KR101982034B1 - Anisotropic conductive paste and electronic component connecting method using the same - Google Patents
Anisotropic conductive paste and electronic component connecting method using the same Download PDFInfo
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Abstract
The anisotropic conductive paste of the present invention is an anisotropic conductive paste for connecting an electronic component and a wiring board. The anisotropic conductive paste contains 10% by mass or more and 50% by mass or less of lead-free solder powder having a melting point of 240 占 폚 or less and 50% by mass or more and 90% by mass or less of a thermosetting resin composition containing a thermosetting resin and an organic acid, And the acid value of the thermosetting resin composition is 15 mgKOH / g or more and 55 mgKOH / g or less.
Description
The present invention relates to an anisotropic conductive paste for connecting an electronic component and a wiring board, and a connection method of an electronic component using the anisotropic conductive paste.
BACKGROUND ART [0002] In recent years, a connection method using an anisotropic conductive material (anisotropic conductive film, anisotropic conductive paste) is used for connection between an electronic component and a wiring board. For example, when an electronic component and a wiring board are connected to each other, an anisotropic conductive material is disposed between the electronic component on which the electrode is formed and the wiring board on which the electrode pattern is formed, and the electronic component and the wiring substrate are thermally bonded to each other to secure electrical connection .
As an anisotropic conductive material, for example, there has been proposed a material for dispersing a conductive filler such as a resin ball in which a metal film or a conductive film is formed on a binder resin serving as a base (see, for example, Japanese Patent Application Laid- 165825). When the electronic component and the wiring substrate are thermocompression bonded, the conductive filler is arranged in a planar state because there is a predetermined probability between the electrodes of the electronic component to be connected and the electrodes of the wiring substrate. In this way, the electrodes of the electronic components to be connected and the electrodes of the wiring board are brought into contact with each other through the conductive filler, so that the conductivity between these electrodes is secured. On the other hand, at the gap between the electrodes of the electronic component and the gap between the electrodes of the wiring board, the conductive filler is embedded in the binder resin, and insulation in the plane direction is secured.
However, in the above-described mounting method, when a problem such as a positional deviation due to conduction failure or pressing occurs in the mounting state of the electronic component after thermocompression, the electronic component or the anisotropic conductive film is mechanically peeled off, The residue of the residue is wiped off with a solvent or the like to purify and reuse the wiring substrate. Thus, the anisotropic conductive material after thermocompression is not only required to have sufficient mechanical strength because the thermosetting resin is cured, but also has sufficient reparability (it is possible to peel the anisotropic conductive material from the wiring board with no residue or with a small amount of residue, A property of being able to connect the wiring board with the electronic component by using the wiring board).
However, in the anisotropic conductive material described in Document 1, it takes time to sufficiently remove residues such as resin and conductive filler on the wiring substrate. On the other hand, in a state where a certain amount of residue remains on the wiring substrate, There is a problem that conductivity can not be ensured when the connection of the electronic parts is intended. As described above, the anisotropic conductive material described in Document 1 has a certain degree of repairability, but is not necessarily at a sufficient level. Further, in the case of using the anisotropic conductive material described in the above-mentioned document 1, there is a problem in terms of connection reliability, in order to ensure the connection reliability of the connection portion, that gold-plating treatment is required for the electrodes of the electronic parts to be connected and the wiring board .
Therefore, an object of the present invention is to provide an anisotropic conductive paste having sufficient repairability and high connection reliability, and a connection method of an electronic part using the anisotropic conductive paste.
The anisotropic conductive paste of the present invention is an anisotropic conductive paste for connecting electronic components and a wiring board, wherein the anisotropic conductive paste contains 10% by mass or more and 50% by mass or less of a lead-free solder powder having a melting point of 240 占 폚 or less and a thermosetting resin and an organic acid Wherein the thermosetting resin composition has an acid value of 15 mgKOH / g or more and 55 mgKOH / g or less, wherein the thermosetting resin composition contains 50% by mass or more and 90% by mass or less of the thermosetting resin composition.
In the anisotropic conductive paste of the present invention, it is preferable that the thermosetting resin is an epoxy resin, and the organic acid is a dibasic acid having an alkylene group.
In the anisotropic conductive paste of the present invention, the thermosetting resin composition preferably further contains a thixotropic agent, and the content of the inorganic anticorrosive in the thixotropic agent is preferably 0.5% by mass or more and 22% by mass or less.
In the anisotropic conductive paste of the present invention, it is preferable that the average particle diameter of the lead-free solder powder is 1 mu m or more and 34 mu m or less.
In the anisotropic conductive paste of the present invention, it is preferable that the lead-free solder powder includes at least one kind of metal selected from the group consisting of tin, copper, silver, bismuth, antimony, indium and zinc.
In the anisotropic conductive paste of the present invention, it is preferable that at least one of the electrode of the electronic component and the electrode of the wiring substrate is not subjected to the gold plating treatment.
According to the present invention, there is also provided a method of connecting an electronic component using the anisotropic conductive paste, the method comprising: a coating step of applying the anisotropic conductive paste on the wiring board; and a step of disposing the electronic component on the anisotropic conductive paste And a thermocompression bonding step of thermocompression bonding the electronic component to the wiring board at a temperature higher than the melting point of the lead-free solder powder by 5 ° C or more.
In the electronic component connecting method of the present invention, it is preferable that the method further comprises: a peeling step of peeling the electronic component from the wiring board at a temperature higher than the melting point of the lead-free solder powder by 5 ° C or more; and applying the anisotropic conductive paste onto the wiring board after the peeling step And a reheating step of disposing the electronic component on the anisotropic conductive paste after the reapplication process and thermally pressing the electronic component to the wiring board at a temperature higher than the melting point of the leadless solder powder by 5 ° C or more .
In the present invention, the anisotropic conductive paste means anisotropic conductive paste having conductivity in the direction of thermal compression bonding (thickness direction) at a position where a heat of a predetermined value or higher and a pressure higher than a predetermined value are applied, Refers to a paste capable of forming ashes.
The reason why the anisotropic conductive paste of the present invention has sufficient repairability and mechanical strength as well as high connection reliability is not necessarily clear, but the present inventors contemplate as follows.
That is, unlike the conventional anisotropic conductive material, the anisotropic conductive paste of the present invention contains a lead-free solder powder. When the anisotropic conductive paste is thermally bonded at a temperature not lower than the melting point of the lead-free solder powder, the lead-free solder powder is melted and brought close to each other, and the lead-free solder around the lead-free solder is increased. On the other hand, since the distance between the electrodes of the electronic component and the wiring board is shortened by thermocompression bonding, the electrodes can be soldered to each other by the lead-free solder enlarged as described above. As described above, in the present invention, since the electrodes of the electronic component and the wiring board are soldered to each other, as compared with the conventional anisotropic conductive material in which the electrodes and the conductive fillers are connected to each other by contact with each other, The inventors insist.
On the other hand, as described above, there is no possibility of solder bonding to the portions (the gaps between the electrodes of the electronic components and the gaps between the electrodes of the wiring board) that are not subjected to thermocompression at a pressure of a predetermined value or higher and a pressure of a predetermined value or more, The lead-free solder powder is buried in the resin composition. Therefore, the insulating property is ensured for a portion not subjected to thermocompression at a heat of a predetermined value or higher and a pressure of a predetermined value or higher.
When the electronic component and the wiring board are connected to the anisotropic conductive paste of the present invention, it is presumed that the electrodes of the electronic component and the wiring board are soldered to each other as described above, and the solder joint portion is covered with the thermosetting resin composition. When the heat is applied at a temperature equal to or higher than the melting point of the lead-free solder powder after thermocompression bonding, the solder can be melted and the thermosetting resin composition can be softened. In addition, in the present invention, even if a residue (solder or the like) remains to some extent on the electrode when the wiring board and the electronic component are connected using the anisotropic conductive paste after peeling, the residue can be soldered together Conductivity can be ensured. On the other hand, in the case of the conventional anisotropic conductive material, conductivity can not be ensured when the electronic parts are connected again by using an anisotropic conductive material in a state where a certain amount of residue (conductive filler or the like) remains on the wiring substrate . Therefore, it is necessary to sufficiently remove residues such as resin and conductive filler on the wiring board, and there is a problem that it takes time to perform the operation. As described above, the anisotropic conductive paste of the present invention is excellent in repairability as compared with the conventional anisotropic conductive material.
In the present invention, the part of the solder joint is covered with the thermosetting resin composition, and the part of the solder joint can be reinforced because the thermosetting resin composition is cured by heat. Therefore, when the electronic component and the wiring board are connected to the anisotropic conductive paste of the present invention, sufficient mechanical strength can be ensured.
According to the present invention, it is possible to provide an anisotropic conductive paste having sufficient repairability and high connection reliability, and a connection method of an electronic part using the anisotropic conductive paste.
First, the anisotropic conductive paste of the present invention will be described.
The anisotropic conductive paste of the present invention is an anisotropic conductive paste for connecting an electronic component and a wiring board. The anisotropic conductive paste contains 10% by mass or more and 50% by mass or less of the lead-free solder powder described below, and 50% by mass or more and 90% by mass or less of the thermosetting resin composition described below.
When the content of the lead-free solder powder is less than 10% by mass (when the content of the thermosetting resin composition exceeds 90% by mass), sufficient solder bonding is formed between the electronic component and the wiring board when the resulting anisotropic conductive paste is thermally bonded , The conductivity between the electronic component and the wiring board becomes insufficient. On the other hand, when the content of the lead-free solder powder is more than 50% by mass (when the content of the thermosetting resin composition is less than 50% by mass), the resulting anisotropic conductive paste The insulating property in the case of being left in a humidified state becomes insufficient, and as a result, the anisotropy is not exhibited by the solder bridge. The content of the lead-free solder powder is preferably 20% by mass or more and 45% by mass or less, more preferably 30% by mass or more and 40% by mass or less from the viewpoint of achieving balance between the insulating property and the conductivity in the case of thermocompression bonding in the resultant anisotropic conductive paste Is more preferable.
The lead-free solder powder used in the present invention has a melting point of 240 캜 or lower. When this lead-free solder powder having a melting point exceeding 240 캜 is used, the lead-free solder powder can not be melted at a normal hot-pressing temperature in the anisotropic conductive paste. From the viewpoint of lowering the thermal compression temperature in the anisotropic conductive paste, the melting point of the lead-free solder powder is preferably 220 占 폚 or lower, more preferably 150 占 폚 or lower.
Here, the lead-free solder powder refers to a solder metal or an alloy powder to which lead is not added. However, the presence of lead as an unavoidable impurity in the lead-free solder powder is allowed, but in this case, the amount of lead is preferably 100 mass ppm or less.
The lead-free solder powder is at least one kind of metal selected from the group consisting of tin (Sn), copper (Cu), silver (Ag), bismuth (Bi), antimony (Sb), indium (In) .
Specific examples of the solder composition (mass ratio) in the lead-free solder powder are as follows.
Examples of the binary alloy include Ag-Bi based materials such as 95.3 Ag / 4.7 Bi and Ag-Li based materials such as 66 Ag / 34 Li and Ag-In based materials such as 3Ag / Ag based alloys such as Ag-Ti based materials such as Ag-Ti based materials and Ag based materials such as Ag-Ti based materials such as Bi-In and Bi-In based alloys; Au-Sn based materials such as 80Au / 20Sn; Bi-In based materials such as 52.7Bi / 47.3In; Sn-Bi based materials such as 43Sn / 57Bi and 42Sn / 58Bi, 98Sn / 2Ag, 96.5Sn / 3.5Ag and Sn-Bi based materials such as In-Sn based materials such as 51In / 49Sn and 52In / 48Sn, Bi- A Sn-Ag-based alloy such as 99Sn / 0.7Cu, a Sn-Sb-based alloy such as 95Sn / 5Sb, .
Examples of the ternary alloy include Sn-Ag-In such as 95.5Sn / 3.5Ag / 1In, Sn-Zn-In such as 86Sn / 9Zn / 5In and 81Sn / 9Zn / 10In, 95.5Sn / 0.5Ag / Sn-Bi-Ag type such as Sn-Ag-Cu type, 90.5Sn / 7.5Bi / 2Ag and 41.0Sn / 58Bi / 1.0Ag, etc., 89.0Sn / 8.0Zn / 3.0 And Sn-Zn-Bi system such as Bi.
Other alloys include Sn / Ag / Cu / Bi systems and the like.
The average particle diameter of the lead-free solder powder is preferably 1 mu m or more and 34 mu m or less, more preferably 3 mu m or more and 20 mu m or less. If the mean particle diameter of the lead-free solder powder is less than the above lower limit, the conductivity between the electronic component and the wiring board tends to decrease. On the other hand, if the above-mentioned upper limit is exceeded, the insulating property in the anisotropic conductive paste tends to decrease. The average particle diameter can be measured by a dynamic light scattering particle size measuring apparatus.
The thermosetting resin composition used in the present invention contains a thermosetting resin and an organic acid. The acid value of the thermosetting resin composition is required to be 15 mgKOH / g or more and 55 mgKOH / g or less. When the acid value is less than 15 mgKOH / g, the solder can not sufficiently be activated when the resulting anisotropic conductive paste is thermally pressed, resulting in insufficient conductivity between the electronic component and the wiring board. On the other hand, when the anisotropic conductive paste exceeds 55 mgKOH / g, The insulating property in the case of being left in a humidified state becomes insufficient. The acid value of the thermosetting resin composition is preferably 20 mgKOH / g or more and 50 mgKOH / g or less, more preferably 30 mgKOH / g or more and 45 mgKOH / g or less, from the viewpoint that the resultant anisotropic conductive paste has a balance of insulation property and conductivity in the case of thermocompression bonding. g or less.
As the thermosetting resin to be used in the present invention, a known thermosetting resin can be suitably used, but an epoxy resin is particularly preferably used from the viewpoint of having a flux action.
In addition, in the present invention, those having a flux action include a rosin-based flux that covers the metal surface of the brazed body to block the atmosphere, reduces the metal oxide on the metal surface during soldering, The film is pushed into the molten solder so that the molten solder can be brought into contact with the metal surface, and the residue has a function of insulating the circuits.
As such an epoxy resin, a known epoxy resin can be appropriately used. Examples of such epoxy resins include epoxy resins such as bisphenol A type, bisphenol F type, biphenyl type, naphthalene type, cresol novolak type, phenol novolac type and dicyclopentadiene type. These epoxy resins may be used singly or in combination of two or more kinds. It is preferable that these epoxy resins contain liquid ones at room temperature. When solid resins are used at room temperature, they are preferably used in combination with liquid ones at room temperature. From the viewpoints of being able to adjust the dispersibility and paste viscosity of the metal particles among the forms of these epoxy resins and to improve the resistance to falling impact of the cured product, from the viewpoint of good wettability of the solder, A bisphenol A type, a liquid bisphenol F type, a liquid hydrogenated type bisphenol A type, a naphthalene type, and a dicyclopentadiene type are preferable. From the viewpoint of storage stability of the resulting anisotropic conductive paste, it is preferable to use the combination of liquid bisphenol A type and liquid bisphenol F type.
The content of the epoxy resin is preferably 70 mass% or more and 92 mass% or less, more preferably 75 mass% or more and 85 mass% or less, based on 100 mass% of the thermosetting resin composition. If the content of the epoxy resin is less than the above lower limit, resistance to drop impact tends to decrease since sufficient strength is not obtained for fixing the electronic component. On the other hand, if the content exceeds the upper limit, the content of the organic acid and the curing agent in the thermosetting resin composition And the speed of curing the epoxy resin tends to be delayed.
As the organic acid to be used in the present invention, a known organic acid may be suitably used. Of these organic acids, it is preferable to use a dibasic acid having an alkylene group from the viewpoints of excellent solubility with epoxy resins and from the viewpoint that precipitation of crystals hardly occurs during storage. Examples of the dibasic acid having an alkylene group include adipic acid, 2,5-diethyladipic acid, glutaric acid, 2,4-diethylglutaric acid, 2,2-diethylglutaric acid , 3-methylglutaric acid, 2-ethyl-3-propylglutaric acid, sebacic acid, succinic acid, malonic acid and diglycolic acid. Of these, adipic acid, glutaric acid and succinic acid are preferable, and adipic acid is particularly preferable.
The content of the organic acid is preferably 1% by mass or more and 8% by mass or more, more preferably 2% by mass or more and 7% by mass or less based on 100% by mass of the thermosetting resin composition. If the content of the organic acid is less than the above lower limit, the speed of curing the thermosetting resin such as an epoxy resin tends to be retarded, and the curing tends to become defective. On the other hand, when the content exceeds the upper limit, the insulating property in the obtained anisotropic conductive paste tends to decrease .
The thermosetting resin composition used in the present invention is preferably a thermosetting resin and a curing agent other than the thermosetting resin and the organic acid.
As the chit agent used in the present invention, a known chit agent can be appropriately used. Examples of such a tin agent include organic tin agents (fatty acid amide, hydrogenated castor oil, olefin wax, etc.) and inorganic anticorrosives (colloidal silica, benton, etc.). Of these, fatty acid amides, colloidal silica and benton are preferred. From the viewpoint of difficulty in spreading the obtained anisotropic conductive paste, it is preferable to use it in combination with an organic antistatic agent and an inorganic antistatic agent. Specific examples include a combination of fatty acid amide and colloidal silica, and a combination of fatty acid amide and benthone.
The content of the thixotropic agent is preferably 0.5 mass% or more and 25 mass% or less, more preferably 0.5 mass% or more and 10 mass% or less, and particularly preferably 1 mass% or more and 5 mass% or less, relative to 100 mass% of the thermosetting resin composition Do. If the content of the tick scouring agent is less than the above lower limit, the tack can not be obtained and sagging easily occurs on the electrode of the wiring substrate, so that the adhesive force when the electronic component is mounted on the electrode of the wiring substrate tends to decrease, On the other hand, if the upper limit is exceeded, the thermosetting is excessively high, and the syringe needle tends to become clogged so that coating failure tends to occur.
When used in combination with the organic-based anticorrosive agent and the inorganic-based anticorrosion agent as the tin agent for use in the present invention, the content of the inorganic-based anticorrosive agent is preferably 0.5% by mass or more and 22% by mass or less based on 100% by mass of the thermosetting resin composition , And more preferably 1 mass% or more and 20 mass% or less.
As the curing agent for use in the present invention, a suitable known curing agent can be used. For example, when an epoxy resin is used as the thermosetting resin, the following can be used.
Examples of the latent curing agent include Novacure HX-3722, HX-3721, HX-3748, HX-3088, HX-3613, HX-3921HP and HX-3941HP (trade name, product of Asahi Kasei Epoxy Co., Ltd.).
Examples of the aliphatic polyamine curing agent include Fuji Cure FXR-1020, FXR-1030, FXR-1050, and FXR-1080 (trade names, manufactured by Fuji Kasei Kogyo Co., Ltd.).
Examples of the epoxy resin amine adduct type curing agent include Amicure PN-23, PN-F, MY-24, VDH, UDH, PN-31 and PN-40 (trade names, manufactured by Ajinomoto Fine Techno Co., EH-3636AS, EH-4346S (trade name, product of Asahi Denka Kogyo Co., Ltd.).
Examples of the imidazole-based curing accelerators include 2P4MHZ, 2MZA, 2PZ, C11Z, C17Z, 2E4MZ, 2P4MZ, C11Z-CNS and 2PZ-CNZ (trade names).
These curing agents are preferably used in combination of the latent curing agent, the epoxy resin amine adduct curing agent and the imidazole type curing accelerator from the viewpoint of the insulating property of the resulting anisotropic conductive paste.
The content of the curing agent is preferably 5 mass% or more and 20 mass% or less, more preferably 10 mass% or more and 18 mass% or less, relative to 100 mass% of the thermosetting resin composition. If the content of the curing agent is less than the above lower limit, the curing speed of the thermosetting resin tends to be delayed. On the other hand, when the content exceeds the upper limit, the reactivity tends to be shortened.
The thermosetting resin composition used in the present invention may contain additives such as a surfactant, a coupling agent, a defoaming agent, a powder surface treatment agent, a reaction inhibitor, and an anti-settling agent in addition to the epoxy resin, the organic acid, good. The content of these additives is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less based on 100% by mass of the thermosetting resin composition. When the content of the additive is less than the above lower limit, the effect of each additive tends to be hardly exhibited. On the other hand, if the content exceeds the upper limit, the bonding strength by the thermosetting resin composition tends to decrease.
Next, a connection method of the electronic component of the present invention will be described.
A method for connecting an electronic component of the present invention is a method for connecting an electronic component using the anisotropic conductive paste of the present invention described above, comprising the steps of: applying the anisotropic conductive paste onto the wiring board; And a thermocompression bonding step of thermocompression bonding the electronic component to the wiring board at a temperature higher than the melting point of the lead-free solder powder by 5 ° C or more (preferably 20 ° C or more).
Here, as the electronic component, a wiring board other than a chip, a package component, and the like may be used. As the wiring substrate, a flexible substrate having flexibility and a rigid substrate having no flexibility can be used. In addition, when a flexible substrate is used as an electronic component, the rigid boards can be electrically connected to each other through a flexible substrate by connecting them to two wiring boards (rigid boards). The flexible substrates may be electrically connected to each other through a flexible substrate.
In the application step, the anisotropic conductive paste is applied onto the wiring board.
Examples of the coating apparatus used here include a dispenser, a screen printing machine, and a jet dispensing metal mask printing machine.
The thickness of the coating film is not particularly limited, but is preferably from 50 탆 to 500 탆, and more preferably from 100 탆 to 300 탆. If the thickness is less than the lower limit described above, there is a tendency that the adhesive force when the electronic component is mounted on the electrode of the wiring board tends to decrease. On the other hand, when the upper limit is exceeded, the paste tends to be pushed out in addition to the connection portion. In the thermocompression bonding process, the electronic component is placed on the anisotropic conductive paste, and the electronic component is thermally bonded to the wiring board at a temperature higher than the melting point of the lead-free solder powder by 5 ° C or more.
The lead-free solder can not be sufficiently melted and the sufficient solder joint can not be formed between the electronic component and the wiring board when the condition that the temperature at the time of thermocompression is higher than the melting point of the lead-free solder powder by 5 DEG C or more is not satisfied, The conductivity between the component and the wiring substrate becomes insufficient.
The pressure at the time of thermocompression bonding is not particularly limited, but is preferably 0.2 Mpa or more and 2 Mpa or less, more preferably 0.5 Mpa or more and 1.5 Mpa or less. If the pressure is less than the above lower limit, sufficient solder bonding can not be formed between the electronic component and the wiring substrate, and the conductivity between the electronic component and the wiring substrate tends to decrease. On the other hand, stress is applied to the wiring substrate exceeding the upper limit, And the like.
Further, in the present invention, as described above, the pressure at the time of thermocompression bonding can be set to a lower pressure range as compared with the case of the conventional method. Therefore, the cost of the apparatus used in the thermocompression bonding process can be reduced.
The time for thermocompression bonding is not particularly limited, but is usually from 5 seconds to 60 seconds, preferably from 7 seconds to 20 seconds.
In the electronic component connecting method of the present invention, it is preferable to further include a peeling process, a reapplication process, and a reheat bonding process, which will be described below.
In the peeling step, the electronic component is peeled from the wiring board at a temperature higher than the melting point of the lead-free solder powder by 5 캜 or more.
Here, the method of peeling the electronic component from the wiring substrate is not particularly limited. As such a method, for example, a method of peeling the electronic component from the wiring board while heating the connection portion by using soldering iron or the like can be employed. In this case, a known peeling apparatus used for repair may be used.
Further, after the electronic component is peeled from the wiring substrate, the wiring substrate may be cleaned with a solvent or the like, if necessary.
In the reapplication step, the anisotropic conductive paste is applied onto the wiring board after the peeling step. Here, the thickness of the application device or the coating film is the same as the above-mentioned coating process, but conditions can be adopted.
In the reheating step, the electronic component is disposed on the anisotropic conductive paste after the reapplication step, and the electronic component is thermally bonded to the wiring board at a temperature higher by 5 ° C or more than the melting point of the lead-free solder powder. The temperature, pressure and time at the time of thermocompression bonding may be the same as those in the above-mentioned application step.
According to the connection method of the electronic component of the present invention described above, since the electrodes of the electronic component and the wiring board are solder-bonded to each other, the electrode and the conductive filler, as in the case of the conventional anisotropic conductive material, Connection reliability can be achieved. Further, when heat at a temperature higher than the melting point of the lead-free solder powder is applied after thermocompression bonding, the solder can be melted and the thermosetting resin composition can be softened, so that the electronic component can be easily peeled from the wiring board. In addition, in the present invention, even if a residue (solder or the like) remains to some extent on the electrode when the wiring board and the electronic component are connected using the anisotropic conductive paste after peeling, the residue can be soldered together Conductivity can be ensured. Therefore, the connection method of the electronic component of the present invention is excellent in the repairing property as compared with the conventional method using the anisotropic conductive material.
[Example]
EXAMPLES Next, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples at all.
[Example 1]
, 82.9% by mass of a thermosetting resin A (bisphenol A type epoxy resin, product name of EPICLON 860, manufactured by DLC Corporation), 2% by mass of a tincture A (fatty acid amide, manufactured by Nippon Kayasei Co., , 0.5% by mass of a surfactant (trade name " BYK361N " manufactured by Big Chemical Japan Co., Ltd.) and 2.6% by mass of a curing agent A (manufactured by Shikoku Chemical Industry Co., Ltd., trade name " Kyouzol 2P4MHZ " 0.5% by mass of an antifoaming agent (trade name: Flowen AC-326F, manufactured by Kyoeisha Chemical Co., Ltd.) was put into a container and mixed using Raikai mixers to obtain a thermosetting resin composition.
Thereafter, 37.5 mass% of the obtained thermosetting resin composition and 62.5 mass% of lead-free solder powder A (average particle diameter: 5 탆, melting point of solder: 139 캜, composition of solder: 42 Sn / 58 Bi) For 2 hours to prepare an anisotropic conductive paste.
Subsequently, the obtained anisotropic conductive paste was applied (thickness: 0.2 mm) on a wiring board (electrode: copper electrode with gold plating (Cu / Ni / Au)). Then, an electronic component (electrode: gold-plated (Cu / Ni / Au) on the copper electrode) was placed on the anisotropic conductive paste after the application and the temperature was 200 ° C, The electronic parts were thermally bonded to the wiring board under the conditions of a compression time of 8 to 10 seconds.
[Example 2]
Electronic parts were thermocompression-bonded to a wiring board in the same manner as in Example 1, except that an electrode was used as the wiring board and the copper electrode was subjected to a water-soluble pre-flux treatment (trade name: WPF-8, manufactured by Tamura Corporation).
[Example 3]
An electronic part was thermally bonded to a wiring board in the same manner as in Example 2 except that the electrode was made of tin (Sn).
[Example 4]
A thermosetting resin composition and an anisotropic conductive paste were obtained in the same manner as in Example 1 except that each material was blended according to the composition shown in Table 1.
Electronic parts were thermally bonded to the wiring board in the same manner as in Example 2 except that the anisotropic conductive paste obtained as described above was used in place of the anisotropic conductive paste used in Example 2. [
[Example 5]
A thermosetting resin composition and an anisotropic conductive paste were obtained in the same manner as in Example 1 except that each material was blended according to the composition shown in Table 1.
In Example 5, lead-free solder powder B (average particle size: 5 탆, solder melting point: 217 캜, solder composition: 96.5Sn / 3Ag / 0.5Cu) is used.
The electronic component was heated to the wiring board in the same manner as in Example 2 except that the anisotropic conductive paste obtained as described above was used in place of the anisotropic conductive paste used in Example 2 and the temperature at the time of thermocompression bonding was changed to 240 캜 Squeezed.
[Comparative Examples 1 to 4]
A thermosetting resin composition and an anisotropic conductive paste were obtained in the same manner as in Example 1 except that each material was blended according to the composition shown in Table 1.
Electronic parts were thermally bonded to the wiring board in the same manner as in Example 2 except that the anisotropic conductive paste obtained as described above was used in place of the anisotropic conductive paste used in Example 2. [
[Comparative Example 5]
A thermosetting resin composition and an anisotropic conductive paste were obtained in the same manner as in Example 1 except that each material was blended according to the composition shown in Table 1.
In Comparative Example 5, a resin powder (Au / Ni plating resin powder, manufactured by Sekisui Chemical Co., Ltd., trade name "Micro Pearl Au-205") subjected to a gold plating treatment is used.
The electronic parts were thermally bonded to the wiring board in the same manner as in Example 1 except that the anisotropic conductive paste obtained as described above was used in place of the anisotropic conductive paste used in Example 1.
[Comparative Example 6]
Electronic parts were thermally bonded to a wiring board in the same manner as in Comparative Example 5 except that an electrode was used as the wiring board and the copper electrode was subjected to a water-soluble pre-flux treatment (trade name: WPF-8, manufactured by Tamura Seisakusho Co., Ltd.).
[Comparative Example 7]
An electronic component was thermally bonded to a wiring board in the same manner as in Comparative Example 5 except that the electrode was made of tin (Sn).
<Evaluation of connection method of anisotropic conductive paste and electronic component>
(Initial resistance value after pressing, repellency (presence or absence of substrate breakage at the time of repair, resistance value after repair)) of the anisotropic conductive paste (the acid value of the resin composition, the insulation resistance value after compression and the connection method of the electronic component) Were evaluated or measured in the following manner. The obtained results are shown in Tables 1 and 2. In Comparative Examples 6 to 7, since the initial resistance value after compression was not measurable due to inability to conduct, the repairability was not evaluated.
(1) The acid value of the resin composition
The resin composition is weighed and dissolved in a solvent. The phenolphthalein solution was used as an indicator and titrated with 0.5 mol / L KOH.
(2) Initial resistance value after crimping
A wiring board having a 0.2 mm pitch land (line / space = 100 mu m / 100 mu m) was prepared as a circuit pattern. Then, an electronic component having 0.2 mm pitch land (line / space = 100 mu m / 100 mu m) was thermally bonded onto the land of the wiring board by the method described in the above Examples and Comparative Examples. Then, the resistance value between the terminals of lands connected by using a digital multimeter (product name "34401A" manufactured by Agilent Co., Ltd.) was measured. In addition, when the resistance value was too high (100 M? Or more) and conduction could not be carried out, it was judged that "conduction was impossible".
(3) Presence or absence of substrate destruction during repair
The evaluation is made using a substrate on which the initial resistance value is measured in the above (2). The electronic parts were peeled from the substrate while heating the connection part of the electronic parts of the substrate to a temperature equal to the thermocompression bonding temperature, and then the surface contamination was cleaned with ethyl acetate. Then, the state of the substrate after peeling was observed with naked eyes to investigate whether there was substrate breakage.
(4) Resistance value after repair
In the above (3), the substrate is evaluated for the presence or absence of substrate breakage. The electronic parts were again thermally pressed onto the lands of the substrate by the methods described in the above-described Examples and Comparative Examples. Then, the resistance value between the terminals of lands connected by using a digital multimeter (product name "34401A" manufactured by Agilent Co., Ltd.) was measured. In addition, when the resistance value was too high (100 M? Or more) and conduction could not be carried out, it was judged that "conduction was impossible".
(5) Insulation resistance value after compression
The anisotropic conductive pastes obtained in Examples and Comparative Examples were printed on copper foil lands of a comb-shaped electrode substrate (glass epoxy resin substrate) having a pitch of 0.2 mm (line / space = 100 占 퐉 / 100 占 퐉) And a test piece was obtained by heating at 240 占 폚 in a reflow furnace (trade name "TNP" manufactured by TAMURA SEISAKUSHO Co., Ltd.). The test piece was subjected to a voltage of 15 V at 85 캜 and 85% RH (relative humidity) to measure the insulation resistance value after 168 hours.
As apparent from the results shown in Tables 1 and 2, when the wiring board and the electronic component are connected using the anisotropic conductive paste of the present invention (Examples 1 to 5), sufficient repairability and high connection reliability can be ensured .
On the other hand, in the case where the blending amount of the lead-free solder powder in the anisotropic conductive paste is 5% by mass (Comparative Example 1) and the acid value of the resin composition in the anisotropic conductive paste is 5 mgKOH / g (Comparative Example 3) It was confirmed that the conductivity of the wiring board and the electronic component can not be ensured.
When the blending amount of the lead-free solder powder in the anisotropic conductive paste is 60 mass% (Comparative Example 2) and the acid value of the resin composition in the anisotropic conductive paste is 70 mg KOH / g (Comparative Example 4) It was confirmed that the insulating property to the portion where the thermocompression bonding does not occur can not be ensured.
In the case of using the anisotropic conductive paste containing no solder powder (Comparative Examples 5 to 7), as long as the gold plating process was not performed on both the electrodes of the wiring board and the electrodes of the electronic component, I could not even do it. It was also confirmed that the gold plating treatment (Comparative Example 5) on both the electrode of the wiring board and the electrode of the electronic component was not conducted after the repair and the repairability was poor.
[Examples 6 to 17]
A thermosetting resin composition and an anisotropic conductive paste were obtained in the same manner as in Example 1 except that each material was blended according to the compositions shown in Tables 3 and 4.
The electronic parts were thermally bonded to the wiring board in the same manner as in Example 1 except that the anisotropic conductive paste obtained as described above was used in place of the anisotropic conductive paste used in Example 1.
The materials used in Examples 6 to 17 are shown below.
Thermosetting resin A: bisphenol A type epoxy resin, trade name "EPICLON 860", manufactured by DIC
Thermosetting resin B: bisphenol F type epoxy resin, trade name " EPICLON 830CRP ", manufactured by DIC
Thermosetting resin C: Mixed epoxy resin of bisphenol A type and bisphenol F type, trade name " EPICLON EXA-830LVP ", manufactured by DIC
Thermosetting resin D: dicyclopentadiene type epoxy resin, trade name " EPICLON HP-7200H ", manufactured by DIC
Thermosetting resin E: naphthalene type epoxy resin, trade name "EPICLON HP-4032D", manufactured by DIC
Ticks A: Fatty acid amide, manufactured by Nippon Kayasei Co., Ltd., trade name " Sripax H "
Ticks agent B: colloidal silica, trade name " AEROSIL R974 ", Nippon Aerosilicate
Thick cleaner C: manufactured by Benton, Wilbur-ellis Co., Ltd.
Organic acid A: Adipic acid, manufactured by Kanto Denka Kogyo Co., Ltd.
Organic acid B: glutaric acid, manufactured by Tokyo Kasei High School
Organic acid C: succinic acid, manufactured by Mitsubishi Chemical Corporation
Curing agent A: Imidazole-based curing accelerator, trade name " Cueazole 2P4M HZ ", manufactured by Shikoku Chemicals
Curing agent B: Imidazole-based curing accelerator, trade name " Cueazole 2MZA-PW ", manufactured by Shikoku Chemicals
Curing agent C: Epoxy resin amine adduct type curing agent, " Amicure PN-F ", Ajinomoto Fine Techno Co.,
Curing agent D: Latent curing agent, trade name " NOVACURE HX-3721 ", manufactured by Asahi Kasei Epoxy Co.,
Surfactant: trade name " BYK361N ", manufactured by Big Chemie Japan
Antifoaming agent: trade name "Flowen AC-326F", manufactured by Kyoeisha Kagaku Co.,
Lead-free solder powder A: average particle diameter: 5 탆, melting point of solder: 139 캜, composition of solder: 42 Sn / 58 Bi
Pb-free solder powder B: average particle diameter: 5 占 퐉, melting point of solder: 217 占 폚, composition of solder: 96.5Sn / 3Ag / 0.5Cu
<Evaluation of connection method of anisotropic conductive paste and electronic component>
(The acid value of the resin composition, the insulation resistance after compression, and the storage stability) of the anisotropic conductive paste and the evaluation of the connection method of the electronic components (initial resistance value after compression, repairability Presence or absence of substrate breakage at the time of repair, resistance value after repair, and bridge observation by X-ray) were evaluated or measured by the above method and the following method. The obtained results are shown in Tables 3 and 4.
(6) Bridge observation by X-ray
The presence or absence of bridges and the spread of the anisotropic conductive paste were judged based on the following criteria by using a microfocus X-ray fluoroscopic apparatus (manufactured by SHI-MADZU: SMX-160E) Also, a bridge is an unexpected short circuit between adjacent terminals.
A: No bridge, no anisotropic conductive paste.
B: There is no bridge, but there is a slight smearing of the anisotropic conductive paste.
C: There is a bridge.
(7) Storage stability
The viscosity of the anisotropic conductive paste after storage at 10 ° C was measured and the time when the rate of change with respect to the initial value did not exceed ± 20% was measured. The viscosity was measured by using a viscometer (PCU-205 made by Matsuko Chemical Co., Ltd.) in a plastic container adjusted to 25 DEG C in a thermostatic chamber.
The following points were confirmed from the results shown in Tables 3 and 4.
From the results of Examples 1 and 6, it was confirmed that the anisotropic conductive paste hardly spreads when used as a combination of an organic-based thickener and an inorganic-based thickener as a tick agent.
From the results of Examples 6 and 7, it was confirmed that when the latent curing agent and the epoxy resin amine adduct curing agent as the curing agent and the imidazole curing accelerator were used in combination, the insulation resistance value after compression was improved.
From the results of Examples 7, 8 and 12 to 14, it was confirmed that the storage stability of the anisotropic conductive paste was improved when the epoxy resin was used in combination of liquid bisphenol A type and liquid bisphenol F type.
From the results of Examples 8, 15 and 16, it was confirmed that it is preferable to use dibasic acid having an alkylene group as an organic acid. In particular, it was confirmed that the use of adipic acid as the organic acid (Example 8) tended to lower the initial resistance value after compression and the resistance value after repair.
Claims (8)
Wherein the anisotropic conductive paste contains a lead-free solder powder having a melting point of 240 DEG C or less, and a thermosetting resin composition,
The content of the lead-free solder powder is 10% by mass or more and 50% by mass or less based on 100% by mass of the anisotropic conductive paste,
The content of the thermosetting resin composition is 50% by mass or more and 90% by mass or less based on 100% by mass of the anisotropic conductive paste,
The thermosetting resin composition contains a thermosetting resin, an organic acid, and a tin agent,
Wherein the thixotropic agent comprises an organic-based chitosan and an inorganic chitosan,
Wherein the acid value of the thermosetting resin composition is 15 mgKOH / g or more and 55 mgKOH / g or less.
The thermosetting resin is an epoxy resin,
Wherein the organic acid is a dibasic acid having an alkylene group.
Wherein the content of the inorganic thixotropic agent is 0.5% by mass or more and 22% by mass or less based on 100% by mass of the thermosetting resin composition.
Wherein an average particle diameter of the lead-free solder powder is 1 占 퐉 or more and 34 占 퐉 or less.
Wherein the lead-free solder powder comprises at least one metal selected from the group consisting of tin, copper, silver, bismuth, antimony, indium and zinc.
An application step of applying the anisotropic conductive paste onto the wiring board;
And a thermocompression bonding step of placing the electronic component on the anisotropic conductive paste and thermally bonding the electronic component to the wiring board at a temperature higher than the melting point of the leadless solder powder by 5 ° C or more. Connection method.
A peeling step of peeling the electronic component from the wiring board at a temperature higher than the melting point of the lead-free solder powder by 5 DEG C or more;
A re-coating step of applying the anisotropic conductive paste onto the wiring board after the peeling step,
And a reheating step of disposing the electronic component on the anisotropic conductive paste after the reapplication process and thermally pressing the electronic component to the wiring board at a temperature higher than the melting point of the leadless solder powder by 5 ° C or more Of the electronic component.
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| JPJP-P-2011-074433 | 2011-03-30 | ||
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| JP2012008330A JP5964597B2 (en) | 2011-03-30 | 2012-01-18 | Anisotropic conductive paste and method of connecting electronic parts using the same |
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| CN104822773B (en) * | 2013-05-23 | 2017-09-22 | 积水化学工业株式会社 | Conductive material and connection structural bodies |
| CN105493201B (en) * | 2014-02-24 | 2018-12-07 | 积水化学工业株式会社 | The manufacturing method of conductive paste, connection structural bodies and connection structural bodies |
| KR102360487B1 (en) * | 2014-02-24 | 2022-02-10 | 세키스이가가쿠 고교가부시키가이샤 | Connection structure manufacturing method |
| JP2016088978A (en) * | 2014-10-31 | 2016-05-23 | 京セラケミカル株式会社 | Conductive resin composition and electronic component device using the same |
| KR20170038691A (en) | 2015-09-30 | 2017-04-07 | 다이요 잉키 세이조 가부시키가이샤 | Conductive adhesive and method for production thereof, cured product, and electronic component |
| JP2017069543A (en) | 2015-09-30 | 2017-04-06 | 太陽インキ製造株式会社 | Connection structure and electronic component |
| JP6710120B2 (en) | 2015-09-30 | 2020-06-17 | 太陽インキ製造株式会社 | Conductive adhesive, electronic component, and method for manufacturing electronic component |
| JP2017203109A (en) * | 2016-05-11 | 2017-11-16 | パナソニックＩｐマネジメント株式会社 | Resin composition containing conductive particle and electronic device including the resin composition |
| JP6899275B2 (en) * | 2016-08-10 | 2021-07-07 | Ｄｏｗａエレクトロニクス株式会社 | Silver alloy powder and its manufacturing method |
| JP2018131569A (en) * | 2017-02-16 | 2018-08-23 | パナソニックＩｐマネジメント株式会社 | Resin composition comprising conductive particles |
| TWI761477B (en) | 2017-03-30 | 2022-04-21 | 日商太陽油墨製造股份有限公司 | Conductive adhesive, cured product, electronic component, and manufacturing method of electronic component |
| JP2020075995A (en) * | 2018-11-07 | 2020-05-21 | パナソニックＩｐマネジメント株式会社 | Curable resin composition and mounting structure |
| WO2020255874A1 (en) * | 2019-06-20 | 2020-12-24 | 積水化学工業株式会社 | Electroconductive material, connection structure, and method for manufacturing connection structure |
| JP7425561B2 (en) * | 2019-08-09 | 2024-01-31 | 積水化学工業株式会社 | Conductive material, connected structure, and method for manufacturing connected structure |
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| JP2003049145A (en) | 2001-08-06 | 2003-02-21 | Tomoegawa Paper Co Ltd | Adhesive composition for semiconductor device and adhesive sheet for semiconductor device using the same |
| JP2006199937A (en) * | 2004-12-15 | 2006-08-03 | Tamura Kaken Co Ltd | Conductive adhesive and conductive part and electronic part module using the same |
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| US5136365A (en) * | 1990-09-27 | 1992-08-04 | Motorola, Inc. | Anisotropic conductive adhesive and encapsulant material |
| JP2003165825A (en) * | 2001-11-30 | 2003-06-10 | Mitsui Chemicals Inc | Anisotropic electroconductive paste and method for using the same |
| JP5802081B2 (en) * | 2011-08-24 | 2015-10-28 | 株式会社タムラ製作所 | Anisotropic conductive paste |
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| JP2003049145A (en) | 2001-08-06 | 2003-02-21 | Tomoegawa Paper Co Ltd | Adhesive composition for semiconductor device and adhesive sheet for semiconductor device using the same |
| JP2006199937A (en) * | 2004-12-15 | 2006-08-03 | Tamura Kaken Co Ltd | Conductive adhesive and conductive part and electronic part module using the same |
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| KR20120112047A (en) | 2012-10-11 |
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