CN120604303A - Resin composition and method for producing connection structure - Google Patents

Abstract

The invention provides a resin composition (11) capable of improving the capturing property of a semiconductor chip (3) flying at high speed. The resin composition (11) of the present invention comprises a thermosetting component (11B), a flux (11C), a thixotropic agent that is liquid at 25 ℃ and solder particles (11A).

Description

Resin composition and method for producing connection structure

Technical Field

The present invention relates to a resin composition containing solder particles. The present invention also relates to a method for producing a connection structure using the resin composition.

Background

Anisotropic conductive materials such as anisotropic conductive paste and anisotropic conductive film are well known. In the anisotropic conductive material, conductive particles are dispersed in a binder. As the conductive particles, solder particles are widely used.

The anisotropic conductive material is used to obtain various connection structures. Examples of the connection of the anisotropic conductive material include connection (FOG (Film on Glass)) of the flexible printed circuit board and the glass substrate, connection (COF (Chip on Film)) of the semiconductor chip and the flexible printed circuit board, connection (COG (Chip on Glass)) of the semiconductor chip and the glass substrate, and connection (FOB (Film on Board)) of the flexible printed circuit board and the glass epoxy substrate.

In recent years, miniaturization and weight reduction of devices using connection structures have been advanced. In response to this, development of a connection structure using a micro LED (micro-LIGHT EMITTING diode) chip or other fine semiconductor chip has been demanded. As a method of disposing a fine semiconductor chip such as a micro LED chip on a circuit board, a laser transfer method has been attracting attention.

Patent document 1 discloses a laser transfer device. In this laser transfer apparatus, a transfer source substrate having a plurality of elements formed thereon is disposed above a transfer target substrate. The transfer source substrate is irradiated with laser light from above to move down a plurality of transfer target elements, which are transfer targets, among the plurality of elements, and the transfer target elements are transferred to the transfer target substrate.

Patent document 2 below discloses a transfer method for transferring a chip member held on a transfer substrate via a photocurable adhesive layer to a transfer target substrate. The transfer method includes an exposure step of pattern-exposing the adhesive layer with light having a wavelength at which the adhesive layer is cured, thereby locally reducing the adhesive force of the adhesive layer, and a laser lift-off step of transferring the chip member to the transfer target substrate by a laser lift-off method after the exposure step.

Prior art literature

Patent literature

Patent document 1 WO2020/188780A1

Patent document 2 Japanese patent application laid-open No. 2020-53558

Disclosure of Invention

Technical problem to be solved by the invention

In the method of arranging semiconductor chips using the laser transfer method, 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), and therefore, the productivity of the connection structure can be improved.

However, in the method of disposing the semiconductor chip using the laser transfer method, the semiconductor chip may not be disposed accurately at a predetermined portion on the circuit board (the member to be connected) due to an impact when the semiconductor chip flying at high speed lands on the circuit board (the member to be connected). If a positional shift occurs during the arrangement of the semiconductor chips, the upper and lower electrodes may not be electrically connected.

The invention aims to provide a resin composition capable of improving the capturing property of a semiconductor chip flying at high speed. The present invention also provides a method for producing a connection structure using the resin composition.

Technical means for solving the technical problems

As a result of intensive studies, the present inventors have found that a semiconductor chip that flies at high speed by a laser transfer method or the like can be captured well by disposing a specific resin composition on the surface of a circuit board (connection target member).

In the present specification, the following resin composition and a method for producing a connection structure using the same are disclosed.

Item 1. A resin composition comprising a thermosetting component, a flux, a thixotropic agent that is liquid at 25 ℃, and solder particles.

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

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

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

The resin composition according to any one of items 2 to 4, wherein the second flux is soluble in the thixotropic agent at 25 ℃.

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.

The resin composition according to any one of items 1 to 6, wherein the thixotropic agent contains glycerin.

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

The resin composition according to any one of items 1 to 8, wherein the solder particles have an average particle diameter of 10 μm or less.

A method for producing a connection structure according to item 10, comprising a first arrangement step of arranging the resin composition on the surface of a first connection object member having at least one first electrode on the surface, a second arrangement step of moving a second connection object member having at least one second electrode on the surface thereof onto the surface of the resin composition opposite to the first connection object member by a laser transfer method, the second connection object member being arranged so that the first electrode and the second electrode face each other, and a connection step of forming a connection portion for connecting the first connection object member and the second connection object member by the resin composition by heating the resin composition to a temperature equal to or higher than the melting point of the solder particles, and electrically connecting the first electrode and the second electrode by the solder portion in the connection portion.

The method of manufacturing a connection structure according to item 10, wherein in the second disposing step, the second connection object member is moved onto a surface of the resin composition opposite to the first connection object member side at a speed of 1cm/s or more by a laser transfer method, and the second connection object member is disposed so that the first electrode and the second electrode face each other.

Effects of the invention

The resin composition of the present invention comprises a thermosetting component, a flux, a thixotropic agent that is liquid at 25 ℃, and solder particles. The resin composition of the present invention has the above-described structure, and therefore, the capturing property of the semiconductor chip that flies at high speed can be improved.

Drawings

Fig. 1 is a cross-sectional view schematically showing a connection structure obtained by using a resin composition according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view illustrating a process of an example of a method for producing a connection structure using the resin composition according to an embodiment of the present invention.

Fig. 3 is a cross-sectional view illustrating a process of an example of a method for producing a connection structure using the resin composition according to an embodiment of the present invention.

Fig. 4 is a cross-sectional view illustrating a process of an example of a method for producing a connection structure using the resin composition according to an embodiment of the present invention.

Fig. 5 is a cross-sectional view showing a modification of the connection structure.

Detailed Description

The present invention will be described in detail below.

(Resin composition)

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

Conventionally, in a method of disposing a semiconductor chip using a laser transfer method, a semiconductor chip may not be disposed accurately at a predetermined position on a circuit board (a member to be connected) due to an impact when the semiconductor chip flies at high speed and lands on the circuit board (the member to be connected). If the positional shift occurs during the arrangement of the semiconductor chips, the upper and lower electrodes may not be electrically connected.

The resin composition of the present invention has the above-described structure, and therefore, the capturing property of the semiconductor chip that flies at high speed can be improved. In particular, the capturing property of the semiconductor chip which flies at high speed by the laser transfer method can be improved. As a result, the flying semiconductor chip can be accurately arranged at a predetermined position on the circuit board (the connection target member) (positional displacement at the time of arranging the semiconductor chip is effectively suppressed).

In the present invention, the use of a specific resin composition contributes significantly to the aforementioned effects.

In the method for producing the connection structure, the resin composition is used by being disposed on the surface of the member to be connected (circuit board, transfer target board). In the method for producing the connection structure, the resin composition is preferably used for capturing a semiconductor chip that flies at a high speed by a laser transfer method. The resin composition is preferably a resin composition for capturing a semiconductor chip by a laser transfer method.

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

The contact angle of the resin composition with water at 25 ℃ is preferably 65 ° or less, more preferably 60 ° or less, further preferably 55 ° or less, particularly preferably 45 ° or less. When the contact angle of the resin composition with respect to water at 25 ℃ is not more than the upper limit, the capturing property of the semiconductor chip which flies at high speed by the laser transfer method can be further improved. Specifically, the electrode of the semiconductor chip generally contains gold, copper, or an alloy thereof, and therefore the surface of the electrode of the semiconductor chip has hydrophilicity in many cases. When the contact angle of the resin composition of the present invention with respect to water is at most the upper limit at 25 ℃, the surface of the resin composition has hydrophilicity, and therefore, the resin composition has high affinity with the surface of the electrode of the semiconductor chip, and when the resin composition is disposed on the surface of the member to be connected (circuit board), the capturing property of the semiconductor chip which flies 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 ℃ is not particularly limited. The contact angle of the resin composition with respect to water at 25 ℃ may be 0 ° or more, may exceed 0 °, may be 1 ° or more, or may be 5 ° or more. The range of the contact angle may be set by appropriately selecting the lower limit value and the upper limit value.

The contact angle of the resin composition with respect to water at 25 ℃ can be measured, for example, by the following method. 1ml of water was dropped onto the surface of the resin composition, and the contact angle of the resin composition with respect to water was measured using a contact angle measuring device. Examples of the contact angle measuring device include "DMo-601" manufactured by KYOWA. The contact angle of the resin composition with water at 25 ℃ is measured after 10 seconds from the time the water is disposed on the surface of the resin composition.

The contact angle of the resin composition with respect to water at 25 ℃ can be adjusted by the following method or the like. A method of combining a plurality of skeletons of a thermosetting component such as an epoxy resin. A method of selecting a skeleton of a thermosetting component such as an epoxy resin. A method of selecting a side chain of a thermosetting component such as an epoxy resin. A method of dispersing an additive in a liquid state at 25 ℃ in a resin composition.

The resin composition is preferably in a liquid state at 25 ℃. The paste is contained in a liquid state. The resin composition is preferably pasty at 25 ℃. The resin composition contains solder particles and is thus a conductive material. The resin composition is preferably a conductive paste. The resin composition is preferably a conductive paste at 25 ℃. In these cases, the resin composition can be applied to the surface of the member to be connected in a thin manner, so that the capturing property of the semiconductor chip which flies at high speed by the laser transfer method can be improved more effectively, and the aggregation property of the solder at the time of conductive connection can be improved more effectively.

The viscosity (. Eta.25) of the resin composition at 25℃is preferably 30 Pa.s or more, more preferably 50 Pa.s or more, preferably 250 Pa.s or less, more preferably 200 Pa.s or less. When the viscosity (η25) is equal to or higher than the lower limit, the capturing property of the semiconductor chip which flies at high speed by the laser transfer method can be more effectively improved. When the viscosity (η25) is equal to or less than the upper limit, the resin composition can be applied to the surface of the member to be connected in a thin and favorable manner, and the cohesiveness of the solder at the time of conductive connection can be effectively improved. The viscosity (. Eta.25) can be appropriately adjusted depending on the kind of the blending component and the blending amount.

The viscosity (. Eta.25) can be measured, for example, using an E-type viscometer (TVE-22L manufactured by Dong machine industries, inc.) at 25℃and 5 rpm.

The viscosity (. Eta.mp) of the resin composition at the melting point of the solder particles is preferably 0.1 Pa.s or more, more preferably 1 Pa.s or more, preferably 10 Pa.s or less, more preferably 5 Pa.s or less. The viscosity (. Eta.mp) can be appropriately adjusted depending on the kind and the blending amount of the blending ingredient. When the viscosity (ηmp) is equal to or higher than the lower limit and equal to or lower than the upper limit, the cohesiveness of the solder at the time of conductive connection can be more effectively improved, voids at the connection portion can be more effectively suppressed, and overflow of the resin composition to the outside of the connection portion can be more effectively suppressed. If the viscosity (. Eta.mp) is not less than the lower limit and not more than 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.

The viscosity (. Eta.mp) can be measured, for example, using a viscoelasticity measuring apparatus (HAAKE, manufactured by SCIENTIFIC Co., ltd.) under conditions of stress control of 1Pa, frequency of 1Hz, heating rate of 20℃per minute, and measurement temperature range of 25℃to 200 ℃. However, when the melting point of the solder particles exceeds 200 ℃, 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.

The resin composition can be used as a conductive paste, a conductive film, and the like. The conductive paste is preferably an anisotropic conductive paste, and the conductive film is preferably an anisotropic conductive film. The resin composition is preferably paste, and is preferably conductive paste, from the viewpoint of more effectively suppressing positional displacement at the time of arrangement of the members to be connected and more effectively improving the cohesiveness of the solder at the time of conductive connection. The resin composition is suitable for electrical connection of electrodes. The resin composition is preferably a circuit connecting material.

The components contained in the resin composition will be described below. In the present specification, the term "(meth) acrylate" means both acrylate and methacrylate. The term "(meth) acrylic" refers to both acrylic and methacrylic. The term "(meth) acryl" means acryl and methacryl.

(Thermosetting component)

The resin composition of the present invention comprises a thermosetting component. The thermosetting component preferably comprises a thermosetting compound. The resin composition may or may not contain a thermosetting agent as a thermosetting component. In the resin composition of the present invention, with the above-described configuration, even when the resin composition does not contain a thermosetting agent, the capturing property of the semiconductor chip that flies at high speed by the laser transfer method can be improved. The resin composition preferably does not contain a thermosetting agent from the viewpoint of more effectively improving the cohesiveness of the solder at the time of conductive connection. In order to cure the resin composition more well, the resin composition may contain a curing accelerator as a thermosetting component.

(Thermosetting component: thermosetting Compound)

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, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, polysiloxane compounds, and polyimide compounds. The thermosetting compound is preferably an epoxy compound or an episulfide compound, and more preferably an epoxy compound, from the viewpoint of improving the curability and viscosity of the resin composition and further improving the conduction reliability. The resin composition preferably contains an epoxy compound or an episulfide compound, more preferably contains an epoxy compound. The thermosetting compound may be used alone or in combination of two or more.

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

The epoxy compound is liquid or solid at normal temperature (25 ℃), and in the case where the epoxy compound is solid at normal temperature, the melting temperature of the epoxy compound is preferably not higher than the melting point of the solder particles. By using the above-mentioned preferable epoxy compound, the viscosity is high at the stage of bonding the members to be connected, and when acceleration is applied by an impact such as a transfer, positional displacement between the members to be connected (circuit board) and the semiconductor chip can be suppressed. Further, the viscosity of the resin composition can be greatly reduced by heat during curing, and the solder can be efficiently aggregated during conductive connection.

From the viewpoint of more effectively improving the insulation reliability and more effectively improving the conduction reliability, the thermosetting component preferably contains an epoxy compound, and the thermosetting compound preferably contains an epoxy compound.

The thermosetting compound preferably contains a thermosetting compound having a polyether skeleton from the viewpoint of more effectively disposing a solder on an electrode.

Examples of the thermosetting compound having a polyether skeleton include a compound having glycidyl ether groups at both ends of an alkyl chain having 3 to 12 carbon atoms, and a polyether epoxy compound having a polyether skeleton having 2 to 4 carbon atoms and having 2 to 10 structural units obtained by continuously bonding the polyether skeleton.

The thermosetting compound preferably contains a thermosetting compound having an isocyanuric acid skeleton from the viewpoint of more effectively improving the heat resistance of the cured product.

Examples of the thermosetting compound having an isocyanuric acid skeleton include triisocyanurate type epoxy compounds and the like, and examples thereof include TEPIC series (TEPIC-G, TEPIC-S, TEPIC-SS, TEPIC-HP, TEPIC-L, TEPIC-PAS, TEPIC-VL and TEPIC-UC) manufactured by Nissan chemical industry Co.

The thermosetting compound preferably has high heat resistance, and more preferably contains a novolac-type epoxy compound, from the viewpoint of more efficiently disposing solder on the electrodes, from the viewpoint of more effectively improving the conduction reliability between the upper and lower electrodes to be connected, and from the viewpoint of more effectively suppressing discoloration of the thermosetting compound. The novolac epoxy compound has high heat resistance.

In the resin composition, the content of the thermosetting compound is preferably 5 wt% or more, more preferably 8 wt% or more, further preferably 10 wt% or more, preferably 99 wt% or less, more preferably 90 wt% or less, further preferably 80 wt% or less, and particularly preferably 70 wt% or less, based on 100 wt% of the resin composition. When the content of the thermosetting compound is not less than the lower limit and not more than the upper limit, the capturing property of the semiconductor chip which flies at high speed by the laser transfer method can be more effectively improved, the solder can be more effectively arranged 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 more effectively improving the impact resistance of the resulting connection structure, it is preferable that the content of the thermosetting compound is large.

In the resin composition, the content of the epoxy compound is preferably 5wt% or more, more preferably 8 wt% or more, further preferably 10 wt% or more, preferably 99 wt% or less, more preferably 90 wt% or less, further preferably 80 wt% or less, and particularly preferably 70 wt% or less, based on 100 wt% of the resin composition. When the content of the epoxy compound is not less than the lower limit and not more than the upper limit, the capturing property of the semiconductor chip which flies at high speed by the laser transfer method can be more effectively improved, the solder can be more effectively arranged 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. The content of the epoxy compound is preferably large from the viewpoint of further improving the impact resistance of the resulting connection structure.

The content of the novolak type epoxy compound in the resin composition is preferably 1 wt% or more, more preferably 3wt% or more, further preferably 5 wt% or more, preferably 99 wt% or less, more preferably 90 wt% or less, further preferably 80 wt% or less, and particularly preferably 70 wt% or less, based on 100 wt% of the resin composition. When the content of the novolac type epoxy compound is not less than the lower limit and not more than the upper limit, the capturing property of the semiconductor chip which flies at high speed by the laser transfer method can be more effectively improved, the solder can be more effectively arranged 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 resulting connection structure, the content of the novolac-type epoxy compound is preferably large.

(Soldering flux)

The resin composition includes a flux. By using the flux, the cohesiveness of the solder at the time of conductive connection can be more effectively improved.

Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic acid amine salt, an organic halide, hydrazine, an amine compound different from the organic acid amine salt, and rosin. The flux may be used alone or in combination of two or more.

The soldering flux preferably comprises an organic acid or an amine salt of an organic acid. The organic acid is preferably a dicarboxylic acid and the organic acid amine salt is preferably a dicarboxylic acid amine salt. The fluxing agent preferably comprises a dicarboxylic acid or an amine salt of a dicarboxylic acid, more preferably comprises a dicarboxylic acid and an amine salt of a dicarboxylic acid.

Examples of the dicarboxylic acid include glutaric acid, adipic acid, azelaic acid, pimelic acid, and the like.

Examples of the dicarboxylic acid amine salt include benzyl glutarate, benzyl adipate, benzyl azelate, stearyl glutarate, stearyl adipate, and stearyl azelate.

The flux is preferably solid. The flux may be spherical, may be other than spherical, or may be flat.

From the viewpoint of more effectively improving the capturing property of a semiconductor chip which flies at high speed by a laser transfer method, the flux preferably contains two or more fluxes having main chains with different carbon numbers. From the viewpoint of more effectively improving the capturing property of a semiconductor chip which flies at high speed by a laser transfer method, the flux preferably contains 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 used alone or two or more kinds of fluxes may be used. The second flux may be used alone or two or more kinds of fluxes may be used.

The number of carbon atoms of the main chain of the first soldering flux is an even number. The number of carbon atoms of the main chain of the first flux is an even number, and the number of carbon atoms of 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 of the main chain of the first flux is preferably an even number of 4 to 14. When the number of carbon atoms in the main chain of the first flux is not less than the lower limit and not more than the upper limit, the solder can be more efficiently disposed on the electrode.

The number of carbon atoms of the main chain of the second soldering flux is odd. The number of carbon atoms of the main chain of the second flux is an odd number, and the number of carbon atoms of the main chain of the second flux is preferably 3 or more, preferably 11 or less, more preferably 9 or less, and further preferably 7 or less. The number of carbon atoms of the main chain of the second flux is preferably an odd number of 3 to 11. When the number of carbon atoms in the main chain of the second flux is not less than the lower limit and not more than the upper limit, the solder can be more efficiently disposed on the electrode.

The average particle diameter of the flux (average particle diameter of the flux as a whole) 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. When the average particle diameter of the flux is not more than the upper limit, the capturing property of the semiconductor chip which flies at high speed by the laser transfer method can be more effectively improved. The lower limit of the average particle diameter of the flux is not particularly limited. The flux may have an average particle diameter of 0.01 μm or more, or 0.1 μm or more, or 0.5 μm or more, or 1.0 μm or more. The range of the average particle diameter of the flux may be set by appropriately selecting the lower limit value and the upper limit value.

The average particle diameter of the first flux is preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less. When the average particle diameter of the first flux is equal to or smaller than the upper limit, the capturing property of the semiconductor chip which flies at high speed by the laser transfer method can be more effectively improved. The lower limit of the average particle diameter of the first flux is not particularly limited. The average particle diameter of the first flux may be 0.5 μm or more, or may be 1.0 μm or more. The range of the average particle diameter of the first flux may be set by appropriately selecting the lower limit value and the upper limit value.

The average particle diameter of the second flux is preferably 7 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less. When the average particle diameter of the second flux is equal to or smaller than the upper limit, the capturing property of the semiconductor chip which flies at high speed by the laser transfer method can be more effectively improved. The lower limit of the average particle diameter of the second flux is not particularly limited. The second flux may have an average particle diameter of 0.01 μm or more or 0.1 μm or more. The range of the average particle diameter of the second flux may be set by appropriately selecting the lower limit value and the upper limit value.

The average particle size of the soldering flux and the average particle sizes of the first and second soldering fluxes are number average particle sizes. The average particle size of the flux and the average particle sizes of the first and second fluxes are obtained by observing any 50 fluxes with an electron microscope or an optical microscope, for example, and calculating the average particle size of each flux, or by measuring the laser diffraction type particle size distribution. In observation under an electron microscope or an optical microscope, the particle diameter of each flux was obtained as the particle diameter at the equivalent circle diameter. In observation under an electron microscope or an optical microscope, the average particle diameter at the equivalent circle diameter of any 50 fluxes is substantially equal to the average particle diameter at the equivalent sphere diameter. In the laser diffraction type particle size distribution measurement, the particle size of each flux was obtained as the particle size at the equivalent spherical diameter. The average particle size of the flux and the average particle sizes of the first and second fluxes are preferably calculated by measuring a laser diffraction type particle size distribution.

The flux and the first and second fluxes may be pulverized products of commercially available fluxes. As a method of pulverizing a flux which is commercially available, an agate mortar pulverizing method, a jet mill pulverizing method, a bead mill pulverizing method, and the like can be mentioned.

The coefficient of variation (CV value) of the particle diameter of the flux (coefficient of variation (CV value) of the particle diameter of the flux as a whole) is preferably 10% or less, more preferably 5% or less. When the coefficient of variation in the particle diameter of the flux is equal to or less than the upper limit, the flux can be more efficiently disposed on the electrode. The lower limit of the coefficient of variation (CV value) of the particle diameter of the flux is not particularly limited. The coefficient of variation (CV value) of the particle diameter of the flux may be 0% or more, or may be 1% or more, or may be 5% or more. The range of the coefficient of variation of the particle diameter of the flux may be set by appropriately selecting the lower limit value and the upper limit value.

The coefficient of variation (CV value) of the particle diameter of the flux can be measured as follows.

CV value (%) = (ρ/Dn) ×100

Standard deviation of particle size of flux

Dn mean particle size of flux

The active temperature (melting point) of the flux is preferably 50 ℃ or higher, more preferably 70 ℃ or higher, further preferably 80 ℃ or higher, preferably 200 ℃ or lower, more preferably 190 ℃ or lower, further preferably 180 ℃ or lower. When the activation temperature of the flux is not lower than the lower limit and not higher than the upper limit, the flux effect is more effectively exerted, and the solder is more effectively arranged on the electrode. The active temperature (melting point) of the flux is preferably 70 ℃ to 190 ℃, particularly preferably 80 ℃ to 180 ℃.

The active temperature (melting point) of the flux can be determined by differential scanning calorimetric measurement (DSC). Examples of the Differential Scanning Calorimetric (DSC) apparatus include "EXSTAR DSC7020" manufactured by SII Co.

Examples of the flux having an activation temperature (melting point) of 80 ℃ to 180 ℃ inclusive include dicarboxylic acids such as glutaric acid (melting point 96 ℃), benzyl glutarate (melting point 108 ℃) and adipic acid (melting point 152 ℃) and benzyl adipate (melting point 180 ℃) and pimelic acid (melting point 104 ℃) and suberic acid (melting point 142 ℃) and malic acid (melting point 130 ℃) respectively.

The boiling point of the flux is preferably 200 ℃ or less.

From the viewpoint of improving the coatability and screen printability of the resin composition, the second flux is preferably soluble in the thixotropic agent at 25 ℃. The first flux may or may not be soluble in the thixotropic agent at 25 ℃. From the standpoint of improving the coatability and screen printability of the resin composition and improving the cohesiveness of the solder particles, the first flux is preferably insoluble in the thixotropic agent at 25 ℃, and the second flux is soluble in the thixotropic agent at 25 ℃. In the present specification, the term "flux is soluble in the thixotropic agent" means that 10g of flux is put into 20g of the thixotropic agent, and when the flux is held at 25 ℃ for 10 minutes, the weight of flux dissolved in the thixotropic agent is 4g or more.

The flux and the first and second fluxes may be dispersed in a resin composition or may be attached to the surfaces of solder particles. The second flux may be used dissolved in a thixotropic agent. The material of the resin composition may contain a second flux dissolved in a thixotropic agent.

The first flux is preferably 1, 10-decanedicarboxylic acid, adipic acid or a salt thereof, more preferably adipic acid or a salt of adipic acid, from the viewpoint of more efficient arrangement of solder on the electrode. The first flux is preferably 1, 10-decanedicarboxylic acid or adipic acid, more preferably adipic acid, from the viewpoint of more efficient arrangement of solder on the electrode.

The second flux is preferably pimelic acid, azelaic acid, glutaric acid or salts thereof, more preferably azelaic acid, salts of azelaic acid, glutaric acid or salts of glutaric acid, from the viewpoint of more efficient arrangement of the solder on the electrode. The second flux is preferably pimelic acid, glutaric acid or a salt thereof, more preferably glutaric acid or a salt of glutaric acid, from the viewpoint of more efficient arrangement of the solder on the electrode. The second flux is preferably pimelic acid or glutaric acid, more preferably glutaric acid, from the viewpoint of more efficient arrangement of the solder on the electrode.

The flux is preferably a flux that releases cations by heating. The first flux is preferably a flux that releases cations by heating. The second flux is preferably a flux that releases cations by heating. By using a flux that releases cations by heating, solder can be more effectively disposed on the electrode.

In the resin composition 100 wt%, the content of the flux (the content of the entire flux) is preferably 5 wt% or more, more preferably 10 wt% or more, further preferably 15 wt% or more, preferably 30 wt% or less, and further preferably 25 wt% or less. When the content of the flux is not less than the lower limit and not more than the upper limit, an oxide film is less likely to be formed on the surfaces of the solder and the electrode, and the oxide film formed on the surfaces of the solder and the electrode can be removed more effectively. In the case where the flux contains the first flux and the second flux, the content of the flux indicates the sum of the content of the first flux and the content of the second flux (hereinafter, the same applies).

In the resin composition, the content of the first flux is preferably 5wt% or more, more preferably 8 wt% or more, further preferably 10 wt% or more, preferably 25 wt% or less, more preferably 20 wt% or less, further preferably 15 wt% or less, based on 100 wt% of the resin composition. When the content of the first flux is not less than the lower limit and not more than the upper limit, the solder aggregation property can be improved.

In the resin composition, the content of the second flux is preferably 1wt% or more, more preferably 2wt% or more, further preferably 5wt% or more, preferably 25 wt% or less, more preferably 20 wt% or less, further preferably 15 wt% or less, based on 100 wt% of the resin composition. When the content of the second flux is not less than the lower limit and not more than the upper limit, the coatability and screen printability of the resin composition can be improved.

In the flux 100 wt%, the content of the first flux is preferably 40 wt% or more, more preferably 50 wt% or more, further preferably 60 wt% or more, preferably 100 wt% or less, more preferably less than 100 wt%, further preferably 90 wt% or less, particularly preferably 80 wt% or less, and most preferably 70 wt% or less. When the content of the first flux is not less than the lower limit and not more than the upper limit, the coatability and screen printability of the resin composition can be improved.

The content of the flux (the content of the entire flux) is preferably 100 parts by weight or more, more preferably 150 parts by weight or more, further preferably 200 parts by weight or more, preferably 500 parts by weight or less, more preferably 400 parts by weight or less, further preferably 300 parts by weight or less, relative to 100 parts by weight of the thixotropic agent. When the content of the flux is not less than the lower limit and not more than the upper limit, the coatability and screen printability of the resin composition can be improved.

The content of the first flux is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, still more preferably 40 parts by weight or more, still more preferably 100 parts by weight or more, particularly preferably 150 parts by weight or more, most preferably 200 parts by weight or more, preferably 500 parts by weight or less, still more preferably 400 parts by weight or less, and still more preferably 300 parts by weight or less, based on 100 parts by weight of the thixotropic agent. When the content of the first flux is not less than the lower limit and not more than the upper limit, the coatability and screen printability of the resin composition can be improved.

The content of the second flux is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, further preferably 40 parts by weight or more, preferably 100 parts by weight or less, more preferably 80 parts by weight or less, further preferably 60 parts by weight or less, based on 100 parts by weight of the thixotropic agent. When the content of the second flux is not less than the lower limit and not more than the upper limit, the coatability and screen printability of the resin composition can be improved.

(Thixotropic agent)

The resin composition comprises a thixotropic agent that is liquid at 25 ℃.

Examples of the thixotropic agent include ethylene glycol, diethylene glycol, 2-phenylethanol, 1, 3-propanediol, glycerol, and the like. The thixotropic agent may be used alone or in combination of two or more.

From the viewpoint of improving coatability and screen printability, the thixotropic agent preferably contains a compound having polarity, more preferably contains a compound having a hydroxyl group or a carboxyl group. From the viewpoint of improving coatability and screen printability, the thixotropic agent preferably contains ethylene glycol, diethylene glycol, 2-phenylethanol, 1, 3-propanediol or glycerin, more preferably contains ethylene glycol, 1, 3-propanediol or glycerin. The thixotropic agent particularly preferably contains glycerin from the viewpoint of improving coatability and screen printability.

From the viewpoint of improving the coatability and screen printability 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 glycerin or 1, 3-propanediol. 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 glycerin or 1, 3-propanediol, from the viewpoint of improving the coatability and screen printability of the resin composition. From the viewpoint of improving the coatability and screen printability of the resin composition, it is preferable that the second flux contains glutaric acid or a salt of glutaric acid, and the thixotropic agent contains glycerin. From the viewpoint of improving the coatability and screen printability of the resin composition, it is preferable that the second flux is glutaric acid or a salt of glutaric acid, and the thixotropic agent is glycerin. From the viewpoint of improving the coatability and screen printability of the resin composition, it is preferable that the second flux is glutaric acid and the thixotropic agent is glycerin.

From the viewpoint of improving the coatability and screen printability of the resin composition, the resin composition particularly preferably contains azelaic acid, a salt of azelaic acid, glutaric acid or a salt of glutaric acid and glycerin or 1, 3-propanediol in a state where azelaic acid, a salt of azelaic acid, glutaric acid or a salt of glutaric acid is dissolved in glycerin or 1, 3-propanediol. From the viewpoint of improving the coatability and screen printability of the resin composition, the resin composition particularly preferably contains glutaric acid or a salt of glutaric acid and glycerin in a state where glutaric acid or a salt of glutaric acid is dissolved in glycerin. From the viewpoint of improving the coatability and screen printability of the resin composition, the resin composition particularly preferably contains glutaric acid and glycerin in a state where glutaric acid is dissolved in glycerin.

The hydrogen bond term δh in hansen solubility parameters of the thixotropic agent is preferably 10MPa ^1/2 or more, more preferably 12MPa ^1/2 or more, further preferably 14MPa ^1/2 or more, and particularly preferably 16MPa ^1/2 or more. When the hydrogen bond term δh in the hansen solubility parameter of the thixotropic agent is not less than the lower limit, the coatability and screen printability of the resin composition can be improved. The upper limit of the hydrogen bond term δh in the hansen solubility parameter of the thixotropic agent is not particularly limited. The hydrogen bond term delta H in the hansen solubility parameter of the thixotropic agent can be below 100MPa ^1/2 or below 50MPa ^1/2.

The hydrogen bond term δh in the hansen solubility parameter of the thixotropic agent can be easily deduced, for example, by using computer software "Hansen Solubility PARAMETERS IN PRACTICE (hsPIP)".

In the resin composition, the thixotropic agent is preferably contained in an amount of 1 wt% or more, more preferably 2 wt% or more, still more preferably 3 wt% or more, preferably 20wt% or less, more preferably 15 wt% or less, still more preferably 10wt% or less, based on 100 wt% of the resin composition. When the thixotropic agent content is not less than the lower limit and not more than the upper limit, the coatability and screen printability of the resin composition can be improved.

In the resin composition, the content of glycerin 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, based on 100% by weight of the resin composition. When the content of glycerin is not less than the lower limit and not more than the upper limit, the coatability and screen printability of the resin composition can be improved.

(Solder particles)

The resin composition includes solder particles. The center portion and the outer surface of the solder particles are each formed of solder. The solder particles are particles each having a center portion and an outer surface of which are solder. In the case of using conductive particles having base particles made of a material other than solder and solder portions arranged on the surface of the base particles instead of the solder particles, the conductive particles are hard to be accumulated on the electrodes. In addition, among the conductive particles, since the solder-bondability of the conductive particles to each other is low, the conductive particles that move to the electrode tend to easily move to the outside of the electrode.

The solder is preferably a metal (low-melting metal) having a melting point of 450 ℃ or less. The solder particles are preferably metal particles (low-melting metal particles) having a melting point of 450 ℃ or less. The low-melting metal particles are particles containing a low-melting metal. The low-melting point metal means a metal having a melting point of 450 ℃ or less. The melting point of the low-melting metal is preferably 300 ℃ or less, more preferably 220 ℃ or less, and further preferably 190 ℃ or less.

The melting point of the solder particles is preferably 100 ℃ or more, more preferably 105 ℃ or more, preferably 250 ℃ or less, more preferably 245 ℃ or less. When the melting point of the solder particles is not less than the lower limit and not more than the upper limit, the cohesiveness of the solder at the time of conductive connection can be more effectively improved. When the melting point of the solder particles is equal to or higher than the lower limit and equal to or lower than the upper limit, the conduction reliability can be more effectively improved and the insulation reliability can be more effectively improved when the electrodes are electrically connected.

The melting point of the solder particles can be determined by Differential Scanning Calorimetry (DSC). Examples of the Differential Scanning Calorimetric (DSC) apparatus include "EXSTAR DSC7020" manufactured by SII Co.

The solder particles preferably contain 90% by weight or more of solder in 100% by weight of the solder particles. In addition, the solder particles preferably contain tin. The content of tin in 100 wt% of the metal contained in the solder particles is preferably 30 wt% or more, more preferably 40 wt% or more, further preferably 70 wt% or more, and particularly preferably 90 wt% or more. If the content of tin in the solder particles is not less than the lower limit, the connection reliability between the solder portion and the electrode can be more effectively improved.

The tin content may be measured using a high-frequency inductively coupled plasma emission spectrometry device (ICP-AES, manufactured by horiba corporation) or a fluorescent X-ray analysis device (EDX-800 HS, manufactured by shimadzu corporation).

By using the solder particles, the solder is melted and bonded to the electrodes, and the solder portion conducts between the electrodes. For example, the solder portion is not in point contact with the electrode but easily in surface contact, and thus the connection resistance becomes low. In addition, by using the solder particles, the bonding strength between the solder portion and the electrode is increased, and as a result, the peeling between the solder portion and the electrode is less likely to occur, and the conduction reliability and the connection reliability can be more effectively improved.

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 the alloy include tin-silver alloy, tin-copper alloy, tin-silver-copper alloy, tin-bismuth alloy, tin-zinc alloy, and tin-indium alloy. The low-melting point metal is preferably tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, or a tin-indium alloy because of excellent wettability to the electrode. The low melting point metal is more preferably a tin-bismuth alloy or a tin-indium alloy.

The solder particles are preferably filler metals having a liquidus of 450 ℃ or less based on JIS Z3001, a welding term. Examples of the composition of the solder particles include a metal composition containing zinc, gold, silver, lead, copper, tin, bismuth, indium, and the like. The solder particles are preferably lead-free, preferably comprising tin and indium, or comprising tin and bismuth.

In order to further effectively improve the bonding strength between the solder portion and the electrode, the solder particles may also contain 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 of the solder portion and the electrode, the solder particles preferably contain nickel, copper, antimony, aluminum or zinc. The content of these metals for improving the bonding strength is preferably 0.0001 wt% or more, and more preferably 1 wt% or less, of 100 wt% of the metals contained in the solder particles, from the viewpoint of more effectively improving the bonding strength between the solder portion and the electrode.

The average particle diameter of the solder particles is preferably 0.01 μm or more, more preferably 0.03 μm or more. When the average particle diameter of the solder particles is not less than the lower limit, the solder can be more efficiently arranged on the electrode. The average particle diameter of the solder particles may be 10 μm or less, may be 5 μm or less, or may be 3 μm or less. The range of the average particle diameter of the solder particles may be set by appropriately selecting the lower limit value and the upper limit value.

The average particle diameter of the solder particles is a number average particle diameter. The average particle diameter of the solder particles is obtained by, for example, observing arbitrary 50 solder particles with an electron microscope or an optical microscope, calculating an average value of particle diameters of the solder particles, or measuring a laser diffraction type particle size distribution. In observation with an electron microscope or an optical microscope, the particle diameter of each solder particle was obtained as the particle diameter at the equivalent circle diameter. In observation with an electron microscope or an optical microscope, the average particle diameter at the equivalent circle diameter of any 50 solder particles is substantially equal to the average particle diameter at the equivalent sphere diameter. In the laser diffraction particle size distribution measurement, the particle diameter of each solder particle was obtained as the particle diameter at the equivalent spherical diameter. The average particle diameter of the solder particles is preferably calculated by measurement of a laser diffraction type particle size distribution.

The coefficient of variation (CV value) of the particle diameter of the solder particles is preferably 5% or more, more preferably 10% or more, preferably 40% or less, more preferably 30% or less. When the coefficient of variation of the particle diameter of the solder particles is not less than the lower limit and not more than the upper limit, the solder can be more efficiently arranged on the electrode. However, the CV value of the particle diameter of the solder particles may be less than 5%.

The coefficient of variation (CV value) can be determined as follows.

CV value (%) = (ρ/Dn) ×100

Standard deviation of particle diameter of solder particles

Dn average particle diameter of solder particles

The shape of the solder particles is not particularly limited. The solder particles may have a spherical shape, a shape other than a spherical shape, or a flat shape.

In the resin composition, the content of the solder particles is preferably 1 wt% or more, more preferably 2 wt% or more, further preferably 10 wt% or more, particularly preferably 20 wt% or more, most preferably 30 wt% or more, preferably 80 wt% or less, further preferably 60 wt% or less, further preferably 50 wt% or less, based on 100 wt% of the resin composition. When the content of the solder particles is not less than the lower limit and not more than the upper limit, the solder can be more efficiently arranged on the electrodes, and a large amount of solder can be easily arranged between the electrodes, thereby more effectively improving the conduction reliability. From the viewpoint of more effectively improving the conduction reliability, the content of the solder particles is preferably large.

(Other Components)

The resin composition may contain various additives such as a filler, an extender, a softener, a plasticizer, a thickener, a leveling agent, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent, and a flame retardant, as required.

(Connection Structure and method for manufacturing connection Structure)

The connection structure of the present invention comprises a first connection object member having a first electrode on the surface, a second connection object member having a second electrode on the surface, and a connection portion for connecting the first connection object member and the second connection object member. 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 electrode and the second electrode are electrically connected by the solder portion in the connection portion.

In the connection structure of the present invention, since a specific resin composition is used, solder is easily accumulated between the first electrode and the second electrode, and the solder can be efficiently arranged on the electrode (wire). In addition, a part of the solder is not easily disposed in the region (space) where the electrode is not formed, and the amount of solder disposed in the region where the electrode is not formed can be made considerably small. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. Further, electrical connection between the electrodes adjacent in the lateral direction, which cannot be connected, can be prevented, and insulation reliability can be improved.

In order to efficiently dispose the solder on the electrode and to considerably reduce the amount of the solder disposed in the region where the electrode is not formed, the resin composition preferably uses a conductive paste rather than a conductive film.

In the connection structure, it is preferable that the first connection target member is a circuit board. In the connection structure, the second connection object member is preferably a semiconductor chip.

The method for manufacturing a connection structure according to the present invention includes the following steps. (1) And a first disposing step of disposing the resin composition on a surface of a first member to be connected having at least one first electrode on a surface thereof, using the resin composition. (2) And a second disposing step of moving a second member to be connected having at least one second electrode on a surface thereof onto a surface of the resin composition opposite to the first member to be connected by a laser transfer method, wherein the second member to be connected is disposed such that the first electrode faces the second electrode. (3) And a connection step of forming a connection portion for connecting the first connection target member and the second connection target member by the resin composition by heating the resin composition to a temperature equal to or higher than the melting point of the solder particles, and electrically connecting the first electrode and the second electrode by the solder portion in the connection portion.

In the method for manufacturing a connection structure according to the present invention, since the structure is provided, the capturing property of the second connection object member (semiconductor chip) that flies at high speed by the laser transfer method can be improved.

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

Fig. 1 is a cross-sectional view schematically showing a connection structure obtained by using a resin composition according to an embodiment of the present invention.

The connection structure 1 shown in fig. 1 includes a first member 2 to be connected, a second member 3 to be connected, and a connection portion 4 for connecting the first member 2 to be connected and the second member 3 to be connected. The connection portion 4 is formed of the resin composition.

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

The connection portion 4 includes a solder portion 4A in which a plurality of solder particles are aggregated and bonded to each other, and a cured portion 4B in which a thermosetting component is thermally cured.

The first connection object member 2 has a plurality of first electrodes 2a on a surface (upper surface). The second connection object member 3 has a plurality of second electrodes 3a on a surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A. Therefore, the first connection object member 2 and the second connection object member 3 are electrically connected by the solder portion 4A. In the connection portion 4, no solder is present in a region (solidified portion 4B) different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a. In a region (cured portion 4B portion) different from the solder portion 4A, there is no solder separated from the solder portion 4A. If the amount is small, solder may be present in a region (solidified portion 4B) different from the solder portion 4A collected between the first electrode 2a and the second electrode 3a.

As shown in fig. 1, in the connection structure 1, a plurality of solder particles are collected between the first electrode 2a and the second electrode 3a, and after the plurality of solder particles are melted, the melted solder particles are infiltrated and spread on the surface of the electrode, and then solidified, thereby forming the solder portion 4A. Therefore, the connection area between the solder portion 4A and the first electrode 2a and the connection area between the solder portion 4A and the second electrode 3a become large. That is, by using the solder particles, the contact area between the solder portion 4A and the first electrode 2a and the contact area between the solder portion 4A and the second electrode 3a become larger than in the case of using conductive particles in which the outer surface portion of the conductive portion is made of a metal such as nickel, gold, or copper. Therefore, the connection reliability in the connection structure 1 is improved. The flux and the thixotropic agent contained in the resin composition are usually gradually deactivated by heating.

In the connection structure 1 shown in fig. 1, the solder portions 4A are all located in the region opposed to each other between the first and second electrodes 2a, 3 a. The connection structure 1X of the modification shown in fig. 5 differs from the connection structure 1 shown in fig. 1 only in the connection portion 4X. The connection portion 4X has a solder portion 4XA and a cured portion 4XB. As in the connection structure 1X, most of the solder portion 4XA may be located in the opposing region of the first and second electrodes 2a and 3a, and part of the solder portion 4XA may protrude laterally from the opposing region of the first and second electrodes 2a and 3 a. The solder portion 4XA extending laterally from the opposing regions of the first and second electrodes 2a, 3a is a part of the solder portion 4XA, and is not solder separated from the solder portion 4 XA. In the present embodiment, the amount of solder away from the solder portion can be reduced, but the solder away from the solder portion may be present in the solidified portion.

If the amount of solder particles used is reduced, the connection structure 1 can be easily obtained. If the amount of solder particles used is increased, the connection structure 1X is easily obtained.

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, more preferably 80 μm or less. In the first electrode and the second electrode, a solder wetting area (an area of solder contact in 100% of an exposed area of the electrode) on a surface 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 connection portion satisfy the preferable manner, the conduction reliability and the insulation reliability can be more effectively improved.

In the connection structures 1 and 1X, it is preferable that, when the portions of the first electrode 2a and the second electrode 3a facing each other are viewed in the lamination direction of the first electrode 2a and the connection portions 4 and 4X and the second electrode 3a, the solder portions 4A and 4XA in the connection portions 4 and 4X are disposed at 50% or more of 100% of the area of the portions of the first electrode 2a and the second electrode 3a facing each other. By satisfying the above-described preferable aspect with respect to the solder portions 4A, 4XA in the connection portions 4, 4X, the conduction reliability can be further improved.

When the portions of the first electrode and the second electrode facing each other are viewed in the lamination direction of the first electrode, the connection portion, and the second electrode, the solder portion in the connection portion is preferably disposed in at least 50% of 100% of the area of the portions of the first electrode and the second electrode facing each other. When the portions of the first electrode and the second electrode that face each other are viewed in the lamination direction of the first electrode, the connection portion, and the second electrode, it is more preferable that the solder portion in the connection portion is disposed in at least 60% of 100% of the area of the portions of the first electrode and the second electrode that face each other. When the portions of the first electrode and the second electrode that face each other are viewed in the lamination direction of the first electrode, the connection portion, and the second electrode, it is further preferable that the solder portion in the connection portion is disposed in at least 70% of 100% of the area of the portions of the first electrode and the second electrode that face each other. When the portions of the first electrode and the second electrode facing each other are viewed in the lamination direction of the first electrode, the connection portion, and the second electrode, it is particularly preferable that the solder portion in the connection portion is disposed in 80% or more of 100% of the area of the portion of the first electrode and the second electrode facing each other. When the portions of the first electrode and the second electrode that face each other are viewed in the lamination direction of the first electrode, the connection portion, and the second electrode, it is most preferable that the solder portion in the connection portion is disposed in 90% or more of 100% of the area of the portion of the first electrode and the second electrode that face each other. By making the solder portion in the connection portion satisfy the preferable mode, the conduction reliability can be further improved.

When the mutually opposing portions of the first electrode and the second electrode are viewed in a direction orthogonal to the lamination direction of the first electrode, the connection portion, and the second electrode, it is preferable that 60% or more of the solder portion in the connection portion is disposed at 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 orthogonal to the lamination direction of the first electrode, the connection portion, and the second electrode, more preferably, 70% or more of the solder portion in the connection portion is disposed at the mutually opposing portions of the first electrode and the second electrode. When the portion of the first electrode and the second electrode facing each other is viewed in a direction orthogonal to the lamination direction of the first electrode, the connection portion, and the second electrode, it is more preferable that 90% or more of the solder portion in the connection portion is disposed at the portion of the first electrode and the second electrode facing each other. When the portion of the first electrode and the second electrode facing each other is viewed in a direction orthogonal to the lamination direction of the first electrode, the connection portion, and the second electrode, it is particularly preferable that 95% or more of the solder portion in the connection portion is disposed at the portion of the first electrode and the second electrode facing each other. When the mutually opposed portions of the first electrode and the second electrode are viewed in a direction orthogonal to the lamination direction of the first electrode, the connection portion, and the second electrode, it is most preferable that 99% or more of the solder portion in the connection portion is disposed at the mutually opposed portions of the first electrode and the second electrode. By making the solder portion in the connection portion satisfy the preferable mode, the conduction reliability can be further improved.

Next, an example of a method for producing the connection structure 1 using the resin composition according to an embodiment of the present invention will be described with reference to fig. 2 to 4. Fig. 2 to 4 are cross-sectional views for explaining steps of an example of a method for producing a connection structure using the resin composition according to an embodiment of the present invention.

First, a first connection target member (circuit substrate) 2 having a first electrode 2a on a surface (upper surface) is prepared. Next, as shown in fig. 2, a resin composition 11 including a thermosetting component 11B, solder particles 11A, a flux 11C, and a thixotropic agent (not shown) that is liquid at 25 ℃ is disposed on the surface of the first member to be connected (circuit board) 2 (first disposing step). The thermosetting component 11B contains a thermosetting compound.

The resin composition 11 is disposed on the surface of the first connection object member (circuit substrate) 2 on which the first electrode 2a is provided. After the arrangement of the resin composition 11, the solder particles 11A, the flux 11C, and the thixotropic agent are arranged on both the first electrode 2a (line) and the region (space) where the first electrode 2a is not formed. The resin composition may be disposed only on the surface of the first electrode.

The method of disposing the resin composition 11 is not particularly limited. Examples of the method for disposing the resin composition 11 include application by a dispenser, screen printing, and ejection by an inkjet device.

In addition, a second connection object member (semiconductor chip) 3 having a second electrode 3a on a surface (lower surface) is prepared. The second connection target member (semiconductor chip) 3 having the second electrode 3a on the surface (lower surface) is arranged on the surface of the transfer source substrate on the support film 6 side provided with the support member 5 and the support film 6. A second connection object member (semiconductor chip) 3 having a second electrode 3a on a surface (lower surface) is arranged on the surface of the support film 6.

Next, as shown in fig. 3, in the resin composition 11 on the surface of the first member to be connected (circuit board) 2, the second member to be connected (semiconductor chip) 3 is moved onto the surface of the resin composition 11 on the opposite side of the first member to be connected (circuit board) 2 by the laser transfer method, and the second member to be connected (semiconductor chip) 3 is arranged (second arranging step). A second member to be connected (semiconductor chip) 3 is disposed on the surface of the resin composition 11 from the second electrode 3a side. In the second disposing step, the laser irradiation device 51 irradiates the laser beam from the support member 5 side of the transfer source substrate, so that the curing reaction of the curable component (resin component) in the support film 6 proceeds, and the adhesion force on the surface of the support film 6 is greatly reduced. As a result, the second member to be connected (semiconductor chip) 3 is peeled off from the transfer source substrate (particularly, the support film 6) and moved onto the surface of the resin composition 11 on the side opposite to the first member to be connected (circuit substrate) 2 side. The second connection target member (semiconductor chip) 3 moves alone with the second connection target member (semiconductor chip) 3, for example, in a state where the surface of the second connection target member (semiconductor chip) 3 is not in contact with other members (a state where the surface is not held by other members). At this time, the first electrode 2a is opposed to the second electrode 3 a.

In the present embodiment, since the resin composition is used, the capturing property of the second member to be connected (semiconductor chip) 3 that flies at high speed by the laser transfer method can be improved in the second disposing step. As a result, the second connecting member (semiconductor chip) can be accurately arranged at a predetermined position on the first connecting member (circuit board) (positional displacement at the time of arrangement of the semiconductor chip is effectively suppressed).

Next, the resin composition 11 is heated to a temperature equal to or higher than the melting point of the solder particles 11A. The resin composition 11 is preferably heated to a temperature equal to or higher than the curing temperature of the thermosetting component 11B (thermosetting compound). During this heating, the solder particles 11A present in the region where no electrode is formed are accumulated between the first electrode 2a and the second electrode 3a (self-condensation effect). In the case of using a conductive paste instead of a conductive film, the solder particles 11A are more effectively gathered between the first electrode 2a and the second electrode 3 a. In addition, the solder particles 11A are melted and bonded to each other. In addition, the thermosetting component 11B is thermally cured. As a result, as shown in fig. 4, the connection portion 4 connecting the first member to be connected (circuit board) 2 and the second member to be connected (semiconductor chip) 3 is formed of the resin composition 11. The connection portion 4 is formed by the resin composition 11, the solder portion 4A is formed by joining the plurality of solder particles 11A, the cured product portion 4B is formed by thermosetting the thermosetting component 11B, and the first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A in the connection portion 4 (connection step). If the solder particles 11A move sufficiently, the temperature may not be kept constant from the start of the movement of the solder particles 11A between the first electrode 2a and the second electrode 3a to the completion of the movement of the solder particles 11A between the first electrode 2a and the second electrode 3 a.

In the second disposing step and the connecting step, it is preferable that pressurization is not performed. In this case, the weight of the second member to be connected (semiconductor chip) 3 is applied to the resin composition 11. Therefore, the solder particles 11A are more effectively gathered between the first electrode 2a and the second electrode 3a when the connection portion 4 is formed. In at least one of the second disposing step and the connecting step, when the pressure is applied, the action between the first electrode 2a and the second electrode 3a, which tends to be inhibited by the solder particles 11A, is increased.

In the present embodiment, since pressurization is not performed, even when the first member to be connected (circuit board) 2 and the second member to be connected (semiconductor chip) 3 overlap each other in a state where the alignment of the first electrode 2a and the second electrode 3a is slightly shifted, the first electrode 2a and the second electrode 3a can be connected by correcting the slight shift (self-alignment effect). This is because, when the area of the self-aggregated molten solder between the first electrode 2a and the second electrode 3a in contact with the other components of the resin composition is minimized, the solder becomes stable in energy, and the force acting as an aligned connection structure having a connection structure with the smallest area acts. In this case, it is preferable that the resin composition is not cured, and the viscosity of the components other than the solder particles of the resin composition is sufficiently low at the temperature and time.

Thus, the connection structure 1 shown in fig. 1 was obtained. The second disposing step and the connecting step may be performed continuously. After the second disposing step, the obtained laminate of the first member to be connected 2, the resin composition 11, and the second member to be connected 3 may be moved to a heating portion, and the connecting step may be performed. For the heating, the laminate may be disposed on a heating member or may be disposed in a space after heating.

In the second disposing step, it is preferable that the second member to be connected is moved onto a surface of the resin composition opposite to the first member to be connected at a speed of 1cm/s or more by a laser transfer method, and the second member to be connected is disposed so that the first electrode faces the second electrode. In the second disposing step, the second member to be connected is preferably moved onto the surface of the resin composition opposite to the first member to be connected by a laser transfer method at a speed of preferably 5cm/s or more, more preferably 10cm/s or more, and still more preferably 50cm/s or more. The upper limit of the speed at which the second member to be connected is moved by the laser transfer method is not particularly limited. In the laser transfer method in the second disposing step, the second member to be connected may be moved to a surface of the resin composition opposite to the first member to be connected at a speed of 500cm/s or less. In the second disposing step, the range of speeds at which the second member to be connected is moved onto the surface of the resin composition opposite to the first member to be connected by the laser transfer method may be set by appropriately selecting the lower limit value and the upper limit value.

The heating temperature in the joining step is preferably 250 ℃ or higher, more preferably 300 ℃ or higher, preferably 450 ℃ or lower, more preferably 400 ℃ or lower, and further preferably 350 ℃ or lower. When the heating temperature in the connection step is equal to or higher than the lower limit and equal to or lower than the upper limit, the solder can be more efficiently arranged on the electrodes, and the conduction reliability between the upper and lower electrodes to be connected can be more effectively improved.

As a heating method in the joining step, there are a method of heating the entire joining structure to a temperature equal to or higher than the melting point of the solder and equal to or higher than the curing temperature of the thermosetting component using a reflow furnace or an oven, and a method of heating only the joining portion of the joining structure locally to a temperature equal to or higher than the melting point of the solder and equal to or higher than the curing temperature of the thermosetting component.

Examples of the device used in the local heating method include a hot plate, a heat gun for applying hot air, a soldering iron, and an infrared heater.

In the case of local heating by the heating plate, the upper surface of the heating plate is preferably formed of a metal having high thermal conductivity directly below the connection portion, and other portions not being heated preferably are formed of a material having low thermal conductivity such as fluorine resin.

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

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 bonded substrate. The first connection object member is preferably a resin film, a flexible printed substrate, a flexible flat cable, or a rigid-flexible bonded substrate. The resin film, the flexible printed board, the flexible flat cable, and the rigid-flexible printed board have high flexibility and relatively light weight. When a conductive film is used for connecting such members to be connected, there is a tendency that solder is less likely to collect on the electrodes. In contrast, by using the conductive paste, even if a resin film, a flexible printed board, a flexible flat cable, or a rigid-flexible connection board is used, the solder is efficiently collected on the electrodes, so that the conduction reliability between the electrodes can be sufficiently improved.

Examples of the electrode provided on the connection target member include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, a SUS electrode, and a tungsten electrode. In the case where the connection target member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode, or a copper electrode. In the case where the member to be connected is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, or a tungsten electrode. In the case where the electrode is an aluminum electrode, the electrode may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of the material of the metal oxide layer include indium oxide doped with a 3-valent metal element, zinc oxide doped with a 3-valent metal element, and the like. Examples of the 3-valent metal element include Sn, al, and Ga.

The support member is not particularly limited. Examples of the support member include a glass substrate, a sapphire substrate, a polysiloxane substrate, a metal substrate, and an organic substrate.

The support film is not particularly limited. Examples of the support film include a polysiloxane resin film, an acrylic resin film, and a polyimide resin film. The support film preferably has an adhesive layer.

In the second arrangement step, the cumulative light amount of the irradiated laser light is preferably 100mJ/cm ² or more, more preferably 150mJ/cm ² or more, still more preferably 200mJ/cm ² or more, preferably 400mJ/cm ² or less, more preferably 350mJ/cm ² or less, still more preferably 300mJ/cm ² or less. When the cumulative light amount of the laser light irradiated in the second arrangement step is equal to or more than the lower limit and equal to or less than the upper limit, the capturing performance of the semiconductor chip which flies at high speed can be further improved.

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

Thermoset component (thermoset compound):

phenol novolac type epoxy compound (mitsubishi chemical company "JER 152")

Bisphenol F type epoxy compound (830-S manufactured by DIC Co., ltd.)

Flux:

benzylamine adipate (first flux (carbon number of main chain: 4), average particle diameter: 10 μm, melting point: 180 ℃ C., prepared in accordance with Synthesis example 1 below)

Benzyl amine glutarate (second flux (carbon number of main chain: 3)), average particle diameter of 10 μm, melting point of 108 ℃, was prepared according to the following Synthesis example 2

Stearylamine azelate (second soldering flux (carbon number of main chain: 7)), average particle diameter: 10 μm, melting point: 110 ℃ C., prepared in accordance with the following Synthesis example 3

Synthesis example 1:

24g of water and 14.612g of adipic acid (Fuji photo-pure chemical Co., ltd.) were added as a reaction solvent to a glass bottle, and the mixture was heated at 100℃for 10 minutes to dissolve the mixture. Then 10.715g of benzylamine (Fuji photo-pure chemical Co., ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. And placing the obtained mixed solution into a refrigerator with the temperature of 5-10 ℃ for one night. The precipitated crystals were separated by filtration, washed with water and dried in vacuo to give benzylamine adipate (average particle diameter: 30 μm). The obtained benzylamine adipate was pulverized by a jet mill to obtain benzylamine adipate having an average particle diameter of 10. Mu.m.

Synthesis example 2:

To a glass bottle, 24g of water and 13.212g of glutaric acid (Fuji photo-pure chemical Co., ltd.) as reaction solvents were added, and the mixture was dissolved at room temperature until it became uniform. Then 10.715g of benzylamine (Fuji photo-pure chemical Co., ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. And placing the obtained mixed solution into a refrigerator with the temperature of 5-10 ℃ for one night. The precipitated crystals were separated by filtration, washed with water and dried in vacuo to give benzyl glutarate salt. The obtained benzyl amine glutarate salt was pulverized by jet mill to obtain benzyl amine glutarate salt having an average particle diameter of 10. Mu.m.

Synthesis example 3:

To a glass bottle were added 24g of water and 9.411g of azelaic acid (Fuji photo-pure chemical Co., ltd.) as reaction solvents, and the mixture was heated at 100℃for 10 minutes to dissolve the mixture. Then 13.476g of stearylamine (manufactured by Fuji photo-pure chemical Co., ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. And placing the obtained mixed solution into a refrigerator with the temperature of 5-10 ℃ for one night. The precipitated crystals were isolated by filtration, washed with water and dried under vacuum to give stearylamine azelate (average particle size: 30 μm). The obtained stearylamine azelate salt was pulverized by a jet mill to obtain benzylamine adipate salt having an average particle diameter of 10. Mu.m.

Thixotropic agents that dissolve the flux:

Thixotropic agent in which glutaric acid is dissolved (Nacalai Tesque corporation "glycerin", glutaric acid 30 wt% glycerin 70 wt%, hydrogen bond term δH14.3 MPa ^1/2 in Hansen solubility parameter of glycerin)

Thixotropic agent:

Ethylene glycol (manufactured by Wako Co., ltd., liquid at 25 ℃ C., hydrogen bond term δH2 12.7MPa ^{1 /2} in Hansen solubility parameter)

1, 3-Propanediol (manufactured by TCI Co., ltd., liquid at 25 ℃ C., hydrogen bond term δH2.9 MPa ^1/2 in Hansen solubility parameter)

Solder particles:

SnAgCu solder particles (solder particles "Sn96.5Ag3Cu0.5" manufactured by Mitsui Metal mining Co., ltd., average particle size of 3 μm were selected out) with a melting point of 220 °c

SnBi solder particles (solder particles having a melting point of 139 ℃ and an average particle diameter of 3 μm were selected from "Sn42Bi58" manufactured by Mitsui Metal mining Co., ltd.)

(Average particle diameter of soldering flux and solder particles)

The average particle diameter of the flux and the solder particles was measured using a laser diffraction particle size distribution measuring apparatus (LA-920, manufactured by horiba corporation).

(Melting Point of solder particles and flux)

The melting points of the solder particles and the flux were calculated using differential scanning calorimetric measurement (DSC). As a Differential Scanning Calorimetric (DSC) apparatus, "EXSTAR DSC7020" manufactured by SII corporation was used.

(Example 1 to 8 and comparative example 1 to 2)

(1) Preparation of resin composition (Anisotropic conductive paste)

The components shown in tables 1 to 3 below were blended in the amounts shown in tables 1 to 3 below to obtain resin compositions (anisotropic conductive pastes).

(2) Production of connection Structure

As a first member to be connected (circuit board), a glass substrate (thickness: 0.7 mm) having a plurality of electrodes (first electrode, copper electrode of 23 μm in the lateral direction×30 μm in the longitudinal direction×12 μm in the thickness, electrode space of 14 μm) on the surface was prepared.

As a second connection target member (semiconductor chip), a micro LED chip (material: gaN, thickness: 0.01 mm) having a plurality of electrodes (second electrode, gold electrode of 20 μm in the lateral direction×20 μm in the longitudinal direction×3 μm in the thickness, inter-electrode space of 10 μm) on the surface was prepared.

A resin composition (anisotropic conductive paste) layer was formed by applying a resin composition (anisotropic conductive paste) immediately after the production to the upper surface of the glass substrate so that the thickness became 10 μm by screen printing. Next, semiconductor chips are laminated on the upper surface of the resin composition (anisotropic conductive paste) layer by a laser transfer method so that electrodes face each other. From this state, heating was performed so that the temperature of the resin composition (anisotropic conductive paste) layer became the melting point of the solder particles 5 seconds after the start of the temperature rise. Further, the resin composition (anisotropic conductive paste) layer was heated to 250 ℃ after 10 seconds from the start of the temperature rise, and cured to obtain a connection structure. During heating, no pressurization was performed.

(Evaluation)

(1) Contact angle with respect to water at 25 °c

For the obtained resin composition, the contact angle with respect to water at 25 ℃ was measured by the method.

(2) Screen printability (coatability)

The obtained resin composition (anisotropic conductive paste) was screen-printed on a glass substrate using a metal mask having an opening size of 114 μm×60 μm and a thickness of 10 μm. For the printed 50-point pattern, the printed surface immediately after printing was observed with a laser microscope, the volume of the resin composition applied to the glass substrate was calculated, and the ratio X (%) of the volume of the resin composition applied to the glass substrate to the volume of each opening of the metal mask was calculated. Screen printability was judged according to the following criteria.

[ Criterion for Screen printability ]

O-ratio X is 50% or more

Ratio X is 40% or more and less than 50%

The delta ratio X is more than 30% and less than 40%

X ratio X is less than 30%

(3) Condensation of solder

In the obtained connection structure (20), when the portions of the first electrode and the second electrode that face each other were observed in the lamination direction of the first electrode, the connection portion, and the second electrode, the ratio of the area of the solder portion disposed in the connection portion to the area of 100% of the area of the portions of the first electrode and the second electrode that face each other was evaluated. The 20 values were averaged to determine the area ratio Y. The cohesiveness of the solder at the time of conductive connection is determined based on the area ratio Y, based on the following criteria.

[ Criterion for determining the cohesiveness of solder ]

O-ratio Y is 70% or more

Ratio Y is 60% or more and less than 70%

The delta ratio Y is more than 50% and less than 60%

X ratio Y is less than 50%

(4) Capacity of semiconductor chip

In "(2) screen printability", the semiconductor chips were moved by a laser transfer method at a speed of 1cm/s onto the surface of the resin composition coated on the glass substrate by screen printing opposite to the glass substrate, and 20 semiconductor chips were arranged so that the first electrode of the glass substrate faced the second electrode of the semiconductor chips. The ratio Z of the number of semiconductor chips captured at a position within + -3 μm from a predetermined position among the 20 semiconductor chips was calculated. The trapping property of the semiconductor chip was determined according to the following criteria.

[ Criterion for determining the Capacity of semiconductor chip ]

O-ratio Z is 70% or more

The ratio Z is 50% or more and less than 70%

X the proportion Z is less than 50%

The results are shown in tables 1 to 3 below.

TABLE 1

TABLE 2

TABLE 3

Drawings

1. 1X

First connecting object member (circuit substrate)

First electrode

Second connection object member (semiconductor chip)

Second electrode

4.4 X. connection part

4A, 4XA

4B. 4XB. Cured product portion

Support member (transfer source substrate)

Support film (transfer source substrate)

Resin composition

Solder particles

Thermoset ingredients

Flux

51. Laser irradiation device

Claims (11)

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 greater than 10 MPa ^1/2 , 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 object member having at least one second electrode on its surface to a surface of the resin composition opposite to the first connection object member by laser transfer, and placing the second connection object member so that the first electrode and the second electrode face each other; and 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.