JPWO2017086335A1 - Solder joint material, connection structure, and manufacturing method of connection structure - Google Patents

Abstract

Provided is a solder joint material that can efficiently arrange solder between electrodes to be connected even if the electrode width or the inter-electrode width is narrow, and can improve conduction reliability and insulation reliability. The solder joint material according to the present invention includes solder particles, a flux, and a binder, and the content of the solder particles exceeds 80% by weight, and the solder particles have an amino group or a thiol group on the outer surface. It contains particles or a compound having an amino group or a thiol group as at least one of the flux and the binder.

Description

  The present invention relates to a solder joint material containing solder particles in an amount exceeding 80% by weight. The present invention also relates to a connection structure using the solder joint material and a method for manufacturing the connection structure.

  Anisotropic conductive materials containing solder are known. The content of solder particles in the anisotropic conductive material is, for example, 80% by weight or less.

  On the other hand, solder joint materials containing a large amount of solder are known. The solder joint material is, for example, a solder paste. The content of solder particles in the solder joint material exceeds, for example, 80% by weight.

  In order to obtain various connection structures, for example, the solder bonding material includes a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), and a connection between a semiconductor chip and a flexible printed circuit board (COF (Chip on)). Film)), connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)), and the like.

  When the electrodes are electrically connected, the solder joint material is selectively applied onto the electrodes that are soldered portions of the circuit board, for example, by screen printing or the like. Next, a semiconductor chip or the like is stacked, the solder is melted, and then solidified. The electrodes are electrically connected by the solidified solder.

  As an example of the anisotropic conductive material, Patent Document 1 described below describes an anisotropic conductive material including conductive particles and a resin component that cannot be cured at the melting point of the conductive particles. Specifically, the conductive particles include tin (Sn), indium (In), bismuth (Bi), silver (Ag), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd ), Metals such as gallium (Ga) and thallium (Tl), and alloys of these metals.

  In Patent Document 1, a resin heating step for heating the anisotropic conductive resin to a temperature higher than the melting point of the conductive particles and at which the curing of the resin component is not completed, and a resin component curing step for curing the resin component The electrical connection between the electrodes is described. Patent Document 1 describes that mounting is performed with the temperature profile shown in FIG. In Patent Document 1, the conductive particles melt in a resin component that is not completely cured at a temperature at which the anisotropic conductive resin is heated.

  In the following Patent Document 2, a solder paste containing solder particles and a flux is disclosed. The flux includes 1.0% by mass or more and less than 2.0% by mass of polyalkyl methacrylate and 5.0% by mass or more and less than 15.0% by mass of stearamide. The solder paste has a viscosity of 50 to 150 Pa · s. The flux is desirably decomposed or evaporated by heating during soldering and does not remain as a residue.

JP 2004-260131 A JP 2013-132654 A

  In the conventional anisotropic conductive material and solder joint material, the conductive particles or solder particles may not be efficiently arranged between the upper and lower electrodes to be connected.

  In addition, with regard to solder joint materials, in recent years, the width of electrodes with electrodes or the width between electrodes without electrodes has become narrower, and solder paste, etc. is selected only on one electrode that is the soldering part by screen printing or the like. It is becoming difficult to apply it. For this reason, it is assumed that the solder paste is applied so as to straddle a plurality of electrodes adjacent in the lateral direction. However, in this case, a plurality of electrodes adjacent in the horizontal direction are electrically connected by solder, and insulation failure is likely to occur.

  In particular, in the anisotropic conductive material in which the content of solder particles is 80% by weight or less, the plurality of electrodes adjacent in the horizontal direction are difficult to be electrically connected by solder, whereas the content of solder particles is low. In a solder paste exceeding 80% by weight, a plurality of electrodes adjacent in the horizontal direction are easily electrically connected by solder. When the solder paste is used, there is a problem that insulation failure is particularly likely to occur when the electrode width or the inter-electrode width is narrow.

  An object of the present invention is to enable solder to be efficiently arranged between electrodes to be connected even when the electrode width or the inter-electrode width is narrow, and to improve the conduction reliability and the insulation reliability. Is to provide materials. Another object of the present invention is to provide a connection structure using the solder joint material and a method for manufacturing the connection structure.

  According to a wide aspect of the present invention, a solder containing solder particles, a flux, and a binder, the content of the solder particles exceeds 80% by weight, and the solder particles have an amino group or a thiol group on the outer surface. There is provided a solder joint material containing particles or containing a compound having an amino group or a thiol group as at least one of the flux and the binder.

  In a specific aspect of the solder joint material according to the present invention, the solder joint material contains a compound having an amino group or a thiol group as at least one of the flux and the binder.

  In a specific aspect of the solder joint material according to the present invention, the compound having an amino group or a thiol group has an amino group or a thiol group at a molecular end.

  In a specific aspect of the solder joint material according to the present invention, the compound having an amino group or a thiol group is liquid at 25 ° C.

  In a specific aspect of the solder joint material according to the present invention, the compound having an amino group or a thiol group has a polyether skeleton.

  In a specific aspect of the solder joint material according to the present invention, at least one of a decomposition temperature and a volatilization temperature of the compound having an amino group or a thiol group is a melting point of the solder particles of −45 ° C. or higher and 260 ° C. or lower. is there.

  In a specific aspect of the solder joint material according to the present invention, at least one of a decomposition temperature and a volatilization temperature of the compound having an amino group or a thiol group is not lower than the melting point of the solder particle and not higher than 260 ° C.

  In a specific aspect of the solder joint material according to the present invention, the solder joint material includes a compound having a thiol group as the compound having an amino group or a thiol group.

  In a specific aspect of the solder joint material according to the present invention, the solder joint material includes a compound having an amino group and a compound having a thiol group as the compound having an amino group or a thiol group.

  On the specific situation with the soldering material which concerns on this invention, the boiling point of the said flux is 180 degreeC or more and 260 degrees C or less.

  In a specific aspect of the solder joint material according to the present invention, the solder particles have a carboxyl group on the outer surface.

  In a specific aspect of the solder joint material according to the present invention, the solder joint material is a solder paste, and includes a first connection target member having a plurality of first electrodes on a surface and a plurality of second electrodes. Used for electrical connection between the first electrode and the second electrode in the second connection target member on the surface, on the first electrode, more laterally than the first electrode. It is applied so as to protrude, or is applied so as to straddle the plurality of first electrodes on the plurality of first electrodes.

  According to a wide aspect of the present invention, a first connection target member having at least one first electrode on the surface, a second connection target member having at least one second electrode on the surface, and the first A solder portion connecting the second connection target member and the second connection target member, and the material of the solder portion is the above-described solder joint material, and the first electrode and the second electrode Are connected to each other by the solder portion.

  In a specific aspect of the connection structure according to the present invention, the first connection target member includes a plurality of the first electrodes, and the second connection target member includes a plurality of the second electrodes. However, the solder portion does not straddle between the adjacent first electrodes, and the solder portion does not straddle between the adjacent second electrodes.

  According to a wide aspect of the present invention, the step of disposing the above-described solder joint material on the surface of the first connection target member having at least one first electrode on the surface, and the first of the solder joint material. On the surface opposite to the connection target member, a second connection target member having at least one second electrode on the surface is disposed so that the first electrode and the second electrode face each other. Forming a solder portion connecting the first connection target member and the second connection target member by the solder bonding material by heating to a temperature equal to or higher than the melting point of the solder particles; and There is provided a method for manufacturing a connection structure comprising a step of electrically connecting the first electrode and the second electrode by the solder portion.

  On the specific situation with the manufacturing method of the connection structure which concerns on this invention, the said solder joint material is a solder paste, The said 1st connection object member has two or more said 1st electrodes, Said 2nd The connection target member has a plurality of the second electrodes, and the solder bonding material is arranged on the first electrode so as to protrude laterally from the first electrode, or a plurality The solder joint material is disposed on the first electrode so as to straddle between the adjacent first electrodes, and the solder portion does not straddle between the adjacent first electrodes, and Then, a connection structure in which the solder part does not straddle between the adjacent second electrodes is obtained.

  In a specific aspect of the method for manufacturing a connection structure according to the present invention, the solder joint material contains a compound having an amino group or a thiol group as at least one of the flux and the binder, and the solder particles And heating to at least one of the decomposition temperature and volatilization temperature of the compound having an amino group or a thiol group, thereby heating the first connection target member and the first The solder part which connects 2 connection object members is formed with the said solder joint material, and the said 1st electrode and the said 2nd electrode are electrically connected by the said solder part.

  The solder joint material according to the present invention includes solder particles, a flux, and a binder, and the content of the solder particles exceeds 80% by weight, and the solder particles have an amino group or a thiol group on the outer surface. Since it contains particles or a compound having an amino group or a thiol group as at least one of the flux and the binder, even if the electrode width or interelectrode width is narrow, the electrodes to be connected In addition, the solder can be arranged efficiently, and the conduction reliability and the insulation reliability can be improved.

FIG. 1 is a cross-sectional view schematically showing a connection structure obtained using a solder joint material according to an embodiment of the present invention. 2A to 2C are cross-sectional views for explaining each step of an example of a method for manufacturing a connection structure using a solder joint material according to an embodiment of the present invention. FIGS. 3A to 3C are cross-sectional views for explaining each step of another example of a method for manufacturing a connection structure using a solder joint material according to an embodiment of the present invention.

  Details of the present invention will be described below.

(Solder joint material)
The solder joint material according to the present invention includes solder particles, a flux, and a binder. In the solder joint material according to the present invention, the content of the solder particles exceeds 80% by weight. The solder joint material according to the present invention contains solder particles having amino groups or thiol groups on the outer surface as the solder particles, or amino groups or thiol groups as at least one of the flux and the binder. Containing a compound having The solder joint material according to the present invention may contain solder particles having an amino group or a thiol group on the outer surface as the solder particles, and an amino group or a thiol as at least one of the flux and the binder. A compound having a group may be contained. The solder joint material according to the present invention contains solder particles having amino groups or thiol groups on the outer surface as the solder particles, and an amino group or thiol group as at least one of the flux and the binder. You may contain the compound which has.

  In the present invention, since the above-described configuration is provided, even if the electrode width (line) with an electrode is narrow or the width (space) between electrodes without an electrode is narrow, the solder between the electrodes to be connected Can be arranged efficiently, and conduction reliability and insulation reliability can be improved. When the electrode width or the inter-electrode width is narrow, it tends to be difficult to collect the solder on the electrodes. However, in the present invention, even if the electrode width or the inter-electrode width is narrow, the solder can be sufficiently collected on the electrodes. it can. In the present invention, since the above configuration is provided, when the electrodes are electrically connected, the solder is likely to gather between the upper and lower electrodes, and the solder is efficiently arranged on the electrodes (lines). can do. Also, in the present invention, when an electrode has a wide electrode width, the solder is more efficiently arranged on the electrode. In the present invention, when the interelectrode width without electrodes is wide, the insulation reliability between the electrodes adjacent in the lateral direction is further increased.

  Further, in the present invention, a part of the solder is difficult to be disposed in a region (space) where no electrode is formed, and the amount of solder disposed in a region where no electrode is formed can be considerably reduced. In the present invention, the solder that is not located between the opposing electrodes can be efficiently moved between the opposing electrodes. Therefore, the conduction reliability between the electrodes can be improved. In addition, it is possible to prevent electrical connection between the laterally adjacent electrodes that should not be connected, and to improve the insulation reliability.

  Moreover, the solder joint material according to the present invention may be selectively disposed on one electrode or may be disposed so as to straddle a plurality of electrodes adjacent in the lateral direction. In recent years, the width of electrodes or the width between electrodes has become narrower, and it has become difficult to selectively apply a solder paste or the like only to one electrode that is a soldering portion by screen printing or the like. For this reason, it is assumed that the solder paste is applied so as to straddle a plurality of electrodes adjacent in the horizontal direction, and as a result, the plurality of electrodes adjacent in the horizontal direction are easily electrically connected by solder. Yes. In particular, in a solder paste in which the content of solder particles exceeds 80% by weight, there is a problem that a plurality of electrodes adjacent in the lateral direction are easily electrically connected by solder. In the present invention, it is possible to effectively prevent a plurality of electrodes adjacent in the horizontal direction from being electrically connected by solder. In the present invention, even when a solder bonding material (solder paste or the like) is applied so as to straddle a plurality of electrodes adjacent in the lateral direction, the solder moves efficiently between the upper and lower electrodes, and as a result Can be effectively prevented from being electrically connected by solder.

  Furthermore, in the present invention, it is possible to prevent positional deviation between the electrodes. In the present invention, when the second connection target member is superimposed on the first connection target member having the solder bonding material disposed on the upper surface, the electrode of the first connection target member and the electrode of the second connection target member Even when the first connection target member and the second connection target member are overlapped with each other in a state where the alignment is shifted, the shift is corrected and the electrode of the first connection target member and the second connection are corrected. The electrode of the target member can be connected (self-alignment effect).

  From the viewpoint of efficiently arranging solder between the upper and lower electrodes, the solder joint material preferably contains a compound having an amino group or a thiol group as at least one of the flux and the binder. The solder joint material may contain a compound having an amino group or a thiol group as the flux, and may contain a compound having an amino group or a thiol group as the binder. The solder joint material may contain a compound having an amino group or a thiol group as the flux, and may contain a compound having an amino group or a thiol group as the binder.

  The compound having an amino group or thiol group may not be a thermosetting compound, may not be a photocurable compound, may not be a thermosetting agent, and may not be a photopolymerization initiator.

  From the viewpoint of efficiently arranging the solder between the upper and lower electrodes, the compound having an amino group or thiol group preferably has an amino group or a thiol group at the molecular end. The compound having an amino group or a thiol group preferably has an amino group or a thiol group at the molecular terminal out of the molecular terminal and the molecular side chain. If an amino group or a thiol group is present at the molecular end, the amino group or thiol group tends to promote the movement of the solder particles between the upper and lower electrodes.

  From the viewpoint of efficiently arranging solder between the upper and lower electrodes, the compound having an amino group or a thiol group is preferably liquid at 25 ° C.

  From the viewpoint of efficiently arranging the solder between the upper and lower electrodes, the compound having an amino group or a thiol group preferably has a polyether skeleton.

  From the viewpoint of efficiently arranging the solder between the upper and lower electrodes, at least one of the decomposition temperature and volatilization temperature of the compound having an amino group or thiol group has a melting point of the solder particles of −50 ° C. or higher and 260 ° C. Preferably, the melting point of the solder particles is −45 ° C. or higher and 260 ° C. or lower, more preferably the melting point of the solder particles is −38 ° C. or higher and 260 ° C. or lower, and the solder particles are It is even more preferable that the melting point is 260 ° C. or higher. It is particularly preferable that at least one of the decomposition temperature and the volatilization temperature is the melting point of the solder particles + 5 ° C. or more, and most preferably the melting point of the solder particles + 10 ° C. or more. The lower one of the decomposition temperature and the volatilization temperature is preferably a melting point of the solder particles of −50 ° C. or higher, more preferably a melting point of the solder particles of −45 ° C. or higher. The melting point is more preferably −38 ° C. or more, even more preferably the melting point of the solder particles or more, particularly preferably the melting point of the solder particles + 5 ° C. or more, and the melting point of the solder particles + 10 ° C. or more. Most preferably it is. By using such a compound having an amino group or thiol group, it is possible to remove the compound having an amino group or thiol group after soldering and reduce the residue of the compound having an amino group or thiol group. An adverse effect due to a compound having a group or a thiol group can be prevented.

  The compound having an amino group or a thiol group may have an amino group, may have a thiol group, or may have an amino group and a thiol group. From the viewpoint of efficiently arranging solder between the upper and lower electrodes, the solder joint material may include a compound having an amino group and a compound having a thiol group as the compound having an amino group or a thiol group. preferable.

  From the viewpoint of efficiently arranging the solder between the upper and lower electrodes, the total content of the compound having an amino group or thiol group is preferably 2% by weight or more, more preferably, in 100% by weight of the solder joint material. Is 5% by weight or more, preferably less than 20% by weight, more preferably 17% by weight or less. From the viewpoint of efficiently arranging the solder between the upper and lower electrodes, the total content of the compound having an amino group or thiol group is preferably 10 in 100% by weight of the component excluding the solder particles in the solder joint material. % By weight or more, more preferably 25% by weight or more, preferably 90% by weight or less, more preferably 80% by weight or less.

  From the viewpoint of efficiently arranging the solder between the upper and lower electrodes, the total content of the compound having an amino group is preferably 1% by weight or more, more preferably 5% by weight in 100% by weight of the solder joint material. % Or more, preferably less than 20% by weight, more preferably 15% by weight or less. From the viewpoint of efficiently arranging the solder between the upper and lower electrodes, the total content of the compound having an amino group is preferably 5% by weight or more in 100% by weight of the component excluding the solder particles in the solder joint material. More preferably, it is 25% by weight or more, preferably 90% by weight or less, more preferably 80% by weight or less.

  From the viewpoint of efficiently arranging solder between the upper and lower electrodes, the total content of the compound having a thiol group is preferably 2% by weight or more, more preferably 3% in 100% by weight of the solder joint material. % Or more, more preferably 4% by weight or more, particularly preferably 5% by weight or more, preferably 23% by weight or less, more preferably 21% by weight or less, still more preferably 20% by weight or less, and still more preferably 18% by weight. % Or less, particularly preferably 17% by weight or less, and most preferably 16% by weight or less. From the viewpoint of efficiently arranging the solder between the upper and lower electrodes, the total content of the compound having a thiol group is preferably 10% by weight or more in 100% by weight of the component excluding the solder particles in the solder joint material. More preferably, it is at least 15% by weight, even more preferably at least 20% by weight, even more preferably at least 25% by weight, particularly preferably at most 90% by weight, more preferably at most 80% by weight.

  From the viewpoint of efficiently arranging solder between the upper and lower electrodes, the content of the compound having a thiol group in the solder joint material is preferably larger than the content of the compound having an amino group. From the viewpoint of efficiently arranging solder between the upper and lower electrodes, the content of the compound having the thiol group and the content of the compound having the amino group in 100% by weight of the solder bonding material in the solder bonding material. The absolute value of the difference from the amount is preferably 1% by weight or more, more preferably 3% by weight or more. From the viewpoint of efficiently arranging solder between the upper and lower electrodes, the content of the compound having the thiol group in 100% by weight of the solder bonding material excluding the solder particles in the solder bonding material, and the amino The absolute value of the difference from the content of the compound having a group is preferably 5% by weight or more, more preferably 15% by weight or more.

  The solder joint material can be used as a solder paste and a solder film. From the viewpoint of more efficiently arranging the solder on the electrode, the solder joint material is preferably a solder paste. The solder joint material is preferably used for electrical connection of electrodes. The solder joint material is preferably a circuit connection material.

  The solder bonding material includes the first electrode and the first electrode in the first connection target member having a plurality of first electrodes on the surface and the second connection target member having a plurality of second electrodes on the surface. It is preferably used for electrical connection with the two electrodes. Since the solder particles can be efficiently moved between the upper and lower electrodes, the solder joint material is applied on the first electrode so as to protrude laterally from the first electrode, Alternatively, it can be used by being applied on the plurality of first electrodes so as to straddle the plurality of first electrodes. However, the solder joint material may be applied and used so as not to straddle the plurality of first electrodes, or may be selectively applied and used on one of the first electrodes. .

  In order to arrange the solder more efficiently on the electrode, the solder joint material is preferably liquid at 25 ° C., and is preferably a solder paste. In order to arrange the solder more efficiently on the electrode, the viscosity (η25) at 25 ° C. of the solder joint material is preferably 50 Pa · s or more, more preferably 100 Pa · s or more, further preferably 150 Pa · s or more. In particular, it is 200 Pa · s or more, preferably 800 Pa · s or less, more preferably 600 Pa · s or less, even more preferably 500 Pa · s or less, still more preferably 400 Pa · s or less, and particularly preferably 300 Pa · s or less. Most preferably, it is 250 Pa · s or less. The viscosity (η25) can be appropriately adjusted depending on the type and amount of the compounding component.

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

  Hereinafter, each component contained in the solder joint material will be described.

(Solder particles)
The solder particles electrically connect the electrodes of the connection target member. The solder particles may be solder particles. The solder particles are formed of solder. As for the said solder particle, both the center part and the outer surface part of an electroconductive part are formed with the solder. The solder particles are particles in which both the central portion of the solder particles and the conductive outer surface are solder. The solder particles do not have base particles as core particles. The solder particles are different from conductive particles including base particles and solder portions arranged on the surfaces of the base particles. The solder particles contain, for example, solder preferably 90% by weight or more, more preferably 95% by weight or more.

  From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the solder particles preferably have a carboxyl group on the outer surface. A carboxyl group or an amino group is preferably present on the outer surface of the solder particle, preferably a carboxyl group is present, and an amino group is preferably present. In the solder particles, a group containing a carboxyl group or an amino group may be covalently bonded to the outer surface via a group represented by a Si—O bond, an ether bond, an ester bond, or the following formula (X). It is more preferable that a group containing a carboxyl group or an amino group is covalently bonded via an ether bond, an ester bond or a group represented by the following formula (X). The group containing a carboxyl group or an amino group may contain both a carboxyl group and an amino group. In the following formula (X), the right end and the left end represent a binding site.

  Hydroxyl groups exist on the surface of the solder. By covalently bonding this hydroxyl group and a group containing a carboxyl group, a stronger bond can be formed than in the case of bonding by other coordination bond (chelate coordination) or the like, so the connection resistance between the electrodes is reduced, And the solder particle which can suppress generation | occurrence | production of a void is obtained.

  In the solder particles, the bonding form between the surface of the solder and the group containing a carboxyl group may not include a coordination bond, and may not include a bond due to a chelate coordination.

  From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the solder particle is a compound having a functional group capable of reacting with a hydroxyl group and a carboxyl group or an amino group (hereinafter referred to as “a solder group”). It is preferably obtained by reacting a hydroxyl group on the surface of the solder with a functional group capable of reacting with the hydroxyl group. In the above reaction, a covalent bond is formed. By causing the hydroxyl group on the surface of the solder to react with the functional group capable of reacting with the hydroxyl group in the compound X, solder particles in which a group containing a carboxyl group or an amino group is covalently bonded to the surface of the solder can be easily obtained. It is also possible to obtain solder particles in which a group containing a carboxyl group or an amino group is covalently bonded to the surface of the solder via an ether bond or an ester bond. By reacting a hydroxyl group on the surface of the solder with a functional group capable of reacting with the hydroxyl group, the compound X can be chemically bonded to the surface of the solder in the form of a covalent bond.

  Examples of the functional group capable of reacting with the hydroxyl group include a hydroxyl group, a carboxyl group, an ester group, and a carbonyl group. A hydroxyl group or a carboxyl group is preferred. The functional group capable of reacting with the hydroxyl group may be a hydroxyl group or a carboxyl group.

  Examples of the compound having a functional group capable of reacting with a hydroxyl group include levulinic acid, glutaric acid, glycolic acid, succinic acid, malic acid, oxalic acid, malonic acid, adipic acid, 5-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, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, Hexadecanoic acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15) -linolenic acid, nonadecanoic acid, arachidic acid, decanedioic acid and dodecanedioic acid It is done. Glutaric acid or glycolic acid is preferred. Only 1 type may be used for the compound which has the functional group which can react with the said hydroxyl group, and 2 or more types may be used together. The compound having a functional group capable of reacting with the hydroxyl group is preferably a compound having at least one carboxyl group.

  The compound X preferably has a flux action, and the compound X preferably has a flux action in a state of being bonded to the solder surface. The compound having a flux action can remove the oxide film on the surface of the solder and the oxide film on the surface of the electrode. The carboxyl group has a flux action.

  Examples of the compound having a flux action include levulinic acid, glutaric acid, glycolic acid, succinic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, 4-aminobutyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3- Examples include methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, and 4-phenylbutyric acid. Glutaric acid or glycolic acid is preferred. As for the compound which has the said flux effect | action, only 1 type may be used and 2 or more types may be used together.

  From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the functional group capable of reacting with the hydroxyl group in the compound X is preferably a hydroxyl group or a carboxyl group. The functional group capable of reacting with the hydroxyl group in the compound X may be a hydroxyl group or a carboxyl group. When the functional group capable of reacting with the hydroxyl group is a carboxyl group, the compound X preferably has at least two carboxyl groups. By reacting a part of the carboxyl groups of the compound having at least two carboxyl groups with a hydroxyl group on the surface of the solder, solder particles in which a group containing a carboxyl group is covalently bonded to the surface of the solder can be obtained.

  The solder particle manufacturing method includes, for example, a step of using solder particles to mix the solder particles, a compound having a functional group capable of reacting with a hydroxyl group and a carboxyl group, a catalyst, and a solvent. In the method for producing solder particles, solder particles in which a group containing a carboxyl group is covalently bonded to the surface of the solder can be easily obtained by the mixing step.

  In the method for producing solder particles, it is preferable that the solder particles are used to mix and heat the solder particles, a compound having a functional group capable of reacting with the hydroxyl group and a carboxyl group, the catalyst, and the solvent. . By the mixing and heating process, solder particles in which a group containing a carboxyl group is covalently bonded to the surface of the solder can be obtained more easily.

  Examples of the solvent include alcohol solvents such as methanol, ethanol, propanol and butanol, acetone, methyl ethyl ketone, ethyl acetate, toluene and xylene. The solvent is preferably an organic solvent, and more preferably toluene. As for the said solvent, only 1 type may be used and 2 or more types may be used together.

  Examples of the catalyst include p-toluenesulfonic acid, benzenesulfonic acid and 10-camphorsulfonic acid. The catalyst is preferably p-toluenesulfonic acid. As for the said catalyst, only 1 type may be used and 2 or more types may be used together.

  It is preferable to heat at the time of the mixing. The heating temperature is preferably 90 ° C or higher, more preferably 100 ° C or higher, preferably 130 ° C or lower, more preferably 110 ° C or lower.

  From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the solder particles react with the isocyanate compound with the hydroxyl group on the surface of the solder using the isocyanate compound. It is preferable to be obtained through a process. In the above reaction, a covalent bond is formed. By reacting the hydroxyl group on the surface of the solder with the isocyanate compound, it is possible to easily obtain solder particles in which the nitrogen atom of the group derived from the isocyanate group is covalently bonded to the surface of the solder. By reacting the isocyanate compound with a hydroxyl group on the surface of the solder, a group derived from an isocyanate group can be chemically bonded to the surface of the solder in the form of a covalent bond.

  Moreover, a silane coupling agent can be easily reacted with a group derived from an isocyanate group. Since the solder particles can be easily obtained, the group containing a carboxyl group is introduced by a reaction using a silane coupling agent having a carboxyl group, or after a reaction using a silane coupling agent. It is preferably introduced by reacting a group derived from a silane coupling agent with a compound having at least one carboxyl group. The solder particles are preferably obtained by reacting the isocyanate compound with a hydroxyl group on the surface of the solder using the isocyanate compound and then reacting a compound having at least one carboxyl group.

  From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the compound having at least one carboxyl group preferably has a plurality of carboxyl groups.

  Examples of the isocyanate compound include diphenylmethane-4,4'-diisocyanate (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), and isophorone diisocyanate (IPDI). Isocyanate compounds other than these may be used. After reacting this compound on the surface of the solder, the surface of the solder is represented by the formula (X) by reacting the residual isocyanate group and a compound having reactivity with the residual isocyanate group and having a carboxyl group. A carboxyl group can be introduced through the group to be formed.

  As said isocyanate compound, you may use the compound which has an unsaturated double bond and has an isocyanate group. Examples include 2-acryloyloxyethyl isocyanate and 2-isocyanatoethyl methacrylate. After reacting the isocyanate group of this compound on the surface of the solder, reacting the compound having a functional group having reactivity with the remaining unsaturated double bond and having a carboxyl group, A carboxyl group can be introduced to the surface via a group represented by the formula (X).

  Examples of the silane coupling agent include 3-isocyanatopropyltriethoxysilane (“KBE-9007” manufactured by Shin-Etsu Silicone), 3-isocyanatepropyltrimethoxysilane (“Y-5187” manufactured by MOMENTIVE), and the like. As for the said silane coupling agent, only 1 type may be used and 2 or more types may be used together.

  Examples of the compound having at least one carboxyl group include levulinic acid, glutaric acid, glycolic acid, succinic acid, malic acid, oxalic acid, malonic acid, adipic acid, 5-ketohexanoic acid, 3-hydroxypropionic acid, 4-amino Butyric acid, 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, 3-methylthiopropionic acid, 3-phenylpropionic acid, 3-phenylisobutyric acid, 4-phenylbutyric acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecane Examples include acid, 9-hexadecenoic acid, heptadecanoic acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15) -linolenic acid, nonadecanoic acid, arachidic acid, decanedioic acid, and dodecanedioic acid. . Glutaric acid, adipic acid or glycolic acid is preferred. As for the compound which has at least 1 said carboxyl group, only 1 type may be used and 2 or more types may be used together.

  After reacting the isocyanate compound with the hydroxyl group on the surface of the solder using the isocyanate compound, reacting with a hydroxyl group on the surface of the solder by reacting a part of the carboxyl group of the compound having a plurality of carboxyl groups. Thus, a group containing a carboxyl group can be left.

  In the method for producing solder particles, using the solder particles and using an isocyanate compound, after reacting the isocyanate compound with a hydroxyl group on the surface of the solder, reacting a compound having at least one carboxyl group. Solder particles in which a group containing a carboxyl group is bonded to the surface of the solder via the group represented by the above formula (X) are obtained. In the method for producing solder particles, solder particles in which a group containing a carboxyl group is introduced on the surface of the solder can be easily obtained by the above-described steps.

  Specific methods for producing the solder particles include the following methods. Solder particles are dispersed in an organic solvent, and a silane coupling agent having an isocyanate group is added. Thereafter, a silane coupling agent is covalently bonded to the surface of the solder using a reaction catalyst between a hydroxyl group and an isocyanate group on the surface of the solder. Next, a hydroxyl group is produced | generated by hydrolyzing the alkoxy group couple | bonded with the silicon atom of a silane coupling agent. The produced hydroxyl group is reacted with a carboxyl group of a compound having at least one carboxyl group.

  Moreover, the following method is mentioned as a specific manufacturing method of the said solder particle. Solder particles are dispersed in an organic solvent, and a compound having an isocyanate group and an unsaturated double bond is added. Thereafter, a covalent bond is formed using a reaction catalyst of a hydroxyl group and an isocyanate group on the surface of the solder. Thereafter, the unsaturated double bond introduced is reacted with a compound having an unsaturated double bond and a carboxyl group.

  As reaction catalysts for hydroxyl groups and isocyanate groups on the solder surface, tin catalysts (dibutyltin dilaurate, etc.), amine catalysts (triethylenediamine, etc.), carboxylate catalysts (lead naphthenate, potassium acetate, etc.), and trialkyls A phosphine catalyst (triethylphosphine etc.) etc. are mentioned.

  From the viewpoint of effectively reducing the connection resistance in the connection structure and effectively suppressing the generation of voids, the compound having at least one carboxyl group is a compound represented by the following formula (1): Is preferred. The compound represented by the following formula (1) has a flux action. Moreover, the compound represented by following formula (1) has a flux effect | action in the state introduced into the surface of solder.

  In said formula (1), X represents the functional group which can react with a hydroxyl group, R represents a C1-C5 bivalent organic group. The organic group may contain a carbon atom, a hydrogen atom, and an oxygen atom. The organic group may be a divalent hydrocarbon group having 1 to 5 carbon atoms. The main chain of the organic group is preferably a divalent hydrocarbon group. In the organic group, a carboxyl group or a hydroxyl group may be bonded to a divalent hydrocarbon group. Examples of the compound represented by the above formula (1) include citric acid.

  The compound having at least one carboxyl group is preferably a compound represented by the following formula (1A) or the following formula (1B). The compound having at least one carboxyl group is preferably a compound represented by the following formula (1A), and more preferably a compound represented by the following formula (1B).

  In said formula (1A), R represents a C1-C5 bivalent organic group. R in the above formula (1A) is the same as R in the above formula (1).

  In said formula (1B), R represents a C1-C5 bivalent organic group. R in the above formula (1B) is the same as R in the above formula (1).

  A group represented by the following formula (2A) or the following formula (2B) is preferably bonded to the surface of the solder. A group represented by the following formula (2A) is preferably bonded to the surface of the solder, and more preferably a group represented by the following formula (2B) is bonded. In the following formula (2A) and the following formula (2B), the left end portion represents a binding site.

  In said formula (2A), R represents a C1-C5 bivalent organic group. R in the above formula (2A) is the same as R in the above formula (1).

  In said formula (2B), R represents a C1-C5 bivalent organic group. R in the above formula (2B) is the same as R in the above formula (1).

  From the viewpoint of improving the wettability of the solder surface, the molecular weight of the compound having at least one carboxyl group is preferably 10,000 or less, more preferably 1000 or less, and even more preferably 500 or less.

  The molecular weight means a molecular weight that can be calculated from the structural formula when the compound having at least one carboxyl group is not a polymer and when the structural formula of the compound having at least one carboxyl group can be specified. Further, when the compound having at least one carboxyl group is a polymer, it means a weight average molecular weight.

  It is preferable that the solder particles have a solder particle body and an anionic polymer disposed on the surface of the solder particle body because the cohesiveness of the solder particles can be effectively increased during the conductive connection. The solder particles are preferably obtained by surface-treating the solder particle body with an anionic polymer or a compound that becomes an anionic polymer. The solder particles are preferably a surface treated product of an anion polymer or a compound that becomes an anion polymer. As for the said anion polymer and the compound used as the said anion polymer, only 1 type may respectively be used and 2 or more types may be used together. The anionic polymer is a polymer having an acidic group.

  As a method of surface-treating the solder particle body with an anionic polymer, as an anionic polymer, for example, a (meth) acrylic polymer copolymerized with (meth) acrylic acid, synthesized from a dicarboxylic acid and a diol and having carboxyl groups at both ends Polyester polymer, polymer obtained by intermolecular dehydration condensation reaction of dicarboxylic acid and having carboxyl groups at both ends, polyester polymer synthesized from dicarboxylic acid and diamine and having carboxyl groups at both ends, and modified poval having carboxyl groups (Nippon Synthetic Chemical Co., Ltd. "GOHSEX T") etc., and the method of making the carboxyl group of an anionic polymer react with the hydroxyl group of the surface of a solder particle main body is mentioned.

Examples of the anion portion of the anion polymer include the carboxyl group, and other than that, a tosyl group (p-H ₃ CC ₆ H ₄ S (═O) ₂ —), a sulfonate ion group (—SO ₃ ^— ), And phosphate ion groups (—PO ₄ ⁻ ) and the like.

  As another method for the surface treatment, a compound having a functional group that reacts with a hydroxyl group on the surface of the solder particle body and further having a functional group that can be polymerized by an addition or condensation reaction is used. The method of polymerizing on the surface of a particle main body is mentioned. Examples of the functional group that reacts with the hydroxyl group on the surface of the solder particle body include a carboxyl group and an isocyanate group. Examples of the functional group that polymerizes by addition and condensation reactions include a hydroxyl group, a carboxyl group, an amino group, and (meth). An acryloyl group is mentioned.

  The weight average molecular weight of the anionic polymer is preferably 2000 or more, more preferably 3000 or more, preferably 10,000 or less, more preferably 8000 or less. When the weight average molecular weight is not less than the above lower limit and not more than the above upper limit, a sufficient amount of charge and flux properties can be introduced on the surface of the solder particles. Thereby, the cohesiveness of the solder particles can be effectively increased at the time of conductive connection, and the oxide film on the surface of the electrode can be effectively removed at the time of connection of the connection target member.

  When the weight average molecular weight is not less than the above lower limit and not more than the above upper limit, it is easy to dispose an anionic polymer on the surface of the solder particle main body, and the cohesiveness of the solder particles can be effectively enhanced during conductive connection. The solder can be more efficiently arranged on the electrode.

  The weight average molecular weight indicates a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

  The weight average molecular weight of the anionic polymer can be determined by measuring the weight average molecular weight of the remaining anionic polymer after dissolving the solder and removing the solder with dilute hydrochloric acid that does not cause decomposition of the anionic polymer.

  Regarding the introduction amount of the anionic polymer on the surface of the solder particles, the acid value per 1 g of the solder particles is preferably 1 mgKOH or more, more preferably 2 mgKOH or more, preferably 10 mgKOH or less, more preferably 6 mgKOH or less.

  The acid value can be measured as follows. 1 g of solder particles is added to 36 g of acetone and dispersed with an ultrasonic wave for 1 minute. Thereafter, phenolphthalein is used as an indicator and titrated with a 0.1 mol / L potassium hydroxide ethanol solution.

  The solder is preferably a metal (low melting point metal) having a melting point of 450 ° C. or lower. The low melting point metal is a metal having a melting point of 450 ° C. or lower. The melting point of the low melting point metal is preferably 300 ° C. or lower, more preferably 160 ° C. or lower. The solder preferably contains tin. In 100% by weight of the solder, the tin content is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 70% by weight or more, and particularly preferably 90% by weight or more. When the content of tin in the solder is not less than the above lower limit, the conduction reliability between the solder and the electrode is further enhanced.

  The tin content is determined using a high frequency inductively coupled plasma optical emission spectrometer (“ICP-AES” manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer (“EDX-800HS” manufactured by Shimadzu). It can be measured.

  By using the solder particles, the solder is melted and joined to the electrodes, and the solder conducts between the electrodes. For example, since the solder and the electrode are not in point contact but in surface contact, the connection resistance is lowered. In addition, the use of solder particles increases the bonding strength between the solder and the electrode. As a result, peeling between the solder and the electrode is further less likely to occur, and the conduction reliability is effectively increased.

  The low melting point metal is not particularly limited. The low melting point metal is preferably tin or an alloy containing tin. Examples of the alloy include a tin-silver alloy, a tin-copper alloy, a tin-silver-copper alloy, a tin-bismuth alloy, a tin-zinc alloy, and a tin-indium alloy. The low melting point metal is preferably tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, or a tin-indium alloy because of its excellent wettability with respect to the electrode. More preferred are a tin-bismuth alloy and a tin-indium alloy.

  The solder material is preferably a filler material having a liquidus of 450 ° C. or lower based on JIS Z3001: welding terms. Examples of the composition of the solder include a metal composition containing zinc, gold, silver, lead, copper, tin, bismuth, indium and the like. A tin-indium system (117 ° C eutectic) or a tin-bismuth system (139 ° C eutectic) that has a low melting point and is free of lead is preferable. That is, the solder preferably does not contain lead, and is preferably a solder containing tin and indium or a solder containing tin and bismuth.

  In order to further increase the bonding strength between the solder and the electrode, the solder may be nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth, manganese, chromium, molybdenum. Further, it may contain a metal such as palladium. Moreover, from the viewpoint of further increasing the bonding strength between the solder and the electrode, the solder preferably contains nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further increasing the bonding strength between the solder and the electrode, the content of these metals for increasing the bonding strength is preferably 0.0001% by weight or more, preferably 1% or more in 100% by weight of the solder. % By weight or less.

  The average particle diameter of the solder particles is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 3 μm or more, preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. When the average particle diameter of the solder particles is not less than the above lower limit and not more than the above upper limit, it is possible to more efficiently arrange the solder on the electrodes, and it is easy to dispose a lot of solder between the electrodes, and the conduction Reliability becomes even higher.

  The shape of the solder particles is not particularly limited. The solder particles may have a spherical shape or a shape other than a spherical shape such as a flat shape.

  In 100% by weight of the solder joint material, the content of the solder particles exceeds 80% by weight, preferably 81% by weight or more, more preferably 85% by weight or more, and further preferably 90% by weight or more, preferably 97 % By weight or less, more preferably 95% by weight or less, still more preferably 92% by weight or less. When the content of the solder particles is not less than the above lower limit and not more than the above upper limit, it is possible to more efficiently arrange the solder on the electrodes, and it is easy to dispose a lot of solder between the electrodes, and the conduction reliability The nature becomes even higher. From the viewpoint of further improving the conduction reliability, it is preferable that the content of the solder particles is large.

(binder)
The solder joint material preferably contains a compound having an amino group or a thiol group as at least one of the flux and the binder. The solder joint material preferably contains a compound having an amino group or a thiol group as the binder.

  Examples of the compound having an amino group or thiol group that can be used as the binder include a liquid polysulfide polymer, a reaction product of triallyl isocyanurate and dipentaerythritol hexakis (3-mercaptopropionate), polyether amine, and the like. Is mentioned.

  Examples of the binder other than the compound having an amino group or thiol group include polyether polyol and (meth) acrylic resin.

  In 100% by weight of the solder joint material, the content of the binder is preferably more than 1% by weight, more preferably 5% by weight or more, still more preferably 10% by weight or more, preferably less than 20% by weight, more preferably Is 17% by weight or less, more preferably 15% by weight or less. When the content of the binder is not less than the above lower limit and not more than the above upper limit, it is possible to more efficiently arrange the solder on the electrodes, and it is easy to arrange a lot of solder between the electrodes, and the conduction reliability Becomes even higher.

(flux)
The solder joint material preferably contains a compound having an amino group or a thiol group as at least one of the flux and the binder. The solder joint material preferably contains a compound having an amino group or a thiol group as the flux.

  By using flux, the solder can be more effectively placed on the electrode. The flux is not particularly limited. As the flux, a flux generally used for soldering or the like can be used.

  Examples of the compound having an amino group or thiol group that can be used as the flux include a reaction product of carboxylic acid and amine, a reaction product of carboxylic acid, aniline, and thiophenol.

  Examples of the flux include zinc chloride, a mixture of zinc chloride and an inorganic halide, a mixture of zinc chloride and an inorganic acid, a molten salt, phosphoric acid, a derivative of phosphoric acid, an organic halide, hydrazine, an organic acid, and pine resin. Etc. As for the said flux, only 1 type may be used and 2 or more types may be used together.

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

  The rosin is a rosin composed mainly of abietic acid. The flux is preferably rosins, and more preferably abietic acid. By using this preferable flux, the conduction reliability between the electrodes is further enhanced.

  The active temperature (melting point) of the flux is preferably 50 ° C. or higher, more preferably 70 ° C. or higher, still more preferably 80 ° C. or higher, preferably 200 ° C. or lower, more preferably 190 ° C. or lower, even more preferably 160. ° C or lower, more preferably 150 ° C or lower, still more preferably 140 ° C or lower. When the activation temperature of the flux is not less than the above lower limit and not more than the above upper limit, the flux effect is more effectively exhibited and the solder is more efficiently arranged on the electrode. The active temperature (melting point) of the flux is preferably 80 ° C. or higher and 190 ° C. or lower. The activation temperature (melting point) of the flux is particularly preferably 80 ° C. or higher and 140 ° C. or lower.

  The flux having an active temperature (melting point) of 80 ° C. or more and 190 ° C. or less includes succinic acid (melting point 186 ° C.), glutaric acid (melting point 96 ° C.), adipic acid (melting point 152 ° C.), pimelic acid (melting point 104 ° C.), dicarboxylic acids such as suberic acid (melting point 142 ° C.), benzoic acid (melting point 122 ° C.), malic acid (melting point 130 ° C.) and the like.

  Further, from the viewpoint of more efficiently arranging the solder on the electrode, the boiling point of the flux is preferably 200 ° C. or less.

  From the viewpoint of more efficiently arranging the solder on the electrode, the melting point of the flux is preferably higher than the melting point of the solder, more preferably 5 ° C or higher, and even more preferably 10 ° C or higher. .

  The flux may be dispersed in the solder bonding material, or may be attached on the surface of the solder particles.

  When the melting point of the flux is higher than the melting point of the solder, the solder can be efficiently aggregated on the electrode portion. This is because, when heat is applied at the time of joining, when the electrode formed on the connection target member is compared with the portion of the connection target member around the electrode, the thermal conductivity of the electrode portion is that of the connection target member portion around the electrode. Due to the fact that it is higher than the thermal conductivity, the temperature rise of the electrode portion is fast. At the stage where the melting point of the solder is exceeded, the inside of the solder is dissolved, but the oxide film formed on the surface does not reach the melting point (activation temperature) of the flux and is not removed. In this state, since the temperature of the electrode part first reaches the melting point (activation temperature) of the flux, the oxide film on the surface of the solder that has come preferentially on the electrode is removed, or the solder is activated by the activated flux. Since the surface charge is neutralized, the solder can spread on the surface of the electrode. Thereby, a solder can be efficiently aggregated on an electrode.

  In 100% by weight of the solder joint material, the content of the flux is preferably more than 1% by weight, more preferably 2% by weight or more, still more preferably 3% by weight or more, preferably less than 10% by weight, more preferably Is 8% by weight or less, more preferably 5% by weight or less. When the content of the flux is not less than the above lower limit and not more than the above upper limit, it becomes more difficult to form an oxide film on the surface of the solder and the electrode, and further, the oxide film formed on the surface of the solder and the electrode is more effective. Can be removed.

(Other ingredients)
The solder joint material may be, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, Various additives such as a lubricant, an antistatic agent and a flame retardant may be included.

(Connection structure and method of manufacturing connection structure)
A connection structure according to the present invention includes a first connection target member having at least one first electrode on the surface, a second connection target member having at least one second electrode on the surface, and the first And a solder part that connects the second connection target member. In the connection structure according to the present invention, the material of the solder portion is the solder joint material. The solder portion is formed of the solder joint material. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by the solder portion.

  In the connection structure according to the present invention, the first connection target member includes a plurality of the first electrodes, and the second connection target member includes a plurality of the second electrodes, and the adjacent ones. It is preferable that the solder portion does not straddle between the first electrodes, and the solder portion does not straddle between the adjacent second electrodes.

  In the manufacturing method of the connection structure according to the present invention, the step of disposing the above-described solder joint material on the surface of the first connection target member having at least one first electrode on the surface; The second connection target member having at least one second electrode on the surface opposite to the first connection target member is arranged such that the first electrode and the second electrode face each other. And a solder part connecting the first connection target member and the second connection target member by the solder bonding material by heating to a temperature equal to or higher than the melting point of the solder particles. And a step of electrically connecting the first electrode and the second electrode by the solder portion.

  In the method for manufacturing a connection structure according to the present invention, the solder bonding material may be arranged on the first electrode so as not to protrude to the side of the first electrode.

  In the method for manufacturing a connection structure according to the present invention, the solder joint material is preferably a solder paste. In the method for manufacturing a connection structure according to the present invention, the first connection target member has a plurality of the first electrodes, the second connection target member has a plurality of the second electrodes, The solder bonding material is disposed on the first electrode so as to protrude to the side of the first electrode, or the first electrodes adjacent to each other on the plurality of the first electrodes. The solder joint material is arranged so as to straddle the gap, the solder portion does not straddle between the adjacent first electrodes, and the solder portion straddles between the adjacent second electrodes. It is preferable to obtain an unconnected connection structure. The solder joint material may be disposed on the first electrode so as to protrude to the side of the first electrode, and the solder joint material may extend between the adjacent first electrodes. May be arranged.

  In the method for manufacturing a connection structure according to the present invention, the solder joint material contains a compound having an amino group or a thiol group as at least one of the flux and the binder, and is heated to a melting point or higher of the solder particles. And the first connection target member and the second connection target member by heating to at least one of the decomposition temperature and the volatilization temperature of the compound having an amino group or thiol group. It is preferable that the solder portion connecting the first electrode and the second electrode is electrically connected by the solder portion.

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

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

  A connection structure 1 shown in FIG. 1 includes a first connection target member 2, a second connection target member 3, and a solder that connects the first connection target member 2 and the second connection target member 3. Part 4. The solder part 4 is formed of the solder joint material described above.

  The first connection target member 2 has a plurality of first electrodes 2a on the surface (upper surface). The second connection target member 3 has a plurality of second electrodes 3a on the surface (lower surface). The first electrode 2 a and the second electrode 3 a are electrically connected by the solder portion 4. The solder part 4 does not straddle between the adjacent first electrodes 2a and between the adjacent second electrodes 3a.

  There is no solder in a region different from the solder portion 4 gathered between the first electrode 2a and the second electrode 3a. In an area different from the solder part 4, there is no solder separated from the solder part 4. If the amount is small, solder may be present in a region different from the solder portion 4 gathered between the first electrode 2a and the second electrode 3a.

  An underfill material may be filled in a region where there is no solder portion between the first connection target member and the second connection target member. Between the first connection target member and the second connection target member, a region without a solder portion may be filled with an underfill material and a connection structure may be used.

  From the viewpoint of further improving the conduction reliability, when the portion where the first electrode and the second electrode face each other in the stacking direction of the first electrode, the solder portion, and the second electrode is viewed, It is preferable that the solder portion is disposed in 50% or more (preferably 60% or more, more preferably 70% or more) of 100% of the area of the portion where the electrode and the second electrode face each other.

  Next, an example of a method for manufacturing the connection structure 1 using the solder joint material according to an embodiment of the present invention will be described.

  First, the 1st connection object member 2 which has the 1st electrode 2a on the surface (upper surface) is prepared. Next, as illustrated in FIG. 2A, the solder bonding material 11 including the solder particles 11 </ b> A is disposed on the surface of the first connection target member 2 (first step). A solder bonding material 11 including solder particles 11A is disposed on the first electrode 2a.

  The solder bonding material 11 is disposed on the surface of the first connection target member 2 on which the first electrode 2a is provided. In FIG. 2A, the solder bonding material 11 is selectively disposed on each first electrode 2a so as not to cross between the adjacent first electrodes 2a. The solder joint material 11 is arranged on one first electrode 2a so as to protrude to the side of the first electrode 2a. After the placement of the solder bonding material 11, the solder particles 11A are arranged both on the first electrode 2a (line) and on the region (space) where the first electrode 2a is not formed.

  The arrangement method of the solder bonding material 11 is not particularly limited, and examples thereof include application by a dispenser, screen printing, and discharge by an inkjet device.

  Moreover, the 2nd connection object member 3 which has the 2nd electrode 3a on the surface (lower surface) is prepared. Next, as shown in FIG. 2B, in the solder bonding material 11 on the surface of the first connection target member 2, on the surface opposite to the first connection target member 2 side of the solder bonding material 11. 2nd connection object member 3 is arranged (2nd process). On the surface of the solder bonding material 11, the second connection target member 3 is arranged from the second electrode 3a side. At this time, the first electrode 2a and the second electrode 3a are opposed to each other.

  Next, the solder bonding material 11 is heated to the melting point or higher of the solder particles 11A (third step). At the time of this heating, the solder particles 11A that existed in the region where no electrode is formed gather between the first electrode 2a and the second electrode 3a (self-aggregation effect). Also, the solder particles 11A are melted and joined together. Moreover, it is preferable that a binder decompose | disassembles or volatilizes by this heating. Furthermore, the flux is preferably decomposed or volatilized by this heating. As a result, as shown in FIG. 2C, the solder portion 4 that connects the first connection target member 2 and the second connection target member 3 is formed of the solder joint material 11. The solder part 4 is formed by joining a plurality of solder particles 11A.

  In addition, as shown to Fig.3 (a), you may arrange | position a solder bonding material selectively on each 1st electrode so that adjacent 1st electrode 2a may be straddled. In this case, a solder joint material may be arranged on one first electrode so as to protrude to the side of the first electrode. Then, you may obtain a connection structure through the state shown in Drawing 3 (b) and Drawing 3 (c) corresponding to Drawing 2 (b) and Drawing 2 (c).

  The heating temperature in the third step is preferably 140 ° C or higher, more preferably 160 ° C or higher, preferably 450 ° C or lower, more preferably 260 ° C or lower, still more preferably 250 ° C or lower, particularly preferably 200. It is below ℃.

  In addition, after the third step, the first connection target member or the second connection target member can be peeled from the solder portion for the purpose of correcting the position or re-manufacturing. The heating temperature for performing this peeling is preferably not lower than the melting point of the solder, more preferably not lower than the melting point (° C.) of the solder + 10 ° C. The heating temperature for performing this peeling may be the melting point of solder (° C.) + 100 ° C. or less.

  As a heating method in the third step, the entire connection structure is heated using a reflow furnace or an oven, or only the solder portion of the connection structure is locally heated above the melting point of the solder. The method of doing is mentioned.

  As a tool used for the method of heating locally, a hot plate, a heat gun for applying hot air, a soldering iron, an infrared heater, and the like can be given.

  In addition, when heating locally with a hot plate, the metal directly under the solder is made of a metal with high thermal conductivity, and other places where heating is not preferred are made of a material with low thermal conductivity such as a fluororesin. The upper surface of the hot plate is preferably formed.

  The said 1st, 2nd connection object member is not specifically limited. Specifically as said 1st, 2nd connection object member, electronic components, such as a semiconductor chip, a semiconductor package, LED chip, LED package, a capacitor | condenser, a diode, and a resin film, a printed circuit board, a flexible printed circuit board, flexible Examples include electronic components such as flat cables, rigid flexible substrates, glass epoxy substrates, and circuit boards such as glass substrates. The first and second connection target members are preferably electronic components.

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

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

Preparation method of binder 1:
Synthesis of compounds with thiol groups:
1 mol of triallyl isocyanurate (TAIC) was added to 3 mol of DPMP-E (dipentaerythritol hexakis (3-mercaptopropionate)) as radical initiator V-65 (manufactured by Wako Pure Chemical Industries, Ltd., azo polymerization started) The compound having a thiol group was synthesized by reacting at 60 ° C. for 30 minutes. The boiling point of the obtained compound having a thiol group was 190 ° C.

Preparation method of binder 2:
Synthesis of compounds having amino groups:
1 mol of triallyl isocyanurate (TAIC) is reacted with 3 radicals of bis (hexamethylene) triamine at 60 ° C. for 30 minutes with radical initiator V-65 (manufactured by Wako Pure Chemical Industries, Ltd., azo polymerization initiator). By doing so, a compound having an amino group was synthesized. The boiling point of the resulting compound having an amino group was 180 ° C.

Preparation method of binder 3:
Synthesis of compounds with thiol groups:
For 3 moles of TMTP (trimethylolpropane tristhiopropionate), 1 mole of triallyl cyanurate is reacted at 60 ° C. for 30 minutes with radical initiator V-65 (manufactured by Wako Pure Chemical Industries, Ltd., azo polymerization initiator). Thus, a compound having a thiol group was synthesized. The boiling point of the obtained compound having a thiol group was 170 ° C.

  Binder A: Hydrogenated rosin

Preparation method of flux 1:
30 parts by weight of tartaric acid and 75 parts by weight of benzylamine were placed in a three-necked flask and dissolved. Then, the flux 1 was obtained by making it react at 150 degreeC under pressure reduction (4 Torr or less) for 2 hours. The boiling point of the obtained flux 1 was 180 ° C.

  Flux A: Adipic acid

Method for producing solder particles 1:
Sn-3Ag-0.5Cu solder particles (“ST-5” manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter (median diameter) 5 μm) and citric acid (“Citric acid” manufactured by Wako Pure Chemical Industries, Ltd.) are used as a catalyst. Solder particles 1 in which a group containing a carboxyl group is covalently bonded to the surface of the solder by stirring for 8 hours while dehydrating in a toluene solvent at 90 ° C. using a certain p-toluenesulfonic acid (CV value 20%) Got. The melting point of the solder in the solder particles 1 was 218 ° C.

Method for producing solder particles 2:
200 g of Sn-3Ag-0.5Cu solder particles ("ST-5" manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter (median diameter) 5 m) and a silane coupling agent having an isocyanate group ("KBE-9007" manufactured by Shin-Etsu Silicone) ) 10 g and 70 g of acetone were weighed into a three-necked flask. While stirring at room temperature, 0.25 g of dibutyltin dilaurate, which is a reaction catalyst of the hydroxyl group and isocyanate group on the surface of the solder particles, was added, and the mixture was heated at 100 ° C. for 2 hours under stirring in a nitrogen atmosphere. Thereafter, 50 g of methanol was added, and the mixture was heated at 60 ° C. for 1 hour under stirring in a nitrogen atmosphere.

  Then, it cooled to room temperature, the solder particle was filtered with the filter paper, and the solvent removal was performed at room temperature by vacuum drying for 1 hour.

  The solder particles are put into a three-necked flask, 70 g of acetone, 30 g of trimethyl citrate, and 0.5 g of monobutyltin oxide that is a transesterification reaction catalyst are added, and the mixture is stirred at 60 ° C. under a nitrogen atmosphere. Reacted for hours.

  Thereby, the ester group of trimethyl citrate was reacted with the silanol group derived from the silane coupling agent by a transesterification reaction to be covalently bonded.

  Thereafter, 10 g of citric acid was added and reacted at 60 ° C. for 1 hour, whereby citric acid was added to the residual methyl ester group that had not reacted with the silanol group of trimethyl citrate.

  Then, cool to room temperature, filter the solder particles with filter paper, wash the solder particles with hexane on the filter paper, unreacted, and adhere to the surface of the solder particles by non-covalent bonds. After removing citric acid, the solvent was removed by vacuum drying at room temperature for 1 hour.

  After the obtained solder particles were crushed with a ball mill, a sieve was selected so as to obtain a predetermined CV value.

  Thereby, solder particles 2 (CV value 20%) were obtained. The melting point of the solder in the solder particles 2 was 218 ° C.

Method for producing solder particles 3:
Preparation of solder particles with thiol groups on the outer surface:
10 g of a thiol group-containing silane coupling agent (“KBM-803” manufactured by Shin-Etsu Silicone), 50 g of acetone and 20 g of water were weighed in a three-necked flask. While stirring at room temperature, the mixture was heated at 60 ° C. for 6 hours under a nitrogen atmosphere.

  Then, it cooled to room temperature, the solder particle was filtered with the filter paper, and the solvent removal was performed at room temperature by vacuum drying for 1 hour. Thereby, solder particles 3 (CV value 20%) were obtained. The melting point of the solder in the solder particles 3 was 218 ° C.

Method for producing solder particles 4:
Preparation of solder particles with amino groups on the outer surface:
10 g of a silane coupling agent having an amino group (“KBM-603” manufactured by Shin-Etsu Silicone), 50 g of acetone, and 20 g of water were weighed in a three-necked flask. While stirring at room temperature, the mixture was heated at 60 ° C. for 6 hours under a nitrogen atmosphere.

  Then, it cooled to room temperature, the solder particle was filtered with the filter paper, and the solvent removal was performed at room temperature by vacuum drying for 1 hour. Thereby, solder particles 4 (CV value 20%) were obtained. The melting point of the solder in the solder particles 4 was 218 ° C.

Method for producing solder particles 5:
Sn-3Ag-0.5Cu solder particles ("ST-5" manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter (median diameter) 5 [mu] m), SnBi solder particles, "ST-5" manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter (median) Solder particles 5 (CV value 20%) were obtained in the same manner as the solder particles 1 except that the diameter was changed to 5 μm). The melting point of the solder in the solder particles 5 was 139 ° C.

(CV value of solder particles)
The CV value was measured with a laser diffraction particle size distribution analyzer (“LA-920” manufactured by Horiba, Ltd.).

  Solder particles A: SnBi solder particles, melting point 139 ° C., “ST-5” manufactured by Mitsui Kinzoku Co., Ltd., average particle diameter (median diameter) 5 μm

  Diethylene glycol monohexyl ether

(Examples 1 to 7 and Comparative Examples 1 and 2)
(1) Preparation of solder paste The components shown in Table 1 below were blended in the blending amounts shown in Table 1 to obtain solder paste.

(2) Fabrication of connection structure After printing solder paste with a metal mask on the FR-4 substrate on which a plurality of copper foil lands are formed so as to straddle the plurality of copper foil lands, a 1005 size multilayer ceramic capacitor component Was mounted on a printed film of copper foil land by a mounter. Thereafter, reflow soldering was performed under the conditions of a maximum temperature of 260 ° C. and a holding time of 40 seconds, and a connection structure as a test substrate was produced.

(Evaluation)
(1) Viscosity The viscosity (η25) at 25 ° C. of the solder paste was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. and 5 rpm.

(2) Solder placement accuracy on electrode 1
In the obtained connection structure, when the portion where the first electrode and the second electrode face each other in the stacking direction of the first electrode, the solder portion, and the second electrode is viewed, The ratio X of the area where the solder portion is arranged in the area of 100% of the area facing the second electrode was evaluated. The solder placement accuracy 1 on the electrode was determined according to the following criteria.

[Criteria for solder placement accuracy 1 on electrode]
○○: Ratio X is 70% or more ○ 1: Ratio X is 65% or more and less than 70% ○ 2: Ratio X is 60% or more and less than 65% △ 1: Ratio X is 55% or more and less than 60% △ 2 : Ratio X is 50% or more and less than 55% X: Ratio X is less than 50%

(3) Confirmation of component mountability About the obtained connection structure, the presence or absence of a short circuit of 500 multilayer ceramic capacitors was confirmed.

  The results are shown in Table 1 below.

DESCRIPTION OF SYMBOLS 1 ... Connection structure 2 ... 1st connection object member 2a ... 1st electrode 3 ... 2nd connection object member 3a ... 2nd electrode 4 ... Solder part 11 ... Solder joint material 11A ... Solder particle

Claims (17)

Including solder particles, flux, and binder,
The solder particle content exceeds 80% by weight,
Solder joint containing solder particles having amino groups or thiol groups on the outer surface as the solder particles, or containing compounds having amino groups or thiol groups as at least one of the flux and the binder material.   The solder joint material according to claim 1, comprising a compound having an amino group or a thiol group as at least one of the flux and the binder.   The solder joint material according to claim 1 or 2, wherein the compound having an amino group or a thiol group has an amino group or a thiol group at a molecular end.   The solder joint material according to any one of claims 1 to 3, wherein the compound having an amino group or a thiol group is liquid at 25 ° C.   The solder joint material according to claim 1, wherein the compound having an amino group or a thiol group has a polyether skeleton.   6. The method according to claim 1, wherein at least one of a decomposition temperature and a volatilization temperature of the compound having an amino group or a thiol group is a melting point of the solder particles of −45 ° C. or more and 260 ° C. or less. Solder joint material.   The solder joint material according to claim 6, wherein at least one of a decomposition temperature and a volatilization temperature of the compound having an amino group or a thiol group is not lower than the melting point of the solder particles and not higher than 260 ° C.   The solder joint material according to any one of claims 1 to 7, comprising a compound having a thiol group as the compound having an amino group or a thiol group.   The solder joint material according to claim 8, comprising a compound having an amino group and a compound having a thiol group as the compound having an amino group or a thiol group.   The solder joint material according to claim 1, wherein the flux has a boiling point of 180 ° C. or higher and 260 ° C. or lower.   The solder joint material according to claim 1, wherein the solder particles have a carboxyl group on an outer surface. Solder paste,
Electricity between the first electrode and the second electrode in a first connection target member having a plurality of first electrodes on the surface and a second connection target member having a plurality of second electrodes on the surface Used for general connection,
The first electrode is applied so as to protrude laterally from the first electrode, or the plurality of first electrodes are applied so as to straddle the plurality of first electrodes. The solder joint material according to claim 1, wherein the solder joint material is used. A first connection target member having at least one first electrode on its surface;
A second connection target member having at least one second electrode on its surface;
A solder portion connecting the first connection target member and the second connection target member;
The material of the solder part is the solder joint material according to any one of claims 1 to 12,
A connection structure in which the first electrode and the second electrode are electrically connected by the solder portion. The first connection target member has a plurality of the first electrodes,
The second connection target member has a plurality of the second electrodes,
The connection structure according to claim 13, wherein the solder portion does not straddle between the adjacent first electrodes, and the solder portion does not straddle between the adjacent second electrodes. Disposing the solder joint material according to any one of claims 1 to 12 on the surface of the first connection target member having at least one first electrode on the surface;
On the surface opposite to the first connection target member of the solder joint material, a second connection target member having at least one second electrode on the surface, the first electrode and the second electrode And a step of arranging so as to face each other,
By heating to above the melting point of the solder particles, a solder portion connecting the first connection target member and the second connection target member is formed of the solder joint material, and the first The manufacturing method of a connection structure provided with the process of electrically connecting the electrode and said 2nd electrode with the said solder part. The solder joint material is a solder paste,
The first connection target member has a plurality of the first electrodes,
The second connection target member has a plurality of the second electrodes,
The solder bonding material is disposed on the first electrode so as to protrude to the side of the first electrode, or the first electrodes adjacent to each other on the plurality of first electrodes. Arrange the solder joint material so as to span
16. The connection structure according to claim 15, wherein the solder part does not straddle between the adjacent first electrodes and the solder part does not straddle between the adjacent second electrodes. A manufacturing method of a connection structure. The solder joint material contains a compound having an amino group or a thiol group as at least one of the flux and the binder,
By heating above the melting point of the solder particles, and heating to at least one of the decomposition temperature and volatilization temperature of the compound having an amino group or thiol group, the first connection target member And a solder part that connects the second connection target member with the solder joint material, and the first electrode and the second electrode are electrically connected by the solder part. The manufacturing method of the connection structure of Claim 15 or 16.

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