JP7417396B2 - Conductive material, connected structure, and method for manufacturing connected structure - Google Patents

Description

The present invention relates to conductive materials containing solder particles. The present invention also relates to a connected structure using the above-mentioned conductive material and a method for manufacturing the connected structure.

Solder pastes containing a relatively large amount of solder are known.

Furthermore, anisotropic conductive materials containing a relatively large amount of binder resin compared to solder paste are widely known. Examples of the anisotropic conductive material include anisotropic conductive paste and anisotropic conductive film. In the above anisotropic conductive material, conductive particles are dispersed in a binder resin.

The above-mentioned anisotropic conductive material is used to obtain various connected structures. Examples of connections using the anisotropic conductive material include connections between flexible printed circuit boards and glass substrates (FOG (Film on Glass)), connections between semiconductor chips and flexible printed circuit boards (COF (Chip on Film)), and semiconductor Examples include connection between a chip and a glass substrate (COG (Chip on Glass)), connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)), and the like.

For example, when electrically connecting the electrodes of a flexible printed circuit board and the electrodes of a glass epoxy board using the anisotropic conductive material, the anisotropic conductive material containing conductive particles is placed on the glass epoxy board. do. Next, flexible printed circuit boards are laminated and heated and pressurized. Thereby, the anisotropic conductive material is cured, the electrodes are electrically connected via the conductive particles, and a connected structure is obtained.

Patent Document 1 listed below discloses a conductive adhesive containing a bisphenol A type epoxy resin, a phenoxy resin, a liquid epoxy compound having one or more glycidyl groups in one molecule, and a conductive filler.

Japanese Patent Application Publication No. 11-209716

As a conductive material, a conductive material containing a thermosetting compound and solder particles is known.

When making a conductive connection using a conductive material containing solder particles, a plurality of upper electrodes and a plurality of lower electrodes are electrically connected to make a conductive connection. The solder particles are preferably placed between the upper and lower electrodes, and desirably not between adjacent lateral electrodes. It is desirable that adjacent horizontal electrodes are not electrically connected.

In conventional conductive materials containing thermosetting compounds and solder particles, voids are likely to occur when the conductive material is cured, and voids are likely to remain in the formed solder portions. If voids exist in the solder part, the reliability of conduction between the upper and lower electrodes to be connected will be reduced, or the reliability of the connection between the solder part and the electrodes will be reduced.

An object of the present invention is to provide a conductive material that can suppress voids in solder parts. Another object of the present invention is to provide a connected structure using the above conductive material and a method for manufacturing the connected structure.

According to a broad aspect of the present invention, there is provided a conductive material including a thermosetting compound and a plurality of solder particles, wherein the thermosetting compound includes an aliphatic epoxy compound or an alicyclic epoxy compound, and the thermosetting The total content of the aliphatic epoxy compound and the alicyclic epoxy compound is 0.5% by weight or more and 25% by weight or less in 100% by weight of the compound, and the melting point of the solder particles is 150°C or more and 450°C or less. A conductive material is provided.

In a particular aspect of the conductive material according to the present invention, the solder particles have a melting point of 180°C or more and 350°C or less.

In a particular aspect of the electrically conductive material according to the present invention, the electrically conductive material does not contain a thermosetting agent.

In a particular aspect of the conductive material according to the present invention, the solder particles contain tin, and the tin content is 40% by weight or more and 99.9% by weight or less based on 100% by weight of the metal contained in the solder particles. be.

In a certain aspect of the conductive material according to the present invention, the thermosetting compound includes an aromatic epoxy compound.

In a particular aspect of the conductive material according to the present invention, the content of the aromatic epoxy compound is 75% by weight or more and 99.5% by weight or less in 100% by weight of the thermosetting compound.

In a particular aspect of the conductive material according to the present invention, the conductive material includes a gap material.

In a particular aspect of the conductive material according to the present invention, the conductive material is a conductive paste.

According to a broad aspect of the present invention, a first connection target member having a first electrode on its surface, a second connection target member having a second electrode on its surface, and the first connection target member, a connecting portion connecting the second connection target member, the material of the connecting portion is the above-mentioned conductive material, and the first electrode and the second electrode are connected to the connecting portion. A connection structure is provided that is electrically connected by a solder portion therein.

According to a broad aspect of the present invention, the above-described conductive material is disposed on the surface of a first connection target member having a first electrode on its surface; A second connection target member having a second electrode on its surface is arranged on a surface opposite to the first connection target member side so that the first electrode and the second electrode face each other. forming a connection portion connecting the first connection target member and the second connection target member with the conductive material by heating the conductive material to a temperature equal to or higher than the melting point of the solder particles; There is provided a method for manufacturing a connected structure, comprising the steps of: electrically connecting the first electrode and the second electrode with a solder portion in the connecting portion.

The electrically conductive material according to the present invention includes a thermosetting compound and a plurality of solder particles. In the conductive material according to the present invention, the thermosetting compound includes an aliphatic epoxy compound or an alicyclic epoxy compound, and in 100% by weight of the thermosetting compound, the aliphatic epoxy compound and the alicyclic epoxy compound The total content of the solder particles is 0.5% by weight or more and 25% by weight or less, and the melting point of the solder particles is 150°C or more and 450°C or less. Since the conductive material according to the present invention has the above configuration, voids in the solder portion can be suppressed.

FIG. 1 is a cross-sectional view schematically showing a connected structure obtained using a conductive material according to an embodiment of the present invention. FIGS. 2(a) to 2(c) are cross-sectional views for explaining each step of an example of a method for manufacturing a connected structure using a conductive material according to an embodiment of the present invention. FIG. 3 is a sectional view showing a modification of the connected structure.

The details of the present invention will be explained below.

(conductive material)
The electrically conductive material according to the present invention includes a thermosetting compound and a plurality of solder particles. In the conductive material according to the present invention, the thermosetting compound includes an aliphatic epoxy compound or an alicyclic epoxy compound, and in 100% by weight of the thermosetting compound, the aliphatic epoxy compound and the alicyclic epoxy compound The total content of the solder particles is 0.5% by weight or more and 25% by weight or less, and the melting point of the solder particles is 150°C or more and 450°C or less.

Since the conductive material according to the present invention has the above configuration, voids in the solder portion can be suppressed. With the conductive material according to the present invention, the reliability of conduction between the upper and lower electrodes to be connected can be effectively improved, and the reliability of the connection between the solder portion and the electrodes can be further improved.

The conductive material according to the present invention contains a specific content of an aliphatic epoxy compound or an alicyclic epoxy compound as a thermosetting compound. Therefore, in the conductive material according to the present invention, the curing speed of the conductive material can be made slower than that of a conductive material that does not contain both an aliphatic epoxy compound and an alicyclic epoxy compound. Furthermore, the conductive material according to the present invention includes solder particles having a relatively high melting point. Therefore, for example, even when the content of the thermosetting agent is small or when the thermosetting agent is not included, the conductive material can be cured well and at an appropriate curing speed. . In this way, the conductive material according to the present invention can have a relatively slow curing speed compared to conventional conductive materials, so even if voids occur when the conductive material is cured, It is easy for voids to be removed during the soldering process, and as a result, voids in the solder portion can be suppressed.

Furthermore, in the present invention, positional displacement between the electrodes can be prevented. In the present invention, when the second connection target member is superimposed on the first connection target member having a conductive material disposed on the upper surface, the electrodes of the first connection target member and the second connection target member are connected to each other. Even in a state where the alignment is misaligned, the misalignment can be corrected and the electrodes can be connected to each other (self-alignment effect).

From the viewpoint of disposing the solder on the electrodes more efficiently, the conductive material is preferably liquid at 25° C., and is preferably a conductive paste. Preferably, the conductive material is a conductive paste at 25°C.

From the viewpoint of disposing the solder on the electrode more efficiently, the viscosity (η25) at 25°C of the conductive material immediately after production is preferably 10 Pa·s or more, more preferably 20 Pa·s or more, and even more preferably is 30 Pa·s or more, preferably 250 Pa·s or less, more preferably 200 Pa·s or less. The above viscosity (η25) can be adjusted as appropriate depending on the types and amounts of the ingredients.

The viscosity (ηA) of the conductive material at 25 °C immediately after the frozen stored conductive material is thawed and reaches 25 °C is preferably 20 Pa·s or more, more preferably 30 Pa·s or more, and preferably It is 250 Pa·s or less, more preferably 200 Pa·s or less. When the viscosity (ηA) is not less than the lower limit and not more than the upper limit, the solder can be placed on the electrodes more efficiently, and the continuity reliability between the upper and lower electrodes to be connected can be further effectively improved. can be increased to The above viscosity (ηA) can be adjusted as appropriate depending on the types and amounts of the ingredients.

The viscosity (η25) and the viscosity (ηA) can be measured at 25° C. and 5 rpm using, for example, an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.).

Note that in this specification, the conditions for frozen storage of the conductive material for measuring viscosity are the conditions for storing it at -40° C. for 7 days. On the other hand, the conditions for frozen storage during actual use of the conductive material are not particularly limited. The temperature at which the electrically conductive material is stored frozen during actual use is not particularly limited, as long as it is below 0°C. The temperature of the frozen storage during actual use of the conductive material may be -10°C or lower, -20°C or lower, or -40°C or lower. The period of frozen storage during actual use of the conductive material is not particularly limited, and may be 180 days or less. The period of frozen storage may be 30 days or more, 60 days or more, 90 days or more, or 120 days or more.

Furthermore, in this specification, the thawing conditions for the conductive material for measuring viscosity are storage conditions at 25°C. On the other hand, there are no particular limitations on the method for thawing the frozen stored conductive material when the conductive material is actually used. Examples of methods for thawing the frozen conductive material during actual use include thawing at room temperature, thawing under refrigerated conditions, and thawing under heating conditions. . The above room temperature condition is preferably 20°C or more and 25°C or less. The above-mentioned refrigeration conditions are preferably higher than 0°C and lower than or equal to 10°C. The heating conditions are preferably 30°C or higher and 35°C or lower.

The viscosity (ηmp) of the conductive material at the melting point of the solder particles is preferably 50 Pa·s or less, more preferably 10 Pa·s or less, even more preferably 1 Pa·s or less, preferably 0.1 Pa·s or more, More preferably, it is 0.2 Pa·s or more. When the viscosity (ηmp) is less than or equal to the upper limit, the solder can be disposed on the electrode even more efficiently. When the viscosity (ηmp) is equal to or higher than the lower limit, voids at the connection portion can be suppressed, and the conductive material can be prevented from protruding outside the connection portion.

The above viscosity (ηmp) was measured using STRESSTECH (manufactured by REOLOGICA), etc., with strain control of 1 rad, frequency of 1 Hz, temperature increase rate of 20 °C/min, and measurement temperature range of 25 °C to 200 °C (however, the liquidus line of the solder particles When the temperature (melting point) exceeds 200° C., measurement can be performed under the condition that the upper temperature limit is the liquidus temperature (melting point) of the solder particles. From the measurement results, the viscosity at the melting point (°C) of the solder particles is evaluated.

The above-mentioned conductive material 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. From the viewpoint of arranging the solder on the electrodes more efficiently, the conductive material is preferably a conductive paste. The above-mentioned conductive material is suitably used for electrical connection of electrodes. Preferably, the conductive material is a circuit connection material.

Each component contained in the above conductive material will be explained below. In addition, in this specification, "(meth)acrylic" means one or both of "acrylic" and "methacrylic."

(solder particles)
The conductive material includes solder particles. Both the center portion and the outer surface of the solder particles are made of solder. The solder particles described above are particles in which both the center portion and the outer surface are solder. When conductive particles comprising base particles made of a material other than solder and a solder portion disposed on the surface of the base particles are used instead of the solder particles described above, conductive particles can be placed on the electrodes. Particles become difficult to collect. In addition, since the conductive particles described above have low solder bondability between conductive particles, the conductive particles that have moved onto the electrode tend to move out of the electrode, and the effect of suppressing misalignment between the electrodes is also low. tends to be lower.

From the viewpoint of effectively exhibiting the effects of the present invention, the melting point of the solder particles is 150°C or more and 450°C or less. The melting point of the solder particles is preferably 180°C or higher, more preferably 190°C or higher, even more preferably 200°C or higher, and preferably 350°C or lower, more preferably 300°C or lower, and even more preferably 250°C or lower. . If the melting point of the solder particles is above the above lower limit and below the above upper limit, even if the content of the thermosetting agent in the conductive material is small or the conductive material does not contain a thermosetting agent, the conductive material will be It can be cured well and at an appropriate curing rate. Therefore, even if voids occur when the conductive material is cured, the voids are likely to be removed before the conductive material is cured, and as a result, voids in the solder portion can be effectively suppressed.

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

The solder is preferably a metal having a melting point of 450° C. or lower (low melting point metal). The solder particles are preferably metal particles having a melting point of 450° C. or lower (low-melting point metal particles). The low melting point metal particles are particles containing a low melting point metal. The low melting point metal refers to a metal having a melting point of 450° C. or lower. The melting point of the low melting point metal is preferably 150°C or higher, more preferably 180°C or higher, even more preferably 190°C or higher, particularly preferably 200°C or higher, preferably 350°C or lower, more preferably 300°C or lower, and Preferably it is 250°C or lower.

Further, it is preferable that the solder particles contain tin. Out of 100% by weight of metal contained in the solder particles, the content of tin is preferably 30% by weight or more, more preferably 40% by weight or more, even more preferably 70% by weight or more, still more preferably 90% by weight or more, It is even more preferably 92% by weight or more, particularly preferably 95% by weight or more. The content of tin in 100% by weight of metal contained in the solder particles is preferably 99.9% by weight or less, more preferably 99% by weight or less. When the content of tin in the solder particles is not less than the above lower limit and not more than the above upper limit, the connection reliability between the solder part and the electrode becomes even higher.

The tin content is measured using a high-frequency inductively coupled plasma emission spectrometer (ICP-AES manufactured by Horiba) or a fluorescent X-ray analyzer (EDX-800HS manufactured by Shimadzu Corporation). can do.

By using the above-mentioned solder particles, the solder melts and joins to the electrodes, and the solder portion establishes conduction between the electrodes. For example, since the solder portion and the electrode tend to make surface contact rather than point contact, the connection resistance becomes low. Furthermore, the use of the solder particles increases the bonding strength between the solder part and the electrode, making it even more difficult for the solder part to separate from the electrode, resulting in even higher conduction reliability and connection reliability.

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, since they have excellent wettability to the electrode. More preferably, the low melting point metal is a tin-bismuth alloy or a tin-indium alloy.

The solder particles are preferably filler metals whose liquidus line is 450° C. or less based on JIS Z3001: Welding terminology. Examples of the composition of the solder particles include metal compositions containing zinc, gold, silver, lead, copper, tin, bismuth, indium, and the like. Preferred are tin-indium (117° C. eutectic) or tin-bismuth (139° C. eutectic) which have a low melting point and are lead-free. That is, the solder particles preferably do not contain lead, and preferably contain tin and indium, or tin and bismuth.

From the viewpoint of exhibiting the effects of the present invention even more effectively, the solder particles preferably contain tin and silver, or contain tin and copper, and preferably contain tin, silver, and copper. More preferred.

In order to further increase the bonding strength between the solder part and the electrode, the solder particles include nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, chromium, It may also contain metals such as molybdenum and palladium. Moreover, from the viewpoint of further increasing the bonding strength between the solder part and the electrode, it is preferable that the solder particles contain nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further increasing the bonding strength between the solder part and the electrode, the content of these metals for increasing the bonding strength is preferably 0.0001% by weight or more based on 100% by weight of the metal contained in the solder particles, Preferably it is 1% by weight or less.

The average particle diameter of the solder particles is preferably 2 μm or more, more preferably 5 μm or more, and preferably 30 μm or less, more preferably 10 μm or less. When the average particle diameter of the solder particles is not less than the above lower limit and not more than the above upper limit, the solder can be arranged on the electrodes even more efficiently, and the reliability of conduction between the upper and lower electrodes to be connected can be improved.

The average particle diameter of the solder particles is preferably a number average particle diameter. The average particle size of the solder particles can be determined, for example, by observing 50 arbitrary solder particles with an electron microscope or optical microscope and calculating the average value of the particle size of each solder particle, or by performing laser diffraction particle size distribution measurement. It is required by

Further, methods for adjusting the average particle diameter of the solder particles to the above-mentioned preferred range include a method of pulverizing the solder particles with a jet mill or the like, a method of sieving with a sieve, etc.

The coefficient of variation (CV value) of the particle diameter of the solder particles is preferably 5% or more, more preferably 10% or more, and preferably 40% or less, more preferably 30% or less. When the coefficient of variation of the particle diameter of the solder particles is greater than or equal to the lower limit and less than or equal to the upper limit, the solder can be disposed on the electrode even more efficiently. However, the CV value of the particle diameter of the solder particles may be less than 5%.

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

CV value (%) = (ρ/Dn) x 100
ρ: Standard deviation of particle diameter of solder particles Dn: Average value of particle diameter of solder particles

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

The content of the solder particles in 100% by weight of the conductive material is preferably 40% by weight or more, more preferably 60% by weight or more, further preferably 80% by weight or more, particularly preferably 88% by weight or more, and preferably is 95% by weight or less, more preferably 93% by weight or less, even more preferably 90% by weight or less. When the content of the solder particles is more than the above lower limit and less than the above upper limit, the solder can be placed on the electrodes even more efficiently, it is easy to place a large amount of solder between the electrodes, and the continuity is reliable. It is possible to improve sex even more effectively. From the viewpoint of further improving conduction reliability, it is preferable that the content of the solder particles is large.

(Thermosetting component: thermosetting compound)
The electrically conductive material according to the present invention contains a thermosetting compound as a thermosetting component. The thermosetting compound is a compound that can be cured by heating.

Examples of the thermosetting compound include oxetane compounds, epoxy compounds, episulfide compounds, (meth)acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. The above thermosetting compounds may be used alone or in combination of two or more.

The conductive material according to the present invention includes an epoxy compound, and the epoxy compound includes an aliphatic epoxy compound or an alicyclic epoxy compound. In the conductive material according to the present invention, the thermosetting compound includes an aliphatic epoxy compound or an alicyclic epoxy compound. The conductive material according to the present invention may contain an aliphatic epoxy compound, a cycloaliphatic epoxy compound, or both an aliphatic epoxy compound and an alicyclic epoxy compound. .

From the viewpoint of exhibiting the effects of the present invention even more effectively, in the conductive material according to the present invention, it is preferable that the thermosetting compound contains an aromatic epoxy compound.

The above-mentioned epoxy compounds are classified into any one of aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds.

Examples of the aliphatic epoxy compounds include 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, and neopentyl glycol diglycidyl ether. The above aliphatic epoxy compounds may be used alone or in combination of two or more.

Examples of the alicyclic epoxy compounds include dicyclopentadiene type epoxy compounds, epoxy compounds having an adamantane skeleton, epoxy compounds having a tricyclodecane skeleton, naphthylene ether type epoxy compounds, 3',4'-epoxycyclohexylmethyl-3 , 4-epoxycyclohexane carboxylate, 1,2-epoxy-4-vinylcyclohexane, and 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol. etc. Note that the alicyclic epoxy compound may have a double bond in a part of the ring. Only one kind of the above-mentioned alicyclic epoxy compound may be used, or two or more kinds thereof may be used in combination.

Examples of the aromatic epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, phenol novolac type epoxy compounds, biphenyl type epoxy compounds, biphenyl novolac type epoxy compounds, biphenol type epoxy compounds, and naphthalene type epoxy compounds. Examples include epoxy compounds, fluorene type epoxy compounds, phenol aralkyl type epoxy compounds, naphthol aralkyl type epoxy compounds, anthracene type epoxy compounds, and epoxy compounds having a triazine nucleus in the skeleton. The above-mentioned aromatic epoxy compounds may be used alone or in combination of two or more.

From the viewpoint of exhibiting the effects of the present invention even more effectively, the aliphatic epoxy compound is preferably 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, or neopentyl glycol diglycidyl ether. , neopentyl glycol diglycidyl ether is more preferred. Furthermore, by using these preferable aliphatic epoxy compounds, the solder can be more efficiently placed on the electrodes, and the reliability of conduction between the upper and lower electrodes to be connected can be further effectively increased. Furthermore, discoloration of the thermosetting compound can be suppressed even more effectively.

From the viewpoint of exhibiting the effects of the present invention even more effectively, the above-mentioned alicyclic epoxy compounds include 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 1,2-epoxy-4 -vinylcyclohexane or 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol is preferable, and 2,2-bis(hydroxymethyl) More preferably, it is a 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of -1-butanol. In addition, by using these preferable alicyclic epoxy compounds, it is possible to more efficiently arrange the solder on the electrodes, and the reliability of conduction between the upper and lower electrodes to be connected is further effectively increased. Furthermore, discoloration of the thermosetting compound can be suppressed even more effectively.

From the viewpoint of exhibiting the effects of the present invention even more effectively, the aromatic epoxy compound is preferably a bisphenol F-type epoxy compound, a phenol novolac-type epoxy compound, or a biphenyl-type epoxy compound, and a biphenyl-type epoxy compound It is more preferable that Furthermore, by using these preferable aromatic epoxy compounds, the solder can be placed on the electrodes more efficiently, and the reliability of conduction between the upper and lower electrodes to be connected can be further effectively increased. Furthermore, discoloration of the thermosetting compound can be suppressed even more effectively.

The above epoxy compound (aliphatic epoxy compound, alicyclic epoxy compound, aromatic epoxy compound) is liquid or solid at room temperature (25°C), and when the above epoxy compound is solid at room temperature, the above epoxy compound The melting temperature of the solder particles is preferably equal to or lower than the melting point of the solder particles. By using the above preferable epoxy compound, the viscosity is high at the stage where the connection target members are bonded together, and when acceleration is applied due to impact such as transportation, the first connection target member and the second connection target member are bonded together. Misalignment with the member can be suppressed. Furthermore, the viscosity of the conductive material can be greatly reduced by the heat during curing, and the aggregation of the solder during conductive connection can proceed efficiently.

From the viewpoint of exhibiting the effects of the present invention, in the conductive material according to the present invention, the total content of the aliphatic epoxy compound and the alicyclic epoxy compound is 0.5% by weight in 100% by weight of the thermosetting compound. % or more and 25% or less by weight. If the above-mentioned total content is less than 0.5% by weight, the curing speed of the conductive material will not be slowed down sufficiently, and if voids are generated during curing of the conductive material, it will be difficult to remove the voids. If the total content exceeds 25% by weight, the insulation reliability between the electrodes or the continuity reliability between the electrodes may decrease. In addition, when the above thermosetting compound contains the above aliphatic epoxy compound and does not contain the above alicyclic epoxy compound, the total content of the above aliphatic epoxy compound and the above alicyclic epoxy compound is It means the content of group epoxy compounds. When the thermosetting compound contains the alicyclic epoxy compound and does not contain the aliphatic epoxy compound, the total content of the aliphatic epoxy compound and the alicyclic epoxy compound is It means the content of epoxy compound.

The total content of the aliphatic epoxy compound and the alicyclic epoxy compound in 100% by weight of the thermosetting compound is preferably 1% by weight or more, more preferably 5% by weight or more, and still more preferably 8% by weight. or more, preferably 20% by weight or less, more preferably 10% by weight or less. When the above-mentioned total content is at least the above-mentioned lower limit and below the above-mentioned upper limit, the effects of the present invention can be exhibited even more effectively. In addition, if the total content is below the upper limit above, the solder can be placed on the electrodes more efficiently, the insulation reliability between the electrodes can be further effectively increased, and the conduction reliability between the electrodes can be improved. It is possible to improve sex even more effectively.

The content of the aromatic epoxy compound in 100% by weight of the thermosetting compound is preferably 75% by weight or more, more preferably 80% by weight or more, still more preferably 90% by weight or more, and preferably 99.5% by weight or more. It is at most 99% by weight, more preferably at most 95% by weight, particularly preferably at most 92% by weight. When the content of the aromatic epoxy compound is at most the above upper limit, the effects of the present invention can be exhibited even more effectively. In addition, when the content of the aromatic epoxy compound is below the upper limit, the solder can be more efficiently arranged on the electrodes, the insulation reliability between the electrodes can be further effectively increased, and the The conduction reliability can be further effectively improved.

The thermosetting compound may contain a thermosetting compound other than the epoxy compound.

The content of the thermosetting compound in 100% by weight of the conductive material is preferably 5% by weight or more, more preferably 8% by weight or more, even more preferably 10% by weight or more, and preferably 60% by weight or less, The content is more preferably 40% by weight or less, further preferably 20% by weight or less, particularly preferably 12% by weight or less. When the content of the thermosetting compound is not less than the lower limit and not more than the upper limit, the solder can be more efficiently placed on the electrodes, and the insulation reliability between the electrodes can be further effectively improved. The reliability of conduction between the electrodes can be further effectively improved. From the viewpoint of increasing impact resistance even more effectively, it is preferable that the content of the thermosetting compound is as large as possible.

The content of the epoxy compound in 100% by weight of the conductive material is preferably 5% by weight or more, more preferably 8% by weight or more, even more preferably 10% by weight or more, and preferably 60% by weight or less, more preferably is 40% by weight or less, more preferably 20% by weight or less, particularly preferably 12% by weight or less. When the content of the epoxy compound is at least the above lower limit and below the above upper limit, the solder can be more efficiently arranged on the electrodes, the insulation reliability between the electrodes can be further effectively increased, and the The conduction reliability can be further effectively improved. From the viewpoint of further improving impact resistance, it is preferable that the content of the epoxy compound is as large as possible.

The total content of the aliphatic epoxy compound and the alicyclic epoxy compound in 100% by weight of the conductive material is preferably 0.1% by weight or more, more preferably 0.6% by weight or more, and still more preferably 1% by weight or more. .1% by weight or more. The total content of the aliphatic epoxy compound and the alicyclic epoxy compound in 100% by weight of the conductive material is preferably 2.3% by weight or less, more preferably 1.7% by weight or less, and still more preferably 1% by weight or less. .3% by weight or less, particularly preferably 1.2% by weight or less. When the above-mentioned total content is at least the above-mentioned lower limit and below the above-mentioned upper limit, the effects of the present invention can be exhibited even more effectively. In addition, if the total content is below the upper limit above, the solder can be placed on the electrodes more efficiently, the insulation reliability between the electrodes can be further effectively increased, and the conduction reliability between the electrodes can be improved. It is possible to improve sex even more effectively.

The content of the aromatic epoxy compound in 100% by weight of the conductive material is preferably 5% by weight or more, more preferably 8% by weight or more, even more preferably 10% by weight or more, and preferably 60% by weight or less, The content is more preferably 40% by weight or less, further preferably 20% by weight or less, particularly preferably 12% by weight or less. When the content of the aromatic epoxy compound is at most the above upper limit, the effects of the present invention can be exhibited even more effectively. In addition, when the content of the aromatic epoxy compound is below the upper limit, the solder can be more efficiently arranged on the electrodes, the insulation reliability between the electrodes can be further effectively increased, and the The conduction reliability can be further effectively improved.

(Thermosetting component: thermosetting agent)
The conductive material may or may not contain a thermosetting agent. The conductive material may contain a thermosetting agent together with the thermosetting compound. The thermosetting agent thermosets the thermosetting compound.

The above thermosetting agent is not particularly limited. Examples of the thermosetting agent include imidazole curing agents, phenol curing agents, thiol curing agents, amine curing agents, acid anhydride curing agents, thermal cation initiators, thermal radical generators, and the like. The above thermosetting agents may be used alone or in combination of two or more.

From the viewpoint of enabling the conductive material to be cured more rapidly at low temperatures, the thermosetting agent is preferably an imidazole curing agent, a thiol curing agent, or an amine curing agent. Further, from the viewpoint of improving the storage stability when the thermosetting compound and the thermosetting agent are mixed, the thermosetting agent is preferably a latent curing agent. Preferably, the latent curing agent is a latent imidazole curing agent, a latent thiol curing agent or a latent amine curing agent. Note that the thermosetting agent may be coated with a polymeric substance such as polyurethane resin or polyester resin.

The above imidazole curing agent is not particularly limited. Examples of the imidazole curing agent include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6 -[2'-Methylimidazolyl-(1')]-ethyl-s-triazine and 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct , 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2-paratolyl-4-methyl-5 -5-position of 1H-imidazole in hydroxymethylimidazole, 2-metatolyl-4-methyl-5-hydroxymethylimidazole, 2-metatolyl-4,5-dihydroxymethylimidazole, 2-paratolyl-4,5-dihydroxymethylimidazole, etc. Examples include imidazole compounds in which hydrogen at the 2-position is substituted with a hydroxymethyl group and hydrogen at the 2-position is substituted with a phenyl group or a tolyl group.

The above-mentioned thiol curing agent is not particularly limited. Examples of the thiol curing agent include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate.

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

The acid anhydride curing agent is not particularly limited, and any acid anhydride that can be used as a curing agent for thermosetting compounds such as epoxy compounds can be used. The acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride. , anhydrides of phthalic acid derivatives, maleic anhydride, nadic anhydride, methyl nadic anhydride, glutaric anhydride, succinic anhydride, glycerin bis-trimellitic anhydride monoacetate, and difunctional compounds such as ethylene glycol bis-trimellitic anhydride. trifunctional acid anhydride curing agents such as trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, methylcyclohexenetetracarboxylic anhydride, polyazelaic anhydride, etc. Examples include acid anhydride curing agents having four or more functional groups.

The thermal cationic initiator is not particularly limited. Examples of the thermal cationic initiator include iodonium-based cationic curing agents, oxonium-based cationic curing agents, and sulfonium-based cationic curing agents. Examples of the iodonium-based cationic curing agent include bis(4-tert-butylphenyl)iodonium hexafluorophosphate. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate. Examples of the sulfonium-based cationic curing agent include tri-p-tolylsulfonium hexafluorophosphate.

The thermal radical generator described above is not particularly limited. Examples of the thermal radical generator include azo compounds and organic peroxides. Examples of the azo compound include azobisisobutyronitrile (AIBN) and the like. Examples of the organic peroxide include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

The reaction initiation temperature of the thermosetting agent is preferably 50°C or higher, more preferably 70°C or higher, even more preferably 80°C or higher, preferably 250°C or lower, more preferably 200°C or lower, and even more preferably 150°C. The temperature below is particularly preferably 140°C or below. When the reaction start temperature of the thermosetting agent is equal to or higher than the lower limit and lower than the upper limit, the solder can be disposed on the electrode more efficiently. From the viewpoint of arranging the solder on the electrodes more efficiently and from the viewpoint of further effectively increasing the reliability of conduction between the upper and lower electrodes to be connected, the reaction initiation temperature of the thermosetting agent is 80°C. As mentioned above, it is particularly preferable that the temperature is 140°C or less.

The reaction start temperature of the thermosetting agent means the temperature at which the exothermic peak starts rising in DSC. Examples of the DSC device include "EXSTAR DSC7020" manufactured by SII.

Preferably, the conductive material does not contain the thermosetting agent. When the conductive material does not contain the thermosetting agent, the curing speed of the conductive material can be slowed down. Therefore, even if voids occur when the conductive material is cured, the voids are likely to be removed before the conductive material is cured, and as a result, voids in the solder portion can be suppressed.

However, the conductive material may contain the thermosetting agent. When the conductive material contains the thermosetting agent, the content of the thermosetting agent is not particularly limited. With respect to 100 parts by weight of the thermosetting compound, the content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, and preferably 200 parts by weight or less, more preferably The amount is 100 parts by weight or less, more preferably 75 parts by weight or less. When the content of the thermosetting agent is equal to or higher than the lower limit, it is easy to sufficiently cure the conductive material. When the content of the thermosetting agent is below the above upper limit, it becomes difficult for excess thermosetting agent that did not take part in curing to remain after curing, and the heat resistance of the cured product becomes even higher.

(Thermosetting component: curing accelerator)
The conductive material may or may not contain a curing accelerator. The above-mentioned curing accelerator is not particularly limited. The curing accelerator preferably acts as a curing catalyst in the reaction between the thermosetting compound and the thermosetting agent. The curing accelerator preferably acts as a curing catalyst in the reaction with the thermosetting compound. As for the said hardening accelerator, only 1 type may be used, and 2 or more types may be used together.

Examples of the curing accelerator include phosphonium salts, tertiary amines, tertiary amine salts, quaternary onium salts, tertiary phosphines, crown ether complexes, amine complex compounds, and phosphonium ylides. Specifically, the curing accelerators include imidazole compounds, isocyanurates of imidazole compounds, dicyandiamide, derivatives of dicyandiamide, melamine compounds, derivatives of melamine compounds, diaminomaleonitrile, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine. , bis(hexamethylene)triamine, triethanolamine, diaminodiphenylmethane, amine compounds such as organic acid dihydrazide, 1,8-diazabicyclo[5,4,0]undecene-7,3,9-bis(3-aminopropyl) -2,4,8,10-tetraoxaspiro[5,5]undecane, boron trifluoride, boron trifluoride-amine complex compounds, triphenylphosphine, tricyclohexylphosphine, tributylphosphine, methyldiphenylphosphine, etc. Examples include organic phosphorus compounds such as

The above phosphonium salt is not particularly limited. The above phosphonium salts include tetra-n-butylphosphonium bromide, tetra-n-butylphosphonium O-O diethyldithiophosphate, methyltributylphosphonium dimethyl phosphate, tetra-n-butylphosphonium benzotriazole, tetra-n-butylphosphonium tetrafluoroborate, and tetra-n-butyl phosphonium. Examples include phosphonium tetraphenylborate.

It is preferable that the conductive material does not contain the curing accelerator. When the conductive material does not contain the curing accelerator, the curing speed of the conductive material can be slowed down. Therefore, even if voids occur when the conductive material is cured, the voids are likely to be removed before the conductive material is cured, and as a result, voids in the solder portion can be suppressed.

However, the conductive material may contain the curing accelerator. When the conductive material contains the curing accelerator, the content of the curing accelerator is not particularly limited. The content of the curing accelerator relative to 100 parts by weight of the thermosetting compound is preferably 0.5 parts by weight or more, more preferably 0.8 parts by weight or more, and preferably 10 parts by weight or less, more preferably 8 parts by weight. Parts by weight or less. When the content of the curing accelerator is at least the above lower limit and at most the above upper limit, the thermosetting compound can be cured well. In addition, when the content of the curing accelerator is at least the above lower limit and below the above upper limit, the solder can be placed on the electrodes even more efficiently, and the continuity reliability between the upper and lower electrodes to be connected is improved. It can be improved even more effectively.

(gap material)
Preferably, the conductive material includes a gap material. The gap material is a gap material for ensuring a gap between two members during conductive connection. The gap material contacts the two members during conductive connection. At the time of conductive connection, the solder particles can be arranged in the space secured by the gap material so that one solder particle does not touch both of the two members. The gap material preferably has a particle shape. The gap material is preferably gap particles.

The above-mentioned gap material is not particularly limited. Examples of the gap material include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, and metal particles. The gap material may be solder particles. The material of the solder particles serving as the gap material may be the above-mentioned materials. When the gap material is the solder particles described above, the solder particles and the solder particles used as the gap material have different average particle diameters. When the gap material is the solder particles described above, the average particle diameter of the solder particles is smaller than the average particle diameter of the solder particles used as the gap material. When the gap material is the solder particle described above, it is preferable that the solder particle has the preferable configuration described in the column of (Solder particle) above, except for the average particle diameter.

When the gap material is a solder particle, from the viewpoint of effectively expressing its function as a gap material, the melting point of the solder particle that is the gap material is preferably higher than the melting point of the solder particle that is not the gap material. .

When the gap material is not a solder particle, the melting point of the gap material is preferably equal to or higher than the melting point of the solder particles, preferably exceeds the melting point of the solder particles, and preferably exceeds the melting point of the solder particles by 10°C or more. preferable.

From the viewpoint of arranging the solder on the electrode more efficiently and from the viewpoint of controlling the spacing between members with higher precision, the gap material is preferably resin particles or metal particles. The gap material may be a core-shell particle comprising a core and a shell disposed on the surface of the core. The core may be an organic core, and the shell may be an inorganic shell.

Various organic substances are suitably used as materials for the resin particles. Materials for the resin particles include, for example, polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polycarbonate, polyamide, Phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, Examples include polyimide, polyamideimide, polyetheretherketone, polyethersulfone, divinylbenzene polymer, and divinylbenzene copolymer. Examples of the divinylbenzene copolymers include divinylbenzene-styrene copolymers and divinylbenzene-(meth)acrylic acid ester copolymers. Since the hardness of the resin particles can be easily controlled within a suitable range, the material of the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having ethylenically unsaturated groups. is preferred.

When the above-mentioned resin particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, the polymerizable monomer having an ethylenically unsaturated group may be a non-crosslinkable monomer. Examples include crosslinkable monomers.

Examples of the non-crosslinkable monomer include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, and maleic anhydride; Methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, Alkyl (meth)acrylate compounds such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, glycerol (meth)acrylate, polyoxyethylene (meth)acrylate, and glycidyl (meth)acrylate Oxygen atom-containing (meth)acrylate compounds such as; nitrile-containing monomers such as (meth)acrylonitrile; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; vinyl acetate, vinyl butyrate, vinyl laurate, and stearic acid. Acid vinyl ester compounds such as vinyl; unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; trifluoromethyl (meth)acrylate, pentafluoroethyl (meth)acrylate, vinyl chloride, vinyl fluoride, and chlorostyrene, etc. Examples include halogen-containing monomers.

Examples of the crosslinkable monomer include tetramethylolmethanetetra(meth)acrylate, tetramethylolmethanetri(meth)acrylate, tetramethylolmethanedi(meth)acrylate, trimethylolpropanetri(meth)acrylate, dipenta Erythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate Polyfunctional (meth)acrylate compounds such as acrylate, (poly)tetramethylene glycol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate; triallyl(iso)cyanurate, triallyl trimellitate, divinylbenzene , diallyl phthalate, diallylacrylamide, diallyl ether, and silane-containing monomers such as γ-(meth)acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, and vinyltrimethoxysilane.

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

When the base particles are inorganic particles excluding metals or organic-inorganic hybrid particles, examples of the inorganic substance for forming the base particles include silica, alumina, barium titanate, zirconia, and carbon black. Preferably, the inorganic substance is not a metal. The particles formed from the silica are not particularly limited, but for example, after hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, baking may be performed as necessary. Examples include particles obtained by Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed from a crosslinked alkoxysilyl polymer and an acrylic resin.

The organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell disposed on the surface of the core. Preferably, the core is an organic core. Preferably, the shell is an inorganic shell. From the viewpoint of effectively lowering the connection resistance between electrodes, the base particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell disposed on the surface of the organic core.

Examples of the material for the organic core include the materials for the resin particles described above.

Examples of the material for the inorganic shell include the inorganic substances mentioned above as the material for the base particle. The material of the inorganic shell is preferably silica. The inorganic shell is preferably formed by forming a metal alkoxide into a shell-like material by a sol-gel method on the surface of the core, and then firing the shell-like material. Preferably, the metal alkoxide is a silane alkoxide. The inorganic shell is preferably formed of silane alkoxide.

When the base particles are metal particles, examples of the metal that is the material of the metal particles include silver, copper, nickel, silicon, gold, tin, and titanium. Further, the metal particles may be the solder particles described above.

The ratio of the average diameter of the gap material to the average particle diameter of the solder particles (average diameter of gap material/average particle diameter of solder particles) is preferably 3 or more, more preferably 7 or more, and preferably 30 or less. , more preferably 17.5 or less. When the above ratio (average diameter of gap material/average particle diameter of solder particles) is greater than or equal to the above lower limit and less than or equal to the above upper limit, solder can be placed on the electrode even more efficiently, and the spacing between the members can be reduced. It is possible to control with even higher precision.

The average diameter of the gap material is preferably 2 μm or more, more preferably 10 μm or more, and preferably 100 μm or less, more preferably 60 μm or less, and still more preferably 35 μm or less. The average diameter of the gap material is preferably larger than the average particle diameter of the solder particles described above. When the average diameter of the gap material is not less than the lower limit and not more than the upper limit, the solder can be placed on the electrode more efficiently, and the continuity reliability and connection reliability can be further effectively increased. I can do it. It is particularly preferable that the average diameter of the gap material is 10 μm or more and 35 μm or less. When the average diameter of the gap material is 10 μm or more and 35 μm or less, the solder can be more efficiently disposed on the electrode, and the conduction reliability and connection reliability can be further effectively improved.

The average diameter of the gap material is more preferably a number average diameter. The average diameter of the above-mentioned gap material can be determined, for example, by observing 50 arbitrary gap materials with an electron microscope or optical microscope and calculating the average value of the particle diameter of each gap material, or by performing laser diffraction particle size distribution measurement. It is required by When the gap material is a particle, the average diameter of the gap material is the average particle diameter.

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

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

CV value (%) = (ρ/Dn) x 100
ρ: Standard deviation of particle diameter of gap material Dn: Average value of particle diameter of gap material

The shape of the gap material is not particularly limited. The shape of the gap material may be spherical, a shape other than spherical, or a flat shape.

The content of the gap material in 100% by weight of the conductive material is preferably 0.1% by weight or more, more preferably 1% by weight or more, even more preferably 2% by weight or more, and preferably 20% by weight or less, More preferably, it is 10% by weight or less. When the content of the gap material is at least the above lower limit and below the above upper limit, solder can be placed on the electrodes even more efficiently, it is easy to place a large amount of solder between the electrodes, and conduction is ensured. Reliability and insulation reliability can be improved even more effectively.

(flux)
Preferably, the conductive material includes flux. By using flux, solder can be placed on the electrodes more efficiently. The above flux is not particularly limited. As the above-mentioned flux, a flux commonly used for soldering and the like can be used.

The above fluxes 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 halide, hydrazine, an amine compound, an organic acid and Examples include pine resin. The above fluxes may be used alone or in combination of two or more.

Examples of the molten salt include ammonium chloride. Examples of the organic acids include lactic acid, citric acid, stearic acid, glutamic acid, and glutaric acid. Examples of the pine resin include activated pine resin and non-activated pine resin. The flux is preferably an organic acid having two or more carboxyl groups or pine resin. The above-mentioned flux may be an organic acid having two or more carboxyl groups, or may be pine resin. By using an organic acid or pine resin having two or more carboxyl groups, the reliability of conduction between the electrodes is further increased.

Examples of the organic acids having two or more carboxyl groups include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid.

Examples of the amine compounds include cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, imidazole, benzimidazole, phenylimidazole, carboxybenzimidazole, benzotriazole, and carboxybenzotriazole.

The above-mentioned pine resin is a rosin whose main component is abietic acid. Examples of the rosins include abietic acid and acrylic modified rosin. The flux is preferably a rosin, more preferably abietic acid. By using this preferable flux, the reliability of conduction between the electrodes is further increased.

The activation temperature (melting point) of the above flux is preferably 50°C or higher, more preferably 70°C or higher, even more preferably 80°C or higher, preferably 200°C or lower, more preferably 190°C or lower, even more preferably 160°C or lower. The temperature is preferably 150°C or lower, even more preferably 140°C or lower. When the activation temperature of the flux is above the above lower limit and below the above upper limit, the flux effect is even more effectively exhibited, and the solder can be disposed on the electrode even more efficiently.

The melting point of the flux can be determined by differential scanning calorimetry (DSC). Examples of the differential scanning calorimetry (DSC) device include "EXSTAR DSC7020" manufactured by SII.

Moreover, it is preferable that the boiling point of the above-mentioned flux is 200° C. or lower.

From the viewpoint of disposing the solder on the electrode more efficiently, the melting point of the flux is preferably higher than the reaction initiation temperature of the thermosetting agent, more preferably 5°C or more, more preferably 10°C or more. It is more preferable that it is high.

The flux may be dispersed in the conductive material or may be attached to the surface of the solder particles.

The above-mentioned flux is preferably a flux that releases cations when heated. By using a flux that releases cations when heated, the solder can be placed on the electrodes more efficiently.

Examples of the flux that releases cations upon heating include the thermal cation initiator (thermal cation curing agent).

From the viewpoint of arranging the solder more efficiently on the electrode, from the viewpoint of further effectively increasing the insulation reliability, and from the viewpoint of further effectively increasing the continuity reliability, the above-mentioned flux is composed of an acid compound and a basic compound. It is preferable that it is a salt with.

The acid compound is preferably an organic compound having a carboxyl group. The above acid compounds include aliphatic carboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, citric acid, malic acid, and cycloaliphatic carboxylic acids. Examples include cyclohexylcarboxylic acid, 1,4-cyclohexyldicarboxylic acid, aromatic carboxylic acids such as isophthalic acid, terephthalic acid, trimellitic acid, and ethylenediaminetetraacetic acid. From the viewpoint of arranging the solder more efficiently on the electrode, from the viewpoint of further effectively increasing the insulation reliability, and from the viewpoint of further effectively increasing the conduction reliability, the above acid compounds include glutaric acid, cyclohexyl Preferably, it is carboxylic acid or adipic acid.

The basic compound is preferably an organic compound having an amino group. The above basic compounds include diethanolamine, triethanolamine, methyldiethanolamine, ethyldiethanolamine, cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, 2-methylbenzylamine, 3-methylbenzylamine, 4-tert-butylbenzylamine. , N-methylbenzylamine, N-ethylbenzylamine, N-phenylbenzylamine, N-tert-butylbenzylamine, N-isopropylbenzylamine, N,N-dimethylbenzylamine, imidazole compounds, and triazole compounds. . From the viewpoint of arranging the solder on the electrode more efficiently, from the viewpoint of further effectively increasing insulation reliability, and from the viewpoint of further effectively increasing continuity reliability, the above basic compound is benzylamine. It is preferable.

The content of the flux in 100% by weight of the conductive material is preferably 0.5% by weight or more, preferably 30% by weight or less, and more preferably 25% by weight or less. When the content of the flux is above the above lower limit and below the above upper limit, it becomes even more difficult to form an oxide film on the surfaces of the solder and electrodes, and furthermore, the oxide film formed on the surfaces of the solder and electrodes becomes even more effective. can be removed.

(filler)
The above-mentioned conductive material may contain a filler. The filler may be an organic filler or an inorganic filler. When the conductive material contains a filler, the solder can be more uniformly aggregated over all the electrodes of the substrate. Further, since the conductive material contains a filler, the solder particles can be more uniformly dispersed in the conductive material.

It is preferable that the conductive material does not contain the filler or contains 5% by weight or less of the filler. When using the above-mentioned thermosetting compound, the smaller the filler content, the easier the solder particles will move onto the electrode.

The content of the filler in 100% by weight of the conductive material is preferably 0% by weight (not contained) or more, preferably 5% by weight or less, more preferably 2% by weight or less, even more preferably 1% by weight or less. It is. When the content of the filler is not less than the above lower limit and not more than the above upper limit, the solder is more uniformly arranged on the electrode.

(other ingredients)
The above-mentioned conductive material may contain, if necessary, a filler, an extender, a softener, a plasticizer, a thixotropic agent, a leveling agent, a polymerization catalyst, a curing catalyst, a coloring agent, an antioxidant, a heat stabilizer, and a light stabilizer. , an ultraviolet absorber, a lubricant, an antistatic agent, a flame retardant, and other various additives.

(Connected structure and method for manufacturing the connected structure)
The connection structure according to the present invention includes a first connection target member having a first electrode on its surface, a second connection target member having a second electrode on its surface, and the first connection target member, and a connecting portion connecting the second connection target member. In the connected structure according to the present invention, the material of the connecting portion is the conductive material described above. In the connected structure according to the present invention, the first electrode and the second electrode are electrically connected by a solder part in the connecting part.

A method for manufacturing a connected structure according to the present invention includes a step of using the above-mentioned conductive material and arranging the above-described conductive material on the surface of a first connection target member having a first electrode on the surface. The method for manufacturing a connected structure according to the present invention includes a method for manufacturing a connected structure, in which a second connection target member having a second electrode on the surface is placed on a surface of the conductive material opposite to the first connection target member side. The method includes a step of arranging the first electrode and the second electrode so as to face each other. The method for manufacturing a connected structure according to the present invention provides a connection between the first connection target member and the second connection target member by heating the conductive material above the melting point of the solder particles. forming the part from the conductive material, and electrically connecting the first electrode and the second electrode by a solder part in the connecting part.

In the bonded structure and the method for manufacturing the bonded structure according to the present invention, since a specific conductive material is used, solder particles tend to collect between the first electrode and the second electrode, and the solder is transferred to the electrode (line ) can be efficiently placed on top. In addition, a portion of the solder is less likely to be placed in the area (space) where no electrode is formed, and the amount of solder placed in the area where no electrode is formed can be considerably reduced. Therefore, the reliability of conduction between the first electrode and the second electrode can be improved. Moreover, electrical connection between horizontally adjacent electrodes that should not be connected can be prevented, and insulation reliability can be improved.

In addition, in order to more efficiently arrange the solder on the electrodes and considerably reduce the amount of solder placed in areas where no electrodes are formed, the above conductive material should be a conductive paste rather than a conductive film. It is preferable to use

The thickness of the solder portion between the electrodes is preferably 10 μm or more, more preferably 20 μm or more, and preferably 100 μm or less, more preferably 80 μm or less. The solder wetted area on the surface of the electrode (the area in contact with the solder out of 100% of the exposed area of the electrode) is preferably 50% or more, more preferably 70% or more, and preferably 100% or less.

In the method for manufacturing a connected structure according to the present invention, in the step of arranging the second connection target member and the step of forming the connection part, no pressure is applied to the conductive material, and the second connection target member is not pressurized. Preferably, the weight of the target member is added. In the method for manufacturing a connected structure according to the present invention, in the step of arranging the second member to be connected and the step of forming the connecting portion, the conductive material is subjected to the force of the weight of the second member to be connected. It is preferable not to apply pressure exceeding . In these cases, the uniformity of the amount of solder can be further improved in the plurality of solder parts. Furthermore, the thickness of the solder part can be increased even more effectively, making it easier for multiple solder particles to gather between the electrodes, making it possible to more efficiently arrange multiple solder particles on the electrodes (lines). can. Furthermore, some of the plurality of solder particles are less likely to be placed in areas (spaces) where electrodes are not formed, and the amount of solder placed in areas where electrodes are not formed can be further reduced. Therefore, the reliability of conduction between the electrodes can be further improved. Moreover, electrical connections between horizontally adjacent electrodes that should not be connected can be further prevented, and insulation reliability can be further improved.

Further, if a conductive paste is used instead of a conductive film, it becomes easy to adjust the thickness of the connection portion and the solder portion by adjusting the amount of conductive paste applied. On the other hand, with conductive films, there is a problem in that in order to change or adjust the thickness of the connection part, it is necessary to prepare conductive films of different thicknesses or to prepare conductive films of a predetermined thickness. There is. Further, in a conductive film, compared to a conductive paste, the melt viscosity of the conductive film cannot be sufficiently lowered at the melting temperature of the solder particles, and aggregation of the solder particles tends to be inhibited.

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

FIG. 1 is a cross-sectional view schematically showing a connected structure obtained using a conductive material according to an embodiment of the present invention.

The connection structure 1 shown in FIG. 1 includes a first connection target member 2, a second connection target member 3, and a connection connecting the first connection target member 2 and the second connection target member 3. 4. The connecting portion 4 is made of the above-mentioned conductive material. In this embodiment, the conductive material includes a thermosetting component, a plurality of solder particles, a gap material, and a flux. The gap material is a solder particle having a larger average particle diameter than the solder particle. The thermosetting component includes a thermosetting compound. In this embodiment, a conductive paste is used as the conductive material.

The connecting portion 4 includes a solder portion 4A in which a plurality of solder particles and gap materials are gathered and bonded to each other, and a cured material portion 4B in which a thermosetting compound is thermoset.

The first connection target member 2 has a plurality of first electrodes 2a on its surface (upper surface). The second connection target member 3 has a plurality of second electrodes 3a on the front surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by a solder portion 4A. Therefore, the first connection target member 2 and the second connection target member 3 are electrically connected by the solder portion 4A. Note that, in the connection portion 4, no solder exists in a region different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a (cured material portion 4B portion). In a region different from the solder portion 4A (cured material portion 4B portion), there is no solder separate from the solder portion 4A. Note that solder may be present in a region different from the solder portion 4A gathered between the first electrode 2a and the second electrode 3a (cured material portion 4B portion) as long as the amount is small. Note that it is preferable that the solder wets and spreads on the surface of the electrode, and the solder does not necessarily need to be gathered between the upper and lower electrodes.

As shown in FIG. 1, in the connection structure 1, a plurality of solder particles and gap materials gather between the first electrode 2a and the second electrode 3a, and after the plurality of solder particles and gap materials are melted, The solder portion 4A is formed by solidifying the melted solder particles and the gap material after spreading over the surface of the electrode. Therefore, the connection area between the solder portion 4A and the first electrode 2a and between the solder portion 4A and the second electrode 3a becomes large. That is, by using solder particles, the solder portion 4A and the first electrode 2a, as well as the solder portion 4A and the The contact area with the second electrode 3a becomes larger. This also increases the conduction reliability and connection reliability in the connection structure 1. Note that the flux contained in the conductive material is generally gradually deactivated by heating.

In addition, in the connection structure 1 shown in FIG. 1, all of the solder parts 4A are located in the opposing region between the first and second electrodes 2a and 3a. The modified connected structure 1X shown in FIG. 3 differs from the connected structure 1 shown in FIG. 1 only in the connecting portion 4X. The connecting portion 4X has a solder portion 4XA and a cured material portion 4XB. Like the connection structure 1X, most of the solder portion 4XA is located in the area where the first and second electrodes 2a and 3a are facing each other, and a part of the solder portion 4XA is located in the area where the first and second electrodes 2a and 3a face each other. It may protrude laterally from the opposing regions of the electrodes 2a and 3a. The solder portion 4XA that protrudes laterally from the opposing region of the first and second electrodes 2a and 3a is a part of the solder portion 4XA, and is not solder separate from the solder portion 4XA. In addition, in this embodiment, the amount of solder separated from the solder part can be reduced, but solder particles and gap material separated from the solder part may exist in the cured material part.

By reducing the amount of solder particles used, it becomes easier to obtain the connected structure 1. If the amount of solder particles used is increased, it becomes easier to obtain the connected structure 1X.

In the connection structures 1 and 1X, when looking at the opposing portions of the first electrode 2a and the second electrode 3a in the stacking direction of the first electrode 2a, the connection parts 4 and 4X, and the second electrode 3a Preferably, the solder portions 4A and 4XA in the connecting portions 4 and 4X are arranged in 50% or more of the 100% area of the opposing portions of the first electrode 2a and the second electrode 3a. . When the solder portions 4A and 4XA in the connection portions 4 and 4X satisfy the above-mentioned preferred embodiments, the continuity reliability can be further improved.

When looking at the opposing portions of the first electrode and the second electrode in the stacking direction of the first electrode, the connecting portion, and the second electrode, the first electrode and the second electrode It is preferable that the solder portion in the connection portion is disposed on 50% or more of the 100% area of the portion facing the second electrode. When looking at the opposing portions of the first electrode and the second electrode in the stacking direction of the first electrode, the connecting portion, and the second electrode, the first electrode and the second electrode It is more preferable that the solder portion in the connection portion is disposed on 60% or more of the 100% area of the portion facing the second electrode. When looking at the opposing portions of the first electrode and the second electrode in the stacking direction of the first electrode, the connecting portion, and the second electrode, the first electrode and the second electrode It is more preferable that the solder part in the connection part is disposed on 70% or more of the 100% area of the part facing the second electrode. When looking at the opposing portions of the first electrode and the second electrode in the stacking direction of the first electrode, the connecting portion, and the second electrode, the first electrode and the second electrode It is particularly preferable that the solder portion in the connection portion is disposed on 80% or more of the 100% area of the portion facing the second electrode. When looking at the opposing portions of the first electrode and the second electrode in the stacking direction of the first electrode, the connecting portion, and the second electrode, the first electrode and the second electrode It is most preferable that the solder part in the connection part is disposed on 90% or more of the 100% area of the part facing the second electrode. When the solder portion in the connection portion satisfies the preferred embodiments described above, conduction reliability can be further improved.

When the opposing portions of the first electrode and the second electrode are viewed in a direction perpendicular to the stacking direction of the first electrode, the connection portion, and the second electrode, the first It is preferable that 60% or more of the solder portion in the connection portion is disposed at the portion where the electrode and the second electrode face each other. When the opposing portions of the first electrode and the second electrode are viewed in a direction perpendicular to the stacking direction of the first electrode, the connection portion, and the second electrode, the first More preferably, 70% or more of the solder portion in the connection portion is disposed in a portion where the electrode and the second electrode face each other. When the opposing portions of the first electrode and the second electrode are viewed in a direction perpendicular to the stacking direction of the first electrode, the connection portion, and the second electrode, the first It is further preferable that 90% or more of the solder portion in the connection portion be disposed at a portion where the electrode and the second electrode face each other. When the opposing portions of the first electrode and the second electrode are viewed in a direction perpendicular to the stacking direction of the first electrode, the connection portion, and the second electrode, the first It is particularly preferable that 95% or more of the solder portion in the connection portion is disposed at the portion where the electrode and the second electrode face each other. When the opposing portions of the first electrode and the second electrode are viewed in a direction perpendicular to the stacking direction of the first electrode, the connection portion, and the second electrode, the first It is most preferable that 99% or more of the solder portion in the connecting portion is disposed at the portion where the electrode and the second electrode face each other. When the solder portion in the connection portion satisfies the preferred embodiments described above, conduction reliability can be further improved.

Next, in FIG. 2, an example of a method for manufacturing the connected structure 1 using a conductive material according to an embodiment of the present invention will be described.

First, a first connection target member 2 having a first electrode 2a on its surface (upper surface) is prepared. Next, as shown in FIG. 2A, a conductive material 11 containing a thermosetting component 11B, solder particles 11A, and a gap material 11C is placed on the surface of the first connection target member 2 ( (first step, first placement step). The conductive material 11 used includes a thermosetting compound as the thermosetting component 11B. In this embodiment, the conductive material 11 is a conductive paste.

A conductive material 11 is placed on the surface of the first connection target member 2 on which the first electrode 2a is provided. After the conductive material 11 is arranged, the solder particles 11A and the gap material 11C are arranged both on the first electrode 2a (line) and on the region (space) where the first electrode 2a is not formed. There is.

Methods for disposing the conductive material 11 include, but are not particularly limited to, application using a dispenser, screen printing, and ejection using an inkjet device.

Further, a second connection target member 3 having a second electrode 3a on its surface (lower surface) is prepared. Next, as shown in FIG. 2(b), in the conductive material 11 on the surface of the first connection target member 2, on the surface of the conductive material 11 opposite to the first connection target member 2 side, Arranging the second connection target member 3 (second step, second arrangement step). The second connection target member 3 is placed on the surface of the conductive material 11 from the second electrode 3a side. At this time, the first electrode 2a and the second electrode 3a are made to face each other.

In the second arrangement step, the gap between the first electrode 2a and the second electrode 3a is controlled by the gap material 11C. In the second arrangement step, the gap material 11C (per piece) is brought into contact with both the first electrode 2a and the second electrode 3a. The solder particles 11A are different from the gap material that controls the distance between the first electrode 2a and the second electrode 3a in the second arrangement step. In the second arrangement step, the solder particles 11A (per solder particle) are not brought into contact with both the first electrode 2a and the second electrode 3a.

The distance between the first electrode and the second electrode in the second arrangement step is preferably 10 μm or more, more preferably 50 μm or more, and preferably 500 μm or less, more preferably 300 μm or less. When the distance between the first electrode and the second electrode in the second arrangement step is not less than the lower limit and not more than the upper limit, the solder can be placed on the electrodes even more efficiently, Continuity reliability and insulation reliability can be further improved.

Next, the conductive material 11 is heated to a temperature higher than the melting point of the solder particles 11A (third step, connection step). Preferably, the conductive material 11 is heated to a temperature higher than the curing temperature of the thermosetting component 11B (thermosetting compound). During this heating, the solder particles 11A existing in the region where no electrode is formed gather between the first electrode 2a and the second electrode 3a (self-agglomeration effect). When a conductive paste is used instead of a conductive film, the solder particles 11A gather more effectively between the first electrode 2a and the second electrode 3a. Further, the solder particles 11A and the gap material 11C are melted and joined to each other. Further, the thermosetting component 11B is thermoset. As a result, as shown in FIG. 2(c), the connection portion 4 connecting the first connection target member 2 and the second connection target member 3 is formed of the conductive material 11. A connecting portion 4 is formed by the conductive material 11, a solder portion 4A is formed by joining a plurality of solder particles 11A and a gap material 11C, and a cured material portion 4B is formed by thermosetting the thermosetting component 11B. Ru. If the solder particles 11A move sufficiently, the solder particles 11A that are not located between the first electrode 2a and the second electrode 3a start moving, and then the first electrode 2a and the second electrode 11A start moving. It is not necessary to keep the temperature constant until the movement of the solder particles 11A between the solder particles 3a and the solder particles 11A is completed.

In the second step and the third step, it is preferable that no pressure is applied. In this case, the weight of the second connection target member 3 is applied to the conductive material 11 . Therefore, when forming the connection portion 4, the solder particles 11A gather more effectively between the first electrode 2a and the second electrode 3a. Note that if pressure is applied in at least one of the second step and the third step, the solder particles 11A tend to gather between the first electrode 2a and the second electrode 3a. are more likely to be inhibited.

In addition, in this embodiment, since no pressure is applied, the alignment between the first electrode 2a and the second electrode 3a is slightly deviated, and the first connection target member 2 and the second connection target Even when the members 3 are overlapped, the slight deviation can be corrected to connect the first electrode 2a and the second electrode 3a (self-alignment effect). This is because the molten solder that has self-agglomerated between the first electrode 2a and the second electrode 3a is mixed with the solder between the first electrode 2a and the second electrode 3a and other parts of the conductive material. This is because energy is more stable when the area in contact with the component is minimized, and a force acts to create an aligned connection structure that has the minimum area. At this time, it is desirable that the conductive material is not cured and that the viscosity of the components other than the solder particles of the conductive material is sufficiently low at that temperature and time.

In this way, the connected structure 1 shown in FIG. 1 is obtained. In addition, the said 2nd process and the said 3rd process may be performed continuously. Further, after performing the second step, the obtained laminate of the first connection target member 2, the conductive material 11, and the second connection target member 3 is moved to a heating section, and the third You may perform the process. In order to perform the heating, the laminate may be placed on a heating member, or the laminate may be placed in a heated space.

The heating temperature in the third step is preferably 230°C or higher, more preferably 250°C or higher, and preferably 450°C or lower, more preferably 350°C or lower, and still more preferably 300°C or lower.

The heating method in the third step includes a method of heating the entire connected structure using a reflow oven or an oven above the melting point of the solder and the curing temperature of the thermosetting component; An example of this method is to locally heat only the connecting portion.

Examples of devices used in the local heating method include a hot plate, a heat gun that applies hot air, a soldering iron, and an infrared heater.

In addition, when heating locally with a hot plate, use a highly thermally conductive metal directly below the connection, and use a low thermally conductive material such as fluororesin for other areas where it is not desirable to heat. , preferably forming the top surface of the hot plate.

The first and second connection target members are not particularly limited. Specifically, the first and second connection target members include semiconductor chips, semiconductor packages, LED chips, LED packages, electronic components such as capacitors and diodes, resin films, printed circuit boards, flexible printed circuit boards, and flexible Examples include electronic components such as flat cables, rigid-flexible boards, circuit boards such as glass epoxy boards, and glass boards. It is preferable that the first and second connection target members are electronic components.

It is preferable that at least one of the first connection target member and the second connection target member is a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible circuit board. Resin films, flexible printed circuit boards, flexible flat cables, and rigid-flexible circuit boards have the properties of being highly flexible and relatively lightweight. When a conductive film is used to connect such connection target members, solder particles tend to be difficult to collect on the electrodes. On the other hand, by using a conductive paste, even if a resin film, flexible printed circuit board, flexible flat cable, or rigid-flex board is used, the solder particles can be efficiently collected on the electrodes, ensuring continuity between the electrodes. You can fully enhance your sexuality. When using resin films, flexible printed circuit boards, flexible flat cables, or rigid-flex circuit boards, the reliability of conduction between electrodes can be improved by not applying pressure, compared to when using other connection objects such as semiconductor chips. The improvement effect can be obtained even more effectively.

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

In the connected structure according to the present invention, it is preferable that the first electrode and the second electrode are arranged in an area array or a peripheral. When the first electrode and the second electrode are arranged in an area array or peripheral, the solder can be more effectively aggregated on the electrodes. The above-mentioned area array is a structure in which electrodes are arranged in a grid pattern on the surface of the connection target member on which the electrodes are arranged. The above-mentioned peripheral refers to a structure in which electrodes are arranged on the outer periphery of a member to be connected. In the case of a structure in which the electrodes are arranged in a comb shape, the solder only needs to agglomerate along the direction perpendicular to the comb, whereas in the above area array or peripheral structure, the solder aggregates over the entire surface on the surface where the electrodes are arranged. It is necessary for the solder to coagulate uniformly. Therefore, in the conventional method, the amount of solder tends to be uneven, whereas in the method of the present invention, the solder can be uniformly aggregated over the entire surface.

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

Thermosetting component (thermosetting compound):
Thermosetting compound 1: Bisphenol F type epoxy compound, "YDF-8170C" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.
Thermosetting compound 2: Bisphenol A type epoxy compound, "YD-8125" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.
Thermosetting compound 3: Phenol novolac type epoxy compound, “DEN431” manufactured by DOW
Thermosetting compound 4: Aliphatic epoxy compound, "Epolite 1600" manufactured by Kyoeisha Chemical Co., Ltd.
Thermosetting compound 5: Alicyclic epoxy compound, "THI-DE" manufactured by JXTG Energy Corporation

Solder particles:
Solder particle 1: Sn-3Ag-0.5Cu, average particle size: 20 μm, melting point 214°C

flux:
Flux 1: “Glutaric acid benzylamine salt”, melting point 108°C
How to make Flux 1:
24 g of water as a reaction solvent and 13.212 g of glutaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a glass bottle and dissolved until uniform at room temperature. Then, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a mixed solution. The resulting mixture was placed in a refrigerator at 5 to 10°C and left overnight. The precipitated crystals were collected by filtration, washed with water, and vacuum dried to obtain Flux 1.

Gap material:
Gap material 1: Divinylbenzene copolymer resin particles, “AU-275” manufactured by Sekisui Chemical Co., Ltd., average particle size: 75 μm
Gap material 2: Divinylbenzene copolymer resin particles, “AU-250” manufactured by Sekisui Chemical Co., Ltd., average particle size: 50 μm
Gap material 3: Divinylbenzene copolymer resin particles, “AU-230” manufactured by Sekisui Chemical Co., Ltd., average particle size: 30 μm

The average particle diameters of the solder particles and gap material were measured using a laser diffraction particle size distribution analyzer (“LA-920” manufactured by Horiba, Ltd.).

(Examples 1 to 10 and Comparative Example 1)
(1) Preparation of conductive material (anisotropic conductive paste) The components shown in Table 1 below were blended in the amounts shown in Table 1 below to obtain a conductive material (anisotropic conductive paste).

(2) Preparation of connection structure As the first connection target member, a glass epoxy substrate (FR -4 substrate, thickness 0.6 mm) was prepared.

As the second connection target member, a flexible printed circuit board (made of polyimide, thickness 0.1 mm) has a copper electrode pattern (L/S: 50 μm/50 μm, electrode length: 3 mm, electrode thickness: 12 μm) on the lower surface. prepared.

On the upper surface of the glass epoxy substrate, a conductive material (anisotropic conductive paste) immediately after preparation was printed to a thickness of 100 μm by screen printing to form a conductive material (anisotropic conductive paste) layer. Next, a flexible printed circuit board was laminated on the upper surface of the conductive material (anisotropic conductive paste) layer so that the electrodes faced each other. The weight of the flexible printed circuit board is added to the conductive material (anisotropic conductive paste) layer. From this state, the conductive material (anisotropic conductive paste) layer was heated so that the temperature reached the melting point of the solder particles 5 seconds after the start of temperature rise. Furthermore, 15 seconds after the start of temperature rise, the conductive material (anisotropic conductive paste) layer is heated to a temperature of 240°C to harden the conductive material (anisotropic conductive paste) layer, and the connected structure is formed. Obtained. No pressure was applied during heating.

(evaluation)
(1) Accuracy of solder placement on electrodes (wetted area ratio)
In the obtained connection structure, when looking at the portion where the first electrode and the second electrode face each other in the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode are opposite to each other. The ratio X of the area where the solder part in the connection part is arranged to 100% of the area of the part facing the second electrode was evaluated. The placement accuracy of the solder on the electrode was judged based on the following criteria. Note that the larger the ratio X is, the more voids in the solder portion are suppressed.

[Criteria for determining accuracy of solder placement on electrodes]
○○: Proportion X is 90% or more ○: Proportion X is 75% or more and less than 90% ×: Proportion X is less than 75%

Details and results are shown in Table 1 below.

Similar trends were observed even when flexible printed circuit boards, resin films, flexible flat cables, and rigid-flex circuit boards were used.

1, 1X... Connection structure 2... First connection target member 2a... First electrode 3... Second connection target member 3a... Second electrode 4, 4X... Connection part 4A, 4XA... Solder part 4B, 4XB ...Cured product part 11...Conductive material 11A...Solder particles 11B...Thermosetting component 11C...Gap material

Claims (9)

A conductive material containing a thermosetting compound, a plurality of solder particles , and a gap material ,
The thermosetting compound includes an aliphatic epoxy compound or an alicyclic epoxy compound,
In 100% by weight of the thermosetting compound, the total content of the aliphatic epoxy compound and the alicyclic epoxy compound is 0.5% by weight or more and 25% by weight or less,
The melting point of the solder particles is 150°C or more and 450°C or less,
A conductive material , wherein the gap material has an average diameter of 30 μm or more and 100 μm or less . The conductive material according to claim 1, wherein the solder particles have a melting point of 180°C or more and 350°C or less. The conductive material according to claim 1 or 2, which does not contain a thermosetting agent. the solder particles contain tin;
The conductive material according to any one of claims 1 to 3, wherein the content of tin is 40% by weight or more and 99.9% by weight or less in 100% by weight of metal contained in the solder particles. The conductive material according to any one of claims 1 to 4, wherein the thermosetting compound contains an aromatic epoxy compound. The conductive material according to claim 5, wherein the content of the aromatic epoxy compound is 75% by weight or more and 99.5% by weight or less in 100% by weight of the thermosetting compound. The conductive material according to any one of claims 1 to 6 , which is a conductive paste. a first connection target member having a first electrode on its surface;
a second connection target member having a second electrode on its surface;
comprising a connection part connecting the first connection target member and the second connection target member,
The material of the connecting portion is the conductive material according to any one of claims 1 to 7 ,
A connection structure in which the first electrode and the second electrode are electrically connected by a solder part in the connection part. using the conductive material according to any one of claims 1 to 7 , disposing the conductive material on the surface of the first connection target member having the first electrode on the surface;
A second connection target member having a second electrode on its surface is placed on a surface of the conductive material opposite to the first connection target member side, and the first electrode and the second electrode are opposite to each other. a step of arranging the
A connecting portion connecting the first connection target member and the second connection target member is formed from the conductive material by heating the conductive material to a temperature higher than the melting point of the solder particles, and A method for manufacturing a connected structure, comprising the step of electrically connecting the first electrode and the second electrode with a solder part in the connecting part.

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