JP6609092B2 - Connection structure manufacturing method and connection structure - Google Patents

Description

  The present invention relates to a method for manufacturing a connection structure in which electrodes are electrically connected using a conductive material including conductive particles with insulating particles. The present invention also relates to a connection structure in which electrodes are electrically connected using a conductive material including conductive particles with insulating particles.

  Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In the anisotropic conductive material, conductive particles are dispersed in a binder resin.

  In order to obtain various connection structures, the anisotropic conductive material is, for example, a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)) or 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.

  For example, when the electrode of the semiconductor chip and the electrode of the glass substrate are electrically connected by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass substrate. Next, the semiconductor chips are stacked, and heated and pressurized. As a result, the anisotropic conductive material is cured, and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

  As an example of the anisotropic conductive material, the following Patent Document 1 discloses a conductive material including conductive particles with insulating particles. The conductive particles with insulating particles include resin particles and composite conductive particles having a metal layer covering the resin particles, and are provided outside the metal layer and cover a part of the surface of the metal layer. Insulating fine particles. The metal layer is a nickel-palladium alloy plating layer.

  Patent Document 1 describes that when an anisotropic conductive material is pressure-bonded, the insulating particles sink into the metal layer in the composite conductive particles.

JP 2011-29178 A

  When electrodes are electrically connected using a conventional anisotropic conductive material as described in Patent Document 1 to obtain a connection structure, the obtained connection structure may be dropped or vibrated. When a shock is applied or a temperature change such as a cooling cycle is applied, the conductive particles and the electrode are displaced, or the insulating particles are embedded in the metal layer, which becomes the starting point of the metal layer cracking. Thus, there is a problem in that the connection reliability between the electrodes is lowered due to the metal layer breaking.

  An object of the present invention is to provide a connection structure manufacturing method and connection that can improve connection reliability between electrodes in a connection structure against an impact such as dropping or vibration and a temperature change such as a thermal cycle. It is to provide a structure.

  According to a wide aspect of the present invention, conductive particles with insulating particles having conductive particles having at least a conductive portion on the surface and a plurality of insulating particles arranged on the surface of the conductive particles, and a binder resin And a first connection target member having a first electrode on the surface and a second connection target member having a second electrode on the surface, and the first electrode. Disposing the conductive material between the first connection target member and the second connection target member such that the conductive particles with insulating particles are located between the first connection target member and the second electrode. And connecting the first connection target member and the second connection target member by thermocompression bonding the first connection target member and the second connection target member. Formed of a conductive material, and the first electrode and the second electrode Electrically connecting an electrode with the conductive particles to obtain a connection structure, and the insulating particles positioned between the second electrode and the conductive particles during the thermocompression bonding Is provided in the second electrode to obtain a connection structure in which the insulating particles are embedded in the second electrode.

  Moreover, according to the wide situation of this invention, the 1st connection object member which has a 1st electrode on the surface, the 2nd connection object member which has a 2nd electrode on the surface, and the said 1st connection object member And a connection part that connects the second connection target member, and the connection part has a plurality of conductive particles having a conductive part at least on the surface, and a plurality of conductive particles arranged on the surface of the conductive particle The first electrode and the second electrode are electrically connected by the conductive particles. The conductive particles include conductive particles with insulating particles having insulating particles and a conductive material including a binder resin. A connection structure is provided in which the insulating particles are embedded in the second electrode.

  The insulating particles are preferably inorganic particles excluding metal particles. It is preferable that the insulating particles have a Vickers hardness higher than that of the second electrode. It is preferable that the Vickers hardness of the conductive part located on the surface of the conductive particles is higher than the Vickers hardness of the second electrode. The material of the surface of the second electrode that is electrically connected by the conductive particles is preferably gold.

  In a specific aspect of the manufacturing method of the connection structure according to the present invention, the insulating particles positioned between the first electrode and the conductive particles are used as the first electrode during the thermocompression bonding. A connection structure is obtained in which the insulating particles are not embedded in the first electrode without being embedded.

  In a specific aspect of the connection structure according to the present invention, the insulating particles are not embedded in the first electrode.

  It is preferable that the conductive particles have protrusions on the surface.

The terms insulating particles with conductive particles, it is preferable compression modulus when the insulating particles with conductive particles is compressed 10% at 100 ° C. is 3000N / mm ² or more, and is 10000 N / mm ² or less. With respect to the conductive particles with insulating particles, a conductive particle-containing liquid with insulating particles obtained by adding 3 parts by weight of conductive particles with insulating particles to 100 parts by weight of ethanol exceeds 20 minutes at 20 ° C. and 40 kHz. When the sonication is performed, it is preferable that the residual ratio of the insulating particles obtained by the following formula (1) is 50% or more.

  Residual rate (%) of the insulating particles = (coverage after ultrasonic treatment / coverage before ultrasonic treatment) × 100 (1)

  With respect to the conductive particles with insulating particles, the coverage, which is the area of the portion covered with the insulating particles in the entire surface area of the conductive particles, is preferably 40% or more and 80% or less.

  In the method for producing a connection structure according to the present invention, the conductive particles with insulating particles having conductive particles having at least a conductive part on the surface and a plurality of insulating particles arranged on the surface of the conductive particles, And a conductive material containing a binder resin, and a first connection target member having a first electrode on the surface and a second connection target member having a second electrode on the surface. In the method for manufacturing a connection structure according to the present invention, the first connection target member and the above-described member are arranged so that the conductive particles with insulating particles are positioned between the first electrode and the second electrode. The step of disposing the conductive material between the second connection target member and the first connection target member by thermocompression bonding the first connection target member and the second connection target member Forming a connection part connecting the second connection target member with the conductive material, and electrically connecting the first electrode and the second electrode with the conductive particles; A process for obtaining a connection structure, and in the method for manufacturing a connection structure according to the present invention, the insulating particles positioned between the second electrode and the conductive particles during the thermocompression bonding. Embedded in the second electrode, and the insulating particles are embedded in the second electrode. Since obtaining a connection structure that is embedded with respect to impact such as dropping or vibration, as well as to temperature changes, such as thermal cycling, it is possible to improve the connection reliability between the electrodes in the connection structure.

  The connection structure according to the present invention includes a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, and the above A connecting portion connecting the second connection target member, and the connecting portion further includes conductive particles having at least a conductive portion on the surface, and a plurality of the conductive particles disposed on the surface of the conductive particles. The first electrode and the second electrode are electrically connected to each other by the conductive particles. The conductive particles include conductive particles with insulating particles having insulating particles and a binder material. Are connected to each other, and the insulating particles are embedded in the second electrode, so that the electrodes in the connection structure against impacts such as dropping or vibration, and temperature changes such as cooling and cooling cycles. Can improve the connection reliability between That.

FIG. 1 is a cross-sectional view schematically showing a connection structure according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a connection portion between the first and second electrodes and the conductive particles with insulating particles in the connection structure shown in FIG. FIGS. 3A and 3B are cross-sectional views for explaining each step of the example of the method for manufacturing the connection structure shown in FIGS. FIG. 4 is a cross-sectional view showing conductive particles with insulating particles used in the connection structure shown in FIGS. FIG. 5 is a cross-sectional view showing a first modification of the conductive particles with insulating particles. FIG. 6 is a cross-sectional view showing a second modification of the conductive particles with insulating particles. FIG. 7 is a cross-sectional view showing a third modification of the conductive particles with insulating particles. FIG. 8 is a schematic diagram for explaining a method for evaluating the coverage of insulating particles and the coverage that is the area of the portion covered with the insulating particles in the entire surface area of the conductive particles.

  Details of the present invention will be described below.

  In the manufacturing method of the connection structure according to the present invention, a conductive material including conductive particles with insulating particles and a binder resin is used. The conductive particles with insulating particles include conductive particles having at least a conductive portion on the surface, and a plurality of insulating particles arranged on the surface of the conductive particles. Moreover, in the manufacturing method of the connection structure which concerns on this invention, the 1st connection object member which has a 1st electrode on the surface, and the 2nd connection object member which has a 2nd electrode on the surface are used.

  In the method for manufacturing a connection structure according to the present invention, the first connection target member and the above-described member are arranged so that the conductive particles with insulating particles are positioned between the first electrode and the second electrode. The step of disposing the conductive material between the second connection target member and the first connection target member by thermocompression bonding the first connection target member and the second connection target member Forming a connection part connecting the second connection target member with the conductive material, and electrically connecting the first electrode and the second electrode with the conductive particles; Obtaining a connection structure.

  In the manufacturing method of the connection structure according to the present invention, the insulating particles positioned between the second electrode and the conductive particles are embedded in the second electrode during the thermocompression bonding, A connection structure in which the insulating particles are embedded in the second electrode is obtained.

  Since the method for manufacturing a connection structure according to the present invention has the above-described configuration, the insulating particles are embedded in the second electrode. The reliability of the connection between the electrodes can be increased against the impact of the above and against a temperature change such as a cooling / heating cycle. For example, the connection resistance between the first and second electrodes can be kept low even when an impact such as dropping or vibration is applied to the connection structure or the connection structure is exposed to high or low temperatures. And the occurrence of poor connection can be suppressed.

  The connection structure according to the present invention includes a first connection target member having a first electrode on the surface, a second connection target member having a second electrode on the surface, the first connection target member, and the above And a connecting portion connecting the second connection target member. The connecting portion is formed using a conductive material including conductive particles with insulating particles and a binder resin. The conductive particles with insulating particles include conductive particles having at least a conductive portion on the surface, and a plurality of insulating particles arranged on the surface of the conductive particles.

  In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by the conductive particles. In the connection structure according to the present invention, the insulating particles are embedded in the second electrode.

  Since the manufacturing method of the connection structure according to the present invention has the above-described configuration, particularly the insulating particles are embedded in the second electrode. Therefore, in the connection structure, an impact such as dropping or vibration is generated. On the other hand, the connection reliability between the electrodes can be increased with respect to temperature changes such as a cooling cycle. For example, the connection resistance between the first and second electrodes can be kept low even when an impact such as dropping or vibration is applied to the connection structure or the connection structure is exposed to high or low temperatures. And the occurrence of poor connection can be suppressed.

  Hereinafter, the present invention will be clarified by describing specific embodiments and examples of the present invention with reference to the drawings.

  First, the conductive particles with insulating particles used for manufacturing the connection structure will be described.

  FIG. 4 is a cross-sectional view showing conductive particles with insulating particles used in the connection structure shown in FIGS. 1 and 2 described later.

  The conductive particles 21 with insulating particles shown in FIG. 4 include conductive particles 22 and a plurality of insulating particles 23 arranged on the surface of the conductive particles 22. Insulating particles 23 are attached to the surface of the conductive particles 22. The insulating particles 23 are made of an insulating material.

  The conductive particle 22 includes a base particle 31 and a conductive portion 32 disposed on the surface of the base particle 31. In the conductive particles 22, the conductive portion 32 is a conductive layer. The conductive part 32 covers the surface of the base particle 31. The conductive particles 22 are coated particles in which the surface of the base particle 31 is covered with the conductive portion 32. The conductive particles 22 have a conductive portion 32 on the surface. The electroconductive particle 22 should just have an electroconductive part at least on the surface. As in the case of the conductive particles 22, the base particle 31 may be different from the conductive portion 32 in the central portion. The entirety of the conductive particles may be a conductive portion.

  The conductive particles 21 with insulating particles have protrusions 21a on the conductive surface. The conductive particles 22 have protrusions 22a on the surface. The conductive portion 32 has a protrusion 32a on the surface (the outer surface of the conductive layer).

  The conductive particle 22 has a plurality of core substances 33 on the surface of the base particle 31. The conductive portion 32 covers the base particle 31 and the core substance 33. By covering the core substance 33 with the conductive portion 32, the conductive particles 22 have a plurality of protrusions 22a on the surface. The surface of the conductive portion 32 is raised by the core material 33, and a plurality of protrusions 22a are formed.

  FIG. 5 shows a first modification of the conductive particles with insulating particles.

  The conductive particles 41 with insulating particles shown in FIG. 5 include conductive particles 42 and a plurality of insulating particles 23 arranged on the surface of the conductive particles 42. The conductive particles 21 with insulating particles and the conductive particles 41 with insulating particles differ only in the presence or absence of the core substance 33.

  The conductive particles 41 with insulating particles have protrusions 41a on the conductive surface. The conductive particles 42 have protrusions 42a on the surface. The conductive portion 32A has a protrusion 32Aa on the surface (the outer surface of the conductive layer).

  The conductive particles 42 include base material particles 31 and conductive portions 32 </ b> A disposed on the surface of the base material particles 31. The conductive portion 32A is a conductive layer. The conductive particles 42 do not have a core substance like the conductive particles 22. The conductive portion 32A has a first portion and a second portion that is thicker than the first portion. Accordingly, the conductive portion 32A has a protrusion 32Aa on the surface (the outer surface of the conductive layer). A portion excluding the plurality of protrusions 42a and 32Aa is the first portion of the conductive portion 32A. The plurality of protrusions 42a and 32Aa are the second portions where the conductive portion 32A is thick.

  In order to form the protrusions 42a and 32Aa like the conductive particles 41 with insulating particles, a core substance is not necessarily used.

  FIG. 6 shows a second modification of the conductive particles with insulating particles.

  A conductive particle 51 with insulating particles shown in FIG. 6 includes conductive particles 52 and a plurality of insulating particles 23 arranged on the surface of the conductive particles 52.

  The conductive particles 52 include base material particles 31 and conductive portions 32 </ b> B disposed on the surface of the base material particles 31. The conductive part 32B is a conductive layer. The conductive portion 32B has a first conductive portion 32Bx disposed on the surface of the base particle 31 and a second conductive portion 32By disposed on the surface of the first conductive portion 32Bx.

  The conductive particles 51 with insulating particles have protrusions 51a on the conductive surface. The conductive particles 52 have protrusions 52a on the surface. The conductive portion 32B has a protrusion 32Ba on the surface (the outer surface of the conductive layer).

  The conductive particles 52 have a plurality of core materials 33 on the surface of the first conductive portion 32Bx. The second conductive portion 32By covers the first conductive portion 32Bx and the core substance 33. The substrate particles 31 and the core substance 33 are arranged with a space therebetween. A first conductive portion 32Bx exists between the base particle 31 and the core substance 33. By covering the core material 33 with the second conductive portion 32By, the conductive particles 52 have a plurality of protrusions 52a on the surface of the conductive portion 32B. The surfaces of the conductive portion 32B and the second conductive portion 32By are raised by the core material 33, and a plurality of protrusions 32Ba are formed.

  Like the conductive particles 51 with insulating particles, the conductive portion 32B may have a multilayer structure. Further, in order to form the protrusions 52a and 32Ba, the core material 33 is disposed on the first conductive portion 32Bx of the inner layer, and the core material 33 and the first conductive portion 32Bx are separated by the second conductive portion 32By of the outer layer. It may be coated.

  FIG. 7 shows a third modification of the conductive particles with insulating particles.

  The conductive particles 61 with insulating particles shown in FIG. 7 include conductive particles 62 and a plurality of insulating particles 23 arranged on the surface of the conductive particles 62.

  The conductive particles 62 include base material particles 31 and conductive portions 32 </ b> C arranged on the surface of the base material particles 31. The conductive portion 32C is a conductive layer. The conductive particles 62 do not have a core material.

  The conductive particles 61 with insulating particles do not have protrusions on the conductive surface. The conductive particles 62 do not have protrusions on the surface. Thus, the conductive particles with insulating particles may not have protrusions on the conductive surface. The conductive particles may not have protrusions on the surface. However, from the viewpoint of more easily embedding the insulating particles in the second electrode, and from the viewpoint of effectively eliminating the conductive particles and the oxide film on the surface of the electrode to further improve the conduction reliability, The conductive particles preferably have protrusions on the surface.

  The connection structure according to the present invention is manufactured using the conductive particles with insulating particles 21, 41, 51, 61 and the like as described above. However, if the conductive particles with insulating particles having conductive particles having at least a conductive portion on the surface and a plurality of insulating particles arranged on the surface of the conductive particles, the conductive with insulating particles Conductive particles with insulating particles other than the particles 21, 41, 51, 61 may be used.

  Next, a connection structure according to an embodiment of the present invention will be specifically described with reference to FIGS.

  FIG. 1 is a cross-sectional view schematically showing a connection structure according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a connection portion between the first and second electrodes and the conductive particles with insulating particles in the connection structure shown in FIG.

  The connection structure 1 shown in FIGS. 1 and 2 connects the first connection target member 2, the second connection target member 3, the first connection target member 2, and the second connection target member 3. A connecting portion 4. The connection portion 4 is formed using a conductive material including the conductive particles 21 with insulating particles and the binder resin 11. Instead of the conductive particles 21 with insulating particles, other conductive particles with insulating particles such as the conductive particles 41, 51, 61 with insulating particles may be used.

  As shown in FIG. 2, in the connection structure 1, the insulating particles 23 are embedded in the second electrode 3a. Since the insulating particles 23 are embedded in the second electrode 3a, the first and second components in the connection structure 1 are resistant to impacts such as dropping or vibration, and to temperature changes such as a thermal cycle. The connection reliability between the electrodes 2a and 3a can be improved.

  As shown in FIG. 2, in the connection structure 1, the insulating particles 23 are not embedded in the first electrode 2a.

  Specifically, the connection structure 1 shown in FIG. 1 can be obtained as follows, for example, through the states shown in FIGS. 3 (a) and 3 (b).

  As shown in FIG. 3A, the first connection target member 2 having the first electrode 2a on the surface (upper surface) is prepared. In addition, a conductive material including a plurality of conductive particles 21 with insulating particles and a binder resin 11 is prepared. Next, the conductive material layer 4 </ b> A is disposed on the surface of the first connection target member 2 on the first electrode 2 a side using the conductive material. At this time, it is preferable that one or a plurality of conductive particles 21 with insulating particles are disposed on the first electrode 2a. Here, since the conductive paste is used as the conductive material, the conductive paste is arranged by applying the conductive paste.

  Next, as shown in FIG.3 (b), the 2nd connection object member 3 which has the 2nd electrode 3a on the surface on the surface opposite to the 1st connection object member 2 side of 4 A of electrically-conductive material layers. Are arranged from the second electrode 3a side. That is, the conductive material layer 4 </ b> A is disposed between the first connection target member 2 and the second connection target member 3. Moreover, the 2nd connection object member 3 is arrange | positioned so that the 1st electrode 2a and the 2nd electrode 3a may oppose. At this time, the conductive material is arranged so that the conductive particles 21 with insulating particles are located between the first electrode 2a and the second electrode 3a.

  When or after the second connection target member 3 is arranged, the first connection target member 2 and the second connection target member 3 are thermocompression bonded. Thereby, the connection part 4 which connects the 1st connection object member 2 and the 2nd connection object member 3 is formed by 4 A of electrically-conductive material layers. In the present embodiment, the insulating particles 23 in the conductive particles 21 with insulating particles are embedded in the second electrode 3a. In the present embodiment, the insulating particles 23 are not embedded in the first electrode 2a, but the insulating particles 23 may also be embedded in the first electrode 2a.

  Further, by bringing the first electrode 2a and the second electrode 3a into contact with the conductive particles 22 and the conductive portion 32 in the conductive particles 21 with insulating particles, the first electrode 2a and the second electrode 3a Can be electrically connected.

  During the thermocompression bonding, the conductive material layer 4A is heated and pressurized. In addition, when the said binder resin has thermosetting property, it will be in the state which the said binder resin hardened | cured in the said connection part. The binder resin preferably has thermosetting properties, and it is preferable that the conductive material layer is cured by heating the conductive material layer to form the connection portion. It is preferable that the connection part 4 contains the hardened binder resin. In addition, the contact area between the first and second electrodes and the conductive particles is reduced by compressing the conductive particles with insulating particles between the first electrode and the second electrode by pressurization. Can be bigger. For this reason, conduction reliability can be improved.

  When the binder resin has thermosetting properties, the heating temperature for curing the conductive material layer is preferably 100 ° C. or higher, more preferably 120 ° C. or higher, still more preferably 140 ° C. or higher, and particularly preferably 160 ° C. As mentioned above, Preferably it is 250 degrees C or less, More preferably, it is 200 degrees C or less.

The pressure applied during the thermocompression bonding is preferably 9.8 × 10 ⁴ or more, and preferably 4.9 × 10 ⁶ Pa or less.

  As described above, the connection structure 1 shown in FIG. 1 can be obtained.

  In the conductive particles with insulating particles, it is preferable that the conductive particles and the insulating particles are firmly attached. Since the conductive particles and the insulating particles are firmly attached, the insulating particles are more easily embedded in the second electrode.

  Regarding the conductive particles with insulating particles, a conductive particle-containing liquid with insulating particles obtained by adding 3 parts by weight of conductive particles with insulating particles to 100 parts by weight of ethanol for 5 minutes under the conditions of 20 ° C. and 40 kHz. When the ultrasonic treatment is performed, it is preferable that the remaining ratio of the insulating particles obtained by the formula (1) described later is 50% or more. The residual ratio of the insulating particles is more preferably 60% or more, further preferably more than 70%, particularly preferably 80% or more, and most preferably 90% or more. When the residual ratio of the insulating particles is equal to or higher than the lower limit, the insulating particles are more easily embedded in the second electrode.

  The coverage, which is the area of the portion covered with the insulating particles in the entire surface area of the conductive particles, is preferably 40% or more, and more preferably 50% or more. When the coverage is equal to or higher than the lower limit, the insulating particles are more easily embedded in the second electrode. Furthermore, adjacent conductive particles are more difficult to contact. The coverage is preferably 80% or less, more preferably 70% or less. When the coverage is not more than the above upper limit, the contact area between the conductive particles and the second electrode is further increased.

  The remaining rate of the insulating particles and the coverage, which is the area of the portion covered with the insulating particles in the entire surface area of the conductive particles, are obtained as follows.

  Before the ultrasonic treatment described below, 100 conductive particles with insulating particles were observed by observation with a scanning electron microscope (SEM), and the coverage X1 (% of conductive particles in the conductive particles with insulating particles) ) (Also referred to as adhesion rate X1 (%)). The said coverage is an area (projection area) of the part coat | covered with the insulating particle which occupies for the whole surface area of electroconductive particle.

  Specifically, as shown in FIG. 8, when the conductive particles A with insulating particles are observed from one direction with a scanning electron microscope (SEM), the coverage is as follows. One insulating particle B1 present in a circle on the outer surface (outer peripheral edge) of the conductive part, insulating property present on the circumference of the outer surface (outer peripheral edge) of the conductive part of the conductive particle A with insulating particles The number of particles B2 is counted as 0.5, and is represented by the ratio of the projected area of the insulating particles to the projected area of the conductive particles A with insulating particles. That is, the said coverage is represented by following formula (2).

  Coverage (%) = (((number of insulating particles in circle) × 1 + (number of insulating particles on the circumference) × 0.5) × projection area of insulating particles) / (with insulating particles) Projected area of conductive particles) × 100 (2)

  Next, 3 parts by weight of the conductive particles with insulating particles are added to 100 parts by weight of ethanol to obtain a conductive particle-containing liquid with insulating particles. This conductive particle-containing liquid with insulating particles is subjected to ultrasonic treatment while being stirred for 5 minutes at 20 ° C. and 38 kHz or 40 kHz with a 400 W ultrasonic cleaner. After the ultrasonic treatment, 100 conductive particles with insulating particles are observed by observation with an SEM, and the portion of the conductive particles with insulating particles covered by the insulating particles occupying the entire surface area of the conductive particles. A coverage ratio X2 (%) (also referred to as an adhesion ratio X2 (%)), which is a projected area, is obtained. The residual rate of the insulating particles is a value represented by the following formula (1) from the coverage X1 and the coverage X2.

  Residual rate of insulating particles (%) = (coverage ratio X2 after ultrasonic treatment / coverage ratio X1 before ultrasonic treatment) × 100 Formula (1)

  From the viewpoint of further enhancing the conduction reliability and the insulation reliability between the electrodes, the CV value (coefficient of variation) of the particle diameter of the conductive particles with insulating particles is preferably 8% or less, more preferably 5% or less. It is. The CV value of the particle diameter of the conductive particles with insulating particles is calculated by the following formula.

  CV value (%) of particle diameter of conductive particles with insulating particles = standard deviation of particle diameter of conductive particles with insulating particles / average particle diameter of conductive particles with insulating particles × 100

Compression modulus when the insulating particles with conductive particles is compressed 10% at 100 ° C. with respect to (10% K value) is preferably 3000N / mm ² or more, more preferably 5000N / mm ² or more, preferably 10000N / Mm ² or less, more preferably 8000 N / mm ² or less. When the 10% K value is equal to or more than the lower limit, the insulating particles are more easily embedded in the second electrode. When the 10% K value is less than or equal to the above upper limit, the contact area between the conductive particles and the first and second electrodes is further increased, and the conduction reliability is further increased. The temperature at which the 10% K value is measured is set to 100 ° C., in many cases, the 10% compression state in the actual crimping process is achieved near 100 ° C., and the 10% compression state is 100 ° C. This is because it is desirable to achieve the temperature around 0 ° C. When the 10% K value at 100 ° C. of the conductive particles is within the above range, the versatility of the conductive material is excellent.

  The compression elastic modulus (10% K value) at 100 ° C. is measured as follows.

  With the stage on which the particles of the micro-compression tester are placed maintained at 100 ° C., with a smooth indenter end face of a cylinder (diameter 50 μm, made of diamond) under conditions of a compression speed of 0.33 mN / sec and a maximum test load of 20 mN The conductive particles with insulating particles are compressed. The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the compression elastic modulus can be obtained by the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used.

10% K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value (N) when conductive particles with insulating particles are compressively deformed by 10%
S: Compression displacement (mm) when conductive particles with insulating particles are 10% compressively deformed
R: radius of conductive particles with insulating particles (mm)

  The compression elastic modulus universally and quantitatively represents the hardness of the conductive particles with insulating particles. By using the compression modulus, the hardness of the conductive particles with insulating particles can be expressed quantitatively and uniquely.

  From the viewpoint of more easily embedding the insulating particles in the second electrode, it is preferable that the Vickers hardness of the insulating particles is higher than the Vickers hardness of the second electrode. The absolute value of the difference between the Vickers hardness of the insulating particles and the Vickers hardness of the second electrode is preferably 700 or more, more preferably 900 or more. The upper limit of the absolute value of the difference between the Vickers hardness of the insulating particles and the Vickers hardness of the second electrode is not particularly limited. The absolute value of the difference between the Vickers hardness of the insulating particles and the Vickers hardness of the second electrode is, for example, 3000 or less.

  From the viewpoint of more easily embedding the insulating particles in the second electrode, it is preferable that the Vickers hardness of the conductive portion located on the surface of the conductive particles is higher than the Vickers hardness of the second electrode. . The absolute value of the difference between the Vickers hardness of the conductive part located on the surface of the conductive particles and the Vickers hardness of the second electrode is preferably 300 or more, more preferably 400 or more. The upper limit of the absolute value of the difference between the Vickers hardness of the conductive part located on the surface of the conductive particles and the Vickers hardness of the second electrode is not particularly limited. The absolute value of the difference between the Vickers hardness of the conductive part located on the surface of the conductive particles and the Vickers hardness of the second electrode is, for example, 1000 or less.

  From the viewpoint of further improving the connection reliability between the electrodes against impacts such as dropping or vibration and temperature changes such as a cooling / heating cycle, the above-mentioned second per conductive particle with insulating particles The number of the insulating particles embedded in the electrode is preferably 1 or more, more preferably 3 or more. The upper limit of the number of the insulating particles embedded in the second electrode per one conductive particle with insulating particles is not particularly limited. From the viewpoint of further enhancing the conduction reliability between the electrodes, the number of the insulating particles embedded in the second electrode per conductive particle with one insulating particle is, for example, 10 or less.

  Hereinafter, other details of the conductive particles with insulating particles, the conductive material, and the connection structure will be described.

(Other details of conductive particles with insulating particles)
Examples of the substrate particles include resin particles, inorganic particles excluding metal particles, organic-inorganic hybrid particles, and metal particles. The substrate particles are preferably substrate particles excluding metal particles, and more preferably resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles.

  The substrate particles are preferably resin particles formed of a resin. When connecting the electrodes, the conductive particles are generally compressed after the conductive particles are arranged between the electrodes. When the substrate particles are resin particles, the conductive particles are easily deformed by compression, and the contact area between the conductive particles and the electrode is increased. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  Various organic materials are suitably used as the material for the resin particles. Examples of the resin particle material include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polyalkylene terephthalate, polysulfone. , Polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polysulfone, polyphenylene oxide, Polyacetal, polyimide, polyamideimide, polyether ether Ketones, polyether sulfones, and polymers such as obtained by a variety of polymerizable monomer having an ethylenically unsaturated group is polymerized with one or more thereof. In addition, by polymerizing one or more of various polymerizable monomers having an ethylenically unsaturated group, it is possible to design and synthesize resin particles having any compression property suitable for conductive materials. . Further, since the hardness of the base particles can be easily controlled within a suitable range, the material of the resin particles is a polymer obtained by polymerizing one or more polymerizable monomers having a plurality of ethylenically unsaturated groups. It is preferable that

  When the resin particles are obtained by polymerizing a monomer having an ethylenically unsaturated group, the monomer having the ethylenically unsaturated group may be a non-crosslinkable monomer or a crosslinkable monomer. And a polymer.

  Examples of the non-crosslinkable monomer include styrene monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl ( Alkyl (meth) acrylates such as meth) acrylate and isobornyl (meth) acrylate; oxygen such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate (Meth) acrylates; nitrile-containing monomers such as (meth) acrylonitrile; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether; vinyl acids such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate Esters; Unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; Halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride and chlorostyrene Is mentioned.

  Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipenta Erythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylates such as acrylate, (poly) tetramethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate; triallyl (iso) cyanure And silane-containing monomers such as triallyl trimellitate, divinylbenzene, diallyl phthalate, diallylacrylamide, diallyl ether, γ- (meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, vinyltrimethoxysilane It is done.

  The resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of polymerization by swelling a monomer together with a radical polymerization initiator using non-crosslinked seed particles.

  In the case where the substrate particles are inorganic particles or organic-inorganic hybrid particles excluding metal particles, examples of the inorganic material that is a material of the substrate particles include silica and carbon black. The particles formed from the silica are not particularly limited. For example, after forming a crosslinked polymer particle by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups, firing may be performed as necessary. The particle | grains obtained by performing are mentioned. Examples of the organic / inorganic hybrid particles include organic / inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

  When the substrate particles are metal particles, examples of the metal that is a material of the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, the substrate particles are preferably not metal particles.

  The average particle diameter of the substrate particles is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, still more preferably 1.5 μm or more, particularly preferably 2 μm or more, preferably 1000 μm or less. More preferably, it is 500 μm or less, more preferably 300 μm or less, still more preferably 100 μm or less, still more preferably 50 μm or less, still more preferably 30 μm or less, particularly preferably 5 μm or less, and most preferably 3 μm or less. When the average particle diameter of the base particles is equal to or more than the above lower limit, the contact area between the conductive particles and the electrodes is increased, so that the conduction reliability between the electrodes is further increased and the conductive particles are connected via the conductive particles. The connection resistance between the electrodes is further reduced. Further, when the conductive portion is formed on the surface of the base particle by electroless plating, it becomes difficult to aggregate and the aggregated conductive particles are hardly formed. When the average particle diameter of the substrate particles is not more than the above upper limit, the conductive particles are easily compressed, the connection resistance between the electrodes is further reduced, and the interval between the electrodes is further narrowed.

  The average particle diameter of the substrate particles is particularly preferably 0.1 μm or more and 5 μm or less. When the average particle diameter of the substrate particles is in the range of 0.1 to 5 μm, even when the distance between the electrodes is small and the thickness of the conductive part is increased, small conductive particles can be obtained. From the viewpoint of obtaining even smaller conductive particles even if the distance between the electrodes is further reduced or the thickness of the conductive portion is increased, the average particle diameter of the base particles is preferably 0.5 μm. Above, more preferably 2 μm or more, preferably 3 μm or less.

  The average particle diameter is a number average particle diameter. The average particle diameter can be measured using, for example, a Coulter counter (manufactured by Beckman Coulter).

  The thickness of the conductive portion (when there are a plurality of conductive portions, the total thickness of the plurality of conductive portions) is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more, particularly preferably 50 nm or more, preferably Is 1000 nm or less, more preferably 800 nm or less, still more preferably 500 nm or less, particularly preferably 400 nm or less, and most preferably 300 nm or less. When the thickness of the conductive part is equal to or greater than the lower limit, the conductivity of the conductive particles is further improved. When the thickness of the conductive part is not more than the above upper limit, the difference in coefficient of thermal expansion between the base particle and the metal layer becomes small, and the metal layer becomes difficult to peel from the base particle.

  Examples of a method for forming the conductive part on the surface of the substrate particle include a method for forming the conductive part by electroless plating and a method for forming the conductive part by electroplating.

  The conductive part preferably contains a metal. The metal that is the material of the conductive part is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, molybdenum, tungsten and cadmium, and alloys thereof. Is mentioned. Further, tin-doped indium oxide (ITO) may be used as the metal. As for the said metal, only 1 type may be used and 2 or more types may be used together.

  The conductive particles with insulating particles preferably have protrusions on the conductive surface, and the conductive particles preferably have protrusions on the surface. It is preferable that there are a plurality of protrusions. Since the core substance is embedded in the conductive portion, protrusions can be easily formed on the outer surface of the conductive portion. An oxide film is often formed on the surface of the electrode connected by the conductive particles. When conductive particles with insulating particles having conductive protrusions are used, the oxide film is effectively eliminated by the protrusions by placing conductive particles with insulating particles between the electrodes and pressing them. The For this reason, an electrode and electroconductive particle contact more reliably and the connection resistance between electrodes becomes still lower. Furthermore, the protrusion effectively eliminates the binder resin between the conductive particles and the electrode. For this reason, the conduction | electrical_connection reliability between electrodes becomes high.

  As a method for forming protrusions on the surface of the conductive particles, a method of forming a conductive portion by electroless plating after attaching a core substance to the surface of the base particles, and electroless plating on the surface of the base particles Examples include a method of forming a conductive part by, attaching a core substance, and further forming a conductive part by electroless plating. As another method for forming the protrusion, a first conductive part is formed on the surface of the base particle, and then a core substance is disposed on the first conductive part, and then the second conductive part. And a method of adding a core substance in the middle of forming a conductive part on the surface of the base particle.

  As a method of attaching the core substance to the surface of the base particle, for example, a core substance is added to the dispersion of the base particle, and the core substance is applied to the surface of the base particle by, for example, van der Waals force. Examples thereof include a method of accumulating and adhering, and a method of adding a core substance to a container containing base particles and attaching the core substance to the surface of the base particles by a mechanical action such as rotation of the container. Especially, since the quantity of the core substance to adhere is easy to control, the method of making a core substance accumulate and adhere on the surface of the base particle in a dispersion liquid is preferable.

  Examples of the material constituting the core material include conductive materials and non-conductive materials. Examples of the conductive material include conductive non-metals such as metals, metal oxides, and graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Examples of the nonconductive material include silica, alumina, and zirconia. Among them, metal is preferable because conductivity can be increased and connection resistance can be effectively reduced. The core substance is preferably metal particles.

  Examples of the metal include gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium, molybdenum, tungsten, and cadmium. And alloys composed of two or more kinds of metals such as a tin-lead alloy, a tin-copper alloy, a tin-silver alloy, a tin-lead-silver alloy, and tungsten carbide. Of these, nickel, copper, silver or gold is preferable. The metal that is the material of the core substance may be the same as or different from the metal that is the material of the conductive part. It is preferable that the metal which comprises the said core substance contains nickel. Examples of the metal oxide include alumina, silica and zirconia.

  The shape of the core material is not particularly limited. The shape of the core substance is preferably a lump. Examples of the core substance include a particulate lump, an agglomerate in which a plurality of fine particles are aggregated, and an irregular lump.

  The average diameter (average particle diameter) of the core substance is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, more preferably 0.2 μm or less. When the average diameter of the core substance is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is effectively reduced.

  The “average diameter (average particle diameter)” of the core substance indicates a number average diameter (number average particle diameter). The average diameter of the core material is obtained by observing 50 arbitrary core materials with an electron microscope or an optical microscope and calculating an average value.

  The average height of the protrusions in the conductive particles is preferably 0.001 μm or more, more preferably 0.05 μm or more, still more preferably more than 0.1 μm, particularly preferably 0.125 μm or more, preferably 0.9 μm. Below, it is more preferably 0.3 μm or less, still more preferably 0.2 μm or less. When the average height of the protrusions is not less than the above lower limit and not more than the above upper limit, the connection resistance between the electrodes is effectively reduced. In particular, when the average height of the protrusions in the conductive particles is 0.125 μm or more, the arrangement accuracy of the conductive particles and the connection reliability between the electrodes are further improved. In particular, when the average height of the protrusions in the conductive particles is 0.3 μm or less, the arrangement accuracy of the conductive particles and the connection reliability between the electrodes are further improved.

  The conductive particles with insulating particles have insulating particles. For this reason, when electroconductive particle is used for the connection between electrodes, it will become difficult to produce the short circuit between adjacent electrodes. Specifically, when a plurality of conductive particles are in contact with each other, insulating particles are present between the plurality of electrodes, so that it is difficult to cause a short circuit between electrodes adjacent in the lateral direction instead of between the upper and lower electrodes.

  Examples of the material for the insulating particles include polyolefins, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, thermoplastic resins, crosslinked thermoplastic resins, thermosetting resins, water-soluble resins, and the like. Is mentioned.

  Examples of the polyolefins include polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid ester copolymer. Examples of the (meth) acrylate polymer include polymethyl (meth) acrylate, polyethyl (meth) acrylate, and polybutyl (meth) acrylate. Examples of the block polymer include polystyrene, styrene-acrylic acid ester copolymer, SB type styrene-butadiene block copolymer, SBS type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymers and vinyl copolymers. As said thermosetting resin, an epoxy resin, a phenol resin, a melamine resin, etc. are mentioned. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, and methyl cellulose.

  The insulating particles may be resin particles obtained by (co) polymerizing one or more monomers having an unsaturated double bond. Examples of the monomer having an unsaturated double bond include (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth). Acrylate, glycidyl (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerol tri (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (Meth) acrylates such as (meth) acrylate and 1,4-butanediol di (meth) acrylate; vinyl ethers; vinyl chloride; styrene compounds such as styrene and divinyl benzene, acrylonitrile, and the like. That. Of these, (meth) acrylic acid esters are preferably used.

  Furthermore, examples of the material for the insulating particles include inorganic compounds excluding metals. Examples of the inorganic compound include silica, alumina and zirconia. From the viewpoint of more easily embedding the insulating particles in the second electrode, the material of the insulating particles is preferably silica.

  From the viewpoint of more easily embedding the insulating particles in the second electrode, the insulating particles are preferably inorganic particles excluding metal particles. Of these, the insulating particles are preferably silica particles.

  Furthermore, examples of the material for the insulating particles include hybrid particles of an inorganic compound and an organic compound, particles obtained by coating an inorganic compound with an organic compound, and particles obtained by coating an organic substance with an inorganic substance. Among these, the insulating particles are preferably particles in which an organic compound is coated on silica particles. The organic compound is preferably an organic polymer.

  Examples of the method for attaching insulating particles to the surface of the conductive part include a chemical method and a physical or mechanical method. Examples of the chemical method include a method in which insulating particles are attached on the conductive portion by a hetero-aggregation method using van der Waals force or electrostatic force, and further chemically bonded as necessary. Examples of the physical or mechanical method include spray drying, hybridization, electrostatic adhesion, spraying, dipping, and vacuum deposition. Especially, since the said insulating particle cannot separate | separate easily, the method of making the said insulating particle adhere to the surface of the said electroconductive part through a chemical bond is preferable.

  The surface of the conductive part and the surface of the insulating particles may each be coated with a compound having a reactive functional group. The surface of the conductive part and the surface of the insulating particles may not be directly chemically bonded, but may be indirectly chemically bonded by a compound having a reactive functional group. After introducing a carboxyl group into the surface of the conductive part, the carboxyl group may be chemically bonded to a functional group on the surface of the insulating particle through a polymer electrolyte such as polyethyleneimine.

  The average particle size of the insulating particles is preferably 1/5 or less of the particle size of the conductive particles. In this case, the average particle diameter of the insulating particles is not too large, and the electrical connection by the conductive particles is more reliably achieved. When the average particle diameter of the insulating particles is 1/5 or less of the particle diameter of the conductive particles, when the insulating particles are adhered by the heteroaggregation method, the surface of the conductive particles is Insulating particles can be adsorbed efficiently. From the viewpoint of more easily embedding the insulating particles in the second electrode and further improving the connection reliability against impact and thermal shock, the average particle size of the insulating particles is the same as the particle size of the conductive particles. Preferably it is 1/5 or less, more preferably 1/8 or less. From the viewpoint of more easily embedding the insulating particles in the second electrode and further improving the connection reliability against impact and thermal shock, the average particle size of the insulating particles is the same as the particle size of the conductive particles. Preferably it is 1/100 or more, more preferably 1/30 or more. The average particle diameter of the insulating particles is preferably 5 nm or more, more preferably 10 nm or more, preferably 1000 nm or less, more preferably 500 nm or less. When the average particle diameter of the insulating particles is equal to or more than the lower limit, the insulating particles can be more easily embedded in the second electrode. Furthermore, the distance between adjacent conductive particles becomes larger than the hopping distance of electrons, so that leakage hardly occurs. When the average particle diameter of the insulating particles is not more than the above upper limit, the pressure and the amount of heat required for thermocompression bonding are reduced. From the viewpoint of more easily embedding the insulating particles in the second electrode and further improving the connection reliability against impact and thermal shock, the average particle diameter of the insulating particles is most preferably 400 nm or less. From the viewpoint of more easily embedding the insulating particles in the second electrode and further improving the connection reliability against impact and thermal shock, the average particle diameter of the insulating particles is particularly preferably 100 nm or more, most preferably. Is 175 nm or more. From the viewpoint of further improving the connection reliability against thermal shock, the average particle diameter of the insulating particles is most preferably 190 nm or more.

  The “average particle diameter” of the insulating particles indicates a number average particle diameter. The average particle size of the insulating particles is determined using a particle size distribution measuring device or the like.

  The CV value of the particle diameter of the insulating particles is preferably 20% or less. When the CV value is 20% or less, the thickness of the covering portion of the insulating particles becomes uniform, and it becomes easy to apply a uniform pressure when thermocompression bonding between electrodes, and poor conduction is less likely to occur. In addition, the CV value of the particle diameter of the insulating particles is calculated by the following formula.

  CV value (%) of particle diameter of insulating particles = standard deviation of particle diameter of insulating particles / average particle diameter of insulating particles × 100

  The particle size distribution can be measured with a particle size distribution meter or the like before the insulating particles are arranged on the surface of the conductive particles. The particle size distribution can be measured by image analysis of an SEM photograph after the insulating particles are arranged on the surface of the conductive particles.

  The insulating particles preferably have a polar functional group in order to adhere to the surface of the conductive particles by heteroaggregation. Examples of the polar functional group include an ammonium group, a sulfonium group, a phosphate group, and a hydroxysilyl group. The polar functional group can be introduced by copolymerizing a monomer having the polar functional group and an unsaturated double bond.

  Examples of the monomer having an ammonium group include N, N-dimethylaminoethyl methacrylate, N, N-dimethylaminopropylacrylamide, and N, N, N-trimethyl-N-2-methacryloyloxyethylammonium chloride. It is done. Examples of the monomer having a sulfonium group include phenyldimethylsulfonium methylsulfate methacrylate. Examples of the monomer having a phosphoric acid group include acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, acid phosphooxypolyoxyethylene glycol monomethacrylate, and acid phosphooxypolyoxypropylene glycol monomethacrylate. Examples of the monomer having a hydroxysilyl group include vinyltrihydroxysilane and 3-methacryloxypropyltrihydroxysilane.

  As another method for introducing a polar functional group onto the surface of the insulating particle, there is a method using a radical initiator having a polar group as an initiator when the monomer having an unsaturated double bond is polymerized. Can be mentioned. Examples of the radical initiator include 2,2′-azobis {2-methyl-N- [2- (1-hydroxy-butyl)]-propionamide}, 2,2′-azobis [2- (2- Imidazolin-2-yl) propane], 2,2′-azobis (2-amidinopropane) and salts thereof.

(Conductive material)
The conductive material includes the conductive particles with insulating particles described above and a binder resin. The conductive material is preferably an anisotropic conductive material. The anisotropic conductive material includes a conductive material for conducting between the upper and lower electrodes. The conductive material is preferably used for electrical connection between electrodes. The conductive material is preferably a conductive material for circuit connection.

  The binder resin is not particularly limited. In general, an insulating resin is used as the binder resin. Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. As for the said binder resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the vinyl resin include vinyl acetate resin, acrylic resin, and styrene resin. Examples of the thermoplastic resin include polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. Examples of the curable resin include an epoxy resin, a urethane resin, a polyimide resin, and an unsaturated polyester resin. The curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. The curable resin may be used in combination with a curing agent. Examples of the thermoplastic block copolymer include a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a hydrogenated product of a styrene-butadiene-styrene block copolymer, and a styrene-isoprene. -Hydrogenated product of a styrene block copolymer. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

  In addition to the conductive particles with insulating particles and the binder resin, the conductive material includes, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, and heat stability. Various additives such as an agent, a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant may be contained.

  The method for dispersing the conductive particles with insulating particles in the binder resin is not particularly limited, and a conventionally known dispersion method can be used. As a method for dispersing the conductive particles with insulating particles in the binder resin, for example, the conductive particles with insulating particles are added to the binder resin and then kneaded and dispersed with a planetary mixer or the like. A method, a method in which the conductive particles with insulating particles are uniformly dispersed in water or an organic solvent using a homogenizer or the like, then added to the binder resin, and kneaded and dispersed with a planetary mixer or the like; and Examples include a method of diluting the binder resin with water or an organic solvent, adding the conductive particles with insulating particles, and kneading and dispersing with a planetary mixer or the like.

  The conductive material can be used as a conductive paste and a conductive film. When the conductive material is a conductive film, a film that does not include conductive particles with insulating particles may be laminated on a conductive film that includes conductive particles with insulating particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

  The conductive material is preferably a conductive paste from the viewpoint of suppressing generation of voids in the connection portion of the connection structure and further improving the conduction reliability. The conductive material is preferably a conductive paste and is applied to the upper surface of the connection target member in a paste state.

  The content of the binder resin in 100% by weight of the conductive material is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, preferably 99.99% by weight or less, more preferably 90.99% by weight or less. When the content of the binder resin is not less than the above lower limit and not more than the upper limit, the conductive particles are efficiently arranged between the electrodes, and the conduction reliability between the electrodes is further enhanced.

  In 100% by weight of the conductive material, the content of the conductive particles with insulating particles is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, preferably 80% by weight or less, more preferably 40%. % By weight or less, more preferably 20% by weight or less, particularly preferably 10% by weight or less. When the content of the conductive particles with insulating particles is not less than the above lower limit and not more than the upper limit, the conduction reliability between the electrodes is further enhanced.

(Other details of connection structure)
Specific examples of the connection target member include electronic components such as semiconductor chips, capacitors, and diodes, and electronic components that are circuit boards such as printed boards, flexible printed boards, glass epoxy boards, and glass boards. The connection target member is preferably an electronic component.

  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 silver electrode, a molybdenum 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, 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, 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.

  From the viewpoint of more easily embedding the insulating particles in the second electrode, it is preferable that the material of the surface electrically connected by the conductive particles of the second electrode is tin or gold, More preferably, it is gold. When the material of the surface electrically connected by the conductive particles of the second electrode is gold, the effect of the present invention is remarkably obtained.

  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.

Example 1
(1) Conductive particles with insulating particles The surface of divinylbenzene resin particles (average particle diameter 3 μm) is covered with a nickel plating layer (thickness 0.1 μm), and a plurality of protrusions (average on the surface of the nickel plating layer) Conductive particles with insulating particles having conductive particles having a height of 150 nm) and a plurality of silica particles (average particle diameter of 200 nm) adhering to the surface of the conductive particles were prepared.

  Regarding the conductive particles, the nickel plating layer had a Vickers hardness of 630, and the silica particles had a Vickers hardness of 1020. Regarding the Vickers hardness, a sheet-like material having the same component was prepared and measured using a “Fischer scope H100C” manufactured by Fischer.

The residual ratio of the insulating particles in the conductive particles with insulating particles was 75%. Moreover, the coverage which is the area of the part coat | covered with the said insulating particle which occupies for the whole surface area of the said electroconductive particle was 65%. The 10% K value at 100 ° C. of the conductive particles with insulating particles was 5680 N / mm ² .

(2) Production of conductive material 30 parts by weight of PKHC (manufactured by InChem), which is a phenoxy resin, 25 parts by weight of phenol novolac epoxy resin (“TD-2106”, manufactured by DIC) which is a thermosetting compound, and thermal cation 1 part by weight of a curing agent (“SI-60” manufactured by Sanshin Chemical Co., Ltd.), 1 part by weight of a silane coupling agent, and 10 parts by weight of the conductive particles with insulating particles are dispersed in toluene, and the solid content is 40 weights. % Resin composition was produced. This resin composition was coated on polyethylene terephthalate with a coater, and the solvent was dried to obtain an anisotropic conductive film having a thickness of 20 μm.

(3) Production of Connection Structure A transparent glass substrate (first connection target member) having a multilayer electrode pattern of Ti—Al—Ti with L / S of 15 μm / 15 μm on the upper surface was prepared. Further, a semiconductor chip (second connection target member) having a gold bump electrode pattern with L / S of 15 μm / 15 μm on the lower surface was prepared. The Vickers hardness of the gold bump in the semiconductor chip was 180.

  The obtained anisotropic conductive film was temporarily pressure-bonded and attached to the chip mounting portion on the transparent glass substrate using a temporary pressure bonding machine. Next, after laminating the semiconductor chip so that the electrodes face each other, a pressure heating head is placed on the upper surface of the semiconductor chip while adjusting the temperature of the head so that the temperature of the anisotropic conductive film becomes 180 ° C. Then, thermocompression bonding was performed by applying a pressure of 3 MPa to cure the binder resin in the anisotropic conductive film to obtain a connection structure.

  The cross section of the electrode part of the obtained connection structure was observed. As a result, it was confirmed that the insulating particles were embedded in the gold bumps of the semiconductor chip, and the nickel plating layer of the conductive particles was in contact with the gold bumps. Moreover, 3.6 insulating particles per one conductive particle with insulating particles were embedded in the gold bump. Although the insulating particles were not embedded in the electrode of the transparent glass substrate, the nickel plating layer in the conductive particles was in contact with the electrode.

  The number of insulating particles embedded in a gold bump per conductive particle with one insulating particle is such that the conductive particles and the gold bumps are in contact with each other in five conductive particles pressed onto the gold bump. The cross-section of the portion being taken was photographed with SEM while cutting 0.1 μm by FIB, the insulating particles embedded in the gold bumps were counted, and the average was obtained.

(Example 2)
(1) Conductive particles with insulating particles The conductive particles with insulating particles of Example 1 were prepared.

(2) Production of conductive material 30 parts by weight of resorcinol glycidyl ether which is a thermosetting compound, 5 parts by weight of amine adduct (“PN-23J” manufactured by Ajinomoto Fine Techno Co.) which is a thermosetting agent, and a photocurable compound 5 parts by weight of an epoxy acrylate ("EBECRYL 3702" manufactured by Daicel Ornex), 0.1 part by weight of an acylphosphine oxide compound ("DAROCUR TPO" manufactured by Ciba Japan) that is a photopolymerization initiator, and a filler 20 parts by weight of silica (average particle diameter 0.25 μm) is blended, and the conductive particles with insulating particles are further added so that the content in 100% by weight of the blend is 10% by weight. A formulation was obtained by stirring for 5 minutes at 2000 rpm using a mechanical stirrer.

  The obtained compound was filtered using a nylon filter paper (pore diameter: 10 μm) to obtain an anisotropic conductive paste having a content of conductive particles with insulating particles of 10% by weight.

(3) Production of Connection Structure A transparent glass substrate (first connection target member) having a multilayer electrode pattern of Ti—Al—Ti with L / S of 15 μm / 15 μm on the upper surface was prepared. Further, a semiconductor chip having a gold bump electrode pattern with L / S of 15 μm / 15 μm on the lower surface was prepared.

The obtained anisotropic conductive paste was applied to the chip mounting portion on the transparent glass substrate so as to have a thickness of 30 μm to form an anisotropic conductive paste layer. Next, using an LED lamp with a wavelength of 365 nm, the anisotropic conductive paste layer is irradiated with ultraviolet rays from above so that the irradiation energy is 2000 mJ / cm ^2, and the anisotropic conductive paste layer is semi-cured by photopolymerization. And B stage. Next, the semiconductor chip was stacked on the anisotropic conductive paste layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 180 ° C., a pressure heating head is placed on the upper surface of the semiconductor chip, and thermocompression bonding is performed by applying a pressure of 3 MPa. The conductive conductive paste layer was cured to obtain a connection structure.

  The cross section of the electrode part of the obtained connection structure was observed. As a result, it was confirmed that the insulating particles were embedded in the gold bumps of the semiconductor chip, and the nickel plating layer of the conductive particles was in contact with the gold bumps. In addition, 4.2 insulating particles were embedded in the gold bump electrode per one conductive particle with insulating particles. Although the insulating particles were not embedded in the electrode of the transparent glass substrate, the nickel plating layer in the conductive particles was in contact with the electrode of the transparent glass substrate.

(Example 3)
A connection structure was produced in the same manner as in Example 1 except that the average particle diameter of the plurality of silica particles adhering to the surface of the conductive particles was changed from 200 nm to 450 nm. In the obtained connection structure, when the cross section of the electrode portion of the connection structure was observed, 1.2 insulating particles per one conductive particle with insulating particles were embedded in the gold bump electrode.

Example 4
A connection structure was produced in the same manner as in Example 1 except that the average particle diameter of the plurality of silica particles adhering to the surface of the conductive particles was changed from 200 nm to 50 nm. In the obtained connection structure, when the cross section of the electrode portion of the connection structure was observed, 8.8 insulating particles per one conductive particle with insulating particles were embedded in the gold bump electrode.

(Example 5)
The surface of the silica particle was treated with silane coupling to give a vinyl group to the surface of the silica particle, and then reacted with methyl methacrylate to coat the surface with a polymer compound mainly composed of methyl methacrylate. Core-shell type particles were obtained. The core-shell particles had a silica particle diameter of 180 nm in the core portion and a polymer compound thickness of 20 nm in the shell portion. The Vickers hardness of the core-shell particles is considered to be equivalent to the hardness of the core portion because the shell portion is a thin film.

  A connection structure was produced in the same manner as in Example 1 except that the plurality of silica particles adhering to the surface of the conductive particles were changed to the core-shell type particles. When the cross section of the electrode portion of the obtained connection structure was observed, 3.4 insulating particles per one conductive particle with insulating particles were embedded in the gold bump electrode.

(Example 6)
The surface of divinylbenzene resin particles (average particle diameter 3 μm) is covered with a nickel plating layer (thickness 0.08 μm), and the outermost layer is covered with a gold plating layer (thickness 0.03 μm), and the surface of the plating layer Conductive particles with insulating particles having conductive particles having a plurality of protrusions (average height 150 nm) and a plurality of silica particles (average particle diameter 200 nm) adhering to the surface of the conductive particles. Prepared.

  Regarding the conductive particles, the gold plating layer had a Vickers hardness of 200, and the silica particles had a Vickers hardness of 1020. Regarding the Vickers hardness, a sheet-like material having the same component was prepared and measured using a “Fischer scope H100C” manufactured by Fischer.

  Furthermore, a semiconductor chip (second connection target member) having an electrode pattern in which a tin bump was coated on a copper bump having an L / S of 15 μm / 15 μm was prepared. The tin plating layer had a Vickers hardness of 30.

  A connection structure was produced in the same manner as in Example 1 except that the conductive particles with insulating particles and the second connection target member were used. When the cross section of the electrode part of the obtained connection structure was observed, 4.1 insulating particles per one conductive particle with insulating particles were embedded in the tin plating bump electrode.

(Example 7)
Conductive particles having a surface of divinylbenzene resin particles (average particle diameter 2 μm) covered with a nickel plating layer (thickness 0.08 μm) and having a plurality of protrusions (average height 150 nm) on the surface of the nickel plating layer; In addition, conductive particles with insulating particles having a plurality of silica particles (average particle diameter of 150 nm) adhering to the surface of the conductive particles were prepared. A connection structure was produced in the same manner as in Example 1 except that the conductive particles with insulating particles were used. When the cross section of the electrode part of the obtained connection structure was observed, 3.7 insulating particles per one conductive particle with insulating particles were embedded in the gold plating bump electrode.

(Comparative Example 1)
A connection structure was prepared in the same manner as in Example 1 except that the silica particles were not adhered on the surface of the conductive particles. In the obtained connection structure, when the cross section of the electrode part of the connection structure was observed, the insulating particles were not embedded in the gold bump.

(Comparative Example 2)
A connection structure was produced in the same manner as in Example 1 except that insulating particles were attached on the surface of the conductive particles instead of silica particles. The insulating particles used here are organic polymer insulating particles containing methyl methacrylate as a main component and having P—OH groups and glycidyl groups on the surface. The average particle size of the insulating particles was 200 nm. In the obtained connection structure, when the cross section of the electrode part of the connection structure was observed, the insulating particles were not embedded in the gold bump.

(Evaluation)
(1) Connection reliability against impact In the obtained connection structure, the connection resistance between the electrodes of the chip and the substrate was measured by a four-terminal method, respectively. After that, a weight of 10 cm to 100 g was dropped 5 times vertically onto the chip, and then the connection resistance was measured by the 4-terminal method, and the ratio of the electrodes with poor conduction among the 100 electrodes that were initially conducting was calculated. As a result, the connection reliability against impact was evaluated. Connection reliability against impact was determined according to the following criteria.

[Judgment criteria for connection reliability against impact]
◯: Ratio of electrodes with poor continuity is less than 1% ○: Ratio of electrodes with poor continuity is 1% or more and less than 5% △: Ratio of electrodes with poor continuity is 5% or more, 10% Less than ×: The ratio of electrodes with poor continuity is 10% or more

(2) Connection reliability against thermal shock In the obtained connection structure, connection resistance between the electrodes of the chip and the substrate was measured by a four-terminal method. Thereafter, the connection structure was put in a thermal cycle tester at −45 ° C. to 125 ° C. and a holding time of 30 minutes. After 1000 cycles, the connection resistance was measured by the four-terminal method, and the conduction reliability in the connection structure was evaluated by calculating the proportion of the electrodes that had poor conduction in the 100 electrodes that were initially conducting. The conduction reliability in the connection structure was determined according to the following criteria.

[Judgment criteria for conduction reliability in connection structure]
◯: Ratio of electrodes with poor continuity is less than 1% ○: Ratio of electrodes with poor continuity is 1% or more and less than 5% △: Ratio of electrodes with poor continuity is 5% or more, 10% Less than ×: The ratio of electrodes with poor continuity is 10% or more

  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 ... Connection part 4A ... Conductive material layer 11 ... Binder resin 21 ... Insulation Conductive particles with particles 21a ... projections 22 ... conductive particles 22a ... projections 23 ... insulating particles 31 ... base particles 32, 32A, 32B, 32C ... conductive portions 32Bx ... first conductive portions 32By ... second conductive portions 32a, 32Aa, 32Ba ... projection 33 ... core material 41, 51, 61 ... conductive particles with insulating particles 41a, 51a ... projection 42, 52, 62 ... conductive particles 42a, 52a ... projection

Claims (18)

Using conductive particles with conductive particles having conductive particles having conductive parts at least on the surface and a plurality of insulating particles arranged on the surface of the conductive particles, and a conductive material containing a binder resin, and ,
Using the first connection target member having the first electrode on the surface and the second connection target member having the second electrode on the surface,
Conductivity between the first connection target member and the second connection target member so that the conductive particles with insulating particles are located between the first electrode and the second electrode. Arranging the material;
By connecting the first connection target member and the second connection target member by thermocompression bonding, a connection portion connecting the first connection target member and the second connection target member is the conductive material. And a step of electrically connecting the first electrode and the second electrode with the conductive particles to obtain a connection structure,
At the time of the thermocompression bonding, the insulating particles located between the first electrode and the conductive particles are not embedded in the first electrode, and at the time of the thermocompression bonding, the second electrode and the The insulating particles positioned between the conductive particles are embedded in the second electrode, the insulating particles are not embedded in the first electrode, and the second electrode A method for manufacturing a connection structure, which obtains a connection structure in which insulating particles are embedded.   The method for manufacturing a connection structure according to claim 1, wherein the insulating particles are inorganic particles excluding metal particles.   The method for manufacturing a connection structure according to claim 1 or 2, wherein the insulating particles have a Vickers hardness higher than that of the second electrode.   The manufacturing method of the connection structure of any one of Claims 1-3 whose Vickers hardness of the said electroconductive part located in the surface of the said electroconductive particle is higher than the Vickers hardness of a said 2nd electrode.   The manufacturing method of the connection structure of any one of Claims 1-4 whose material of the surface electrically connected by the said electroconductive particle of a said 2nd electrode is gold | metal | money. The manufacturing method of the connection structure of any one of Claims 1-5 in which the said electroconductive particle has a processus | protrusion on the surface. Wherein as the insulating particles with the conductive particles, the compression modulus when the insulating particles with conductive particles is compressed 10% at 100 ° C. is 3000N / mm ² or more and 10000 N / mm ² or less is insulating particles with conductive The manufacturing method of the connection structure of any one of Claims 1-6 using an electroconductive particle. As the conductive particles with insulating particles, a conductive particle-containing liquid with insulating particles obtained by adding 3 parts by weight of conductive particles with insulating particles to 100 parts by weight of ethanol exceeds 20 minutes at 20 ° C. and 40 kHz. The connection according to any one of claims 1 to 7 , wherein the conductive particles with insulating particles having a residual ratio of insulating particles obtained by the following formula (1) of 50% or more when subjected to sonication are used. Manufacturing method of structure.
Residual rate (%) of the insulating particles = (coverage after ultrasonic treatment / coverage before ultrasonic treatment) × 100 (1) With the conductive particles with insulating particles, the covering ratio which is the area of the portion covered with the insulating particles in the entire surface area of the conductive particles is 40% or more and 80% or less. The manufacturing method of the connection structure of any one of Claims 1-8 using electroconductive particle. A first connection object member having a first electrode on its surface;
A second connection target member having a second electrode on its surface;
A connection portion connecting the first connection target member and the second connection target member;
The connection part includes conductive particles with insulating particles having conductive particles having at least a conductive part on a surface thereof, and a plurality of insulating particles arranged on the surface of the conductive particles, and a binder resin. It is formed using a conductive material,
The first electrode and the second electrode are electrically connected by the conductive particles;
A connection structure in which the insulating particles are not embedded in the first electrode and the insulating particles are embedded in the second electrode. The connection structure according to claim 10 , wherein the insulating particles are inorganic particles excluding metal particles. The connection structure according to claim 10 or 11 , wherein a Vickers hardness of the insulating particles is higher than a Vickers hardness of the second electrode. The connection structure according to any one of claims 10 to 12 , wherein a Vickers hardness of the conductive portion located on a surface of the conductive particles is higher than a Vickers hardness of the second electrode. The connection structure according to any one of claims 10 to 13 , wherein a material of a surface of the second electrode that is electrically connected by the conductive particles is gold. The connection structure according to any one of claims 10 to 14 , wherein the conductive particles have protrusions on a surface. The insulating particles with conductive particles, compressive modulus when the insulating particles with conductive particles is compressed 10% at 100 ° C. is 3000N / mm ² or more and 10000 N / mm ² or less is insulating particles with conductive The connection structure according to any one of claims 10 to 15 , which is a conductive particle. The conductive particles with insulating particles is a conductive particle-containing liquid with insulating particles obtained by adding 3 parts by weight of the conductive particles with insulating particles to 100 parts by weight of ethanol over 20 minutes at 20 ° C. and 40 kHz. The connection according to any one of claims 10 to 16 , which is conductive particles with insulating particles whose residual rate of insulating particles obtained by the following formula (1) is 50% or more when sonicated. Structure.
Residual rate (%) of the insulating particles = (coverage after ultrasonic treatment / coverage before ultrasonic treatment) × 100 (1) With the insulating particles, the covering ratio, which is the area of the portion covered with the insulating particles that occupies the entire surface area of the conductive particles, is 40% or more and 80% or less. The connection structure according to any one of claims 10 to 17 , which is a conductive particle.

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