TWI793307B - Conductive material, connection structure and method for manufacturing connection structure - Google Patents

Abstract

The present invention provides a conductive material, which can effectively improve the conduction reliability between the upper and lower electrodes to be connected even when the conductive material is heated by high-temperature reflow. The conductive material of the present invention includes a thermosetting component and a plurality of solder particles, the solder particles include tin, silver, and copper, the thermosetting component includes a thermosetting compound, and in 100% by weight of the conductive material, the thermosetting The content of the compound is 10% by weight or more.

Description

Conductive material, connection structure and method for manufacturing connection structure

The present invention relates to a conductive material comprising thermosetting components and solder particles. Also, the present invention relates to a connection structure using the above-mentioned conductive material and a method for manufacturing the connection structure.

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

The aforementioned anisotropic conductive materials are used to obtain various connection structures. As the connection using the above-mentioned anisotropic conductive material, for example, the connection between a flexible printed substrate and a glass substrate (FOG (Film on Glass, coated glass)), the connection between a semiconductor chip and a flexible printed substrate (COF (Chip on Film) , film-on-chip)), the connection of semiconductor chips and glass substrates (COG (Chip on Glass, glass-on-glass)), and the connection of flexible printed substrates and glass epoxy substrates (FOB (Film on Board, coated board)), etc. .

Using the above-mentioned anisotropic conductive material, for example, when the electrodes of the flexible printed circuit board and the electrodes of the glass epoxy substrate are electrically connected, the anisotropic conductive material including conductive particles is arranged on the glass epoxy substrate. Next, the flexible printed circuit board is laminated and heated and pressed. Thereby, the anisotropic conductive material is hardened, and between electrodes are electrically connected via electroconductive particle, and the connection structure is obtained.

As an example of the said anisotropic electrically-conductive material, the following patent document 1 discloses the electrically-conductive paste containing a binder resin and electroconductive particle. The above-mentioned binder resin contains a thermal radical polymerizable compound and a thermal radical polymerization initiator. The storage modulus at 90°C of the above-mentioned binder resin is 8 Pa or more and less than 500 MPa, or the storage modulus at 90°C of the above-mentioned conductive paste is 8 Pa or more and less than 500 MPa. It is described in the following patent document 1 that solder particles are used as electroconductive particles. Patent Document 1 below describes the use of SnBi solder particles as the solder particles. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-005502

[Problem to be solved by the invention]

When the conductive material containing solder particles is used for conductive connection, the plurality of upper electrodes are electrically connected with the lower plurality of electrodes to perform conductive connection. The solder is preferably arranged between the upper and lower electrodes to be connected, and it is more preferable not to be arranged between adjacent horizontal electrodes. Ideally, the adjacent lateral electrodes are not electrically connected.

Generally, a conductive material including solder particles is used after being placed on a substrate and then heated by reflow or the like. By heating the conductive material above the melting point of the solder particles, the solder particles are melted, and the solder aggregates between the electrodes, whereby a solder portion is formed between the electrodes, and the upper and lower electrodes to be connected are electrically connected by the solder portion. connect.

In conventional conductive materials, solder particles with a relatively low melting point may be used, and if heated by high-temperature reflow (for example, repeated 5 times of reflow at 260°C), the solder part may be heated and deteriorate. If the solder part deteriorates, the conduction reliability between the upper and lower electrodes to be connected may decrease, and the yield may decrease. Conventional conductive materials cannot sufficiently improve conduction reliability between electrodes after high-temperature reflow.

The object of the present invention is to provide a conductive material, which can effectively improve the conduction reliability between the upper and lower electrodes to be connected even when the conductive material is heated by high-temperature reflow. Moreover, the object of this invention is to provide the manufacturing method of the connection structure using the said electrically-conductive material, and a connection structure. [Technical means to solve the problem]

According to a broad aspect of the present invention, there is provided a conductive material comprising a thermosetting component and a plurality of solder particles, the solder particles comprising tin, silver, and copper, the thermosetting component comprising a thermosetting compound, and conducting The content of the above-mentioned thermosetting compound is 10% by weight or more in 100% by weight of the material.

In a specific aspect of the conductive material of the present invention, the average particle diameter of the above-mentioned solder particles is 10 μm or less.

In a specific aspect of the conductive material of the present invention, the viscosity of the conductive material at 25° C. and 5 rpm immediately after thawing the frozen-stored conductive material is 100 Pa·s or more.

In a specific aspect of the conductive material of the present invention, the viscosity of the conductive material at 25° C. and 0.5 rpm after thawing the above-mentioned conductive material that has been frozen and stored is divided by the viscosity of the conductive material that has just been thawed and stored frozen. The thixotropic index obtained from the viscosity of the conductive material at 25°C and 5 rpm is 2 or more.

In a specific aspect of the conductive material of the present invention, the viscosity of the conductive material at 25°C and 5 rpm after storing the above-mentioned conductive material just after production under the conditions of 25°C and 24 hours is relative to that immediately after production The ratio of the viscosities of the above conductive materials at 25°C and 5 rpm is 1.2 or less.

In a specific aspect of the conductive material of the present invention, the viscosity of the conductive material at 25°C and 5 rpm after thawing the above-mentioned conductive material that has been refrigerated is compared to the viscosity of the above-mentioned conductive material just after production at 25°C and The viscosity ratio at 5 rpm is 1.2 or less.

In a specific aspect of the conductive material of the present invention, it is used for the mounting of electronic components whose electrodes have a planar area of 70×10 ³ μm ² or less.

In a specific aspect of the conductive material of the present invention, the above-mentioned electronic components are semiconductor chips, semiconductor packages, LED (Light Emitting Diode, light emitting diode) chips, LED packages, capacitors, or diodes.

In a specific aspect of the conductive material of the present invention, the above-mentioned conductive material is a conductive paste.

According to a broad aspect of the present invention, there is provided a connection structure comprising: a first connection object member having a first electrode on its surface; a second connection object member having a second electrode on its surface; and a connection portion, It connects the above-mentioned first connection object member and the above-mentioned second connection object member; the material of the above-mentioned connection part is the above-mentioned conductive material; and the above-mentioned first electrode and the above-mentioned second electrode are electrically connected by the solder part in the above-mentioned connection part .

In a specific aspect of the connection structure of the present invention, when the portion where the first electrode and the second electrode face each other is viewed in the lamination direction of the first electrode, the connection portion, and the second electrode The solder portion in the connection portion is disposed on at least 50% of 100% of the area of the portion where the first electrode and the second electrode face each other.

According to a broad aspect of the present invention, there is provided a method of manufacturing a connection structure, which includes the following steps: using the above-mentioned conductive material, disposing the above-mentioned conductive material on the surface of the first connection object member having the first electrode on the surface; On the surface of the conductive material opposite to the side of the first connection object member, a second connection object member having a second electrode on the surface is arranged in such a manner that the first electrode and the second electrode face each other; The material is heated above the melting point of the solder particles, and the connection part connecting the first connection object member and the second connection object member is formed by the above-mentioned conductive material, and the above-mentioned first electrode is connected by the solder part in the connection part. It is electrically connected with the above-mentioned second electrode.

In a specific aspect of the method for manufacturing a connection structure of the present invention, a connection structure is obtained in which the first electrode, the connection portion, and the second electrode are stacked in the layered direction. In the case where the 1st electrode and the 2nd electrode face each other, the solder portion of the connecting portion is arranged on 50% or more of the 100% area of the portion where the 1st electrode and the 2nd electrode face each other. [Effect of Invention]

The conductive material of the present invention includes a thermosetting component and a plurality of solder particles. In the conductive material of the present invention, the solder particles include tin, silver, and copper. In the conductive material of the present invention, the thermosetting component includes a thermosetting compound. In the conductive material of the present invention, the content of the thermosetting compound is 10% by weight or more in 100% by weight of the conductive material. In the conductive material of the present invention, due to the above configuration, even when the conductive material is heated by high-temperature reflow, the conduction reliability between the upper and lower electrodes to be connected can be effectively improved.

Hereinafter, the details of the present invention will be described.

(conductive material) The conductive material of the present invention includes a thermosetting component and a plurality of solder particles. In the conductive material of the present invention, the solder particles include tin, silver, and copper. In the conductive material of the present invention, the thermosetting component includes a thermosetting compound. In the conductive material of the present invention, the content of the thermosetting compound is 10% by weight or more in 100% by weight of the conductive material.

In the conductive material of the present invention, due to the above configuration, even when the conductive material is heated by high-temperature reflow, the conduction reliability between the upper and lower electrodes to be connected can be effectively improved.

The conductive material including solder particles is used after being placed on the substrate and then heated by reflow or the like. By heating the conductive material above the melting point of the solder particles, the solder particles melt and the solder aggregates between the electrodes, whereby a solder portion is formed between the electrodes, and the upper and lower electrodes to be connected are electrically connected by the solder portion .

In conventional conductive materials, solder particles with a relatively low melting point may be used. If heating is performed by high-temperature reflow (for example, repeated 5 times of reflow at 260°C), the above-mentioned solder part may deteriorate due to heat. situation. If the above-mentioned solder portion deteriorates, the conduction reliability between the upper and lower electrodes to be connected may decrease, and the yield may decrease.

The inventors of the present invention have found that by using specific solder particles (solder particles with a relatively high melting point), even when heating is performed by high-temperature reflow, it is possible to prevent the above-mentioned deterioration of the solder portion due to heat . In the present invention, even in the case of heating by high-temperature reflow, it is possible to effectively improve the conduction reliability between the upper and lower electrodes to be connected.

In the present invention, in order to obtain the above effects, it is very helpful for the above-mentioned conductive material to include specific solder particles.

Also, in the present invention, different from the conventional conductive material, specific solder particles (solder particles with a relatively high melting point) are used. In conventional conductive materials, if solder particles with a relatively high melting point are used, the thermosetting component may harden before the solder particles are melted at the time of conductive connection. If the thermosetting component is hardened before the solder particles are melted, the solder particles may not aggregate between the electrodes during conductive connection, and the electrodes may not be electrically connected. The inventors of the present invention have found that even if specific solder particles (solder particles with a relatively high melting point) are used, by controlling the average particle size of the solder particles, the viscosity of the conductive material, the thixotropy of the conductive material, and the hardening speed of the hardening component etc., the solder particles can be aggregated between the electrodes, and the electrodes can be electrically connected. In the present invention, even if solder particles with a relatively high melting point are used, the solder particles can be aggregated between electrodes, and the electrodes can be electrically connected.

In the present invention, in order to obtain the above-mentioned effects, in addition to the above-mentioned conductive material containing specific solder particles, the average particle size of the solder particles, the viscosity of the conductive material, the thixotropy of the conductive material, and the hardening speed of the hardening component are controlled. Etc. is also of great help.

In addition, in the present invention, since the above-mentioned structure is provided, when electrically connecting the electrodes, the solder tends to gather between the upper and lower facing electrodes, and the solder can be arranged on the electrodes (lines). In addition, part of the solder is not easily arranged between the horizontal electrodes that should not be connected, so that the amount of solder that is arranged between the horizontal electrodes that should not be connected can be considerably reduced. As a result, in the present invention, the residual amount of solder can be reduced between the horizontal electrodes that should not be connected.

Furthermore, in the present invention, positional displacement between electrodes can be prevented. In the present invention, when the second connection object member is overlapped with the first connection object member on which the conductive material is arranged on the upper surface, even if the alignment deviation between the electrodes of the first connection object member and the electrodes of the second connection object member In this state, the offset can also be corrected so that the electrodes are connected to each other (self-alignment effect).

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

The viscosity (η25) of the above-mentioned conductive material immediately after production at 25°C and 5 rpm is preferably at least 100 Pa·s, more preferably at least 120 Pa·s, preferably at most 200 Pa·s, more preferably 180 Below Pa・s. If the above-mentioned viscosity (η25) is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, and the conduction reliability between the upper and lower electrodes to be connected can be further effectively improved. The above-mentioned viscosity (η25) can be adjusted appropriately according to the type and amount of compounded ingredients.

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

The viscosity (ηA) of the conductive material at 25°C and 5 rpm after thawing and storing the above-mentioned conductive material is preferably at least 100 Pa·s, more preferably at least 120 Pa·s, more preferably 200 Pa·s Below, more preferably below 180 Pa·s. If the above-mentioned viscosity (ηA) is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, and the conduction reliability between the upper and lower electrodes to be connected can be further effectively improved. The above-mentioned viscosity (ηA) can be appropriately adjusted according to the type and amount of the compounded ingredients.

Furthermore, in the present invention, the viscosity (ηA) of the conductive material at 25°C and 5 rpm immediately after thawing the above-mentioned conductive material stored in a freezer means the viscosity (ηA) of the conductive material stored in a freezer at 25°C for 2 hours. Viscosity of conductive material at 25°C and 5 rpm.

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

In addition, in this specification, the condition of the frozen storage of the conductive material used for measuring the viscosity is the condition of storage at -20 degreeC for 7 days. On the other hand, the conditions for the above-mentioned frozen storage during actual use of the conductive material are not particularly limited. The temperature of the above-mentioned refrigerated storage is not particularly limited, as long as it does not reach 0°C. The temperature of the above-mentioned frozen storage may be -10°C or lower, -20°C or lower, or -40°C or lower. The period of the frozen storage is not particularly limited as long as it is 360 days or less. The above-mentioned frozen storage period may be longer than 30 days, may be longer than 60 days, may be longer than 90 days, or may be longer than 180 days.

In addition, in this specification, the thawing condition of the conductive material used for measuring the viscosity is the condition of storing at 25° C. for 2 hours. On the other hand, there is no particular limitation on the method of thawing the above-mentioned conductive material that has been frozen and stored during actual use of the conductive material. As a method of thawing the above-mentioned conductive material stored in a freezer, a method of thawing at room temperature, a method of thawing under refrigerated conditions, and a method of thawing under heating conditions, etc. may be mentioned. The aforementioned room temperature conditions are preferably not less than 20°C and not more than 25°C. It is preferable that the said refrigeration conditions are more than 0 degreeC and 10 degreeC or less. The above-mentioned heating conditions are preferably not less than 30°C and not more than 35°C.

The ratio (ηA) of the viscosity (ηA) of the conductive material at 25°C and 5 rpm to the viscosity (η25) of the conductive material at 25°C and 5 rpm immediately after thawing and storage of the above-mentioned conductive material (ηA /η25) is preferably 1.2 or less, more preferably 1.1 or less. The lower limit of the ratio (ηA/η25) is not particularly limited. The above ratio (ηA/η25) may be 1 or more. If the above-mentioned ratio (ηA/η25) is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, and the conduction reliability between the upper and lower electrodes to be connected can be further effectively improved.

The viscosity (ηB) of the conductive material at 25°C and 0.5 rpm after thawing the above-mentioned conductive material stored in a freezer is preferably 250 Pa·s or higher, more preferably 300 Pa·s or higher, more preferably 800 Pa·s Below, more preferably below 600 Pa·s. If the above-mentioned viscosity (ηB) is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, and the conduction reliability between the upper and lower electrodes to be connected can be further effectively improved. The above-mentioned viscosity (ηB) can be appropriately adjusted according to the type and amount of the compounded ingredients.

Furthermore, in the present invention, the viscosity (ηB) of the conductive material at 25° C. and 0.5 rpm immediately after thawing the above-mentioned conductive material stored by freezing means the viscosity (ηB) of the conductive material stored by freezing at 25° C. for 2 hours. Viscosity of conductive material at 25°C and 0.5 rpm.

The aforementioned viscosity (ηB) can be measured, for example, using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) at 25°C and 0.5 rpm.

The viscosity (ηB) of the conductive material at 25°C and 0.5 rpm after thawing the above-mentioned conductive material that has been frozen and stored is divided by the viscosity of the conductive material at 25°C and 5 rpm after thawing the above conductive material that has been stored frozen ηA) The thixotropic index (ηB/ηA) obtained is preferably 2 or more, more preferably 3 or more. The above-mentioned thixotropic index (ηB/ηA) is preferably 5 or less, more preferably 4 or less. If the above-mentioned thixotropic index (ηB/ηA) is more than the above-mentioned lower limit and below the above-mentioned upper limit, then the solder can be more efficiently arranged on the electrodes, and the conduction reliability between the upper and lower electrodes to be connected can be further effectively improved.

The viscosity (ηC) of the conductive material at 25°C and 5 rpm after storing the above-mentioned conductive material immediately after production under the conditions of 25°C and 24 hours is preferably 100 Pa·s or higher, more preferably 120 Pa·s or higher , preferably below 200 Pa·s, more preferably below 180 Pa·s. If the above-mentioned viscosity (ηC) is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, and the conduction reliability between the upper and lower electrodes to be connected can be further effectively improved. The above-mentioned viscosity (ηC) can be appropriately adjusted according to the type and amount of the compounded ingredients.

The aforementioned viscosity (ηC) can be measured, for example, using an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) at 25°C and 5 rpm.

The viscosity (ηC) of the conductive material at 25°C and 5 rpm after storing the above-mentioned conductive material just after production under the conditions of 25°C and 24 hours is relative to the viscosity (ηC) of the above-mentioned conductive material immediately after production at 25°C and 5 rpm The viscosity (η25) ratio (ηC/η25) is preferably 1.2 or less, more preferably 1.1 or less. The lower limit of the ratio (ηC/η25) is not particularly limited. The above ratio (ηC/η25) may be 1 or more. If the above-mentioned ratio (ηC/η25) is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, and the conduction reliability between the upper and lower electrodes to be connected can be further effectively improved.

The viscosity (ηmp) of the conductive material at the melting point of the solder particles is preferably at most 50 a·s, more preferably at most 30 Pa·s, further preferably at most 10 Pa·s, more preferably at least 0.5 Pa·s, More preferably, it is 1 Pa·s or more. If the said viscosity (ηmp) is below the said upper limit, solder can be efficiently aggregated on an electrode. When the said viscosity is more than the said minimum, the void in a connection part can be suppressed, and the exposure of a conductive material to the outside of a connection part can be suppressed.

The above-mentioned viscosity (ηmp) can be measured using STRESSTECH (manufactured by REOLOGICA Co., Ltd.) at a strain control of 1 rad, a frequency of 1 Hz, a heating rate of 20°C/min, and a measurement temperature range of 25°C to 200°C (where the melting point of solder particles exceeds 200 In the case of °C, the upper limit of the temperature is defined as the melting point of the solder particles). Calculate the viscosity of the conductive material at the melting point of the solder particles from the measurement results.

The above-mentioned conductive material can be used as a conductive paste, a conductive film, and the like. The above-mentioned conductive paste is preferably an anisotropic conductive paste, and the above-mentioned conductive film is preferably an anisotropic conductive film. From the viewpoint of disposing the solder on the electrodes more efficiently, the above-mentioned conductive material is preferably a conductive paste. The above-mentioned conductive material is preferably used for electrical connection of electrodes. The above-mentioned conductive material is preferably a circuit connection material.

The above-mentioned conductive material is preferably used for mounting electronic parts. The above-mentioned conductive material is preferably used for mounting electronic components whose electrodes have a planar area of 70×10 ³ μm ² or less, more preferably used for mounting electronic components whose electrodes have a planar area of 65×10 ³ μm ² or less. The planar area of the electrodes of the above-mentioned electronic components is preferably at most 3×10 ³ μm ² , more preferably at most 2×10 ³ μm ² . The aforementioned electronic components are preferably semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors, or diodes, more preferably LED chips or LED packages. The planar area of the electrode is the area when looking down on the surface to which the electrode is connected. The above-mentioned conductive material is preferably arranged on an electrode with a planar area of 3×10 ³ μm ² or less, more preferably arranged on an electrode with a planar area of 2×10 ³ μm ² or less.

Hereinafter, each component contained in the said conductive material is demonstrated. In addition, in this specification, "(meth)acryl" means one or both of "acryl" and "methacryl".

(solder particles) The conductive material of the present invention includes a plurality of solder particles. In the above-mentioned solder particles, both the central part and the outer surface are formed of solder. The above-mentioned solder particles are particles in which both the central part and the outer surface are solder. When the conductive particle provided with the base particle which consists of materials other than solder and the solder part arrange|positioned on the surface of this base particle is used instead of the said solder particle, it becomes difficult for conductive particle to gather on an electrode. In addition, in the above-mentioned conductive particles, the weldability of the conductive particles is low, so the conductive particles that have moved to the electrodes tend to move out of the electrodes, and the effect of suppressing the positional displacement between the electrodes is also reduced. tendency.

The aforementioned solder is preferably a metal having a melting point of 450° C. or lower (low melting point metal). The above-mentioned solder particles are preferably metal particles having a melting point of 450° C. or lower (low melting point metal particles). The above-mentioned 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 metal is preferably not higher than 300°C, more preferably not higher than 250°C. The above-mentioned solder particles preferably have a melting point of 450°C or lower, more preferably have a melting point of 300°C or lower, and still more preferably have a melting point of 250°C or lower.

The melting point of the above-mentioned solder particles can be determined by differential scanning calorimetry (DSC). As a differential scanning calorimetry (DSC) apparatus, "EXSTAR DSC7020" by SII company etc. are mentioned.

The above-mentioned solder particles contain tin, silver, and copper. The above-mentioned solder particles may also contain metals other than tin, silver, and copper.

In 100% by weight of the metal contained in the solder particles, the tin content is preferably at least 96% by weight, more preferably at least 96.3% by weight, preferably at most 99% by weight, more preferably at most 98.8% by weight. If the content of tin in the above-mentioned solder particles is more than the above-mentioned lower limit and not more than the above-mentioned upper limit, the solder can be more efficiently arranged on the electrode, and even when the conductive material is heated by high-temperature reflow, it can be effective. The conduction reliability between the upper and lower electrodes to be connected can be greatly improved, and the connection reliability between the solder part and the electrodes can be further improved.

The silver content is preferably at least 0.9% by weight, more preferably at least 1.1% by weight, preferably at most 4% by weight, and more preferably at most 3.7% by weight, in 100% by weight of the metal contained in the solder particles. If the content of silver in the above-mentioned solder particles is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrode, and even when the conductive material is heated by high-temperature reflow, it can be effective. The conduction reliability between the upper and lower electrodes to be connected can be greatly improved, and the connection reliability between the solder part and the electrodes can be further improved.

The copper content is preferably at least 0.03% by weight, more preferably at least 0.1% by weight, preferably at most 0.5% by weight, and more preferably at most 0.4% by weight, in 100% by weight of the metal contained in the solder particles. If the content of copper in the above-mentioned solder particles is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrode, and even when the conductive material is heated by high-temperature reflow, it can be effective. The conduction reliability between the upper and lower electrodes to be connected can be greatly improved, and the connection reliability between the solder part and the electrodes can be further improved.

The total content of tin, silver, and copper is preferably at least 95% by weight, more preferably at least 98% by weight, in 100% by weight of the metal contained in the solder particles. If the total content of tin, silver, and copper in the above-mentioned solder particles is more than the above-mentioned lower limit, the solder can be more efficiently arranged on the electrode, even when the conductive material is heated by high-temperature reflow, It can also effectively improve the conduction reliability between the upper and lower electrodes to be connected, and can further improve the connection reliability between the solder part and the electrodes.

The ratio of the content of silver in 100% by weight of the metal contained in the above-mentioned solder particles to the content of tin in 100% by weight of the metal contained in the above-mentioned solder particles (content of silver/content of tin) is preferably 0.009 or more, more preferably It is preferably at least 0.011, more preferably at most 0.04, more preferably at most 0.036. If the above-mentioned ratio (silver content/tin content) is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrode, even when the conductive material is heated by high-temperature reflow, It can also effectively improve the conduction reliability between the upper and lower electrodes to be connected, and can further improve the connection reliability between the solder part and the electrodes.

The ratio of the content of copper in 100% by weight of the metal contained in the above-mentioned solder particles to the content of tin in 100% by weight of the metal contained in the above-mentioned solder particles (content of copper/content of tin) is preferably 0.0003 or more, more preferably It is preferably at least 0.0005, more preferably at most 0.004, more preferably at most 0.0035. If the above-mentioned ratio (copper content/tin content) is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrode, even when the conductive material is heated by high-temperature reflow, It can also effectively improve the conduction reliability between the upper and lower electrodes to be connected, and can further improve the connection reliability between the solder part and the electrodes.

Furthermore, the content of tin, silver, or copper contained in the above-mentioned solder particles can be determined using a high-frequency inductively coupled plasma emission spectrometer ("ICP-AES" manufactured by Horiba Manufacturing Co., Ltd.), or a fluorescent X-ray analyzer ( "EDX-800HS" manufactured by Shimadzu Corporation) and the like were measured.

By using the above-mentioned solder particles, the solder is melted and joined to the electrodes, and the solder portion provides electrical conduction between the electrodes. For example, since the solder portion and the electrode tend to be in surface contact rather than point contact, the connection resistance is reduced. In addition, the use of the above-mentioned solder particles improves the joint strength between the solder portion and the electrode, and as a result, peeling between the solder portion and the electrode is less likely to occur, and conduction reliability and connection reliability are further improved.

The above-mentioned solder particles may also contain low-melting point metals. The aforementioned low melting point metal is not particularly limited. The above-mentioned low-melting-point metal preferably contains tin or an alloy of tin. Examples of such alloys include tin-silver alloys, tin-copper alloys, tin-silver-copper alloys, tin-bismuth alloys, tin-lead alloys, and tin-indium alloys.

Based on JIS Z3001: Soldering terms, the above-mentioned solder particles are preferably a fusion material whose liquidus line is 450° C. or lower. The above-mentioned solder particles may contain, for example, lead, gold, lead, bismuth, and indium as metals other than tin, silver, and copper. The above-mentioned solder particles are preferably lead-free.

In order to further improve the bonding strength between the solder portion and the electrode, the solder particles may also include nickel, copper, antimony, aluminum, lead, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, chromium, molybdenum, and metals such as palladium. Moreover, it is preferable that the said solder particle contains nickel, copper, antimony, aluminum, or lead from a viewpoint of further improving the joint strength of a solder part and an electrode. From the viewpoint of further improving the bonding strength between the solder part and the electrode, the content of the metals used to increase the bonding strength is preferably 0.0001% by weight or more, preferably 1% by weight, in 100% by weight of the metal contained in the solder particles. Weight% or less.

The average particle diameter of the solder particles is preferably at least 0.01 μm, more preferably at least 0.05 μm, further preferably at least 0.1 μm, still more preferably at least 0.5 μm, and most preferably at least 1 μm. The average particle diameter of the above-mentioned solder particles is preferably 30 μm or less, more preferably 20 μm or less, further preferably 10 μm or less, particularly preferably less than 10 μm. If the average particle size of the solder particles is not less than the above-mentioned lower limit and not more than the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, and the conduction reliability between the upper and lower electrodes to be connected can be further effectively improved. The average particle diameter of the above-mentioned solder particles is more preferably not less than 0.5 μm and not more than 10 μm. When the average particle diameter of the said solder particle is 0.5 micrometer or more and 10 micrometers or less, solder particle|grains can connect densely, and a solder particle aggregates easily. When the average particle diameter of the said solder particle exceeds 10 micrometers, dense connection of solder particles may become difficult, and a solder particle may become difficult to aggregate. If the average particle diameter of the said solder particle is 10 micrometers or less, the effect of this invention will be exhibited more effectively, and a solder bump will be formed more uniformly. The average particle size of the above-mentioned solder particles is preferably smaller. Compared with solder particles of the same volume, when the average particle size of the solder particles is smaller, the distance between the solder particles becomes narrower, and the solder particles are more likely to agglomerate. Moreover, when the average particle diameter of a solder particle is small, it becomes easier to form a solder bump uniformly among several electrodes.

The average particle diameter of the above-mentioned solder particles is preferably a number average particle diameter. The average particle size of the solder particles is obtained by observing 50 arbitrary solder particles with an electron microscope or an optical microscope, calculating the average value of the particle sizes of the respective solder particles, or performing a laser diffraction particle size distribution measurement. In observation with an electron microscope or an optical microscope, the particle diameter per one solder particle was calculated|required as the particle diameter in circle-equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle diameter in terms of circle equivalent diameter and the average particle diameter in terms of spherical equivalent diameter of arbitrary 50 solder particles are substantially equal. In the laser diffraction particle size distribution measurement, the particle diameter per one solder particle was calculated|required as the particle diameter by spherical equivalent diameter. It is preferable to calculate the average particle diameter of the said solder particle by laser diffraction particle size distribution measurement.

The coefficient of variation (CV value) of the particle size of the solder particles is preferably at least 5%, more preferably at least 10%, preferably at most 40%, more preferably at most 30%. Solder can be arrange|positioned on an electrode more efficiently as the variation coefficient of the particle diameter of the said solder particle is more than the said minimum and below the said upper limit. However, the CV value of the particle diameter of the said solder particle may be less than 5%.

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

CV value (%)=(ρ/Dn)×100 ρ: Standard deviation of particle size of solder particles Dn: average particle size of solder particles

The shape of the above-mentioned solder particles is not particularly limited. The shape of the above-mentioned solder particles may be spherical, may be other than spherical, or may be flat or the like.

In 100% by weight of the above-mentioned conductive material, the content of the above-mentioned solder particles is preferably at least 15% by weight, more preferably at least 20% by weight, further preferably at least 30% by weight, especially preferably at least 40% by weight, and most preferably at least 50% by weight. % by weight or more. In 100% by volume of the above-mentioned conductive material, the content of the above-mentioned solder particles is preferably 95% by weight or less, more preferably 90% by weight or less, further preferably 85% by weight or less, especially preferably 80% by weight or less. If the content of the above-mentioned solder particles is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, a large amount of solder can be easily arranged between the electrodes, and the conduction reliability can be further improved. From the viewpoint of further improving conduction reliability, the content of the above-mentioned solder particles is preferably large.

(thermosetting components) The conductive material of the present invention contains a thermosetting component. The above-mentioned conductive material may also contain a thermosetting compound and a thermosetting agent as a thermosetting component. In order to harden the conductive material more favorably, the conductive material preferably contains a thermosetting compound and a thermosetting agent as a thermosetting component. In order to harden the conductive material more favorably, it is preferable that the above-mentioned conductive material contains a curing accelerator as a thermosetting component. In the present invention, solder particles with a relatively high melting point are used. It is preferable that the thermosetting component does not thermocure until the solder particles are aggregated. It is preferable that the above-mentioned thermosetting component controls the rate of hardening so as not to thermoharden until the solder is placed on the electrode even if it is heated to a relatively high temperature. The curing rate of the thermosetting component can be controlled according to the type and reaction initiation temperature of the thermosetting agent described below, the type and content of the curing accelerator described below, and the curing temperature.

(thermosetting component: thermosetting compound) The above-mentioned thermosetting compound is not particularly limited. Examples of the above-mentioned thermosetting compounds include: oxetane compounds, epoxy compounds, episulfide compounds, (meth)acrylic compounds, phenolic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicon Ketone compounds and polyimide compounds, etc. From the point of view of further improving the curability and viscosity of the conductive material, the point of view of further effectively improving the conduction reliability, and the point of view of further effectively improving the insulation reliability, epoxy compounds or episulfide compounds are preferred, and more Epoxy compounds are preferred. It is preferable that the said thermosetting compound contains an epoxy compound. The said thermosetting compound may use only 1 type, and may use 2 or more types together.

The above-mentioned epoxy compound is a compound having at least one epoxy group. Examples of the above-mentioned epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, phenolic novolak type epoxy compounds, biphenyl type epoxy compounds, bisphenol type epoxy compounds, and bisphenol type epoxy compounds. Phenol novolak type epoxy compound, biphenol type epoxy compound, naphthalene type epoxy compound, fennel type epoxy compound, phenol aralkyl type epoxy compound, naphthol aralkyl type epoxy compound, dicyclopentadiene Alkene-type epoxy compounds, anthracene-type epoxy compounds, epoxy compounds having an adamantane skeleton, epoxy compounds having a tricyclodecane skeleton, naphthyl ether-type epoxy compounds, and rings having a three-nucleus in the skeleton Oxygen compounds, etc. The said epoxy compound may use only 1 type, and may use 2 or more types together.

The epoxy compound is liquid or solid at normal temperature (23°C). When the epoxy compound is solid at normal temperature, the melting temperature of the epoxy compound is preferably below the melting point of the solder particles. By using the above-mentioned preferred epoxy compound, the viscosity is high at the stage of laminating the members to be connected, and the position of the first member to be connected and the second member to be connected can be suppressed when acceleration is applied due to impact such as transportation. offset. Furthermore, the viscosity of the conductive material can be greatly reduced by the heat during hardening, and the agglomeration of the solder can be performed efficiently.

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

It is preferable that the said thermosetting compound contains the thermosetting compound which has a polyether skeleton from a viewpoint of disposing solder on an electrode more efficiently.

Examples of the above-mentioned thermosetting compound having a polyether skeleton include compounds having a glycidyl ether group at both ends of an alkyl chain having 3 to 12 carbons, and a polyether skeleton having 2 to 4 carbons and having 2 A polyether-type epoxy compound, etc., is a structural unit formed by continuous bonding of 1 to 10 polyether skeletons.

It is preferable that the said thermosetting compound contains the thermosetting compound which has an isocyanuric acid skeleton from a viewpoint of improving the heat resistance of hardened|cured material more effectively.

Examples of the above-mentioned thermosetting compound having an isocyanuric acid skeleton include triisocyanurate-type epoxy compounds and the like, such as the TEPIC series (TEPIC-G, TEPIC-S, TEPIC- SS, TEPIC-HP, TEPIC-L, TEPIC-PAS, TEPIC-VL, TEPIC-UC), etc.

From the point of view of more efficiently disposing the solder on the electrodes, the point of view of further effectively improving the conduction reliability between the upper and lower electrodes to be connected, and the point of view of further effectively suppressing the discoloration of the thermosetting compound, the above thermal The hardening compound preferably has high heat resistance, and is more preferably a novolak type epoxy compound. Novolac-type epoxy compounds have relatively high heat resistance.

In the conductive material of the present invention, the content of the thermosetting compound is 10% by weight or more in 100% by weight of the conductive material. In 100% by weight of the above-mentioned conductive material, the content of the above-mentioned thermosetting compound is preferably at least 20% by weight, more preferably at least 40% by weight, further preferably at least 50% by weight, more preferably at most 99% by weight, and more preferably at least 99% by weight. It is 98% by weight or less, more preferably 90% by weight or less, especially preferably 80% by weight or less. If the content of the above-mentioned thermosetting compound is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, the insulation reliability between the electrodes can be further effectively improved, and the conduction between the electrodes can be further effectively improved. reliability. From the viewpoint of improving the impact resistance more effectively, the content of the above-mentioned thermosetting compound is preferably large.

In 100% by weight of the above-mentioned conductive material, the content of the above-mentioned epoxy compound is preferably at least 20% by weight, more preferably at least 40% by weight, further preferably at least 50% by weight, preferably at most 99% by weight, and more preferably at least 99% by weight. 98% by weight or less, more preferably 90% by weight or less, particularly preferably 80% by weight or less. If the content of the above-mentioned epoxy compound is more than the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, the insulation reliability between the electrodes can be further effectively improved, and the conduction reliability between the electrodes can be further effectively improved. sex. From the viewpoint of further improving the impact resistance, the content of the above-mentioned epoxy compound is preferably large.

(thermosetting component: thermosetting agent) The above-mentioned thermosetting agent is not particularly limited. The thermosetting agent thermosets the thermosetting compound. Examples of the thermosetting agent include imidazole curing agents, amine curing agents, phenolic curing agents, polymercaptan curing agents and other mercaptan curing agents, acid anhydride curing agents, thermal cationic initiators (thermal cationic curing agents), and thermal curing agents. Free radical generators, etc. Moreover, an amine complex compound can be used as said thermosetting agent. The said thermosetting agent may use only 1 type, and may use 2 or more types together.

From the viewpoint that the conductive material can be cured more quickly at low temperature, the above-mentioned thermosetting agent is preferably an imidazole curing agent, a mercaptan curing agent, or an amine curing agent. Moreover, it is preferable that the said thermosetting agent is a latent hardening agent from a viewpoint of improving the storage stability at the time of mixing the said thermosetting compound and the said thermosetting agent. The latent hardener is preferably a latent imidazole hardener, a latent mercaptan hardener or a latent amine hardener. Furthermore, the above-mentioned thermosetting agent may be coated with a polymer substance such as polyurethane resin or polyester resin.

The above-mentioned imidazole curing agent is not particularly limited. Examples of the imidazole curing agent include: 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-benzimidazole, 1-cyanoethyl-2-phenylimidazolium Trimellitic acid ester, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-trimethanone and 2,4-diamino-6-[2 '-Methylimidazolyl-(1')]-ethyl-s-tri-isocyanuric acid adduct, 2-phenyl-4,5-dimethylolimidazole, 2-phenyl-4 -Methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2-p-toluyl-4-methyl-5-hydroxymethylimidazole, 2- m-cresyl-4-methyl-5-hydroxymethylimidazole, 2-m-cresyl-4,5-dimethylolimidazole, 2-p-toluyl-4,5-dihydroxy 1H-imidazole such as methylimidazole, in which the hydrogen at the 5-position is replaced by a hydroxymethyl group and the hydrogen at the 2-position is replaced by a phenyl or toluyl group.

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

The aforementioned amine hardener is not particularly limited. Examples of the amine hardener include hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis(3-aminopropyl)-2,4,8, 10-tetraspiro[5.5]undecane, bis(4-aminocyclohexyl)methane, m-phenylenediamine and diaminodiphenylene, etc.

The above-mentioned acid anhydride curing agent is not particularly limited, and can be widely used as long as it is an acid anhydride used as a curing agent for thermosetting compounds such as epoxy compounds. Examples of the acid anhydride curing agent include: phthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride Acid anhydride, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, anhydride of phthalic acid derivatives, maleic anhydride, cyanide anhydride, methyl cyanide anhydride, Bifunctional anhydride hardeners such as glutaric anhydride, succinic anhydride, glycerin bis-trimellitic anhydride monoacetate, and ethylene glycol bis-trimellitic anhydride, trifunctional anhydride hardeners such as trimellitic anhydride, and homogeneous Tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, methylcyclohexene tetracarboxylic dianhydride, polyazelaic anhydride and other tetrafunctional or higher anhydride hardeners.

The aforementioned thermal cationic initiator is not particularly limited. Examples of the thermal cationic initiator include iodonium-based cationic hardeners, oxonium-based cationic hardeners, and perium-based cationic hardeners. Bis(4-t-butylphenyl)iodonium hexafluorophosphate etc. are mentioned as said iodide type cationic hardening agent. Examples of the oxonium-based cationic curing agent include trimethyloxonium tetrafluoroborate and the like. Tris-p-tolyl percite hexafluorophosphate etc. are mentioned as said permeicium type cationic hardening agent.

The aforementioned thermal radical generating agent is not particularly limited. As said thermal radical generating agent, an azo compound, an organic peroxide, etc. are mentioned. As said azo compound, azobisisobutyronitrile (AIBN) etc. are mentioned. Examples of the organic peroxide include di-tert-butyl peroxide, methyl ethyl ketone peroxide, and the like.

The above-mentioned amine complex compound is not particularly limited. As said amine complex compound, boron trifluoride-amine complex compound etc. are mentioned.

From the viewpoint of more efficiently disposing the solder on the electrodes and further effectively improving the conduction reliability between the electrodes to be connected above and below, the above-mentioned thermosetting agent is preferably an acid anhydride compound, more preferably an amine aluminum compound. compounds.

The reaction initiation temperature of the above thermosetting agent is preferably at least 50°C, more preferably at least 70°C, further preferably at least 80°C, more preferably at most 250°C, more preferably at most 200°C, even more preferably at 150°C °C or below, especially preferably below 140 °C. If the reaction initiation temperature of the said thermosetting agent is more than the said minimum and below the said upper limit, solder will be arrange|positioned on an electrode more efficiently. From the viewpoint of more efficiently disposing the solder on the electrodes and further effectively improving the conduction reliability between the upper and lower electrodes to be connected, the reaction initiation temperature of the above-mentioned thermosetting agent is preferably 80°C or higher. Below 140°C.

From the viewpoint of disposing the solder on the electrodes more efficiently, the reaction initiation temperature of the above-mentioned thermosetting agent is preferably higher than the melting point of the above-mentioned solder particles, more preferably at least 5°C higher, and more preferably at least 10°C higher. ℃ or more.

The reaction initiation temperature of the above-mentioned thermosetting agent means the temperature at which the exothermic peak in DSC starts to rise.

The content of the above-mentioned thermosetting agent is not particularly limited. With respect to 100 parts by weight of the above-mentioned thermosetting compound, the content of the above-mentioned thermosetting agent is preferably at least 0.01 parts by weight, more preferably at least 1 part by weight, preferably at most 200 parts by weight, more preferably at most 100 parts by weight, and further Preferably it is 75 parts by weight or less. If content of a thermosetting agent is more than the said minimum, it will become easy to fully harden a conductive material. If the content of the thermosetting agent is below the above-mentioned upper limit, the remaining thermosetting agent that does not participate in hardening after curing is less likely to remain, and the heat resistance of the cured product is further improved.

(thermosetting component: hardening accelerator) The above-mentioned conductive material may also contain a hardening accelerator. The above-mentioned hardening accelerator is not particularly limited. It is preferable that the said hardening accelerator functions as a hardening catalyst in the reaction of the said thermosetting compound and the said thermosetting agent. It is preferable that the said hardening accelerator functions as a hardening catalyst in reaction with the said thermosetting compound. The said hardening accelerator may use only 1 type, and may use 2 or more types 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, examples of the hardening accelerator include imidazole compounds, isocyanurates of imidazole compounds, dicyandiamide, derivatives of dicyandiamide, melamine compounds, derivatives of melamine compounds, diamine cis-butyl Diethylene nitrile, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, bis(hexamethylene)triamine, triethanolamine, diaminodiphenylmethane, organic acid dihydrazide Isoamine compounds, 1,8-diazabicyclo[5,4,0]undecene-7,3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxo Heterospiro[5,5]undecane, boron trifluoride, boron trifluoride-amine complex compounds, triphenylphosphine, tricyclohexylphosphine, tributylphosphine and methyldiphenylphosphine, etc. organophosphorus compounds, etc.

The above-mentioned phosphonium salt is not particularly limited. Examples of the above-mentioned phosphonium salts include: tetra-n-butylphosphonium bromide, tetra-n-butylphosphonium O,O-diethylphosphonodithioate, methyltributylphosphonium dimethylphosphate, tetra-n-butylphosphonium Benzotriazole, tetra-n-butylphosphonium tetrafluoroborate, tetra-n-butylphosphonium tetraphenylborate, etc.

From the viewpoint of more efficiently disposing the solder on the electrodes and further effectively improving the conduction reliability between the upper and lower electrodes to be connected, the above-mentioned hardening accelerator is preferably an imidazole compound, more preferably a trifluoro Boronium-amine complex compounds.

In order to make the said thermosetting compound harden|cure favorably, content of the said hardening accelerator is selected suitably. The content of the curing accelerator relative to 100 parts by weight of the thermosetting compound is preferably at least 0.5 parts by weight, more preferably at least 0.8 parts by weight, preferably at most 10 parts by weight, more preferably at most 8 parts by weight. When content of the said hardening accelerator is more than the said minimum and below the said upper limit, the said thermosetting compound can be hardened favorably. Moreover, if the content of the hardening accelerator is more than the above-mentioned lower limit and not more than the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, and the conduction reliability between the electrodes to be connected to the upper and lower electrodes can be further effectively improved.

(flux) The above-mentioned conductive material may also contain flux. By using flux, solder can be more efficiently placed on the electrodes. The aforementioned flux is not particularly limited. As said flux, the flux generally used for soldering etc. can be used. In the present invention, solder particles having a relatively high melting point are used, so the melting point of the flux can also be made relatively high. By using a flux with a relatively high melting point, the pot life of conductive materials can be further improved.

Examples of the aforementioned fluxes include: lead chloride, mixtures of lead chloride and inorganic halides, mixtures of lead chloride and inorganic acids, molten salts, phosphoric acid, derivatives of phosphoric acid, organic halides, hydrazine, amine compounds, Organic acids and rosin, etc. The above fluxes may be used alone or in combination of two or more.

Ammonium chloride etc. are mentioned as said molten salt. Lactic acid, citric acid, stearic acid, glutamic acid, glutaric acid, etc. are mentioned as said organic acid. As said rosin, activated rosin, non-activated rosin, etc. are mentioned. The aforementioned flux is preferably an organic acid having two or more carboxyl groups, or rosin. The above-mentioned flux may be an organic acid having two or more carboxyl groups, or may be rosin. The conduction reliability between electrodes is further improved by the use of organic acid and rosin having two or more carboxyl groups.

Examples of the organic acid 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 compound include cyclohexylamine, dicyclohexylamine, benzylamine, benzhydrylamine, imidazole, benzimidazole, benzimidazole, carboxybenzimidazole, benzotriazole, and carboxybenzotriazole wait.

The above-mentioned rosin is a rosin mainly composed of abietic acid. Examples of the aforementioned rosins include abietic acid, acrylic-modified rosins, and the like. The flux is preferably rosin, more preferably rosin acid. With the use of the preferred flux, the conduction reliability between the electrodes is further improved.

The activation temperature (melting point) of the above flux is preferably above 50°C, more preferably above 70°C, further preferably above 80°C, preferably below 250°C, more preferably below 200°C, even more preferably at 190°C °C or lower, more preferably 150 °C or lower, still more preferably 140 °C or lower. If the activation temperature of the said flux is more than the said minimum and below the said upper limit, the flux effect will be exhibited more effectively, and a solder will be arrange|positioned on an electrode more efficiently. From the viewpoint of more efficiently disposing the solder on the electrodes, the activation temperature (melting point) of the above-mentioned flux is preferably 90°C to 180°C, and the activation temperature (melting point) of the above-mentioned flux is particularly preferably 100°C or higher. Below 150°C.

In addition, the boiling point of the above-mentioned flux is preferably 200° C. or lower.

From the standpoint of disposing the solder on the electrodes more efficiently, the melting point of the flux is preferably higher than the melting point of the solder particles, more preferably 5°C or higher, further preferably 10°C or higher.

From the viewpoint of disposing the solder on the electrodes more efficiently, the melting point of the above-mentioned flux is preferably higher than the reaction initiation temperature of the above-mentioned thermosetting agent, more preferably 5°C or more higher, and still more preferably 10°C higher. ℃ or more.

The above flux can be dispersed in the conductive material, and can also be attached to the surface of the solder particles.

By making the melting point of the flux higher than the melting point of the solder particles, the solder can be efficiently aggregated on the electrode portion. The reason for this is that when heat is applied during bonding, comparing the electrode formed on the connection object member with the portion of the connection object member around the electrode, the thermal conductivity of the electrode portion is higher than the thermal conductivity of the connection object member portion around the electrode. Conductivity, and the temperature rise of the electrode part is faster. At the stage exceeding the melting point of the solder particle, the inside of the solder particle melts, but the oxide film formed on the surface does not reach the melting point (activation temperature) of the flux, so it is not removed. In this state, the temperature of the electrode part first reaches the melting point of the flux (activation temperature), so the oxide film on the surface of the solder particles that preferentially moves to the electrode is removed, and the solder can wet and diffuse to the surface of the electrode. Thereby, the solder can be efficiently agglomerated on the electrodes.

The above-mentioned flux is preferably a flux that releases cations by heating. By using a flux that releases cations by heating, the solder can be further efficiently disposed on the electrodes.

Examples of the flux that releases cations by heating include the aforementioned thermal cation initiators (thermal cation curing agents).

From the viewpoint of more efficiently disposing the solder on the electrodes, further effectively improving the insulation reliability, and further effectively improving the conduction reliability, the above-mentioned flux is preferably a salt of an acid compound and an alkali compound .

The above-mentioned acid compound is preferably an organic compound having a carboxyl group. Examples of the acid compound include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, citric acid, Malic acid, cyclohexyl carboxylic acid, 1,4-cyclohexyl dicarboxylic acid as cycloaliphatic carboxylic acid, isophthalic acid, terephthalic acid, trimellitic acid, and ethylene dicarboxylic acid as aromatic carboxylic acid Amine tetraacetic acid, etc. From the viewpoint of more efficiently disposing the solder on the electrodes, the viewpoint of further effectively improving the insulation reliability, and the viewpoint of further effectively improving the conduction reliability, the acid compound is preferably glutaric acid, cyclohexyl carboxyl acid, or adipic acid.

The above-mentioned base compound is preferably an organic compound having an amino group. Examples of the base compound 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 Amines, N,N-dimethylbenzylamine, imidazole compounds, and triazole compounds. The alkali compound is preferably benzylamine from the viewpoints of more efficiently disposing solder on the electrodes, further effectively improving insulation reliability, and further effectively improving conduction reliability.

In 100% by weight of the conductive material, the content of the above flux is preferably at least 0.5% by weight, preferably at most 30% by weight, more preferably at most 25% by weight. The above-mentioned conductive material may also not contain flux. If the content of the above-mentioned flux is more than the above-mentioned lower limit and below the above-mentioned upper limit, the oxide film is more difficult to form on the surface of the solder and the electrode, and further, the oxide film formed on the surface of the solder and the electrode can be removed more effectively.

(filler) The conductive material of the present invention may also contain fillers. Fillers can be organic fillers or inorganic fillers. By making the said conductive material contain a filler, solder can be aggregated uniformly on all electrodes of a board|substrate.

The above-mentioned conductive material preferably does not contain the above-mentioned filler, or contains the above-mentioned filler in an amount of 5% by weight or less. In the case of using the above-mentioned thermosetting compound, the smaller the content of the filler, the easier it is for the solder particles to move to the electrodes.

In 100% by weight of the conductive material, the content of the filler is preferably 0% by weight (not contained), preferably 5% by weight or less, more preferably 2% by weight or less, and more preferably 1% by weight or less. Solder is more uniformly arrange|positioned on an electrode as content of the said filler is more than the said minimum and below the said upper limit.

(other ingredients) The above-mentioned conductive materials, for example, may also include fillers, extenders, softeners, plasticizers, thixotropic agents, leveling agents, polymerization catalysts, hardening catalysts, colorants, antioxidants, heat stabilizers, light stabilizers, etc. additives, UV absorbers, lubricants, antistatic agents and flame retardants and other additives.

(Connection structure and method of manufacturing the connection structure) The connection structure of the present invention includes: a first connection object member having a first electrode on its surface; a second connection object member having a second electrode on its surface; and a connecting portion connecting the first connection object member to the above-mentioned The second connection object member is connected. In the connection structure of this invention, the material of the said connection part is the said conductive material. In the connection structure of this invention, the said 1st electrode and the said 2nd electrode are electrically connected by the solder part in the said connection part.

The method of manufacturing the connection structure of the present invention includes the step of disposing the above-mentioned conductive material on the surface of the first connection object member having the first electrode on the surface using the above-mentioned conductive material. The manufacturing method of the connection structure of the present invention has the following steps: on the surface of the above-mentioned conductive material opposite to the side of the first connection object member, the second connection object member having the second electrode on the surface, the above-mentioned first electrode and the above-mentioned The second electrodes are arranged in a facing manner. The method for manufacturing a connection structure according to the present invention includes the step of: forming a connection between the first connection object member and the second connection object member by using the above-mentioned conductive material by heating the above-mentioned conductive material to a temperature equal to or higher than the melting point of the solder particles. a connection part, and electrically connect the first electrode and the second electrode through the solder part in the connection part.

In the connection structure and the method of manufacturing the connection structure of the present invention, the specific conductive material is used, so the solder is easy to gather between the first electrode and the second electrode, and the solder can be efficiently arranged on the electrodes (lines) . In addition, part of the solder is less likely to be placed in the region (gap) where no electrode is formed, and the amount of solder placed in the region where no electrode is formed can be reduced. Therefore, the conduction reliability between the first electrode and the second electrode can be improved. In addition, electrical connection between laterally adjacent electrodes that should not be connected can be prevented, and insulation reliability can be improved.

In addition, in order to efficiently place solder on the electrodes and reduce the amount of solder placed on the region where no electrodes are formed, it is preferable to use a conductive paste instead of a conductive film as the conductive material.

The thickness of the solder portion between the electrodes is preferably at least 10 μm, more preferably at least 20 μm, preferably at most 100 μm, and more preferably at most 80 μm. The solder wetting area on the surface of the electrode (the area where the solder contacts 100% of the exposed area of the electrode) is preferably 50% or more, more preferably 70% or more, and more preferably 100% or less.

In the method for manufacturing a connection structure of the present invention, it is preferable that the second connection object is applied to the conductive material without applying pressure in the step of arranging the second connection object member and the step of forming the connection portion. The weight of the component. In the method for manufacturing a connection structure of the present invention, it is preferable not to apply a force exceeding the weight of the second connection object member to the conductive material in the step of arranging the second connection object member and the step of forming the connection portion. of pressurized pressure. In such cases, the uniformity of the amount of solder can be further improved in a plurality of solder portions. Furthermore, the thickness of the solder portion can be further effectively increased, a large amount of solder tends to gather between the electrodes, and the solder can be more efficiently arranged on the electrodes (lines). In addition, part of the solder is less likely to be placed in the region (gap) where no electrode is formed, and the amount of solder placed in the region where no electrode is formed can be further reduced. Therefore, the conduction reliability between electrodes can be further improved. In addition, electrical connection between electrodes adjacent in the lateral direction that should not be connected can be further prevented, and insulation reliability can be further improved.

Also, by using the conductive paste instead of the conductive film, it is easy to adjust the thickness of the connection portion and the solder portion according to the coating amount of the conductive paste. On the other hand, in the conductive film, in order to change or adjust the thickness of the connection portion, there is a problem that it is necessary to prepare a conductive film having a different thickness or to prepare a conductive film with a specific thickness. Moreover, compared with the conductive paste, the conductive film tends not to lower the melt viscosity of the conductive film sufficiently at the melting temperature of the solder, and it tends to hinder the aggregation of the solder more easily.

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 connection structure obtained by using a conductive material according to an embodiment of the present invention.

The connection structure 1 shown in FIG. 1 is equipped with the 1st connection object member 2, the 2nd connection object member 3, and the connection part 4 which connects the 1st connection object member 2 and the 2nd connection object member 3. As shown in FIG. The connection portion 4 is formed of the above-mentioned conductive material. In the present embodiment, the conductive material includes a thermosetting component and solder particles. The above-mentioned thermosetting component includes a thermosetting compound and a thermosetting agent. In this embodiment, conductive paste is used as the conductive material.

The connecting portion 4 has a solder portion 4A in which a plurality of solder particles are gathered and bonded together, and a hardened portion 4B in which a thermosetting compound is thermally cured.

The 1st connection object member 2 has the some 1st electrode 2a on the surface (upper surface). The 2nd connection object member 3 has the some 2nd electrode 3a on the surface (lower surface). The first electrode 2a and the second electrode 3a are electrically connected by the solder portion 4A. Therefore, the first connection object member 2 and the second connection object member 3 are electrically connected by the solder portion 4A. In addition, in the connection part 4, the solder does not exist in the area|region (cured part part 4B part) different from the solder part 4A gathered between the 1st electrode 2a and the 2nd electrode 3a. In a region different from the solder portion 4A (hardened portion 4B portion), there is no solder separated from the solder portion 4A. In addition, if it is a small amount, solder may also exist in the area|region (cured part 4B part) different from the solder part 4A gathered between the 1st electrode 2a and the 2nd electrode 3a.

As shown in Fig. 1, in the connection structure 1, a plurality of solder particles are gathered between the first electrode 2a and the second electrode 3a, and after the plurality of solder particles are melted, the molten material of the solder particles wets and spreads on the surface of the electrodes. After curing, the solder portion 4A is formed. Therefore, the connection area between 4 A of solder parts and the 1st electrode 2a, and 4 A of solder parts and the 2nd electrode 3a becomes large. That is, by using solder particles, the solder portion 4A and the first electrode 2a, and the solder portion 4A and the second electrode 3a are more stable than the case of using conductive particles whose outer conductive surface is metal such as nickel, gold, or copper. The contact area becomes larger. This also improves the conduction reliability and connection reliability of the connection structure 1 . Furthermore, when flux is included in the conductive material, the flux is generally gradually inactivated by heating.

Furthermore, in the connection structure 1 shown in FIG. 1, all the solder parts 4A are located in the opposing area|region between the 1st, 2nd electrode 2a, 3a. The connection structure 1X of the modification shown in FIG. 3 is different from the connection structure 1 shown in FIG. 1 only in the connection part 4X. The connecting portion 4X has a solder portion 4XA and a cured portion 4XB. Like the connection structure 1X, many solder parts 4XA are located in the area facing the first and second electrodes 2a and 3a, and a part of the solder part 4XA is directed from the area facing the first and second electrodes 2a and 3a. The side is exposed. The solder portion 4XA exposed laterally from the region where the first and second electrodes 2a, 3a face each other is part of the solder portion 4XA, and is not solder separated from the solder portion 4XA. Furthermore, in this embodiment, although the amount of the solder separated from the solder part can be reduced, the solder separated from the solder part may exist in the cured product part.

If the amount of solder particles used is reduced, the connection structure 1 can be easily obtained. When the usage-amount of a solder particle increases, it becomes easy to obtain connection structure 1X.

In the connection structure 1, 1X, it is preferable to look at the part where the first electrode 2a and the second electrode 3a face each other toward the layering direction of the first electrode 2a, the connection part 4, 4X, and the second electrode 3a. Solder portions 4A, 4XA in connection portions 4, 4X are arranged in more than 50% of 100% of the area of the portion where the first electrode 2a and the second electrode 3a face each other. By making the solder portions 4A, 4XA in the connection portions 4, 4X satisfy the above-mentioned preferred aspects, the conduction reliability can be further improved.

Preferably, when the portion where the first electrode and the second electrode face each other is viewed toward the lamination direction of the first electrode, the connection portion, and the second electrode, when the first electrode and the second electrode face each other, More than 50% of 100% of the area of the facing part is arranged with the solder part in the above-mentioned connecting part. More preferably, when the portion where the first electrode and the second electrode face each other is viewed toward the layering direction of the first electrode, the connection portion, and the second electrode, when the first electrode and the second electrode face each other, More than 60% of 100% of the area of the facing part is provided with the solder part in the above-mentioned connecting part. Furthermore, it is preferable that when the portion where the first electrode and the second electrode face each other is viewed toward the lamination direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode are mutually opposite to each other. More than 70% of 100% of the area of the facing part is arranged with the solder part in the above-mentioned connecting part. More preferably, when the portion where the first electrode and the second electrode face each other is viewed toward the layering direction of the first electrode, the connection portion, and the second electrode, when the first electrode and the second electrode face each other, More than 80% of 100% of the area of the facing part is arranged with the solder part in the above-mentioned connecting part. Preferably, when the portion where the first electrode and the second electrode face each other is viewed toward the layering direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode face each other. More than 90% of 100% of the area of the facing part is arranged with the solder part in the above-mentioned connecting part. The conduction reliability can be further improved by making the solder part in the above-mentioned connection part satisfy the above-mentioned preferred aspect.

Preferably, when the portion facing each other of the first electrode and the second electrode is viewed in a direction perpendicular to the lamination direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode More than 60% of the solder portion of the above-mentioned connecting portion is arranged at the portion where the second electrodes face each other. More preferably, when the portion facing each other of the first electrode and the second electrode is viewed in a direction perpendicular to the lamination direction of the first electrode, the connection portion, and the second electrode, the More than 70% of the solder portion of the above-mentioned connecting portion is arranged at the portion where the second electrodes face each other. Furthermore, it is preferable that when the portion facing each other of the first electrode and the second electrode is viewed in a direction perpendicular to the stacking direction of the first electrode, the connection portion, and the second electrode, the first electrode and the second electrode are More than 90% of the solder portion in the connection portion is disposed on the portion where the second electrodes face each other. More preferably, when the portion facing each other of the first electrode and the second electrode is viewed in a direction perpendicular to the stacking direction of the first electrode, the connection portion, and the second electrode, the More than 95% of the solder portion of the above-mentioned connecting portion is disposed on the portion where the second electrodes face each other. Preferably, when the portion facing each other of the first electrode and the second electrode is viewed in a direction perpendicular to the stacking direction of the first electrode, the connection portion, and the second electrode, the More than 99% of the solder portion of the above-mentioned connecting portion is disposed on the portion where the second electrodes face each other. The conduction reliability can be further improved by making the solder part in the above-mentioned connection part satisfy the above-mentioned preferred aspect.

Next, in FIG. 2, an example of the method of manufacturing the connection structure 1 using the electrically-conductive material which concerns on one Embodiment of this invention is demonstrated.

First, the 1st connection object member 2 which has the 1st electrode 2a on the surface (upper surface) is prepared. Next, as shown in FIG. 2( a ), conductive material 11 including thermosetting component 11B and solder particles 11A is arranged on the surface of first connection object member 2 (first step). The conductive material 11 used contains a thermosetting compound and a thermosetting agent as a thermosetting component 11B.

The conductive material 11 is arranged on the surface of the first connection object member 2 on which the first electrode 2a is provided. After the conductive material 11 is arranged, the solder particles 11A are arranged on both the first electrode 2a (line) and the region (gap) where the first electrode 2a is not formed. Furthermore, the above-mentioned conductive material may be arranged only on the surface of the above-mentioned first electrode.

The method of arranging the conductive material 11 is not particularly limited, and examples thereof include coating with a dispenser, screen printing, and discharge with an inkjet device.

Moreover, the 2nd connection object member 3 which has the 2nd electrode 3a on the surface (lower surface) is prepared. Next, as shown in Figure 2(b), in the conductive material 11 on the surface of the first connection object member 2, the second connection is arranged on the surface of the conductive material 11 opposite to the first connection object member 2 side. Object member 3 (step 2). The second connection object member 3 is arranged on the surface of the conductive material 11 from the side of the second electrode 3a. At this time, the 1st electrode 2a and the 2nd electrode 3a are made to oppose.

Next, the conductive material 11 is heated to a temperature equal to or higher than the melting point of the solder particles 11A (third step). Preferably, the conductive material 11 is heated above the curing temperature of the thermosetting component 11B (thermosetting compound). At the time of this heating, 11 A of solder particles which exist in the area|region where no electrode is formed gather between the 1st electrode 2a and the 2nd electrode 3a (self-aggregation effect). When using a conductive paste instead of a conductive film, the solder particles 11A are more efficiently gathered between the first electrode 2a and the second electrode 3a. Also, the solder particles 11A are melted and bonded to each other. Also, the thermosetting component 11B is thermally cured. As a result, as shown in FIG. 2( c ), the connection portion 4 connecting the first connection object member 2 and the second connection object member 3 is formed of the conductive material 11 . The connection part 4 is formed of the conductive material 11, the solder part 4A is formed by bonding a plurality of solder particles 11A, and the cured part 4B is formed by thermosetting of the thermosetting component 11B. If the solder particle 11A moves sufficiently, after the movement of the solder particle 11A not located between the first electrode 2a and the second electrode 3a starts, the temperature may not be kept constant until the movement of the solder particle 11A between the first electrode 2a and the second electrode 3a. between the second electrodes 3a is completed.

In this embodiment, it is preferable not to pressurize in the above-mentioned second step and the above-mentioned third step. In this case, the weight of the second connection object member 3 is applied to the conductive material 11 . Therefore, when the connection portion 4 is formed, the solder particles 11A gather more efficiently between the first electrode 2 a and the second electrode 3 a. Furthermore, when the pressure is applied in at least one of the above-mentioned second step and the above-mentioned third step, the tendency to inhibit the action of the solder particles 11A to gather between the first electrode 2 a and the second electrode 3 a becomes high.

In addition, in this embodiment, no pressure is applied, so in the state where the alignment of the first electrode 2a and the second electrode 3a is shifted, when the first connection object member 2 and the second connection object member 3 overlap , the offset can be corrected to connect the first electrode 2a and the second electrode 3a (self-alignment effect). The reason is that, regarding the molten solder self-agglomerated between the first electrode 2a and the second electrode 3a, the area where the solder between the first electrode 2a and the second electrode 3a is in contact with other components of the conductive material is the smallest has stable energy. , the force applied to the connection structure with the smallest area, that is, the connection structure that has alignment, will play a role. At this time, it is desirable that the conductive material is not hardened, and that the viscosity of the components other than the solder particles of the conductive material is sufficiently low at the temperature and time.

In this way, the connection structure 1 shown in FIG. 1 is obtained. Furthermore, the above-mentioned second step and the above-mentioned third step may be performed continuously. Also, after performing the above-mentioned second step, the obtained laminate of the first connection object member 2, the conductive material 11, and the second connection object member 3 may be moved to a heating section to perform the above-mentioned third step. In order to perform the above-mentioned heating, the above-mentioned laminated body may be arranged on a heating member, or the above-mentioned laminated body may be arranged in a heated space.

The heating temperature in the third step is preferably 140°C or higher, more preferably 160°C or higher, more preferably 450°C or lower, more preferably 250°C or lower, still more preferably 220°C or lower. If the above-mentioned heating temperature in the above-mentioned third step is above the above-mentioned lower limit and below the above-mentioned upper limit, the solder can be more efficiently arranged on the electrodes, and the conduction reliability between the upper and lower electrodes to be connected can be further effectively improved.

As the heating method in the above-mentioned third step, a method of heating the entire connection structure to a temperature above the melting point of the solder particles and above the hardening temperature of the thermosetting component by using a reflow furnace or an oven, or heating only the connection structure The method of locally heating the connection part.

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

Also, when heating locally with a heating plate, it is preferable to use a metal with high thermal conductivity directly below the connection to form the upper surface of the heating plate, and use a material with low thermal conductivity such as fluororesin to form a heating plate for other parts that are not well heated. upper surface.

The above-mentioned first and second connection object members are not particularly limited. Specific examples of the first and second connection object 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, Flexible flat cables, rigid flexible substrates, glass epoxy substrates, and electronic components such as circuit substrates such as glass substrates, etc. It is preferable that the said 1st, 2nd connection object member is an electronic component.

At least one of the first connection object member and the second connection object member is preferably a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. The second connection object member is preferably a resin film, a flexible printed circuit board, a flexible flat cable, or a rigid flexible substrate. Resin films, flexible printed substrates, flexible flat cables and rigid flexible substrates have high flexibility and relatively light weight. When a conductive film is used for the connection of such connection target members, there is a tendency that solder is less likely to accumulate on the electrodes. In contrast, by using conductive paste, even if resin film, flexible printed circuit board, flexible flat cable or rigid flexible substrate is used, solder can be efficiently gathered on the electrodes, thereby fully improving the conduction reliability between electrodes . In the case of using a resin film, flexible printed circuit board, flexible flat cable, or rigid flexible substrate, compared with the case of using other connection object members such as semiconductor chips, the gap between electrodes caused by not applying pressure is further effectively obtained. Improvement of conduction reliability.

Metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS (Steel Use Stainless, stainless steel) electrodes, and tungsten electrodes are examples of the electrodes provided on the above-mentioned member to be connected. . When the above-mentioned member to be connected is a flexible printed circuit board, the above-mentioned 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. Furthermore, when the above-mentioned electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or may be an electrode in which an aluminum layer is layered 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, lead oxide doped with a trivalent metal element, and the like. As said trivalent metal element, Sn, Al, Ga, etc. are mentioned.

In the connection structure of the present invention, it is preferable that the first electrode and the second electrode are arranged in an area array or as a peripheral device. When the above-mentioned first electrode and the above-mentioned second electrode are arranged in an area array or a peripheral device, the effect of the present invention can be more effectively exhibited. The above-mentioned area array refers to a structure in which electrodes are arranged in a grid pattern on the surface of the member to be connected to which electrodes are arranged. The aforementioned peripheral device refers to a structure in which electrodes are disposed on the outer peripheral portion of the member to be connected. In the case of a structure in which the electrodes are arranged in a comb-like shape, it is only necessary for the solder to agglomerate along the direction perpendicular to the comb. In contrast, in the above-mentioned area array or peripheral device structure, the surface on which the electrodes are arranged needs to be evenly distributed. Condensed on the entire surface. Therefore, in the conventional method, the amount of solder tends to become non-uniform, but in the method of the present invention, the solder can be uniformly aggregated on the entire surface.

Hereinafter, an Example and a comparative example are given, and this invention is demonstrated concretely. The present invention is not limited to the following examples.

Thermosetting ingredients (thermosetting compounds): Thermosetting compound 1: "D.E.N-431" manufactured by Dow Chemical Company, epoxy resin Thermosetting compound 2: "jER152" manufactured by Mitsubishi Chemical Corporation, epoxy resin

Thermosetting ingredients (thermosetting agent): Thermosetting agent 1: "BF3-MEA" manufactured by Tokyo Chemical Industry Co., Ltd., boron trifluoride-monoethylamine complex Thermosetting agent 2: "2PZ-CN" manufactured by Shikoku Chemical Industry Co., Ltd., 1-cyanoethyl-2-benzimidazole

Solder particles: Solder particle 1: SnAg3Cu0.5 solder particle, melting point 220°C, average particle size 0.05 μm Solder particle 2: SnAg3Cu0.5 solder particle, melting point 220°C, average particle size 0.1 μm Solder particle 3: SnAg3Cu0.5 solder particle, melting point 220°C, average particle size 0.5 μm Solder particle 4: SnAg3Cu0.5 solder particle, melting point 220°C, average particle size 2 μm Solder particle 5: SnAg3Cu0.5 solder particle, melting point 220°C, average particle size 10 μm Solder particle 6: Sn42Bi58 solder particle, melting point 139°C, average particle size 2 μm Solder particle 7: Sn42Bi58 solder particle, melting point 139°C, average particle size 10 μm Solder particle 8: Sn42Bi58 solder particle, melting point 139°C, average particle size 0.05 μm

Flux: Flux 1: "Benzylamine glutarate", melting point 108°C

The production method of 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 put into a glass bottle, and dissolved at room temperature until uniform. Thereafter, 10.715 g of benzylamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for about 5 minutes to obtain a liquid mixture. The obtained mixture was put into a refrigerator at 5° C. to 10° C. and left overnight. The precipitated crystals were collected by filtration, washed with water, and vacuum-dried to obtain flux 1.

(Examples 1-6 and Comparative Examples 1-4) (1) Production of conductive materials (anisotropic conductive paste) The components shown in the following Tables 1 and 2 were prepared according to the compounding amounts shown in the following Tables 1 and 2 to obtain a conductive material (anisotropic conductive paste).

(2) Fabrication of the connection structure As the second connection target member, prepare a semiconductor wafer, which is provided with a copper electrode (second electrode, size 150 μm × 250 μm, planar area 37.5×10 ³ μm ² ), and a passivation film (polyimide, thickness 5 μm, opening diameter of the electrode portion 200 μm) is formed on the outermost surface. The number of copper electrodes was 100 pieces in total of 10 pieces×10 pieces per 1 semiconductor wafer.

As the first connection object member, prepare a glass epoxy substrate, which is the same as the electrode of the second connection object member on the surface of the glass epoxy substrate body (size 20×20 mm, thickness 1.2 mm, material FR-4) A copper electrode (first electrode) is arranged in a pattern, and a solder resist film is formed in a region where the copper electrode is not arranged. The step difference between the surface of the copper electrode and the surface of the solder resist film was 15 μm, and the solder resist film protruded more than the copper electrode.

The conductive material (anisotropic conductive paste) immediately after production was coated (coated amount: 1 mg) on the upper surface of the above-mentioned glass epoxy substrate so as to have a thickness of 30 μm to form an anisotropic conductive paste layer. Next, on the upper surface of the anisotropic conductive paste layer, semiconductor wafers are laminated in such a manner that the electrodes face each other. The above weight of the semiconductor wafer was applied to the anisotropic conductive paste layer. From this state, it heated so that the temperature of the anisotropic conductive paste layer might become the melting point of the solder 5 seconds after starting to heat up. Furthermore, after 15 seconds from the start of temperature rise, it heated so that the temperature of the anisotropic conductive paste layer might become 160 degreeC, the anisotropic conductive paste layer was hardened, and the bonded structure was obtained. During heating, no pressurization was performed.

(evaluate) (1) Average particle size of solder particles The average particle diameter of the said solder particle was measured using the laser diffraction particle size distribution measuring apparatus ("LA-920" by Horiba Corporation).

(2) Contents of tin, silver, and copper in 100% by weight of metal contained in solder particles The contents of tin, silver, and copper in 100% by weight of metal contained in solder particles were measured using a high-frequency inductively coupled plasma emission spectrometer ("ICP-AES" manufactured by Horiba, Ltd.).

(3) Viscosity (η25) of conductive material at 25°C and 5 rpm immediately after fabrication The viscosity (η25) at 25° C. and 5 rpm of the obtained conductive material (anisotropic conductive paste) immediately after production was measured using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.).

(4) Viscosity (ηA) of the conductive material at 25°C and 5 rpm immediately after thawing the conductive material stored in the freezer The obtained conductive material (anisotropic conductive paste) was stored frozen at -20° C. for 7 days. Next, the electrically conductive material frozen and stored was stored at 25° C. for 2 hours and thawed. Use an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) to measure the viscosity of the conductive material at 25°C and 5 rpm after thawing the above-mentioned conductive material that has been stored in a freezer (that is, after 2 hours at 25°C). Viscosity (ηA).

(5) Thixotropic index (ηB/ηA) The obtained conductive material (anisotropic conductive paste) was stored frozen at -20° C. for 7 days. Next, the electrically conductive material frozen and stored was stored at 25° C. for 2 hours and thawed. Use an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.) to measure the viscosity of the conductive material at 25°C and 0.5 rpm after thawing the above-mentioned conductive material that has been stored in a freezer (that is, after 2 hours at 25°C). Viscosity (ηB).

From the measurement results of ηA and ηB in the evaluation of (4) above, calculate the viscosity (ηB) of the conductive material at 25°C and 0.5 rpm after thawing the above-mentioned conductive material that has been frozen and stored Thixotropic index (ηB/ηA) obtained from the viscosity (ηA) of the conductive material after the above conductive material at 25°C and 5 rpm.

(6) Storage stability 1 The viscosity increase rate (ηA/η25) was calculated from the measurement results of η25 in the evaluation of (3) above and ηA in the evaluation of (4) above. Storage stability 1 was judged according to the following criteria.

[Criteria for judging storage stability 1] ○: Viscosity increase rate (ηA/η25) is 1.2 or less △: Viscosity increase rate (ηA/η25) exceeds 1.2 and is 1.5 or less ×: Viscosity increase rate (ηA/η25) exceeds 1.5

(7) Storage stability 2 The obtained conductive material (anisotropic conductive paste) was stored at 25° C. for 24 hours. The viscosity (ηC) of the conductive material after storage at 25° C. and 5 rpm was measured using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.).

The viscosity increase rate (ηC/η25) was calculated from the measurement results of η25 in the evaluation of (3) above and the above ηC. Storage stability 2 was judged according to the following criteria.

[Criteria for judging storage stability 2] ○: The rate of viscosity increase (ηC/η25) is 1.2 or less △: Viscosity increase rate (ηC/η25) exceeds 1.2 and is 1.5 or less ×: Viscosity increase rate (ηC/η25) exceeds 1.5

(8) Agglomeration of solder particles Regarding the obtained connection structure, the connection part was observed with the scanning electron microscope, and it confirmed whether the solder particle aggregated and whether the solder particle mutually bonded. The agglomeration of solder was judged according to the following criteria.

[Criteria for judging the agglomeration of solder] ○: Solder particles are aggregated, and solder particles are joined to each other ×: Solder particles are aggregated, and solder particles are not bonded to each other

(9) Conduction reliability between the upper and lower electrodes For the obtained connection structures (n=15 pieces), the connection resistance of each connection site between the upper and lower electrodes was measured by the four-probe method. Calculate the average value of the connection resistance. Furthermore, the connection resistance can be obtained by measuring the voltage when a certain current flows from the relationship of voltage=current×resistance. The conduction reliability is judged according to the following criteria.

[Criteria for judging conduction reliability] ○○: The average connection resistance is 50 mΩ or less ○: The average connection resistance exceeds 50 mΩ and is 70 mΩ or less △: The average connection resistance exceeds 70 mΩ and is 100 mΩ or less ×: The average value of connection resistance exceeds 100 mΩ, or poor connection occurs

(10) Conduction reliability between the upper and lower electrodes (after high temperature reflow) The connection structure used for the evaluation of (9) above was prepared. These connected structures were heated by high-temperature reflow (5 times of reflow at 260° C.). For the heated connection structure (n=15 pieces), the connection resistance of each connection site between the upper and lower electrodes was measured by the four-probe method. Calculate the average value of the connection resistance. Furthermore, the connection resistance can be obtained by measuring the voltage when a certain current flows from the relationship of voltage=current×resistance. Conduction reliability is judged according to the following criteria (after high temperature reflow).

[Judgement criteria for conduction reliability (after high temperature reflow)] ○○: The average connection resistance is 50 mΩ or less ○: The average connection resistance exceeds 50 mΩ and is 70 mΩ or less △: The average connection resistance exceeds 70 mΩ and is 100 mΩ or less ×: The average value of connection resistance exceeds 100 mΩ, or poor connection occurs

The results are shown in Tables 1 and 2 below.

[表2]

[Table 1]

[Table 2]

The same tendency was also observed when flexible printed circuit boards, resin films, flexible flat cables, and rigid flexible substrates were used.

1‧‧‧connection structure 1X‧‧‧connection structure 2‧‧‧The first connection object component 2a‧‧‧1st electrode 3‧‧‧The second connection target member 3a‧‧‧Second electrode 4‧‧‧connection part 4X‧‧‧Connection 4A‧‧‧Solder Department 4XA‧‧‧Solder Department 4B‧‧‧hardening department 4XB‧‧‧hardened parts department 11‧‧‧Conductive materials 11A‧‧‧Solder particles 11B‧‧‧thermosetting components

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

Claims (12)

A conductive material comprising a thermosetting component and a plurality of solder particles, the solder particles comprising tin, silver, and copper, the thermosetting component comprising a thermosetting compound, and in 100% by weight of the conductive material, the thermosetting compound The content is more than 10% by weight, and the viscosity of the conductive material at 25°C and 0.5 rpm after thawing the above-mentioned conductive material that has been frozen and stored is divided by the viscosity of the conductive material that has just been thawed and kept frozen. The thixotropic index obtained from the viscosity at 5 rpm is above 2. A conductive material comprising a thermosetting component and a plurality of solder particles, the solder particles comprising tin, silver, and copper, the thermosetting component comprising a thermosetting compound, and in 100% by weight of the conductive material, the thermosetting compound The content of the conductive material is more than 10% by weight, and the viscosity of the conductive material at 25°C and 5rpm after storing the above-mentioned conductive material just after production under the conditions of 25°C and 24 hours is relative to that of the above-mentioned conductive material immediately after production at 25°C And the ratio of the viscosity at 5 rpm is 1.2 or less. A conductive material comprising a thermosetting component and a plurality of solder particles, the solder particles comprising tin, silver, and copper, the thermosetting component comprising a thermosetting compound, In 100% by weight of the conductive material, the content of the above-mentioned thermosetting compound is more than 10% by weight, and the viscosity of the conductive material at 25°C and 5 rpm after thawing the above-mentioned conductive material that has been refrigerated and stored is relatively higher than that of the above-mentioned conductive material just after production. The viscosity ratio of the material at 25° C. and 5 rpm is 1.2 or less. The conductive material according to any one of claims 1 to 3, wherein the average particle diameter of the above-mentioned solder particles is 10 μm or less. The conductive material according to any one of Claims 1 to 3, wherein the viscosity of the conductive material at 25° C. and 5 rpm after thawing and storing the conductive material is above 100 Pa‧s. The conductive material according to any one of Claims 1 to 3, which is used for the installation of electronic components whose electrodes have a planar area of 70×10 ³ μm ² or less. The conductive material according to claim 6, wherein the above-mentioned electronic components are semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors, or diodes. The conductive material according to any one of claims 1 to 3, which is a conductive paste. A connection structure comprising: a first connection object member having a first electrode on its surface; a second connection object member having a second electrode on its surface; and A connection part, which connects the first connection object member to the second connection object member; the material of the connection part is a conductive material according to any one of claims 1 to 8; and the first electrode and the second electrode It is electrically connected through the solder part in the above-mentioned connection part. The connection structure according to claim 9, wherein when the portion of the first electrode and the second electrode facing each other is viewed in the lamination direction of the first electrode, the connection portion, and the second electrode, the first electrode The solder portion in the connection portion is arranged in more than 50% of 100% of the area of the portion facing the second electrode. A method for manufacturing a connection structure, comprising the steps of: using the conductive material according to any one of claims 1 to 8, disposing the above-mentioned conductive material on the surface of a first connection object member having a first electrode on the surface; On the surface of the conductive material opposite to the side of the first connection object member, a second connection object member having a second electrode on the surface is arranged in such a manner that the first electrode and the second electrode face each other; The material is heated above the melting point of the solder particles, and the connection part connecting the first connection object member and the second connection object member is formed by the above-mentioned conductive material, and the above-mentioned first electrode is connected by the solder part in the connection part. It is electrically connected with the above-mentioned second electrode. The method of manufacturing a connection structure according to claim 11, which obtains the connection structure, the connection structure being viewed in the lamination direction of the first electrode, the connection part, and the second electrode When looking at the portion where the first electrode and the second electrode face each other, the solder portion of the connecting portion is arranged on 50% or more of the 100% area of the portion where the first electrode and the second electrode face each other .

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