JP2007253629A - Manufacturing method of anisotropic conductive adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an anisotropic conductive adhesive sheet wherein conductive fine particles are regularly and densely arranged in the surface of a sheet (so that the distance between the adjacent conductive fine particles is 20 μm or below). <P>SOLUTION: Conductive fine particles are adsorbed on the adsorbing surface of an adsorbing device having such a surface to which suction pores smaller than the conductive fine particles to be arranged are formed in predetermined arrangement and a core film is subsequently pressed to the adsorbing surface from the adsorbed conductive fine particle side to take the conductive fine particles adsorbed on the adsorbing surface in the core film. Next, the adsorption of the conductive fine particles due to the adsorbing device is released to detach the core film from the adsorbing surface and adhesive layers are formed on both sides so as to hold the core film therebetween to manufacture the conductive adhesive sheet. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a conductive adhesive sheet that imparts conductivity only in the thickness direction of a sheet by conductive fine particles dispersedly arranged in the sheet surface, and a method for manufacturing the same.

2. Description of the Related Art Conventionally, a conductive adhesive sheet that imparts conductivity only in the thickness direction has been used when connecting a wiring of a liquid crystal display and a flexible substrate, or when mounting an integrated circuit component on a substrate at high density. An example of a conventional conductive adhesive sheet is shown in FIG. In this example, the conductive fine particles 4 are randomly arranged in the sheet 20 made of an adhesive layer. This sheet has the following problems.
In recent years, the dimensions of connected wiring patterns and land patterns have been increasingly miniaturized. When the size of the connected pattern is reduced, in the sheet in which conductive fine particles are randomly dispersed and arranged, the connected pattern is arranged at a position A where no conductive fine particles exist, as shown in FIG. The probability that As a result, the connected patterns may not be electrically connected.

  In order to solve this problem, it is effective to disperse smaller conductive fine particles in the sheet at a high density. However, when the size of the conductive fine particles is reduced, as shown in FIG. There is a problem that variations in the protruding height of the connection patterns P1, P2 from the surfaces of the substrates B1, B2 cannot be absorbed. When the density of the conductive particles 4 in the sheet 20 is increased, as shown in FIG. 13B, when the patterns P1 and P2 are arranged at a fine pitch, a short (short circuit) occurs between adjacent patterns. ) Is likely to occur. That is, in these methods, the connection reliability of a conductive adhesive sheet in which conductive fine particles are randomly dispersed and arranged is not improved.

On the other hand, Japanese Patent Application Laid-Open Nos. 5-67480 and 10-256701 describe that conductive fine particles are dispersed in a predetermined arrangement in a sheet.
In the method described in Japanese Patent Laid-Open No. 5-67480, the conductive fine particles are charged before being dispersed in the sheet (adhesive layer), and the repulsive force between the conductive fine particles is utilized to make the conductive fine particles in the sheet. Are uniformly dispersed. In addition, each position of the conductive fine particles and the support is charged with different charges, and after the conductive fine particles are arranged on the support in a predetermined arrangement, the conductive fine particles are transferred to the adhesive layer in a state in which this arrangement is maintained. It is described to do.
However, in this method, since the arrangement is maintained by the repulsive force between the charged conductive fine particles, it is impossible to bring the distance between the adjacent conductive fine particles within the sheet surface closer to 20 μm or less.

In JP-A-10-256701, a composition comprising a rubber material and conductive particles is formed into a sheet using conductive particles having magnetism, and a magnetic field is applied in the thickness direction of the sheet. It is described that the conductive particles are oriented to cure the rubber in this state.
However, this method has the following problems. Since it is difficult to concentrate the magnetic field in a very narrow region, the distance between adjacent conductive fine particles in the sheet surface cannot be brought close to 20 μm or less. In some cases, the conductive particles are arranged so as to overlap in the thickness direction of the rubber sheet. It is difficult to arrange the conductive particles regularly (while maintaining a predetermined interval between adjacent particles). The conductive particles that can be used are limited to magnetic materials.

  The present invention has been made paying attention to such problems of the prior art, and conductive adhesion imparting conductivity only in the thickness direction of the sheet by conductive fine particles dispersed and arranged in the sheet surface. It is an object of the present invention to provide a conductive adhesive sheet in which conductive fine particles are regularly and densely arranged in a sheet surface so that the distance between adjacent conductive fine particles is 20 μm or less. To do.

This invention is a manufacturing method of the electroconductive adhesive sheet which solved the said subject.
That is,
1. Adhesive layers are arranged on both sides of a core film arranged in the center in the thickness direction in an adhesive sheet that imparts conductivity only in the thickness direction of the sheet by conductive fine particles dispersed in the sheet surface. The core film and the adhesive layer are insulative, and the core film is formed of a resin having a softening temperature higher by 20 ° C. or more than the resin constituting the adhesive layer, and a part of the individual conductive fine particles or In the method for producing an electrically conductive adhesive sheet having anisotropy in which all are present in the core film and the conductive fine particles are arranged in a predetermined arrangement in the core film surface,
Using an adsorption device having an adsorption surface in which suction holes smaller than the conductive fine particles to be arranged are formed in a predetermined arrangement, after adsorbing the conductive fine particles on the adsorption surface of the adsorption device, the core film is adsorbed to the adsorbed conductive film. The conductive fine particles adsorbed on the adsorbing surface are pressed by pressing the adsorbing fine particle side toward the adsorbing surface or by applying a resin solution containing a core film component to the adsorbing surface with a predetermined thickness and drying the solvent. And then, after passing through the step of releasing the adsorption of the particles by the adsorption device and removing the core film from the adsorption surface, an adhesive layer is formed on both sides sandwiching the core film in the center Manufacturing method of adhesive sheet.
2. The conductive fine particles are made of copper, gold, silver, nickel, palladium, indium, tin, lead, zinc, bismuth, or an alloy of any of these metals, or fine particles made of carbon, or a metal coating on the surface. 2. The method for producing a conductive adhesive sheet according to 1, wherein the conductive adhesive sheet has fine particles.

According to the conductive adhesive sheet of the present invention, a plurality of through holes are formed in a predetermined arrangement in the core film surface, and conductive fine particles are arranged in the through holes. It is possible to set corresponding to the arrangement pitch of the pattern to be performed, the wiring width, and the like. In use, the arrangement of the conductive fine particles in the sheet surface is fixed by the core film.
Therefore, by setting the pitch and size of the through holes corresponding to the arrangement pitch and wiring width of the pattern to be connected, even when connecting patterns arranged at a fine pitch, short-circuits between adjacent patterns. Can be prevented from occurring. Further, it is possible to eliminate the fear that the pattern to be connected is disposed at a position where no conductive fine particles are present.

As a result, according to the conductive adhesive sheet of the present invention, a highly reliable connection can be performed even when the dimension of the pattern to be connected is small or when patterns arranged at a fine pitch are connected.
Further, according to the method for producing a conductive adhesive sheet of the present invention, the conductive fine particles are regularly and densely arranged in the sheet surface (so that the distance between adjacent conductive fine particles is 20 μm or less). It is possible to easily manufacture the conductive adhesive sheet.

  The core film used in the present invention needs to be formed from a resin having a softening temperature higher by 20 ° C. or more than the resin constituting the adhesive layer formed on both sides thereof. This is because the flow of resin occurs when the conductive adhesive sheet of the present invention is placed in the center and the components or substrates to be connected from above and below are heat-pressed, but the conductive fine particles arranged in advance are difficult to move. It is a device. That is, the adhesive layer needs to be fluidized before the core film is fluidized so that the adhesive layer moves following the unevenness of the connection bumps on the component or the substrate and no gap is generated. When the resin composing the core film is fluidized at the same time or before the adhesive layer is fluidized, it is difficult to connect the fine pitch because the conductive particles placed in a predetermined position move with the flow of the resin. It becomes. Therefore, the softening temperature of the core film is 20 ° C. or more, preferably 50 ° C. or more, more preferably 80 ° C. or more higher than the softening temperature of the adhesive resin forming the adhesive layer.

Here, the softening temperature of the core film and the adhesive layer means that the viscosity decreases greatly when the temperature of the resin forming the core film and the adhesive forming the adhesive layer is increased from room temperature (the slope of the viscosity curve). Means the first temperature that changes. This softening temperature can be examined by measuring the viscosity using a viscoelasticity measuring device such as a rheometer while increasing the temperature of the resin and the adhesive from room temperature at a constant rate.
As the resin forming the core film used in the present invention, polyimide resin, polyamide resin, polyamideimide resin, polysulfone resin, polyethersulfone resin, polyester resin, unsaturated polyester resin, polyallyl resin, polyolefin resin, polycarbonate resin, polystyrene A resin such as a resin, a polyphenylene ether resin, a thermoplastic resin containing these resins as a main component, or a thermosetting resin containing a thermosetting component of a type that is cured after being plasticized with heat is preferable.

The thickness of the core film greatly depends on the size of the conductive fine particles used. That is, in the conductive adhesive sheet of the present invention, it is necessary to bring conductive fine particles into contact with both patterns to be connected during use. There are no through-holes in the core film used in the present invention.
That is, the conductive particles arranged in a predetermined manner are in the holes not penetrating formed in the core film, or some or all of the individual conductive particles are taken into the core film. After only the layer is fluidized in accordance with the shape of the connection pattern and then curing is started by heat, the core film is softened by heat, and the portion of the thin core film around the conductive fine particles is fluidized. Therefore, it is necessary to set the thickness so that the core film, which is an insulator around the conductive fine particles, does not hinder connection.

The thickness of the core film is preferably not more than 3 times, more preferably not more than 2 times the average particle diameter of the conductive fine particles used in the conductive adhesive sheet. Further, the lower limit of the thickness is preferably 0.5 times or more, more preferably 0.75 times or more the average particle diameter of the conductive fine particles used in the conductive adhesive sheet. If the core film is thinner than this, the conductive fine particles contained in the holes or recesses will be removed together with the removal of the conductive fine particles adhering to places other than the holes or recesses formed in the core film.
Further, with reference to FIG. 1 (a-1), the thickness of the core film present at the bottom of the hole not penetrating is preferably 0. The thickness of the core film in the portion where no conductive fine particles are present. 5 times or less, more preferably 0.25 times or less. Further, the lower limit of the thickness of the core film present at the bottom of the non-penetrating hole is preferably 0.05 times or more, more preferably 0.1 times the thickness of the core film in the portion where no conductive fine particles are present. That's it. If it is thinner than this, when forming a recess not penetrating into the core film, when the core film is peeled from a mold having a protrusion corresponding to the recess, a location where physical strength cannot be maintained and the portion is broken. Or a portion that becomes a hole through which the concave portion passes is not preferable.

In the first method of the present invention, holes that do not penetrate are formed in the core film, and conductive fine particles are put only in these holes. Therefore, the conductive fine particles adsorbed at a place other than the holes must be blown away using compressed air or the like, or adhered and removed using an adhesive sheet or the like. In this step, when the hole depth is shallower than the particle diameter of the conductive fine particles used, the conductive fine particles entering the holes are removed together with unnecessary conductive fine particles. Therefore, the preferable depth of the hole is 0.5 times or more, more preferably 1 time or more of the average particle diameter of the conductive fine particles.
Therefore, the preferable thickness of the core film in the part where the holes are not opened is 0.7 times or more, more preferably 1.2 times or more the average particle diameter of the conductive fine particles used.

In the first method of the present invention, the size of the non-penetrating holes formed in the core film depends on the size of the conductive fine particles to be used, but preferably the average particle diameter of 1-1. 5 times. The arrangement of the holes depends on the arrangement pitch of the connection pattern and the wiring width, but it is preferable to arrange the holes at intervals of 0.3 to 1 times the arrangement pitch. Moreover, it is also possible to form a hole only in the pattern of the part to connect. However, in this case, it is necessary to align the connection pattern and the connection component.
The conductive fine particles used in the present invention preferably have an average particle size of 0.5 to 50 μm, more preferably 1 to 20 μm, and most preferably 2 to 10 μm. If the average particle size of the conductive fine particles is less than 0.5 μm, the variation in the height of the connection pattern may not be absorbed. On the other hand, when the size exceeds 50 μm, it is not suitable for connection of a fine pattern.

The shape of the conductive fine particles used in the present invention is not particularly required to be spherical, and polyhedral and spherical particles may have a large number of protrusions. However, a flat shape is not preferable because it is difficult to put in a hole or to be adsorbed by an adsorption device. Conductive fine particles that are easily crushed during compression and that are easy to deform are preferable because they can increase the contact area with the connection pattern and absorb variations in the height of the connection pattern.
The particle size distribution of the conductive fine particles used in the present invention is preferably such that the standard deviation is 50% or less of the average particle size. More preferably, the standard deviation is 20% or less of the average particle diameter, and most preferably 10% or less. If the particle size distribution of the conductive fine particles is widely distributed with a standard deviation exceeding 50% of the average particle size, the conductive fine particles having a small particle size may cause clogging of the through-holes, or may be present in places other than the holes. It becomes difficult to remove small conductive fine particles. Further, it becomes difficult to absorb the variation in the height of the connection pattern. This leads to a decrease in electrical connection reliability between connection patterns. Moreover, it is preferable that one conductive fine particle is contained in one hole, that is, one conductive fine particle exists in the thickness direction of the core film.

As a method for classifying the conductive fine particles, a usual method, for example, a centrifugal classifier such as cyclone or clacyclon, a gravity classifier, an inertia classifier, an airflow classifier, or a classifier by sieving can be used. In order to classify fine conductive fine particles having a particle diameter of 10 μm or less, first, coarse classification is performed using an airflow classifier or the like, and then a classification method is performed by sieving using a sieve in which through holes are precisely formed. Is preferred. When fine conductive fine particles having a particle diameter of 10 μm or less are classified by precision sieving, it is effective to use ultrasonic waves in a solvent such as alcohol that does not change the conductive fine particles.
As the adhesive forming the adhesive layer constituting the conductive adhesive sheet of the present invention, for example, a thermosetting adhesive, a thermoplastic adhesive, a pressure sensitive adhesive, or the like can be suitably used. In particular, it is preferable to use a type of adhesive containing a so-called latent curing agent in which a compound containing a curing agent is confined in a microcapsule and curing starts when the microcapsule is crushed by pressure or heat.

  Examples of the material for the adhesive layer include epoxy resins, polyimide resins, urea resins, amino resins, melamine resins, phenol resins, xylene resins, furan resins, isocyanate resins, benzocyclobutene resins, polyphenylene ethers. Examples thereof include a resin, a polysulfone resin, and a polyethersulfone resin. In particular, from the viewpoint of dimensional stability, heat resistance, etc., the resin constituting the adhesive used is an aromatic compound such as benzene, naphthalene, anthracene, pyrene, biphenyl, phenylene ether, cyclohexane, cyclohexene, bicyclooctane, bicyclo It is preferably composed of a compound having a skeleton of an aliphatic cyclic compound such as octene or adamantane in the molecular chain.

In addition, if an adhesive made of a resin soluble in a solvent is used, an adhesive layer can be obtained by applying the adhesive on a support in a state dissolved in a solvent and then drying. Preferably, the thickness of the adhesive layer after drying (solvent removal) is 1 μm to 50 μm, more preferably 5 μm to 20 μm. When the thickness is less than 1 μm, it is difficult to obtain adhesion strength after bonding. When the thickness of the adhesive layer exceeds 50 μm, the amount of the adhesive is too large and the electrical connection between the conductive fine particles and the connection pattern is hindered.
In the conductive adhesive sheet of the present invention, the first and second adhesive layers are formed on both sides of the core film, but these adhesive layers are different even if they have the same composition. It doesn't matter. The first and second adhesive layers may be a laminate of a plurality of adhesive layers having different functions.

When the conductive adhesive sheet of the present invention is exposed to an acidic aqueous solution, water, or the like in the production process, it is preferable to use an adhesive layer that does not undergo alteration or reaction in the aqueous processing solution. Further, by using an adhesive layer having tackiness or tackiness, the conductive adhesive sheet of the present invention can be temporarily fixed to an object to be connected.
Hereinafter, embodiments of the present invention will be described.
One embodiment of the conductive adhesive sheet of the present invention will be described with reference to FIG.
The conductive adhesive sheet shown in FIG. 1 (a-1) includes a core film 1 disposed in the center in the thickness direction, adhesive layers 2 and 3 disposed on both surfaces of the core film 1, and a spherical conductive property. It consists of fine particles 4. The core film 1 is made of a polysulfone thermosetting resin and has a thickness of 10 μm. The adhesive layers 2 and 3 are made of an epoxy thermosetting adhesive containing a latent hardener and have a thickness of 12 μm.

The conductive fine particles 4 are powders made of an alloy of copper and silver, and have an average particle size of 6 μm and a standard deviation of particle size distribution of 0.5 μm. The softening temperature of the polysulfone thermosetting resin used as the core film is 160 ° C., and the softening temperature of the epoxy thermosetting adhesive used as the adhesive layer is 60 ° C. A large number of holes 10 that do not penetrate in the thickness direction are regularly arranged in the film surface in the core film 1.
In this embodiment, as shown in FIG. 1 (b), holes 10 that do not pass through are located at the positions of lattice points (intersections between the vertical lines and horizontal lines of the lattice) and the center positions of the unit lattices in the film plane. Has been placed. The interval between adjacent lattice points along the vertical line is 15 μm, and the interval between adjacent lattice points along the horizontal line is 15 μm. The planar shape (cross-sectional shape along the film surface) of the hole 10 not penetrating is circular, and the diameter of this circle is 7.5 μm (1.25 times the average particle diameter of the conductive fine particles 4). In addition, one conductive fine particle 4 is disposed in every hole 10 of the core film 1.

The conductive adhesive sheet of FIG. 1A-2 is an example in which conductive fine particles arranged in a predetermined arrangement are embedded in the core film 1 in an embedded state. The thickness of the core film 1 is 4 μm, the thickness of the adhesive layers 2 and 3 is 10 μm, and the average particle size of the conductive fine particles is 6 μm.
These conductive adhesive sheets are pressed while being sandwiched between substrates to be connected during use. As a result, the adhesive layers 2 and 3 are deformed to start curing. Subsequently, the core film 1 is deformed with a time delay, and the conductive fine particles 4 are brought into contact with both patterns to be connected. At this time, the arrangement of the conductive fine particles 4 in the sheet surface is fixed by the core film 1. In this conductive adhesive sheet, as described above, the conductive fine particles 4 are regularly and densely arranged in the sheet surface (so that the distance between adjacent conductive fine particles is 20 μm or less). ing.

Therefore, according to the conductive adhesive sheet of this embodiment, even when the dimension of the pattern to be connected is small or when patterns arranged at a fine pitch are connected, a highly reliable connection can be made. In particular, by setting the pitch and size of the holes 10 in accordance with the arrangement pitch and wiring width of the pattern to be connected, the position where the conductive fine particles 4 do not exist (indicated by symbol A in FIG. 12). The fear of being placed in is eliminated.
According to the conductive adhesive sheet of this embodiment, since the conductive fine particles are regularly arranged, the conductive fine particles are extremely small (for example, a diameter of 2 μm or less, as in the case of being randomly arranged). Even if it is not, the probability that the pattern to be connected is arranged at a position where the conductive fine particles do not exist (indicated by symbol A in FIG. 12) is zero in principle. Therefore, in the conductive adhesive sheet of this embodiment, the conductive fine particles are made to have a certain size so that the connection pattern protrudes from the substrate surface more than the conductive adhesive sheet in which the conductive fine particles are randomly arranged. It becomes easy to absorb the variation in height.

FIG. 1C shows a conductive adhesive sheet in which the arrangement of the holes 10 in the plane of the core film 1 is different from the above. In this example, the holes 10 are arranged at the positions of lattice points in the film plane. In each of these holes 10, one conductive fine particle 4 is disposed.
Embodiment of the 1st method of manufacturing the electroconductive adhesive sheet of this invention is described using FIG. 2 and FIG.
A method for forming a mold having convex portions arranged in a predetermined arrangement on the surface will be described with reference to FIG. First, a resin pattern is formed on a substrate. FIG. 2B shows this state. As a method for forming a resin pattern on a substrate, there are a method using photolithography of a photosensitive resin, and a method of ablation processing in which the resin is melted or cut using a laser beam. A conductor film 12 is formed on the formed resin pattern by sputter deposition or electroless plating (FIG. 2 (c) shows this state), and then a metal 13 is grown by electrolytic plating, and the metal mold thus formed is formed. Is peeled from the substrate. FIG. 2 (e) shows this state.

Examples of the metal to be deposited by electrolytic plating used in the present invention include copper, nickel, chromium, or nickel plating in which polytetrafluoroethylene fine particles, silicon carbide fine particles, and boron nitride fine particles having a particle size of sub-μm are dispersed. it can. In some cases, a normal method such as a method of cleaning the resin adhering to the metal mold surface with a solvent or a method of removing in a high energy atmosphere such as plasma can be used. Further, the surface of a ceramic or resin plate or a cylindrical substrate can be patterned using laser light.
In order to form a pattern of 10 μm or less, an excimer laser is preferable. For pattern formation of about 10 to 20 μm, an excimer laser, a third harmonic of a YAG laser, or a copper vapor laser can be used.

As a method of forming a concave pattern on the surface of the core film, a method of pressing the core film formed in a sheet shape on the prepared mold while heating, and then peeling from the mold, There is a method in which a dissolved resin solution is applied in a predetermined thickness, and then the solvent is dried and peeled off from the mold (FIG. 3A).
When the core film is thin, it becomes difficult to handle by itself, so that the adhesive layer formed on the substrate before peeling from the mold can be adhered and reinforced from the adhesive side.
For example, the first adhesive is obtained by applying an adhesive solution (a liquid obtained by dissolving an adhesive in a solvent) on the support 5 made of a plastic film or the like to a predetermined thickness, and then removing the solvent by drying. Layer 2 is formed, and an adhesive layer is adhered to the surface of the core film that has no recess. As a method for applying the adhesive solution, a usual method such as a blade coating method, a spray coating method, a spin coating method, a roll coating method, or the like can be employed. This state is shown in FIG.

  Next, as shown in FIG. 3 (c), after spraying a powder made of a large number of conductive fine particles 4 from above the core film 1, the support 5, the first adhesive layer 2, the core film 1, The conductive sheet 4 is put into the hole 10 of the core film 1 by vibrating the entire sheet made of the above. The conductive fine particles 4a that do not enter the hole 10 and exist on the upper surface of the core film 1 are removed by pressing with a film with an adhesive or the like. By vibrating the entire sheet, the conductive fine particles 4 easily enter all the holes 10. Alternatively, the conductive fine particles 4 may be put into the holes 10 of the core film 1 by passing the entire sheet through the container a plurality of times in the conductive fine particles. In this way, as shown in FIG. 3D, the conductive particles 4 are put in each of the holes 10 one by one.

Next, after the adhesive solution is applied on the core film 1 at a predetermined thickness, the solvent is dried and removed, thereby forming the second adhesive layer 3 on the core film 1. Further, the cover film 6 is covered on the second adhesive layer 3. Thereby, as shown in FIG.3 (e), a conductive adhesive sheet is obtained in the state in which the support body 5 was joined to one surface, and the cover film 6 was joined to the other surface, respectively.
Instead of this, the cover film 6 on which the adhesive layer 3 is formed is heated by placing the adhesive layer 3 on the core film 1 with the adhesive layer 3 facing the core film 1 side, thereby heating the cover film 6 shown in FIG. It is good also as a state. However, the heating temperature in this case needs to be a temperature at which the adhesive forming the adhesive layer 3 is not cured.

In addition, a conductive adhesive sheet is used in the state which peeled the support body 5 and the cover film 6. FIG. Therefore, it is preferable to apply a silicone-based release agent to the surface of the support 5 on which the first adhesive layer 2 is formed and the surface of the cover film 6 on the second adhesive layer 3 side. .
As described above, according to the first method, by adopting a mold having fine convex portions arranged in a predetermined arrangement on the surface, it is easy to form a minute hole 10 having a diameter of 20 μm or less in the core film 1. Can be formed.

An embodiment of the second method for producing the conductive adhesive sheet of the present invention will be described with reference to FIGS.
First, the first adhesive layer 2 is formed on the support 5 by applying an adhesive solution with a predetermined thickness on the support 5 and then drying. FIG. 4A shows this state. A core film 1 having holes 10 as shown in FIG. 4B is bonded onto the first adhesive layer 2. FIG. 4C shows this state. This joining is performed by placing the core film 1 on the first adhesive layer 2 and heating. This heating temperature is set to a temperature at which the adhesive forming the adhesive layer 2 is not cured.
Next, the conductive fine particles 4 are filled into the through holes 10 of the core film 1 by the same method as the first method. Next, the second adhesive layer 3 is formed on the core film 1 and the cover film 6 is coated by the same method as the first method. Thereby, as shown in FIG.4 (e), a conductive adhesive sheet is obtained in the state by which the support body 5 was joined to one surface, and the cover film 6 was joined to the other surface, respectively.

In this second method, as shown in FIG. 4B, as a method of forming the core film 1 having the holes 10 not penetrating, the core film 1 is irradiated with laser light as shown in FIG. It is preferable to adopt the method of performing.
As an embodiment of the laser beam irradiation method, first, as shown in FIG. 5A, a metal mask K having an opening K1 corresponding to the hole 10 formed in the core film 1 is formed on the support 5. An adhesive layer is formed on the core film 1 made of a thermoplastic polyimide resin fixed on the adhesive layer, and an excimer laser is irradiated from above the mask K. Thereby, the part irradiated with the excimer laser of the core film 1 is removed, and the hole 10 is formed. FIG. 5B shows this state.

As the laser light used here, such as a carbon dioxide laser, a fundamental wave of a YAG laser, etc. having an oscillation wavelength in the infrared region, the third and fourth harmonics of a YAG laser, an excimer laser, a copper vapor laser, etc. Thus, the thing which can irradiate the light of an ultraviolet-ray or a vacuum ultraviolet-ray area | region is mentioned.
For example, by using the third and fourth harmonics of a YAG laser, a copper vapor laser, or an excimer laser, the minute hole 10 having a diameter of 20 μm or less can be easily formed. The cross-sectional shape of the hole may be tapered.
As described above, according to the second method, the fine hole 10 having a diameter of 20 μm or less can be easily formed in the core film 1 by employing the laser irradiation method.

In this embodiment, as a method for forming the first adhesive layer 2 on one surface of the core film 1 having the holes 10 not penetrating in the second method of the present invention, the first adhesive layer 2 is formed on the support 5. Although the method of joining the core film 1 having the non-through holes 10 on the formed first adhesive layer 2 is adopted, instead of this, for example, the core film 1 having the non-through holes 10 You may employ | adopt the method of apply | coating and drying an adhesive solution on top.
In this case, after forming the first adhesive layer on the core film, the core film side is turned up, and conductive fine particles are put in the holes, and then the second adhesive layer is formed on the core film. To do.
An embodiment of a third method for producing the conductive adhesive sheet of the present invention will be described with reference to FIG. After producing a jig 170 in which holes not penetrating with a predetermined arrangement and depth are formed in sheet-like or plate-like metal, ceramics, or resin, conductive fine particles are put into the formed holes (FIG. 6). (B)), pressing the core film 1 on the hole-opened surface of the jig or while heating, or applying a resin solution containing the core film component in a predetermined thickness and drying the solvent (FIG. 6 ( c)) After peeling the core film 1 from the jig to transfer the conductive fine particles arranged on the jig to the core film 1 (FIG. 6 (d)), both sides with the core film 1 sandwiched between the centers. Then, the adhesive layers 2 and 3 are formed (FIG. 6E).

As a method for producing the jig, there is a method of using a photosensitive resin as shown in FIG. 2 by photolithography, and a method of ablating by melting or bonding a resin as shown in FIG. 7 using a laser beam. is there. A conductor film is formed on the formed resin pattern by sputtering deposition or electroless plating, and then a metal is grown by electrolytic plating, and the formed metal is peeled from the substrate.
Examples of the metal to be deposited by electrolytic plating used in the present invention include copper, nickel, chromium, or nickel plating in which polytetrafluoroethylene fine particles, silicon carbide fine particles, and boron nitride fine particles having a particle size of sub-μm are dispersed. it can. In some cases, a normal method such as a method of cleaning a resin adhering to the surface of a metal jig with a solvent or a method of removing in a high energy atmosphere such as plasma can be used. Also, the surface of the ceramic or resin plate can be patterned using laser light. In order to form a pattern of 10 μm or less, an excimer laser is preferable.

For pattern formation of about 10 to 20 μm, an excimer laser or YAG laser third harmonic or fourth harmonic, or a copper vapor laser can be used.
If a silicon-based or fluorine-based release agent is coated on the surface where the non-penetrating holes arranged in the predetermined arrangement of the prepared jig are exposed, a jig that easily peels the core film can be produced.
Embodiment of the 4th method of manufacturing the electroconductive adhesive sheet of this invention is described using FIG.
FIG. 8 shows a particle adsorption device according to the present invention. FIG. 8A shows the parts of the apparatus. 1A is a perforated sheet-like component, and suction holes 10a smaller than the conductive fine particles to be arranged are formed in a predetermined arrangement. This becomes the adsorption surface of the conductive particles. 100 is a porous part, and a filter paper, a wire mesh, etc. are used. Reference numeral 200 denotes a suction funnel, and 201 denotes a suction surface thereof. 202 is a connection part to a pump. After assembling the suction device and sucking air from 202, the conductive particles 4 are dispersed on the adsorption surface, the conductive fine particles are adsorbed on the adsorption surface, and arranged in a predetermined arrangement. The adsorbed conductive fine particles are pressed from the upper side toward the adsorbing surface (FIG. 8B), or a resin solution containing a core film component is applied on the adsorbing surface with a predetermined thickness from the upper surface of the conductive particles. After the conductive fine particles adsorbed on the adsorption surface are taken into the core film by drying, the adsorption of particles by the adsorption device is released and the core film is removed from the adsorption surface (FIG. 8c). ), And an adhesive layer is formed on both sides of the core film in the center (FIG. 8D).

[Example 1]
(Preparation of conductive adhesive sheet)
In this example, a conductive adhesive sheet is produced by a method corresponding to the example of the first method of the present invention. This embodiment will be described with reference to FIG.
First, a polyethylene terephthalate (PET) film having a thickness of 25 μm was prepared, and the surface of this PET film was coated with polydimethylsiloxane as a release agent to a thickness of about 50 nm. A thermoplastic polyimide solution was applied to the surface of the PET film (support) 5 coated with a release agent using a blade coater. Next, the solvent was dried and removed from the coating film to form a film made of thermoplastic polyimide having a thickness of 10 μm on the PET film 5.

As the thermoplastic polyimide solution, a thermoplastic polyimide solution “UPA-N-221” manufactured by Ube Industries, Ltd. was used.
Next, cylindrical convex patterns having a diameter of 7.5 μm and a height of 8 μm are arranged on the surface in the same arrangement as the arrangement of the non-through holes 10 shown in FIG. Furthermore, a nickel plate-shaped mold 13 in which the same cylindrical convex pattern was regularly arranged at the center of the lattice was also produced.
A core film made of thermoplastic polyimide and having a thickness of 10 μm was placed on this mold, and a thermocompression treatment was performed at 180 ° C. and 1 MPa for 10 minutes using a hot press machine (FIG. 3A). After cooling, the core film was peeled from the mold to form a non-penetrating recess corresponding to the mold protrusion on one side of the core film.

Next, as shown in FIG. 3 (b), a PET film 5 having an adhesive layer (first adhesive layer) 2 made of an epoxy adhesive on one surface is used, and the adhesive layer 2 is used as a core. The film 1 was placed on the core film 1 and heated toward the surface without a concave portion, and joined by heating.
The PET film 6 in which the adhesive layer 3 made of an epoxy adhesive is formed on one surface was produced as follows. First, a polyethylene terephthalate (PET) film having a thickness of 25 μm was prepared, and the surface of this PET film was coated with polydimethylsiloxane as a release agent to a thickness of about 50 nm. An epoxy adhesive solution was applied to the surface of the PET film (cover film) 6 coated with a release agent using a blade coater. Next, a layer 3 made of an epoxy adhesive having a thickness of 10 μm was formed on the PET film 6 by drying and removing the solvent from the coating film.

The composition of the epoxy adhesive solution used was as follows: bisphenol A type liquid epoxy resin: 10 parts by weight, phenoxy resin: 10 parts by weight, latent hardener comprising microcapsule type imidazole derivative epoxy compound: 4.5 parts by weight, and Toluene / ethyl acetate mixture: 5 parts by weight.
Next, after spraying a powder made of a large number of conductive fine particles 4 on the core film 1, the conductive fine particles 4 are formed in all the holes 10 by applying vibration to the entire sheet using an ultrasonic vibration device. I put it in. Next, the adhesive film “SPV-363” manufactured by Nitto Denko Co., Ltd. is attached to the surface of the core film 1 using a roller and then peeled off, so that it does not enter the hole 10 and exists on the upper surface of the core film 1. The conductive fine particles 4a to be removed were removed.

Examples of the powder composed of the conductive fine particles 4 include Ag _x Cu _(1-x) (0.008 ≦ x ≦ 0.4) described in JP-A-6-223633, and silver on the particle surface. Concentration is higher than 2.2 times the average silver concentration, and is composed of spherical conductive particles having a region where the silver concentration increases toward the particle surface near the surface, the average particle size is 6 μm, and the standard deviation of the particle size distribution A powder having a thickness of 0.5 μm was used.
Next, as shown in FIG. 3 (d), a PET film 6 having an adhesive layer (second adhesive layer) 3 made of an epoxy adhesive on one surface is used, and the adhesive layer 3 is used as a core. The film 1 was placed on the core film 1 and heated by heating toward the film 1 side.

As described above, the adhesive layers 2 and 3 made of an epoxy adhesive are arranged on both surfaces of the core film 1 made of a thermoplastic polyimide resin, and the core film 1 has circular holes 10 having a diameter of 7.5 μm, A conductive adhesive sheet which is regularly formed at a pitch of 15 μm (lattice spacing) in the arrangement shown in FIG. 1B, and each conductive fine particle 4 made of copper-silver alloy is arranged in each hole 10. was gotten. PET films 5 and 6 are bonded to both surfaces of the conductive adhesive sheet.
The softening temperature of the thermoplastic polyimide and epoxy adhesive forming the core film was measured using a rotary “rheometer” which is a viscoelasticity measuring device manufactured by Rheometrics Scientific F.E. The measurement conditions were a rotation speed: 10 rad / sec, a temperature rise start temperature: room temperature, a temperature rise speed: 10 ° C./min, and the first temperature at which the slope of the viscosity curve changed was determined as the softening temperature. As a result, the softening temperature of the epoxy adhesive was about 60 ° C., and the softening temperature of the thermoplastic polyimide was 170 ° C.

(Production of mold)
Zinc displacement plating was performed on the surface of aluminum, and a copper layer having a thickness of 3 μm was formed thereon using a copper pyrophosphate plating bath. Further, the copper surface was blackened to produce a conductive substrate having a low reflectance.
A photosensitive resin layer having a thickness of 10 μm was formed on the conductive substrate, and a resin pattern was obtained using photolithography through a glass chromium mask corresponding to the hole arrangement pattern shown in FIG.
The photosensitive resin used was an unsaturated polyester prepolymer having a number average molecular weight of 2000: 100 parts by weight, tetraethylene glycol dimethacrylate: 10.7 parts by weight, diethylene glycol dimethacrylate: 4.3 parts by weight, pentaerythritol tris Methacrylate: 15 parts by weight, phosphoric acid (monomethacryloyloxyethyl): 3.6 parts by weight, 2,2-dimethoxy-2-phenylacetophenone: 2 parts by weight, 2,6-di-tert-butyl-4-methylphenol : 0.04 parts by weight, and “OPLAS Yellow 140” manufactured by Orient Chemical Co., Ltd .: 0.11 parts by weight were added and mixed by stirring.

The unsaturated polyester prepolymer having a number average molecular weight of 2,000 was obtained by dehydration polycondensation reaction by adjusting the charging ratio of adipic acid, isophthalic acid, itaconic acid, fumaric acid and diethylene glycol. The number average molecular weight was measured using a gel permeation chromatography apparatus manufactured by Shimadzu Corporation and calibrated with a polystyrene standard product.
Next, as an exposure mask M, a circular chrome pattern having a diameter of 7.5 μm has the same arrangement as the arrangement of the through holes 10 shown in FIG. A glass photomask regularly arranged in the center was prepared. This exposure mask M was placed on the photosensitive resin layer 11, and the light from the ultrahigh pressure mercury lamp was irradiated on the exposure mask M. This irradiation light is a parallel light beam obtained by collimating the light from the light source by the optical system. FIG. 2A shows this state. However, in this figure, a PET cover film having a thickness of 10 μm is omitted.

Next, the PET cover film was peeled off and developed. As a result, the portion of the photosensitive resin layer 11 that was not exposed to light was removed, and the core film 1 having a large number of holes 10 was formed on the conductive substrate, as shown in FIG.
Next, the substrate surface on which the resin pattern was formed was subjected to a palladium catalyst application treatment, followed by electroless nickel plating to form a nickel layer having a thickness of several μm. Furthermore, electrolytic nickel plating was performed in a nickel sulfamate plating bath to form a nickel layer having a thickness of 70 μm. FIG. 2 (d) shows this state.
Thereafter, the formed nickel layer was peeled from the substrate to obtain a nickel mold in which cylindrical convex portions having a diameter of 7.5 μm and a height of 10 μm were regularly arranged on the surface. The surface of the obtained mold was treated with a silicone mold release agent (manufactured by Shin-Etsu Chemical Co., Ltd., SEPA-COAT SP).

(Performance evaluation)
FIG. 9A is a plan view showing a part of the test substrate, and FIG. 9B is a cross-sectional view taken along the line aa of FIG. 9A. The test substrate 30 has 200 wirings 32 on an insulating substrate 31, and the wirings 32 have a thickness of 15 μm and are exposed on the insulating substrate 31 in a convex shape. The width of the wiring 32 is 15 μm, and the arrangement pitch p is 30 μm.
First, the PET films 5 and 6 were peeled off from both surfaces of the conductive adhesive sheet obtained by the above-described method, and all the wiring 32 portions of the test substrate 30 and a plan view of the pattern are shown in FIG. A glass substrate is sandwiched between one convex linear pattern 22 and a substrate D having a convex circular pattern 21 and an inspection terminal 26, and heated to 230 ° C. under a pressure of 50 MPa for 5 minutes. Retained.
All the patterns of the substrate D are made using copper plating, the width of the linear pattern 22 is 15 μm, and the thickness is 15 μm. The diameter of the circular pattern arranged on both sides of the linear pattern 22 is 15 μm, and the height is 15 μm. They are arranged with a pitch of 30 μm. A thin chromium layer is formed between the glass substrate and the copper plating film for the purpose of improving adhesion. The circular pattern 21 is a dummy pattern for ensuring stability during connection evaluation. At this time, the wiring 32 of the test substrate 30 and the linear pattern of the substrate D were arranged so as to be orthogonal to each other. As a result, the wiring 32 portion of the test substrate 30 and the substrate D were bonded by the conductive adhesive sheet.

In FIG. 10, the wiring 32 portion of the test substrate 30 and the substrate D on which a convex conductor pattern is formed on the glass substrate whose plan view is shown in FIG. It is sectional drawing which shows the state. This sectional view corresponds to the sectional view taken along the line bb of FIG. At the time of bonding, the core film 1 of the conductive adhesive sheet and the adhesive layers 2 and 3 on both sides thereof are deformed, and these are collectively shown by reference numeral 23 in FIG.
A connection confirmation test using the conductive adhesive sheet of Example 1 was performed using the two test pieces thus obtained. That is, for each test piece, the resistance between the 200 test pads 35 and the test pads on the substrate D was measured. As a result, it was found that none of the total of 400 connection points of the two test pieces is not electrically connected to the copper substrate D.
Next, the PET films 5 and 6 are peeled off from both surfaces of the conductive adhesive sheet obtained by the above method, and all the wiring 32 portions of the test substrate 30 and the glass whose cross-sectional structure is shown in FIG. The plate was sandwiched between the plates E, heated to 230 ° C. under a pressure of 50 MPa, and held for 5 minutes. On the glass substrate E, the surface is uneven in the same pattern as the pattern shown in FIG. That is, ablation processing was performed using an excimer laser so that the hatched portion in FIG. The height of the convex portion was 15 μm. As a result, the wiring 32 portion of the test substrate 30 and the glass substrate were bonded by the conductive adhesive sheet. Similar to the connection confirmation test, both substrates were arranged so that the wiring 32 of the inspection substrate and the linear pattern on the glass substrate E were orthogonal.

Using the two test pieces thus obtained, the insulation resistance between adjacent test pads 35 was measured. As a result, regarding the total of 398 test pads 35 of the two test pieces, all the insulation resistances were 10 ¹² Ω or more. As a result, it was found that no short circuit occurred at all the adjacent connection points for all the connection points of the total 398 sets of the two test pieces.
From these test results, with the conductive adhesive sheet of this example, as shown in FIG. 9, the wiring 32 and the substrate D of the test substrate 30 are connected by the conductive fine particles 4 of the conductive adhesive sheet and are adjacent to each other. It can be seen that the wirings 32 are not connected by the conductive fine particles 4.

[Example 2]
(Preparation of conductive adhesive sheet)
A conductive adhesive sheet having anisotropic conductivity was produced by the same method as in Example 1 except that the resin forming the core film was a polysulfone resin composition in which polysulfone and cyanate ester were dissolved in tetrahydrofuran.
The polysulfone-based thermosetting resin solution used was composed of 80 parts by weight of a polysulfone resin (Amoco Polymer, Udel P-1700), 20 parts by weight of a cyanate ester resin (Ciba-Geigy, B-30), and 400 parts by weight of THF. Obtained by stirring and mixing.
The softening temperature of the polysulfone-based thermosetting resin was determined by the same method as in Example 1. As a result, the softening temperature of the polysulfone-based thermosetting resin was 160 ° C.

(Performance evaluation)
Using the conductive adhesive sheet produced in Example 2 and the same test substrate 30, substrate D, and glass substrate E as in Example 1, two test pieces were formed in the same manner as in Example 1. A connection confirmation test and a short confirmation test were performed in the same manner as in Example 1.
As a result, in the connection confirmation test, it was confirmed that none of the total 400 connection locations of the two test pieces was not electrically connected to the substrate D.
Further, in the short check test, all the insulation resistances were 10 ¹² Ω or more for a total of 400 test pads 35 of two test pieces. As a result, it was confirmed that no short circuit occurred between all the adjacent connection wirings 32 at all the connection points of the total 398 sets of the two test pieces.

[Example 3]
(Preparation of conductive adhesive sheet)
In this example, a conductive adhesive sheet is produced by a method corresponding to the example of the second method of the present invention. This embodiment will be described with reference to FIG.
First, a polyethylene terephthalate (PET) film having a thickness of 25 μm was prepared, and the surface of this PET film was coated with polydimethylsiloxane as a release agent to a thickness of about 50 nm. An epoxy adhesive solution was applied to the surface of the PET film coated with the release agent using a blade coater. Next, by removing the solvent from the coating film by drying, an adhesive layer made of an epoxy adhesive having a thickness of 12 μm was formed on the PET film. Two sheets comprising this PET film and an adhesive layer were prepared.
The composition of the epoxy adhesive solution used was as follows: bisphenol A type liquid epoxy resin: 10 parts by weight, phenoxy resin: 10 parts by weight, latent hardener comprising microcapsule type imidazole derivative epoxy compound: 4.5 parts by weight, and Toluene / ethyl acetate mixture: 5 parts by weight.

On the other hand, the surface of the same PET film as described above was coated with polydimethylsiloxane as a release agent in a film thickness of about 50 nm. A thermoplastic polyimide resin solution (“UPA-N-111C” manufactured by Ube Industries, Ltd.) was applied to the surface of the PET film coated with the release agent using a blade coater. Next, by removing the solvent from the coating film by drying, a core film 1 made of a thermoplastic polyimide resin is formed on the PET film (support) with a thickness of 10 μm. Was adhered from the core film side, and then the PET film was peeled off.
Next, a nickel metal mask K having an opening K1 designed so as to form a non-through hole 10 formed in the core film 1 is prepared, and the metal mask K is disposed above the core film 1, Excimer laser was irradiated from above the metal mask K. FIG. 5A shows this state. In the metal mask K, circular holes having a diameter of 7.5 μm are regularly formed at a pitch of 15 μm (lattice interval) with the same arrangement as the arrangement of the through holes shown in FIG.

Excimer laser irradiation was performed using an excimer laser processing apparatus including an excimer laser “INDEX800” manufactured by LUMONICS and a transport system “SIL300H” manufactured by Sumitomo Heavy Industries, Ltd. The wavelength of the laser was 248 nm (krypton fluoride gas), the size of the laser beam was 8 mm × 25 mm, and the oscillation frequency was 200 Hz.
As a result, the portion of the core film 1 irradiated with the excimer laser (the lower portion of the opening K1) was removed, and the non-through hole 10 was formed at a predetermined position of the core film 1. In the core film 1, circular non-through holes 10 having a diameter of 7.5 μm and a depth of 8 μm are regularly arranged at a pitch of 15 μm (lattice point spacing) in the arrangement shown in FIG. . FIG. 5B (same as FIG. 4C) shows this state.

After the powder composed of a large number of conductive fine particles 4 is dispersed on the core film 1, the conductive fine particles 4 are put in all the through holes 10 by applying vibration to the entire sheet using an ultrasonic vibration device. It was. This state is shown in FIG. Next, the adhesive film “SPV-363” manufactured by Nitto Denko Corporation is attached to the surface of the core film 1 using a roller, and then peeled off, so that it does not enter the through-hole 10 and the upper surface of the core film 1 The existing conductive fine particles were removed.
Examples of the powder composed of the conductive fine particles 4 include Ag _x Cu _(1-x) (0.008 ≦ x ≦ 0.4) described in JP-A-6-223633, and silver on the particle surface. Concentration is higher than 2.2 times the average silver concentration, and is composed of spherical conductive particles having a region where the silver concentration increases toward the particle surface near the surface, the average particle size is 6 μm, and the standard deviation of the particle size distribution A powder having a diameter of 0.6 μm was used.

Next, as shown in FIG. 4 (e), an adhesive layer (second adhesive layer) prepared in advance by the above-mentioned method and having an adhesive layer made of an epoxy adhesive formed on a PET film is formed. ) It was placed on the core film 1 with the 3 side facing down and joined by heating.
Thereby, the adhesive layers 2 and 3 made of 12 μm thick epoxy adhesive are arranged on both surfaces of the core film 1 made of polyimide resin and having a thickness of 7.5 μm. The through-holes 10 are regularly formed at a pitch of 15 μm (lattice point spacing) in the arrangement shown in FIG. 1B, and one conductive fine particle 4 made of copper-silver alloy is arranged in each hole 10. A conductive adhesive sheet was obtained. PET films 5 and 6 are bonded to both surfaces of the conductive adhesive sheet.

(Performance evaluation)
Using the conductive adhesive sheet produced in Example 3 and the same test substrate 30, substrate D, and glass substrate as in Example 1, two test pieces were produced in the same manner as in Example 1. Then, a connection confirmation test and a short confirmation test were performed in the same manner as in Example 1.
As a result, in the connection confirmation test, it was confirmed that none of the total 400 connection locations of the two test pieces was not electrically connected to the substrate D.
In the short check test, all the insulation resistances were 10 ¹² Ω or more for a total of 398 sets of wirings 32 of two test pieces. As a result, it was confirmed that no short circuit occurred between all the adjacent wirings 32 at all the connection points of the total 398 sets of the two test pieces.

[Example 4]
(Production of conductive fine particle array jig)
The conductive fine particle array jig shown in FIG. 7B was produced by the following method.
First, as shown in FIG. 2 (b), a negative photosensitive resin layer 8 is formed on a conductive substrate 13, and a light transmission portion corresponding to a hole into which conductive fine particles enter is provided on the negative photosensitive resin layer 8. A photomask M is arranged, and light is irradiated from above the photomask M. Next, a predetermined development process is performed to remove a portion of the photosensitive resin layer 8 that was not exposed to light. Thereby, a square columnar resin pattern is formed on the conductive substrate.
FIG. 2 (c) shows this state.
Next, a metal is deposited by electrolytic plating on the portion of the conductive substrate where the resin pattern does not exist, and the metal is further grown beyond the height of the cylindrical resin pattern. As a result, a metal 13 having a recess corresponding to the cylindrical resin pattern is grown. FIG. 2 (d) shows this state. Next, the metal body 13 is peeled from the conductive substrate 7. Further, since the columnar resin pattern cured by exposure to light may remain on the surface of the metal body 13, the remaining photosensitive resin layer is removed by a reactive ion etching method in an oxygen atmosphere. Thereby, as shown in FIG. 7B, a conductive fine particle arrangement jig 170 in which the metal body 13 having the holes 171 that do not penetrate is formed.

For the production of the conductive fine particle array jig, one having the same composition as that of the photosensitive resin used for mold production in Example 1 was used.
Before forming the metal body 13 by the electrolytic plating method, reactive ion etching was performed as a pretreatment for plating. Moreover, the back surface of the aluminum substrate 7 was covered with an adhesive film. Using a nickel sulfamate plating bath, a metal body 13 made of a nickel plating film slightly containing boron was obtained. The thickness of the metal body 13 was 100 μm.
The surface of the conductive fine particle arranging jig where the concave portion exists was thinly coated with a spray type silicone release agent and then fixed by heat treatment.

(Preparation of conductive adhesive sheet)
In this example, a conductive adhesive sheet is produced by a method corresponding to the example of the third method of the present invention. This embodiment will be described with reference to FIG.
First, the sheet | seat which consists of PET film (support body) 5, the adhesive bond layer 2, and PET film (support body) 6 and the adhesive bond layer 3 was produced with the following method. A polyethylene terephthalate (PET) film having a thickness of 25 μm was prepared, and the surface of this PET film was coated with polydimethylsiloxane as a release agent to a thickness of about 50 nm. An epoxy adhesive solution was applied to the surface of the PET film coated with the release agent using a blade coater. Next, the solvent was dried and removed from the coating film, thereby forming an adhesive layer made of an epoxy adhesive having a thickness of 30 μm on the PET film. Two sheets of the support coated with an adhesive layer were formed.

The composition of the epoxy adhesive solution used was as follows: bisphenol A type liquid epoxy resin: 10 parts by weight, phenoxy resin: 10 parts by weight, latent hardener comprising microcapsule type imidazole derivative epoxy compound: 4.5 parts by weight, and Toluene / ethyl acetate mixture: 5 parts by weight.
A composition having the same composition as the polysulfone-based thermosetting resin composition used in Example 2 was prepared and used for forming the core film.
After the conductive fine particles 4 are put into the non-through holes of the conductive fine particle arranging jig described above, and the polysulfone resin composition is applied to the surface where the conductive fine particles are arranged, the solvent tetrahydrofuran is removed by drying, and the thickness is 5 μm. A coating was obtained.

Next, the sheet | seat which coat | covered the adhesive bond layer on the already formed support body was adhere | attached by heat-compressing the surface of an adhesive bond layer and the polysulfone resin film which embedded the electroconductive fine particles. Thereafter, the sheet on which the polysulfone resin layer and the adhesive layer were bonded was peeled from the conductive fine particle array jig.
Further, another adhesive sheet was placed on the core film in which the conductive fine particles were embedded, and the adhesive layer was placed on the core film.
As the conductive fine particles 4, the same fine particles as in Example 1 were used.
The conductive fine particles 4 are allowed to enter all the non-through holes 10 by moving the conductive fine particle array jig by applying ultrasonic vibration. Moreover, the electroconductive fine particles adhering to surfaces other than the non-through-hole 10 of a jig were removed using the adhesive film "SPV-363" by Nitto Denko Corporation. The adhesive layers 2 and 3 were pressed against the surface on which the conductive fine particles were arranged while being heated to 50 ° C.
As described above, a conductive adhesive sheet was obtained in which an adhesive layer composed of two layers of epoxy adhesive was bonded with the core film embedded with conductive fine particles sandwiched in the center. In the core film, conductive fine particles 4 made of a copper-silver alloy having an average particle diameter of 6 μm were arranged at a pitch of 15 μm as shown in FIG.

(Performance evaluation)
Using the conductive adhesive sheet produced in Example 4 and the same test substrate 30, substrate D, and glass substrate E as in Example 1, two test pieces were formed in the same manner as in Example 1. A connection confirmation test and a short confirmation test were performed in the same manner as in Example 1.
As a result, in the connection confirmation test, it was confirmed that none of the total 400 connection locations of the two test pieces was not electrically connected to the substrate D.
Moreover, in the short check test, all the insulation resistances were 10 ¹² Ω or more for a total of 398 test pads 35 including two test pieces. As a result, it was confirmed that no short circuit occurred between all the adjacent wirings 32 in all the 398 sets of the wirings 32 of the two test pieces.

[Example 5]
(Production of perforated sheet-like parts)
A perforated sheet-like part 1A shown in FIG. 8 was produced by the following method.
First, as shown in FIG. 14A, a negative photosensitive resin layer 8 having a film thickness of 15 μm is formed on a conductive substrate 7 and a circular light corresponding to the position of the hole 10 is formed thereon. A photomask M1 having a transmission part is arranged, and light is irradiated from above the photomask M1. Next, a predetermined development process is performed to remove a portion of the photosensitive resin layer 8 that was not exposed to light. As a result, a through hole 8 a having a diameter of 6 μm is formed in a portion where the cylindrical body 12 is disposed on the conductive substrate 7. FIG. 14B shows this state. The arrangement of the through holes 8a is the arrangement shown in FIG. 1B, and the length of the unit cell is 12 μm.
Next, the metal layer 13 is grown in the through hole 8a on the conductive substrate by electrolytic plating. At this time, the thickness of the metal layer deposited by the electrolytic plating method was set to 20 μm exceeding the thickness of the photosensitive resin layer. FIG. 14C shows this state. As a result, the metal layer overhangs beyond the photosensitive resin layer, and the diameter of the hole in the overhanged portion can be reduced. Next, the photosensitive resin layer 8 and the conductive substrate 7 cured by being exposed to light are removed (FIG. 14E). Thereby, the perforated sheet-like component 1A having the through holes 10 as shown in FIG. 8 is obtained. The diameter of the hole on one side of the obtained perforated sheet-like part was 6 μm, and the diameter of the hole on the other side was 3 μm.

For the production of the perforated sheet-shaped part, the one having the same composition as the photosensitive resin used for mold production in Example 1 was used.
Before forming the metal layer 13 by the electrolytic plating method, reactive ion etching was performed as a plating pretreatment. Moreover, the back surface of the aluminum substrate 7 was covered with an adhesive film. Using a nickel plating bath, a metal layer composed of a nickel plating film containing a little boron was obtained.
Moreover, the reactive ion etching method in oxygen plasma was used for the removal of the photosensitive resin hardened | cured with light.

(Production of particle adsorption device)
Using the perforated sheet-like part 1A created as described above, the surface with a hole having a diameter of 6 μm was fixed to the porous part 100. A filter paper (manufactured by ADVANTEC) was used as the porous component 100. Thereby, the particle adsorption apparatus 300 shown in FIG. 8 was produced.

(Preparation of conductive adhesive sheet)
In this example, a conductive adhesive sheet is produced by a method corresponding to the example of the fourth method of the present invention. This embodiment will be described with reference to FIG.
First, a sheet composed of a PET film (support) 5 and adhesive layers 2 and 3 was produced by the following method. A polyethylene terephthalate (PET) film having a thickness of 25 μm was prepared, and the surface of this PET film was coated with polydimethylsiloxane as a release agent to a thickness of about 50 nm. An epoxy adhesive solution was applied to the surface of the PET film coated with the release agent using a blade coater. Next, by removing the solvent from the coating film by drying, an adhesive layer made of an epoxy adhesive having a thickness of 10 μm was formed on the PET film. Two sheets of the support coated with an adhesive layer were formed.
The composition of the epoxy adhesive solution used was as follows: bisphenol A type liquid epoxy resin: 10 parts by weight, phenoxy resin: 10 parts by weight, latent hardener comprising microcapsule type imidazole derivative epoxy compound: 4.5 parts by weight, and Toluene / ethyl acetate mixture: 5 parts by weight.

Moreover, the thing of the same composition as the polysulfone resin composition used in Example 2 was prepared, and it used for formation of a core film.
The conductive fine particles 4 are vacuum-adsorbed in the through holes of the particle adsorption device 300 described above, and the polysulfone resin composition is applied to the surface where the conductive fine particles are vacuum-adsorbed, and then the solvent, tetrahydrofuran, is removed by drying to a thickness of 5 μm. A coating was obtained.
Next, the sheet | seat which coat | covered the adhesive bond layer on the already formed support body was adhere | attached by heat-compressing the surface of an adhesive bond layer and the polysulfone resin film which embedded the electroconductive fine particles. Thereafter, the vacuum was released and the sheet on which the polysulfone resin layer and the adhesive layer were bonded was peeled from the particle adsorption device 300.
Further, another adhesive sheet was placed on the core film in which the conductive fine particles were embedded, and the adhesive layer was placed on the core film.

As the conductive fine particles 4, the same fine particles as in Example 1 were used.
By vibrating and moving the particle adsorption device in the container containing the conductive fine particles 4, the conductive fine particles 4 are adsorbed in all the through holes 10a on the adsorption surface. Further, the conductive fine particles adhering to the surface other than the through-hole 10a of the adsorption surface were removed using an adhesive film “SPV-363” manufactured by Nitto Denko Corporation. The adhesive layers 2 and 3 were pressed against the adsorption surface while being heated to 50 ° C.
As described above, a conductive adhesive sheet was obtained in which an adhesive layer composed of two layers of epoxy adhesive was bonded with the core film embedded with conductive fine particles sandwiched in the center. In the core film, conductive fine particles 4 made of a copper-silver alloy having an average particle diameter of 6 μm were arranged at a pitch of 15 μm as shown in FIG.

(Performance evaluation)
Using the conductive adhesive sheet produced in Example 5 and the same test substrate 30, substrate D, and glass substrate as in Example 1, two test pieces were produced in the same manner as in Example 1. Then, a connection confirmation test and a short confirmation test were performed in the same manner as in Example 1.
As a result, in the connection confirmation test, it was confirmed that none of the total 400 connection locations of the two test pieces was not electrically connected to the substrate D.
Moreover, in the short check test, all the insulation resistances were 10 ¹² Ω or more for a total of 398 test pads 35 including two test pieces. As a result, it was confirmed that no short circuit occurred between all the adjacent wirings 32 at all the connection points of the total 398 sets of the two test pieces.

[Comparative Example 1]
(Preparation of conductive adhesive sheet)
The conductive fine particles 4 used in Example 1 were added to the epoxy adhesive solution used in Example 1 at a ratio of 1.2% by volume and mixed. This liquid was applied to the surface of a PET film coated with polydimethylsiloxane as a release agent using a blade coater. Next, by removing the solvent from the coating film by drying, a conductive adhesive sheet having a thickness of 28 μm was formed on the PET film. This conductive adhesive sheet is used after peeling off the PET film.
The addition rate of the conductive fine particles 4 to the epoxy adhesive solution was set so that the content of the conductive fine particles 4 in the conductive adhesive sheet was approximately the same as that in Example 2.

(Performance evaluation)
Using the conductive adhesive sheet produced in Comparative Example 1 and the same test substrate 30, copper plate D, and glass substrate as in Example 1, two test pieces were produced in the same manner as in Example 1. Then, a connection confirmation test and a short confirmation test were performed in the same manner as in Example 1.
As a result, in the connection confirmation test, it was confirmed that four of the 400 connection pads 34 of the two test pieces were not electrically connected to the copper plate D.
Further, in the short check test, all the insulation resistances were 10 ¹² Ω or more for a total of 400 test pads 35 of two test pieces. As a result, it was confirmed that no short circuit occurred between all adjacent connection pads 34 for all 400 connection pads 34 of the two test pieces.

[Comparative Example 2]
A conductive adhesive sheet having the same configuration was produced in the same manner as in Comparative Example 1 except that the addition ratio of the conductive fine particles 4 to the epoxy adhesive solution was 20% by volume.
Using the conductive adhesive sheet produced in Comparative Example 2 and the same test substrate 30, copper plate D, and glass substrate as in Example 1, two test pieces were produced in the same manner as in Example 1. Then, a connection confirmation test and a short confirmation test were performed in the same manner as in Example 1.
As a result, in the connection confirmation test, it was confirmed that all the 400 connection pads 34 of the two test pieces were electrically connected to the copper plate D.
In the short check test, the insulation resistance was 10 ⁸ Ω or less at 10 points out of a total of 400 test pads 35 of 2 test pieces. Thereby, it turned out that the short circuit has generate | occur | produced between the connection pads 34 adjacent in these 10 places.

It is sectional drawing (a-1, a-2) and top view (b, c) which show one Embodiment of the electroconductive adhesive sheet of this invention. FIG. 3 is a diagram for explaining a mold manufacturing method used in the first method of manufacturing the conductive adhesive sheet of the present invention. It is a figure explaining embodiment of the 1st method of manufacturing the electroconductive adhesive sheet of this invention, and Example 1. FIG. It is a figure explaining embodiment and Example 3 of the 2nd method of manufacturing the electroconductive adhesive sheet of this invention. It is a figure explaining embodiment and Example 2 of the 2nd method of manufacturing the electroconductive adhesive sheet of this invention. It is a figure explaining embodiment and Example 4 of the 3rd method which manufactures the electroconductive adhesive sheet of this invention. It is a figure explaining the manufacturing method of the jig | tool for arrange | positioning the electroconductive fine particles used in the 3rd method which manufactures the electroconductive adhesive sheet of this invention in a predetermined position. It is a figure explaining embodiment and Example 5 of the 4th method of manufacturing the electroconductive adhesive sheet of this invention. It is the top view (a) and sectional drawing (b) which show the board | substrate for a test used for the performance evaluation in Examples 1-5 of this invention and Comparative Examples 1 and 2. FIG. It is a figure which shows the state by which the wiring part and board | substrate D of the board | substrate for a test were adhere | attached with the electroconductive adhesive sheet of Examples 1-5, Comprising: It corresponds to the bb sectional view taken on the line bb of FIG. It is a top view (a) which shows the pattern of the board | substrate D used for performance evaluation, and the board | substrate E, (b) is equivalent to the cc sectional view taken on the line of the board | substrate E. It is sectional drawing (a) and a top view (b) which show an example of the conventional conductive adhesive sheet. It is sectional drawing for demonstrating the problem of the conventional electroconductive adhesive sheet. It is a figure explaining the manufacturing method of the perforated sheet-like component for arrange | positioning the electroconductive fine particles used in the 4th method of manufacturing the electroconductive adhesive sheet of this invention in a predetermined position.

Explanation of symbols

1 Core film 2 Adhesive layer (first adhesive layer)
3 Adhesive layer (second adhesive layer)
4 conductive fine particles 5 support 6 cover film 7 conductive substrate 8 photosensitive resin layer 10 through hole 11 photosensitive resin layer 12 electroless plating layer 13 metal layer 20 sheet made of adhesive layer 21 copper cylindrical convex portion 22 made of copper Linear convex portion 23 Core film and adhesive layer 24 Cylindrical convex portion made of glass 25 Glass plate 26 Electrical inspection pad 30 Test substrate 31 Insulating substrate 32 Wiring 35 Inspection pad 170 Conductive particle array jig 171 Concave portion 100 Porous component 300 Particle adsorption device A Position where conductive fine particles do not exist B1 Substrate B2 Substrate C Cross-sectional line in FIG. 11B D Substrate h Wiring height K1 Opening K Metal mask M Exposure mask M1 Photo Mask P1 Connection pattern P2 Connection pattern p Wiring arrangement pitch p10 Cylindrical convex arrangement pitch W Width W2 copper cylindrical projecting part of the diameter of the width W1 copper linear projection portion

Claims (2)

  In the adhesive sheet that imparts conductivity only in the thickness direction of the sheet by the conductive fine particles dispersed and arranged in the sheet surface, an adhesive layer is disposed on both surfaces of the core film disposed in the center in the thickness direction, The core film and the adhesive layer are insulative, and the core film is formed of a resin having a softening temperature that is 20 ° C. or higher than the resin constituting the adhesive layer, and part or all of the individual conductive fine particles are formed. In the method for manufacturing an electrically conductive adhesive sheet having anisotropy that exists in the core film and the conductive fine particles are arranged in a predetermined arrangement in the core film surface, suction holes smaller than the conductive fine particles to be arranged are predetermined. Using an adsorption device having an adsorption surface formed in an arrangement, after adsorbing conductive fine particles on the adsorption surface of this adsorption device, the core film is adsorbed on the adsorbed conductive particles. The conductive fine particles adsorbed on the adsorbing surface are put into the core film by pressing the adsorbing surface from the side toward the adsorbing surface, or by applying a resin solution containing a core film component to the adsorbing surface with a predetermined thickness and drying the solvent. Conductive adhesion characterized by forming an adhesive layer on both sides of the core film after the step of taking in and then releasing the adsorption of the particles by the adsorption device and removing the core film from the adsorption surface Sheet manufacturing method.   The conductive fine particles are fine particles made of copper, gold, silver, nickel, palladium, indium, tin, lead, zinc, bismuth, an alloy of any of these metals, or carbon, or fine particles having a metal coating on the surface. The method for producing a conductive adhesive sheet according to claim 1, wherein:

Images