JP4676907B2 - Electronic component mounting structure using solder adhesive and solder adhesive - Google Patents

Description

  The present invention relates to a solder adhesive having excellent adhesive strength and an electronic component mounting structure using the solder adhesive.

  In recent years, when an electronic component is mounted on a substrate, a resin containing a metal powder has been used as a lead-free solder that does not contain lead as an environmental pollutant. In Patent Documents 2 and 3, an adhesive in which solder particles are dispersed is applied onto a substrate on which electrodes are pattern-printed, and another substrate is stacked and heated under pressure so that the electrodes are opposed to each other. A wiring substrate is disclosed in which metal particles are fused and aggregated between electrodes to perform electrical bonding.

  Patent Document 4 discloses a technique for performing solder connection by using an anisotropic conductive resin containing solder particles so as not to contact each other in an insulating resin, and simultaneously melting the resin by melting the solder particles. It is disclosed.

In Patent Document 1, in a paste solder adhesive composed of metal powder and a thermosetting resin, the metal and the thermosetting resin are selectively selected so that the melting point of the metal powder is lower than the curing temperature of the thermosetting resin. In combination with the above, a technique is disclosed in which the metal is melted before the thermosetting resin is cured, the conductor components in the paste are combined, and a conductive path is formed to increase the conductivity.
JP 2002-109956 A JP-A-60-178690 JP-A-61-174643 Japanese Patent Laid-Open No. 11-4064

  In Patent Document 1, a via hole formed in an insulating sheet is filled with a conductive paste to form a via hole conductor, then a wiring circuit layer is formed, and then a metal path is melted to form a conductive path. Although the curable resin is cured, the adhesive strength of the cured thermosetting resin to the wiring circuit layer and the conductive path is not sufficient, and the via hole conductor and the wiring circuit layer are peeled off by an external force. It was happening. If the content of the thermosetting resin is increased, it is possible to increase the adhesive force, but the content of the conductive particles is relatively lowered and the conductivity is impaired.

  The inventions disclosed in Patent Documents 2 to 4 also particularly increase the adhesive strength of the adhesive except that an adhesive containing solder particles and a resin is used for bonding between the substrate and the electronic component. There is no ingenuity.

  Further, in the methods described in Patent Document 2 and Patent Document 3, it is necessary to pressurize two substrates from both sides, which is limited to electrical bonding between sealed substrates, and solder bonding is performed on the substrates in an open system. I couldn't. In addition, there is a problem that metal particles are dispersed in the resin at portions other than the electrodes between the substrates, and the metal particles come into contact with each other and a short circuit is likely to occur.

  Also in Patent Document 4, since the solder particles are dispersed in the anisotropic conductive resin, there is a problem that a short circuit is likely to occur as in Patent Documents 2 and 3.

  Further, in order to improve the adhesive strength and electrical stability, it is necessary that the dispersibility of the solder particles in the adhesive is high, but each document does not particularly describe the dispersibility of the solder particles.

  In view of the above, an object of the present invention is to provide a solder adhesive having a high adhesive strength to a substrate or an electronic component, in which the adhesive strength of the thermosetting resin is enhanced without impairing the electrical conductivity of the solder particles.

The solder adhesive in the present invention contains solder particles and a thermosetting resin as main components, and 0.01 mass% or more and 1 mass% or less of silane with respect to the total mass of the solder particles, the resin and the curing agent. It contains a coupling agent, and by heating, the solder particles aggregate to form solder, and the resin flows out to form a resin layer .

  In the present invention, according to experiments described later, it is known that the adhesive strength can be improved by containing a silane coupling agent. Moreover, the dispersibility of the solder particles in the solder adhesive can be improved by the addition of the silane coupling agent, thereby improving the adhesive strength as well as the substrate and the electronic when used for bonding between the substrate and the electronic component. It has been found that the electrical conductivity between components can be increased and electrical stability can be improved.

  The solder particles are preferably made of tin-silver-copper (Sn-Ag-Cu) alloy particles. According to an experiment described later, by using particles of a tin-silver-copper (Sn-Ag-Cu) alloy as the solder particles, the adhesion can be appropriately performed as compared with the comparative example not containing the silane coupling agent. It has been found that the strength can be improved.

  Moreover, it is preferable that the said resin is a thermosetting resin, and when the thermosetting resin is an epoxy resin, it is excellent in adhesive force.

The content of the silane coupling agent, because within the above range, it is possible to increase more effectively the adhesive strength and the electrical conductivity.

The electronic component mounting structure in the present invention uses the solder adhesive described in any of the above for bonding between the substrate and the electronic component,
The electrode formed on the substrate and the terminal portion of the electronic component are solder-bonded, and at least a part of the periphery of the electronic component and the substrate are bonded by a resin layer. To do.

  Thereby, the adhesive strength between the solder and the resin layer, the resin layer and the electronic component, and the adhesive strength between the resin layer and the substrate can be improved. Can be improved. In addition, the conductivity between the electrode of the substrate and the terminal portion of the electronic component can be made good.

  Further, in the present invention, the solder adhesive is applied onto the electrode of the substrate before bonding, and by heating, the solder particles are aggregated between the electrode and the terminal portion, and the electrode and the terminal portion are solder-bonded. Preferably, the resin flows out to at least a part of the periphery of the electronic component, and at least a part of the periphery of the electronic component and the substrate are bonded by the resin layer. Conventionally, the substrate and the electronic component are bonded by, for example, hot pressing. However, in the present invention, it is not necessary to perform hot pressing, and it is simple and appropriate to apply and heat the solder adhesive on the electrode. In addition, the electrode and the terminal portion can be soldered together, and the periphery of the electronic component and the substrate can be bonded by a resin layer. As described above, in the present invention, the resin flows out to the periphery of the electronic component. At this time, the periphery of the electronic component is open, and in particular, there is nothing that inhibits the flow of the resin. A resin layer can be appropriately formed around the part. Further, in the present invention, the dispersibility of the solder particles is excellent by adding a silane coupling agent to the solder adhesive, thereby enabling appropriate solder bonding between the electrode and the terminal portion, Solder particles are less likely to remain inside the resin layer, and an electronic component mounting structure with excellent electrical stability can be provided.

  The solder adhesive of the present invention contains a silane coupling agent, which makes it excellent in adhesive strength and excellent in dispersibility of solder particles.

  The solder adhesive of the present invention is used for bonding between a substrate and an electronic component, whereby solder bonding can be performed between an electrode of the substrate and a terminal portion of the electronic component, and a part of the periphery of the electronic component and the substrate The gap can be adhered by a resin layer. At this time, since the silane coupling agent is included in the solder adhesive, the adhesive force between the solder and the resin layer, the adhesive force between the resin layer and the substrate, and the adhesive force between the resin layer and the electronic component are conventionally increased. Therefore, the adhesive strength between the substrate and the electronic component can be appropriately improved. In addition, the electrical conductivity between the electrode of the substrate and the terminal part of the electronic component can be made good.

  The solder adhesive of the present embodiment is a paste mainly composed of solder particles and a thermosetting resin, and contains a silane coupling agent. Then, by heating, the solder particles dissolve to form solder, and at the same time, the thermosetting resin flows out to the periphery to form an adhesive layer.

  As the solder particles contained in the solder adhesive, any metal particles can be used as long as they can form solder. In particular, an alloy mainly composed of tin (Sn) is preferably used. In this case, Sn accounts for 10% by mass or more, more preferably 40% by mass or more of the alloy. As a metal forming an alloy with Sn, silver (Ag), copper (Cu), nickel (Ni), bismuth (Bi), antimony (depending on the purpose of the melting point of the solder or the electrical conductivity) One type or two or more types can be selected from Sb), zinc (Zn), indium (In), lead (Pb), gold (Au), and germanium (Ge). For example, since silver and copper have high electrical conductivity, Sn—Ag, Sn—Cu, and Sn—Ag—Cu alloys form solder with high electrical conductivity, but have a high melting point of 200 to 250 ° C. In addition, the solder made of the Sn—Bi alloy has a low melting point of 60 to 200 ° C., is excellent in workability, and hardly causes thermal damage to the substrate or the electronic component. A trace amount of elements may be added to improve the metal structure of these solder alloys.

  In the present embodiment, the solder particles are preferably tin-silver-copper (Sn-Ag-Cu) alloy particles. According to experiments described later, it is known that when Sn—Ag—Cu is used as the solder particles, a large difference in adhesive strength occurs depending on the presence or absence of the silane coupling agent.

  The particle diameter of the solder particles is preferably 1 to 100 μm, more preferably 10 to 50 μm, particularly about 30 μm. Since the solder adhesive before application is in the form of a paste, the smaller the particle size of the solder particles in the paste, the better the dispersibility, and even when heated in a later process, it melts quickly to form solder. However, if the particle size is less than 1 μm, the particles are aggregated to reduce the dispersibility of the particles in the adhesive, and the surface of the solder particles is oxidized to prevent aggregation at the time of melting. Moreover, since it takes time and energy to produce particles having a small particle size, it is not economical to make particles smaller than necessary. If the particle size of the solder particles is larger than 100 μm, the dispersibility in the paste is poor and the particles are unevenly distributed, so the printability is poor, the solder amount at the joint is uneven, and the conductivity and adhesiveness of the formed solder are reduced. To do. Further, when heated in a later step, if the particles are large, it takes time to melt, which is not preferable. Further, the dispersibility can be improved by using spherical solder particles, and the cohesiveness at the time of melting can be improved by using flat solder particles.

  The content in the solder adhesive before applying the solder particles is preferably 50 to 90% by mass. If the solder particle content is less than 50% by mass, the electrical conductivity after heating is low, and defects occur in the solder joint after heating, which is not preferable. On the other hand, if the solder particle content is higher than 90% by mass, the resin content is relatively low, and the adhesive strength of the resin is weakened.

  The resin contained in the solder adhesive may be a resin other than a thermosetting resin such as an ultraviolet curable resin, but the thermosetting resin is preferably used because it is easy to use and easily obtains a predetermined adhesive strength. The As the thermosetting resin, an epoxy resin, a phenol resin, a melamine resin, a urea resin, or a polyester resin can be used, and particularly an epoxy resin because of excellent mechanical strength, chemical resistance, and adhesiveness. Resins are preferably used.

  The solder adhesive of this embodiment is mainly composed of solder particles and a thermosetting resin, and the content of solder particles in the solder adhesive is preferably 50 to 90% by mass as described above. Considering the content of the silane coupling agent, the preferable content of the thermosetting resin is about 5 to 50% by mass.

  When the thermosetting resin is heated, a polymerization reaction occurs and cures. However, when a curing agent is present, the reaction is accelerated and the resin is cured in a shorter time. It is also possible to change the properties of the resin obtained depending on the type of curing agent to be added. The curing agent is appropriately selected depending on the type of the thermosetting resin, and amines, polyamide resins, polymercaptans, acid anhydrides, and imidazole compounds can be used as the curing agent when using an epoxy resin. Furthermore, since a resin having high adhesive strength is obtained, an imidazole compound is more preferable.

  Since the curing agent promotes the curing of the thermosetting resin, it is preferable to adjust the addition amount as appropriate according to the curing temperature and curing time of the thermosetting resin. It is preferable to add about 10% by mass. When it is less than 1% by mass, the curing time of the thermosetting resin becomes too long, which is not preferable. Moreover, it may not be completely cured. If it is more than 10% by mass, the curing time is short, and it is not preferable because the resin is cured before heating or the thermosetting resin is cured before the solder particles are dissolved, and a solder joint is not formed.

  A curing agent is appropriately added to the thermosetting resin, and the solder particles are dispersed to obtain a paste-like solder adhesive, but in this embodiment, a silane coupling agent is further contained, thereby improving the adhesive strength. A high solder adhesive is obtained.

The silane coupling agent is a compound having a structure of X—R—Si ((CH ₃ ) _{3 -n} ) —Y _n as shown in Chemical Formula ₁ . Here, R is an alkylene group, and X is, for example, an epoxy group, amino group, vinyl group, styryl group, methacryloxy group, acryloxy group, ureido group, chloropropyl group, mercapto group, sulfide group, isocyanate group, etc. Y is an organic functional group that chemically bonds to an organic material such as a synthetic resin, and Y is a functional group that gives a silanol group (Si—OH) by hydrolysis, such as a chloro group, an alkoxy group, an acetoxy group, and an amino group. Since the silanol group is partially condensed into an oligomer state and adsorbed on the surface of the inorganic material by hydrogen bonding, the silane coupling agent has a high affinity with the surface of the inorganic material such as glass or metal. Table 1 shows examples of functional groups corresponding to R, X, and Y shown in Chemical formula 1.

  Thus, since the silane coupling agent has a high affinity with metals and organic materials, when the silane coupling agent is added to the solder adhesive composed of solder particles and thermosetting resin, the solder particles and the thermosetting resin The silane coupling agent acts at the interface, and the dispersibility of the solder particles in the paste is increased. Accordingly, since the solder particles are uniformly distributed when applied on the substrate, the heating can satisfactorily solder the electrode between the electrode of the substrate and the terminal part of the electronic component as described later, and the adhesive strength can be increased. In addition, the conductivity between the electrode and the terminal portion can be kept in a good state.

Any silane coupling agent may be used as long as it has a structure of X—R—Si ((CH ₃ ) _{3 -n} ) —Y _n as described above. In the case of an alkoxy group, since hydrolysis easily occurs, a methoxy group or an ethoxy group is preferable. In addition, when the thermosetting resin is an epoxy resin, when the organic functional group (-X) is an epoxy group or an amino group, the affinity between the thermosetting resin and the silane coupling agent is particularly high. Strength can be increased. In addition, depending on the material of the substrate used and the type of thermosetting resin, the organic functional group of the silane coupling agent is epoxy group, amino group, vinyl group, styryl group, methacryloxy group, acryloxy group, ureido group, chloropropyl group. By appropriately selecting from a mercapto group, a sulfide group, an isocyanate group, etc., between the solder and the thermosetting resin, and between the thermosetting resin and the substrate, the thermosetting resin and the electrode, or the thermosetting resin and the electronic component It is possible to improve the adhesive force between the two.

  The content of the silane coupling agent is from 0.01 to the total mass of the solder particles, the thermosetting resin and the curing agent (amount based on 100% by mass of the solder particles, the thermosetting resin and the curing agent). Add 1% by weight. If it is less than 0.01% by mass, the adhesive strength cannot be improved properly, and the dispersibility of the solder particles in the paste is poor, so the paste is not stable, and wetting when applied to an electrode, etc. It is not preferable because of its poor nature. When the content of the silane coupling agent is more than 5% by mass with respect to the total mass of the solder particles, the thermosetting resin and the curing agent, the silane coupling agent promotes the reaction of the thermosetting resin, and the viscosity change of the paste. Is undesirably large. Since the silane coupling agent is in a liquid state, immediately after the addition, the liquid content in the paste is excessive, and the coating properties and printability are deteriorated. And after 2 to 3 hours or more after addition, the viscosity becomes so high that printing or coating is difficult, or the thermosetting resin is cured before coating or before the solder particles melt, which is not preferable anyway. . Therefore, the content of the silane coupling agent is preferably less than 5% by mass. Furthermore, it is more preferable that content of a silane coupling agent is 0.05-1 mass% with respect to the total mass of a solder particle, a thermosetting resin, and a hardening | curing agent.

  The heating temperature for the solder adhesive can be set, for example, to a temperature at which the solder particles melt. At this time, the heating temperature may be lower than the thermosetting temperature of the thermosetting resin. For example, since the epoxy resin generates heat as the reaction proceeds, the epoxy resin can be appropriately heat-cured even if the heating temperature is lower than the thermosetting temperature. What is important is to prevent the thermosetting resin from thermosetting before the solder particles are melted and aggregated to form solder. Depending on the type of the thermosetting resin and the like, the optimum range is appropriately set.

  Next, a process of mounting an electronic component on a substrate using the solder adhesive of this embodiment will be described.

  FIG. 1 is a plan view of an electronic component mounting structure 1 in which an electronic component 4 is mounted on a substrate 2 using the solder adhesive of the present embodiment, and FIG. 2 is a plan view of the electronic component mounting structure shown in FIG. Sectional drawing of the said electronic component mounting structure 1 which cut | disconnected in the direction parallel to a height direction along the AA line and looked at the cut surface from the arrow direction is shown.

  The substrate 2 is an insulating substrate. In particular, when low-temperature solder is used as the solder adhesive, the substrate 2 can be formed of inexpensive polyethylene terephthalate (PET). Further, when the substrate 2 is required to have higher transparency, a polyethylene naphthalate (PEN) film can be used, and when the substrate 2 requires higher flame retardancy than PET, a polyimide film can be used. . Alternatively, a film in which a metal foil such as copper is attached using an adhesive and an electrode is formed by etching or the like can be used.

  An electrode 3 is formed on the substrate 2. The electrode 3 is formed, for example, in the form of a film having silver particles and a binder resin (polyester resin, phenol resin, etc.). The electrode 3 needs to have good solder wettability.

  As shown in FIGS. 1 and 2, a terminal portion 4 a of an electronic component 4 is joined to the electrode 3 via a solder layer 5. The solder layer 5 has, for example, a fillet shape as shown in FIG. The solder layer 5 is solidified in a state where solder particles contained in the solder adhesive are melted and agglomerated between the terminal portions 4 a and the electrodes 3. In general solder bonding, it is said that an object to be bonded and solder form an alloy, but in this embodiment, physical bonding is also included.

  As shown in FIG. 1, a resin layer 6 made of a thermosetting resin is formed around the electronic component 4 to bond the electronic component 4 and the substrate 2. The resin layer 6 is formed so as to surround the electronic component 4 from both sides of the solder layer 5 provided on the electrode 3. As shown in FIG. 2, it is preferable that the resin layer 6 is interposed between the lower surface 4 b of the electronic component 4 and the substrate 2 because the mounting strength between the electronic component 4 and the substrate 2 can be further improved.

  In the embodiment shown in FIGS. 1 and 2, the adhesive strength between the solder layer 5 and the resin layer 6, between the resin layer 6 and the substrate 2, and between the resin layer 6 and the electronic component 4 is between metal and organic material. It is higher due to the silane coupling agent having higher affinity. Therefore, in this embodiment, the adhesive strength between the substrate 2 and the electronic component 4 is appropriately higher than the conventional one. Moreover, since the solder layer 5 is formed by appropriately agglomerating the solder particles between the terminal portion 4a and the electrode 3 of the electronic component 4, the conductivity between the terminal portion 4a and the electrode 3 is excellent. In addition, since the resin layer 6 exists around the solder layer 5 and the upper surface of the solder layer 5 is partially covered with the resin layer 6, crystal growth of solder particles due to heating can be suppressed. The problem that a grain boundary is formed in the layer 5 and a crack etc. enter can be prevented appropriately.

  The solder layer 5 and the resin layer 6 shown in FIGS. 1 and 2 have at least the electrode 3 as the solder adhesive mixed before the heating step for melting the solder particles and further thermosetting the thermosetting resin. It is applied on top.

A method for manufacturing the electronic component mounting structure 1 shown in FIGS. 1 and 2 will be described.
The solder adhesive in this embodiment is applied onto the electrode 3 by metal mask printing or the like. Then, the electronic component 4 is installed at a predetermined position on the substrate 2. At this time, the terminal portion 4a of the electronic component 4 is opposed to the electrode 3 via the solder adhesive.

  Then, it heats to the melting temperature of a solder particle. When the Sn—Ag—Cu alloy is used as the conductive metal, the melting point is in the range of 240 to 250 ° C., so the heating temperature is 240 to 250 ° C.

  When the solder adhesive on the electrode 3 is heated, the solder particles contained in the solder adhesive are dissolved, and the solder layer 5 starts to aggregate between the electrode 3 and the terminal portion 4a. Thereafter, the solder layer 5 is solidified by being cooled to room temperature, and the terminal portion 4a of the electronic component 4 and the electrode 3 of the substrate 2 are appropriately soldered. On the other hand, the thermosetting resin contained in the solder adhesive is completely separated from the solder particles agglomerated on the electrode 3 during the heat treatment, and the periphery of the electronic component 4 and the electronic component from above the electrode 3. 4 flows out onto the substrate 2 below. The flowed-out thermosetting resin is then thermoset to form the resin layer 6 shown in FIGS.

  As described above, the electrode 3 of the substrate 2 and the terminal portion 4a of the electronic component 4 can be appropriately bonded by the solder layer 5, and the periphery of the electronic component 4 and the substrate 2 can be appropriately bonded by the resin layer 6.

  In this embodiment, since the solder adhesive contains a silane coupling agent, the affinity for metal and organic materials is increased, and the dispersibility of the solder particles contained in the solder adhesive is increased. I can do it. By using such a solder adhesive, the adhesive force between the solder layer 5 and the resin layer 6, between the resin layer 6 and the substrate 2, between the resin layer 6 and the electrode 3, and between the resin layer 6 and the electronic component 4 is appropriately set. Therefore, the adhesive strength between the substrate 2 and the electronic component 4 can be appropriately improved.

  Further, since the dispersibility of the solder particles in the solder adhesive is excellent, the solder particles can be appropriately aggregated between the terminal portion 4a and the electrode 3 in the heating step, and the solder layer 5 is interposed. The conductivity between the electrode 3 and the terminal portion 4a can be kept high.

  Conventionally, a solder adhesive is filled between the substrate 2 and the electronic component 4 and both are joined by hot pressing. However, in this embodiment, no hot pressing is required, and the solder adhesive on the electrode 3 is not required. The electronic component 4 and the substrate 2 can be solder-bonded and resin-bonded easily and appropriately by the coating and heating process.

  In the present embodiment, since the substrate 2 around the electronic component 4 on which the resin layer 6 and the solder layer 5 are formed is open, the aggregation of solder particles and the fluidity of the thermosetting resin are not impaired. The electrode 3 and the terminal portion 4a can be appropriately soldered together, and the solder particles are hardly left in the resin layer 6 (more preferably, the solder particles are not included at all). It can be improved appropriately.

  An electronic component mounting structure shown in FIG. 1 was prepared using a solder adhesive containing a silane coupling agent, and a conductivity test and an adhesive strength test were performed.

  The solder particles are Sn-Ag-Cu alloy particles (Sn96.5 / Ag3.0 / Cu0.5) with a particle diameter of 30 μm, and epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd.) as a thermosetting resin. Epicoat 828 ") and an imidazole compound were added as a curing agent to obtain a solder adhesive A containing 78 mass% solder particles, 21 mass% thermosetting resin, 1 mass% curing agent, and a total of 100 mass%.

  To the solder adhesive A, a silane coupling agent (“KBM-403” manufactured by Shin-Etsu Chemical Co., Ltd.) is added in an amount of 0.01% by mass with respect to the mass of the solder adhesive A. An agent was used.

  On the polyimide film with a thickness of 50 μm, the electrode was pattern printed using a paste in which 20% by mass of phenol resin was mixed with 80% by mass of copper powder coated with silver, and the phenol resin was cured by heating at 160 ° C. for 30 minutes. I let you. Using the dispenser, the solder adhesive of Example 1 was applied (printed) on the electrode, and a 1608 size jumper chip was arranged to connect the two electrodes. Thereafter, the solder component was melted by heating at 250 ° C. for 5 minutes to perform solder bonding, and the thermosetting resin was cured to obtain an electronic component mounting structure.

  As shown in Table 2, the addition amount of the silane coupling agent to the solder adhesive A is 0.05 mass% (Example 2), 0.5 mass% (Example 3), and 1 mass% (Example 4). The same electronic component mounting structure as that of Example 1 was prepared using the solder adhesive of each Example.

Comparative example

  Similarly, as shown in Table 2, an electronic component mounting structure was prepared in the same manner as in Example 1 except that the silane coupling agent was not added to the solder adhesive A (Comparative Example 1). Moreover, the solder adhesive which makes the addition amount of the silane coupling agent with respect to the solder adhesive A 5 mass% was created, and the same electronic component mounting structure as Example 1 was created (comparative example 2).

  Conductivity tests were conducted on the electronic component mounting structures obtained using the solder adhesives of Example 3 and Comparative Example 1. Furthermore, the adhesive strength measurement test was done about the electronic component mounting structure of Examples 1-4 and the comparative example 1. FIG.

  At room temperature, a current was passed between the electrodes 3 and 3 as shown in FIG. 3 to conduct a conductivity test, and the conductivity between the two electrodes was examined. The case where the electrodes 3 and 3 are electrically connected is indicated by 〇, and the case where the electrodes 3 and 3 are not electrically connected is indicated by ×.

Similarly, an adhesive strength measurement test as shown in FIG. 4 was performed at room temperature. Using the rod 7 having a width of 2 mm and a height of 5 mm, the mounted chip portion was pushed from the side at a speed of 5 mm / min, and the maximum strength when it was broken was measured to obtain an adhesive strength.
The results are summarized in Table 2.

  In both Example 3 and Comparative Example 1, it was found that the two electrodes had electrical conductivity, and the electrode-electronic component was well soldered. The adhesive strength of each example is 12.0 to 17.2 N, which is about 2 to 3 times the adhesive strength (6.5 N) of Comparative Example 1 using a solder adhesive to which no silane coupling agent is added. It was found that a solder adhesive containing a silane coupling agent showed high adhesive strength. From this, it was confirmed that the solder adhesive containing the silane coupling agent can increase the adhesive strength between the electronic component, the electrode and the substrate as compared with the case where the solder adhesive is not contained.

  Furthermore, the solder adhesive of Comparative Example 2 to which 5% by mass of the silane coupling agent was added had a viscosity that was too low immediately after the addition of the silane coupling agent, and could not be printed on the electrode. This time, the viscosity was so high that it could not be applied to the electrode, and the electronic component could not be mounted. Therefore, it is preferable that the addition amount of a silane coupling agent is less than 5 mass%. Further, considering the adhesive strength of the solder adhesive, the addition amount of the silane coupling agent is more preferably 0.05 to 1% by mass.

The top view which shows the mounting structure using the solder adhesive of this embodiment Sectional drawing of the mounting structure in the AA line shown in FIG. Schematic diagram showing the state of conductivity test of the mounting structure Schematic diagram showing the state of measurement test for adhesive strength of mounting structure

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic component mounting structure 2 Board | substrate 3 Electrode 4 Electronic component 4a Terminal part 5 Solder layer 6 Resin layer

Claims (6)

Solder particles and a resin as main components, containing 0.01% by mass or more and 1% by mass or less of a silane coupling agent with respect to the total mass of the solder particles, the resin and the curing agent , A solder adhesive , wherein solder particles aggregate to form solder, and the resin flows out to form a resin layer .   The solder adhesive according to claim 1, wherein the solder particles are particles of a tin-silver-copper (Sn—Ag—Cu) alloy.   The solder adhesive according to claim 1, wherein the resin is a thermosetting resin.   The solder adhesive according to claim 3, wherein the thermosetting resin is an epoxy resin. For bonding between the substrate and the electronic component, the solder adhesive according to any one of claims 1 to 4 is used,
The electrode formed on the substrate and the terminal portion of the electronic component are solder-bonded, and at least a part of the periphery of the electronic component and the substrate are bonded by a resin layer. Electronic component mounting structure. The solder adhesive is applied onto the electrode of the substrate before bonding, and by heating, the solder particles are aggregated between the electrode and the terminal portion to be soldered between the electrode and the terminal portion, and the resin is The electronic component mounting structure according to claim 5 , wherein the electronic component mounting structure flows out to at least a part of the periphery of the electronic component, and at least a part of the periphery of the electronic component and the substrate are bonded by the resin layer.

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