JP5144489B2 - Thermosetting resin composition - Google Patents

Description

  The present invention relates to a thermosetting resin composition used as a conductive paste for component mounting, particularly as a thermosetting low-temperature solder paste.

  Conventionally, a material called cream solder has been used to mount an electronic component such as a semiconductor chip on a wiring board or the like. Cream solder is a composition containing solder particles, a flux component and a solvent. In component mounting using this cream solder, the cream solder is heated to a temperature higher than the melting point of the solder particles in a reflow furnace, so that the solder particles melt and an oxide layer on the surface of the solder particles is formed by the flux component at a high temperature. As a result, the solder particles are integrated, thereby ensuring conduction between the conductor wiring such as a wiring board and the electronic component. In such a component mounting process (solder reflow process) using cream solder, many components can be connected together and productivity is high. As the flux component added to the cream solder, rosin component materials represented by abietic acid, various amines and salts thereof, and organic compounds having both terminal carboxylic acids in an aliphatic skeleton such as sebacic acid, azelaic acid, corkic acid, etc. Acids are known.

  By the way, although the melting point of Pb eutectic solder, which is a typical representative solder, is 183 ° C., so-called “Pb-free solder” has begun to be used in accordance with the recent trend of eliminating Pb. The melting point of Pb-free solder is generally higher than that of Pb eutectic solder. For example, in the case of Ag—Sn—Cu-based solder, which is a typical example, it is about 30 ° C. higher than Pb eutectic solder. For this reason, in the solder reflow process using Pb-free solder, component mounting at a high temperature of 215 to 260 ° C. is performed at the maximum temperature.

  For this reason, when mounting an electronic component including a component with low high temperature resistance on a wiring board or the like, it is mounted by spot soldering only on the electronic component in a separate process, or mounted using silver paste or the like It was necessary and productivity was significantly reduced.

  Many Pb-free low melting point solders having a melting point of 180 ° C. or lower by changing the solder alloy composition such as adding Bi are also known. However, there are two problems in using this.

  (1) The low melting point solder is not sufficient in terms of strength and toughness as compared with Pb eutectic solder and Ag-Sn-Cu solder, and if the parts are fixed only by the solder connection part, it may be lost. Cracks are likely to occur in the solder part due to temperature cycles and impacts.

  (2) Conventional flux components dissociate at high temperatures and exert a strong chemical action on metal oxides. Under low-temperature reflow conditions, they do not effectively exhibit flux action, Integration is unlikely to occur.

  In order to solve the problem (1), it is conceivable to use a thermosetting resin as a binder and use a solder paste in which low melting point solder particles are dispersed in the binder. If solder bonding is performed using this solder paste, the component is fixed not only by the solder connection portion but also by a cured product of a thermosetting resin, so that the strength and toughness can be greatly improved. However, an effective flux component that can coexist with the low melting point solder particles in such a solder paste has not been known.

  Further, in order to solve the problem (2), an activator that exhibits good flux characteristics is essential for a special low melting point metal such as Bi. However, rosin component materials represented by abietic acid, various amines and salts thereof, and organic acids having both terminal carboxylic acids in an aliphatic skeleton such as sebacic acid, azelaic acid, corkic acid, etc. In order to reduce the oxide film on the metal surface at a low temperature of ℃ or less, the current state is that the reducibility is insufficient and sufficient characteristics are not obtained. In addition, these activators have not been sufficiently satisfactory in reducing properties for solders containing special metals with low melting points such as Bi and In.

  Therefore, as shown in Patent Document 2, the present inventors have found an activator that exhibits good flux characteristics for a special low melting point metal such as Bi, and uses this as a flux component such as solder paste. Propose that.

  In Patent Document 2, among aliphatic skeleton compounds having carboxyl groups at both ends, succinic acid, glutaric acid, and adipic acid have a low molecular weight and can be dissolved in an epoxy resin at a temperature of 180 ° C. or less. As effective. These are melted when exposed to a temperature of 100 ° C. or higher, and an excellent flux action (reducibility) becomes apparent. Further, even if the compound is not an aliphatic skeleton compound, a compound having a carboxyl group at both ends and having a structure in which an oxygen atom and one or two sulfur atoms are bonded to the main skeleton is an aliphatic skeleton compound. It has been found that it has excellent reducibility compared with the compound. As specific compounds, it has been found that diglycolic acid, thiodiglycolic acid, and dithiodiglycolic acid exhibit excellent flux action. These compounds exhibit a flux action at a low temperature of 130 ° C. or lower, and can efficiently reduce and remove the oxide film on the surface of the low melting point metal.

However, it has been found that these dicarboxylic acids are not sufficiently stored at room temperature because of their excellent flux action at low temperatures. Since these compounds have a melting point higher than room temperature, they are powders (= solid) at room temperature, and reduction reactions are unlikely to occur originally. However, when these compounds are dispersed in the liquid epoxy, the hydrophilic dicarboxylic acid dissolves in the liquid epoxy resin even at room temperature and exerts a flux action, causing a reduction reaction with the solder. It will occur and thicken. For this reason, when the solder paste is left at room temperature, its viscosity gradually increases. When this solder paste is applied at room temperature by dispensing or printing method, the viscosity of the solder paste gradually increases, and the applicability deteriorates. There is a problem that handling is difficult.
Japanese Patent Laid-Open No. 2004-185884 JP 2007-119750 A

  The present invention has been made in view of the above points, and can be mounted by a reflow process at a low temperature by utilizing low-temperature molten solder particles, and has excellent storage stability at room temperature. It aims at providing a thermosetting resin composition.

  As a result of intensive studies, the present inventors have developed a flux component that exhibits low flux activity at room temperature and exhibits an excellent flux action when heated to 180 ° C. or lower, and has completed the present invention.

  The thermosetting resin composition according to the present invention includes a flux component including solder particles having a melting point of 180 ° C. or less, a thermosetting resin binder, and a carboxylic acid anhydride.

  For this reason, this thermosetting resin composition suppresses the flux action of the flux component at room temperature and suppresses the increase in viscosity. When this thermosetting resin composition is used and component mounting is performed under low temperature heating, the solder particles melt and the carboxylic acid anhydride of the flux component is hydrolyzed to generate carboxyl groups, thereby exhibiting the flux action. Then, the oxide layer on the surface of the solder particles is removed, and the integration of the solder particles is promoted, thereby ensuring electrical bondability. Further, the thermosetting resin binder is thermally cured, and the mechanical bondability can be ensured by the cured product.

  In the present invention, the carboxylic acid anhydride preferably contains at least one compound selected from compounds represented by the following structural formulas (1) to (5).

  In this case, the carboxylic acid anhydrides represented by the structural formulas (1) to (3) have a cyclic structure having an internal strain, so that they are likely to cause chemical and thermal ring opening, and polymer type acid anhydrides. The carboxylic acid anhydrides represented by the structural formulas (4) to (5) have an ester-like structure of “— (C═O) —O— (C═O) —” which is easily hydrolyzed inside the molecule. Therefore, ring opening is likely to occur chemically and thermally. For this reason, these carboxylic anhydrides have high reactivity of hydrolysis reaction, and the flux component exhibits an excellent flux action at a low heating temperature.

  In the present invention, the carboxylic acid anhydride is a succinic acid anhydride, glutaric acid anhydride, diglycolic acid anhydride, thiodiglycolic acid anhydride, or a polymer represented by structural formulas (6) to (7). It is also preferable to include at least one compound selected from type anhydrides.

  In this case, succinic anhydride, glutaric anhydride, diglycolic anhydride, and thiodiglycolic anhydride are particularly prone to ring opening because the internal strain of the cyclic structure is particularly large, and the structural formula (6 ) To (7) also have an ester-like structure of “— (C═O) —O— (C═O) —” which is easily hydrolyzed inside the molecule, so that the ring opening is It is particularly likely to occur. For this reason, these carboxylic acid anhydrides have very high reactivity of hydrolysis reaction, and the flux component exhibits particularly excellent flux action at a low heating temperature.

  In the present invention, the thermosetting resin composition preferably contains a reaction accelerator containing at least one compound selected from a heterocyclic compound having a nitrogen atom, a polyamine compound, and an adduct thereof.

  In this case, the hydrolysis reaction of the carboxylic acid anhydride is promoted at a low heating temperature, and the flux component exhibits a further excellent flux action at a low heating temperature.

  In the present invention, the thermosetting resin binder is preferably an epoxy resin.

  In this case, the hydrolysis reaction of the carboxylic acid anhydride is promoted at a low heating temperature, and the flux component exhibits a further excellent flux action at a low heating temperature.

  In this invention, it is also preferable that content of the flux component with respect to a thermosetting resin binder in the thermosetting resin composition is the range of 1-50 phr.

  In this case, the flux component exhibits an excellent flux action at a low heating temperature, and the mechanical bondability of the cured product of the thermosetting resin composition can be further improved.

  In the present invention, the ratio of the total amount of the thermosetting resin binder and the flux component to the total amount of the composition in the thermosetting resin composition is also preferably in the range of 5 to 30% by mass.

  In this case, the mechanical bondability and the electrical bondability of the cured product of the thermosetting resin composition can be further improved.

  In the present invention, the thermosetting resin composition preferably contains a reaction accelerator that promotes hydrolysis of the carboxylic acid anhydride in a range of 5 to 50% by mass with respect to the carboxylic acid anhydride. .

  In this case, the viscosity increase at room temperature of the thermosetting resin composition can be further suppressed, and the hydrolysis reaction of the carboxylic acid anhydride is sufficiently promoted at the heating temperature at a low temperature. An abrupt increase in viscosity of the thermosetting resin composition can be suppressed.

  The thermosetting resin composition according to the present invention exhibits excellent mechanical bondability when used for component mounting and also exhibits excellent electrical bondability even when the heating temperature during mounting is low. Moreover, the increase in viscosity at room temperature is suppressed, the storage stability is high, and the handleability is excellent.

  Hereinafter, the best mode for carrying out the present invention will be described.

  The thermosetting resin composition according to this embodiment contains solder particles, a thermosetting resin binder, and a flux component.

  As the solder particles, solder particles having a melting point of 180 ° C. or less are used. The lower limit of the melting point of the solder particles is preferably 80 ° C. As the solder particles, appropriate ones are used. For example, an alloy based on Sn is used, and specifically, an alloy of Sn and a metal such as Bi, Zn, In or the like is used.

  The content of solder particles in the thermosetting resin composition is preferably in the range of 70 to 95% by mass. If this content is less than 70% by mass, the proportion of solder particles in the thermosetting resin composition is reduced, melting and integration of the solder particles is hindered, and the component of the cured product of the thermosetting resin composition There is a possibility that the electrical bondability may not be sufficiently exhibited. On the other hand, if the content is greater than 95% by mass, the composition becomes highly viscous, which may hinder the coating workability.

  As the thermosetting resin binder, an appropriate thermosetting resin such as an epoxy resin, a polyimide resin, a cyanate ester resin, a benzoxazine resin, or a polyester resin is used. In addition, the thermosetting resin binder needs to have sufficient curability even at the heating temperature in order to exhibit sufficient reinforcement (mechanical bondability) even at a low heating temperature to enable component mounting. From the viewpoint of such low temperature curability and adhesiveness, the thermosetting resin binder is particularly preferably an epoxy resin. In using an epoxy resin as a thermosetting resin binder, it is usually preferable that the thermosetting resin binder contains a liquid epoxy resin, further contains a curing agent, and further contains a curing accelerator or the like as necessary. .

  And in this embodiment, a flux component contains a carboxylic anhydride. Carboxylic anhydride has an acid anhydride structure “— (C═O) —O— (C═O) —” in the molecule and does not have a carboxyl group that exhibits reducibility. The flux action does not occur. For example, the action as a cream solder flux cannot be expected. However, in the thermosetting resin composition containing the thermosetting resin binder as in this embodiment, since a small amount of moisture is contained in the thermosetting resin binder, the low temperature solder at which the low-temperature solder at 180 ° C. or lower melts. Under the heating temperature, the hydrolysis reaction of the carboxylic acid anhydride is promoted to generate a carboxyl group, thereby exhibiting a flux action. On the other hand, the hydrolysis reaction of the carboxylic acid anhydride hardly occurs at room temperature, and the flux action is suppressed. In particular, when a liquid epoxy resin is used as a thermosetting resin binder, the liquid epoxy resin easily contains a minute amount of water, so that hydrolysis of the carboxylic acid anhydride under a low heating temperature is promoted. .

  An appropriate compound is used as the carboxylic acid anhydride, and at least one compound selected from the compounds represented by the structural formulas (1) to (5) is particularly preferable.

  Among these compounds, the compounds represented by the structural formulas (1) to (3) have a structure in which two carboxyl groups are anhydrated and closed. Since these low molecular weight carboxylic acid anhydrides structurally have a small number of atoms forming a ring, they have a large internal strain and are likely to cause ring opening chemically and thermally. For this reason, these carboxylic acid anhydrides have high reactivity of hydrolysis reaction, the hydrolysis reaction proceeds under a low heating temperature, and exhibits an excellent flux action.

  Among these compounds, the compound represented by the structural formula (1) is particularly selected from succinic anhydride (n = 0), glutaric anhydride (n = 1), and adipic anhydride (n = 2). It is preferable that it is at least one kind. Further, as the compound represented by the structural formula (2), diglycolic anhydride (n = 1) is particularly preferable. In addition, as the compound represented by the structural formula (3), thiodiglycolic anhydride (n = 1) is particularly preferable. These acid anhydrides have particularly large internal strain, are particularly susceptible to ring opening chemically and thermally, and are particularly highly reactive in the hydrolysis reaction.

  In addition, the compounds represented by the structural formulas (4) and (5) are polymer type compounds, and have carboxyl groups at both ends, but “— (C═O) —O— ( It has an ester anhydride-like acid anhydride structure of C═O) — ”.

  The carboxylic acid anhydrides represented by the structural formulas (4) and (5) exhibit a flux action by generating a carboxyl group by a hydrolysis reaction. That is, for example, in the compounds represented by the structural formulas (1) to (3), ring opening is caused by a hydrolysis reaction to generate a carboxyl group, which exhibits a flux action. In addition, the compounds represented by the structural formulas (4) and (5) have carboxyl groups at both ends, but since they are polymer type compounds, the equivalent of the carboxyl group is large, and as such, sufficient flux action cannot be exhibited. The function as a flux component does not become apparent. In the compounds represented by the structural formulas (4) and (5), the anhydride structure “— (C═O) —O— (C═O) —” in the molecular chain is cleaved by hydrolysis, resulting in the number of carboxyl groups. It increases and exhibits a sufficient flux effect, and the function as a flux component becomes obvious. In addition, the carboxylic acid anhydrides represented by the structural formulas (4) and (5), which are polymer type acid anhydrides, are easily hydrolyzed inside the molecule "-(C = O) -O- (C = O)-" Therefore, ring opening is likely to occur chemically and thermally. For this reason, these carboxylic anhydrides have high reactivity of hydrolysis reaction, and the flux component exhibits an excellent flux action at a low heating temperature.

  As the compound represented by the structural formula (4), a compound represented by the above structural formula (6) in which m in the formula is 10 is particularly preferable. Moreover, as a compound shown to Structural formula (5), the compound shown to the said Structural formula (7) whose m in a formula is 6 is especially preferable. These carboxylic acid anhydrides are particularly highly reactive in the hydrolysis reaction.

  The carboxylic acid anhydride contained in the flux component may be one kind or two or more kinds. Further, the flux component is preferably composed only of a carboxylic acid anhydride, but may contain a compound generally used as a flux other than the carboxylic acid anhydride.

  Although content of the flux component in a thermosetting resin composition is set suitably, it is preferable that especially the ratio of the flux component with respect to a thermosetting resin binder is the range of 1-50 phr. If this content is less than 1 phr, the concentration of the flux component may be too thin to exhibit a sufficient flux effect, and if this content is greater than 50 phr, the thermosetting resin composition is cured. There is a risk that the mechanical bondability of parts due to objects may not be sufficiently exhibited.

  The total amount of the thermosetting resin binder and the flux component in the thermosetting resin composition is preferably in the range of 5 to 30% by mass with respect to the total amount of the thermosetting resin composition. If this ratio is less than 5% by mass, the fluidity of the thermosetting resin composition before curing becomes insufficient, or the amount of voids generated in the cured product of the thermosetting resin composition increases. As a result, there is a possibility that the mechanical bondability of the part by the cured product of the thermosetting resin composition may not be sufficiently exhibited. On the other hand, if this proportion is larger than 30% by mass, the proportion of solder particles in the thermosetting resin composition is reduced, and the fusion integration of the solder particles is hindered. There is a possibility that the electrical bondability may not be sufficiently exhibited.

  Moreover, it is preferable that the thermoplastic resin composition which concerns on this embodiment contains reaction promoters, such as an acidic substance and a basic substance which accelerate the hydrolysis reaction of carboxylic anhydride.

  Although a suitable compound is used as the reaction accelerator, a heterocyclic compound containing a nitrogen atom, a polyamine compound, and an adduct thereof are highly effective in promoting a hydrolysis reaction of a carboxylic acid anhydride and are particularly effective as a reaction accelerator. is there. The adduct of the polyamine compound means a compound obtained by reacting another compound with a hydrogen atom of a highly reactive tertiary amine. Specific examples of the reaction accelerator include various imidazoles and salts thereof, DBU (diazabicycloundecene) and DBN (diazabicyclononene) and salts thereof, and various amine compounds and adducts thereof. These compounds overlap with compounds that are generally used as curing accelerators that accelerate the curing reaction of the epoxy resin composition. For this reason, when an epoxy resin is used as the thermosetting resin binder, these reaction accelerators also promote the reaction between the carboxylic acid produced and the epoxy resin after hydrolysis of the carboxylic acid anhydride, and thermosetting This also contributes to an improvement in the crosslink density of the cured product of the conductive resin composition.

  The content of the reaction accelerator in the thermosetting resin composition is appropriately adjusted so that the hydrolysis reaction of the carboxylic acid anhydride is sufficiently promoted under the heating temperature at a low temperature and the flux action is exhibited. However, if the content is too high, the hydrolysis reaction of the carboxylic acid anhydride is promoted even at room temperature, causing an increase in viscosity, and sufficient storage stability of the thermosetting resin composition at room temperature can be secured. In particular, when an epoxy resin is used as a thermosetting resin binder, the curing reaction of the epoxy resin is excessively accelerated, and the curing reaction of the epoxy resin proceeds in parallel with the hydrolysis reaction of the carboxylic acid anhydride. This may cause an increase in viscosity. For this reason, it is preferable that content of a reaction accelerator is 5-50 mass% with respect to carboxylic anhydride.

  In addition, the thermosetting resin composition according to the present embodiment may contain commonly used modifiers, additives, and the like other than those described above as long as the object of the present invention is not violated. For example, the thermosetting resin composition may contain a low-boiling solvent or a plasticizer for the purpose of reducing viscosity or imparting fluidity.

  The thermosetting resin composition according to the present embodiment can be produced, for example, by mixing and kneading solder particles, a thermosetting resin binder, a flux component, and various additives as necessary. The thermosetting resin composition is preferably prepared to have an appropriate viscosity that can be applied by a screen printing method or the like.

  Since this thermosetting resin composition contains the flux component containing a carboxylic acid anhydride as described above, the flux action of the flux component is suppressed at room temperature. For this reason, the increase in the viscosity of the thermosetting resin composition at room temperature is suppressed, and the storage stability is high.

  Using the thermosetting resin composition according to the present embodiment, an electronic component can be mounted on a substrate or the like having conductor wiring. For example, when a chip component for surface mounting is used as an electronic component and a printed wiring board is used as a substrate, a thermosetting resin composition is applied to a pad on the printed wiring board by a screen printing method or the like. The chip parts are arranged so that the terminals of the chip parts and the positions of the pads coincide with each other. In this state, the thermosetting resin composition is heated to a low heating temperature by, for example, a solder reflow process in which the printed wiring board on which the chip components are arranged is heated in a reflow furnace. This heating temperature is set to an appropriate temperature at which the solder particles are sufficiently melted and the curing reaction of the thermosetting resin binder proceeds sufficiently. The heating temperature is preferably set so that the curing reaction of the epoxy resin proceeds before the solder particles are completely melted and the aggregation of the solder particles is not hindered. A preferable heating temperature for this purpose is not less than a temperature 10 ° C. higher than the melting point of the solder particles and not more than 60 ° C. higher than the melting point. For example, when the solder particles have a Bi58Sn42 solder composition defined by JIS Z3282, the melting point is 139 ° C., and the heating temperature in this case is preferably in the range of 140 to 200 ° C., and particularly preferably in the range of 150 to 180 ° C. .

  When the thermosetting resin composition is heated in this manner, the solder particles melt and the carboxylic acid anhydride contained in the flux component in the thermosetting resin composition undergoes a hydrolysis reaction to generate a carboxyl group. The flux component exerts the flux action. This flux action removes the oxide layer on the surface of the solder particles, promotes the integration of the solder particles, melts the solder particles together with the pads and the terminals, and between the pads of the chip component and the pads of the printed wiring board. The electrical connection is made. Further, the thermosetting reaction of the thermosetting resin binder in the thermosetting resin composition proceeds, and the chip component and the printed wiring board are mechanically joined. Thereby, a chip component is mounted on the printed wiring board, and a printed circuit board is produced.

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

Example 1
Using a solder alloy having a Bi58Sn42 solder composition defined in JIS Z3282, solder particles were produced from this solder alloy according to a conventional method. The average particle size of the solder particles was 15 μm and the melting point was 139 ° C.

  85 parts by weight of the solder particles, 10 parts by weight of a liquid epoxy resin (“YD128” manufactured by Tohto Kasei), 1 part by weight of a reaction accelerator (modified aliphatic polyamine; “Fujicure FXB-1050” manufactured by Fuji Kasei Kogyo), succinic anhydride 4 parts by weight was blended and uniformly mixed using a disper to prepare a paste-like thermosetting resin composition.

(Example 2)
In Example 1, glutaric anhydride was used as a flux component. The other conditions were the same as in Example 1, and a thermosetting resin composition was prepared.

(Example 3)
In Example 1, diglycolic anhydride was used as a flux component. The other conditions were the same as in Example 1, and a thermosetting resin composition was prepared.

Example 4
In Example 1, thiodiglycolic anhydride was used as a flux component. The other conditions were the same as in Example 1, and a thermosetting resin composition was prepared.

(Example 5)
In Example 1, a polymer type acid anhydride (“SL-12AH” manufactured by Okamura Oil Co., Ltd.) represented by the above structural formula (6) was used as a flux component. The other conditions were the same as in Example 1, and a thermosetting resin composition was prepared.

(Example 6)
In Example 1, a polymer type acid anhydride represented by the above structural formula (7) (“IPU-22AH” manufactured by Okamura Oil Co., Ltd.) was used as a flux component. The other conditions were the same as in Example 1, and a thermosetting resin composition was prepared.

(Example 7)
In Example 1, 0.5 part by weight of diazabicycloundecene (DBU) was used as a reaction accelerator, and 4.5 parts by weight of glutaric anhydride was used as a flux component. The other conditions were the same as in Example 1, and a thermosetting resin composition was prepared.

(Example 8)
In Example 1, 1.5 parts by weight of 2-ethyl-4-methylimidazole (2E4MZ) and 3.5 parts by weight of diglycolic anhydride were used as a reaction accelerator. The other conditions were the same as in Example 1, and a thermosetting resin composition was prepared.

Example 9
In Example 1, 95 parts by weight of solder particles, 3 parts by weight of liquid epoxy resin, 0.5 parts by weight of reaction accelerator, 1.5 parts by weight of succinic anhydride are used. Changed to parts by weight. The other conditions were the same as in Example 1, and a thermosetting resin composition was prepared.

(Example 10)
In Example 1, 70 parts by weight of solder particles, 25 parts by weight of liquid epoxy resin, 1.5 parts by weight of reaction accelerator, and 3.5 parts by weight of succinic anhydride are used. Changed to parts by weight. The other conditions were the same as in Example 1, and a thermosetting resin composition was prepared.

(Example 11)
In Example 1, 0.5 parts by weight of diglycolic acid anhydride as a flux component, and 0.5 parts by weight of a polymeric acid anhydride (“SL-12AH” manufactured by Okamura Oil Co., Ltd.) represented by the structural formula (6) above. Using. The other conditions were the same as in Example 1, and a thermosetting resin composition was prepared.

(Comparative Example 1)
85 parts by weight of the same solder particles as in Example 1, 10 parts by weight of liquid epoxy resin (“YD128” manufactured by Toto Kasei), 3 parts by weight of sebacic acid as a flux component, and 2 parts by weight of Amicure PN23 (manufactured by Ajinomoto Fine Techno) as a curing agent It mix | blended and mixed uniformly using the disper and the paste-form thermosetting resin composition was prepared.

(Comparative Example 2)
A thermosetting resin composition was prepared under the same conditions as in Example 1 except that the flux component was not blended.

(Comparative Example 3)
A thermosetting resin composition was prepared under the same conditions as in Example 1 except that no liquid epoxy resin was blended.

(Comparative Example 4)
Instead of the solder particles in Example 1, 85 parts by weight of silver particles (melting point 950 ° C.) was used. The other conditions were the same as in Example 1, and a thermosetting resin composition was prepared.

(Storage stability evaluation)
The viscosity of the thermosetting resin composition immediately after being prepared by each Example and each Comparative Example was measured with a B-type viscometer. The thermosetting resin composition was allowed to stand at room temperature for 48 hours, and then its viscosity was measured again with a B-type viscometer. The viscosity ratio was calculated by dividing the latter measured value by the former measured value.

(Evaluation of solder integrity)
An FR-4 type printed wiring board having Au-plated pads was prepared, and the thermosetting resin composition was applied to the pads on the printed wiring board by a screen printing method. The coating thickness of the thermosetting resin composition on the pad was about 70 μm.

  A semiconductor chip was disposed as a chip component on the printed wiring board, and the position of the terminal of the semiconductor chip was matched with the position of the pad, and a thermosetting resin composition was interposed between the terminal and the chip.

  The printed wiring board on which this semiconductor chip was placed was heated in an oven at 150 ° C. for 10 minutes, whereby the semiconductor chip was mounted on the printed wiring board to obtain a printed circuit board.

The cured product of the thermosetting resin composition on the printed circuit board was observed with a microscope, and the degree of integration of the solder in the cured product was evaluated as follows.
A: All the solder particles are integrated into a sphere, and a complete two-layer separation structure is confirmed in which a layer of a cured resin that does not contain solder particles surrounds it.
◯: Most of the solder particles are integrated, and a cured resin layer containing some particles around the solder particles is confirmed.
(Triangle | delta): Although a considerable solder particle gathers spherically, the layer of the cured resin which contains many solder particles around it is confirmed.
X: Integration of solder particles is not confirmed.

(Tackiness evaluation)
In order to confirm the degree of curing of the cured product of the thermosetting resin composition, the presence or absence of tackiness on the surface of the cured product of the thermosetting resin composition in the printed circuit board prepared for the solder integration evaluation Was confirmed by a hand test.

(Evaluation of component connection resistance)
As a chip component, a 0Ω 1608 chip resistor (tin electrode) was used instead of the semiconductor chip, and this chip resistor was mounted on a printed wiring board in the same manner as in the case of the solder integration evaluation. Furthermore, after-baking which heats at 150 degreeC with a dryer for 30 minutes was given.

  The resistance value between the pads to which the chip resistors were connected in the printed circuit board thus obtained was measured.

(Chip component share strength)
The shear strength of the chip resistor in the printed circuit board produced for the evaluation of the component connection resistance value was measured by a trimming peel test using a bond tester (series 4000 manufactured by dage).

(Evaluation results)
The results of the above evaluation tests are shown in Table 1 below.

Claims (7)

A flux component containing solder particles having a melting point of 180 ° C. or less, a thermosetting resin binder, and a carboxylic acid anhydride , wherein the carboxylic acid anhydride is represented by the following structural formulas (4) to (5) A thermosetting resin composition comprising at least one selected compound .

The carboxylic acid anhydride is succinic acid anhydride, glutaric acid anhydride, diglycolic acid anhydride, thiodiglycolic acid anhydride, and a polymer type acid anhydride represented by structural formulas (6) to (7). The thermosetting resin composition according to claim 1 , comprising at least one selected compound.

The thermosetting resin composition according to claim 1 or 2 , comprising a reaction accelerator containing at least one compound selected from a heterocyclic compound having a nitrogen atom, a polyamine compound, and an adduct thereof. The thermosetting resin composition according to any one of claims 1 to 3 , wherein the thermosetting resin binder is an epoxy resin. The thermosetting resin composition according to any one of claims 1 to 4 , wherein the content of the flux component with respect to the thermosetting resin binder is in the range of 1 to 50 phr. The thermosetting resin composition according to any one of claims 1 to 5 ratio of the total amount of the thermosetting resin binder and a flux component characterized in that it is in the range of 5 to 30 mass% relative to the total amount of the composition object. Reaction accelerator to accelerate the hydrolysis of a carboxylic acid anhydride, in any one of claims 1 to 6, characterized by containing in the range of 5 to 50 mass% with respect to the carboxylic acid anhydride The thermosetting resin composition as described.