JP4595981B2 - Connection member, electrode connection structure and connection method using the connection member - Google Patents

Description

  The present invention relates to a connection member that bonds and fixes an electronic component such as a semiconductor chip and a circuit board and electrically connects both electrodes, and an electrode connection structure and a connection method using the connection member.

In recent years, with the miniaturization and thinning of electronic components, circuits used for these have become denser and higher definition. Since it is difficult to connect such electronic components and fine electrodes with conventional solders or rubber connectors, anisotropically conductive adhesives and membranes with excellent resolution (hereinafter referred to as connecting members) Is frequently used. This connecting member is made of an adhesive containing a predetermined amount of a conductive material such as conductive particles. This connecting member is provided between an electronic component and an electrode or a circuit, and pressure or heating / pressing means are taken. The electrodes are electrically connected to each other, and the electrodes formed adjacent to the electrodes are provided with insulating properties so that the electronic component and the circuit are bonded and fixed. The basic idea for increasing the resolution of the connecting member is to ensure the insulation between the adjacent electrodes by making the particle size of the conductive particles smaller than the insulating part between the adjacent electrodes, and also to contain the conductive particles. The amount is set so that the particles do not come into contact with each other and is surely present on the electrode to obtain conductivity at the connection portion.
JP-A-61-195179 JP-A-4-366630

  In the conventional method, when the particle size of the conductive particles is reduced, the particles are secondarily agglomerated due to a significant increase in the particle surface area, and the insulation between the adjacent electrodes cannot be maintained. In addition, if the content of the conductive particles is reduced, the number of conductive particles on the electrodes to be connected also decreases, so the number of contact points is insufficient and conduction between the connection electrodes cannot be obtained. It has been extremely difficult to increase the resolution of the connecting member. In other words, due to the recent significant increase in resolution, that is, the electrode area and the miniaturization between adjacent electrodes (spaces), the conductive particles on the electrodes flow out between the adjacent electrodes together with the adhesive by the pressurization or heating and pressurization during connection, This hinders high resolution of the connecting member. At this time, in order to suppress the outflow of the adhesive, if the adhesive has a high viscosity, the contact between the electrode and the conductive particles becomes insufficient, and it becomes impossible to connect the opposing electrodes. On the other hand, if the adhesive has a low viscosity, in addition to the outflow of the conductive particles, there is a drawback in that bubbles are likely to be included in the space portion and connection reliability, particularly moisture resistance is lowered.

  Therefore, a connection member having a multilayer structure in which the conductive particle-containing layer and the insulating adhesive layer are separated from each other, and the viscosity at the time of connecting the conductive particle-containing layer is relatively higher than that of the insulating adhesive layer or higher cohesive force. Thus, attempts to hold the conductive particles on the electrode by making the conductive particles difficult to flow can be seen in, for example, Japanese Patent Application Laid-Open Nos. 61-195179 and 4-366630. However, since the conductive particle-containing layer has a higher viscosity than the insulating adhesive layer at the time of connection, the contact between the electrode and the conductive particles becomes insufficient, and the connection resistance value is high, so the connection reliability is unsatisfactory. . In addition, in order to reduce the connection resistance value, if conductive particles are exposed in advance from the conductive particle-containing layer to facilitate contact with the electrode, it is necessary to increase the particle size of the conductive particles, which corresponds to higher resolution. Can not. In addition, there is also a proposal of a connection member having a conductive particle dense region in a necessary part in both directions as a connection member capable of connecting such fine electrodes and circuits and having excellent connection reliability. According to this, although a dot-shaped fine electrode such as a semiconductor chip can be connected, there is a disadvantage that the precise alignment between the conductive particle dense region and the dot-shaped electrode is necessary and the workability is inferior.

  The present invention has been made in view of the above-described drawbacks, and since the conductive particles are difficult to flow out from the electrode during connection, the conductive particles can be held on the electrode, and contact between the electrode and the conductive particles can be easily obtained. The present invention relates to a high-resolution connection member useful for connecting semiconductor chips, which is excellent in connection reliability for a long time because it is difficult to include, and does not require accurate alignment between conductive particles and electrodes. That is, according to our study (detailed in the Examples section below), regarding the retention of the conductive particles on the electrode after connection, the configuration of the multilayer connection member and the ratio of the major axis to the minor axis of the electrode connection surface It was found that there was a very characteristic fact in (L / D), and the present invention was reached.

  A first aspect of the present invention is a multilayer connection member in which an insulating adhesive layer is formed on at least one surface of an adhesive layer having conductivity in a pressurizing direction composed of a conductive material and a binder. The present invention relates to a connection member for semiconductor chips, wherein the melt viscosity is equal to or less than that of an insulating adhesive layer. Here, the melt viscosity at the time of connection of the binder component is 500 poises or less, and the binder and the insulating adhesive layer are mainly composed of an epoxy resin modified with a high molecular weight epoxy resin or a styrene-ethylene-butylene-styrene block copolymer. It is preferable to do.

The second aspect of the present invention is a connection structure between electrode rows in which at least one of the opposed electrode rows protrudes, and the electrode rows are connected via a connecting member, and the connecting member is a conductive material. A multi-layer connection member in which an insulating adhesive layer is formed on at least one surface of an adhesive layer having conductivity in the pressurizing direction consisting of a binder and an insulating adhesive layer when the binder component is connected. The conductive material is a conductive particle or an insulating coating particle formed by forming an insulating coating on the surface of the conductive particle, and the number of effective particles contributing to the connection on the electrode converted to 50 μmφ is The present invention relates to an electrode connection structure characterized in that there are ten or more and an insulating adhesive layer covers at least the periphery of the protruding electrode on the substrate side. Here, the electrode connection structure is preferably an electrode connection structure characterized in that the density of the conductive material is inclined and thin from the top of the protruding electrode to the substrate side.

  According to the present invention, since the melt viscosity at the time of connecting the binder component is equal to or less than that of the relatively insulating adhesive layer, there is little outflow from the electrode. Therefore, it is possible to provide a connection member with high resolution and excellent connection reliability, an electrode connection structure and a connection method using the connection member.

  The present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a connecting member for explaining an embodiment of the present invention. The connection member of the present invention is a multilayer connection member in which an insulating adhesive layer 2 is formed on at least one surface of a conductive adhesive layer 1 having conductivity in a pressing direction composed of a conductive material and a binder. As shown in FIG. 2, the insulating adhesive layer 2 may be formed on both surfaces of the conductive adhesive layer 1. Although not shown in FIGS. 1-2, you may add functions, such as adhesiveness, to the insulating contact bonding layer 2 as a multilayer structure further. In order to prevent unnecessary adhesion such as stickiness and dust on these surfaces, a peelable separator 5 as shown in FIG. 1 can be present as required. Although not shown, the separator 5 can be formed on both sides. In the case of FIG. 1, since the separator 5 is in contact with the insulating adhesive layer 2, for example, in the case of temporary attachment when the substrate on one side is a flat electrode, the conductive adhesive layer in which the separator 5 does not exist on the flat electrode side with less unevenness. Since 1 can be formed, the connection is easy and the workability is good and convenient. In these cases, the continuous tape shape is preferable because continuous automation of the connection work process can be achieved.

  FIG. 3 is a schematic cross-sectional view illustrating the conductive adhesive layer 1 having conductivity in the pressing direction. The conductive adhesive layer 1 is made of a binder 4 containing a conductive material 3. Here, as the conductive material 4, those shown in FIGS. 3A to 3G are applicable. Among these, the conductive material 3 has a particle size that can exist in a single layer in the thickness direction of the binder 5 as shown in FIGS. 3C to 3E, that is, a particle size substantially equal to the thickness of the binder 5. Since the conductive material 3 does not easily flow at the time of connection, the conductive material 3 is preferable to be easily held on the electrode. When the conductive material 3 is substantially equal to the thickness of the binder 4, it is possible to conduct electricity with the electrode by simple contact, and conductivity is easily obtained. The ratio of the conductive material 3 to the binder 4 is preferably about 0.1 to 20% by volume, and more preferably 1 to 15% by volume, because anisotropic conductivity is easily obtained. Further, in order to easily obtain conductivity in the thickness direction and to achieve high resolution, the thickness of the binder 5 is preferably as thin as possible in the range where a film can be formed, and is preferably 20 μm or less, more preferably 10 μm or less. For example, the conductive material 3 is preferably formed of conductive particles as illustrated in FIGS. 3A to 3E because the manufacturing is relatively easy. Further, the conductive material 3 may be provided with a through hole in the binder 5 as shown in FIG. 3 (f) to form a conductor by plating or the like, or may be in the form of a conductive fiber such as a wire as shown in FIG. 3 (g). .

  Examples of the conductive particles include metal particles such as Au, Ag, Pt, Ni, Cu, W, Sb, Sn, and solder, carbon, and the like. These conductive particles are used as a core material, or non-conductive glass, A core material made of a polymer such as ceramics or plastic may be coated with a conductive layer made of the above-described material. Furthermore, insulating coating particles formed by coating the conductive material 6 with an insulating layer, and combined use of conductive particles and insulating particles such as glass, ceramics, and plastics are applicable because the resolution is improved. In order to secure one or more particles, preferably as many particles as possible, on a minute electrode, a small particle size of 15 μm or less is suitable, and more preferably 7 μm or less and 1 μm or more. If it is 1 μm or less, it is difficult to break through the insulating adhesive layer and contact the electrode. In addition, it is preferable that the conductive material 3 has a uniform particle diameter because there is little outflow from between the electrodes. Among these conductive particles, those in which a conductive layer is formed on a polymer core material such as plastic, and hot-melt metal such as solder are deformable by heating or pressurization, and contact with the circuit at the time of connection This is preferable because the area is increased and the reliability is improved. In particular, when a polymer is used as a nucleus, it does not show a melting point like solder, so that the softening state can be widely controlled by the connection temperature, and it is easy to cope with variations in electrode thickness and flatness, which is particularly preferable. Also, for example, in the case of hard metal particles such as Ni and W, or particles having a large number of protrusions on the surface, the conductive particles pierce the electrode and the wiring pattern, so that even when an oxide film or a contaminated layer exists, a low connection resistance is obtained. It is preferable because it is obtained and reliability is improved.

  For the binder 4 and the insulating adhesive layer 2, a thermoplastic material or a material that exhibits curability by heat or light can be widely applied. These are preferably highly adhesive. Among these, application of a curable material is preferable because of excellent heat resistance and moisture resistance after connection. Among these, an epoxy adhesive is particularly preferable because it can be cured for a short time, has good connection workability, and has excellent molecular adhesion. Epoxy adhesives are mainly composed of epoxy modified with high molecular weight epoxy, solid epoxy and liquid epoxy, urethane, polyester, acrylic rubber, NBR, silicone, nylon, etc., curing agent, catalyst, coupling agent, filling A material obtained by adding an agent or the like is generally used. When the binder component 4 and the insulating adhesive layer 2 of the present invention contain 1% or more, preferably 5% or more of a common material in each component, the interfacial adhesive force between the two layers is improved, which is suitable. As the common material, a main material, a curing agent, and the like are more effective.

  In the present invention, the melt viscosity at the time of connecting the binder component is equal to or less than that of the insulating adhesive layer. This point will be described with reference to FIGS. FIG. 4 is a schematic explanatory diagram showing the melt viscosity during heating of the binder component 4 and the insulating adhesive layer 2. In the present application, the binder component 4 (A) is relatively equal to or less than that of the insulating adhesive layer 2 (B) at the temperature at the time of connection, and preferably the difference in viscosity between (A) and (B) at this time Is about 0.1 to 1000 poise, more preferably 1 to 200 poise. If the difference in viscosity is too large, the contact between the electrode and the particles tends to be insufficient. As will be described later with reference to FIG. 5, there is a preferable viscosity range in order to hold the particles on the electrode and to effectively obtain the contact between the electrode and the particle from the balance between the contact at the time of connection and the flow process. For the same reason, the melt viscosity at the time of connection is preferably such that the binder component is 500 poise or less, and at this time, the insulating adhesive layer is more preferably 1000 poise or less.

  In the contact process shown in FIG. 5A, first, the conductive material 3 is relatively embedded in the insulating adhesive layer 2 having a relatively high melt viscosity or is partially trapped. Retained. Next, in the flow process of FIG. 5B, the conductive material 3 comes into contact with the protruding electrode 12 by the softening of the insulating adhesive layer, and can conduct electricity with the planar electrode 13. In the case of a preferred embodiment in which the melt viscosity at the time of binder component connection is lower than that of the insulating adhesive layer, the insulating adhesive layer 2 can hold the conductive material 3 and the spaces between adjacent protruding electrodes are bubbles. It can be connected in the state without. In this case, in order to promote softening of the insulating adhesive layer 2, the insulating adhesive layer of the connecting member is disposed on the protruding electrode side, a heat source is disposed on the insulating adhesive layer side, and heating and pressing are further performed. preferable. At this time, it is also possible to divide the heating and pressurizing process into two or more stages and to make an electrode connection method including an energization inspection process and / or a repair process as necessary. By decomposing the heating and pressurizing step into two or more steps, it is possible to control the viscosity of the flow process associated with the curing reaction of the adhesive, and therefore, a good connection without bubbles is possible. In addition, it is possible to impart repairability, which is a problem with curable adhesives.

  The energization inspection step can be performed while increasing the cohesive force of the connection member to the extent that the connection electrode can be held, or while pressurizing the electrode connection portion. The through electrode inspection can be performed, for example, by taking out lead wires from both electrodes and measuring a connection resistance or an operation test. At this time, the appearance inspection of the contact state between the conductive material 3 and the electrode can also be performed together or independently. Repairability is to remove unnecessary part of the adhesive, clean it with a solvent, and reconnect. In general, a curable adhesive has been regarded as a problem because a network structure develops after curing, becomes insoluble and infusible with heat, solvent, and the like, and is extremely difficult to clean. In the first stage of the heating and pressurizing process, for example, the conductive material 3 is in contact with the protruding electrode 12, and an energization inspection of both electrodes is performed in a state where the conductive material 3 can conduct with the flat electrode 13. At this time, if there is a connection portion of a defective electrode, repair and reconnection are performed in this state. Since the adhesive is uncured or has an insufficient curing reaction, it is easy to peel off and soak in a solvent, and repair work is easy.

  The method for measuring the melt viscosity is not particularly limited as long as the binder component 4 and the insulating adhesive layer 2 can be relatively compared with each other. However, it is preferable to use the same method, for example, a general method capable of measuring at high temperatures. A rotary viscometer can be used. At this time, in the case of, for example, thermosetting blending in which the reaction proceeds at the time of measurement and the viscosity changes, the measured value in the model blending with the curing agent removed can be adopted. As a method of providing a difference in melt viscosity at the time of connection between the binder component 4 and the insulating adhesive layer 2, a combination of the intrinsic viscosity depending on the molecular weight of the material and the entanglement of the molecules, selection of a filler as a thickener, and curing Control of the difference in reaction rate in the system is common. As a manufacturing method of the connection part material of this invention, the method of laminating | stacking the conductive contact bonding layer 1 and the insulating contact bonding layer 2, for example, laminating | stacking and applying sequentially is employable.

  An electrode connection structure using the connection member of the present invention and a manufacturing method thereof will be described with reference to FIGS. FIG. 6 shows a structure in which the protruding electrode 12 formed on the chip substrate 11 and the planar electrode 14 of the substrate 13 are connected via the connecting member of the present invention. That is, it is a connection structure between electrode rows in which at least one of the opposed electrode rows protrudes, and the conductive material 3 exists between the opposed electrodes 12-14 and is more conductive than the periphery 15 of the protruding electrode 12. The density of the material exists in a high state, and the electrode rows facing each other are connected. The insulating adhesive layer 2 covers at least the periphery 15 of the protruding electrode 12 protruding. Here, the planar electrode 14 refers to a case where there is no unevenness from the surface of the substrate 11 or even a few μm or less. When these are illustrated, the electrodes obtained by the additive method and the thin film method are typical.

  FIG. 7 shows a case where the electrodes formed on the substrate are the protruding electrodes 12 and 12 '. That is, this is a structure in which both surfaces shown in FIG. 2 are connected via the connecting member having the insulating adhesive layers 2 and 2 ′. The insulating adhesive layers 2 and 2 'cover the periphery of the protruding electrodes 12 and 12', and are in contact with the chip substrate surface 11 and the substrate surface 13, respectively. FIG. 8 shows the case where the electrodes formed on the substrate are the protruding electrode 12 and the concave electrode 16. In this case as well, the concave electrode 16 can be replaced with the planar electrode 14 shown in FIG. Here, as an example of the concave electrode 16, there is, for example, an Al pad before the protruding electrode (bump) of the semiconductor chip is formed, and an unnecessary portion is covered with the insulating layer 18. The insulating layer 18 is made of silica, silicon nitride, polyimide or the like, and generally has a thickness of several μm. In the case of FIG. 8, it is not necessary to form protruding electrodes on the chips, and the cost can be reduced.

  6 to 8 show the case where the conductive adhesive layer 1 and the insulating adhesive layer 2 form a boundary, the two layers may be mixed, and the protruding electrode 12 as shown in FIG. A configuration in which the density of the conductive material 3 is gradually reduced from the top portion 17 to the substrate 11 side may be employed. 6 to 8, the chip substrate 11 includes semiconductors such as silicon, gallium arsenide, gallium phosphorus, crystal, sapphire, garnet, and ferrite. Examples of the substrate 13 include plastic films such as polyimide and polyester, composites such as glass fiber / epoxy, semiconductors such as silicon, inorganic materials such as glass and ceramics, and the like. The protruding electrode 12 can include various circuits and terminals in addition to the bumps. The various electrodes shown in FIGS. 6 to 8 can be applied in any combination. Here, the protruding electrode 12 of the chip substrate 11 has a ratio of the major axis to the minor axis (L / D) of the connecting electrode surface of the semiconductor chip of 20 or less, and more preferably 1 to 10. This is because the retention property of the conductive particles on the electrode after connection using the connection member of the present invention is good within the above range of L / D.

  Regarding the retention of conductive particles on the electrode after connection, the reason for the existence of extremely characteristic facts in the structure of the multilayer connection member and the ratio of the major axis to minor axis (L / D) of the electrode connection surface is sufficient. Although not clarified, it is considered to be an influence of the directionality and heat transfer when the adhesive flows. The electrode connecting method using the connecting member of the present invention is arranged so that the insulating adhesive layer 2 of the connecting member is on the protruding electrode 12 side, and the melt viscosity at the time of connecting the binder component and the insulating adhesive layer. However, it is heated and pressurized under a condition in which the binder component is relatively lower than the insulating adhesive layer.

[Action]
According to the present invention, since the melt viscosity at the time of connecting the binder component is equal to or less than that of the insulating adhesive layer, the conductive material 3 of the conductive adhesive layer 1 has relatively the same melt viscosity at the time of electrode connection. The conductive material 3 is held on the protruding electrode 12 by being embedded in the insulating adhesive layer 2 or in contact with a part of the insulating adhesive layer 2 being captured. Next, due to the softening flow of the insulating adhesive layer, the conductive material 3 comes into contact with the protruding electrodes 12 and becomes conductive. At this time, the insulating adhesive layer 2 has a higher viscosity than the binder component 4, can hold the conductive material 3, and can connect a space portion between adjacent protruding electrodes without bubbles. According to the present invention, when the ratio of the major axis to the minor axis (L / D) of the connecting electrode surface of the semiconductor chip or the like is small, a large amount of the conductive material 3 is securely held on the minute protruding electrode 12, so that the connection is achieved. Since highly reliable and expensive conductive materials can be efficiently applied, resource saving is achieved.

  According to the present invention, since the conductive material 3 is reliably held on the protruding electrode 12 and can be conducted, the reliability of the conduction test is improved. Since the adhesive can be inspected for continuity in an uncured state or in an insufficient curing reaction, the repair work is easy. Since the insulating adhesive layer 2 is disposed so as to be on the protruding electrode 12 side, the insulation and resolution between adjacent electrodes are improved. In addition, when the insulating adhesive layer 2 has a high melt viscosity, the connection pressure is not applied, so that the conductive material 3 is less likely to flow between adjacent electrodes. Since the conductive material 3 of the conductive adhesive layer 1 is uniformly dispersed over the entire surface, it is excellent in workability because accurate alignment between the conductive particles and the electrodes is unnecessary. Depending on the purpose of the adhesive layer, for example, a combination that exhibits adhesion suitable for the material of the electrode substrate is possible, so that the choice of materials is expanded, and the connection reliability is also improved due to the reduction of bubbles in the connection portion. Further, by making one of them soluble or swellable in a solvent or having a difference in heat resistance, it is possible to preferentially peel off from one substrate surface and to impart so-called repairability for reconnection. Alternatively, any combination suitable for the material of the electrode substrate is possible, and it is easy to obtain contact between the electrode and the conductive particles, and the manufacturing method is also simple. Further, it is possible to obtain a reinforcing or moisture-proof effect by causing the adhesive layer to protrude outside the connecting portion and acting as a sealing material.

  Further, the present invention is a connection structure between electrode rows in which at least one of the opposed electrode rows protrudes, wherein the conductive material exists between the opposed electrodes, and the insulating adhesive layer is at least a substrate of the protruding electrode. The present invention relates to an electrode structure characterized by covering the periphery of the side. Further, the present invention is arranged such that the insulating adhesive layer of the connecting member is on the protruding electrode side between the opposing electrode rows having at least one protruding electrode, and the binder component and the insulating adhesive layer The present invention relates to a method for connecting electrodes, characterized in that the melt viscosity at the time of connection is heated and pressurized under a condition that the binder component is relatively lower than that of an insulating adhesive layer. Furthermore, the present invention relates to a connection method in which the insulating adhesive layer is disposed on the protruding electrode side and is heated and pressed, and the heating and pressing step is divided into two or more stages, and the connection electrode energization inspection step and The present invention relates to a method for connecting electrodes, wherein a repair process is performed as necessary.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Example 1
(1) Preparation of conductive adhesive layer The ratio of phenoxy resin (high molecular weight epoxy resin) and liquid epoxy resin (epoxy equivalent 185) containing a microcapsule type latent curing agent is 30/70, and a 30% solution of ethyl acetate Got. To this solution, 8% by volume of conductive particles in which a Ni / Au metal coating having a thickness of 0.2 / 0.02 μm was added to polystyrene particles having a particle diameter of 4 ± 0.2 μm was added and mixed and dispersed. This dispersion was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater and dried at 110 ° C. for 20 minutes to obtain a conductive adhesive layer having a thickness of 5 μm. The viscosity of the model blend from which the curing agent of the adhesive layer was removed was measured with a digital viscometer HV-8 (manufactured by Reska Co., Ltd.). The viscosity at 150 ° C. was 80 poise.

(2) Formation of Insulating Adhesive Layer and Connection Member Preparation (1) The blending ratio of 40/60 is set to 40/60, and the conductive particles are removed from the conductive adhesive layer. did. First, the conductive adhesive layer surface (1) and the adhesive layer surface (2) were laminated while being rolled between rubber rolls. Thus, a multilayer connection member having a thickness of 20 μm in the two-layer configuration of FIG. 1 was obtained. The viscosity at 150 ° C. of the insulating adhesive layer measured in the same manner as described above was 280 poise. Therefore, the difference in viscosity between the conductive adhesive layer and the insulating adhesive layer at 150 ° C. is 200 poise.

(3) IC chip for connection evaluation (silicon substrate, 2 × 12 mm, height 0.5 mm, 300 gold electrodes 50 μmφ called 20 μm height called bumps are formed on two long sides) and glass 1.1 mm A flat electrode having a thin film circuit with an indium oxide thickness of 0.2 μm (ITO, surface resistance 20Ω / □) was connected to the upper surface. The ITO electrode on the glass side was made to correspond to the bump electrode size of the IC chip, and a measurement lead was drawn around. The connecting member was cut into 2.5 × 14 mm slightly larger than the size of the IC chip, and temporarily connected such that the conductive adhesive layer was on the flat electrode side. In addition to the smoothness of the substrate, it was easy to attach due to the adhesiveness of the connecting member, and the subsequent peeling of the separator was also easy. Next, the bump of the IC chip and the planar electrode were aligned, and heated and pressed at 150 ° C., 30 kgf / mm ² for 15 seconds to obtain a connection body. At this time, the heat source of the connecting device was disposed on the insulating adhesive layer side, and the conductive adhesive layer was disposed on the planar electrode side.

(4) Evaluation When the cross section of this connection body was polished and observed with a microscope, it was a connection structure corresponding to FIG. The space between adjacent electrodes was free of bubbles and the particles were spherical, but the particles were compressed and deformed on the electrodes and held in contact with the upper and lower electrodes. When the resistance between the electrodes facing each other was evaluated as the connection resistance, and the insulation resistance between the adjacent electrodes was evaluated, the connection resistance was 1Ω or less, and the insulation resistance was 1010Ω or more. Good long-term reliability. The number of effective average particles contributing to the connection on the electrode (50 μmφ = 1962.5 μm ² ) in this example was 20 (maximum 23 particles, minimum 18 particles, and so on). The effective particles contributing to the connection were observed by observing the connection surface from the glass side with a microscope (× 100) and having gloss due to contact with the electrode. Since L / D is 50 μmφ (diameter), it is 1.0. In this example, the particles on the bumps were compressed and deformed and held in contact with the upper and lower electrodes. Air bubbles were not mixed between adjacent bumps, and good long-term reliability was demonstrated. The conductive particles have different degrees of deformation of the particles depending on the variation in the distance between the opposing electrodes, and some of the conductive particles bite into the bumps, and good connection was obtained in all the electrodes.

Comparative Example 1
Although it was the same as that of Example 1, a single-layer conductive adhesive layer having a conventional structure with a thickness of 20 μm was obtained. When evaluated in the same manner as in Example 1, the number of particles on the electrode (50 μmφ) was 13 at the maximum and 0 at the minimum, and there were no effective particles on the electrode, and the maximum and the minimum as compared with Example 1. The variation of was large. Further, when the insulation resistance of the connection body was measured, a short circuit defect occurred. It seems that the conductive particles flowed out from the electrodes at the time of connection, and the insulation between adjacent electrodes (space portions) cannot be maintained.

Example 2
Similarly, an insulating adhesive layer was formed on the other surface of the conductive adhesive layer of Example 1 to obtain a multi-layer connecting member having a three-layer structure shown in FIG. Moreover, it replaced with the glass plane electrode of Example 1, and was set as the 2 layer FPC circuit board which has a 18 micrometers high copper circuit on a polyimide film. Connections were made in the same manner as in Example 1 to obtain a connection body corresponding to FIG. When evaluated in the same manner as in Example 1, good connection characteristics were shown. The number of effective particles on the electrodes can be secured to 10 or more in all the electrodes regardless of the configuration in which the particles easily flow out because of the connection between the protruding electrodes.

Examples 3-5 and Comparative Examples 2-3
Although it is the same as that of Example 1, the difference in the viscosity at 150 ° C. of both layers was changed by changing the blending ratio of the phenoxy resin and the liquid epoxy resin of the insulating adhesive layer. The results are shown in Table 1 together with Example 1 described above. In each example, the number of effective particles on the electrode was large and the variation was relatively small, and good connection characteristics were exhibited as in Example 1. In Comparative Example 2, since the difference in viscosity was too large, the conductive particles could not be exposed from the insulating adhesive layer, and no effective particles were seen on the electrode, and connection was impossible. Comparative Example 3 is a conventionally known two-layer structure in which the structure of the connecting member is reversed from that of Example 1. However, the number of effective particles is small and there is no effective particle on the electrode. Compared to 1, the maximum and minimum variations were large.

Comparative Examples 4-5
The FPC circuit boards of Example 2 were connected as parallel electrode connections (electrode width D = 50 μm, connection width L = 1500 μm, L / D = 30). Comparative Example 4 is a connection using the connection member of Example 1, but the number of effective particles on the electrode converted to 50 μmφ was 9 (0 to 16), which was 1/2 or less compared to Example 1. Comparative Example 5 is a connection using the connection member of Comparative Example 3, but the number of effective particles was 18 (14 to 24), which was improved as compared with Comparative Example 3. From these results, the optimum configuration of the connecting member differs between the connection of parallel electrodes such as a circuit board having a large L / D and the case of dot-shaped electrodes having a small L / D such as a semiconductor chip electrode. I understood. Although the reason for this is unknown, it is considered that the heat transfer property at the time of connection and the flow of the adhesive change due to the influence of L / D.

Examples 6-8
Although it is the same as that of Example 1, the bump shape of the IC chip connection surface was changed. The long diameter of the bump was directed to the center of the IC chip. The results are shown in Table 2. In each example of L / D = 1 to 10, the number of effective particles on the electrode was large and the variation was relatively small, and good connection characteristics were shown as in Example 1.

Reference example 1
Similar to Example 1, but no bumps on the IC chip connection surface were formed. That is, the semiconductor chip is a concave electrode in which a pad is formed in a necessary portion of the Al wiring and the other than the pad is covered with an insulating layer having a thickness of 1 μm (in this case, SiO ₂ ), and has the configuration of FIG. In this case, the conductive adhesive layer side was temporarily connected to the semiconductor chip. In this reference example, good connection characteristics were exhibited in the same manner as in Example 1, and it was unnecessary to form a protruding electrode on the chips, which was very economical.

Example 9
Although it is the same as that of the connection member of Example 2, the particle diameter of electroconductive particle was 7 micrometers and the electroconductive contact bonding layer thickness was 7 micrometers. The thickness of the insulating adhesive layer was 25 μm on one side and 50 μm on the other side. The electrodes were QFP type IC leads (thickness: 100 μm, pitch: 300 μm, electrode width: 350 μm, connection width: 3000 μm, L / D = 8.6), and were connected to a copper terminal having a thickness of 35 μm on the glass epoxy substrate. This configuration is similar to that shown in FIG. 7, but has no substrate on the lead side (one side) of the IC. In this example, the electrodes were connected to each other with a large height, but there was no electrode displacement and good connection characteristics were shown. Although the conductive material in the conductive sheet is not shown, the particles were compressed and deformed and held in contact with the upper and lower electrodes. Air bubbles were not mixed between adjacent electrodes, and good long-term reliability was demonstrated. In this example, the adhesive layer was formed along the lead height even in the portion without the substrate, and the lead could be fixed. The number of effective particles on the electrode could be 10 or more for all electrodes.

Examples 10-11
Although it is the same as that of Example 1, it changed into the board | substrate which can mount five IC chips on a glass substrate, and made the heating-pressing process into two steps. First, the connection resistance at each connection point was measured and inspected with a multimeter while applying pressure after 2 seconds at 150 ° C. and 20 kgf / mm ² (Example 10). Similar but the other was removed from the connecting device after 150 seconds at 20 ° C. and 20 kgf / mm ² . Since the cohesive force of the adhesive was improved by heating and pressing, each IC chip could be temporarily fixed on the glass side and was similarly tested without pressure (Example 11). In both examples, one IC chip was abnormal. Therefore, when the abnormal chip was peeled off and the same connection as described above was performed with a new chip, both were good. In both examples, since the adhesive was in a state where the curing reaction was insufficient, peeling of the chip and subsequent cleaning with acetone were extremely simple, and repair work was easy. After the above energization inspection process and repair process, when connected at 150 ° C., 20 kgf / mm ² for 15 seconds, both examples showed good connection characteristics. The number of effective particles on the bumps could be 19 or more for all the electrodes. In the present embodiment, the number of effective particles on the bumps is increased and the outflow from the electrodes is less than that in the first embodiment. Since the heating and pressurizing process is in two stages, it is considered that the retention of particles is further improved.

Example 12
Although it is the same as that of the connection member of Example 1, carbonyl nickel (average particle diameter of 3 μm) having conductive particles on the surface was used, the addition amount was 4% by volume, and the thickness of the conductive adhesive layer was changed to 5 μm. The insulating adhesive layer has a thickness of 20/80 as the ratio of carboxyl-modified SEBS (styrene-ethylene-butylene-styrene block copolymer) and a liquid epoxy resin (epoxy equivalent 185) containing a microcapsule type latent curing agent. A 15 μm sheet was prepared in the same manner as described above, and laminated with the conductive adhesive layer surface. Similarly, the viscosity at 150 ° C. was 100 poise. Therefore, the difference in viscosity between the conductive adhesive layer and the insulating adhesive layer is 20 poise. As a result of evaluation in the same manner as in Example 1, the tip of the conductive particles bite into the electrode, and the number of effective particles on the electrode was 100 or more. Good connection resistance, insulation resistance, and long-term reliability. In this example, since the polymer component was changed between the conductive adhesive layer and the insulating adhesive layer, it could be cleanly peeled off from the surface on the insulating adhesive layer side after bonding. This means the ease of repair work. The Tg (glass transition point) determined by the TMA (thermomechanical analysis) tensile method between the conductive adhesive layer and the insulating adhesive layer was 125 ° C. for the former and 100 ° C. for the latter. This is effective for the peeling work because it can be peeled off using the difference in heat resistance of the adhesive layer when the peeling temperature is set high in the repair work, and it is easy to provide a difference in cohesive force.

Reference Examples 2-4
Although it is the same as the connection member of Example 1, 1 volume% of the polystyrene-type particle | grains which are the cores of the electroconductive particle of Example 1 as an insulating particle, a conductive contact bonding layer (reference example 2), an insulating contact bonding layer ( Reference Example 3) and both layers (Reference Example 4) were mixed and dispersed. When evaluated in the same manner as in Example 1, the connection resistance, insulation resistance, and long-term reliability were all good. Since the amount of insulating particles added was small, no effect on fluidity was observed in each reference example. In Reference Example 2, the insulating particles were dispersed between the conductive particles, which was effective in improving the anisotropic conductivity resolution of only the conductive adhesive layer. Reference Example 3 was effective for maintaining the insulating property of the insulating adhesive layer, and Reference Example 4 had the characteristics of both Reference Examples 2 and 3. The insulating particles of Reference Examples 2 and 4 were deformed and held between the electrodes in the same manner as the conductive particles.

Example 13
Although it is the same as that of the connection member of Example 1, the surface of the conductive particles was subjected to an insulation coating treatment. That is, the surface of conductive particles having an average particle diameter of 4 μm was covered with a nylon resin having a glass transition point of 127 ° C. to a thickness of about 0.2 μm, and the amount added was increased to 15% by volume. Evaluation was performed in the same manner as in Example 1, but good connection characteristics were exhibited. In this example, the number of particles on the electrode increased significantly. The electrode connection can be conducted by softening the insulating layer and the binder due to the thermal pressure at the time of connection, but the space part of the adjacent electrode row has little heat pressure and the surface of the conductive material is still covered with the insulating layer. The property was also good. The number of effective particles on the bump could be 30 or more for all electrodes. In this structure, the density | concentration with respect to the binder of an electroconductive material was able to be comprised with high density.

The cross-sectional schematic diagram which shows the connection member of this invention. The cross-sectional schematic diagram which shows the other connection member of this invention. The cross-sectional schematic diagram which shows the electroconductive contact bonding layer in this invention. The diagram which shows the melt viscosity of the adhesive bond layer in this invention. Explanatory drawing (a) (b) which shows the connection process in this invention. The cross-sectional schematic diagram which shows the example of a connection structure of the electrode using the connection member of this invention. The cross-sectional schematic diagram which shows the example of a connection structure of the electrode using the connection member of this invention. The cross-sectional schematic diagram which shows the example of a connection structure of the electrode using the connection member of this invention. The cross-sectional schematic diagram which shows the example of a connection structure of the electrode using the connection member of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Conductive adhesive layer, 2 ... Insulating adhesive layer, 3 ... Conductive material, 4 ... Binder, 5 ... Separator, 11 ... Chip substrate, 12 ... Projection electrode, 13 ... Substrate, 14 ... Planar electrode, 15 ... Surrounding, 16 ... concave electrode, 17 ... top, 18 ... insulating layer.

Claims (3)

It is a connection structure between electrode rows in which at least one of the electrode rows facing each other protrudes,
The electrode rows are connected via a connecting member, and the connecting member is formed by forming an insulating adhesive layer on at least one side of the adhesive layer having conductivity in the pressurizing direction composed of a conductive material and a binder. It is a multilayer connection member, and the melt viscosity at the time of connection of the binder component is equal to or less than that of the insulating adhesive layer,
The conductive material is a conductive particle or an insulating coating particle formed by forming an insulating coating on the surface of the conductive particle, and the number of effective particles contributing to the connection on the electrode converted to 50 μmφ is 10 or more,
And an insulating adhesive layer covering at least a substrate side of the protruding electrode.   2. The electrode connection structure according to claim 1, wherein the density of the conductive material is gradually reduced from the top of the protruding electrode to the substrate side. The electrode connection structure according to claim 1, wherein the binder component or the insulating adhesive layer is formed of a heat or photocurable material.

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