Resin composition and method for producing connected structure

Abstract

Provided is a resin composition (11) capable of improving the trapping properties of a semiconductor chip (3) that flies at a high speed. This resin composition (11) contains a thermosetting component (11B), a flux (11C), a thixotropic agent that is liquid at 25 DEG C, and solder particles (11A).

Description

Technical Field

[0001] The present invention relates to a resin composition containing solder particles and a method for producing a connection structure using the resin composition. Background Art

[0002] Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In these anisotropic conductive materials, conductive particles are dispersed in a binder. Solder particles are widely used as the conductive particles.

[0003] These anisotropic conductive materials are used to form various connection structures. Examples of connection methods using these anisotropic conductive materials include connecting a flexible printed circuit board to a glass substrate (FOG (Film on Glass)), connecting a semiconductor chip to a flexible printed circuit board (COF (Chip on Film)), connecting a semiconductor chip to a glass substrate (COG (Chip on Glass)), and connecting a flexible printed circuit board to a glass epoxy substrate (FOB (Film on Board)).

[0004] In recent years, devices using connection structures have been increasingly miniaturized and lightweight. This has led to a demand for connection structures that utilize micro-LED (micro-light emitting diode) chips, among other micro-semiconductor chips. Laser transfer has attracted attention as a method for placing micro-LED chips and other micro-semiconductor chips on circuit boards.

[0005] Patent Document 1 below discloses a laser transfer device. In this laser transfer device, a transfer source substrate, on which multiple elements are formed, is positioned above a transfer destination substrate. Laser light is irradiated from above the transfer source substrate, causing multiple transfer target elements, among the multiple elements, to move downward, thereby transferring the target elements to the transfer destination substrate.

[0006] Patent Document 2 below discloses a transfer method for transferring a chip component held on a transfer substrate via a photocurable adhesive layer to a target substrate. The transfer method comprises an exposure step of pattern-exposing the adhesive layer with light of a wavelength that cures the adhesive layer, thereby locally reducing the adhesive strength of the adhesive layer; and a laser lift-off step of transferring the chip component to the target substrate using a laser lift-off method after the exposure step.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: WO2020 / 188780A1

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2020-53558 Summary of the Invention

[0011] Technical problem to be solved by the invention

[0012] In the method of arranging semiconductor chips using laser transfer, a plurality of semiconductor chips can be collectively moved from a wafer substrate (transfer source substrate) and mounted on a circuit substrate (transfer destination substrate), thereby improving the productivity of the connection structure.

[0013] However, when placing semiconductor chips using laser transfer, the impact of the high-speed flying semiconductor chip landing on the circuit board (the component to be connected) sometimes prevents the semiconductor chip from being accurately placed at the desired location on the circuit board (the component to be connected). If the semiconductor chip is misaligned during placement, it may be impossible to establish a conductive connection between the upper and lower electrodes.

[0014] An object of the present invention is to provide a resin composition capable of improving the ability to capture semiconductor chips flying at high speeds. Another object of the present invention is to provide a method for producing a connection structure using the resin composition.

[0015] Technical means to solve technical problems

[0016] The present inventors have conducted intensive studies and have found that semiconductor chips flying at high speed by laser transfer or the like can be well captured by disposing a specific resin composition on the surface of a circuit board (connection target member).

[0017] This specification discloses the following resin composition and a method for producing a connection structure using the resin composition.

[0018] Item 1. A resin composition comprising: a thermosetting component, a flux, a thixotropic agent that is liquid at 25° C., and solder particles.

[0019] Item 2. The resin composition according to Item 1, wherein the soldering flux comprises a first soldering flux having an even number of carbon atoms in its main chain and a second soldering flux having an odd number of carbon atoms in its main chain.

[0020] Item 3. The resin composition according to Item 2, wherein the hydrogen bonding term δH in the Hansen solubility parameter of the thixotropic agent is 10 MPa 1 / 2 In the above, the number of carbon atoms in the main chain of the first flux is an even number of 4 to 14, and the number of carbon atoms in the main chain of the second flux is an odd number of 3 to 11.

[0021] Item 4. The resin composition according to Item 2 or 3, wherein the first flux has an average particle size of 10 μm or less.

[0022] Item 5. The resin composition according to any one of Items 2 to 4, wherein the second flux is soluble in the thixotropic agent at 25°C.

[0023] Item 6. The resin composition according to any one of Items 2 to 5, wherein the content of the second flux is 1% by weight or more and 20% by weight or less in 100% by weight of the resin composition.

[0024] Item 7. The resin composition according to any one of Items 1 to 6, wherein the thixotropic agent contains glycerin.

[0025] Item 8. The resin composition according to any one of Items 1 to 7, wherein a content of the flux in 100 wt % of the resin composition is 5 wt % or more and 25 wt % or less.

[0026] Item 9. The resin composition according to any one of Items 1 to 8, wherein the average particle size of the solder particles is 10 μm or less.

[0027] Item 10. A method for manufacturing a connection structure, comprising: a first configuration step, which uses the resin composition described in any one of items 1 to 9 to configure the resin composition on the surface of a first connection object member having at least one first electrode on its surface; a second configuration step, which uses a laser transfer method to move a second connection object member having at least one second electrode on its surface to the surface of the resin composition opposite to the first connection object member, and configure the second connection object member in a manner such that the first electrode and the second electrode are opposite to each other; and a connection step, which forms a connection portion for connecting the first connection object member and the second connection object member with the resin composition by heating the resin composition to a temperature above the melting point of the solder particles, and electrically connects the first electrode and the second electrode through the solder portion in the connection portion.

[0028] Item 11. A method for manufacturing a connection structure according to Item 10, wherein, in the second configuration step, the second connection object member is moved to the surface of the resin composition opposite to the first connection object member at a speed of 1 cm / s or more by a laser transfer method, and the second connection object member is configured in a manner such that the first electrode and the second electrode are opposite to each other.

[0029] Effects of the Invention

[0030] The resin composition of the present invention comprises a thermosetting component, a flux, a thixotropic agent that is liquid at 25° C., and solder particles. The resin composition of the present invention, having the above-described structure, can improve the ability to capture semiconductor chips flying at high speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a cross-sectional view schematically showing a connection structure obtained using the resin composition according to one embodiment of the present invention.

[0032] Figure 2 This is a cross-sectional view for explaining the steps of an example of a method for producing a connection structure using the resin composition according to one embodiment of the present invention.

[0033] Figure 3 This is a cross-sectional view for explaining the steps of an example of a method for producing a connection structure using the resin composition according to one embodiment of the present invention.

[0034] Figure 4 This is a cross-sectional view for explaining the steps of an example of a method for producing a connection structure using the resin composition according to one embodiment of the present invention.

[0035] Figure 5 It is a cross-sectional view showing a modified example of the connection structure. DETAILED DESCRIPTION

[0036] Hereinafter, the present invention will be described in detail.

[0037] (Resin composition)

[0038] The resin composition of the present invention comprises a thermosetting component, a flux, a thixotropic agent that is liquid at 25° C., and solder particles.

[0039] Conventional methods for placing semiconductor chips using laser transfer have sometimes failed to accurately position the semiconductor chip in the desired location on the circuit board (the component to be connected) due to the impact of the high-speed flying semiconductor chip landing on the circuit board (the component to be connected). If the semiconductor chip is misaligned during placement, it may be impossible to establish a conductive connection between the upper and lower electrodes.

[0040] The resin composition of the present invention, due to its aforementioned structure, can improve the ability to capture semiconductor chips flying at high speeds. In particular, it can improve the ability to capture semiconductor chips flying at high speeds using the laser transfer method. As a result, the flying semiconductor chips can be accurately positioned at a predetermined location on the circuit board (connection target component) (effectively suppressing positional deviation during placement of the semiconductor chips).

[0041] In the present invention, use of a specific resin composition greatly contributes to obtaining the above-mentioned effects.

[0042] In the manufacturing method of the connection structure, the resin composition is configured on the surface of the connection object member (circuit board, transfer target substrate) and used. In the manufacturing method of the connection structure, the resin composition is preferably used to well capture semiconductor chips flying at high speed by a laser transfer method. The resin composition is preferably a resin composition for capturing semiconductor chips using a laser transfer method.

[0043] In particular, the resin composition of the present invention is suitable for use in connecting semiconductor chips using a laser transfer method (use of a resin composition for connecting semiconductor chips using a laser transfer method). More specifically, the resin composition of the present invention is more suitable for use in connecting a semiconductor chip to a substrate using a laser transfer method (use of a resin composition for connecting a semiconductor chip to a substrate using a laser transfer method).

[0044] The contact angle of the resin composition with respect to water at 25°C is preferably 65° or less, more preferably 60° or less, further preferably 55° or less, and particularly preferably 45° or less. If the contact angle of the resin composition with respect to water at 25°C is below the upper limit, the capture property of the semiconductor chip flying at high speed by the laser transfer method can be further improved. Specifically, the electrodes of the semiconductor chip usually contain gold, copper or their alloys, so the surface of the electrode of the semiconductor chip is mostly hydrophilic. When the contact angle of the resin composition of the present invention with respect to water at 25°C is below the upper limit, the surface of the resin composition is hydrophilic, so the affinity with the surface of the electrode of the semiconductor chip is high, and when it is arranged on the surface of the connection object member (circuit substrate), the capture property of the semiconductor chip flying at high speed by the laser transfer method can be further improved. The lower limit of the contact angle of the resin composition with respect to water at 25°C is not particularly limited. The contact angle of the resin composition with respect to water at 25°C can be 0° or more, can exceed 0°, can be 1° or more, and can be 5° or more. The range of the contact angle can be set by appropriately selecting the lower limit value and the upper limit value.

[0045] The contact angle of the resin composition with respect to water at 25°C can be measured, for example, by the following method. 1 ml of water is dropped onto the surface of the resin composition, and the contact angle of the resin composition with respect to water is measured using a contact angle measuring apparatus. Examples of the contact angle measuring apparatus include the "DMo-601" manufactured by KYOWA Corporation. The contact angle of the resin composition with respect to water at 25°C is measured 10 seconds after the water is placed on the surface of the resin composition.

[0046] The contact angle of the resin composition with respect to water at 25°C can be adjusted by the following methods, among others: Combining multiple backbones of a thermosetting component such as an epoxy resin; Selecting the backbone of a thermosetting component such as an epoxy resin; Selecting the side chains of a thermosetting component such as an epoxy resin; Dispersing an additive that is liquid at 25°C in the resin composition.

[0047] The resin composition is preferably in a liquid state at 25°C. A paste is included in a liquid state. The resin composition is preferably in a paste state at 25°C. The resin composition contains solder particles and is therefore a conductive material. The resin composition is preferably a conductive paste. The resin composition is preferably a conductive paste at 25°C. In these cases, the resin composition can be applied more thinly and well to the surface of the connection object member, the ability to capture semiconductor chips flying at high speed by laser transfer can be more effectively improved, and the cohesion of the solder during conductive connection can be more effectively improved.

[0048] The viscosity (η25) of the resin composition at 25°C is preferably 30 Pa·s or more, more preferably 50 Pa·s or more, preferably 250 Pa·s or less, and more preferably 200 Pa·s or less. If the viscosity (η25) is above the lower limit, the capture of semiconductor chips flying at high speed by the laser transfer method can be more effectively improved. If the viscosity (η25) is below the upper limit, the resin composition can be well applied thinly to the surface of the connection object component, which can effectively improve the cohesion of the solder during conductive connection. The viscosity (η25) can be appropriately adjusted according to the type and amount of the blended components.

[0049] The viscosity (η25) can be measured under the conditions of 25° C. and 5 rpm using, for example, an E-type viscometer (“TVE-22L” manufactured by Toki Sangyo Co., Ltd.).

[0050] The viscosity (ηmp) of the resin composition at the melting point of the solder particles is preferably 0.1Pa·s or more, more preferably 1Pa·s or more, preferably 10Pa·s or less, and more preferably 5Pa·s or less. The viscosity (ηmp) can be appropriately adjusted according to the type and amount of the ingredients. If the viscosity (ηmp) is above the lower limit and below the upper limit, the cohesion of the solder during conductive connection can be more effectively improved, the gap at the connecting portion can be more effectively suppressed, and the overflow of the resin composition outside the connecting portion can be more effectively suppressed. If the viscosity (ηmp) is above the lower limit and below the upper limit, the insulation reliability between the electrodes can be more effectively improved, and the conduction reliability between the electrodes can be more effectively improved.

[0051] The viscosity (ηmp) can be measured, for example, using a viscoelasticity measuring instrument ("HAAKE" manufactured by SCIENTIFIC) under the following conditions: a stress control of 1 Pa, a frequency of 1 Hz, a heating rate of 20°C / min, and a measurement temperature range of 25°C to 200°C. However, if the melting point of the solder particles exceeds 200°C, the upper temperature limit is set to the melting point of the solder particles. In this measurement, the viscosity (ηmp) is calculated by reading the viscosity at the melting point of the solder particles.

[0052] The resin composition can be used as a conductive paste, a conductive film, or the like. The conductive paste is preferably an anisotropic conductive paste, and the conductive film is preferably an anisotropic conductive film. To more effectively suppress positional shifting during the configuration of connected components and more effectively improve solder cohesion during conductive connection, the resin composition is preferably in a paste form, preferably a conductive paste. The resin composition is suitable for electrical connection of electrodes. The resin composition is preferably a circuit connection material.

[0053] The following describes the components contained in the resin composition. In this specification, the term "(meth)acrylate" refers to both acrylate and methacrylate. The term "(meth)acrylic" refers to both acrylic and methacrylic. The term "(meth)acryloyl" refers to both acryloyl and methacryloyl.

[0054] (Thermosetting component)

[0055] The resin composition of the present invention contains a thermosetting component. The thermosetting component preferably contains a thermosetting compound. The resin composition may contain a thermosetting agent as a thermosetting component, or may not contain a thermosetting agent as a thermosetting component. In the resin composition of the present invention, due to the above-mentioned structure, even when the resin composition does not contain a thermosetting agent, the capture of semiconductor chips flying at high speed by the laser transfer method can be improved. From the viewpoint of more effectively improving the cohesion of the solder during conductive connection, the resin composition preferably does not contain a thermosetting agent. In order to make the resin composition cure more effectively, the resin composition may contain a curing accelerator as a thermosetting component.

[0056] (Thermosetting component: thermosetting compound)

[0057] The resin composition of the present invention preferably contains a thermosetting compound. The thermosetting compound is a compound that can be cured by heating. The thermosetting compound is not particularly limited. Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenolic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, polysiloxane compounds, and polyimide compounds. From the perspective of improving the curability and viscosity of the resin composition and further improving the conduction reliability, the thermosetting compound is preferably an epoxy compound or an episulfide compound, and more preferably an epoxy compound. The resin composition preferably contains an epoxy compound or an episulfide compound, and more preferably contains an epoxy compound. The thermosetting compound may be used alone or in combination of two or more.

[0058] The epoxy compound is a compound having at least one epoxy group. Examples of the epoxy compound include bisphenol A epoxy compounds, bisphenol F epoxy compounds, bisphenol S epoxy compounds, phenol novolac epoxy compounds, biphenyl epoxy compounds, biphenyl novolac epoxy compounds, biphenol epoxy compounds, naphthalene epoxy compounds, fluorene epoxy compounds, phenol aralkyl epoxy compounds, naphthol aralkyl epoxy compounds, dicyclopentadiene epoxy compounds, anthracene epoxy compounds, epoxy compounds having an adamantane skeleton, epoxy compounds having a tricyclodecane skeleton, naphthylene ether epoxy compounds, and epoxy compounds having a triazine core in the skeleton. The epoxy compounds may be used alone or in combination of two or more.

[0059] The epoxy compound is liquid or solid at room temperature (25°C). If the epoxy compound is solid at room temperature, the melting temperature of the epoxy compound is preferably below the melting point of the solder particles. The use of this preferred epoxy compound provides high viscosity during the bonding phase of the components to be connected, which can suppress positional shifting between the component to be connected (circuit board) and the semiconductor chip when subjected to acceleration due to impacts such as transportation. Furthermore, the heat generated during curing significantly reduces the viscosity of the resin composition, enabling efficient aggregation of the solder during conductive connection.

[0060] From the viewpoint of more effectively improving insulation reliability and more effectively improving conduction reliability, the thermosetting component preferably includes an epoxy compound, and the thermosetting compound preferably includes an epoxy compound.

[0061] From the viewpoint of more efficiently arranging the solder on the electrode, the thermosetting compound preferably includes a thermosetting compound having a polyether skeleton.

[0062] Examples of the thermosetting compound having a polyether skeleton include compounds having glycidyl ether groups at both ends of an alkyl chain having 3 to 12 carbon atoms, and polyether epoxy compounds having a polyether skeleton having 2 to 4 carbon atoms and a structural unit composed of 2 to 10 consecutively bonded polyether skeletons.

[0063] From the viewpoint of more effectively improving the heat resistance of the cured product, the thermosetting compound preferably includes a thermosetting compound having an isocyanuric acid skeleton.

[0064] Examples of the thermosetting compound having an isocyanuric acid skeleton include triisocyanurate-type epoxy compounds, and examples include the TEPIC series (TEPIC-G, TEPIC-S, TEPIC-SS, TEPIC-HP, TEPIC-L, TEPIC-PAS, TEPIC-VL, and TEPIC-UC) manufactured by Nissan Chemical Industries, Ltd.

[0065] From the perspectives of more efficiently placing solder on the electrodes, more effectively improving the electrical conductivity reliability between the upper and lower electrodes to be connected, and more effectively suppressing discoloration of the thermosetting compound, the thermosetting compound preferably has high heat resistance, and more preferably includes a novolac-type epoxy compound. Novolac-type epoxy compounds have relatively high heat resistance.

[0066] In the resin composition 100% by weight, the content of the thermosetting compound is preferably 5% by weight or more, more preferably 8% by weight or more, further preferably 10% by weight or more, preferably 99% by weight or less, more preferably 90% by weight or less, further preferably 80% by weight or less, and particularly preferably 70% by weight or less. When the content of the thermosetting compound is above the lower limit and below the upper limit, it is possible to more effectively improve the capture of semiconductor chips flying at high speed by a laser transfer method, it is possible to more efficiently configure solder on the electrode, it is possible to more effectively improve the insulation reliability between electrodes, it is possible to more effectively improve the conduction reliability between electrodes. From the viewpoint of more effectively improving the impact resistance of the connection structure obtained, it is preferred that the content of the thermosetting compound is many.

[0067] In the resin combination 100% by weight, the content of the epoxy compound is preferably more than 5% by weight, more preferably more than 8% by weight, further preferably more than 10% by weight, preferably less than 99% by weight, more preferably less than 90% by weight, further preferably less than 80% by weight, particularly preferably less than 70% by weight. When the content of the epoxy compound is more than the lower limit and less than the upper limit, it is possible to more effectively improve the capture of the semiconductor chip flying at high speed by the laser transfer method, it is possible to more efficiently configure solder on the electrode, it is possible to more effectively improve the insulation reliability between electrodes, it is possible to more effectively improve the conduction reliability between electrodes. From the viewpoint of further improving the impact resistance of the connection structure obtained, it is preferred that the content of the epoxy compound is many.

[0068] In the resin combination 100 wt %, the content of the novolac type epoxy compound is preferably more than 1 wt %, more preferably more than 3 wt %, more preferably more than 5 wt %, preferably less than 99 wt %, more preferably less than 90 wt %, more preferably less than 80 wt %, particularly preferably less than 70 wt %. If the content of the novolac type epoxy compound is more than the lower limit and below the upper limit, the capture of the semiconductor chip flying at high speed by the laser transfer method can be more effectively improved, solder can be more efficiently configured on the electrode, the insulation reliability between the electrodes can be more effectively improved, and the conduction reliability between the electrodes can be more effectively improved. From the viewpoint of further improving the impact resistance of the connection structure obtained, the content of the preferably novolac type epoxy compound is many.

[0069] (Flux)

[0070] The resin composition contains a soldering flux. By using the soldering flux, the cohesion of the solder during the conductive connection can be more effectively improved.

[0071] Examples of the soldering flux include zinc chloride, mixtures of zinc chloride and inorganic halides, mixtures of zinc chloride and inorganic acids, molten salts, phosphoric acid, phosphoric acid derivatives, organic acids, organic acid amine salts, organic halides, hydrazine, amine compounds other than organic acid amine salts, and rosin. The soldering flux may be used alone or in combination of two or more.

[0072] The soldering flux preferably comprises an organic acid or an organic acid amine salt. The organic acid is preferably a dicarboxylic acid, and the organic acid amine salt is preferably a dicarboxylic acid amine salt. The soldering flux preferably comprises a dicarboxylic acid or a dicarboxylic acid amine salt, and more preferably comprises a dicarboxylic acid and a dicarboxylic acid amine salt.

[0073] Examples of the dicarboxylic acid include glutaric acid, adipic acid, azelaic acid, and pimelic acid.

[0074] Examples of the dicarboxylic acid amine salt include benzylamine glutarate, benzylamine adipate, benzylamine azelate, stearylamine glutarate, stearylamine adipate, and stearylamine azelate.

[0075] The soldering flux is preferably solid and may be spherical, or may be in a shape other than a spherical shape, or may be flat.

[0076] From the perspective of more effectively improving the ability to capture semiconductor chips flying at high speed using the laser transfer method, the flux preferably includes two or more fluxes having different numbers of carbon atoms in the main chain. From the perspective of more effectively improving the ability to capture semiconductor chips flying at high speed using the laser transfer method, the flux preferably includes a first flux having an even number of carbon atoms in the main chain and a second flux having an odd number of carbon atoms in the main chain. The first flux may be a single flux or a combination of two or more fluxes. The second flux may be a single flux or a combination of two or more fluxes.

[0077] The number of carbon atoms in the main chain of the first flux is an even number. The number of carbon atoms in the main chain of the first flux is an even number, and the number of carbon atoms in the main chain of the first flux is preferably 4 or more, more preferably 6 or more, preferably 14 or less, more preferably 12 or less, further preferably 10 or less, and particularly preferably 8 or less. The number of carbon atoms in the main chain of the first flux is preferably an even number of 4 or more and 14 or less. If the number of carbon atoms in the main chain of the first flux is greater than the lower limit and less than the upper limit, solder can be more efficiently placed on the electrode.

[0078] The second flux has an odd number of carbon atoms in its main chain. The second flux has an odd number of carbon atoms in its main chain, and the number of carbon atoms in its main chain is preferably 3 or more and 11 or less, more preferably 9 or less, and even more preferably 7 or less. The number of carbon atoms in its main chain is preferably an odd number of 3 or more and 11 or less. If the number of carbon atoms in its main chain is greater than or equal to the lower limit and less than or equal to the upper limit, solder can be more efficiently placed on the electrode.

[0079] The average particle size of the soldering flux (the average particle size of the entire soldering flux) is preferably 10 μm or less, more preferably 7 μm or less, further preferably 5 μm or less, and particularly preferably 3 μm or less. If the average particle size of the soldering flux is below the upper limit, the capture of semiconductor chips flying at high speed by the laser transfer method can be more effectively improved. The lower limit of the average particle size of the soldering flux is not particularly limited. The average particle size of the soldering flux can be 0.01 μm or more, 0.1 μm or more, 0.5 μm or more, or 1.0 μm or more. The range of the average particle size of the soldering flux can be set by appropriately selecting the lower limit value and the upper limit value.

[0080] The average particle size of the first soldering flux is preferably 10 μm or less, more preferably 7 μm or less, and further preferably 5 μm or less. If the average particle size of the first soldering flux is below the upper limit, the capture of semiconductor chips flying at high speed by the laser transfer method can be more effectively improved. The lower limit of the average particle size of the first soldering flux is not particularly limited. The average particle size of the first soldering flux can be greater than 0.5 μm, or greater than 1.0 μm. The range of the average particle size of the first soldering flux can be set by appropriately selecting the lower limit value and the upper limit value.

[0081] The average particle size of the second soldering flux is preferably 7 μm or less, more preferably 5 μm or less, and further preferably 3 μm or less. If the average particle size of the second soldering flux is below the upper limit, the capture of semiconductor chips flying at high speed by the laser transfer method can be more effectively improved. The lower limit of the average particle size of the second soldering flux is not particularly limited. The average particle size of the second soldering flux can be greater than 0.01 μm, or greater than 0.1 μm. The range of the average particle size of the second soldering flux can be set by appropriately selecting the lower limit value and the upper limit value.

[0082] The average particle size of the soldering flux and the average particle size of the first and second soldering fluxes are number average particle sizes. The average particle size of the soldering flux and the average particle size of the first and second soldering fluxes are obtained, for example, by observing any 50 soldering fluxes using an electron microscope or an optical microscope and calculating the average value of the particle size of each soldering flux; or by performing a laser diffraction particle size distribution measurement. In the observation under an electron microscope or an optical microscope, the particle size of each soldering flux is obtained as the particle size under the equivalent circle diameter. In the observation under an electron microscope or an optical microscope, the average particle size under the equivalent circle diameter of any 50 soldering fluxes is approximately equal to the average particle size under the equivalent sphere diameter. In the laser diffraction particle size distribution measurement, the particle size of each soldering flux is obtained as the particle size under the equivalent sphere diameter. The average particle size of the soldering flux and the average particle size of the first and second soldering fluxes are preferably calculated by laser diffraction particle size distribution measurement.

[0083] The soldering flux and the first and second soldering fluxes may be ground products of commercially available soldering fluxes. Examples of commercially available soldering flux grinding methods include agate mortar grinding, jet mill grinding, and bead mill grinding.

[0084] The coefficient of variation (CV value) of the particle size of the soldering flux (the coefficient of variation (CV value) of the particle size of the entire soldering flux) is preferably 10% or less, more preferably 5% or less. When the coefficient of variation of the particle size of the soldering flux is below the upper limit, the soldering flux can be more efficiently arranged on the electrode. The lower limit of the coefficient of variation (CV value) of the particle size of the soldering flux is not particularly limited. The coefficient of variation (CV value) of the particle size of the soldering flux can be 0% or more, 1% or more, or 5% or more. The range of the coefficient of variation of the particle size of the soldering flux can be set by appropriately selecting the lower limit and the upper limit.

[0085] The coefficient of variation (CV value) of the particle size of the flux can be measured as follows.

[0086] CV value (%) = (ρ / Dn) × 100

[0087] ρ: Standard deviation of flux particle size

[0088] Dn: Average value of flux particle size

[0089] The activation temperature (melting point) of the flux is preferably 50°C or higher, more preferably 70°C or higher, even more preferably 80°C or higher, preferably 200°C or lower, more preferably 190°C or lower, and even more preferably 180°C or lower. When the activation temperature of the flux is above the lower limit and below the upper limit, the flux effect is more effectively exerted, and the solder is more efficiently placed on the electrode. The activation temperature (melting point) of the flux is preferably 70°C or higher and 190°C or lower, and particularly preferably 80°C or higher and 180°C or lower.

[0090] The activation temperature (melting point) of the flux can be determined by differential scanning calorimetry (DSC). Examples of the differential scanning calorimetry (DSC) apparatus include "EXSTAR DSC7020" manufactured by SII Corporation.

[0091] Examples of the flux having an active temperature (melting point) of 80°C to 180°C include dicarboxylic acids such as glutaric acid (melting point 96°C), benzylamine glutarate (melting point 108°C), adipic acid (melting point 152°C), benzylamine adipate (melting point 180°C), pimelic acid (melting point 104°C), and suberic acid (melting point 142°C), benzoic acid (melting point 122°C), and malic acid (melting point 130°C).

[0092] Furthermore, the boiling point of the flux is preferably 200° C. or lower.

[0093] From the viewpoint of improving the coating and screen printing properties of the resin composition, the second flux is preferably soluble in the thixotropic agent at 25°C. The first flux may or may not be soluble in the thixotropic agent at 25°C. From the viewpoint of improving the coating and screen printing properties of the resin composition and improving the cohesion of the solder particles, the first flux is preferably insoluble in the thixotropic agent at 25°C, and the second flux is soluble in the thixotropic agent at 25°C. It should be noted that, in this specification, "the flux is soluble in the thixotropic agent" means that when 10g of the flux is placed in 20g of the thixotropic agent and kept at 25°C for 10 minutes, the weight of the flux dissolved in the thixotropic agent is more than 4g.

[0094] The soldering flux and the first and second soldering fluxes may be dispersed in the resin composition or attached to the surface of the solder particles. The second soldering flux may be dissolved in a thixotropic agent for use. The resin composition may contain the second soldering flux dissolved in a thixotropic agent.

[0095] From the perspective of more efficiently placing the solder on the electrode, the first flux is preferably 1,10-decanedicarboxylic acid, adipic acid, or a salt thereof, more preferably adipic acid or a salt thereof. From the perspective of more efficiently placing the solder on the electrode, the first flux is preferably 1,10-decanedicarboxylic acid or adipic acid, more preferably adipic acid.

[0096] From the perspective of more efficiently placing solder on the electrode, the second flux is preferably pimelic acid, azelaic acid, glutaric acid, or a salt thereof, more preferably azelaic acid, a salt thereof, glutaric acid, or a salt thereof. From the perspective of more efficiently placing solder on the electrode, the second flux is preferably pimelic acid, glutaric acid, or a salt thereof, more preferably glutaric acid or a salt thereof. From the perspective of more efficiently placing solder on the electrode, the second flux is preferably pimelic acid or glutaric acid, more preferably glutaric acid.

[0097] The flux is preferably one that releases cations upon heating. The first flux is preferably one that releases cations upon heating. The second flux is preferably one that releases cations upon heating. By using a flux that releases cations upon heating, solder can be more efficiently placed on the electrode.

[0098] In 100% by weight of the resin composition, the content of the flux (the content of the entire flux) is preferably 5% by weight or more, more preferably 10% by weight or more, further preferably 15% by weight or more, preferably 30% by weight or less, and more preferably 25% by weight or less. If the content of the flux is above the lower limit and below the upper limit, it is more difficult to form an oxide film on the surface of the solder and the electrode, and further, the oxide film formed on the surface of the solder and the electrode can be more effectively removed. It should be noted that, when the flux includes the first flux and the second flux, the content of the flux represents the sum of the content of the first flux and the content of the second flux (the same below).

[0099] The content of the first flux in 100% by weight of the resin composition is preferably 5% by weight or more, more preferably 8% by weight or more, and even more preferably 10% by weight or more, and is preferably 25% by weight or less, more preferably 20% by weight or less, and even more preferably 15% by weight or less. When the content of the first flux is above the lower limit and below the upper limit, good solder aggregation can be achieved.

[0100] The content of the second flux in 100% by weight of the resin composition is preferably 1% by weight or more, more preferably 2% by weight or more, and even more preferably 5% by weight or more, and preferably 25% by weight or less, more preferably 20% by weight or less, and even more preferably 15% by weight or less. When the content of the second flux is above the lower limit and below the upper limit, the coating and screen printing properties of the resin composition can be improved.

[0101] The content of the first flux in 100% by weight of the soldering flux is preferably 40% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, preferably 100% by weight or less, more preferably less than 100% by weight, even more preferably 90% by weight or less, particularly preferably 80% by weight or less, and most preferably 70% by weight or less. When the content of the first flux is above the lower limit and below the upper limit, the coating and screen printing properties of the resin composition can be improved.

[0102] The content of the soldering flux (the total content of the soldering flux) relative to 100 parts by weight of the thixotropic agent is preferably 100 parts by weight or more, more preferably 150 parts by weight or more, even more preferably 200 parts by weight or more, and preferably 500 parts by weight or less, more preferably 400 parts by weight or less, and even more preferably 300 parts by weight or less. When the content of the soldering flux is above the lower limit and below the upper limit, the coating and screen printing properties of the resin composition can be improved.

[0103] The content of the first flux is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, even more preferably 40 parts by weight or more, even more preferably 100 parts by weight or more, particularly preferably 150 parts by weight or more, and most preferably 200 parts by weight or more, preferably 500 parts by weight or less, more preferably 400 parts by weight or less, and even more preferably 300 parts by weight or less, relative to 100 parts by weight of the thixotropic agent. When the content of the first flux is above the lower limit and below the upper limit, the coating and screen printing properties of the resin composition can be improved.

[0104] The content of the second flux is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, and even more preferably 40 parts by weight or more, relative to 100 parts by weight of the thixotropic agent, and is preferably 100 parts by weight or less, more preferably 80 parts by weight or less, and even more preferably 60 parts by weight or less. When the content of the second flux is above the lower limit and below the upper limit, the coating and screen printing properties of the resin composition can be improved.

[0105] (Thixotropic agent)

[0106] The resin composition includes a thixotropic agent that is liquid at 25°C.

[0107] Examples of the thixotropic agent include ethylene glycol, diethylene glycol, 2-phenylethanol, 1,3-propylene glycol, and glycerin. The thixotropic agent may be used alone or in combination of two or more.

[0108] From the perspective of improving coating and screen printability, the thixotropic agent preferably comprises a polar compound, more preferably a compound having a hydroxyl group or a carboxyl group. From the perspective of improving coating and screen printability, the thixotropic agent preferably comprises ethylene glycol, diethylene glycol, 2-phenylethanol, 1,3-propylene glycol, or glycerol, more preferably ethylene glycol, 1,3-propylene glycol, or glycerol. From the perspective of improving coating and screen printability, the thixotropic agent particularly preferably comprises glycerol.

[0109] From the perspective of improving the coating and screen printing properties of the resin composition, the second flux preferably contains azelaic acid, a salt of azelaic acid, glutaric acid, or a salt of glutaric acid, and the thixotropic agent preferably contains glycerol or 1,3-propylene glycol. From the perspective of improving the coating and screen printing properties of the resin composition, the second flux is preferably azelaic acid, a salt of azelaic acid, glutaric acid, or a salt of glutaric acid, and the thixotropic agent is preferably glycerol or 1,3-propylene glycol. From the perspective of improving the coating and screen printing properties of the resin composition, the second flux preferably contains glutaric acid or a salt of glutaric acid, and the thixotropic agent preferably contains glycerol. From the perspective of improving the coating and screen printing properties of the resin composition, the second flux is preferably glutaric acid or a salt of glutaric acid, and the thixotropic agent is glycerol. From the perspective of improving the coating and screen printing properties of the resin composition, the second flux is preferably glutaric acid, and the thixotropic agent is glycerol.

[0110] From the perspective of improving the coating and screen printing properties of the resin composition, the resin composition particularly preferably contains azelaic acid, azelaic acid salt, glutaric acid, or a glutaric acid salt, and glycerol or 1,3-propylene glycol in a state where azelaic acid, azelaic acid salt, glutaric acid, or a glutaric acid salt is dissolved in glycerol or 1,3-propylene glycol. From the perspective of improving the coating and screen printing properties of the resin composition, the resin composition particularly preferably contains glutaric acid or a glutaric acid salt and glycerol in a state where glutaric acid or a glutaric acid salt is dissolved in glycerol. From the perspective of improving the coating and screen printing properties of the resin composition, the resin composition particularly preferably contains glutaric acid and glycerol in a state where glutaric acid is dissolved in glycerol.

[0111] The hydrogen bonding term δH in the Hansen solubility parameter of the thixotropic agent is preferably 10 MPa 1 / 2 More than 12 MPa 1 / 2 Above, more preferably 14 MPa 1 / 2 Above, particularly preferably 16 MPa 1 / 2 If the hydrogen bonding term δH in the Hansen solubility parameter of the thixotropic agent is greater than the lower limit, the coating and screen printing properties of the resin composition can be improved. The upper limit of the hydrogen bonding term δH in the Hansen solubility parameter of the thixotropic agent is not particularly limited. The hydrogen bonding term δH in the Hansen solubility parameter of the thixotropic agent may be 100 MPa. 1 / 2 Below, 50MPa is also possible 1 / 2 the following.

[0112] The hydrogen bonding term δH in the Hansen solubility parameters of the thixotropic agent can be easily calculated by using, for example, the computer software “Hansen Solubility Parameters in Practice (HSPiP)”.

[0113] In 100% by weight of the resin composition, the content of the thixotropic agent is preferably 1% by weight or more, more preferably 2% by weight or more, further preferably 3% by weight or more, preferably 20% by weight or less, more preferably 15% by weight or less, further preferably 10% by weight or less. When the content of the thixotropic agent is above the lower limit and below the upper limit, the coating and screen printing properties of the resin composition can be improved.

[0114] In 100% by weight of the resin composition, the content of glycerol is preferably 1% by weight or more, more preferably 2% by weight or more, and even more preferably 3% by weight or more, and preferably 20% by weight or less, more preferably 15% by weight or less, and even more preferably 10% by weight or less. When the content of glycerol is above the lower limit and below the upper limit, the coating and screen printing properties of the resin composition can be improved.

[0115] (Solder particles)

[0116] The resin composition contains solder particles. The center portion and outer surface of the solder particles are both formed of solder. The solder particles are particles whose center portion and outer surface are both solder. When the solder particles are replaced with conductive particles having substrate particles formed of a material other than solder and a solder portion arranged on the surface of the substrate particles, the conductive particles are less likely to gather on the electrode. In addition, since the solder bonding between the conductive particles is low among the conductive particles, there is a tendency for the conductive particles that have moved to the electrode to easily move outside the electrode.

[0117] The solder is preferably a metal (low-melting-point metal) having a melting point of 450°C or less. The solder particles are preferably metal particles (low-melting-point metal particles) having a melting point of 450°C or less. The low-melting-point metal particles are particles containing a low-melting-point metal. The low-melting-point metal refers to a metal having a melting point of 450°C or less. The melting point of the low-melting-point metal is preferably 300°C or less, more preferably 220°C or less, and even more preferably 190°C or less.

[0118] The melting point of the solder particles is preferably 100°C or higher, more preferably 105°C or higher, and preferably 250°C or lower, more preferably 245°C or lower. If the melting point of the solder particles is above the lower limit and below the upper limit, the cohesion of the solder during conductive connection can be more effectively improved. If the melting point of the solder particles is above the lower limit and below the upper limit, the conduction reliability and insulation reliability can be more effectively improved when electrically connecting electrodes.

[0119] The melting point of the solder particles can be determined by differential scanning calorimetry (DSC). Examples of the differential scanning calorimetry (DSC) apparatus include "EXSTAR DSC7020" manufactured by SII Corporation.

[0120] The solder particles preferably contain 90% by weight or more of solder per 100% by weight of the solder particles. Furthermore, the solder particles preferably contain tin. The tin content of 100% by weight of the metal contained in the solder particles is preferably 30% by weight or more, more preferably 40% by weight or more, further preferably 70% by weight or more, and particularly preferably 90% by weight or more. If the tin content in the solder particles is above the lower limit, the connection reliability between the solder portion and the electrode can be more effectively improved.

[0121] The tin content can be measured using a high-frequency inductively coupled plasma atomic emission spectrometer ("ICP-AES" manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer ("EDX-800 HS" manufactured by Shimadzu Corporation).

[0122] By using the solder particles, the solder melts and joins the electrodes, and the solder portion provides electrical continuity between the electrodes. For example, the solder portion and the electrode are in surface contact rather than point contact, thereby reducing connection resistance. Furthermore, by using the solder particles, the bonding strength between the solder portion and the electrode is increased, resulting in a reduction in separation between the solder portion and the electrode, thereby more effectively improving conduction reliability and connection reliability.

[0123] The low-melting-point metal constituting the solder particles is not particularly limited. The low-melting-point metal is preferably tin or an alloy containing tin. Examples of such alloys include tin-silver alloys, tin-copper alloys, tin-silver-copper alloys, tin-bismuth alloys, tin-zinc alloys, and tin-indium alloys. Due to their excellent wettability to the electrode, the low-melting-point metal is preferably tin, tin-silver alloys, tin-silver-copper alloys, tin-bismuth alloys, or tin-indium alloys. More preferably, the low-melting-point metal is a tin-bismuth alloy or a tin-indium alloy.

[0124] The solder particles are preferably a filler metal having a liquidus temperature of 450°C or lower, as defined in JIS Z3001: Soldering Terminology. Examples of the composition of the solder particles include metal compositions containing zinc, gold, silver, lead, copper, tin, bismuth, indium, and the like. The solder particles are preferably lead-free and preferably contain tin and indium, or tin and bismuth.

[0125] In order to further effectively improve the bonding strength between the solder portion and the electrode, the solder particles may also include metals such as nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, chromium, molybdenum and palladium. In addition, from the viewpoint of further improving the bonding strength between the solder portion and the electrode, the solder particles preferably include nickel, copper, antimony, aluminum or zinc. From the viewpoint of more effectively improving the bonding strength between the solder portion and the electrode, the content of these metals for improving the bonding strength is preferably 0.0001% by weight or more, preferably less than 1% by weight, in 100% by weight of the metal contained in the solder particles.

[0126] The average particle size of the solder particles is preferably 0.01 μm or greater, more preferably 0.03 μm or greater. If the average particle size of the solder particles is greater than the lower limit, the solder can be more efficiently arranged on the electrode. The average particle size of the solder particles may be 10 μm or less, 5 μm or less, or 3 μm or less. The range of the average particle size of the solder particles can be set by appropriately selecting the lower limit and the upper limit.

[0127] The average particle size of the solder particles is a number average particle size. The average particle size of the solder particles is obtained, for example, by observing any 50 solder particles using an electron microscope or an optical microscope, calculating the average value of the particle size of each solder particle, or performing laser diffraction particle size distribution measurement. In the observation using an electron microscope or an optical microscope, the particle size of each solder particle is obtained as the particle size under the equivalent circle diameter. In the observation using an electron microscope or an optical microscope, the average particle size under the equivalent circle diameter of any 50 solder particles is roughly equal to the average particle size under the equivalent sphere diameter. In the laser diffraction particle size distribution measurement, the particle size of each solder particle is obtained as the particle size under the equivalent sphere diameter. The average particle size of the solder particles is preferably calculated by laser diffraction particle size distribution measurement.

[0128] The coefficient of variation (CV) of the solder particle size is preferably 5% or greater, more preferably 10% or greater, preferably 40% or less, and more preferably 30% or less. If the coefficient of variation of the solder particle size is above the lower limit and below the upper limit, the solder can be more efficiently arranged on the electrode. However, the CV value of the solder particle size may be less than 5%.

[0129] The coefficient of variation (CV value) can be measured as follows.

[0130] CV value (%) = (ρ / Dn) × 100

[0131] ρ: Standard deviation of solder particle size

[0132] Dn: average solder particle size

[0133] The shape of the solder particles is not particularly limited and may be spherical, non-spherical, or flat.

[0134] In the resin combination 100% by weight, the content of the solder particles is preferably more than 1% by weight, more preferably more than 2% by weight, further preferably more than 10% by weight, particularly preferably more than 20% by weight, most preferably more than 30% by weight, preferably less than 80% by weight, more preferably less than 60% by weight, more preferably less than 50% by weight. If the content of the solder particles is more than the lower limit and less than the upper limit, solder can be more efficiently configured on the electrode, and solder can be easily configured in large quantities between the electrodes, so that conduction reliability can be more effectively improved. From the viewpoint of more effectively improving conduction reliability, the content of the preferably solder particles is many.

[0135] (Other ingredients)

[0136] The resin composition may contain various additives such as fillers, extenders, softeners, plasticizers, thickeners, leveling agents, polymerization catalysts, curing catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, lubricants, antistatic agents and flame retardants as needed.

[0137] (Connected structure and method for manufacturing the connected structure)

[0138] The connection structure of the present invention comprises: a first connection member having a first electrode on its surface; a second connection member having a second electrode on its surface; and a connection portion connecting the first and second connection members. In the connection structure of the present invention, the material of the connection portion is the resin composition. In the connection structure of the present invention, the first and second electrodes are electrically connected via a solder portion in the connection portion.

[0139] In the connection structure of the present invention, due to the use of a specific resin composition, the solder is easily gathered between the first electrode and the second electrode, and the solder can be efficiently configured on the electrode (line). In addition, a part of the solder is not easily configured in the area (space) where the electrode is not formed, and the amount of solder configured in the area where the electrode is not formed can be quite small. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. Moreover, the electrical connection between the adjacent electrodes in the lateral direction that cannot be connected can be prevented, and the insulation reliability can be improved.

[0140] Furthermore, in order to efficiently arrange the solder on the electrodes and to minimize the amount of solder arranged in regions where no electrodes are formed, it is preferable to use a conductive paste rather than a conductive film as the resin composition.

[0141] In the connection structure, the first connection target member is preferably a circuit board. In the connection structure, the second connection target member is preferably a semiconductor chip.

[0142] The method for manufacturing a connection structure of the present invention comprises the following steps. (1) a first configuration step, which uses the resin composition to configure the resin composition on the surface of a first connection object member having at least one first electrode on the surface. (2) a second configuration step, which moves the second connection object member having at least one second electrode on the surface to the surface of the resin composition opposite to the first connection object member by a laser transfer method, and configures the second connection object member in a manner such that the first electrode and the second electrode are opposed to each other. (3) a connection step, which forms a connection portion for connecting the first connection object member and the second connection object member using the resin composition by heating the resin composition to a temperature above the melting point of the solder particles, and electrically connects the first electrode and the second electrode through the solder portion in the connection portion.

[0143] In the method for manufacturing a connection structure of the present invention, since the above-mentioned configuration is provided, it is possible to improve the ability to capture the second connection target member (semiconductor chip) that flies at high speed by the laser transfer method.

[0144] Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0145] Figure 1 This is a cross-sectional view schematically showing a connection structure obtained using the resin composition according to one embodiment of the present invention.

[0146] Figure 1 The connection structure 1 shown includes a first connection target member 2, a second connection target member 3, and a connection portion 4 that connects the first connection target member 2 and the second connection target member 3. The connection portion 4 is formed from the resin composition.

[0147] In this embodiment, the resin composition includes a thermosetting component, a flux, a thixotropic agent that is liquid at 25° C., and solder particles. In this embodiment, a conductive paste is used as the resin composition.

[0148] The connection portion 4 includes a solder portion 4A formed by a plurality of solder particles aggregated and bonded to each other, and a cured product portion 4B formed by thermally curing a thermosetting component.

[0149] The first connection object member 2 has a plurality of first electrodes 2a on the surface (upper surface). The second connection object member 3 has a plurality of second electrodes 3a on the surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected via the solder portion 4A. Therefore, the first connection object member 2 and the second connection object member 3 are electrically connected via the solder portion 4A. It should be noted that, in the connection portion 4, there is no solder in an area (solidified portion 4B portion) different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a. There is no solder separated from the solder portion 4A in an area (solidified portion 4B portion) different from the solder portion 4A. It should be noted that, if it is a small amount, solder may also be present in an area (solidified portion 4B portion) different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a.

[0150] like Figure 1 As shown, in the connection structure 1, multiple solder particles gather between the first electrode 2a and the second electrode 3a. After the multiple solder particles melt, the molten material of the solder particles infiltrates and spreads on the surface of the electrode and then solidifies to form a solder portion 4A. Therefore, the connection area between the solder portion 4A and the first electrode 2a, and the solder portion 4A and the second electrode 3a becomes larger. That is, by using solder particles, the contact area between the solder portion 4A and the first electrode 2a, and the solder portion 4A and the second electrode 3a becomes larger than when using conductive particles whose outer surface portion of the conductive portion is a metal such as nickel, gold or copper. Therefore, the conduction reliability and connection reliability of the connection structure 1 become higher. It should be noted that the flux and thixotropic agent contained in the resin composition are usually gradually inactivated by heating.

[0151] It should be noted that in Figure 1 In the connection structure 1 shown, the solder portion 4A is entirely located in the opposing region between the first and second electrodes 2 a and 3 a . Figure 5 The connection structure 1X of the modified example shown only connects the connection portion 4X and Figure 1 The connection structure 1 shown is different. The connection portion 4X has a solder portion 4XA and a solidified material portion 4XB. As in the connection structure 1X, most of the solder portion 4XA may be located in the opposing regions of the first and second electrodes 2a and 3a, and a portion of the solder portion 4XA may extend laterally from the opposing regions of the first and second electrodes 2a and 3a. The solder portion 4XA extending laterally from the opposing regions of the first and second electrodes 2a and 3a is a portion of the solder portion 4XA and is not solder separated from the solder portion 4XA. It should be noted that in this embodiment, the amount of solder away from the solder portion can be reduced, but solder away from the solder portion may also exist in the solidified material portion.

[0152] When the amount of solder particles used is reduced, it is easy to obtain the connection structure 1. When the amount of solder particles used is increased, it is easy to obtain the connection structure 1X.

[0153] The thickness of the solder portion between the first electrode and the second electrode is preferably 10 μm or more, more preferably 20 μm or more, preferably 100 μm or less, and more preferably 80 μm or less. In the first electrode and the second electrode, the solder wetted area on the surface of the electrode (the area of ​​solder contact out of 100% of the exposed area of ​​the electrode) is preferably 50% or more, more preferably 60% or more, further preferably 70% or more, and preferably 100% or less. By making the solder portion in the connecting portion meet the above preferred embodiment, the conduction reliability and insulation reliability can be more effectively improved.

[0154] In the connection structure 1, 1X, it is preferred that the solder portion 4A, 4XA of the connection portion 4, 4X is disposed in 50% or more of 100% of the area of ​​the mutually opposing portion of the first electrode 2a and the second electrode 3a, when viewed in the stacking direction of the first electrode 2a, the connection portion 4, 4X, and the second electrode 3a. By ensuring that the solder portion 4A, 4XA of the connection portion 4, 4X satisfies this preferred configuration, conductive reliability can be further improved.

[0155] When the mutually opposing portion of the first electrode and the second electrode is viewed in the direction in which the first electrode, the connecting portion, and the second electrode are stacked, the solder portion in the connecting portion is preferably disposed over 50% of 100% of the area of ​​the mutually opposing portion of the first electrode and the second electrode. When the mutually opposing portion of the first electrode and the second electrode is viewed in the direction in which the first electrode, the connecting portion, and the second electrode are stacked, the solder portion in the connecting portion is more preferably disposed over 60% of 100% of the area of ​​the mutually opposing portion of the first electrode and the second electrode. When the mutually opposing portion of the first electrode and the second electrode is viewed in the direction in which the first electrode, the connecting portion, and the second electrode are stacked, the solder portion in the connecting portion is further preferably disposed over 70% of 100% of the area of ​​the mutually opposing portion of the first electrode and the second electrode. When the mutually opposing portion of the first electrode and the second electrode is viewed in the direction in which the first electrode, the connecting portion, and the second electrode are stacked, the solder portion in the connecting portion is particularly preferably disposed over 80% of 100% of the area of ​​the mutually opposing portion of the first electrode and the second electrode. When the mutually opposing portions of the first electrode and the second electrode are viewed in the stacking direction of the first electrode, the connecting portion, and the second electrode, it is most preferred that the solder portion in the connecting portion be disposed over 90% or more of 100% of the area of ​​the mutually opposing portions of the first electrode and the second electrode. By ensuring that the solder portion in the connecting portion satisfies this preferred configuration, conduction reliability can be further improved.

[0156] When observing the mutually opposing portions of the first electrode and the second electrode in a direction perpendicular to the stacking direction of the first electrode, the connecting portion, and the second electrode, it is preferred that 60% or more of the solder portion in the connecting portion is disposed in the mutually opposing portions of the first electrode and the second electrode. When observing the mutually opposing portions of the first electrode and the second electrode in a direction perpendicular to the stacking direction of the first electrode, the connecting portion, and the second electrode, it is more preferred that 70% or more of the solder portion in the connecting portion is disposed in the mutually opposing portions of the first electrode and the second electrode. When observing the mutually opposing portions of the first electrode and the second electrode in a direction perpendicular to the stacking direction of the first electrode, the connecting portion, and the second electrode, it is further preferred that 90% or more of the solder portion in the connecting portion is disposed in the mutually opposing portions of the first electrode and the second electrode. When observing the mutually opposing portions of the first electrode and the second electrode in a direction perpendicular to the stacking direction of the first electrode, the connecting portion, and the second electrode, it is particularly preferred that 95% or more of the solder portion in the connecting portion is disposed in the mutually opposing portions of the first electrode and the second electrode. When the mutually opposing portions of the first electrode and the second electrode are viewed in a direction perpendicular to the stacking direction of the first electrode, the connecting portion, and the second electrode, it is most preferred that at least 99% of the solder portion of the connecting portion is disposed in the mutually opposing portions of the first electrode and the second electrode. By ensuring that the solder portion of the connecting portion satisfies this preferred configuration, conduction reliability can be further improved.

[0157] Next, refer to Figures 2 to 4 An example of a method for producing the connection structure 1 using the resin composition according to one embodiment of the present invention will be described. Figures 2 to 4 These are cross-sectional views for explaining each step of an example of a method for producing a connection structure using the resin composition according to one embodiment of the present invention.

[0158] First, prepare a first connection object member (circuit board) 2 having a first electrode 2a on its surface (upper surface). Figure 2 As shown, a resin composition 11 containing a thermosetting component 11B, solder particles 11A, flux 11C, and a thixotropic agent (not shown) that is liquid at 25° C. is disposed on the surface of the first connection target member (circuit board) 2 (first disposing step). The thermosetting component 11B contains a thermosetting compound.

[0159] A resin composition 11 is placed on the surface of the first connection target member (circuit board) 2, where the first electrode 2a is provided. After the resin composition 11 is placed, solder particles 11A, flux 11C, and a thixotropic agent are placed both on the first electrode 2a (line) and in the area (space) where the first electrode 2a is not formed. It should be noted that the resin composition may be placed only on the surface of the first electrode.

[0160] There are no particular limitations on the method for disposing the resin composition 11. Examples of the method for disposing the resin composition 11 include coating with a dispenser, screen printing, and discharge with an inkjet device.

[0161] Separately, a second connection target member (semiconductor chip) 3 having a second electrode 3a on its surface (lower surface) is prepared. The second connection target member (semiconductor chip) 3 having the second electrode 3a on its surface (lower surface) is placed on the support film 6 side of a transfer source substrate having a support member 5 and a support film 6. The second connection target member (semiconductor chip) 3 having the second electrode 3a on its surface (lower surface) is placed on the surface of the support film 6.

[0162] Then, if Figure 3 As shown, in the resin composition 11 on the surface of the first connection object member (circuit substrate) 2, the second connection object member (semiconductor chip) 3 is moved to the surface of the resin composition 11 on the side opposite to the first connection object member (circuit substrate) 2 by a laser transfer method, and the second connection object member (semiconductor chip) 3 is arranged (second arrangement process). On the surface of the resin composition 11, the second connection object member (semiconductor chip) 3 is arranged from the second electrode 3a side. In the second arrangement process, by irradiating the laser from the support member 5 side of the transfer source substrate using a laser irradiation device 51, the curing reaction of the curable component (resin component) in the support film 6 proceeds, and the adhesive force of the surface of the support film 6 is greatly reduced. As a result, the second connection object member (semiconductor chip) 3 is peeled off from the transfer source substrate (particularly the support film 6) and moved to the surface of the resin composition 11 on the side opposite to the first connection object member (circuit substrate) 2 side. The second connection target member (semiconductor chip) 3 is moved by itself, for example, while its surface is not in contact with other members (not held by other members). At this time, the first electrode 2a and the second electrode 3a are opposed to each other.

[0163] In this embodiment, the use of the resin composition improves the ability to capture the second connection target member (semiconductor chip) 3 flying at high speed by the laser transfer method during the second placement step. As a result, the flying second connection target member (semiconductor chip) can be accurately placed at a predetermined location on the first connection target member (circuit board) (effectively suppressing positional deviation of the semiconductor chip during placement).

[0164] Next, the resin composition 11 is heated to a temperature above the melting point of the solder particles 11A. The resin composition 11 is preferably heated to a temperature above the curing temperature of the thermosetting component 11B (thermosetting compound). During this heating, the solder particles 11A present in the area where no electrode is formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). In the case of using a conductive paste instead of a conductive film, the solder particles 11A gather more effectively between the first electrode 2a and the second electrode 3a. In addition, the solder particles 11A melt and join to each other. In addition, the thermosetting component 11B is thermally cured. As a result, as Figure 4 As shown, a connection portion 4 connecting a first connection target member (circuit board) 2 and a second connection target member (semiconductor chip) 3 is formed from a resin composition 11. The connection portion 4 is formed from the resin composition 11, a plurality of solder particles 11A are joined to form a solder portion 4A, a thermosetting component 11B is thermally cured to form a cured portion 4B, and the first electrode 2a and the second electrode 3a are electrically connected via the solder portion 4A in the connection portion 4 (connection step). If the solder particles 11A are sufficiently mobile, the temperature need not be maintained constant from the start of movement of solder particles 11A not located between the first electrode 2a and the second electrode 3a until the completion of movement of the solder particles 11A between the first electrode 2a and the second electrode 3a.

[0165] Preferably, no pressure is applied during the second placement step and the connection step. In this case, the weight of the second connection target member (semiconductor chip) 3 is applied to the resin composition 11. Therefore, when forming the connection portion 4, the solder particles 11A are more effectively gathered between the first electrode 2a and the second electrode 3a. It should be noted that if pressure is applied during at least one of the second placement step and the connection step, the tendency of the solder particles 11A to be hindered from gathering between the first electrode 2a and the second electrode 3a is increased.

[0166] In addition, in this embodiment, since no pressure is applied, even if the alignment of the first electrode 2a and the second electrode 3a is slightly offset, even if the first connection object member (circuit board) 2 and the second connection object member (semiconductor chip) 3 overlap, this slight offset can be corrected to connect the first electrode 2a and the second electrode 3a (self-alignment effect). This is because the molten solder that self-condenses between the first electrode 2a and the second electrode 3a becomes energetically stable when the area of ​​contact between the solder and the other components of the resin composition between the first electrode 2a and the second electrode 3a is minimized, and the force of the aligned connection structure with the minimum area is exerted. At this time, it is preferred that the resin composition is uncured and that the viscosity of the components of the resin composition other than the solder particles is sufficiently low at this temperature and time.

[0167] In this way, we get Figure 1 The connected structure 1 shown in FIG. It should be noted that the second placement step and the connecting step can also be performed continuously. Alternatively, after the second placement step, the laminate of the first connection target member 2, the resin composition 11, and the second connection target member 3 can be moved to a heating unit to perform the connecting step. To perform the heating, the laminate can be placed on a heating unit or in a heated space.

[0168] In the second configuration step, the second connection object member is preferably moved to the surface of the resin composition opposite to the first connection object member side by a laser transfer method at a speed of 1 cm / s or more, and the second connection object member is configured in a manner that the first electrode and the second electrode are opposed to each other. In the second configuration step, the second connection object member is preferably moved to the surface of the resin composition opposite to the first connection object member side by a laser transfer method at a speed of 5 cm / s or more, more preferably 10 cm / s or more, and further preferably 50 cm / s or more. The upper limit of the speed at which the second connection object member is moved by the laser transfer method is not particularly limited. In the laser transfer method in the second configuration step, the second connection object member may also be moved to the surface of the resin composition opposite to the first connection object member side at a speed of 500 cm / s or less. In the second configuration step, the range of the speed at which the second connection object member is moved to the surface of the resin composition opposite to the first connection object member side by the laser transfer method can be set by appropriately selecting the lower limit and the upper limit.

[0169] The heating temperature in the connecting step is preferably 250° C. or higher, more preferably 300° C. or higher, preferably 450° C. or lower, more preferably 400° C. or lower, and even more preferably 350° C. or lower. If the heating temperature in the connecting step is above the lower limit and below the upper limit, solder can be more efficiently placed on the electrodes, and the electrical conduction reliability between the upper and lower electrodes to be connected can be more effectively improved.

[0170] Examples of the heating method in the connection step include a method of heating the entire connection structure to a temperature above the melting point of the solder and the curing temperature of the thermosetting component using a reflow furnace or an oven, and a method of locally heating only the connection portion of the connection structure to a temperature above the melting point of the solder and the curing temperature of the thermosetting component.

[0171] As an instrument used in the local heating method, a hot plate, a heat gun for applying hot air, a soldering iron, an infrared heater, etc. are mentioned.

[0172] When using a hot plate for local heating, the upper surface of the hot plate is preferably formed as follows: the portion immediately below the connection is formed of a metal with high thermal conductivity, and other portions not preferably heated are formed of a material with low thermal conductivity such as fluororesin.

[0173] The first and second connection objects are not particularly limited. Examples of the first and second connection objects include electronic components such as semiconductor chips, semiconductor packages, capacitors, and diodes, as well as electronic components such as circuit substrates such as resin films, printed circuit boards, flexible printed circuit boards, flexible flat cables, rigid-flexible substrates, glass epoxy substrates, and glass substrates. The semiconductor chip may be an LED chip, and the semiconductor package may be an LED package. The second connection object is preferably an electronic component. The second connection object is preferably a semiconductor chip, more preferably an LED chip, and even more preferably a micro-LED chip.

[0174] At least one of the first connection object member and the second connection object member is preferably a resin film, a flexible printed substrate, a flexible flat cable or a rigid-flexible substrate. The first connection object member is preferably a resin film, a flexible printed substrate, a flexible flat cable or a rigid-flexible substrate. Resin film, flexible printed substrate, flexible flat cable and rigid-flexible substrate have the properties of high flexibility and relatively light weight. When a conductive film is used in the connection of such connection object members, there is a tendency for solder to be difficult to accumulate on the electrodes. In contrast, by using a conductive paste, even if a resin film, a flexible printed substrate, a flexible flat cable or a rigid-flexible substrate is used, the conduction reliability between the electrodes can be substantially improved by efficiently accumulating solder on the electrodes.

[0175] As the electrode provided on the connection object member, metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS electrodes and tungsten electrodes can be cited. When the connection object member is a flexible printed substrate, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode or a copper electrode. When the connection object member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode or a tungsten electrode. It should be noted that when the electrode is an aluminum electrode, it can be an electrode formed only of aluminum, or it can be an electrode having an aluminum layer laminated on the surface of a metal oxide layer. As the material of the metal oxide layer, indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element can be cited. As the trivalent metal element, Sn, Al and Ga can be cited.

[0176] The supporting member is not particularly limited and examples of the supporting member include a glass substrate, a sapphire substrate, a polysiloxane substrate, a metal substrate, and an organic substrate.

[0177] The support film is not particularly limited. Examples of the support film include silicone resin films, acrylic resin films, and polyimide resin films. The support film preferably has an adhesive layer.

[0178] In the second placement step, the cumulative light intensity of the irradiated laser light is preferably 100 mJ / cm 2 More than 150 mJ / cm 2 More than 200 mJ / cm 2 Above, preferably 400mJ / cm 2 Below, more preferably 350mJ / cm 2 Below, more preferably 300mJ / cm 2 If the cumulative light quantity of the laser light irradiated in the second placement step is equal to or greater than the lower limit and equal to or less than the upper limit, the ability to capture semiconductor chips flying at high speed can be further improved.

[0179] The present invention will be described in detail below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[0180] Thermosetting ingredients (thermosetting compounds):

[0181] Phenol novolac-type epoxy compound ("JER152" manufactured by Mitsubishi Chemical Corporation)

[0182] Bisphenol F epoxy compound (DIC Corporation "830-S")

[0183] Flux:

[0184] Benzylamine adipate (first flux (main chain carbon number 4), average particle size 10 μm, melting point 180°C, prepared according to Synthesis Example 1 below)

[0185] Benzylamine glutarate (second flux (main chain carbon number 3), average particle size 10 μm, melting point 108°C, prepared according to Synthesis Example 2 below)

[0186] Azelaic acid stearylamine salt (second flux (main chain carbon number 7), average particle size 10 μm, melting point 110°C, prepared according to Synthesis Example 3 below)

[0187] Synthesis example 1:

[0188] 24 g of water and 14.612 g of adipic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a glass bottle as a reaction solvent and heated at 100°C for 10 minutes to dissolve the mixture. 10.715 g of benzylamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was then added and stirred for approximately 5 minutes to obtain a mixed solution. The resulting mixed solution was placed in a refrigerator at 5°C to 10°C and allowed to stand overnight. The precipitated crystals were separated by filtration, washed with water, and vacuum-dried to obtain benzylamine adipate (average particle size 30 μm). The obtained benzylamine adipate was pulverized by jet milling to obtain benzylamine adipate with an average particle size of 10 μm.

[0189] Synthesis example 2:

[0190] 24 g of water and 13.212 g of glutaric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a glass bottle as a reaction solvent and dissolved at room temperature until uniform. Then, 10.715 g of benzylamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added and stirred for approximately 5 minutes to obtain a mixed solution. The resulting mixed solution was placed in a refrigerator at 5°C to 10°C and allowed to stand overnight. The precipitated crystals were separated by filtration, washed with water, and vacuum-dried to obtain benzylamine glutarate. The obtained benzylamine glutarate was pulverized by jet milling to obtain benzylamine glutarate with an average particle size of 10 μm.

[0191] Synthesis example 3:

[0192] 24 g of water and 9.411 g of azelaic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a glass bottle as a reaction solvent and heated at 100°C for 10 minutes to dissolve. Then, 13.476 g of stearylamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added and stirred for approximately 5 minutes to obtain a mixed solution. The resulting mixed solution was placed in a refrigerator at 5°C to 10°C and allowed to stand overnight. The precipitated crystals were separated by filtration, washed with water, and vacuum-dried to obtain stearylamine azelaic acid salt (average particle size 30 μm). The obtained stearylamine azelaic acid salt was pulverized using a jet mill to obtain benzylamine adipate salt with an average particle size of 10 μm.

[0193] Thixotropic agent with dissolved flux:

[0194] A thixotropic agent containing glutaric acid dissolved in glycerol ("Glycerol" manufactured by Nacalai Tesque Co., Ltd., 30% by weight of glutaric acid and 70% by weight of glycerol, with the hydrogen bonding term δH in the Hansen solubility parameter of glycerol being 14.3 MPa) 1 / 2 )

[0195] Thixotropic agent:

[0196] Ethylene glycol (manufactured by Wako, liquid at 25°C, hydrogen bonding term δH in Hansen solubility parameter 12.7 MPa) 1 / 2 )

[0197] 1,3-Propanediol (produced by TCI, liquid at 25°C, hydrogen bonding term δH in Hansen solubility parameter 12.9 MPa) 1 / 2 )

[0198] Solder particles:

[0199] SnAgCu solder particles (screened: melting point 220°C, "Sn96.5Ag3Cu0.5" manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size 3 μm)

[0200] SnBi solder particles (screened from "Sn42Bi58" solder particles with a melting point of 139°C, manufactured by Mitsui Mining & Smelting Co., Ltd., with an average particle size of 3 μm)

[0201] (Average particle size of flux and solder particles)

[0202] The average particle diameters of the flux and solder particles were measured using a laser diffraction particle size distribution analyzer ("LA-920" manufactured by Horiba, Ltd.).

[0203] (Melting point of solder particles and flux)

[0204] The melting points of the solder particles and the flux were calculated using differential scanning calorimetry (DSC). As a differential scanning calorimetry (DSC) apparatus, "EXSTAR DSC7020" manufactured by SII Corporation was used.

[0205] (Examples 1 to 8 and Comparative Examples 1 to 2)

[0206] (1) Preparation of resin composition (anisotropic conductive paste)

[0207] The components shown in Tables 1 to 3 below were blended in the blending amounts shown in Tables 1 to 3 below to obtain resin compositions (anisotropic conductive pastes).

[0208] (2) Fabrication of the connection structure

[0209] As a first connection object member (circuit board), a glass substrate (thickness: 0.7 mm) having a plurality of electrodes (first electrodes, copper electrodes 23 μm wide × 30 μm long × 12 μm thick, with a 14 μm inter-electrode space) on its surface was prepared.

[0210] As the second connection object component (semiconductor chip), a micro LED chip (material: GaN, thickness: 0.01 mm) having multiple electrodes on the surface (second electrode, gold electrode with a horizontal size of 20 μm × a vertical size of 20 μm × a thickness of 3 μm, and a space of 10 μm between electrodes) was prepared.

[0211] On the upper surface of the glass substrate, a resin composition (anisotropic conductive paste) just produced is applied by screen printing in a manner to a thickness of 10 μm to form a resin composition (anisotropic conductive paste) layer. Next, semiconductor chips are stacked on the upper surface of the resin composition (anisotropic conductive paste) layer by a laser transfer method in a manner such that the electrodes are opposite to each other. From this state, the temperature of the resin composition (anisotropic conductive paste) layer is heated in a manner such that it becomes the melting point of the solder particles 5 seconds after the start of heating. Furthermore, the temperature of the resin composition (anisotropic conductive paste) layer is heated in a manner such that it becomes 250°C 10 seconds after the start of heating, so that the resin composition (anisotropic conductive paste) layer is cured to obtain a connection structure. During heating, no pressure is applied.

[0212] (evaluate)

[0213] (1) Contact angle with respect to water at 25°C

[0214] The contact angle of the obtained resin composition with respect to water at 25° C. was measured by the above-mentioned method.

[0215] (2) Screen printing (coating)

[0216] The resulting resin composition (anisotropic conductive paste) was screen-printed onto a glass substrate using a metal mask with openings measuring 114 μm x 60 μm per pattern and a thickness of 10 μm. The printed surface of 50 patterns immediately after printing was observed using a laser microscope, and the volume of the resin composition applied to the glass substrate was calculated. The ratio (X%) of the volume of the resin composition applied to the glass substrate relative to the volume of each opening in the metal mask was also calculated. Screen printability was evaluated according to the following criteria.

[0217] [Criteria for Screen Printability]

[0218] ○○: Ratio X is 50% or more

[0219] ○: Ratio X is 40% or more and less than 50%

[0220] △: Ratio X is 30% or more and less than 40%

[0221] ×: Ratio X is less than 30%

[0222] (3) Solder cohesion

[0223] In the resulting connection structures (20), the ratio of the area of ​​the solder portion of the connection portion to the total area of ​​the first and second electrodes, based on the stacking direction of the first electrode, the connection portion, and the second electrode, was evaluated. The 20 values ​​were averaged to determine the area ratio Y. Based on the area ratio Y, the cohesion of the solder during the conductive connection was determined according to the following criteria.

[0224] [Criteria for Determining Solder Cohesion]

[0225] ○○: Ratio Y is 70% or more

[0226] ○: Ratio Y is 60% or more and less than 70%

[0227] △: Ratio Y is 50% or more and less than 60%

[0228] ×: Ratio Y is less than 50%

[0229] (4) Capturing properties of semiconductor chips

[0230] In "(2) Screen Printability," a semiconductor chip was transferred at a speed of 1 cm / s onto the surface of a resin composition applied to a glass substrate by screen printing. Twenty semiconductor chips were arranged so that the first electrode of the glass substrate and the second electrode of the semiconductor chip faced each other. The proportion Z of the 20 semiconductor chips captured within ±3 μm of the specified position was calculated. The semiconductor chip capture performance was evaluated according to the following criteria.

[0231] [Criteria for determining the capture performance of semiconductor chips]

[0232] ○○: Ratio Z is 70% or more

[0233] ○: Ratio Z is 50% or more and less than 70%

[0234] ×: Ratio Z is less than 50%

[0235] The results are shown in Tables 1 to 3 below.

[0236] [Table 1]

[0237]

[0238] [Table 2]

[0239]

[0240] [Table 3]

[0241] BRIEF DESCRIPTION OF THE DRAWINGS

[0242] 1. 1X…connection structure

[0243] 2...First connection partner member (circuit board)

[0244] 2a…first electrode

[0245] 3...Second connection target member (semiconductor chip)

[0246] 3a…Second electrode

[0247] 4. 4X…connection

[0248] 4A, 4XA…Solder

[0249] 4B…4XB…cured material part

[0250] 5…Supporting member (transfer source substrate)

[0251] 6…Support film (transfer source substrate)

[0252] 11…resin composition

[0253] 11A…Solder particles

[0254] 11B…Thermosetting component

[0255] 11C…Flux

[0256] 51…Laser irradiation device

Claims

1. A resin composition comprising: Thermosetting components, flux, Thixotropic agents that are liquid at 25°C, and Solder particles.

2. The resin composition according to claim 1, wherein The soldering flux comprises: The first flux having an even number of carbon atoms in the main chain, and The second flux has an odd number of carbon atoms in the main chain.

3. The resin composition according to claim 2, wherein The hydrogen bonding term δH in the Hansen solubility parameter of the thixotropic agent is 10 MPa 1 / 2 above, The number of carbon atoms in the main chain of the first soldering flux is an even number of 4 or more and 14 or less, The second flux has an odd number of carbon atoms in its main chain of 3 or more and 11 or less.

4. The resin composition according to claim 2 or 3, wherein The average particle size of the first soldering flux is 10 μm or less.

5. The resin composition according to any one of claims 2 to 4, wherein The second soldering flux can be dissolved in the thixotropic agent at 25°C.

6. The resin composition according to any one of claims 2 to 5, wherein In 100 wt % of the resin composition, the content of the second flux is 1 wt % or more and 20 wt % or less.

7. The resin composition according to any one of claims 1 to 6, wherein The thixotropic agent comprises glycerin.

8. The resin composition according to any one of claims 1 to 7, wherein The content of the flux in 100 wt % of the resin composition is 5 wt % or more and 25 wt % or less.

9. The resin composition according to any one of claims 1 to 8, wherein The average particle size of the solder particles is 10 μm or less.

10. A method for manufacturing a connection structure, comprising: a first placement step of using the resin composition according to any one of claims 1 to 9 and placing the resin composition on a surface of a first connection target member having at least one first electrode on its surface; a second placement step of moving a second connection member having at least one second electrode on its surface to a surface of the resin composition opposite to the first connection member by laser transfer, and placing the second connection member so that the first electrode and the second electrode face each other; as well as The connecting step includes heating the resin composition to a temperature equal to or higher than the melting point of the solder particles to form a connecting portion for connecting the first connection target member and the second connection target member using the resin composition, and electrically connecting the first electrode and the second electrode via the solder portion in the connecting portion.

11. The method for manufacturing a connection structure according to claim 10, wherein: In the second placement step, the second connection member is moved by laser transfer at a speed of 1 cm / s or more onto the surface of the resin composition opposite to the first connection member, and the second connection member is placed so that the first electrode and the second electrode face each other.

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