JP2006339160A - Thermosetting circuit connection member, electrode connection structure using the same, and electrode connection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent long-term connection reliability in which conductive particles do not easily flow out from an electrode at the time of connection and can be held on the electrode, and contact between the electrode and the conductive particle is easily obtained, and bubbles are not easily included in a connection part. A high-resolution thermosetting circuit connection member useful for connection between electrodes, which does not require accurate alignment between conductive particles and electrodes and has excellent workability, and an electrode connection structure and connection method using the same provide.
An epoxy resin and a phenoxy resin are formed as an insulating adhesive layer on at least one surface of a conductive adhesive layer having a conductive material and an epoxy resin and a phenoxy resin as a binder and having conductivity in a pressurizing direction. A thermosetting circuit connecting member comprising an insulating adhesive layer having a melt viscosity equivalent to that of the conductive adhesive layer.
[Selection] Figure 1

Description

  The present invention relates to a thermosetting circuit connecting 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 connecting structure and a connecting method using the thermosetting circuit connecting 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, and this connecting member is provided between the electronic component and the electrode or circuit to form a pressurizing or heating / pressing means. As a result, 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 portion between the adjacent electrodes. 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.

  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 at the time of 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.

JP-A-61-195179 JP-A-4-366630

  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.

In the first aspect of the present invention, an epoxy resin and a phenoxy resin are formed as an insulating adhesive layer on at least one surface of a conductive adhesive layer made of a conductive material and an epoxy resin and a phenoxy resin as a binder in the pressurizing direction. It is a multilayer connection member formed, Comprising: It is related with a thermosetting circuit connection member provided with the insulating contact bonding layer which has a melt viscosity equivalent to the said electroconductive contact bonding layer.
A second aspect of the present invention is a connection structure between electrode rows in which at least one of the opposed electrode rows protrudes, wherein the thermosetting circuit connecting member exists between the opposed electrodes and is insulative. The present invention relates to an electrode connection structure characterized in that the adhesive layer covers at least the periphery of the substrate side of the protruding electrode.
According to a third aspect of the present invention, at least one of the electrodes has a protruding electrode, and the insulating adhesive layer of the thermosetting circuit connecting member is disposed on the protruding electrode side between the electrode rows facing each other. The present invention relates to a method for connecting electrodes, characterized in that the melt viscosity at the time of connection between an insulating layer and an insulating adhesive layer is heated and pressed under a condition that the binder component is relatively lower than that of the insulating adhesive layer.
Furthermore, the fourth aspect of the present invention is the connection method in which the insulating adhesive layer of the thermosetting circuit connecting member is disposed on the protruding electrode side and heated and pressurized, and the heating and pressing step is divided into two or more stages. The present invention relates to a method for connecting electrodes, characterized in that a connection electrode energization inspection process and / or a repair process are performed as needed.

  According to the present invention, since the melt viscosity at the time of connection of the binder component is equivalent to that of the 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 connecting member of the present invention comprises an electrically conductive material and an insulating adhesive layer 2 containing an epoxy resin and a phenoxy resin on at least one side of the conductive adhesive layer 1 having conductivity in the pressurizing direction made of an epoxy resin and a phenoxy resin as a binder. Is a multilayer connection member formed. 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, when temporary bonding is performed 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 3, 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 4 as shown in FIGS. 3C to 3E, that is, a particle size substantially equal to the thickness of the binder 4. 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 4 is preferably as thin as possible within 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 4 as shown in FIG. 3 (f) to form a conductor by plating or the like, or may be in the form of conductive fibers such as wires 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. Alternatively, 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 3 with an insulating layer, or the combined use of conductive particles and insulating particles such as glass, ceramics, and plastics can be applied because the resolution is improved. In order to secure one or more particles, preferably as many particles as possible, on a minute electrode, small particle size particles of 15 μm or less are suitable, 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 material exhibiting curability by heat or light can be widely applied, and since heat resistance and moisture resistance after connection are excellent, application of a curable material is preferable. 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. Also, if a phenoxy resin that is similar in structure and compatible with the epoxy resin is used as the binder, the film formability is good, the dispersibility of the conductive material is improved, and the blending ratio with the epoxy resin is changed, so that melting at the time of connection is achieved. Convenient for changing the viscosity.

In the present invention, the melt viscosity at the time of connecting the binder component is equal to 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) and the insulating adhesive layer 2 (B) are equivalent under the temperature at the time of connection. FIG. 4 shows the binder component 4 and the insulating adhesive layer 2 with a lower melt viscosity of the binder component, but the melt viscosity is equal at the connection temperature. 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, it is preferable that the melt viscosity at the time of connection is such that the binder component is 500 poise or less.
When connecting the electrodes, the binder component 4 and the insulating adhesive layer 2 have the same composition, the melt viscosity is equal at a constant temperature, and heating is performed from the binder component side at the temperature at the time of connection. The melt viscosity at the time of connection of the binder component at a temperature of 5 ° C. can be equal to or less than that of the insulating adhesive layer. In this case, since the composition can be substantially the same, the connection member can be easily manufactured and the change in melt viscosity with respect to temperature can be equivalent, so that variations in connection temperature can be accommodated.

  In the contact process shown in FIG. 5 (a), the position of the conductive material 3 is maintained in a state where the conductive material 3 is relatively melt melted and embedded in the equivalent insulating adhesive layer 2 or partially captured. Is done. 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 14. In the embodiment in which the melt viscosity at the time of binder component connection is the same as that of the insulating adhesive layer, the insulating adhesive layer 2 can hold the conductive material 3 and connect the spaces between adjacent protruding electrodes without any bubbles. it can. 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 energization 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 between the planar electrode 14. 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 for producing the connection member of the present invention, for example, a method of laminating the conductive adhesive layer 1 and the insulating adhesive layer 2 or laminating and sequentially applying the layers can be employed.

  An electrode connection structure using the thermosetting circuit 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 13 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.

  According to the present invention, since the melt viscosity at the time of connecting the binder component is equivalent to that of the insulating adhesive layer, the conductive material 3 of the conductive adhesive layer 1 is insulated with a relatively equal melt viscosity when connecting the electrodes. The conductive material 3 is embedded in the conductive adhesive layer 2 or partially in contact with the conductive adhesive layer 2, and the position of the conductive material 3 is held on the protruding electrode 12. 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.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
Reference example 1
(1) Preparation of conductive adhesive layer The ratio of liquid epoxy resin (epoxy equivalent 185) containing phenoxy resin (high molecular weight epoxy resin) and microcapsule type latent curing agent is 30/70, and 30% by weight of ethyl acetate A solution was obtained. 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 Production of Connecting Member Conductive particles are removed from the conductive adhesive layer with the compounding ratio of (1) set to 40/60, and a sheet having a thickness of 15 μm is produced in the same manner as (1) above. 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) Connection Evaluation IC chip (silicon substrate, 2 × 12 mm, height 0.5 mm, 300 gold electrodes of 50 μmφ called 20 μm height called bumps are formed on the 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 connection 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 1 Ω or less and the insulation resistance was 10 ¹⁰ Ω or more. These were treated at 85 ° C., 85% RH, after 1000 hours. There was almost no change, and good long-term reliability was shown. 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 had different degrees of deformation of the particles depending on the variation in the distance between the electrodes facing each other, and some of the conductive particles bite into the bumps, and good connection was obtained for all the electrodes.

Comparative Example 1
1 was obtained, but a conventional single-layer conductive adhesive layer having a thickness of 20 μm was obtained. When evaluated in the same manner as in Reference 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. 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.

Reference example 2
Similarly, an insulating adhesive layer was formed on the other surface of the conductive adhesive layer of Reference Example 1 to obtain a multi-layer connection member having a three-layer structure shown in FIG. Moreover, it replaced with the glass plane electrode of the reference example 1, and was set as the 2 layer FPC circuit board which has a 18 micrometers high copper circuit on a polyimide film. The connection was made in the same manner as in Reference Example 1 to obtain a connection body corresponding to FIG. When evaluated in the same manner as in Reference 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.

Example 1, Reference Examples 3, 4 and Comparative Examples 2-3
Although it is the same as that of the reference example 1, the difference of the viscosity in 150 degreeC of both layers was changed by changing the compounding ratio of the phenoxy resin and liquid epoxy resin of an insulating contact bonding layer. The results are shown in Table 1 together with Reference Example 1 described above. In each of the examples and reference examples, the number of effective particles on the electrode was large and variation was relatively small, and good connection characteristics were exhibited as in Reference 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 Reference Example 1, but there are few effective particles and no effective particles are found on the electrode. Compared to 1, the maximum and minimum variations were large.

Comparative Examples 4-5
The FPC circuit boards of Reference Example 2 were connected as parallel electrodes (electrode width D = 50 μm, connection width L = 1500 μm, L / D = 30). Comparative Example 4 is a connection using the connection member of Reference 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 Reference 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.

Reference Examples 5-7
Although it is the same as that of the reference 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 of the reference examples with 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 exhibited as in Reference Example 1.

Reference Example 8
Although it is the same as that of the reference example 1, the bump of the IC chip connection surface was not 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 as in Reference Example 1, and it was unnecessary to form a protruding electrode on the chips, which was extremely economical.

Reference Example 9
Although it is the same as that of the connection member of the reference 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. Although this reference example is a connection between electrodes having a large height, there was no electrode displacement and a good connection characteristic was 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 reference 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.

Reference Examples 10-11
Although it is the same as that of the reference 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 (Reference 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 similarly tested without pressure (Reference 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 reference examples, since the adhesive was in a state where the curing reaction was insufficient, chip peeling 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 this reference example, the number of effective particles on the bump is increased and the outflow from the electrode is less than in Reference Example 1. Since the heating and pressurizing process is in two stages, it is considered that the retention of particles is further improved.

Reference Example 12
Although it is the same as that of the connection member of Reference Example 1, the conductive particles are carbonyl nickel having an uneven surface (average particle size 3 μm), the addition amount is 4 vol%, and the thickness of the conductive adhesive layer is 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. When evaluated in the same manner as in Reference Example 1, the tips of the conductive particles had digged 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 reference 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 13-15
Although it is the same as the connection member of the reference example 1, 1 volume% of the polystyrene-type particle | grains which are the cores of the electroconductive particle of the reference example 1 as an insulating particle, a conductive contact bonding layer (reference example 13), an insulating contact bonding layer ( Reference Example 14) and both layers (Reference Example 15) were mixed and dispersed. When evaluated in the same manner as in Reference 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 13, the insulating particles were dispersed between the conductive particles, which was effective in improving the resolution of the anisotropic conductivity of only the conductive adhesive layer. Reference Example 14 was effective in maintaining the insulating property of the insulating adhesive layer, and Reference Example 15 had the characteristics of both Reference Examples 13-14. The insulating particles of Reference Examples 13 and 15 were deformed and held between the electrodes in the same manner as the conductive particles.

Reference Example 16
Although it is the same as that of the connection member of Reference 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 Reference Example 1, but good connection characteristics were exhibited. In this reference example, the number of particles on the electrode significantly increased. The electrode connection can be conducted by softening the insulating layer and 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 Protruding electrode 13 Substrate 14 Planar electrode 15 Perimeter 16 Concave electrode 17 Top 18 Insulating layer

Claims (15)

A multi-layer connection member in which an epoxy resin and a phenoxy resin are formed as an insulating adhesive layer on at least one surface of a conductive adhesive layer having a conductivity in a pressurizing direction made of an epoxy resin and a phenoxy resin as a binder. A thermosetting circuit connecting member comprising an insulating adhesive layer having a melt viscosity equivalent to that of the conductive adhesive layer. The thermosetting circuit connecting member according to claim 1, wherein the melt viscosity at the time of connecting the binder component is 500 poise or less. The thermosetting circuit connecting member according to claim 1, wherein the binder component and the insulating adhesive layer contain a common material. The thermosetting circuit connecting member according to claim 1, wherein the binder component and the insulating adhesive layer have a difference in adhesiveness. The thermosetting circuit connecting member according to claim 1, wherein the binder component and / or the insulating adhesive layer contains insulating particles. The thermosetting circuit connecting member according to claim 1, wherein the conductive material is formed by forming an insulating coating on the surface of the conductive particles or the conductive particles. The thermosetting circuit connecting member according to claim 1, wherein the separator is in contact with the insulating adhesive layer. 2. The thermosetting circuit connecting member according to claim 1, wherein a ratio (L / D) of a major axis to a minor axis of the connecting electrode surface of the semiconductor chip is 20 or less. A connection structure between electrode rows in which at least one of the electrode rows facing each other protrudes, wherein the thermosetting circuit connecting member according to claim 1 exists between the electrodes facing each other, and an insulating adhesive layer is provided An electrode connection structure characterized by covering at least the substrate side periphery of the protruding electrode. The electrode connection structure according to claim 9, wherein the density of the conductive material is gradually reduced from the top of the protruding electrode to the substrate side. 2. The thermosetting circuit connecting member according to claim 1, wherein the insulating adhesive layer of the thermosetting circuit connection member according to claim 1 is disposed between the opposing electrode rows having at least one protruding electrode, so that the protruding electrode side is disposed, and the binder component and the insulating layer are insulated. An electrode connection method comprising heating and pressing under a condition in which a melt viscosity at the time of connection with the adhesive layer is relatively lower than that of an insulating adhesive layer. The electrode connection method according to claim 11, wherein a heat source is disposed on the insulating adhesive layer side and heated and pressurized. The connection which heat-presses by arrange | positioning so that the insulating adhesive layer of the thermosetting circuit connection member of Claim 1 may become the electrode side which protruded between the electrode rows which have the electrode which at least one protruded. In the method, the heating and pressurizing step is divided into two or more stages, and a connection electrode energization inspection step and / or a repair step are performed as necessary during the process. The electrode connection method according to claim 13, wherein an energization test is performed by increasing the cohesive force of the thermosetting circuit connection member to such an extent that the connection electrode can be held. The electrode connection method according to claim 14, wherein an energization inspection is performed while pressurizing the electrode connection portion.

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