TWI669721B - Anisotropic conductive adhesive - Google Patents

Abstract

The present invention provides an anisotropic conductive adhesive which can attain high heat dissipation characteristics. The anisotropic conductive adhesive includes: conductive particles (31) having a conductive metal layer formed on a surface of the resin particles; solder particles (32) having an average particle diameter smaller than that of the conductive particles; and a binder that conducts electricity The particles (31) and the solder particles (32) are dispersed. At the time of pressure bonding, the conductive particles (31) are electrically connected to each other by flat deformation due to the pressing, and the terminals are welded by the solder particles (32) having an average particle diameter smaller than that of the conductive particles (31). The contact area between the opposing terminals is increased to obtain high heat dissipation characteristics.

Description

Anisotropic conductive adhesive

The present invention relates to an anisotropic conductive adhesive in which conductive particles are dispersed, and more particularly to a heat transfer capable of dissipating heat generated by a wafer (element) such as an LED (Light Emitting Diode) or a driver IC (Integrated Circuit). Conductive adhesive.

Conventionally, as a processing method for mounting an LED element on a substrate, a wire bond processing method has been used. As shown in FIG. 5, in the wire bonding method, the electrodes of the LED elements (the first conductive type electrode 104a and the second conductive type electrode 102a) face up, and the bonding wires (WB) 301a and 301b perform the bonding. The LED element is electrically bonded to the substrate, and the adhesive element 302 is used as the adhesion between the LED element and the substrate.

However, such a method of obtaining an electrical connection by using a bonding wire has a risk that the bonding wire is physically broken and peeled off from the electrode (the first conductive type electrode 104a and the second conductive type electrode 102a), so that a technique of higher reliability is sought. . Further, since the hardening process of the die bond 302 is performed by oven hardening, it takes time to produce.

As a processing method that does not use a bonding wire, as shown in FIG. 6, the electrode of the LED element (the first conductive type electrode 104a and the second conductive type electrode 102a) faces the substrate side (face down, flip-chip) The wafer is electrically connected to the substrate by using a conductive paste 303 typified by a silver paste.

However, since the adhesive force of the conductive paste 303 is weak, it is necessary to use a seal. Resin 304 is reinforced. Further, since the curing process of the sealing resin 304 is performed by oven hardening, it takes time to produce.

As a processing method in which the conductive paste is not used, there is a method in which the electrode surface of the LED element is directed toward the substrate side (face down, flip chip) as shown in FIG. 7 and dispersed by using an insulating adhesive 305. An anisotropic conductive adhesive having conductive particles 306 electrically connects the LED element to the substrate and then. The anisotropic conductive adhesive has a good production efficiency because the subsequent process is short. Further, the anisotropic conductive adhesive is inexpensive, and is excellent in transparency, adhesion, heat resistance, mechanical strength, electrical insulation, and the like.

Further, in recent years, LED elements for flip chip mounting have been developed. Since the LED element for the FC package can be designed to obtain a large electrode area by using the passivation material 105, a bumpless package can be realized. Further, since the reflective film is provided under the light-emitting layer, the light extraction efficiency is improved.

As a processing method for mounting the LED element for FC mounting on a substrate, as shown in FIG. 8, gold-tin eutectic bonding is used. The gold tin eutectic bonding is a processing method in which a wafer electrode is formed from an alloy 307 of gold and tin, a flux is applied onto a substrate, and a wafer is mounted and heated to perform eutectic bonding with the substrate electrode. However, such a solder joint processing method has an adverse effect on reliability due to wafer offset during heating or flux which is not completely washed out, and thus the yield is poor. Also, a high degree of construction technology is required.

As a processing method in which the gold tin eutectic is not used, there is a solder joint processing method in which the electrode surface of the LED element is electrically connected to the substrate using the conductive paste 303 as shown in FIG. However, in such a solder joint processing method, since the paste has an isotropic conductivity, the pn electrodes are short-circuited and the yield is poor.

As a processing method in which the solder paste is not used, as shown in FIG. 10, in the same manner as in FIG. 7, the LED element and the substrate are bonded using an anisotropic conductive adhesive such as ACE in which the conductive particles 306 are dispersed in an insulating adhesive. Electrical connection and then. The anisotropic conductive adhesive is filled with an insulating adhesive between the pn electrodes. Therefore, a short circuit is less likely to occur, so the yield is good. Moreover, since the subsequent process is short, the production efficiency is good.

In addition, the active layer (junction) 103 of the LED element generates a large amount of heat in addition to light. When the temperature of the light-emitting layer (Tj=junction temperature) reaches 100° C. or higher, the luminous efficiency of the LED is lowered, and the life of the LED is shortened. Therefore, a configuration for efficiently dissipating heat of the active layer 103 is required.

In the WB package shown in FIG. 5, the active layer 103 is located on the upper side of the LED element, so that the generated heat is not efficiently transmitted to the substrate side, and thus heat dissipation is inferior.

Further, when the flip chip mounting as shown in FIGS. 6 to 10 is performed, since the active layer 103 is positioned on the substrate side, heat is efficiently transferred to the substrate side. As shown in FIG. 6 and FIG. 9, when the electrodes are joined by the conductive paste 303, heat can be efficiently dissipated. However, the connection by the conductive paste 303 is poor in connection reliability as described above. Further, as shown in Fig. 8, in the case of performing gold-tin eutectic bonding, the connection reliability was also inferior in the same manner as described above.

Further, as shown in FIGS. 7 and 10, the conductive paste 303 is used, and the flip chip package is formed by an anisotropic conductive film such as ACF (Anisotropic conductive film) or ACP (Anisotropic Conductive Paste). The active layer 103 is disposed in the vicinity of the substrate side, and efficiently transfers heat to the substrate side. Moreover, since the adhesion force is high, high connection reliability can be obtained.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2005-120357

[Patent Document 2] Japanese Patent Laid-Open No. Hei 5-152464

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2003-026763

However, in the flip chip mounting of the LED element using the previous anisotropic conductive adhesive, since only the conductive particles of the electrical connection portion become the heat dissipation path, the heat generated from the LED element cannot be sufficiently dissipated. To the substrate side, high heat dissipation characteristics cannot be obtained.

The present invention has been made in view of such prior art, and provides an anisotropic conductive adhesive which can attain high heat dissipation characteristics.

As a result of intensive studies, the inventors of the present invention have found that the above objects can be attained by blending conductive particles in which a conductive metal layer is formed on the surface of the resin particles and solder particles having an average particle diameter smaller than that of the conductive particles, and the present invention has been completed.

That is, the anisotropic conductive adhesive of the present invention is characterized by comprising: conductive particles having a conductive metal layer formed on the surface of the resin particles; solder particles having an average particle diameter smaller than the conductive particles; and a binder; The conductive particles and the solder particles are dispersed.

Further, the connection structure according to the present invention includes: a first electronic component, a second electronic component, and an anisotropic conductive film, wherein the anisotropic conductive film uses the anisotropic conductive adhesive to bond the first electron The component is formed by the second electronic component, wherein the anisotropic conductive adhesive comprises: conductive particles, wherein a conductive metal layer is formed on the surface of the resin particle; and the solder particle has an average particle diameter smaller than the conductive particle; And a binder that disperses the conductive particles and the solder particles; and the terminal of the first electronic component of the connection structure system The terminal of the second electronic component is electrically connected to each other via the conductive particles, and is soldered by the solder particles.

According to the present invention, at the time of pressure bonding, the conductive particles are flatly deformed by the pressing, and the terminals are electrically connected to each other, and the solder is bonded between the terminals by the solder particles having an average particle diameter smaller than the conductive particles. The contact area is increased to obtain high heat dissipation characteristics.

11‧‧‧ element substrate

12‧‧‧1st conductive coating

12a‧‧‧1st conductive electrode

13‧‧‧Active layer

14‧‧‧2nd conductive coating

14a‧‧‧2nd conductive electrode

21‧‧‧Substrate

22‧‧‧Circuit pattern for the first conductivity type

23‧‧‧Circuit pattern for the second conductivity type

22a, 23a‧‧‧ electrodes

15‧‧‧ Passivation material

31‧‧‧Electrical particles

32‧‧‧ solder particles

33‧‧‧Binder

101‧‧‧ element substrate

102‧‧‧1st conductive coating

102a‧‧‧1st conductive electrode

103‧‧‧Active layer

104‧‧‧2nd conductive coating

104a‧‧‧2nd conductive electrode

105‧‧‧ Passivation material

201‧‧‧Substrate

202‧‧‧First conductive type circuit pattern

203‧‧‧2nd conductive type circuit pattern

301a, 301b‧‧‧ welding line

302‧‧‧Mack crystal

303‧‧‧ Conductive paste

304‧‧‧ sealing resin

305‧‧‧Binder

306‧‧‧Electrical particles

307‧‧‧Gold Tin Alloy

Fig. 1 is a cross-sectional view schematically showing a terminal between opposite terminals before crimping.

Fig. 2 is a cross-sectional view schematically showing the terminal between the opposite ends after crimping.

Fig. 3 is a cross-sectional view showing an example of an LED assembly according to an embodiment of the present invention.

Fig. 4 is a cross-sectional view showing an example of an LED package according to another embodiment of the present invention.

Fig. 5 is a cross-sectional view showing an example of an LED package obtained by the prior wire bonding method.

Fig. 6 is a cross-sectional view showing an example of an LED assembly using a conventional conductive paste.

Fig. 7 is a cross-sectional view showing an example of an LED package using a conventional anisotropic conductive adhesive.

Fig. 8 is a cross-sectional view showing an example of an LED package in which a conventional FC-structure LED is mounted by gold-tin eutectic bonding.

Fig. 9 is a cross-sectional view showing an example of an LED package in which a conventional FC package LED is mounted by a conductive paste.

Fig. 10 is a cross-sectional view showing an example of an LED assembly in which a conventional FC-structure LED is mounted by using an anisotropic conductive adhesive.

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

1. Anisotropic conductive adhesive

2. Connection structure and manufacturing method thereof

3. Embodiment

<1. Anisotropic conductive adhesive>

The anisotropic conductive adhesive in the present embodiment is obtained by dispersing conductive particles having a conductive metal layer on the surface of the resin particle and solder particles having an average particle diameter smaller than that of the conductive particles in a binder (adhesive component). The shape is a paste, a film, or the like, and may be appropriately selected depending on the purpose.

1 and 2 are schematic cross-sectional views showing the positions between the opposing terminals before and after crimping, respectively. As shown in FIG. 1 and FIG. 2, at the time of pressure bonding, the solder particles 32 having an average particle diameter smaller than that of the conductive particles 31 are crushed following the flat deformation of the conductive particles 31, and metal bonding is performed by welding by heating. Therefore, the area in contact with the terminal is increased, and the heat dissipation characteristics and electrical characteristics can be improved. When the solder particles 32 are larger than the conductive particles 31, there is a case where leakage occurs and the yield is deteriorated.

Further, at the time of pressure bonding, the conductive particles 31 are flatly deformed by the pressing force, and elastic rebound occurs with respect to the deformation, so that the electrical connection state can be maintained. Further, the conductive particles of the resin core alleviate the stress generated by the difference in thermal expansion between the substrate and the element, prevent cracking in the welded portion, and improve connection reliability.

The conductive particles are metal-coated resin particles in which a conductive metal layer is formed on the surface of the resin particles. Examples of the resin particles include an epoxy resin, a phenol resin, an acrylic resin, an acrylonitrile-styrene (AS) resin, and a benzoquinone. (benzoguanamine) resin, divinylbenzene resin, styrene resin, and the like. A metal that is a conductive metal layer. For example, Au, Ni, Ag, Zn, etc. are mentioned. Such metal-coated resin particles are easily crushed during compression and are easily deformed, so that the contact area with the wiring pattern can be increased. Moreover, the deviation of the height of the wiring pattern can be absorbed, and the connection reliability can be improved.

The average particle diameter of the conductive particles is preferably 1 μm or more and 10 μm or less, and more preferably 1 μm or more and 8 μm or less. In addition, the blending amount of the conductive particles is preferably 1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the binder from the viewpoint of connection reliability and insulation reliability.

The average particle diameter of the solder particles is smaller than that of the conductive particles, and it is preferable that the average particle diameter of the solder particles is 20% or more and less than 100% of the average particle diameter of the conductive particles. When the solder particles are too small with respect to the conductive particles, the solder particles are not caught between the opposing terminals during the pressure bonding, and metal bonding cannot be performed, so that excellent heat dissipation characteristics and electrical characteristics cannot be obtained. On the other hand, when the solder particles are excessively large with respect to the conductive particles, for example, collision occurs between the solder particles at the edge portion of the LED wafer, and leakage occurs, and the yield of the product is deteriorated.

The solder particles may be, for example, a Sn-Pb system, a Pb-Sn-Sb system, a Sn-Sb system, a Sn-Pb-Bi system, a Bi-Sn system, a Sn-Cu system, or a Sn-Pb as defined in JIS Z 3282-1999. The Cu-based, Sn-In-based, Sn-Ag-based, Sn-Pb-Ag-based, and Pb-Ag-based materials are appropriately selected depending on the electrode material, the connection conditions, and the like. Further, the shape of the solder particles can be appropriately selected from granular or scaly shapes. Further, in order to improve the anisotropy, the solder particles may be coated with an insulating layer.

The blending amount of the solder particles is preferably 1% by volume or more and 30% by volume or less. If the blending amount of the solder particles is too small, excellent heat dissipation characteristics cannot be obtained, and if the blending amount is too large, Lossworthy anisotropy and excellent connection reliability.

Moreover, it is preferable that the blending amount of the solder particles is 1% by volume or more and 30% by volume or less, and the blending amount of the conductive particles is 1% by volume or more and 20% by volume or less. By thus blending, the heat dissipation characteristics and connection reliability of the connection structure can be improved. Further, it is preferable that the amount of the solder particles blended is larger than the blend amount of the conductive particles. By making the amount of solder particles blended more than the amount of conductive particles blended, the anisotropy can be improved and the electrical characteristics can be improved.

Moreover, it is preferable that the blending amount of the solder particles is 10% by volume or more and 30% by volume or less, and the blending amount of the conductive particles is 1% by volume or more and 15% by volume or less, and the blending amount of the solder particles is larger than that of the conductive particles. Sex particles. By such blending, the thermal resistance value becomes small, and excellent heat dissipation characteristics can be obtained.

As the binder, a conventional anisotropic conductive adhesive or an adhesive composition used in an anisotropic conductive film can be used. As the adhesive composition, an epoxy curing adhesive containing a alicyclic epoxy compound, a heterocyclic epoxy compound, a hydrogenated epoxy compound or the like as a main component is preferably used.

As the alicyclic epoxy compound, those having two or more epoxy groups in the molecule are preferably exemplified. These may be liquid or solid. Specific examples thereof include glycidyl hexahydrobisphenol A, 3', 4'-epoxycyclohexenecarboxylic acid 3,4-epoxycyclohexenyl methyl ester, and the like. Among them, 3', 4'-epoxycyclohexenecarboxylic acid can be preferably used in terms of ensuring light transmittance suitable for the structure of the LED element and the like, and also excellent in rapid hardenability. 3,4-epoxycyclohexenylmethyl ester.

As the heterocyclic epoxy compound, there are three The epoxy compound of the ring, particularly preferably 1,3,5-tris(2,3-epoxypropyl)-1,3,5-three -2,4,6-(1H,3H,5H)-trione.

As the hydrogenated epoxy compound, a hydride of the above alicyclic epoxy compound or heterocyclic epoxy compound or other known hydrogenated epoxy resin can be used.

The alicyclic epoxy compound or the heterocyclic epoxy compound or the hydrogenated epoxy compound may be used singly or in combination of two or more. Further, in addition to the epoxy compounds, other epoxy compounds may be used in combination as long as the effects of the present invention are not impaired. For example, bisphenol A, bisphenol F, bisphenol S, tetramethyl bisphenol A, diaryl bisphenol A, hydroquinone, catechol, resorcin, cresol, Tetrabromobisphenol A, trihydroxybiphenyl, benzophenone, bis resorcinol, bisphenol hexafluoroacetone, tetramethyl bisphenol A, tetramethyl bisphenol F, tris(hydroxyphenyl)methane, Glycidyl ether obtained by reacting polyphenols such as bisphenol, phenol novolac, cresol novolak and epichlorohydrin; and glycerin, neopentyl glycol, ethylene glycol, propylene glycol, hexanediol, polyethylene a polyglycidyl ether obtained by reacting an aliphatic polyol such as an alcohol or a polypropylene glycol with epichlorohydrin; and a shrinkage obtained by reacting a hydroxycarboxylic acid such as p-hydroxybenzoic acid or β-hydroxynaphthoic acid with epichlorohydrin Glycidyl ether ester; from phthalic acid, methyl phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, endomethylene tetrahydrophthalic acid, endomethylene six a polyglycidyl ester obtained from a polycarboxylic acid such as hydrogen phthalic acid, trimellitic acid or a polymerized fatty acid; a glycidylaminoglycidyl ether obtained from an aminoalkylphenol; a glycidyl aminoglycidyl ester obtained from an aminobenzoic acid; from aniline, toluidine, tribromoaniline, xylylenediamine, Glycidylamine obtained by diaminocyclohexane, bisaminomethylcyclohexane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylanthracene or the like; ring A known epoxy resin such as an oxidized polyolefin.

Examples of the curing agent include an acid anhydride, an imidazole compound, and dicyandiamide. Among them, an acid anhydride which is hard to discolor the cured product, in particular, an alicyclic acid anhydride-based curing agent can be preferably used. specific Preferably, methylhexahydrophthalic anhydride or the like is exemplified.

In the case where an alicyclic epoxy compound and an alicyclic acid anhydride-based curing agent are used in the composition of the adhesive, if the amount of each of the alicyclic acid anhydride-based curing agents is too small, the uncured epoxy compound is changed. When the amount is too large, there is a tendency to promote corrosion of the adherend material due to the influence of the residual curing agent. Therefore, it is preferably 80 to 120 parts by mass, more preferably 100 parts by mass or more, per 100 parts by mass of the alicyclic epoxy compound. An alicyclic acid anhydride type hardener is used in a ratio of 95 to 105 parts by mass.

In the anisotropic conductive adhesive having such a configuration, when the pressure is bonded, the solder particles 32 having an average particle diameter smaller than that of the conductive particles 31 are crushed following the flat deformation of the conductive particles 31, and are caused by heating. Welding is performed for metal bonding. Therefore, the area in contact with the terminal is increased, and the heat dissipation characteristics and electrical characteristics can be improved.

<2. Connection structure and method of manufacturing the same>

Next, a connection structure using the above an anisotropic conductive adhesive will be described. The connection structure according to the present embodiment includes a first electronic component, a second electronic component, and an anisotropic conductive film. The anisotropic conductive film uses the anisotropic conductive adhesive to bond the first electronic component and the second electronic component. The anisotropic conductive adhesive comprises: conductive particles having a conductive metal layer formed on the surface of the resin particles; solder particles having an average particle diameter smaller than the conductive particles; and a binder that makes conductivity The particles and the solder particles are dispersed. The connection structure system electrically connects the terminals of the first electronic component and the terminals of the second electronic component via conductive particles, and is soldered by solder particles.

The first electronic component in the present embodiment is preferably a wafer (element) such as an LED (Light Emitting Diode) or a driver IC (Integrated Circuit) that generates heat, and the second electronic component is preferably a substrate on which a wafer is mounted.

Fig. 3 is a cross-sectional view showing a configuration example of an LED package. In the LED mounting system, the LED element and the substrate are connected by using an anisotropic conductive adhesive obtained by dispersing the conductive particles 31 and the solder particles 32 having an average particle diameter smaller than the conductive particles in the adhesive component. .

The LED element includes, on the element substrate 11 made of, for example, sapphire, a first conductive type cladding layer 12 made of, for example, n-GaN, an active layer 13 made of, for example, an In _x Al _y Ga _1-xy N layer, and The second conductive type cladding layer 14 made of, for example, p-GaN has a so-called double heterostructure. In addition, the first conductive type electrode 12a is provided in one of the first conductive type cladding layers 12, and the second conductive type electrode 14a is provided in one of the second conductive type cladding layers 14. When a voltage is applied between the first conductive type electrode 12a and the second conductive type electrode 14a of the LED element, the carrier is concentrated on the active layer 13 and recombined to emit light.

The substrate includes the first conductive type circuit pattern 22 and the second conductive type circuit pattern 23 on the substrate 21, and has electrodes at positions corresponding to the first conductive type electrode 12a and the second conductive type electrode 14a of the LED element. 22a and electrode 23a.

As shown in FIG. 3, in the LED package, the terminals (electrodes 12a and 14a) of the LED element and the terminals (electrodes 22a and 23a) of the substrate are electrically connected to each other via the conductive particles 31, and further, by using solder particles. 32 welding for metal bonding. Thereby, the contact area between the terminals is increased, and the heat generated in the active layer 13 of the LED element can be efficiently dissipated to the substrate side, and the luminous efficiency can be prevented from being lowered and the life of the LED package body can be lengthened.

Further, as shown in FIG. 4, with respect to the LED element for flip chip mounting, the terminals (electrodes 12a, 14a) of the LED element are designed to be large by the passivation material 15, and thus the conductive particles 31 and the solder particles are formed. 32 is more captured to the terminals of the LED elements (electrodes 12a, 14a) Between the terminals (circuit patterns 22, 23) of the substrate. Thereby, the heat generated by the active layer 13 of the LED element can be more efficiently dissipated to the substrate side.

Next, a method of manufacturing the above-described connection structure will be described. In the method of manufacturing the connection structure according to the embodiment, the anisotropic conductive adhesive is interposed between the terminal of the first electronic component and the terminal of the second electronic component, and the first electronic component and the second electronic component are heated. The anisotropic conductive adhesive contains: the conductive particles; the solder particles having an average particle diameter smaller than the conductive particles; and a binder that disperses the conductive particles and the solder particles. Thereby, the terminal of the first electronic component and the terminal of the second electronic component are electrically connected to each other via the conductive particles, and the terminal of the first electronic component and the terminal of the second electronic component are soldered by the solder particles. The metal-bonded connection structure.

According to the method for producing a connection structure according to the present embodiment, the conductive particles are electrically connected by flat deformation at the time of pressure bonding, and are brought into contact with the opposite terminals by soldering of the solder particles. The area is increased, so that higher heat dissipation and higher connection reliability are obtained.

[Examples]

<3. Example>

Hereinafter, the embodiments of the present invention will be described in detail, but the present invention is not limited to the embodiments. In the present embodiment, an anisotropic conductive adhesive (ACP) in which conductive particles and solder particles were blended was prepared to prepare an LED package, and heat dissipation characteristics, leakage current, and electrical characteristics were evaluated.

The production of the anisotropic conductive adhesive, the production of the LED package, the evaluation of the heat dissipation characteristics of the LED package, the evaluation of the leakage current, and the evaluation of the electrical characteristics were carried out as follows.

[Production of anisotropic conductive adhesive]

Epoxy-curing adhesive (adhesive with epoxy resin (trade name: CEL2021P, manufactured by DAICEL Chemical Co., Ltd.) and anhydride (MeHHPA, trade name: MH700, manufactured by Nippon Chemical Co., Ltd.) as a main component) The surface of the crosslinked polystyrene resin particles is coated with conductive particles having an average particle diameter (D50) of Au of 5.5 μm (trade name: AUL705, manufactured by Sekisui Chemical Co., Ltd.), and having a specific average particle diameter (D50). The solder particles are used to make an anisotropic conductive adhesive. The solder particles were prepared to have an average particle diameter (D50) of 0.8 μm, 1.1 μm, 5.0 μm, 10.0 μm, and 20.0 μm (trade name: M707, manufactured by Senju Metal Industry Co., Ltd.).

[Production of LED structure]

An LED electrode wafer (trade name: DA700, manufactured by CREE Co., Ltd., Vf = 3.2 V (If = 350 mA)) was mounted on an Au electrode substrate (ceramic substrate, conductor pitch = 100 μmP, plating) using an anisotropic conductive adhesive. Ni/plated Au = 5.0 / 0.3 μm). After the anisotropic conductive adhesive was applied onto the Au electrode substrate, it was mounted on an LED wafer, and heated and pressure-bonded under the conditions of 260 ° C - 10 seconds and a load of 1000 g / chip.

[Evaluation of heat dissipation characteristics]

The thermal resistance value (° C/W) of the LED package was measured using a transition thermal resistance measuring device (manufactured by CATS Electronic Design Co., Ltd.). The measurement conditions were carried out at If = 350 mA (constant current control).

[Evaluation of leakage current]

The LED package body was energized at -5 V/10 μA, and leakage currents having 1 μA or more were regarded as leakage and counted. The measurement was performed at n = 1000, and the yield (%) of the product was calculated.

[Evaluation of electrical characteristics]

The Vf value at the time of If=350 mA was measured as the initial Vf value. Further, the LED package was lit at If=350 mA in an environment of 85° C. and 85% RH for 500 hours (high-temperature and high-humidity test), and the Vf value at If=350 mA was measured. Furthermore, the high temperature and high humidity test is only performed on the initial good product. In the initial evaluation, it was confirmed that the short circuit between the terminals was set to "x", and the other cases were set to "○". In the evaluation after the high-temperature and high-humidity test, it is confirmed that the ON-OFF condition (OPEN) is "X", and the change from the initial Vf value to 5% or more is "△", and the value from the initial Vf value is The case where the change is less than 5% is set to "○".

Also, put it to -40 ° C / 30 min The thermal shock test at 100 ° C / 30 min, 3000 cycles, measured the Vf value at If = 350 mA. Furthermore, the thermal shock test is only performed on the initial good product. In the initial evaluation, it was confirmed that the short circuit between the terminals was set to "x", and the other cases were set to "○". In the evaluation after the thermal shock test, it is confirmed that the ON-OFF condition (OPEN) is "X", and the change from the initial Vf value to 5% or more is "△", and the change from the initial Vf value is obtained. If it is less than 5%, it is set to "○".

In Table 1, the results of evaluation of heat dissipation characteristics, leakage current, and electrical characteristics are shown in the examples and comparative examples.

<Example 1>

As shown in Table 1, the LED package using ACP in which 1% by volume of conductive particles and 2% by volume of solder particles having an average particle diameter of 5.0 μm were added to the adhesive had a thermal resistance of 21.0 ° C/W. The thermal resistance value is lower than that of Comparative Example 1, and the heat dissipation characteristics of the LED package body are successfully improved. Moreover, the number of leaks was zero, and the yield of the product was 100%. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was ○, and in the lighting test at 85 ° C in an 85% RH environment, good electrical connection reliability was also obtained after 3000 hours. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and good electrical connection reliability was also obtained after 3000 cycles of the thermal shock test.

<Example 2>

As shown in Table 1, the LED package using ACP in which 2% by volume of conductive particles and 5% by volume of solder particles having an average particle diameter of 5.0 μm were added to the adhesive had a thermal resistance value of 13.2 ° C/W. The thermal resistance value is lower than that of Comparative Example 1, and the heat dissipation characteristics of the LED package body are successfully improved. Moreover, the number of leaks was zero, and the yield of the product was 100%. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was ○, and in the lighting test at 85 ° C in an 85% RH environment, good electrical connection reliability was also obtained after 3000 hours. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and good electrical connection reliability was also obtained after 3000 cycles of the thermal shock test.

<Example 3>

As shown in Table 1, the LED package using ACP in which 2% by volume of conductive particles and 10% by volume of solder particles having an average particle diameter of 5.0 μm were added to the adhesive, the thermal resistance value was 11.8 ° C / W. The thermal resistance value is lower than that of Comparative Example 1, and the heat dissipation characteristics of the LED package body are successfully improved. Again The raw leakage is 0, and the yield of the product is 100%. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was ○, and in the lighting test at 85 ° C in an 85% RH environment, good electrical connection reliability was also obtained after 3000 hours. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and good electrical connection reliability was also obtained after 3000 cycles of the thermal shock test.

<Example 4>

As shown in Table 1, the LED package using ACP in which 15% by volume of conductive particles and 16% by volume of solder particles having an average particle diameter of 5.0 μm were added to the adhesive, the thermal resistance value was 11.0 ° C / W. The thermal resistance value is lower than that of Comparative Example 1, and the heat dissipation characteristics of the LED package body are successfully improved. Moreover, the number of leaks was zero, and the yield of the product was 100%. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was ○, and in the lighting test at 85 ° C in an 85% RH environment, good electrical connection reliability was also obtained after 3000 hours. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and good electrical connection reliability was also obtained after 3000 cycles of the thermal shock test.

<Example 5>

As shown in Table 1, the LED package using ACP in which 2% by volume of conductive particles and 25% by volume of solder particles having an average particle diameter of 5.0 μm were added to the adhesive had a thermal resistance of 10.2 ° C/W. The thermal resistance value is lower than that of Comparative Example 1, and the heat dissipation characteristics of the LED package body are successfully improved. Moreover, the number of leaks was zero, and the yield of the product was 100%. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was ○, and in the lighting test at 85 ° C in an 85% RH environment, good electrical connection reliability was also obtained after 3000 hours. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and 3,000 cycles after the thermal shock test. Good electrical connection reliability is also obtained.

<Example 6>

As shown in Table 1, the LED package using ACP in which 1% by volume of conductive particles and 30% by volume of solder particles having an average particle diameter of 5.0 μm were added to the adhesive had a thermal resistance value of 10.0 ° C/W. The thermal resistance value is lower than that of Comparative Example 1, and the heat dissipation characteristics of the LED package body are successfully improved. Moreover, the number of leaks was zero, and the yield of the product was 100%. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was ○, and in the lighting test at 85 ° C in an 85% RH environment, good electrical connection reliability was also obtained after 3000 hours. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and good electrical connection reliability was also obtained after 3000 cycles of the thermal shock test.

<Example 7>

As shown in Table 1, the LED package using ACP in which 2% by volume of conductive particles and 5% by volume of solder particles having an average particle diameter of 1.1 μm were added to the adhesive had a thermal resistance of 13.6 ° C/W. The thermal resistance value is lower than that of Comparative Example 1, and the heat dissipation characteristics of the LED package body are successfully improved. Moreover, the number of leaks was zero, and the yield of the product was 100%. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was ○, and in the lighting test at 85 ° C in an 85% RH environment, good electrical connection reliability was also obtained after 3000 hours. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and good electrical connection reliability was also obtained after 3000 cycles of the thermal shock test.

<Example 8>

As shown in Table 1, the LED package using ACP in which 20% by volume of conductive particles and 10% by volume of solder particles having an average particle diameter of 5.0 μm were added to the adhesive had a thermal resistance value of 14.5 ° C / W, the thermal resistance value is lower than that of Comparative Example 1, and the heat dissipation characteristics of the LED package body are successfully improved. Moreover, the number of leaks was zero, and the yield of the product was 100%. In addition, the evaluation result of the high-temperature and high-humidity test of electrical characteristics was ○ at the beginning and △ after the test. In the lighting test at 85 ° C in an 85% RH environment, the change from the initial Vf value was 5% or more after 3000 h. . This is considered to be because the amount of the conductive particles added is excessive, and thus the solder particles are insufficiently flattened. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and good electrical connection reliability was also obtained after 3000 cycles of the thermal shock test.

<Comparative Example 1>

As shown in Table 1, the LED package used for the ACP in which 1% by volume of the conductive particles were added to the binder and the solder particles were not added had a thermal resistance value of 40.0 ° C / W, and good heat dissipation characteristics were not obtained. Moreover, the number of leaks was zero, and the yield of the product was 100%. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was Δ, and in the lighting test at 85 ° C in an 85% RH environment, ON/OFF was generated after 3000 h. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and good electrical connection reliability was also obtained after 3000 cycles of the thermal shock test.

<Comparative Example 2>

As shown in Table 1, the LED package used for the ACP in which 40% by volume of the conductive particles were added to the adhesive and the solder particles were not added was evaluated as x in the initial stage. This is considered to be because the amount of the conductive particles added is excessive, and the anisotropy is lost.

<Comparative Example 3>

As shown in Table 1, an LED package using an ACP in which 5% by volume of a solder particle having an average particle diameter of 5.0 μm was added without adding conductive particles to a binder had a thermal resistance value of 13.2 ° C/W, and the heat was made. The resistance is lower than that of Comparative Example 1, and the heat dissipation characteristics of the LED package are successfully improved. Moreover, the number of leaks was zero, and the yield of the product was 100%. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was Δ, and in the lighting test at 85 ° C in an 85% RH environment, ON/OFF was generated after 3000 h. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, × after the test, and turned on (OPEN) after 3000 cycles of the thermal shock test. The reason is considered to be that cracks are generated in the solder joint portion due to the thermal shock test.

<Comparative Example 4>

As shown in Table 1, an LED package in which an ACP of 40% by volume of solder particles having an average particle diameter of 5.0 μm was added without adding conductive particles to the binder was evaluated as Δ. The reason is considered to be that the amount of the addition of the solder particles is excessive, so that the anisotropy is lost.

<Comparative Example 5>

As shown in Table 1, the LED package using ACP in which 2% by volume of conductive particles and 5% by volume of solder particles having an average particle diameter of 10.0 μm were added to the adhesive had a thermal resistance of 13.2 ° C/W. The thermal resistance value is lower than that of Comparative Example 1, and the heat dissipation characteristics of the LED package body are successfully improved. In addition, there were 16 leaks and the yield of the product was 98.4%. This is considered to be because the average particle diameter of the solder particles is excessively large, so that collision with the solder particles occurs at the edge portion of the wafer. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was ○, and in the lighting test at 85 ° C in an 85% RH environment, good electrical connection reliability was also obtained after 3000 hours. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and good electrical connection reliability was also obtained after 3000 cycles of the thermal shock test.

<Comparative Example 6>

As shown in Table 1, 2% by volume of conductive particles and 5% by volume were added to the binder. The LED structure of the ACP of the solder particles having an average particle diameter of 20.0 μm has a thermal resistance value of 13.2 ° C/W, which lowers the thermal resistance value compared with Comparative Example 1, and successfully improves the heat dissipation characteristics of the LED package. In addition, there were 72 leaks and the yield of the product was 92.8%. The reason for this is considered to be that, in the same manner as in Comparative Example 5, since the average particle diameter of the solder particles is excessively large, collision with the solder particles occurs at the edge portion of the wafer. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was ○, and in the lighting test at 85 ° C in an 85% RH environment, good electrical connection reliability was also obtained after 3000 hours. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and good electrical connection reliability was also obtained after 3000 cycles of the thermal shock test.

<Reference Example 1>

As shown in Table 1, the LED package using ACP in which 2% by volume of conductive particles and 5% by volume of solder particles having an average particle diameter of 0.8 μm were added to the adhesive had a thermal resistance value of 19.8 ° C/W. Get good heat dissipation characteristics. This is considered to be because the average particle diameter of the solder particles is too small, so that metal bonding is not performed between the LED wafer and the substrate wiring. Moreover, the number of leaks was zero, and the yield of the product was 100%. Further, the evaluation results of the high-temperature and high-humidity test for electrical characteristics were initially ○, and after the test was ×, and in the lighting test at 85 ° C in an 85% RH environment, ON/OFF was generated after 3000 h. Moreover, the evaluation result of the thermal shock test of electrical characteristics was ○ at the beginning, ○ after the test, and good electrical connection reliability was also obtained after 3000 cycles of the thermal shock test.

As shown in Examples 1 to 8, the heat dissipation characteristics of the LED package body were successfully improved by blending solder particles having an average particle diameter smaller than that of the conductive particles. Further, as shown in Examples 1 to 8, the average particle diameter of the solder particles is 20% or more of the average particle diameter of the conductive particles and is not reached. 100%, successfully improve the yield of products.

In addition, as shown in the first to eighth embodiments, the blending amount of the conductive particles is 1% by volume or more and 30% by volume or less, and the blending amount of the conductive particles is 1% by volume or more and 20% by volume or less. It can improve the heat dissipation characteristics and electrical characteristics of the LED structure. Further, as shown in Examples 1 to 7, by making the amount of the solder particles blended more than the conductive particles, the anisotropy was successfully improved, and the electrical characteristics were improved.

In addition, as shown in Examples 3 to 6, the blending amount of the conductive particles is 10% by volume or more and 30% by volume or less, and the blending amount of the conductive particles is 1% by volume or more and 15% by volume or less. The blending amount of the solder particles is made larger than the blending amount of the conductive particles, and excellent heat dissipation characteristics of a thermal resistance value of 12 ° C / W or less are successfully obtained.

Claims (8)

An anisotropic conductive adhesive comprising: conductive particles having a conductive metal layer formed on a surface of the resin particle and having an average particle diameter of 1 μm or more and 10 μm or less; and solder particles having an average particle diameter of the conductive particles 20% or more and less than 100% of the average particle diameter; and a binder which disperses the conductive particles and the solder particles, and the amount of the solder particles blended is 1% by volume or more and 30% by volume or less. The anisotropic conductive adhesive according to the first aspect of the invention, wherein the conductive particles are blended in an amount of 1% by volume or more and 20% by volume or less. The anisotropic conductive adhesive according to claim 2, wherein the amount of the solder particles blended is larger than the blending amount of the conductive particles. The anisotropic conductive adhesive according to the first aspect of the invention, wherein the amount of the solder particles blended is 10% by volume or more and 30% by volume or less, and the blending amount of the conductive particles is 1% by volume or more and 15 The volume of the solder particles is more than the volume of the conductive particles. The anisotropic conductive adhesive according to claim 1, wherein the solder particles are coated with an insulating layer. A connection structure comprising: a first electronic component; a second electronic component; and an anisotropic conductive film, wherein the first electronic component and the first electronic component are bonded by an anisotropic conductive adhesive The second electronic component is subsequently formed; the anisotropic conductive adhesive contains conductive particles having a conductive metal layer formed on the surface of the resin particle and having an average particle diameter of 1 μm or more and 10 μm or less; and solder particles; The average particle diameter is 20% or more and less than 100% of the average particle diameter of the conductive particles; and the binder disperses the conductive particles and the solder particles, and the amount of the solder particles is 1% by volume. In the connection structure system, the terminal of the first electronic component and the terminal of the second electronic component are electrically connected to each other via the conductive particles, and are soldered by the solder particles. The connection structure of claim 6, wherein the first electronic component is an LED component, and the second electronic component is a substrate. A method for manufacturing a connection structure, wherein an anisotropic conductive adhesive is interposed between a terminal of a first electronic component and a terminal of a second electronic component, and the first electronic component and the second electronic component are thermocompression bonded; The anisotropic conductive adhesive contains conductive particles having a conductive metal layer formed on the surface of the resin particles and having an average particle diameter of 1 μm or more and 10 μm or less. The average particle diameter of the solder particles is an average of the conductive particles. 20% or more and less than 100% of the particle diameter; and a binder that disperses the conductive particles and the solder particles, and the amount of the solder particles blended is 1% by volume or more and 30% by volume or less.