JPH09312176A - Connecting member, and structure and method for connecting electrodes using this connecting member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connecting member, which can reduce the flow-out of the electrolyte from an electrode and which has excellent high resolution and excellent connecting reliability, by relatively setting the melt viscosity of a binder component at the time of adhesion equal to that of an insulating adhesive layer or less. SOLUTION: This connecting member is a multi-layer connecting member obtained by forming an insulating adhesive layer 2 in at least one surface of a conductive adhesive layer 1, which is formed of a conductive material and a binder and which has conductivity in the pressurizing direction. The insulating adhesive layer 2 can be formed in both surfaces of the conductive adhesive layer 1. Furthermore, the insulating adhesive layer 2 can be formed into the multi-layer structure so as to add an adhering function. The surface of these layer is provided with a separator 5, which can be peeled, at need so as to eliminate the unnecessary adhesiveness and so as to prevent the adhesion of dust. A binder component having melt viscosity at the time of connection at 500 poise or less is desirable. A bonder component having melt viscosity at the time of connection lower than that of the insulating adhesive layer 2 by 0.1-1000 poise is desirable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting member for bonding and fixing an electronic component such as a semiconductor chip and a circuit board, and electrically connecting the electrodes of the both, and a connecting structure and connection of electrodes using the connecting member. Regarding the method.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and thinning of electronic parts, circuits used therein have become higher in density and higher in definition. Since it is difficult to connect such electronic parts and fine electrodes with conventional solder and rubber connectors, recently, anisotropic conductive adhesives and film materials (hereinafter referred to as connecting members) with excellent resolution Is often used. The connecting member is made of an adhesive containing a conductive material such as conductive particles in a predetermined amount, and the connecting member is provided between the electronic component and the electrode or circuit to constitute a pressurizing or heating / pressurizing means. As a result, both electrodes are electrically connected to each other, and the electrodes formed adjacent to the electrodes are provided with an insulating property, 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 secure the insulating property between the adjacent electrodes by making the particle diameter of the conductive particles smaller than the insulating portion between the adjacent electrodes, and also to include the conductive particles. The amount is such that the particles do not come into contact with each other, and the particles are surely present on the electrode to obtain conductivity in the connecting portion.

[0003]

In the above-mentioned conventional method, when the particle size of the conductive particles is reduced, the particles are secondary-aggregated and connected due to the remarkable increase in the particle surface area, and the insulating property between the adjacent electrodes can be maintained. Disappear. In addition, when the content of the conductive particles is reduced, the number of conductive particles on the electrodes to be connected also decreases, so that the number of contact points is insufficient and conduction between the connecting electrodes cannot be obtained, so that long-term connection reliability is maintained. It was extremely difficult to increase the resolution of the connecting member. That is, due to the recent remarkable increase in resolution, that is, the miniaturization of the electrode area and the space between adjacent electrodes (space), the conductive particles on the electrodes flow out between the adjacent electrodes together with the adhesive due to the pressure at the time of connection or the heat and pressure. This has been an obstacle to increasing the resolution of the connecting member. At this time, if the viscosity of the adhesive is high in order to suppress the outflow of the adhesive, the contact between the electrodes and the conductive particles becomes insufficient, making it impossible to connect the electrodes facing each other. On the other hand, if the adhesive has a low viscosity, in addition to the outflow of the conductive particles, air bubbles are likely to be contained in the space portion, and the connection reliability, particularly the moisture resistance is deteriorated.

From the above, a connecting member having a multi-layered structure in which the conductive particle-containing layer and the insulating adhesive layer are separated is used, and the viscosity at the time of connecting the conductive particle-containing layer is relatively higher than that of the insulating adhesive layer. An attempt to hold the conductive particles on the electrode by making it difficult for the conductive particles to flow by the high cohesive force is also disclosed, for example, in JP-A-61-195179 and JP-A-4-36.
See, for example, Japanese Patent No. 6630. However, since the conductive particle-containing layer has a higher viscosity than the insulating adhesive layer at the time of connection, contact between the electrode and the conductive particles becomes insufficient,
Since the connection resistance value is high, the connection reliability is unsatisfactory.
Further, in order to reduce the connection resistance value, when the 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 high resolution. Can not. As a connection member that enables connection of such fine electrodes and circuits and is excellent in connection reliability, there is also a proposal of a connection member having a dense region of conductive particles in necessary portions in both directions. According to this, although it is possible to connect a dot-shaped fine electrode such as a semiconductor chip, there is a drawback that workability is inferior because accurate alignment of the dense region of conductive particles and the dot-shaped electrode is required.

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

[0006]

The first aspect of the present invention is to provide a multi-layer connection member in which an insulating adhesive layer is formed on at least one side of an adhesive layer made of a conductive material and a binder and having conductivity in the pressing direction. Further, the present invention relates to a connecting member for semiconductor chips, characterized in that the melt viscosity of the binder component at the time of connection is equal to or less than that of the insulating adhesive layer. A second aspect of the present invention is a connection structure between electrode rows in which at least one of the electrode rows facing each other protrudes, wherein the conductive material exists between the electrodes facing each other, and an insulating adhesive layer has a protruding electrode. Of at least the substrate side, and a structure of the electrode. According to a third aspect of the present invention, the insulating adhesive layer of the connecting member is arranged between the electrode rows having at least one protruding electrode so that the insulating adhesive layer of the connecting member is on the protruding electrode side, and the insulating component having a binder component and an insulating property is provided. The present invention relates to a method for connecting electrodes, wherein heating and pressurization are performed under the condition that the binder component has a relatively low melt viscosity at the time of connection with an adhesive layer as compared with an insulating adhesive layer. Furthermore, a fourth aspect of the present invention is a connection method in which the insulating adhesive layer is arranged so as to be on the protruding electrode side and heated and pressed, and the heating and pressing step is divided into two or more steps,
In the meantime, the present invention relates to a method of connecting electrodes, characterized in that an energization inspection step and / or a repair step of the connecting electrodes are performed as necessary.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of a connecting member for explaining an embodiment of the present invention. The connecting member of the present invention is a multi-layer connecting member in which an insulating adhesive layer 2 is formed on at least one surface of a conductive adhesive layer 1 made of a conductive material and a binder and having conductivity in the pressing direction. Insulating adhesive layer 2 as shown in FIG.
May be formed on both sides of the conductive adhesive layer 1. 1-2
In (1), although not shown, the insulating adhesive layer 2 may further have a multilayer structure to add a function such as adhesiveness. If necessary, a peelable separator 5 may be present on these surfaces as shown in FIG. 1 in order to prevent unnecessary adhesion and adhesion of dust and the like. Although not shown, the separator 5 can also be formed on the front and back sides. In the case of FIG. 1, since the separator 5 is in contact with the insulating adhesive layer 2, for example, when the substrate on one side is a planar electrode, the conductive adhesive layer in which the separator 5 does not exist on the planar electrode side with few irregularities is temporarily attached. Since 1 can be formed, connection is easy and workability is good, which is convenient. In these cases, a continuous tape shape is preferable because continuous automation of the connecting work step can be achieved.

FIG. 3 is a schematic sectional view for explaining the conductive adhesive layer 1 having conductivity in the pressing direction. Conductive adhesive layer 1
Is composed of a binder 4 containing a conductive material 3. Here, as the conductive material 4, the materials shown in FIGS. 3A to 3G can be applied. Among these, the conductive material 3 is shown in FIG.
As in (c) to (e), it is difficult for the conductive material 3 to flow at the time of connection to have a particle size that can exist in a single layer in the thickness direction of the binder 5, that is, a particle size approximately equal to the thickness of the binder 5. Moreover, the conductive material 3 is preferable because it can be easily held on the electrodes.
When the thickness of the conductive material 3 is almost equal to the thickness of the binder 4, the conductive material 3 can be electrically conductive with the electrode by a simple contact, and conductivity can be easily obtained.
The ratio of the conductive material 3 to the binder 4 is 0.1 to 20.
It is preferably about vol%, more preferably 1 to 15 vol% because anisotropic conductivity is easily obtained. Further, in order to easily obtain conductivity in the thickness direction and achieve high resolution, the thickness of the binder 5 is preferably as thin as possible in a film-forming range, and is preferably 20 μm or less, more preferably 10 μm or less. It is preferable that the conductive material 3 is formed of conductive particles as illustrated in FIGS. 3A to 3E, because the manufacturing thereof is relatively easy and easily available. Further, the conductive material 3 may be provided with a through hole in the binder 5 as shown in FIG. 3F to form a conductor by plating or the like, or may be a conductive fiber such as a wire as shown in FIG. 3G. .

As the conductive particles, Au, Ag, Pt, N
There are metal particles such as i, Cu, W, Sb, Sn, and solder, carbon, etc., and these conductive particles are used as a core material, or a core made of non-conductive polymer such as glass, ceramics, plastics, etc. The material may be coated with a conductive layer made of the above-mentioned material. Further conductive material 6
Insulating coated particles obtained by coating with an insulating layer, and combined use of conductive particles and insulating particles such as glass, ceramics, and plastics are also 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 diameter of 15 μm or less is suitable, and more preferably 7 μm or less and 1 μm or more. If the thickness is 1 μm or less, it is difficult to break through the insulating adhesive layer and make contact with the electrode. Also,
It is preferable that the conductive material 3 has a uniform particle size because the amount of outflow between the electrodes is small. Among these conductive particles, those in which a conductive layer is formed on a polymer core material such as plastic, or hot-melting metal such as solder have heat pressurization or deformability due to pressurization, and contact with the circuit at the time of connection. It is preferable because the area is increased and the reliability is improved. In particular, when a polymer is used as a nucleus, a melting point is not exhibited unlike solder, so that a softened state can be widely controlled by a connection temperature, and it is easy to cope with variations in electrode thickness and flatness. Also, for example, Ni or W
In the case of hard metal particles such as, or particles having a large number of protrusions on the surface, conductive particles pierce the electrode or wiring pattern, so low connection resistance is obtained even in the presence of an oxide film or a contaminated layer, and reliability is high. It is preferable because it improves.

For the binder 4 and the insulating adhesive layer 2, a thermoplastic material or a material curable by heat or light can be widely applied. It is preferable that these have high adhesiveness. Among these, since it is excellent in heat resistance and moisture resistance after connection,
The application of curable materials is preferred. Of these, epoxy adhesives are particularly preferable because they can be cured for a short time, have good workability in connection, and have excellent adhesiveness due to their molecular structure. Epoxy adhesives include, for example, high molecular weight epoxies, solid epoxies and liquid epoxies, urethanes and polyesters, acrylic rubbers, NBs.
Generally, an epoxy resin modified with R, silicone, nylon or the like is used as a main component, and a curing agent, a catalyst, a coupling agent, a filler and the like are added. It is preferable that 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 because the interfacial adhesion between both layers is improved. As the common material, the main material and the curing agent are more effective.

The present invention is characterized in that 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 of the binder component 4 and the insulating adhesive layer 2 during heating. In the present application, the binder component 4 (A) is the insulating adhesive layer 2 under the temperature at the time of connection.
It is relatively equal to or less than that of (B), and the difference in viscosity between (A) and (B) at this time is preferably about 0.1 to 1000 poise, more preferably 1 to 200 poise. It is a feature. 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 effectively obtain the contact between the electrode and the particle from the balance of the contact at the time of connection and the flow process. For similar reasons,
The melt viscosity at the time of connection is preferably 500 poise or less for the binder component, and the insulating adhesive layer has a viscosity of 100 poise or less.
It is more preferably 0 poise or less.

In the contact process shown in FIG. 5 (a), first, the conductive adhesive material 3 has an insulating adhesive layer 2 whose melt viscosity is relatively equal or higher.
The position of the conductive material 3 is retained in a state where the conductive material 3 is embedded or partially captured. Next, in the flow process of FIG. 5B, the conductive material 3 comes into contact with the protruding electrodes 12 due to the softening of the insulating adhesive layer, and the conductive material 3 becomes conductive with the planar electrode 13. In a preferred embodiment in which the melt viscosity at the time of connecting the binder component is lower than that of the insulating adhesive layer, the insulating adhesive layer 2 is capable of holding the conductive material 3 and bubbles the space between adjacent protruding electrodes. It can be connected without. In this case, in order to accelerate the softening of the insulating adhesive layer 2, the insulating adhesive layer of the connection member may be arranged so as to be on the protruding electrode side, and a heat source may be arranged on the insulating adhesive layer side to apply heat and pressure. preferable. At this time, the heating and pressurizing step may be divided into two or more steps, and an electrode connecting method including an electric current inspecting step and / or a repair step may be performed as necessary. By decomposing the heating / 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, so that good connection without bubbles can be achieved. In addition, repairability, which is a problem of curable adhesives, can be imparted.

The energization inspection step can be performed while increasing the cohesive force of the connection member or pressurizing the electrode connection portion to the extent that the connection electrode can be held. The through electrode inspection can be performed by, for example, taking out lead wires from both electrodes and measuring a connection resistance or an operation test. At this time, the visual inspection of the contact state between the conductive material 3 and the electrode can be performed together or independently. The repairability is to remove the adhesive in unnecessary portions, clean it with a solvent or the like, and reconnect it. Generally, a curable adhesive has been regarded as a problem since a net-like structure develops after completion of curing and becomes insoluble and infusible in heat, a solvent, etc., and cleaning is extremely difficult. In the first step of the heating and pressurizing step, for example, the conductive material 3 is in contact with the projecting electrode 12 and an electric conduction inspection of both electrodes is performed in a state where the conductive material 3 and the planar electrode 13 can conduct electricity. At this time, if there is a defective electrode connection portion, repair and reconnection are performed in this state. Since the adhesive is in an uncured state or in a state where the curing reaction is insufficient, it is easily peeled off, immersed in a solvent, and repair work is easy.

The method of measuring the melt viscosity is not particularly limited as long as it can relatively compare the binder component 4 and the insulating adhesive layer 2, but the same method is preferable, and for example, measurement at high temperature is possible. A general rotary viscometer can be used. At this time, for example, in the case of a thermosetting compound in which the reaction proceeds and the viscosity changes during measurement, the measured value in the model compound without the curing agent can be adopted. As a method of providing a difference in melt viscosity at the time of connecting the binder component 4 and the insulating adhesive layer 2, a combination of the molecular weight of the material and the intrinsic viscosity due to the entanglement of molecules, selection of a filler as a thickener, and curing It is common to control the difference in reaction rate in the system. As the method for producing the material of the connecting portion of the present invention, for example, the conductive adhesive layer 1
Then, a method of laminating the insulating adhesive layer 2 or laminating and sequentially applying the layers can be adopted.

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.
Is 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, at least one of the electrode rows facing each other has a connecting structure between the protruding electrode rows, and the conductive material 3 is present between the electrode rows 12-14 facing each other.
In addition, the conductive material exists in a state where the density of the conductive material is higher than that of the periphery 15 of the protruding electrode 12, and the electrode rows facing each other are connected to each other. Moreover, the insulating adhesive layer 2 covers at least the periphery 15 of the protruding electrode 12 of the protruding electrode 12. Here, the planar electrode 14
Indicates that there is no unevenness from the surface of the substrate 11, or even if there is, there is only a few μm or less. To exemplify these, the electrodes obtained by the additive method or the thin film method are typical.

FIG. 7 shows the case where the electrodes formed on the substrate are the protruding electrodes 12 and 12 '. That is, it is a structure in which both surfaces shown in FIG. 2 are connected via the connecting members having the insulating adhesive layers 2 and 2 ′. Insulating adhesive layers 2 and 2 '
Respectively cover the periphery of the protruding electrodes of the protruding electrodes 12 and 12 ′, and are in contact with the chip substrate surface 11 and the substrate surface 13. FIG. 8 shows a case where the electrodes formed on the substrate are the protruding electrode 12 and the concave electrode 16. Also in this case, the concave electrode 16 can be replaced with the flat electrode 14 shown in FIG. An example of the concave electrode 16 is, for example, an Al pad before forming a protruding electrode (bump) of a semiconductor chip or the like, and an unnecessary portion is covered with an insulating layer 18. The insulating layer 18 is made of silica, silicon nitride, polyimide, etc.
The thickness is generally 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, but both layers may be mixed, and they protrude as shown in FIG. The density of the conductive material 3 may be gradually decreased from the top 17 of the electrode 12 to the substrate 11 side. 6 to 8, as the chip substrate 11, silicon, gallium-arsenic, gallium-phosphorus, quartz, sapphire, garnet,
There are semiconductors such as ferrite. As the substrate 13, plastic films such as polyimide and polyester, composites such as glass fiber / epoxy, semiconductors such as silicon,
Examples include inorganic substances such as glass and ceramics. The protruding electrode 12 can include various circuits and terminals in addition to bumps. The various electrodes shown in FIGS.
They can be applied in any combination. Here, in the protruding electrode 12 of the chip substrate 11, the ratio (L / D) of the major axis and the minor axis of the connecting electrode surface of the semiconductor chip is preferably 20 or less, and more preferably 1 to 10. This is because the retention 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 the conductive particles on the electrode after connection, there is a very characteristic fact in the structure of the multilayer connecting member and the ratio of the major axis to the minor axis (L / D) of the electrode connecting surface. Is not fully clarified, but it is considered to be the influence of the directionality and heat transferability of the adhesive when it 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 side of the electrode 12 protruding, and the melt viscosity at the time of connecting the binder component and the insulating adhesive layer. Is heated and pressed under the condition that the binder component is relatively lower than that of the insulating adhesive layer.

[0019]

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 is relatively melted at the time of connecting the electrodes. The conductive material 3 is held on the protruding electrode 12 by being embedded in the insulating adhesive layer 2 having a viscosity equal to or higher than that of the insulating adhesive layer 2 or being in contact with the insulating adhesive layer 2 partially captured. Then, 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 the 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 a semiconductor chip or the like is small,
Since many conductive materials 3 are surely held on the minute protruding electrodes 12, connection reliability is high, and an expensive conductive material can be applied efficiently, which is resource saving.

According to the present invention, since the conductive material 3 is securely held on the protruding electrode 12 and can be conducted, the reliability of the conduction test is improved. The adhesive can be inspected for continuity in an uncured state or in an insufficiently cured state, so that repair work is easy. Since the insulating adhesive layer 2 is arranged so as to be on the side of the protruding electrode 12, the insulating property between adjacent electrodes and the resolution 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 more difficult to flow between the adjacent electrodes. Since the conductive material 3 of the conductive adhesive layer 1 is uniformly dispersed on the entire surface, it is not necessary to accurately align the conductive particles and the electrodes, and therefore workability is excellent. Depending on its purpose, the adhesive layer can be combined, for example, with an adhesive property suitable for the material of the electrode substrate, 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 by giving a difference in heat resistance, it is possible to preferentially separate from one substrate surface, and it is also possible to provide so-called repairability for reconnection. Alternatively, any combination suitable for the material of the electrode substrate can be used, and it is easy to obtain contact between the electrodes and the conductive particles, and the manufacturing method is also simple. Further, the adhesive layer can be made to stick out of the connecting portion to act as a sealing material, so that reinforcement and moistureproof effects can be obtained.

[0021]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Example 1 (1) Preparation of conductive adhesive layer The ratio of phenoxy resin (high molecular weight epoxy resin) and liquid epoxy resin containing a microcapsule type latent curing agent (epoxy equivalent 185) was 30/70, and ethyl acetate A 30% solution was obtained. Particle size 4 ± 0.2μ
m / polystyrene-based particles with a thickness of Ni / Au of 0.2 /
8% by volume of conductive particles having a metal coating of 0.02 μm were 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 was applied at 110 ° C. for 20 minutes.
After minute drying, a conductive adhesive layer having a thickness of 5 μm was obtained. The viscosity of the model formulation in which the curing agent of the adhesive layer was removed was measured with a digital viscometer HV-8 (manufactured by RESCA CORPORATION). 1
The viscosity at 50 ° C. was 80 poise.

(2) Formation of Insulating Adhesive Layer and Preparation of Connection Member The compounding ratio of (1) was set to 40/60, conductive particles were removed from the conductive adhesive layer, and a sheet having a thickness of 15 μm was formed as the above (1). It produced similarly. First, the conductive adhesive layer surface of (1) and (2)
The adhesive layer surface and the adhesive layer surface were laminated while being rolled between rubber rolls. As described above, a multi-layer connection member having a two-layer structure of FIG. One of the insulating adhesive layers measured as described above
The viscosity at 50 ° C. 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 IC chip for evaluation (silicon substrate, 2 × 12 mm, height 0.5 mm, 50 μm called bump on two long sides)
φ, 300 gold electrodes with a height of 20 μm are formed), and indium oxide thickness of 0.2 μm (IT
O, a flat electrode having a thin film circuit having a surface resistance of 20 Ω / □) was connected. 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 out to the periphery. The connection member was cut into 2.5 × 14 mm, which was slightly larger than the size of the IC chip, and the conductive adhesive layer was placed on the plane electrode side for temporary connection. Due to the smoothness of the substrate and the adhesiveness of the connecting member, the attachment was easy and the subsequent separation of the separator was easy. Then I
Align the bumps on the C chip with the planar electrodes, and
A connector was obtained by heating and pressurizing at 0 ° C., 30 kgf / mm 2 and 15 seconds. At this time, the heat source of the connecting device was arranged on the insulating adhesive layer side, and the conductive adhesive layer was arranged on the plane electrode side.

(4) Evaluation When the cross section of this connection body was polished and observed with a microscope, the connection structure was equivalent to that shown in FIG. In the space between the adjacent electrodes, particles were spherical without inclusion of air bubbles, but the particles were compressed and deformed on the electrodes and held in contact with the upper and lower electrodes. When evaluating the resistance between the electrodes facing each other and the insulation resistance between the adjacent electrodes, the connection resistance was 1Ω or less and the insulation resistance was 10 10
Ω or more, and these showed almost no change even after treatment at 85 ° C. and 85% RH for 1000 hours, and showed good long-term reliability.
On the electrode in this example (50 μmφ = 1962.5 μ
The effective average number of particles contributing to the connection of m2) was 20 (maximum 23 particles, minimum 18 particles, and so on). The effective particles contributing to the connection are those having a luster due to contact with the electrodes when the connection surface is observed from the glass side with a microscope (× 100). L / D is 50 μm
Since it is φ (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. There was no air bubble mixing between adjacent bumps, showing good long-term reliability. The conductive particles differ in the degree of deformation of the particles according to the variation in the relative distance between the electrodes, and some particles partially penetrate the bumps, and good connection was obtained in all the electrodes.

Comparative Example 1 The same procedure as in Example 1 was performed, but a single-layer conductive adhesive layer having a conventional structure and a thickness of 20 μm was obtained. When evaluated in the same manner as in Example 1, the maximum number of particles on the electrode (50 μmφ) is 13,
The number was 0 at the minimum, there were no effective particles on the electrode, and the maximum and minimum variations were large as compared with Example 1. Further, when the insulation resistance of the connected body was measured, a short circuit failure occurred. It is considered that the conductive particles flowed out from the electrodes at the time of connection, and the insulation between adjacent electrodes (space portion) could not be maintained.

Example 2 An insulating adhesive layer was similarly formed on the other surface of the conductive adhesive layer of Example 1 to obtain a multi-layered connecting member having a three-layer structure shown in FIG. Further, in place of the glass flat electrode of Example 1, a copper circuit having a height of 18 μm is provided on the polyimide film.
It was a layer FPC circuit board. 7 is connected in the same manner as in Example 1, and FIG.
I got a considerable connection. When evaluated in the same manner as in Example 1, excellent connection characteristics were shown. As for the number of effective particles on the electrodes, it was possible to secure 10 or more effective particles on all the electrodes, although the protruding electrodes were connected to each other, although the particles could easily flow out.

Examples 3 to 5 and Comparative Examples 2 to 3 As in Example 1, but the viscosity of both layers at 150 ° C. was changed by changing the compounding ratio of the phenoxy resin and the liquid epoxy resin in the insulating adhesive layer. The difference has changed. The results are shown in Table 1 together with Example 1 described above. In each of the examples, 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, effective particles were not seen on the electrodes, and connection was impossible. Comparative Example 3 is a conventionally known two-layer structure in which the structure of the connecting member is the reverse of that of Example 1, but the number of effective particles is small and some have no effective particles on the electrodes. There was a large variation between the maximum and the minimum in comparison with 1.

[0027]

[Table 1] ──────────────────────────────── Binder viscosity Viscosity difference Effective particle number on the electrode (poise) (Poise) (Pieces / 50 μmφ) ──────────────────────────────── Example 3 200 13 (11-15) ) Example 4 200 1 19 (17-22) Example 1 80 200 20 (18-23) Example 5 80 1000 16 (16-22) Comparative Example 2 80 10000 None Comparative Example 3 200-1206 (0) 14) ────────────────────────────────

Comparative Examples 4 to 5 The FPC circuit boards of 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 by the connecting 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 as compared with Example 1. Comparative Example 5 is a connection by the connecting member of Comparative Example 3, but the number of effective particles is 18 (14 to 24), which is improved as compared with Comparative Example 3. From these results, the optimum configuration of the connecting member is different between the case of connecting parallel electrodes such as a circuit board having a large L / D and the case of connecting dot electrodes having a small L / D such as a semiconductor chip electrode. I understood. The reason for this is unknown, but 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 to 8 Same as Example 1, but the bump shape on the IC chip connection surface was changed. The long diameter of the bump was oriented toward the center of the IC chip. Table 2 shows the results. In each of the examples of L / D = 1 to 10, the number of effective particles on the electrode was large, the variation was relatively small, and good connection characteristics were exhibited as in Example 1.

[0030]

[Table 2] ──────────────────────────────── Bump shape Ratio of major axis to minor axis Number of effective particles on the electrode (Μm) (L / D) (pieces / 50 μmφ) ──────────────────────────────── Example 6 50 × 50 1.41 24 (22 to 27) Example 7 20 × 100 5.0 162 (141 to 182) Example 8 20 × 200 10.0 245 (228 to 253) ─────────── ──────────────────────

Example 9 The same as Example 1, except that bumps on the IC chip connection surface were not formed. That is, it is a semiconductor chip of a concave electrode in which a pad is formed in a necessary portion of the Al wiring, and a portion other than the pad is covered with an insulating layer (SiO2 in this case) having a thickness of 1 .mu.m, which has the structure of FIG. In this case, the conductive adhesive layer side was temporarily connected to the semiconductor chip. In this example, similar to Example 1, good connection characteristics were exhibited, and it was not necessary to form protruding electrodes on the chips, which was extremely economical.

Example 10 The same as the connecting member of Example 2, except that the particle size of the conductive particles was 7 μm and the thickness of the conductive adhesive layer was 7 μm. The thickness of the insulating adhesive layer is 25 μm on one side and 50 μm on the other side.
Formed. The electrodes are QFP type IC leads (thickness 10
0 μm, pitch 300 μm, electrode width 350 μm, connection width 3000 μm, L / D = 8.6), which was connected to a terminal of copper thickness 35 μm on a glass epoxy substrate. This configuration is similar to that of FIG. 7, but has no substrate on the lead side (one side) of the IC. In this example, electrodes having a large height were connected to each other, but good connection characteristics were exhibited without any electrode displacement. 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. There were no bubbles mixed between adjacent electrodes, and good long-term reliability was shown.
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 electrodes could be 10 or more for all the electrodes.

Examples 11 to 12 Similar to Example 1, except that the glass substrate was changed to a substrate on which five IC chips could be mounted, and the heating and pressing process was performed in two stages. First, the connection resistance at each connection point was measured and inspected with a multimeter while applying pressure at 150 ° C. and 20 kgf / mm 2 for 2 seconds (Example 11). The same but the other one was removed from the connecting device after 3 seconds at 150 ° C., 20 kgf / mm 2. Since the cohesive force of the adhesive was improved by heating and pressurizing, each IC chip can be temporarily fixed to the glass side and was similarly inspected without pressing (Example 12). In both examples, one IC chip was abnormal. Therefore, when the abnormal chip was peeled off and a new chip was connected in the same way as above,
All were good. In both examples, the adhesive was in a state of insufficient curing reaction, so that chip peeling and subsequent cleaning using acetone were extremely simple, and the repair work was easy. After the energization inspection step and the repair step described above, connection was performed at 150 ° C., 20 kgf / mm 2, and 15 seconds, and both examples showed good connection characteristics.
The number of effective particles on the bumps could be ensured to be 19 or more in all electrodes. In this embodiment, the number of effective particles on the bumps is increased and the outflow from the electrodes is smaller than that in the first embodiment. Since the heating and pressurizing step is performed in two stages, it seems that the retention of particles is further improved.

Example 13 Similar to the connecting member of Example 1, except that the conductive particles were carbonyl nickel having an uneven surface (average particle size 3 μm), the addition amount was 4% by volume, and the thickness of the conductive adhesive layer was 5 μm. changed. In addition, the insulating adhesive layer is a carboxyl-modified SEBS
The ratio of the (styrene-ethylene-butylene-styrene block copolymer) and the liquid epoxy resin (epoxy equivalent 185) containing the microcapsule type latent curing agent is 20.
A sheet having a thickness of / 80 and a thickness of 15 μm was prepared in the same manner as above, and laminated on the surface of the conductive adhesive layer. Similarly measured viscosity at 150 ° C. was 100 poise. Therefore, the difference in viscosity between the conductive adhesive layer and the insulating adhesive layer is 2
0 poise. When evaluated in the same manner as in Example 1, the tips of the conductive particles bite into the electrode, and the number of effective particles on the electrode was 100 or more. The connection resistance, insulation resistance, and long-term reliability were all good. In this example, since the polymer components were changed between the conductive adhesive layer and the insulating adhesive layer, it was possible to cleanly peel off from the surface on the insulating adhesive layer side after bonding. This means that repair work is easy. The Tg (glass transition point) of the conductive adhesive layer and the insulating adhesive layer determined by a tensile method by TMA (thermo-mechanical analysis) was 125 ° C. for the former and 100 ° C. for the latter. This is effective for the peeling work because, when the peeling temperature is set to a high temperature in the repairing work, the peeling can be performed by utilizing the difference in heat resistance of the adhesive layer and the difference in cohesive force can be easily provided.

Examples 14 to 16 Similar to the connecting member of Example 1, except that 1% by volume of polystyrene-based particles, which is the core of the conductive particles of Example 1, were used as insulating particles, and the conductive adhesive layer (Example) was used. 14), the insulating adhesive layer (Example 15), and both layers (Example 16) 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 the insulating particles added was small, no influence was observed on the fluidity in each example. In Example 14, the insulating particles were dispersed between the conductive particles, and it was effective for improving the resolution of anisotropic conductivity of only the conductive adhesive layer. Example 15 is effective in maintaining the insulating property of the insulating adhesive layer, and Example 16 is the same as Example 14.
It had the characteristics of both .about.15. The insulating particles of Examples 14 and 16 were deformed and held between the electrodes similarly to the conductive particles.

Example 17 Similar to the connecting member of Example 1, the surface of the conductive particles was subjected to insulation coating treatment. That is, the surface of the conductive particles having an average particle diameter of 4 μm was coated with a nylon resin having a glass transition point of 127 ° C. to a thickness of about 0.2 μm, and the addition amount was increased to 15% by volume. The same evaluation as in Example 1 was performed, but good connection characteristics were shown. In this example, the number of particles on the electrode was significantly increased. The electrode connection can be conducted by softening the insulating layer and the binder due to the heat pressure at the time of connection, but the space in the adjacent electrode row has a small heat pressure and the surface of the conductive material remains covered with the insulating layer. The property was also good. The number of effective particles on the bumps could be 30 or more for all electrodes. With this structure, the density of the conductive material with respect to the binder can be made high.

[0037]

As described above in detail, according to the present invention, the melt viscosity of the binder component at the time of connection is equal to or less than that of the adhesive layer having a relatively insulating property. Few. Therefore, a connection member having high resolution and excellent connection reliability, an electrode connection structure using the same, and a connection method can be provided.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a connecting member of the present invention.

FIG. 2 is a schematic cross-sectional view showing another connecting member of the present invention.

FIG. 3 is a schematic sectional view showing a conductive adhesive layer in the present invention.

FIG. 4 is a diagram showing the melt viscosity of the adhesive layer in the present invention.

FIG. 5 is an explanatory diagram (a) showing a connection process in the present invention.
(B).

FIG. 6 is a schematic cross-sectional view showing an example of the electrode connection structure using the connection member of the present invention.

FIG. 7 is a schematic cross-sectional view showing an example of an electrode connection structure using the connection member of the present invention.

FIG. 8 is a schematic cross-sectional view showing an example of an electrode connection structure using the connection member of the present invention.

FIG. 9 is a schematic cross-sectional view showing an example of the electrode connection structure using the connection member of the present invention.

[Explanation of symbols]

 1 Conductive Adhesive Layer 2 Insulating Adhesive Layer 3 Conductive Material 4 Binder 5 Separator 11 Chip Substrate 12 Projecting Electrode 13 Substrate 14 Planar Electrode 15 Surrounding 16 Concave Electrode 17 Top 18 Insulating Layer

Front page continuation (72) Inventor Kyokuhisa Ota 1150 Gozamiya, Shimodate City, Ibaraki Prefecture Goshomiya Plant, Hitachi Chemical Co., Ltd. (72) Hiroshi Matsuoka 1150 Goshomiya, Shimodate City, Ibaraki Prefecture Hitachi Chemical Industry Co., Ltd.Goshonomiya Plant (72) Inventor Itsuo Watanabe 48 Taidai, Tsukuba, Ibaraki Prefecture Hitachi Chemical Co., Ltd.Tsukuba Development Co., Ltd. (72) Inventor Kenzo Takemura 48 Wadai, Tsukuba, Ibaraki Hitachi Chemical Co., Ltd. In the Research Laboratory (72) Inventor Naoyuki Shiozawa 48, Taidai, Tsukuba-shi, Ibaraki Hitachi Chemical Co., Ltd.Inside the Tsukuba Development Laboratory (72) Inventor Osamu Watanabe 48, Wadai, Tsukuba-shi, Ibaraki In the Hitachi Chemical Co., Ltd. 72) Inventor Kayoshi Kojima 48 Tsudai, Tsukuba-shi, Ibaraki Hitachi Chemical Co., Ltd. Tsukuba Development Laboratory

Claims (16)

[Claims] 1. A multi-layer connection member comprising an adhesive layer made of a conductive material and a binder and having conductivity in the pressing direction, and an insulating adhesive layer formed on at least one surface of the adhesive layer. A connecting member for a semiconductor chip, which has a viscosity equal to or lower than that of an insulating adhesive layer. 2. A melt viscosity at the time of connecting a binder component is 500.
The connecting member according to claim 1, which has a poise or less. 3. The connecting member according to claim 1, wherein the melt viscosity at the time of connecting the binder component is 0.1 to 1000 poises lower than that of the insulating adhesive layer. 4. The connecting member according to claim 1, wherein the binder component and the insulating adhesive layer contain a common material. 5. The connecting member according to claim 1, wherein the binder component and the insulating adhesive layer have a difference in adhesiveness. 6. The connecting member according to claim 1, wherein the binder component and / or the insulating adhesive layer contains insulating particles. 7. The conductive material comprises conductive particles or an insulating coating formed on the surfaces of the conductive particles.
The connecting member as described in the above. 8. The connecting member according to claim 1, wherein the separator is in contact with the insulating adhesive layer. 9. The connecting member according to claim 1, wherein the ratio (L / D) of the major axis and the minor axis of the connecting electrode surface of the semiconductor chip is 20 or less. 10. A connection structure between electrode rows in which at least one of the electrode rows facing each other is projected, and the conductive material according to claim 1 is present between the electrodes facing each other, and an insulating adhesive layer is provided. An electrode connection structure characterized by covering at least a substrate-side periphery of a protruding electrode. 11. The electrode connection structure according to claim 10, wherein the density of the conductive material is gradually reduced from the top of the protruding electrode to the substrate side. 12. The insulating adhesive layer of the connecting member according to claim 1 is arranged between the opposing electrode rows having protruding electrodes, at least one of which is arranged so as to be on the protruding electrode side. The method for connecting electrodes, wherein heating and pressurization are performed under the condition that the melt viscosity at the time of connection with the adhesive layer is relatively lower than that of the insulating adhesive layer having a binder component. 13. The method of connecting electrodes according to claim 12, wherein a heat source is arranged on the side of the insulating adhesive layer and heating and pressurization are performed. 14. A connection formed by arranging the insulating adhesive layer of the connecting member according to claim 1 so that the insulating adhesive layer is on the protruding electrode side, and heating and pressurizing the electrode between the opposing electrode rows having at least one protruding electrode. In the method, the heating and pressurizing step is divided into two or more steps, and an energization inspection step and / or a repair step of the connecting electrode are performed as necessary during the step, the electrode connecting method. 15. The method for connecting electrodes according to claim 14, wherein the current is inspected by increasing the cohesive force of the connection member to such an extent that the connection electrode can be held. 16. The method for connecting electrodes according to claim 14, wherein the current is inspected while applying pressure to the electrode connecting portion.