CN110875101A - Anisotropic conductive film structure and manufacturing method thereof - Google Patents

Abstract

The invention discloses an anisotropic conductive film structure and a manufacturing method thereof, wherein the anisotropic conductive film structure comprises an anisotropic conductive film, an intermediate layer and a non-conductive film, the intermediate layer sandwiched by the anisotropic conductive film and the non-conductive film is used for blocking conductive particles which are not vertically pressurized in the anisotropic conductive film to achieve electrical insulation in the horizontal direction, and simultaneously the conductive particles which are vertically pressurized can flow into the conductive particles which are vertically pressurized and are mutually contacted to achieve electrical conduction in the vertical direction, and the intermediate layer can further prevent the non-conductive film from flowing into the anisotropic conductive film under heating and pressurization, so that the number and the density of the conductive particles are improved, the conductivity is greatly improved, and the specific effect of improving the production efficiency is achieved.

Description

Anisotropic conductive film structure and fabrication method thereof

technical field

The present invention relates to an anisotropic conductive film structure and a manufacturing method thereof, in particular to use an intermediate layer sandwiched by an anisotropic conductive film and a non-conductive film to block the conductive layers in the anisotropic conductive film that are not vertically pressed The particles can achieve electrical insulation in the horizontal direction, and at the same time allow the vertically pressurized conductive particles to flow into the vertically pressed conductive particles and contact each other to achieve electrical conduction in the vertical direction, and the intermediate layer can also It further prevents the non-conductive film from flowing into the anisotropic conductive film under heating and pressure, thereby increasing the number and density of conductive particles, greatly improving the conductivity, and has the specific effect of improving production efficiency.

Background technique

In the field of the electronics industry, it is necessary to electrically connect different electronic components to the electronic circuits on the circuit board, and the most common way is to use solder to achieve soldering, such as lead-tin alloy solder with low temperature melting characteristics and better conductivity , the solder can be melted by heat treatment to contact the electronic components and electronic circuits at the same time, and then the solder is solidified after cooling to firmly connect the electronic components and electronic circuits. With the demand for light, thin, short, and small end products and to achieve power saving characteristics, especially the electronic components of integrated circuits (ICs) need to be further reduced, and for surface mount components (Surface Mount Device, SMD), a high temperature furnace is generally used to speed up the welding process and increase the yield.

In the field of LED and LED displays with increasingly sophisticated products, not only the size of the display panel is increasing, but also the resolution is increasing, so that the driver IC (DriverIC) connected to the panel to provide driving signals to drive each pixel needs to be more closely arranged The pins of electronic components are used to meet the fine pitch requirements of display panels.

Conventional flat-panel displays, such as liquid crystal displays, have replaced conventional cathode ray tube (CRT) displays and are widely used in computer systems, televisions, video display and monitoring devices, and other consumer audio-visual devices. However, with the continuous improvement of the resolution of the flat panel display, the number of pins of the driver integrated circuit (IC) in the flat panel display is also increased, generally reaching hundreds or even thousands of pins. In particular, the demand for thin, thin, and short flat panel displays in the market makes the adjacent pitches (Pitch) in the driving integrated circuit must be narrowed. Due to the very limited available area and the inability to use the traditional soldering method of high temperature soldering, the current mainstream electrical connection technology for liquid crystal modules (LCM) is to use anisotropic conductive film (ACF), such as glass-covered In the process of chip on glass (COG) or chip on film (COF), ACF is used to achieve electrical connection in a specific direction.

Specifically, the anisotropic conductive film is composed of resin and conductive particles (or conductive powder), which can be used to connect two different substrates and circuits, and the anisotropic conductive film has upper and lower (Z-axis) electrical conductivity. It has the characteristics of openness, and the left and right planes (X, Y axes) have insulating properties. Usually, under heating and external pressure treatment in the Z axis direction, the separated conductive particles contained in it can be brought into contact with each other to achieve electrical conductivity in the Z axis direction. The purpose of conduction and electrical insulation in the plane direction at the same time can avoid short circuit between adjacent pins. However, on the basis of the above, with the reduction of the available contact area, it is necessary to increase the content of the conductive powder or increase the particle size of the conductive powder, so as to reduce the resistance and maintain sufficient conduction power, but it will greatly increase the packaging circuit. Therefore, the industry introduces a double-layer composite structure combining ACF and a non-conductive film (Non-Conductive Film, NCF) 30'.

Further, when the double-layer composite structure combining ACF and NCF is actually put into the hot pressing process, due to the material properties, the NCF maintains a very high fluidity, and it is easy to penetrate into the ACF and further push the ACF. The resin' and conductive particles contained in it greatly reduce the number and density of conductive particles per unit area, resulting in the limitation that the conductivity is difficult to improve. Furthermore, in order to maintain specific electrical characteristics and performance, high-quality substrates, components, wires, and anisotropic conductive films must be used in the electrical contact portion, resulting in a substantial increase in process costs and a reduction in overall production efficiency.

Therefore, there is a need for a novel anisotropic conductive film structure and a manufacturing method thereof, which utilizes an intermediate layer sandwiched by an anisotropic conductive film and a non-conductive film to block the anisotropic conductive film from not being vertically pressurized The conductive particles can achieve electrical insulation in the horizontal direction, and at the same time, the conductive particles that have been pressed vertically can flow into the conductive particles that are vertically pressed, and contact each other to achieve electrical conduction in the vertical direction, and the intermediate layer It can further prevent the non-conductive film from flowing into the anisotropic conductive film under heating and pressure, thereby increasing the number and density of conductive particles, greatly improving the conductivity, and having the specific effect of improving production efficiency.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide an anisotropic conductive film structure including sequentially stacked anisotropic conductive films, an intermediate layer and a non-conductive thin film for providing electrical connection function. Specifically, the anisotropic conductive film has an upper surface and a lower surface, and includes a first resin and a plurality of conductive particles, wherein the conductive particles are uniformly distributed in the first resin, and the conductive particles include a polymer core and a conductive shell layer, and the conductive shell layer is to coat the outer surface of the polymer core.

In addition, the intermediate layer has an upper surface and a lower surface, and the lower surface of the intermediate layer is stacked on the upper surface of the anisotropic conductive film, and the non-conductive film includes a second resin and has an upper surface and a lower surface, and is non-conductive The lower surface of the flexible film is stacked on the upper surface of the intermediate layer.

Furthermore, when the anisotropic conductive film structure is heated and vertically pressurized, the conductive particles contained in the vertically pressurized portion of the anisotropic conductive film will be squeezed and flow into the intermediate layer, and the anisotropic conductive film will flow into the intermediate layer. The conductive particles contained in the portion of the conductive film that are not vertically pressed will be blocked by the intermediate layer and remain in the anisotropic conductive film, especially, the intermediate layer can further prevent the non-conductive film from flowing to the anisotropic film under heating and pressure. In the conductive film, the number and density of conductive particles are increased, and the conductivity is greatly improved.

In addition, another object of the present invention is to provide a method for fabricating an anisotropic conductive film structure, comprising: forming an anisotropic conductive film, including a first resin and a plurality of conductive particles, the conductive particles are uniformly distributed on the first resin In a resin, the conductive particles include a polymer core body and a conductive shell layer, and the polymer core body is covered by the conductive shell layer; an intermediate layer is formed, which is located on the anisotropic conductive film and includes intermixed intermediate layers a body and an adhesive; and forming a non-conductive film on the intermediate layer and including a second resin. Furthermore, the above-mentioned conductive shell layer includes a nickel layer and a gold layer, wherein the lower surface of the gold layer covers and surrounds the upper surface of the nickel layer.

Description of drawings

FIG. 1 is a schematic exploded cross-sectional view of an anisotropic conductive film structure according to a first embodiment of the present invention.

FIG. 2 and FIG. 3 are schematic diagrams of the application of the anisotropic conductive film structure according to the first embodiment of the present invention.

FIG. 4 is a flow chart of a method for fabricating an anisotropic conductive film structure according to a second embodiment of the present invention.

Among them, the reference numerals are described as follows:

10 Anisotropic Conductive Film

11 The first resin

12 Conductive particles

12A polymer core

12B Conductive Shell

12C polymer coating

20 middle layer

30 Non-conductive film

40 chips

41 Chip leads

50 glass plates

51 Glass Plate Leads

D1 down direction

D2 up direction

S10, S20, S30 steps

Detailed ways

The embodiments of the present invention are described below by means of specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied by other different specific examples, and various modifications and changes can be made to the details in the description of the present invention based on different viewpoints and applications without departing from the spirit of the present invention.

It should be noted that the structure, proportion, size, number of components, etc. shown in the drawings in this specification are only used to cooperate with the content disclosed in the specification for the understanding and reading of those who are familiar with the technology, and are not intended to limit the scope of the present invention. The limited conditions of implementation, so it has no technical significance. Any structural modification, ratio change or size adjustment, without affecting the effect that the present invention can produce and the purpose that can be achieved, should fall within the scope of the present invention. The technical content disclosed by the invention must be within the scope of coverage.

Please refer to FIG. 1 , which is a schematic exploded cross-sectional view of an anisotropic conductive film structure according to a first embodiment of the present invention. As shown in FIG. 1 , the anisotropic conductive film structure according to the first embodiment of the present invention includes an anisotropic conductive film 10 , an intermediate layer 20 and a non-conductive thin film 30 stacked in sequence, and the intermediate layer 20 is sandwiched between the opposite sides. Between the conductive film 10 and the non-conductive film 30, further, the lower surface of the intermediate layer 20 is stacked on the upper surface of the anisotropic conductive film 10, and the lower surface of the non-conductive film 30 is stacked on the upper surface of the anisotropic conductive film 10. The upper table of the intermediate layer 20 . Furthermore, the anisotropic conductive film 10 includes a first resin 11 and a plurality of conductive particles 12 , wherein the conductive particles 12 are uniformly distributed in the first resin 11 , in particular, each conductive particle 12 includes a polymer core 12A And the conductive shell layer 12B, and the conductive shell layer 12B is to cover the outer surface of the entire polymer core body 12A. In addition, the non-conductive film 30 includes the second resin.

Specifically, the first resin 11 includes a first resin body and a first hardener, wherein the weight percentage of the first resin body is 60%-80%, and the weight% of the first hardener is 20%-30%. In addition, the first resin body includes at least one of epoxy resin, phenoxy resin, acrylic resin, polyurethane resin, urea resin, melamine resin, unsaturated polyester resin, silicone resin, and phenolic resin, The first hardener is at least one of aliphatic amines, alicyclic amines, aromatic amines, polyamides, acid anhydrides, and tertiary amines.

Furthermore, the conductive shell layer 12B may be a multi-layer structure including a nickel layer and a gold layer, wherein the lower surface of the gold layer covers and surrounds the entire upper surface of the nickel layer.

The above-mentioned intermediate layer 20 includes an intermediate layer body and an adhesive that are mixed with each other, wherein the intermediate layer body is at least one of epoxy resin, silicone grease resin, polyurethane resin, unsaturated polyester resin, phenoxy resin, and acrylic resin. One, and the adhesive is at least one of hot melt adhesive, hot melt pressure sensitive adhesive, hot melt adhesive strip, acrylic structural adhesive, epoxy resin adhesive, phenolic resin, urea formaldehyde resin, polyethylene-vinyl acetate resin one. Preferably, the thickness of the intermediate layer 20 is between 1 and 7 μm, and the thickness of the anisotropic conductive film 10 is between 2 and 9 μm.

Further, the second resin of the non-conductive film 30 includes a second resin body and a second hardener, wherein the weight percentage of the second resin body is 32%-63%, and the weight% of the second hardener is 30%-45% %, and the second resin body is at least one of epoxy resin, phenoxy resin, acrylic resin, polyurethane resin, urea resin, melamine resin, unsaturated polyester resin, silicone grease resin, and phenolic resin , and the second hardener is at least one of aliphatic amines, alicyclic amines, aromatic amines, polyamides, acid anhydrides, and tertiary amines. In addition, the second resin may further include a toughening agent to enhance toughness, wherein the toughening agent is at least one of carboxyl-terminated butadiene acrylonitrile, rubber-modified epoxy resin, and close-up dimer acid. Preferably, the thickness of the non-conductive film 30 is between 10 and 40 microns.

In addition, the above-mentioned epoxy resin may include bisphenol A epoxy resin (Bisphenol A, BPA), bisphenol F epoxy resin (Bisphenol F, BPF), dicyclopentadiene epoxy resin (Dicyclopentadiene, DCPD) and at least one of naphthalene epoxy resins.

In practical application, please refer to FIG. 2 and FIG. 3 , which are schematic diagrams of the application of the anisotropic conductive film structure according to the first embodiment of the present invention. In essence, the present invention is used to realize the surface of a chip on glass (COG) package. installation technology.

As shown in FIG. 2 , the chip 40 including a plurality of chip wires 41 is located above the anisotropic conductive film structure of the present invention, and the glass plate 50 including the glass plate wires 51 is located below the anisotropic conductive film structure of the present invention , wherein the chip wire 41 and the glass plate wire 51 are directed toward the anisotropic conductive film structure of the present invention. Further, under heating, the chip 40 and the glass plate 50 face the anisotropic conductive film structure of the present invention in the downward direction D1 and the upward direction D2 respectively, and are simultaneously pressed.

As shown in FIG. 3 , when the chip wire 41 and the glass plate wire 51 are close to each other and are pressed against the non-conductive film 30 and the anisotropic conductive film 10 respectively, the anisotropic conductive film 10 is not perpendicular to the The conductive particles 12 contained in the pressurized portion remain in the anisotropic conductive film and cannot flow to the intermediate layer 20, but the conductive particles 12 contained in the vertically pressurized portion of the anisotropic conductive film 10 are blocked. Squeeze and flow, and then flow into the intermediate layer 20 . At this time, the conductive particles 12 are in contact with each other, that is, the conductive shell layers 12B are in contact with each other to electrically connect the corresponding chip wires 41 and glass plate wires 51 .

In particular, the intermediate layer 20 can further prevent the non-conductive film 30 from flowing into the anisotropic conductive film 10 under heating and pressure, thereby solving the problem that the conductivity is difficult to increase due to the large reduction in the number and density of conductive particles.

Therefore, since the spaced regions between adjacent chip wires 41 and the spaced regions between adjacent glass plate wires 51 are not squeezed, there is no conductive particle 12 in contact with each other to provide electrical connection, which is essentially an electrical connection in the horizontal direction. The conductive particles 12 squeezed by the chip wire 41 and the glass plate wire 51 are electrically connected because of mutual contact, so the chip wire 41 and the glass plate wire 51 are essentially electrically connected in the vertical direction. pass, specifically to achieve the purpose of COG.

In the above application example, the conditions of the hot-pressing treatment may be 200 degrees Celsius, 5 MPa pressure, and 10 seconds duration. At this time, the average capture rate of the conductive particles 12 can be changed from 15 of the double-layer composite structure of the prior art. % is increased to 31.21%, not only the number of effective conductive particles 12 remaining in the overall structure is large, but also the distribution of conductive particles 12 is more uniform because of the intermediate layer 20, which greatly improves the electrical characteristics.

In addition, the anisotropic conductive film structure according to the first embodiment of the present invention may further include a polymer coating layer 12C, which surrounds the entire outer surface of the conductive shell layer 12B and has ductility. Therefore, under external stress, high The molecular coating layer 12C is deformed and ruptured, and part of the surface of the underlying conductive shell layer 12B is exposed, and the adjacent conductive shell layers 12B can be electrically connected by contact.

Further referring to FIG. 4 , a flowchart of a method for fabricating an anisotropic conductive film structure according to a second embodiment of the present invention. As shown in FIG. 4 , the method for fabricating the anisotropic conductive film structure according to the second embodiment of the present invention includes steps S10 , S20 and S30 for fabricating the anisotropic conductive film structure.

First, the method for fabricating an anisotropic conductive film structure according to the second embodiment of the present invention starts from step S10 to form an anisotropic conductive film, wherein the anisotropic conductive film includes a first resin and a plurality of conductive particles, and a plurality of conductive particles are formed. The conductive particles are uniformly distributed in the first resin, and each conductive particle includes a polymer core body and a conductive shell layer, and the polymer core body is covered by the conductive shell layer. Next, in step S20, an intermediate layer is formed, which is located on the anisotropic conductive film and includes the intermediate layer body and the adhesive. Finally, step S30 is performed to form a non-conductive thin film, which is located on the intermediate layer and includes the second resin.

Since the structure of the anisotropic conductive film fabricated in the second embodiment is the same as that of the first embodiment, the characteristics of the anisotropic conductive film, the intermediate layer and the non-conductive thin film will be described again.

To sum up, the feature of the present invention lies in the use of a special laminated structure, especially the use of the intermediate layer sandwiched by the anisotropic conductive film and the non-conductive film to block the anisotropic conductive film that is not vertically pressed. The conductive particles are used to achieve the purpose of electrical insulation in the horizontal direction, and at the same time, the conductive particles that have been vertically pressed can flow into the vertically pressed conductive particles and contact each other to achieve the purpose of electrical conduction in the vertical direction. In particular, the intermediate layer can further block the flow of the non-conductive film into the anisotropic conductive film under heating and pressure, thereby solving the problem that the conductivity is difficult to increase due to the large reduction in the number and density of conductive particles. In addition, the present invention can be realized by a low-cost manufacturing method, can greatly improve the electrical conductivity, reduce the overall process cost, and has the specific effect of improving the production efficiency.

The above descriptions are only used to explain the preferred embodiments of the present invention, and are not intended to limit the present invention in any form. It should still be included in the scope of the intended protection of the present invention.

Claims (10)

1. an anisotropic conductive film structure, is characterized in that, comprises: An anisotropic conductive film has an upper surface and a lower surface, and includes a first resin and a plurality of conductive particles, the conductive particles are uniformly distributed in the first resin, and the conductive particles include a polymer core body and a conductive shell layer, and the conductive shell layer coats an outer surface of the polymer core body; an intermediate layer having an upper surface and a lower surface, and the lower surface of the intermediate layer is stacked on the upper surface of the anisotropic conductive film; and a non-conductive film comprising a second resin and having an upper surface and a lower surface, the lower surface of the non-conductive film is stacked on the upper surface of the intermediate layer, Wherein, when the anisotropic conductive film structure is heated and vertically pressurized, the conductive particles contained in the vertically pressurized portion of the anisotropic conductive film are squeezed and flow into the intermediate layer, and the anisotropic conductive film The conductive particles contained in the portion of the square conductive film that are not vertically pressed are blocked by the intermediate layer and remain in the anisotropic conductive film, and the intermediate layer further blocks the non-conductive film from flowing to the surface of the non-conductive film under heating and pressure. inside the anisotropic conductive film. 2 . The anisotropic conductive film structure according to claim 1 , wherein the intermediate layer comprises an intermediate layer body and an adhesive which are mixed with each other, and the intermediate layer body comprises epoxy resin, silicone resin, polyurethane At least one of resin, unsaturated polyester resin, phenoxy resin and acrylic resin, and the adhesive includes hot melt adhesive, hot melt pressure sensitive adhesive, hot melt adhesive strip, acrylic structural adhesive, epoxy resin At least one of resin glue, phenolic resin, urea formaldehyde resin and polyethylene-vinyl acetate resin. 3. The anisotropic conductive film structure of claim 1, wherein a thickness of the intermediate layer is between 1 and 7 microns, and the conductive shell layer comprises a nickel layer and a gold layer, The lower surface of the gold layer covers and surrounds an upper surface of the nickel layer. 4 . The anisotropic conductive film structure according to claim 1 , wherein the first resin of the anisotropic conductive film comprises a first resin body with a weight percentage of 60% to 80% and a weight percentage of 20%. 5 . %～30% of a first hardener, and the first resin body includes epoxy resin, phenoxy resin, acrylic resin, polyurethane resin, urea resin, melamine resin, unsaturated polyester resin, silicone grease At least one of resin and phenolic resin, and the first hardener includes at least one of aliphatic amine, alicyclic amine, aromatic amine, polyamide, acid anhydride, and tertiary amine. 5 . The anisotropic conductive film structure of claim 4 , wherein a thickness of the anisotropic conductive film is between 2 and 9 μm. 6 . 6 . The anisotropic conductive film structure according to claim 1 , wherein the second resin comprises: a second resin body with a weight percentage of 32% to 63% and a second resin body with a weight percentage of 30% to 45% . The second hardener, the second resin body includes at least one of epoxy resin, phenoxy resin, acrylic resin, polyurethane resin, urea resin, melamine resin, unsaturated polyester resin, silicone resin, and phenolic resin and the second hardener includes at least one of aliphatic amine, alicyclic amine, aromatic amine, polyamide, acid anhydride, and tertiary amine. 7 . The anisotropic conductive film structure of claim 6 , wherein the second resin of the non-conductive film further comprises a toughening agent, and the toughening agent comprises carboxyl-terminated butadiene acrylonitrile, At least one of rubber-modified epoxy resin and close-up dimer acid. 8 . The anisotropic conductive film structure of claim 1 , wherein a thickness of the non-conductive film is between 10 and 40 μm. 9 . 9. A method for making an anisotropic conductive film structure, comprising the following steps: An anisotropic conductive film is formed, the anisotropic conductive film includes a first resin and a plurality of conductive particles, the conductive particles are uniformly distributed in the first resin, and the conductive particles include a polymer core and a conductive shell, and the polymer core is covered by the conductive shell; forming an intermediate layer on the anisotropic conductive film and comprising an intermediate layer body and an adhesive mixed with each other; and forming a non-conductive film on the intermediate layer and comprising a second resin, The conductive shell layer includes a nickel layer and a gold layer, and a lower surface of the gold layer covers and surrounds an upper surface of the nickel layer. 10 . The method for fabricating an anisotropic conductive film structure as claimed in claim 9 , wherein a thickness of the intermediate layer is between 1 and 7 μm, and the intermediate layer body comprises epoxy resin and silicone resin. 11 . , at least one of polyurethane resin, unsaturated polyester resin, phenoxy resin and acrylic resin, the adhesive includes hot melt adhesive, hot melt pressure sensitive adhesive, hot melt adhesive strip, acrylic structural adhesive, ring At least one of oxygen grease, phenolic resin, urea formaldehyde resin and polyethylene-vinyl acetate resin.

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