JP5464463B2 - Thermosetting resin composition and circuit board - Google Patents

Description

  The present invention relates to a conductive paste for component mounting, in particular, a thermosetting resin composition used as a thermosetting low-temperature solder paste, and a circuit board on which components are mounted using this thermosetting resin composition.

In recent years, electronic components with low heat resistance such as CCD (Charge Coupled Device) have begun to be mounted along with the enhancement of functions of electronic devices. In addition, since the circuit board to be mounted has become thinner as the density increases, the problem that the circuit board is warped when exposed to a high temperature of 200 ° C. or higher has become apparent. Therefore, in the conductive connection of components to the printed circuit board, mounting connection at a low temperature of 150 ° C. or lower is desired. As the conductive connection material, a material called silver paste or cream solder is generally used (for example, see Patent Document 1). However, since the reflow temperature of cream solder is a high temperature of 215 to 260 ° C., spot solder is used to mount parts that cannot withstand this temperature or to thin printed boards that are likely to warp. Since the mounting is performed in a separate process or a silver paste that is normally cured at a temperature of 150 ° C. or lower is used, productivity is significantly reduced.
Japanese Patent Laid-Open No. 2004-185884

  Silver paste is a mixture of epoxy resin and silver powder in a high filling ratio. Usually, the epoxy resin is cured at a temperature of 160 ° C. or less to adhere to the adherend, and electricity flows through contact with the silver particles. The mechanism is taken. Since silver particles need to be in contact with each other, it is essential that the filling ratio be a fairly high ratio. However, this mechanism inevitably reduces the proportion of the epoxy resin that contributes to adhesion, and thus silver paste generally has a problem of low adhesion. Furthermore, the occurrence of migration due to the ionization of silver is a cause of the occurrence of defects in the mounted components.

  On the other hand, cream solder is a composition containing solder particles, a flux component and a solvent, and after heating in a reflow furnace, the flux components remove the oxide layer on the surface of the solder particles, so that the solder particles have a melting point or higher. It melts and the solder particles are integrated to complete component mounting, and provides a highly productive process in which many components can be connected together. Since this solder bonding is performed by metal fusion bonding with the metal of the adherend, extremely high adhesion strength can be exhibited as compared with the silver paste.

  By the way, as for the type of solder, Sn—Pb eutectic solder has been banned from use due to increasing environmental problems, and Sn—Ag—Cu based solder containing no lead is mainly used. Since the melting point of this Sn—Ag—Cu solder is 215 ° C. or higher, it is in a situation where problems occur in mounting components with low heat resistance or mounting on a thin printed board, and can be mounted and connected at 150 ° C. or lower. Is desired.

  Solder joints have the merit of exhibiting high adhesion strength as described above. However, due to the characteristics of the metal that always has a constant melting point, if it is exposed to a temperature higher than the melting point again after the first connection. There is a problem of remelting. For example, when the solder connection part is covered with resin, when it is again exposed to high temperature, the molten solder is pushed by the volume-expanded resin, flows through the resin gap, and in some cases, the solder is connected with each other This causes a circuit short trouble (so-called flash short). In addition, since the melting point of silver particles is as high as 900 ° C. or higher and the epoxy resin is solidified, the silver paste has no fear of remelting.

  In view of the above, there has been a strong demand for a conductive connection material that can be connected at a low temperature of 150 ° C. or less and that hardly remelts.

  The present invention has been made in view of the above points, and in mounting electronic circuits including components that cannot withstand high temperatures, metal fusion bonding is possible even at a low temperature of 150 ° C. or less, and the molten metal and thermosetting Since the parts are connected with both of the conductive resin, it has high adhesive strength. Furthermore, after the metal melts at a temperature of 150 ° C or less, flash short circuit occurs due to remelting or liquefaction like ordinary solder. It is an object of the present invention to provide a thermosetting resin composition having a characteristic that it is difficult and a circuit board on which components are mounted using the thermosetting resin composition.

The thermosetting resin composition according to claim 1 of the present invention is a thermosetting resin composition containing a thermosetting resin binder, a metal powder, and a flux component. As the metal powder, 5 to 15 mass% of Ag, First alloy particles containing 15 to 25% by mass of Bi, 10 to 20% by mass of Cu, 15 to 25% by mass of In, and 15 to 55% by mass of Sn, 25 to 40% by mass of Ag, and 2 of Bi Second alloy particles containing -8 mass%, Cu 5-15 mass%, In 2-8 mass%, Sn 29-66 mass%, and the mixing ratio of the first and second alloy particles, The second alloy particles are 90 to 110 parts by mass with respect to 100 parts by mass of the first alloy particles, and part or all of the first and second alloy particles are dissolved at a temperature of 150 ° C. or lower to form an intermetallic compound. The one with the characteristic is used, and the flux component To at least one it is used of the compound represented by the following structural formula (1) and (2), Y in the following structural formula (1) or (2), by the following structural formula (9) to (12) at least one der Rukoto atom or group represented is characterized in.

  The invention according to claim 2 is the metal powder according to claim 1, wherein the first alloy particles, the second alloy particles, Ag is 5 to 15% by mass, Bi is 2 to 8% by mass, and Cu is 49 to 81. And 3rd alloy particles containing 2 to 8% by mass of In and 10 to 20% by mass of Sn, and the mixing ratio of the first, second and third alloy particles is 100 parts by mass of the first alloy particles. On the other hand, the second alloy particles are 50 to 60 parts by mass and the third alloy particles are 50 to 60 parts by mass, and a part or all of the first, second and third alloy particles are dissolved at a temperature of 150 ° C. or less. What has the characteristic which forms an intermetallic compound is used, It is characterized by the above-mentioned.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein X in the structural formula (1) or (2) is at least one of organic groups represented by the following structural formulas (3) to (8). It is characterized by being.

The invention according to claim 4 is the method according to any one of claims 1 to 3, wherein the compound represented by the structural formula (1) or (2) is levulinic acid, glutaric acid, succinic acid, malic acid, 5- Groups of ketohexanoic acid, 3-hydroxypropionic acid, 4-aminobutyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid It is at least 1 sort (s) chosen from these, It is characterized by the above-mentioned.

The invention according to claim 5 is any one of claims 1 to 3 , wherein the compound represented by the structural formula (1) or (2) is diglycolic acid, thiodiglycolic acid, or dithiodiglycolic acid. It is at least one selected from the group.

The invention according to claim 6 is characterized in that, in any one of claims 1 to 5 , an epoxy resin is used as the thermosetting resin binder.

The invention according to claim 7 is characterized in that, in any one of claims 1 to 6 , the flux component is contained in an amount of 3 to 50 PHR with respect to the thermosetting resin binder.

The invention according to claim 8 is the invention according to any one of claims 1 to 7 , wherein the total amount of the thermosetting resin binder and the flux component is 5 to 30% by mass with respect to the total amount of the thermosetting resin composition. It is characterized by this.

The invention according to claim 9 is characterized in that in any one of claims 1 to 8 , an antioxidant is contained.

The invention according to claim 10 is characterized in that, in claim 9 , the antioxidant contains a compound containing at least one of a sulfur atom and a phosphorus atom.

The invention according to claim 11 is the invention according to claim 10, wherein the compound containing at least one of a sulfur atom and a phosphorus atom is at least one selected from the group represented by the following structural formulas (13) to (17). It is characterized by.

The invention according to claim 12 is characterized in that, in any one of claims 9 to 11 , the content of the antioxidant is in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the metal powder. It is what.

The invention according to claim 13 is characterized in that in any one of claims 1 to 12 , a storage stabilizer is contained.

The invention according to claim 14 is characterized in that in claim 13 , the storage stabilizer contains an organic phosphate.

The invention according to claim 15 is characterized in that, in claim 14 , the organic phosphate ester is at least one selected from the group consisting of trimethyl phosphate, triethyl phosphate, tributyl phosphate, and triphenyl phosphate. Is.

The invention according to claim 16 is characterized in that, in any one of claims 13 to 15 , the content of the storage stabilizer is in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the metal powder. To do.

The invention according to claim 17 is characterized in that, in any one of claims 1 to 16 , an amine compound having an alcoholic OH group is contained.

The invention according to claim 18 is the invention according to claim 17, wherein the amine compound having an alcoholic OH group is at least one selected from the group consisting of diethanolamine, triethanolamine, N, N-diethylethanolamine, and N-butyldiethanolamine. It is characterized by being.

The invention according to claim 19 is the invention according to claim 17 or 18, wherein the content of the amine compound having an alcoholic OH group is in the range of 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the metal powder. It is characterized by.

A circuit board according to a twentieth aspect of the present invention is characterized in that a component is bonded to a substrate using the thermosetting resin composition according to any one of the first to nineteenth aspects. is there.

According to the thermosetting resin composition of the first aspect of the present invention, when a component that cannot withstand high temperatures is mounted on a substrate, metal fusion bonding is possible even at a low temperature of 150 ° C. or lower, and the molten metal and Since the parts are connected with both thermosetting resin, high adhesive strength can be obtained, and after the metal melts at a temperature of 150 ° C or less, flash caused by remelting or liquefaction like ordinary solder・ Short-circuiting can be prevented. Moreover, compared with other flux components, the oxide film of the metal powder can be sufficiently removed.

  According to the second aspect of the invention, by further including the third alloy particles containing relatively high Ag and Cu having a high melting temperature, it is possible to further prevent re-melting and to prevent flash short circuit. It can be done.

  According to the invention which concerns on Claim 3, the oxide film of a metal powder can be removed effectively.

According to the invention which concerns on Claim 4 , the oxide film of a metal powder can be removed much more effectively.

According to the invention of claim 5 , diglycolic acid, thiodiglycolic acid, and dithiodiglycolic acid all have carboxyl groups at both ends, but do not melt at room temperature, so the flux activity is not so high. Excellent storage stability at room temperature. On the other hand, when these compounds are heated to a temperature of 100 ° C. or higher, they melt, and an excellent activity power (reducing power) is manifested to promote the reaction between the carboxyl group and the metal oxide film on the surface of the metal powder. Thus, the oxide film can be effectively removed. For this reason, integration of the metal powder melted by low-temperature heating can be promoted.

According to the invention of claim 6 , since the epoxy resin is cured at a relatively low temperature and has high adhesiveness, it exhibits sufficient curability even at a temperature lower than that of the conventional solder reflow treatment and enables component mounting. A sufficient reinforcing effect can be exhibited.

According to the invention which concerns on Claim 7 , while being able to fully exhibit the effect | action of a flux component, the reinforcement property after hardening of a thermosetting resin composition can be acquired highly.

According to the invention which concerns on Claim 8 , the thermosetting resin composition which can be flowed can be obtained, and also from the hardened | cured material of the thermosetting resin binder in which a void does not exist around the melt-integrated metal powder. The resin layer is formed, and sufficient reinforcement can be obtained by this resin layer, and it is possible to prevent the fusion and integration of the metal powder from being inhibited, and to obtain a sufficiently low connection resistance. It can be done.

According to the invention which concerns on Claim 9 , the oxidation of the metal powder in a thermosetting resin composition can be prevented.

According to the invention of claim 10 , the compound containing at least one of the sulfur atom and the phosphorus atom oxidizes when heated, thereby preventing oxidation of the metal powder as compared with the case of using another antioxidant. It is something that can be done.

According to the invention which concerns on Claim 11 , the effect of integration of metal powder can be acquired highly.

According to the twelfth aspect of the invention, it is possible to sufficiently prevent the metal powder from being oxidized while preventing the curability of the thermosetting resin composition from being lowered.

According to the invention of claim 13 , the storage stability of the thermosetting resin composition at room temperature can be improved.

According to the invention of claim 14 , the organic phosphate ester and the flux component contained in the storage stabilizer form a salt at room temperature, so that the effect of storage stabilization can be further enhanced. .

According to the invention according to claim 15, when trimethyl phosphate, triethyl phosphate, tributyl phosphate, and triphenyl phosphate are used among organic phosphate esters, storage stability is improved as compared with other organic phosphate esters. It is possible to obtain a high effect.

According to the sixteenth aspect of the invention, the storage stability at room temperature can be sufficiently improved while preventing the curability of the thermosetting resin composition from decreasing.

According to the invention which concerns on Claim 17 , the oxidation of the metal powder in a thermosetting resin composition can be prevented.

According to the invention of claim 18 , when diethanolamine, triethanolamine, N, N-diethylethanolamine, N-butyldiethanolamine is used among the amine compounds having an alcoholic OH group, the effect of integration of the metal powder is achieved. Can be obtained high.

According to the nineteenth aspect of the invention, it is possible to sufficiently prevent the metal powder from being oxidized while preventing the curability of the thermosetting resin composition from being lowered.

According to the circuit board of the twentieth aspect of the present invention, it is possible to obtain high adhesion of the component to the substrate and to remarkably reduce the resistance value between the substrate and the component.

  Embodiments of the present invention will be described below.

  The present inventors have studied earnestly, and have a thermosetting resin binder like silver paste, and a composition containing a metal powder in which the metal component melts and aggregates by heat like solder. Was invented. In the metal powder, the metal is melted by heat of 150 ° C. or less, and is melt-bonded between the metals and is also melt-connected to the electrode metal. The thermosetting resin binder covering the periphery of the metal reacts at a temperature of 150 ° C. or lower to form a composite structure of the cured resin and the molten metal. That is, the thermosetting resin composition according to the present invention contains a thermosetting resin binder (matrix resin), metal powder (solder particles), and a flux component as essential components.

  By the way, various solders having a melting point lower than the melting point 215 ° C. of Sn—Ag—Cu-based solder are known. As typical solder, Sn42 / Bi58 alloy (melting point 139 ° C.) is used. Can be mentioned. However, such a solder is liable to be liquefied and remelted at a temperature equal to or higher than the melting point, so that the problem of flashing and short-circuiting easily occurs due to wetting and spreading.

  Therefore, in the present invention, as the metal powder, [1] one containing first alloy particles and second alloy particles and melting at a low temperature of 130 ° C. or lower, or [2] first alloy particles, second alloy particles and The one containing three alloy particles and melting at a low temperature of 150 ° C. or lower is used. In particular, in the metal powder of [2], in addition to the first alloy particles and the second alloy particles, the metal powder is further remelted by further including third alloy particles containing relatively high melting temperatures of Ag and Cu. This makes it difficult to cause flash shorts.

  Here, 1st alloy particle contains 5-15 mass% of Ag, 15-25 mass% of Bi, 10-20 mass% of Cu, 15-25 mass% of In, and 15-55 mass% of Sn. Is.

  The second alloy particles contain 25 to 40% by mass of Ag, 2 to 8% by mass of Bi, 5 to 15% by mass of Cu, 2 to 8% by mass of In, and 29 to 66% by mass of Sn. is there.

  The third alloy particles contain 5-15% by mass of Ag, 2-8% by mass of Bi, 49-81% by mass of Cu, 2-8% by mass of In, and 10-20% by mass of Sn. is there.

  Here, since the melting temperature of Ag and Cu is high and the melting temperature of Bi, In and Sn is low, the contents of Ag and Cu are too high in the first to third alloy particles, and the contents of Bi, In and Sn are contained. If the amount is too small, the melting temperature of the metal powder of [1] [2] will be high, and conversely, the content of Ag and Cu will be too small and the content of Bi, In and Sn When there is too much, the melting temperature of the metal powder of [1] [2] will become low.

  Moreover, in the metal powder of [1], the mixing ratio of the first and second alloy particles is 90 to 110 parts by mass of the second alloy particles with respect to 100 parts by mass of the first alloy particles, and at a temperature of 150 ° C. or less. Part or all of the first and second alloy particles are dissolved to form an intermetallic compound.

  In the metal powder of [2], the mixing ratio of the first, second and third alloy particles is 50 to 60 parts by mass of the second alloy particles and 50 parts by mass of the third alloy particles with respect to 100 parts by mass of the first alloy particles. It is -60 mass parts, It has the characteristic that a part or all of 1st, 2nd and 3rd alloy particle melt | dissolves at the temperature of 150 degrees C or less, and forms an intermetallic compound. Here, since the melting temperature of the third alloy particles is high and the melting temperature of the first and second alloy particles is low, the content of the third alloy particles is too large and the content of the first and second alloy particles is small. If it is too high, the melting temperature of the metal powder of [2] becomes high, and conversely, the content of the third alloy particles is too low and the content of the first and second alloy particles is too high. In this case, the melting temperature of the metal powder of [2] is lowered.

  When the metal powder of [1] or [2] is heated to 150 ° C., a part or more of the metal particles having a melting point at 150 ° C. or lower melt, and the metal particles and electrode metal having no melting point at 150 ° C. or lower. A thermal diffusion reaction takes place between them and a new alloy phase is formed. The alloy phase newly formed after heating partially contains a low melting point phase of 150 ° C. or lower, but a high melting point phase derived from metal particles having no melting point at 150 ° C. or lower, and an intermetallic compound is used as a support. Therefore, even if the temperature is raised again to a reflow temperature of 150 ° C. or higher and 240 ° C., liquefaction and re-melting will not occur. It will be.

  As a method for producing the metal particles (first to third alloy particles) of [1] and [2] above, as a fine powder production technique, a gas atomization method that is a rapid solidification method, a water atomization method, a centrifugal atomization method, A plasma atomizing method may be used, but a gas atomizing method is preferable. In the gas atomization method, an inert gas such as nitrogen gas, argon gas, or helium gas is usually used. However, in the present invention, it is preferable to use helium gas having a low specific gravity, and the cooling rate during granulation is 500. It is preferably in the range of ˜5000 ° C./second.

  When a suitable production method of the first alloy particles is exemplified, Ag 5-15% by mass, Bi 15-25% by mass, Cu 10-20% by mass, In 15-25% by mass, Sn 15-55% by mass in a graphite crucible, Heating and melting at 1300 to 1500 ° C. with a high frequency induction heating device in a helium atmosphere of 99% by volume or more. The purity of each metal is preferably 99% by mass or more. Next, the temperature of the liquid is lowered to 800 to 900 ° C., the molten metal is introduced into the spray tank in the helium gas atmosphere from the tip of the crucible, and then helium gas (purity 99 volume% or more) is supplied from a gas nozzle provided in the vicinity of the crucible tip. The oxygen concentration is less than 0.1% by volume and the pressure is 2.5 ± 5 MPa. The cooling rate at this time is preferably 2500 to 2700 ° C./second.

  Illustrative of a suitable production method of the second alloy particles, put into a graphite crucible in a ratio of Ag25-40 mass%, Bi2-8 mass%, Cu5-15 mass%, In2-8 mass%, Sn29-66 mass%, Heating and melting at 1300 to 1500 ° C. with a high frequency induction heating device in a helium atmosphere of 99% by volume or more. The purity of each metal is preferably 99% by mass or more. Next, after introducing the molten metal from the tip of the crucible into a spray tank in a helium gas atmosphere, helium gas (purity 99% by volume or more, oxygen concentration less than 0.1% by volume, from a gas nozzle provided in the vicinity of the crucible tip, A pressure of 2.5 ± 5 MPa) is ejected and atomized. The cooling rate at this time is preferably 2400 to 2600 ° C./second.

  Illustrating a suitable production method of the third alloy particles, Ag 5-15 mass%, Bi2-8 mass%, Cu49-81 mass%, In2-8 mass%, Sn 10-20 mass%, put in a graphite crucible, Heating and melting at 1300 to 1500 ° C. with a high frequency induction heating device in a helium atmosphere of 99% by volume or more. The purity of each metal is preferably 99% by mass or more. Next, after introducing the molten metal from the tip of the crucible into a spray tank in a helium gas atmosphere, helium gas (purity 99% by volume or more, oxygen concentration less than 0.1% by volume, from a gas nozzle provided in the vicinity of the crucible tip, A pressure of 2.5 ± 5 MPa) is ejected and atomized. The cooling rate at this time is preferably 2400 to 2600 ° C./second.

  The first to third alloy particles have a predetermined particle size by classification, and the average particle size is preferably 0.5 to 40 μm, more preferably 5 to 30 μm. The average particle diameter can be measured by laser particle size measurement. The particle size distribution can be determined according to the paste application. That is, in printing applications, it is preferable to use particles with a relatively wide distribution with emphasis on printability, and in dispensing applications, use particles with a sharp distribution according to the nozzle diameter.

The metal powder [1] is produced by mixing the first and second alloy particles, and the metal powder [2] is produced by mixing the first, second and third alloy particles.
The mixing method is not particularly limited as long as the alloy particles can be uniformly mixed. However, in order to suppress particle oxidation during mixing, the container-sealed type is more preferable than an open-type mixer using an airflow or a stirring blade. It is preferable that the container itself rotates and swings. Furthermore, it is more preferable that the inside of the container containing the alloy particles can be replaced with an inert gas such as nitrogen gas, argon gas, helium gas.

  As a flux component, flux components corresponding to conventional lead-free Sn-Ag-Cu solder, for example, rosin component materials represented by abietic acid, various amines and salts thereof, sebacic acid, adipic acid, etc. Some high-melting-point organic acids dissociate at high temperatures and exert a strong chemical action on metal oxides, but these have low activity at low temperatures of 150 ° C or less and exhibit effective flux action. Therefore, it is difficult to promote fusion bonding of metal powder.

  Therefore, in the present invention, at least one of the compounds represented by the structural formulas (1) and (2) is used as the flux component.

These compounds have a carboxyl group at the end, and the flux activity at room temperature is not so large, but they generate chelates as shown in the following formulas (18) and (19), and are stable on the surface of each alloy particle. It has the function of effectively removing the oxide film on the surface of the metal powder without being exposed to a high temperature where it is localized and protons completely dissociate. In the following formulas (18) and (19), M represents a metal such as Ag, Bi, Cu, In, or Sn, and R _{1 to} R ₄ are omitted.

  Here, X in the structural formula (1) or (2) is a group capable of forming a chelate with a lone electron pair such as a nitrogen atom, an oxygen atom or a sulfur atom, a carbonyl group, a carboxyl group, or a thiocarbonyl group. , Organic groups having carbon / heteroatom double bonds π electrons such as imino groups, aromatic groups such as phenyl groups, pyridyl groups, imidazolyl groups, and vinyl groups having carbon-carbon double bonds, conjugated doubles Examples thereof include an organic group having a bond.

  Among them, it is preferable that X in the structural formula (1) or (2) is at least one of the organic groups represented by the structural formulas (3) to (8). Thereby, compared with the case where X is another organic group, the oxide film of a metal powder can be removed effectively.

  In particular, it is preferable that Y in the structural formula (1) or (2) is at least one of atoms or atomic groups represented by the structural formulas (9) to (12). Thereby, compared with other flux components, the oxide film of the metal powder can be sufficiently removed.

  Specifically, the compound represented by the structural formula (1) or (2) is levulinic acid, glutaric acid, succinic acid, malic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, 4-aminobutyric acid, 3 -It is preferably at least one selected from the group consisting of mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid and 4-phenylbutyric acid. Thereby, compared with the case where the compound shown by Structural formula (1) or (2) is another compound, the oxide film of a metal powder can be removed more effectively.

  Further, the compound represented by the structural formula (1) or (2) is diglycolic acid (the following structural formula (20)), thiodiglycolic acid (the following structural formula (21)), dithiodiglycolic acid (the following structure). It is also preferable that it is at least one selected from the group of formula (22)).

HOOCH ₂ C—O—CH ₂ COOH (20)
HOOCH ₂ C—S—CH ₂ COOH (21)
HOOCH ₂ C—S—S—CH ₂ COOH (22)
These compounds have a carboxyl group at both ends, but do not melt at room temperature, so the flux activity is not so great, and the storage stability at room temperature is excellent. On the other hand, when these compounds are heated to a temperature of 100 ° C. or higher, they melt, and an excellent activity power (reducing power) is manifested to promote the reaction between the carboxyl group and the metal oxide film on the surface of the metal powder. Thus, the oxide film can be effectively removed. For this reason, integration of the metal powder melted by low-temperature heating can be promoted.

  Examples of the compound having a carboxyl group at both ends generally include glutaric acid having an aliphatic skeleton, adipic acid, pimelic acid, sebacic acid, corkic acid and the like. However, since these metals have insufficient reducing power at a low temperature of 180 ° C. or lower, it is not possible to expect a sufficient reducing action on the oxide film on the metal surface. In particular, special metals having a low melting point such as Bi and In are used. For solder containing, the reducing power is not sufficiently satisfactory.

  In contrast, a compound having a structure in which an oxygen atom or one or two sulfur atoms are bonded to the main skeleton as shown in the above structural formulas (20) to (22) is compared with a compound having an aliphatic skeleton. Can exhibit excellent reducing power. The reason is that the oxygen atom and sulfur atom of the main skeleton are electron-donating atoms, so that the coordination bond with the metal is high, and as a result, the reducing power is superior to that of the aliphatic skeleton compound. It is inferred that this is to be demonstrated.

  In the present invention, at least one of the compounds represented by the structural formulas (1) and (2) may be used, and other commonly used flux components may be used in combination.

  Moreover, it does not restrict | limit especially as a thermosetting resin binder, Appropriate thermosetting resins, such as an epoxy resin, a polyimide resin, a cyanate ester resin, a benzoxazine resin, a polyester resin, can be used. Among these, it is particularly preferable to use an epoxy resin. Epoxy resin cures at a relatively low temperature and has high adhesiveness. Therefore, it exhibits sufficient curability even at temperatures lower than the temperature of conventional solder reflow treatment (about 240 ° C), enabling component mounting and sufficient reinforcement. The effect can be demonstrated.

  When an epoxy resin such as a liquid is used as the thermosetting resin binder, the thermosetting resin composition usually contains a curing agent, or further contains a curing accelerator as necessary.

  As the curing agent, a publicly known and appropriate one can be used. For example, a phenol novolac resin, a naphthalene skeleton-containing phenol resin, a dicyclopentadiene type phenol resin, a phenol aralkyl resin, or the like can be used. Although the usage-amount of a hardening | curing agent is set suitably, it is preferable to make it make the stoichiometric equivalent ratio of the hardening | curing agent with respect to the epoxy equivalent of an epoxy resin become the range of 0.8-1.2. Moreover, when using a hardening accelerator, a publicly known appropriate thing can be used. For example, organophosphorus compounds such as triphenylphosphine and trimethylphosphine, imidazoles such as 2-methylimidazole, 2-phenyl-4-methylimidazole and 2-phenylimidazole, 1,8-diazabicyclo (5,4,0) undecene- 7. Tertiary amines such as triethanolamine and benzyldimethylamine.

  Moreover, it is preferable that 3-50 PHR of flux components are contained with respect to the thermosetting resin binder. Thereby, while being able to fully exhibit the effect | action of a flux component, the reinforcement property after hardening of a thermosetting resin composition can be acquired highly. However, if the content of the flux component is less than 3 PHR, the concentration may be too low to exhibit a sufficient effect as the flux component, so that the fusion integration of the metal powder is hindered and the connection resistance is high. There is a risk of becoming. On the other hand, if the content of the flux component exceeds 50 PHR, tackiness may remain after the thermosetting resin composition is cured, or the reinforcing property may not be sufficiently high. The flux component (PHR) can be calculated by {(mass of flux component / mass of thermosetting resin binder) × 100}. In this case, the thermosetting resin binder includes a curing agent and a curing accelerator.

  Moreover, it is preferable that the total amount of a thermosetting resin binder and a flux component is 5-30 mass% with respect to the thermosetting resin composition whole quantity. In this case, the thermosetting resin binder includes a curing agent and a curing accelerator. Thereby, the flowable thermosetting resin composition can be obtained. In addition, a resin layer made of a cured product of a thermosetting resin binder free from voids is formed around the melted and integrated metal powder, and sufficient reinforcement can be obtained by this resin layer. Furthermore, the fusion integration of the metal powder can be prevented from being hindered, and a sufficiently low connection resistance can be obtained. However, if the total amount of the thermosetting resin binder and the flux component is less than 5% by mass, there is a possibility that it becomes putty or powdery and a flowable thermosetting resin composition cannot be obtained. After the metal powder is melted and integrated, a resin layer made of a cured product of a thermosetting resin binder is formed around the metal powder, and this resin layer contains a lot of voids. Depending on the case, there is a possibility that sufficient reinforcement cannot be obtained. On the other hand, if the total amount exceeds 30% by mass, the proportion of the metal powder is so small that the fusion integration may be hindered or a sufficiently low connection resistance may not be obtained.

  Further, the thermosetting resin composition preferably contains at least one of an antioxidant, a storage stabilizer, and an amine compound having an alcoholic OH group as a function-imparting agent.

  Here, the antioxidant is capable of preventing the oxidation of the metal powder in the thermosetting resin composition and imparts an antioxidant function, and particularly at least one of a sulfur atom and a phosphorus atom. Is preferably included. A compound containing at least one of a sulfur atom and a phosphorus atom is capable of preventing oxidation of the metal powder by oxidizing itself during heating as compared with the case of using another antioxidant. Furthermore, the compound containing at least one of a sulfur atom and a phosphorus atom is preferably at least one selected from the group represented by the structural formulas (13) to (17). Among these, among the compounds containing at least one of a sulfur atom and a phosphorus atom, a high effect of integrating the metal powder can be obtained. And it is preferable that content of such antioxidant is the range of 0.1-10 mass parts with respect to 100 mass parts of said metal powder. While preventing the curability of the thermosetting resin composition from being lowered, the oxidation of the metal powder can be sufficiently prevented. However, if the content of the antioxidant is less than 0.1 parts by mass, the metal powder may not be sufficiently oxidized. Conversely, if the content exceeds 10 parts by mass, the thermosetting resin composition is cured. May decrease.

  In addition, the storage stabilizer can improve the storage stability of the thermosetting resin composition at room temperature and imparts a storage stabilization function, but particularly contains an organic phosphate. Is preferred. Such an organic phosphate ester and the flux component form a salt at room temperature, so that the effect of preservation and stabilization can be further enhanced. Furthermore, this organic phosphate is preferably at least one selected from the group consisting of trimethyl phosphate, triethyl phosphate, tributyl phosphate, and triphenyl phosphate. Among these organic phosphates, the effect of stabilizing the storage can be obtained particularly high. And it is preferable that content of such a storage stabilizer is the range of 1-10 mass parts with respect to 100 mass parts of said metal powder. Thereby, the storage stability at room temperature can be sufficiently improved while preventing the curability of the thermosetting resin composition from decreasing. However, if the content of the storage stabilizer is less than 1 part by mass, the storage stability at room temperature may not be sufficiently improved. Conversely, if it exceeds 10 parts by mass, the thermosetting resin composition is cured. May decrease.

  Moreover, the amine compound which has alcoholic OH group can prevent the oxidation of the metal powder in a thermosetting resin composition. The amine compound having an alcoholic OH group is preferably at least one selected from the group consisting of diethanolamine, triethanolamine, N, N-diethylethanolamine, and N-butyldiethanolamine. Among these, an amine compound having an alcoholic OH group can obtain a high effect of integrating metal powders. And it is preferable that content of such an amine compound which has alcoholic OH group is the range of 0.1-3.0 mass parts with respect to 100 mass parts of said metal powder. Thereby, the oxidation of the metal powder can be sufficiently prevented while preventing the curability of the thermosetting resin composition from being lowered. However, if the content of the amine compound having an alcoholic OH group is less than 0.1 parts by mass, the metal powder may not be sufficiently oxidized. If the content exceeds 3.0 parts by mass, There exists a possibility that the sclerosis | hardenability of curable resin composition may fall.

  The thermosetting resin composition according to the present invention may contain modifiers, additives and the like that are usually used in addition to the essential components. Moreover, a low boiling-point solvent and a plasticizer can also be added in order to reduce the viscosity of a thermosetting resin composition and to provide fluidity. Furthermore, it is also effective to add hardened castor oil or stearamide as a thixotropic agent for maintaining the printed shape.

  The thermosetting resin composition according to the present invention is manufactured by uniformly mixing and kneading a thermosetting resin binder, a metal powder, a flux component, and other components as necessary using a disper or the like. Can do.

  Moreover, when using a liquid epoxy resin as a thermosetting resin binder, a thermosetting resin composition can also be manufactured as follows. That is, after mixing and kneading a metal powder, a flux component composed of at least one of the compounds represented by the structural formulas (1) and (2), and a liquid epoxy resin, a thermosetting resin composition is added by adding a curing agent. You can get things.

  Thus, instead of mixing and kneading the four components of metal powder, flux component, liquid epoxy resin, and curing agent all at once, the three components of metal powder, flux component, and liquid epoxy resin are added before adding the curing agent. By mixing and kneading, the chelate by the metal powder and the flux component can be efficiently formed. In order to make chelate formation more efficiently, it is preferable to leave the three-component kneaded material for a whole day and night to cool to room temperature before adding the curing agent. In addition, if the ratio of the metal powder is high, the temperature of the kneaded product may rise due to frictional heat during kneading, but since no curing agent has been added during this kneading, thickening of the kneaded product is prevented. Is something that can be done. That is, by adding a curing agent that causes a curing reaction with the epoxy resin at the end, it is possible to prevent thickening associated with the reaction of the epoxy resin during the manufacturing process. The reason why the liquid epoxy resin is mixed and kneaded together with the metal powder and the flux component first is to improve the wettability of the surface of the metal powder with this liquid epoxy resin.

  Moreover, when using an epoxy resin as a thermosetting resin binder, a thermosetting resin composition can also be manufactured as follows. That is, a metal powder, a flux component composed of at least one of the compounds represented by the structural formulas (1) and (2), a solvent such as methyl ethyl ketone (MEK), and the like are mixed, and then the solvent is dried and removed. And a thermosetting resin composition can be obtained by adding a hardening | curing agent. Since the solvent can further improve the wettability of the surface of the metal powder than the liquid epoxy resin, and this improves the familiarity of the flux component, as described above, first, the metal powder, the flux component, When the three components of the solvent are mixed and kneaded, a chelate formed of the metal powder and the flux component can be formed more efficiently.

  When these production methods are used, a thermosetting resin composition having the following effects can be obtained. That is, the flux component is adsorbed as a chelate on the surface of the metal powder, and the carboxyl group of the flux component causes a reduction reaction with the metal oxide film at a temperature at which the metal powder melts, thereby helping the integration of the metal powder and the epoxy. Reduces the concentration of flux components that do not act effectively in the thermosetting resin binder made of resin and curing agent, and forms a strong resin layer made of a cured product of thermosetting resin binder around the integrated metal powder It is something that can be done.

Moreover, by using the thermosetting resin composition obtained as described above, the circuit board as shown in FIG. 1 can be obtained by bonding the component 3 to the board 4. That is, for example, when a chip component for surface mounting is used as the component 3 and a printed wiring board such as FR-4 is used as the substrate 4, the pad 5 provided between the printed wiring board and the terminal 6 of the chip component is used. The chip component can be mounted on a printed wiring board by performing reflow soldering with the thermosetting resin composition interposed therebetween. More specifically, the circuit board shown in FIG. 1A has a component 3 mounted by individually applying a thermosetting resin composition to each pad 5. As shown in FIG. 1B, when the circuit board on which the thermosetting resin composition is applied and the component 3 is mounted is heated at, for example, 150 ° C., the metal powder 1 in the thermosetting resin composition is first The metal 5 is melted and integrated with each other, and the pad 5 and the terminal 6 are also melt-bonded. Thereafter, the thermosetting resin binder 2 is cured. In such a process, the composite 10 of the thermosetting resin binder 2 and the molten metal in which the molten metal in a state of being uniformly distributed inside the cured thermosetting resin composition is formed is completed.

  On the other hand, FIG. 2 shows a conventional circuit board. That is, the circuit board shown in FIG. 2A is obtained by bonding the component 3 to the board 4 using the metal powder 1 such as Sn42 / Bi58 alloy (melting point 139 ° C.) without using the thermosetting resin binder. is there. In addition, the circuit board shown in FIG. 2B has a metal powder 1 such as Sn42 / Bi58 alloy (melting point: 139 ° C.) and heat without using any of the flux components represented by the structural formulas (1) and (2). The component 3 is bonded to the substrate 4 using the curable resin binder 2.

  In the circuit board shown in FIG. 2A, since the thermosetting resin binder 2 is not used, the component 3 is fixed to the substrate 4 only by the solder connection portion made of the metal powder 1, and the component 3 becomes the substrate 4. Or cracks are likely to occur in the solder connection portion 7 due to a temperature cycle or impact. Further, when the metal powder 1 in the solder connection portion 7 is remelted, the position of the component 3 may be shifted with respect to the substrate 4. On the other hand, in the circuit board shown in FIG. 1, since the strong resin layer 8 made of the thermosetting resin binder 2 is formed around the solder connection portion 7 made of the metal powder 1, the component 3 is removed from the board 4. In addition, the solder connection portion 7 is not cracked by a temperature cycle or impact. Even if the metal powder 1 of the solder connection portion 7 is remelted, the resin layer 8 around the metal powder 1 is not remelted, so that the position of the component 3 is not shifted from the substrate 4.

  In the circuit board shown in FIG. 2B, although the thermosetting resin binder 2 is used, an effective flux component is not used. Therefore, an oxide film on the surface of each metal powder constituting the metal powder 1 is used. Cannot be sufficiently removed, the fusion and integration of the metal powder 1 is hindered, and the resistance value between the component 3 and the substrate 4 is increased. On the other hand, in the circuit board shown in FIG. 1, since at least one of the flux components represented by the structural formulas (1) and (2) is used, the surface of each metal powder constituting the metal powder 1 is used. The oxide film can be sufficiently removed, the fusion integration of the metal powder 1 is promoted, and the resistance value between the component 3 and the substrate 4 can be remarkably reduced.

  In the thermosetting resin composition according to the present invention, since the metal powder of [1] or [2] is used, when mounting a component that cannot withstand high temperatures on a substrate, 150 ° C. Metal melt bonding is possible even at the following low temperatures, and the parts are connected by both the molten metal and the thermosetting resin, so that high adhesive strength can be obtained. Further, after the metal is melted at a temperature of 150 ° C. or less, it is possible to make it difficult to cause flash short-circuit due to remelting or liquefaction like ordinary solder.

  Hereinafter, the present invention will be specifically described by way of examples.

Example 1
As a metal powder, “Y-32” manufactured by Asahi Kasei Electronics Co., Ltd. was used. This metal powder comprises 10% by mass of Ag, 20% by mass of Bi, 15% by mass of Cu, 20% by mass of In, 35% by mass of Sn, 32% by mass of Ag, and Bi. Second alloy particles containing 5% by mass, 10% by mass of Cu, 5% by mass of In and 48% by mass of Sn, 10% by mass of Ag, 5% by mass of Bi, 65% by mass of Cu, and 5% of In And third alloy particles containing 15% by mass of Sn, and the mixing ratio of the first, second, and third alloy particles is 52 parts by mass of the second alloy particles with respect to 100 parts by mass of the first alloy particles. The third alloy particle is 53 parts by mass and has the characteristic of forming an intermetallic compound at a temperature of 150 ° C. or lower. The metal powder has an average particle size of 7 μm and a minimum melting temperature of 65 ° C. In addition, endothermic peaks accompanying melting are observed at 80 ° C., 196 ° C., and 361 ° C.

  Moreover, levulinic acid was used as a flux component.

  In addition, “YD128” manufactured by Toto Kasei Co., Ltd., which is a liquid epoxy resin, and “Amicure PN-23” manufactured by Ajinomoto Fine Techno Co., Ltd., which is a curing agent, were used as the thermosetting resin binder.

  The metal powder (85 parts by mass), the flux component (3 parts by mass), the liquid epoxy resin (10 parts by mass), and the curing agent (2 parts by mass) are uniformly mixed and kneaded using a disper to obtain a paste. A thermosetting resin composition was produced.

  Next, two independent electrode pads were formed on the FR-4 substrate by Au plating by a normal method. This electrode pad was formed to have the same size as the electrode portion of the 1608 type chip resistor. Next, the thermosetting resin composition was supplied to the electrode pad of the FR-4 substrate by screen printing using a metal mask. The thickness of the thermosetting resin composition supplied to the electrode pad was about 70 μm. Then, a 0Ω 1608 type chip resistor (tin electrode) is used as a component, and this chip resistor is mounted on the electrode pad of the FR-4 substrate to form a circuit board. Then, the circuit board is put in an oven at 150 ° C. Heat treatment was performed for 60 minutes.

  Thereafter, the circuit board was taken out from the oven, and the resistance value of the chip resistor (chip component resistance value) was measured by a four-terminal method.

  Moreover, the shear shear strength between the FR-4 substrate and the chip resistance (chip component shear strength) was measured using a bond tester.

  Further, with a B-type rotational viscometer (manufactured by BLOOKFIELD), the viscosity immediately after production of the thermosetting resin composition (η0) and the viscosity after standing at room temperature of 20 ° C. for 20 hours (η20) are measured, and the viscosity is increased. Ratio = (η20 / η0) was calculated.

  In addition, a circuit board formed by mounting a 10Ω 1608 type chip resistor in the same manner as described above is placed in a transfer mold, and an epoxy resin transfer mold sealing material for semiconductor sealing (Matsushita Electric Works ( Overmolding was performed by “CV8710” manufactured by Co., Ltd. to form overmolded circuit components. Further, after-baking was performed, the transfer mold encapsulant for this overmolded circuit component was completely cured. Immediately after this (initial stage), the resistance value of the chip resistance of 10Ω is measured, and the presence or absence of the metal in the thermosetting resin composition portion (flashing in the mold package) is observed with a soft X-ray transmission device. And confirmed. Thereafter, the overmolded circuit component was passed through a reflow furnace having a peak temperature of 260 ° C. 20 times. Immediately after this (after 20 reflows), the resistance value of the chip resistance of 10Ω was measured in the same manner as described above, and the presence or absence of the metal in the thermosetting resin composition portion was observed with a soft X-ray transmission device. Confirmed. In addition, regarding the presence or absence of short circuit in the mold package, after reflowing 20 times, the metal melts out (flash) and the chip resistance is connected between the two electrodes, and the resistance value of the 10Ω chip resistance is reduced to 5Ω or less. Yes, otherwise determined as no short circuit.

(Examples 2 to 14)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 1 except that those shown in the following [Table 1] and [Table 2] were used as the flux components, and their performance was evaluated.

(Example 15)
As a thermosetting resin binder, instead of a liquid epoxy resin and a curing agent, Lonza "L-10" (10 parts by mass) and Fe acetylacetonate (0.1 parts by mass) which are cyanate ester resins are used. Except for the above, a thermosetting resin composition and a circuit board were produced in the same manner as in Example 1, and the performance was evaluated.

(Examples 16 and 17)
As shown in [Table 2] below, as the flux component, a thermosetting resin composition and a circuit board were produced in the same manner as in Example 1 except that two types were used, and the performance was evaluated. did.

(Example 18)
Except for the addition of 3 parts by weight of an antioxidant ("SEENOX 412S" manufactured by Sipro Kasei Co., Ltd., which is a compound represented by the above structural formula (13)) (S-1) as a functionality-imparting agent. The thermosetting resin composition and the circuit board were produced in the same manner as in Example 15, and the performance was evaluated.

(Example 19)
Except for the addition of 3 parts by weight of an antioxidant ("SEENOX DS" manufactured by Sipro Kasei Co., Ltd., which is a compound represented by the above structural formula (14)) (S-2) as a functionality-imparting agent. The thermosetting resin composition and the circuit board were produced in the same manner as in Example 2, and the performance was evaluated.

(Example 20)
Except for the addition of 3 parts by mass of an antioxidant ("SEENOX DL" manufactured by Sipro Kasei Co., Ltd., which is a compound represented by the above structural formula (15)) (S-3) as a function-imparting agent. The thermosetting resin composition and the circuit board were produced in the same manner as in Example 3, and the performance was evaluated.

(Example 21)
Implementation was performed except that 3 parts by mass of an antioxidant ("HCA" manufactured by Sanko Co., Ltd., which is a compound represented by the above structural formula (16)) (S-4) was further added as a function-imparting agent. A thermosetting resin composition and a circuit board were produced in the same manner as in Example 11, and the performance was evaluated.

(Example 22)
Except for the addition of 3 parts by mass of an antioxidant ("ADEKA STAB 2112" manufactured by ADEKA Corporation, which is a compound represented by the above structural formula (17)) (S-5) as a functionality-imparting agent, A thermosetting resin composition and a circuit board were produced in the same manner as in Example 12, and the performance was evaluated.

(Example 23)
A thermosetting resin composition and a circuit board were prepared in the same manner as in Example 1 except that 3 parts by mass of a storage stabilizer (trimethyl phosphate) (H-1) was further added as a functionality-imparting agent. Manufactured and evaluated for its performance.

(Example 24)
A thermosetting resin composition and a circuit board were prepared in the same manner as in Example 2 except that 3 parts by mass of a storage stabilizer (triethyl phosphate) (H-2) was further added as a functionality-imparting agent. Manufactured and evaluated for its performance.

(Example 25)
A thermosetting resin composition and a circuit board were prepared in the same manner as in Example 3 except that 3 parts by mass of a storage stabilizer (tributyl phosphate) (H-3) was further blended as a functionality-imparting agent. Manufactured and evaluated for its performance.

(Example 26)
The thermosetting resin composition and the circuit board were the same as in Example 4 except that 3 parts by mass of a storage stabilizer (triphenyl phosphate) (H-4) was further added as a functionality-imparting agent. Were manufactured and their performance was evaluated.

(Example 27)
The thermosetting resin composition and the circuit were the same as in Example 1 except that 1 part by mass of an amine compound (diethanolamine) (P-1) having an alcoholic OH group was further blended as a function-imparting agent. Substrates were manufactured and their performance was evaluated.

(Example 28)
A thermosetting resin composition as in Example 2 except that 1 part by mass of an amine compound (triethanolamine) (P-2) having an alcoholic OH group was further blended as a function-imparting agent. And the circuit board was manufactured and the performance was evaluated.

(Example 29)
Thermosetting in the same manner as in Example 3 except that 1 part by mass of an amine compound having an alcoholic OH group (N, N-diethylethanolamine) (P-3) was further blended as a function-imparting agent. Resin compositions and circuit boards were produced and their performance was evaluated.

(Example 30)
The thermosetting resin composition was the same as in Example 4 except that 1 part by mass of an amine compound having an alcoholic OH group (N-butyldiethanolamine) (P-4) was further blended as a function-imparting agent. Products and circuit boards were manufactured and their performance was evaluated.

(Comparative Example 1)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 1 except that abietic acid (3 parts by mass) was used as a flux component, and its performance was evaluated.

(Comparative Example 2)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 1 except that sebacic acid (3 parts by mass) was used as a flux component, and its performance was evaluated.

(Example 31)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 1 except that 0.2 parts by mass of levulinic acid was used as a flux component, and the performance was evaluated.

(Example 32)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 1 except that 7 parts by mass of levulinic acid was used as a flux component, and the performance was evaluated.

(Example 33)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 1 except that 30 parts by mass of “Y-32” was used as the metal powder, and the performance was evaluated.

(Example 34)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 1 except that 300 parts by mass of “Y-32” was used as the metal powder, and the performance was evaluated.

(Comparative Example 3)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 1 except that silver particles (85 parts by weight) were used as the metal powder, and the performance was evaluated.

(Comparative Example 4)
A thermosetting resin was used in the same manner as in Example 1 except that a solder powder of Sn-3Ag-0.5Cu (Sn 96.5% by mass, Ag 3% by mass, Cu 0.5% by mass) was used as the metal powder. A composition was prepared.

  Next, two independent electrode pads were formed on the FR-4 substrate by Au plating by a normal method. This electrode pad was formed to have the same size as the electrode portion of the 1608 type chip resistor. Next, the thermosetting resin composition was supplied to the electrode pad of the FR-4 substrate by screen printing using a metal mask. The thickness of the thermosetting resin composition supplied to the electrode pad was about 70 μm. Then, a 0Ω 1608 type chip resistor (tin electrode) is used as a component, and this chip resistor is mounted on the electrode pad of the FR-4 substrate to form a circuit board, and then the circuit board is reflowed at a peak temperature of 260 ° C. And after-baking at 150 ° C. for 1 hour.

  Thereafter, the resistance value of the chip resistor (chip component resistance value) was measured by a four-terminal method.

  Moreover, the shear shear strength between the FR-4 substrate and the chip resistance (chip component shear strength) was measured using a bond tester.

  Further, with a B-type rotational viscometer (manufactured by BLOOKFIELD), the viscosity immediately after production of the thermosetting resin composition (η0) and the viscosity after standing at room temperature of 20 ° C. for 20 hours (η20) are measured, and the viscosity is increased. Ratio = (η20 / η0) was calculated.

  In addition, a circuit board formed by mounting a 10Ω 1608 type chip resistor in the same manner as described above is placed in a transfer mold, and an epoxy resin transfer mold sealing material for semiconductor sealing (Matsushita Electric Works ( Overmolding was performed by “CV8710” manufactured by Co., Ltd. to form overmolded circuit components. Further, after-baking was performed, the transfer mold encapsulant for this overmolded circuit component was completely cured. Immediately after this (initial stage), the resistance value of the chip resistance of 10Ω is measured, and the presence or absence of the metal in the thermosetting resin composition portion (flashing in the mold package) is observed with a soft X-ray transmission device. And confirmed. Thereafter, the overmolded circuit component was passed through a reflow furnace having a peak temperature of 260 ° C. 20 times. Immediately after this (after 20 reflows), the resistance value of the chip resistance of 10Ω was measured in the same manner as described above, and the presence or absence of the metal in the thermosetting resin composition portion was observed with a soft X-ray transmission device. Confirmed. In addition, regarding the presence or absence of short circuit in the mold package, after reflowing 20 times, the metal melts out (flash) and the chip resistance is connected between the two electrodes, and the resistance value of the 10Ω chip resistance is reduced to 5Ω or less. Yes, otherwise determined as no short circuit.

(Comparative Example 5)
A thermosetting resin composition was produced in the same manner as in Example 1, except that Sn-58Bi (Sn 42 mass%, Bi 58 mass%) solder powder was used as the metal powder.

  Next, two independent electrode pads were formed on the FR-4 substrate by Au plating by a normal method. This electrode pad was formed to have the same size as the electrode portion of the 1608 type chip resistor. Next, the thermosetting resin composition was supplied to the electrode pad of the FR-4 substrate by screen printing using a metal mask. The thickness of the thermosetting resin composition supplied to the electrode pad was about 70 μm. Then, a 0Ω 1608 type chip resistor (tin electrode) is used as a component, and this chip resistor is mounted on the electrode pad of the FR-4 substrate to form a circuit board. Then, the circuit board is reflowed at a peak temperature of 160 ° C. And after-baking at 150 ° C. for 1 hour.

  Thereafter, the resistance value of the chip resistor (chip component resistance value) was measured by a four-terminal method.

  Moreover, the shear shear strength between the FR-4 substrate and the chip resistance (chip component shear strength) was measured using a bond tester.

  Further, with a B-type rotational viscometer (manufactured by BLOOKFIELD), the viscosity immediately after production of the thermosetting resin composition (η0) and the viscosity after standing at room temperature of 20 ° C. for 20 hours (η20) are measured, and the viscosity is increased. Ratio = (η20 / η0) was calculated.

  In addition, a circuit board formed by mounting a 10Ω 1608 type chip resistor in the same manner as described above is placed in a transfer mold, and an epoxy resin transfer mold sealing material for semiconductor sealing (Matsushita Electric Works ( Overmolding was performed by “CV8710” manufactured by Co., Ltd. to form overmolded circuit components. Further, after-baking was performed, the transfer mold encapsulant for this overmolded circuit component was completely cured. Immediately after this (initial stage), the resistance value of the chip resistance of 10Ω is measured, and the presence or absence of the metal in the thermosetting resin composition portion (flashing in the mold package) is observed with a soft X-ray transmission device. And confirmed. Thereafter, the overmolded circuit component was passed through a reflow furnace having a peak temperature of 260 ° C. 20 times. Immediately after this (after 20 reflows), the resistance value of the chip resistance of 10Ω was measured in the same manner as described above, and the presence or absence of the metal in the thermosetting resin composition portion was observed with a soft X-ray transmission device. Confirmed. In addition, regarding the presence or absence of short circuit in the mold package, after reflowing 20 times, the metal melts out (flash) and the chip resistance is connected between the two electrodes, and the resistance value of the 10Ω chip resistance is reduced to 5Ω or less. Yes, otherwise determined as no short circuit.

(Example 35)
As a metal powder, “Y-33” manufactured by Asahi Kasei Electronics Co., Ltd. was used. This metal powder comprises 10% by mass of Ag, 20% by mass of Bi, 15% by mass of Cu, 20% by mass of In, 35% by mass of Sn, 32% by mass of Ag, and Bi. Second alloy particles containing 5% by mass, 10% by mass of Cu, 5% by mass of In and 48% by mass of Sn, and the mixing ratio of the first and second alloy particles is 100 parts by mass of the first alloy particles. On the other hand, it is 103 mass parts of 2nd alloy particles, and has the characteristic of forming an intermetallic compound at the temperature of 150 degrees C or less. The metal powder has an average particle size of 8 μm and a minimum melting temperature of 65 ° C. In addition, an endothermic peak accompanying melting is observed at 195 ° C.

  Then, a thermosetting resin composition and a circuit board were produced in the same manner as in Example 1 except that the above metal powder was used, and the performance was evaluated.

(Examples 36 to 48)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 31 except that those shown in the following [Table 5] and [Table 6] were used as flux components, and their performance was evaluated.

(Example 49)
As a thermosetting resin binder, instead of a liquid epoxy resin and a curing agent, Lonza "L-10" (10 parts by mass) and Fe acetylacetonate (0.1 parts by mass) which are cyanate ester resins are used. Except for the above, a thermosetting resin composition and a circuit board were produced in the same manner as in Example 31, and the performance was evaluated.

(Examples 50 and 51)
As shown in [Table 6] below, as the flux component, a thermosetting resin composition and a circuit board were produced in the same manner as in Example 31 except that two types were used, and the performance was evaluated. did.

(Example 52)
Except for the addition of 3 parts by weight of an antioxidant ("SEENOX 412S" manufactured by Sipro Kasei Co., Ltd., which is a compound represented by the above structural formula (13)) (S-1) as a functionality-imparting agent. The thermosetting resin composition and the circuit board were produced in the same manner as in Example 45, and the performance was evaluated.

(Example 53)
Except for the addition of 3 parts by weight of an antioxidant ("SEENOX DS" manufactured by Sipro Kasei Co., Ltd., which is a compound represented by the above structural formula (14)) (S-2) as a functionality-imparting agent. The thermosetting resin composition and the circuit board were produced in the same manner as in Example 32, and the performance was evaluated.

(Example 54)
Except for the addition of 3 parts by mass of an antioxidant ("SEENOX DL" manufactured by Sipro Kasei Co., Ltd., which is a compound represented by the above structural formula (15)) (S-3) as a function-imparting agent. In the same manner as in Example 33, a thermosetting resin composition and a circuit board were produced, and their performance was evaluated.

(Example 55)
Implementation was performed except that 3 parts by mass of an antioxidant ("HCA" manufactured by Sanko Co., Ltd., which is a compound represented by the above structural formula (16)) (S-4) was further added as a function-imparting agent. A thermosetting resin composition and a circuit board were produced in the same manner as in Example 41, and the performance was evaluated.

(Example 56)
Except for the addition of 3 parts by mass of an antioxidant ("ADEKA STAB 2112" manufactured by ADEKA Corporation, which is a compound represented by the above structural formula (17)) (S-5) as a functionality-imparting agent, A thermosetting resin composition and a circuit board were produced in the same manner as in Example 42, and the performance was evaluated.

(Example 57)
A thermosetting resin composition and a circuit board were prepared in the same manner as in Example 1 except that 3 parts by mass of a storage stabilizer (trimethyl phosphate) (H-1) was further added as a functionality-imparting agent. Manufactured and evaluated for its performance.

(Example 58)
A thermosetting resin composition and a circuit board were prepared in the same manner as in Example 32 except that 3 parts by mass of a storage stabilizer (triethyl phosphate) (H-2) was further added as a functionality-imparting agent. Manufactured and evaluated for its performance.

(Example 59)
A thermosetting resin composition and a circuit board were prepared in the same manner as in Example 33 except that 3 parts by mass of a storage stabilizer (tributyl phosphate) (H-3) was further added as a functionality-imparting agent. Manufactured and evaluated for its performance.

(Example 60)
The thermosetting resin composition and the circuit board were the same as in Example 34 except that 3 parts by mass of a storage stabilizer (triphenyl phosphate) (H-4) was further blended as a functionality-imparting agent. Were manufactured and their performance was evaluated.

(Example 61)
The thermosetting resin composition and the circuit were the same as in Example 31 except that 1 part by mass of an amine compound (diethanolamine) (P-1) having an alcoholic OH group was further added as a function-imparting agent. Substrates were manufactured and their performance was evaluated.

(Example 62)
The thermosetting resin composition was the same as in Example 32 except that 1 part by mass of an amine compound (triethanolamine) (P-2) having an alcoholic OH group was further added as a function-imparting agent. And the circuit board was manufactured and the performance was evaluated.

(Example 63)
Thermosetting in the same manner as in Example 33, except that 1 part by mass of an amine compound (N, N-diethylethanolamine) (P-3) having an alcoholic OH group was further added as a function-imparting agent. Resin compositions and circuit boards were produced and their performance was evaluated.

(Example 64)
The thermosetting resin composition was the same as in Example 34 except that 1 part by mass of an amine compound having an alcoholic OH group (N-butyldiethanolamine) (P-4) was further blended as a function-imparting agent. Products and circuit boards were manufactured and their performance was evaluated.

(Comparative Example 6)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 31 except that abietic acid (3 parts by mass) was used as a flux component, and the performance was evaluated.

(Comparative Example 7)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 31 except that sebacic acid (3 parts by mass) was used as the flux component, and the performance was evaluated.

(Example 65)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 31 except that 0.2 parts by mass of levulinic acid was used as a flux component, and the performance was evaluated.

Example 66
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 31 except that 7 parts by mass of levulinic acid was used as a flux component, and the performance was evaluated.

(Example 67)
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 31 except that 30 parts by mass of “Y-33” was used as the metal powder, and the performance was evaluated.

Example 68
A thermosetting resin composition and a circuit board were produced in the same manner as in Example 31 except that 300 parts by mass of “Y-33” was used as the metal powder, and the performance was evaluated.

  The above results are shown in the following [Table 1] to [Table 8].

An example of the circuit board based on this invention is shown, (a) (b) is sectional drawing. An example of the conventional circuit board is shown, (a) (b) is sectional drawing.

Explanation of symbols

1 Metal powder 2 Thermosetting resin binder 3 Parts 4 Substrate

Claims (20)

In the thermosetting resin composition containing a thermosetting resin binder, a metal powder, and a flux component, as a metal powder, Ag is 5 to 15% by mass, Bi is 15 to 25% by mass, Cu is 10 to 20% by mass, First alloy particles containing 15 to 25% by mass of In and 15 to 55% by mass of Sn, 25 to 40% by mass of Ag, 2 to 8% by mass of Bi, 5 to 15% by mass of Cu, and 2 of In Second alloy particles containing ˜8% by mass and second alloy particles containing 29˜66% by mass of Sn, and the mixing ratio of the first and second alloy particles is 100% by mass of the first alloy particles. It is 110 parts by mass, and the one having the property that part or all of the first and second alloy particles are dissolved at a temperature of 150 ° C. or less to form an intermetallic compound is used. Formulas represented by structural formulas (1) and (2) At least one of the object is used, characterized Y in the following structural formula (1) or (2), at least one Der Rukoto atom or group represented by the following structural formula (9) to (12) A thermosetting resin composition.

  As the metal powder, the first alloy particles, the second alloy particles, Ag is 5 to 15 mass%, Bi is 2 to 8 mass%, Cu is 49 to 81 mass%, In is 2 to 8 mass%, Sn is A third alloy particle containing 10 to 20% by mass, and the mixing ratio of the first, second and third alloy particles is 50 to 60 parts by mass of the second alloy particles with respect to 100 parts by mass of the first alloy particles. It is 50-60 parts by mass of the third alloy particles, and those having the characteristic that some or all of the first, second and third alloy particles dissolve at a temperature of 150 ° C. or less to form an intermetallic compound. The thermosetting resin composition according to claim 1, wherein: The heat according to claim 1 or 2, wherein X in the structural formula (1) or (2) is at least one of organic groups represented by the following structural formulas (3) to (8). Curable resin composition.

The compound represented by the structural formula (1) or (2) is levulinic acid, glutaric acid, succinic acid, malic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, 4-aminobutyric acid, 3-mercaptopropionic acid, 3-mercapto isobutyl acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenyl isobutyl acid, any of claims 1 to 3, wherein the at least one selected from the group consisting of 4-phenylbutyric acid 2. The thermosetting resin composition according to item 1. Compound represented by the structural formula (1) or (2), diglycolic acid, thio-diglycolic acid, according to claim 1, wherein the at least one selected from the group consisting of dithiodiglycolic acid The thermosetting resin composition according to any one of the above. The thermosetting resin composition according to any one of claims 1 to 5 , wherein an epoxy resin is used as the thermosetting resin binder. The thermosetting resin composition according to any one of claims 1 to 6 , wherein a flux component is contained in an amount of 3 to 50 PHR with respect to the thermosetting resin binder. The thermosetting according to any one of claims 1 to 7 , wherein the total amount of the thermosetting resin binder and the flux component is 5 to 30% by mass with respect to the total amount of the thermosetting resin composition. Resin composition. The thermosetting resin composition according to any one of claims 1 to 8, characterized in that it contains an antioxidant. The thermosetting resin composition according to claim 9 , wherein the antioxidant contains a compound containing at least one of a sulfur atom and a phosphorus atom. The thermosetting according to claim 10 , wherein the compound containing at least one of a sulfur atom and a phosphorus atom is at least one selected from the group consisting of those represented by the following structural formulas (13) to (17). Resin composition.

The thermosetting resin composition according to any one of claims 9 to 11 , wherein the content of the antioxidant is in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the metal powder. object. The thermosetting resin composition according to any one of claims 1 to 12, characterized in that it contains a storage stabilizer. The thermosetting resin composition according to claim 13 , wherein the storage stabilizer contains an organic phosphate. The thermosetting resin composition according to claim 14 , wherein the organic phosphate is at least one selected from the group consisting of trimethyl phosphate, triethyl phosphate, tributyl phosphate, and triphenyl phosphate. The thermosetting resin composition according to any one of claims 13 to 15 , wherein the content of the storage stabilizer is in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the metal powder. . The thermosetting resin composition according to any one of claims 1 to 16, characterized in that it contains an amine compound having an alcoholic OH group. 18. The heat according to claim 17 , wherein the amine compound having an alcoholic OH group is at least one selected from the group consisting of diethanolamine, triethanolamine, N, N-diethylethanolamine, and N-butyldiethanolamine. Curable resin composition. The thermosetting according to claim 17 or 18 , wherein the content of the amine compound having an alcoholic OH group is in the range of 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the metal powder. Resin composition. A circuit board, wherein a component is bonded to a board using the thermosetting resin composition according to any one of claims 1 to 19 .

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