compound having two or more epoxy groups or two or more thiirane groups and (meth) acrylic acid. This reaction product is obtained by reacting a compound having two or more epoxy groups or two or more thiirane groups with (meth) acrylic acid in the presence of a catalyst according to a conventional method.

  Examples of the partially (meth) acrylated epoxy compound include bisphenol type epoxy (meth) acrylate, cresol novolac type epoxy (meth) acrylate, carboxylic acid anhydride-modified epoxy (meth) acrylate, and phenol novolac type epoxy (meth) acrylate. Is mentioned.

  As the photocurable compound, a modified phenoxy resin obtained by converting a part of epoxy groups or a part of thiirane groups of a phenoxy resin having two or more epoxy groups or two or more thiirane groups into (meth) acryloyl groups is used. Also good. That is, a modified phenoxy resin having an epoxy group or thiirane group and a (meth) acryloyl group may be used.

  Further, the photocurable compound may be a crosslinkable compound or a non-crosslinkable compound.

  Specific examples of the crosslinkable compound include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, (poly ) Ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerol methacrylate acrylate, pentaerythritol tri (meth) acrylate, tri Examples include methylolpropane trimethacrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, polyester (meth) acrylate, and urethane (meth) acrylate.

  Specific examples of the non-crosslinkable compound include ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) ) Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (Meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, and the like.

  In 100% by weight of the photocurable conductive material, the content of the photocurable compound is preferably 60% by weight or more, more preferably 80% by weight or more, and preferably 90% by weight or less. When the content of the photocurable compound is not less than the above lower limit and not more than the above upper limit, the photocurable conductive material is appropriately photocured.

Photocationic polymerization initiator:
The above cationic photopolymerization initiator generates cations when irradiated with light. As the photocationic polymerization initiator, iodonium salts and sulfonium salts are preferably used. Commercially available products of the above cationic photopolymerization initiator include Sun-Aid SI-45L, Sun-Aid SI-60L, Sun-Aid SI-80L, Sun-Aid SI-100L, Sun-Aid SI-110L, and Sun-Aid SI-150L (manufactured by Sanshin Chemical Co., Ltd.) Adekaoptomer SP-150, Adekaoptomer SP-170, Adekaoptomer SP-171 (manufactured by ADEKA), UVE-1014 (manufactured by General Electronics), CD-1012 (manufactured by Sartomer), and the like. Can be mentioned.

Preferable examples of the anionic portion of the cationic photopolymerization initiator include PF ₆ , BF ₄ , and B (C ₆ F ₅ ) ₄ .

  Other specific examples of the cationic photopolymerization initiator include 2-butenyldimethylsulfonium tetrakis (pentafluorophenyl) borate, 2-butenyldimethylsulfonium tetrafluoroborate, 2-butenyldimethylsulfate. Phonium hexafluorophosphate, 2-butenyltetramethylenesulfonium tetrakis (pentafluorophenyl) borate, 2-butenyltetramethylenesulfonium tetrafluoroborate, 2-butenyltetramethylenesulfonium hexafluorophosphate, 3 -Methyl-2-butenyldimethylsulfonium tetrakis (pentafluorophenyl) borate, 3-methyl-2-butenyldimethylsulfonium tetrafluoroborate, 3-methyl-2-butenyldimethyls Phonium hexafluorophosphate, 3-methyl-2-butenyltetramethylenesulfonium tetrakis (pentafluorophenyl) borate, 3-methyl-2-butenyltetramethylenesulfonium tetrafluoroborate, 3-methyl-2- Butenyltetramethylenesulfonium hexafluorophosphate, 4-hydroxyphenylcinnamylmethylsulfonium tetrakis (pentafluorophenyl) borate, 4-hydroxyphenylcinnamylmethylsulfonium tetrafluoroborate, 4-hydroxyphenylcinnamylmethyl Sulfonium hexafluorophosphate, α-naphthylmethyltetramethylenesulfonium tetrakis (pentafluorophenyl) borate, α-naphthylmethyltetramethyl Sulfonium tetrafluoroborate, α-naphthylmethyltetramethylenesulfonium hexafluorophosphate, cinnamyldimethylsulfonium tetrakis (pentafluorophenyl) borate, cinnamyldimethylsulfonium tetrafluoroborate, cinnamyldimethylsulfonium Hexafluorophosphate, cinnamyltetramethylenesulfonium tetrakis (pentafluorophenyl) borate, cinnamyltetramethylenesulfonium tetrafluoroborate, cinnamyltetramethylenesulfonium hexafluorophosphate, biphenylmethyldimethylsulfonium tetrakis (penta Fluorophenyl) borate, biphenylmethyldimethylsulfonium tetrafluoroborate, Biphenylmethyldimethylsulfonium hexafluorophosphate, biphenylmethyltetramethylenesulfonium tetrakis (pentafluorophenyl) borate, biphenylmethyltetramethylenesulfonium tetrafluoroborate, biphenylmethyltetramethylenesulfonium hexafluorophosphate, phenylmethyldimethyl Sulfonium tetrakis (pentafluorophenyl) borate, phenylmethyldimethylsulfonium tetrafluoroborate, phenylmethyldimethylsulfonium hexafluorophosphate, phenylmethyltetramethylenesulfonium tetrakis (pentafluorophenyl) borate, phenylmethyltetramethylene Sulfonium tetrafluoroborate, phenyl Rutetramethylenesulfonium hexafluorophosphate, fluorenylmethyldimethylsulfonium tetrakis (pentafluorophenyl) borate, fluorenylmethyldimethylsulfonium tetrafluoroborate, fluorenylmethyldimethylsulfonium hexafluorophosphate, Examples include fluorenylmethyltetramethylenesulfonium tetrakis (pentafluorophenyl) borate, fluorenylmethyltetramethylenesulfonium tetrafluoroborate, and fluorenylmethyltetramethylenesulfonium hexafluorophosphate.

  The cationic photopolymerization initiator preferably releases inorganic acid ions upon irradiation with light, or releases organic acid ions containing boron atoms upon irradiation with light. The photocationic polymerization initiator is preferably a component that releases inorganic acid ions when irradiated with light, and is also preferably a component that releases organic acid ions containing boron atoms when irradiated with light.

The photocationic polymerization initiator that releases inorganic acid ions upon irradiation with light is preferably a compound having SbF ^6- or PF ^6- as an anion moiety. The photocationic polymerization initiator is preferably a compound having SbF ⁶⁻ as the anion moiety, and is preferably a compound having PF ⁶⁻ as the anion moiety.

Anionic portion of the cationic photopolymerization initiator is _{B (C 6 X 5) 4} - is preferably represented by. The photocationic polymerization initiator that releases an organic acid ion containing a boron atom is preferably a compound having an anion moiety represented by the following formula (1).

  In the above formula (1), X represents a halogen atom. X in the formula (1) is preferably a chlorine atom, a bromine atom or a fluorine atom, and more preferably a fluorine atom.

Anionic portion of the cationic photopolymerization initiator is _{B (C 6 F 5) 4} - is preferably represented by. As for the photocationic polymerization initiator which discharge | releases the said organic acid ion containing a boron atom, it is more preferable that it is a compound which has an anion part represented by following formula (1A).

  The type of the cationic photopolymerization initiator may be an ionic photoacid generating type or a nonionic photoacid generating type.

  The antimony complex is not particularly limited, but is preferably a sulfonium salt. Examples of the sulfonium salt that is the antimony complex include tetraphenyl (diphenyl sulfide-4,4′-diyl) bissulfonium di (antimony hexafluoride), tetra (4-methoxyphenyl) [diphenyl sulfide-4,4 ′. -Diyl] bissulfonium di (antimony hexafluoride), diphenyl (4-phenylthiophenyl) sulfonium hexamonium fluoride, and di (4-methoxyphenyl) [4-phenylthiophenyl] sulfonium hexamonium hexafluoride Etc.

  As a commercial item of the said antimony complex, Adeka optomer SP-170 (made by ADEKA) etc. are mentioned, for example.

  As a commercial item of the salt which has 6 hexafluoride phosphorus ion, WPI-113 (made by Wako Pure Chemical Industries), CPI-100P (made by San Apro), etc. are mentioned, for example.

  Content of the said photocationic polymerization initiator is not specifically limited. The content of the photocationic polymerization initiator is preferably 0.05 parts by weight or more, more preferably 0.15 parts by weight or more, preferably 2 parts by weight or less, based on 100 parts by weight of the photocurable compound. The amount is preferably 1 part by weight or less. When the content of the photocationic polymerization initiator is not less than the above lower limit and not more than the above upper limit, the photocurable conductive material is appropriately photocured.

Light curing retarder:
The photocuring retarder suppresses the progress of curing of the photocurable conductive material in a relatively short time after being irradiated with light. The photocuring retarder is a tertiary amine compound. The photocurable compound does not contain a photocuring retarder.

  Examples of the tertiary amine compound include triethylamine, trimethylamine, diisopropylethylamine, 1,3,5-triazine-2,4,6-trithiol, triglycidyl isocyanurate and 2,4,6-tri (glycidyloxy) -1, 3,5-triazine and the like can be mentioned.

  From the viewpoint of making voids less likely to be generated at the bonding interface and further improving the bonding reliability, the tertiary amine compound is preferably a compound having a triazine skeleton. The nitrogen atom in the triazine skeleton is preferably a tertiary amine nitrogen atom.

  From the viewpoint of making it more difficult to generate voids at the bonding interface and further improving the adhesion reliability, it is preferable that the tertiary amine compound has a cationic polymerizable group.

  Examples of the cationic polymerizable group include an epoxy group, a vinyl group, and an oxetane group.

  From the viewpoint of making it more difficult for voids to be generated at the bonding interface and further improving the adhesion reliability, the cationic polymerizable group is preferably an epoxy group.

  It is preferable that the said photocuring retarder adheres to the surface of electroconductive particle. In the photocurable conductive material, it is preferable that the photocurable conductive material contains the conductive particles and the photocurable retarder in a state where the photocurable retarder is attached to the surface of the conductive particles. The conductive particles and the photocuring retarder are preferably blended after the photocuring retarder is attached to the surface of the conductive particles. The conductive particles and the photocuring retarder are adhered to the surface of the conductive particles and then mixed with other components to obtain a photocurable conductive material. Is preferred. When the photo-setting retarder is attached to the surface of the conductive particles, the compounding components excluding the conductive particles between the electrodes and the conductive particles are effectively excluded during the conductive connection, The conduction reliability can be effectively increased.

  Content of the said photocuring retarder is not specifically limited. The content of the photocuring retarder is preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, preferably 10 parts by weight or less, more preferably 100 parts by weight of the photocurable compound. Is 5 parts by weight or less. When the content of the photocuring retarder is not less than the above lower limit and not more than the above upper limit, the photocurable conductive material is photocured with an appropriate delay.

  In a total of 100 wt% of the conductive particles and the photocuring retarder, the content of the photocuring retarder is preferably 0.01 wt% or more, more preferably 0.1 wt% or more, and still more preferably 1 % By weight or more, particularly preferably 3% by weight or more, most preferably 10% by weight or more, preferably 50% by weight or less, more preferably 30% by weight or less, still more preferably 20% by weight or less. When the content of the photocuring retarder is not less than the above lower limit and not more than the above upper limit, the photocurable conductive material is photocured with an appropriate delay. Further, the connection reliability is further increased.

Thermosetting compound:
The thermosetting compound has thermosetting properties. As for the said thermosetting compound, only 1 type may be used and 2 or more types may be used together.

  The said thermosetting compound may have thermosetting and photocurability, and does not need to have photocurability.

  Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenolic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds.

  From the viewpoint of easily controlling the curing of the photocurable conductive material or further enhancing the conduction reliability in the connection structure, the thermosetting compound is a thermosetting compound having an epoxy group or a thiirane group. It is preferable that a thermosetting compound having a thiirane group is included. The thermosetting compound having an epoxy group is an epoxy compound. The thermosetting compound having a thiirane group is an episulfide compound. From the viewpoint of enhancing the curability of the photocurable conductive material, the content of the compound having an epoxy group or thiirane group in the thermosetting compound is preferably 10% by weight or more, more preferably 20% by weight. % Or more and 100% by weight or less. The total amount of the thermosetting compound may be a compound having the epoxy group or thiirane group.

  Since the episulfide compound has a thiirane group instead of an epoxy group, it can be quickly cured at a low temperature. That is, the episulfide compound having a thiirane group can be cured at a lower temperature derived from the thiirane group as compared with the epoxy compound having an epoxy group.

  The thermosetting compound having an epoxy group or thiirane group preferably has an aromatic ring. The aromatic ring is preferably a benzene ring, a naphthalene ring or an anthracene ring, and more preferably a benzene ring or a naphthalene ring. Also, a naphthalene ring is preferred because it has a planar structure and can be cured more rapidly.

  The thermosetting compound may contain a phenoxy resin. In this case, you may use together a phenoxy resin and the thermosetting compound which has the said epoxy group or thiirane group. In this case, it is preferable that the thermosetting compound having the epoxy group or thiirane group is not a phenoxy resin.

  From the viewpoint of further enhancing the conduction reliability between the electrodes in the connection structure, the weight average molecular weight of the phenoxy resin is preferably 20000 or more, and preferably 70000 or less.

  The weight average molecular weight indicates a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

  When the phenoxy resin and the thermosetting compound having the epoxy group or thiirane group are used in combination, the photocurable conductive material includes the phenoxy resin and the thermosetting compound having the epoxy group or thiirane group. Is preferably included at a weight ratio of 1:99 to 99: 1, more preferably 10:90 to 90:10, still more preferably 20:80 to 80:20, and 30:70 to It is particularly preferred to include at 70:30.

  When using a thermosetting compound, the compounding ratio of a photocurable compound and a thermosetting compound is suitably adjusted according to the kind of a photocurable compound and a thermosetting compound. The compounding ratio of the photocurable compound and the thermosetting compound may be 1:99 to 99: 1, 10:90 to 90:10, or 20:80 to 80:20. It may be 30: 70-70: 30.

  In 100% by weight of the photocurable conductive material, the content of the thermosetting compound is preferably 0% by weight (not contained) or more, more preferably 0.3% by weight or more, and preferably 50% by weight or less. Preferably it is 30 weight% or less. When the thermosetting compound is contained and the content of the thermosetting compound is not less than the lower limit and not more than the upper limit, the photocurable conductive material is appropriately thermoset.

Thermosetting agent:
The said thermosetting agent is not specifically limited. A conventionally known thermosetting agent can be used as the thermosetting agent. Examples of the thermosetting agent include imidazole curing agents, amine curing agents, phenol curing agents, polythiol curing agents, and acid anhydrides. As for the said thermosetting agent, only 1 type may be used and 2 or more types may be used together.

  Since the photocurable conductive material can be cured more rapidly at a low temperature, the thermosetting agent is preferably an imidazole curing agent, a polythiol curing agent, or an amine curing agent. Moreover, since the storage stability of a photocurable conductive material can be improved, a latent curing agent is preferable. The latent curing agent is preferably a latent imidazole curing agent, a latent polythiol curing agent or a latent amine curing agent. The thermosetting agent may be coated with a polymer material such as polyurethane resin or polyester resin.

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

  The polythiol curing agent is not particularly limited, and examples thereof include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate. .

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

  The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, preferably 40 parts by weight or less, more preferably 30 parts by weight or less with respect to 100 parts by weight of the thermosetting compound. More preferably, it is 20 parts by weight or less. When the content of the thermosetting agent is not less than the above lower limit and not more than the above upper limit, the photocurable conductive material is sufficiently thermoset.

(Other details of connection structure)
Specific examples of the connection target member include electronic components such as semiconductor chips, capacitors, and diodes, and electronic components that are circuit boards such as printed boards, flexible printed boards, glass epoxy boards, and glass boards. The connection target member is preferably an electronic component.

  The connection structure manufacturing method according to the present invention and the connection structure according to the present invention include, for example, a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), a connection between a semiconductor chip and a flexible printed circuit board ( COF (Chip on Film)), connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)), or the like. Especially, the said photocurable conductive material is suitable for a FOG use or a COG use, and is more suitable for a COG use. The photocurable conductive material is preferably applied to the connection between the flexible printed circuit board and the glass substrate, or the connection between the semiconductor chip and the glass substrate, and more preferably applied to the connection between the semiconductor chip and the glass substrate.

  In the manufacturing method of the connection structure according to the present invention and the connection structure according to the present invention, a combination of the first connection target member and the second connection target member includes a glass substrate and a flexible printed circuit board or a semiconductor chip. It is preferable to be a combination of these, and it is more preferable to be a combination of a glass substrate and a semiconductor chip. Any of the first connection target member and the second connection target member may be a glass substrate, a flexible printed circuit board, or a semiconductor chip.

  Examples of the electrode provided on the connection target member include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a silver electrode, a molybdenum electrode, and a tungsten electrode. When the connection object member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. In addition, when the said electrode is an aluminum electrode, the electrode formed only with aluminum may be sufficient and the electrode by which the aluminum layer was laminated | stacked on the surface of the metal oxide layer may be sufficient. Examples of the material for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al, and Ga.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited only to the following examples.

(Example 1)
(1) Preparation of electroconductive particle composite The electroconductive particle by which the surface of the divinylbenzene resin particle (average particle diameter of 3 micrometers) was coat | covered with the nickel plating layer (thickness 0.1 micrometer) was prepared. Diglycidyl monoallyl isocyanurate diglycidyl monoallyl (“MA-DGIC” manufactured by Shikoku Kasei Kogyo Co., Ltd.) (compound having a triazine skeleton and an epoxy group) is attached to the surface of the conductive particles as a photo-setting retarder. A complex was obtained. The obtained conductive particle composite contains 99% by weight of conductive particles and 1% by weight of a photo-setting retarder.

(2) Production of anisotropic conductive film (photo-curable conductive material) 45 parts by weight of phenoxy resin ("PKHC" manufactured by Union Carbide) and 25 weights of bisphenol A type epoxy resin ("Epicoat 1009" manufactured by Mitsubishi Chemical Corporation) Parts, 10 parts by weight of a cationic photopolymerization initiator (“San-Aid SI-80” manufactured by Sanshin Chemical Industry Co., Ltd.), 2 parts by weight of a silane coupling agent (“SH6040” manufactured by Toray Dow Corning Silicone), and conductive particles 15 parts by weight of the composite (14.85 parts by weight of conductive particles and 0.15 part by weight of a photocuring retarder) and toluene were mixed to obtain a resin composition having a solid content of 50%. The obtained resin composition was applied onto polyethylene terephthalate that had been subjected to release treatment, and the solvent was dried to obtain an anisotropic conductive film having a thickness of 20 μm.

(3) Preparation of connection structure The transparent glass substrate (1st connection object member) which has the multilayer electrode pattern which is Ti / Al-Ti whose L / S is 15 micrometers / 15 micrometers on the upper surface was prepared. Further, a semiconductor chip (second connection target member) having a gold electrode pattern with L / S of 15 μm / 15 μm on the lower surface was prepared.

The obtained anisotropic conductive film was affixed on the chip mounting portion on the transparent glass substrate. Next, ultraviolet irradiation with a wavelength of 365 nm was applied from the upper side of the anisotropic conductive film so that the amount of light irradiation was 100 mJ / cm ² (first light irradiation step).

Sixty seconds after the first light irradiation, the semiconductor chip was stacked on the anisotropic conductive film so that the electrodes face each other. Thereafter, a pressure heating head was placed on the upper surface of the semiconductor chip while adjusting the temperature of the head. Regarding the connection conditions, heating and pressing at 110 ° C. and 50 MPa for 5 seconds (first heat application step) and ultraviolet irradiation from the transparent glass substrate side were performed simultaneously. Specifically, after only 2 seconds from the start of heating and pressing, ultraviolet irradiation with a wavelength of 365 nm was applied so that the amount of light irradiation was 600 mJ / cm ² (second light irradiation step). After 10 seconds from the start of heating and pressing, heating and pressing and ultraviolet irradiation were simultaneously terminated. Thereafter, the pressure was released. Then, it heated at 100 degreeC for 1 hour (2nd heat provision process), and obtained the connection structure.

(Example 2)
An anisotropic conductive film and a connection structure were obtained in the same manner as in Example 1 except that the cationic photopolymerization initiator was changed to “CPI-101A” manufactured by Sun Apro.

(Example 3)
An anisotropic conductive film and a connection structure were obtained in the same manner as in Example 1 except that the photocuring retarder was changed to 1,3,5-triazine-2,4,6-trithiol.

Example 4
The manufacturing method of the connection structure was changed as follows.

  The anisotropic conductive film obtained in Example 1 was prepared.

  A transparent glass substrate (first connection target member) having a multilayer electrode pattern of L / S of Ti—Al—Ti with 10 μm / 10 μm on the upper surface was prepared. Further, a semiconductor chip (second connection target member) having a gold electrode pattern having a L / S of 10 μm / 10 μm on the lower surface was prepared.

The obtained anisotropic conductive film was affixed on the chip mounting portion on the transparent glass substrate. Next, ultraviolet irradiation with a wavelength of 365 nm was applied from the upper side of the anisotropic conductive film so that the amount of light irradiation was 200 mJ / cm ² (first light irradiation step).

  Sixty seconds after the first light irradiation, the semiconductor chip was stacked on the anisotropic conductive film so that the electrodes face each other. Thereafter, a pressure heating head was placed on the upper surface of the semiconductor chip while adjusting the temperature of the head. Regarding connection conditions, heating and pressing (first heat application step) at 110 ° C. and 50 MPa for 30 seconds were performed to obtain a connection structure.

(Example 5)
An anisotropic conductive film and a connection structure were obtained in the same manner as in Example 1 except that the photocuring retarder was changed to triethylamine.

(Example 6)
In Example 6, the conductive particles and the photocuring retarder were used separately without being combined.

  45 parts by weight of phenoxy resin (“PKHC” manufactured by Union Carbide), 25 parts by weight of bisphenol A type epoxy resin (“Epicoat 1009” manufactured by Mitsubishi Chemical Corporation), and photocationic polymerization initiator (“Sun Aid” manufactured by Sanshin Chemical Industry Co., Ltd.) SI-80 ") 10 parts by weight, 2 parts by weight of a silane coupling agent (" SH6040 "manufactured by Toray Dow Corning Silicone) and a photo-setting retarder (diglycidyl monoallyl isocyanurate (" Shikoku Kasei Kogyo "MA- DGIC ") (a compound having a triazine skeleton and an epoxy group)) 1 part by weight and 20 parts by weight of conductive particles were mixed with toluene to obtain a resin composition having a solid content of 50%. The obtained resin composition was applied onto polyethylene terephthalate that had been subjected to release treatment, and the solvent was dried to obtain an anisotropic conductive film having a thickness of 20 μm. In addition, the used electroconductive particle is an electroconductive particle with which the surface of the divinylbenzene resin particle (average particle diameter of 3 micrometers) was coat | covered with the nickel plating layer (thickness 0.1 micrometer).

(Example 7)
An anisotropic conductive film and a connection structure were obtained in the same manner as in Example 6 except that the photocuring retarder was changed to 1,3,5-triazine-2,4,6-trithiol.

(Example 8)
An anisotropic conductive film and a connection structure were obtained in the same manner as in Example 6 except that the photocuring retarder was changed to triethylamine.

Example 9
After depositing nickel particles (100 nm) as a core substance on the surface of divinylbenzene resin particles (average particle diameter 3 μm), conductive particles with protrusions coated with a nickel plating layer (thickness 0.1 μm) were prepared. An anisotropic conductive film and a connection structure were obtained in the same manner as in Example 1 except that the conductive particles were changed to the conductive particles with protrusions.

(Example 10)
After depositing nickel particles (average particle diameter of 100 nm) as a core substance on the surface of divinylbenzene resin particles (average particle diameter of 3 μm), conductive particles with protrusions coated with a nickel plating layer (thickness of 0.1 μm) are used. Obtained. The surface of the conductive particles is further uniformly coated with organic insulating particles (insulating particles having an average particle size of 200 nm made of a polymer of MMA (methyl methacrylate)), and the insulating particles are coated and conductive particles with protrusions. Got. In the obtained insulating particle covering and conductive particles with protrusions, the insulating particles covered about 60% of the surface area of the conductive particles. An anisotropic conductive film and a connection structure were obtained in the same manner as in Example 1 except that the conductive particles were changed to the insulating particle coating and the conductive particles with protrusions.

(Example 11)
The electroconductive particle by which the surface of the divinylbenzene resin particle (average particle diameter 2.5 micrometers) was coat | covered with the nickel plating layer (thickness 0.1 micrometer) was prepared. An anisotropic conductive film and a connection structure were obtained in the same manner as in Example 1 except that the conductive particles were changed to the conductive particles with protrusions.

(Comparative Example 1)
An anisotropic conductive film was obtained in the same manner as in Example 1 except that the photocuring retarder was not used. A connection structure was obtained in the same manner as in Example 1 except that the first light irradiation step was not performed.

(Comparative Example 2)
An anisotropic conductive film and a connection structure were obtained in the same manner as in Example 1 except that the photocationic polymerization initiator was changed to a photoradical generator (“IRGACURE 819” manufactured by Ciba Japan).

(Comparative Example 3)
An anisotropic conductive film and a connection structure were obtained in the same manner as in Example 1 except that the photocuring retarder was changed to polyglycerol polyglycidyl ether (“Deconal EX-421” manufactured by Nagase Chemtech).

(Comparative Example 4)
An anisotropic conductive film and a connection structure were obtained in the same manner as in Example 1 except that the photocuring retarder was changed to “18-crown-6-ether” manufactured by Wako Pure Chemical Industries.

(Evaluation)
(1) Viscosity Viscosity η1 of the photocurable conductive material before the first light irradiation, UV irradiation with a wavelength of 365 nm, and a light irradiation amount of 150 mJ / cm ² (light irradiation intensity at the time of manufacturing the connection structure) The viscosity η2 of the photocurable conductive material 60 seconds after the irradiation was measured. For the measurement of viscosity, “AR-2000ex” manufactured by TA Instruments was used. The viscosity was determined according to the following criteria.

[Criteria for viscosity]
A: η2 / η1 is 1.3 or less B: η2 / η1 exceeds 1.3 and 1.5 or less C: η2 / η1 exceeds 1.5

(2) Presence / absence of voids A cross section of the obtained connection structure was observed, and it was observed with an optical microscope whether or not voids were generated in the connection portion where the photocurable conductive material was cured. The presence or absence of voids was determined according to the following criteria. If there are no voids, the connection reliability increases, and the fewer the voids, the higher the connection reliability.

[Criteria for the presence or absence of voids]
○: No void △: There is a slight void, but there is no void larger than the electrode L / S, pitch ×: There is a void larger than the size between adjacent electrodes

(3) Connection state between electrode and conductive particle The cross section of the obtained connection structure is observed, and the connection part where the photocurable conductive material is cured is sandwiched between the electrode and the conductive particle. It was evaluated whether there was a place.

[Connection between electrode and conductive particles]
○○: The connection part where the photocurable conductive material is cured is not sandwiched between the electrode and the conductive particle. ○: Photocuring is performed so that no poor connection occurs between the electrode and the conductive particle. The connection part in which the conductive conductive material is cured is slightly sandwiched. Δ: The connection part in which the photocurable conductive material is cured is slightly sandwiched between the electrode and the conductive particles to such an extent that a connection failure does not occur. X: The connection part where the photocurable conductive material is cured is sandwiched between the electrode and the conductive particles to the extent that a connection failure may occur.

(4) Warpage of second connection target member In the obtained connection structure, the amount of warpage of the semiconductor chip as the second connection target member was measured. The connection structure was arranged on a horizontal surface, and the difference between the maximum height position and the minimum height position in the measurement at the long side 25 mm of the semiconductor chip as the second connection target member was taken as the amount of warpage. The warpage of the second connection target member was determined according to the following criteria. In addition, when the curvature amount of the 2nd connection object member was large, it confirmed that the 2nd connection object member tends to peel from a connection part easily.

[Criteria for determining warpage of second connection target member]
○: The warpage amount of the second connection target member is less than 10 μm. ○: The warpage amount of the second connection target member is 10 μm or more and less than 15 μm. Δ: The warpage amount of the second connection target member is 15 μm or more and less than 20 μm. : The warpage amount of the second connection target member is 20 μm or more.

(5) Connection reliability between electrodes The resistance value between the electrodes in the obtained connection structure was measured by a four-terminal method. Then, the resistance value between the electrodes in the connection structure treated for 500 hours in an environment of 85 ° C. and humidity of 85% was measured again. The connection reliability between the electrodes was evaluated according to the following evaluation criteria according to the increasing ratio of the resistance value after being left in a high temperature and high humidity environment.

[Judgment criteria for connection reliability between electrodes]
○○: Resistance value increase rate is less than 2 times ○: Resistance value increase rate is 2 times or more and less than 4 times △: Resistance value increase rate is 4 times or more and less than 8 times ×: Resistance value increase rate is 8 times or more

(6) Conduction reliability between electrodes The resistance value between the electrodes in the obtained connection structure was measured by a four-terminal method. The conduction reliability between the electrodes was determined according to the following criteria.

[Judgment criteria for conduction reliability between electrodes]
○○: Resistance value is less than 1.5Ω ○: Resistance value is 1.5Ω or more and less than 2.0Ω Δ: Resistance value is 2.0Ω or more and less than 2.5Ω ×: Resistance value is 2.5Ω or more

  The results are shown in Table 1 below.

  In Example 1 and Examples 9 and 10, the evaluation result of connection reliability and conduction reliability is “◯◯”, but the rate of increase in resistance value of connection reliability is that of Examples 9 and 10. However, the resistance value of conduction reliability was smaller in Examples 9 and 10 than in Example 1. Moreover, in Example 10, the insulation reliability between the electrodes adjacent in the lateral direction was superior to those in Examples 1 and 9.

DESCRIPTION OF SYMBOLS 1 ... Connection structure 2 ... 1st connection object member 2a ... 1st electrode 3 ... 2nd connection object member 3a ... 2nd electrode 4 ... Connection part 4A ... Photocurable conductive material layer 4B ... 1st Photo-curing conductive material layer 4C subjected to light irradiation ... Photo-curing conductive material layer subjected to second light irradiation and first heat application 11 ... Cured product of photo-curing component 21 ... Conductive particles DESCRIPTION OF SYMBOLS 22 ... Conductive particle composite 31 ... Base material particle 32 ... Conductive part 33 ... Photocuring retarder 51 ... Thermocompression bonding head

Claims (15)

It is used for connection of connection target members having electrodes on the surface, and is a conductive material having photocurability,
Conductive particles;
A photocurable compound;
A photocationic polymerization initiator;
A light curing retarder,
A photocurable conductive material, wherein the photocurable retarder is a tertiary amine compound.   The photocurable conductive material according to claim 1, wherein the tertiary amine compound is a compound having a triazine skeleton.   The photocurable conductive material according to claim 1 or 2, wherein the tertiary amine compound has a cationic polymerizable group.   The photocurable conductive material according to claim 3, wherein the cationically polymerizable group is an epoxy group. The cationic photopolymerization initiator is a cationic photopolymerization initiator that generates an acid by irradiation with light,
The photocurable conductive material according to any one of claims 1 to 4, wherein the photocuring retarder is capable of capturing an acid generated from a photocationic polymerization initiator. The first connection target member having the first electrode on the surface is connected to the second connection target member having the second electrode on the surface, and the first electrode and the second electrode are electrically connected. Used to connect and obtain a connection structure,
After the photocurable conductive material is disposed on the surface of the first connection target member, the first light irradiation is performed on the photocurable conductive material from the side opposite to the first connection target member side. Next, the first connection target member of the photocurable conductive material that has been irradiated with the first light so that the conductive particles are positioned between the first electrode and the second electrode. The second connection object member is disposed on the surface opposite to the side, and the second light irradiation and heat are applied to the photocurable conductive material when or after the second connection object member is disposed. 6. The method according to claim 1, wherein the connection structure is obtained through a step of forming a cured product obtained by curing at least one of the application of the photocurable conductive material. The photocurable conductive material described in 1.   When the second connection target member is disposed or after the second connection target member is disposed, a second light irradiation is performed on the photocurable conductive material, and a cured product obtained by curing the photocurable conductive material is formed. The photocurable conductive material according to claim 6, which is used for obtaining the connection structure.   When the second connection target member is arranged or after being arranged, heat is applied to the photocurable conductive material, and the photocurable conductive material is cured to form a cured product, The photocurable conductive material according to claim 6, which is used for obtaining a connection structure.   When or after the second connection target member is arranged, the photocurable conductive material is irradiated with the second light and heat is applied to the photocurable conductive material, and photocuring is performed. The photocurable conductive material according to claim 6, which is used for obtaining the connection structure through a step of forming a cured product obtained by curing the conductive conductive material. It is a conductive material having photocurability and thermosetting property,
The photocurable conductive material according to any one of claims 1 to 6, 8, and 9, comprising a thermosetting compound and a thermosetting agent. A first connection object member having a first electrode on its surface;
A second connection target member having a second electrode on its surface;
A connection portion connecting the first connection target member and the second connection target member;
The connection portion is formed by curing the photocurable conductive material according to any one of claims 1 to 10,
A connection structure in which the first electrode and the second electrode are electrically connected by the conductive particles. Using the photocurable conductive material according to any one of claims 1 to 10, and
Using the first connection target member having the first electrode on the surface and the second connection target member having the second electrode on the surface,
Disposing the photocurable conductive material on the surface of the first connection target member;
Performing a first light irradiation on the photo-curable conductive material disposed on the surface of the first connection target member from the side opposite to the first connection target member side;
The first connection target member side of the photocurable conductive material subjected to the first light irradiation so that the conductive particles are positioned between the first electrode and the second electrode; Arranging the second connection object member on the opposite surface;
A step of performing at least one of second light irradiation and heat application to the photocurable conductive material at or after the second connection target member is arranged,
A connection portion connecting the first connection target member and the second connection target member is formed of a cured product of the photocurable conductive material, and the first electrode and the second electrode Is electrically connected by the conductive particles.   The said 2nd light irradiation process is a 2nd light irradiation process which performs a 2nd light irradiation to the said photocurable conductive material at the time of arrangement | positioning or after arrangement | positioning of the said 2nd connection object member. The manufacturing method of the connection structure of description.   The connection structure according to claim 12, wherein the second light irradiation step is a heat application step of applying heat to the photocurable conductive material at or after the second connection target member is arranged. Body manufacturing method.   In the second light irradiation step, the second light irradiation is performed on the photocurable conductive material during or after the second connection target member is disposed, and heat is applied to the photocurable conductive material. The manufacturing method of the connection structure of Claim 12 which is a 2nd light irradiation and heat | fever provision process to perform.

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