TW202129784A - Method for producing connected structure - Google Patents

Abstract

The present invention provides a method for producing a connected structure, which comprises a connection step for connecting a substrate 5 and a circuit component 4 having a projected electrode 42 with an anisotropic conductive film 9 being interposed therebetween, said anisotropic conductive film 9 being obtained by dispersing conductive particles 7 in an adhesive layer 8. With respect to the anisotropic conductive film 9, the conductive particles 7 are unevenly gathered in one surface of the anisotropic conductive film 9. The connection step comprises a temporary fixing step wherein the anisotropic conductive film 9 is arranged between the circuit component 4 and the substrate 5 such that the above-described one surface faces the substrate 5, and the projected electrode 42 is pressed into the anisotropic conductive film 9 so that the distance d between a surface 42a of the projected electrode 42 and a surface 5a of the substrate 5 is 150% or less of the average particle diameter of the conductive particles 7.

Description

Manufacturing method of connecting structure

The invention relates to a method for manufacturing a connecting structure.

When a substrate such as a glass panel for liquid crystal display (glass panel) is connected to circuit components such as an integrated circuit (IC) for driving liquid crystal to produce a connected structure, it is used to disperse conductive particles in an adhesive layer. In the case of anisotropic conductive film (film). In this case, the plurality of bump electrodes provided on the circuit component can be collectively connected to the substrate.

In recent years, with the development of electronic equipment, the density of wiring and the higher functionality of circuits are being advanced. As a result, the area and pitch of the protruding electrodes are being reduced. In order to obtain a stable electrical connection in the connection of such a bump electrode, a sufficient number of conductive particles must be interposed between the bump electrode and the substrate.

In response to such a problem, for example, Patent Document 1 discloses a method of manufacturing a connection structure using an anisotropic conductive film in which conductive particles are present in the vicinity of one side surface of the anisotropic conductive film. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2007-103545

[The problem to be solved by the invention] However, even when the above-mentioned conventional anisotropic conductive film is used, there are cases where the adhesive component of the anisotropic conductive film flows when heating and pressing are performed to manufacture a connected structure, and accordingly, the conductive The particles flow out from between the protruding electrode and the substrate. At this time, there is a concern that a sufficient number of conductive particles may not be interposed between the protruding electrode and the substrate.

The present invention was made to solve the above-mentioned problems, and an object thereof is to provide a method of manufacturing a connection structure capable of interposing a sufficient number of conductive particles between a protruding electrode and a substrate. [Means to solve the problem]

In order to solve the above-mentioned problems, the manufacturing method of the connected structure of the present invention includes a connecting step of connecting a circuit component having a protruding electrode and a substrate through an anisotropic conductive film formed by dispersing conductive particles in an adhesive layer For the connection, an anisotropic conductive film in which conductive particles are concentrated on one side of the anisotropic conductive film is used as the anisotropic conductive film, and the connecting step includes a temporary fixing step that aligns the anisotropic conductive film on one side. The side facing the substrate side is arranged between the circuit part and the substrate, and the bump electrode is pressed into the opposite direction so that the distance between the surface of the bump electrode and the surface of the substrate becomes 150% or less of the average particle size of the conductive particles In the conductive film.

In the manufacturing method of the connecting structure, the bump electrode is pressed into the anisotropic conductive film so that the distance between the surface of the bump electrode and the surface of the substrate becomes 150% or less of the average particle diameter of the conductive particles , The adhesive component of the anisotropic conductive film can be removed from between the protruding electrode and the substrate in advance. As a result, the adhesive component existing between the protruding electrode and the substrate is reduced, so even when the adhesive component flows due to the heating and pressurization in the subsequent main fixing step, it is possible to prevent the conductive particles from becoming self-contained. Flow out between the bump electrode and the substrate. Therefore, the conductive particles can be better trapped between the protruding electrode and the substrate. Therefore, in the obtained connection structure, a sufficient number of conductive particles can be interposed between the protruding electrode and the substrate.

In the temporary fixing step, the bump electrode can be pressed into the anisotropic conductive film so that the distance between the surface of the bump electrode and the surface of the substrate becomes 100% or less of the average particle diameter of the conductive particles. At this time, the conductive particles are temporarily fixed in a state in which the conductive particles are in contact with the protruding electrode and the substrate, so that the conductive particles can be better captured between the protruding electrode and the substrate.

In the temporary fixing step, the bump electrode can be pressed into the anisotropic conductive film so that the distance between the surface of the bump electrode and the surface of the substrate becomes less than 100% of the average particle diameter of the conductive particles. At this time, in the temporary fixing step, the conductive particles are caught between the protruding electrode and the substrate. Therefore, the outflow of the conductive particles caused by the flow of the adhesive component of the anisotropic conductive film is further suppressed, thereby The conductive particles can be better trapped between the protruding electrode and the substrate.

The connection step further includes a formal fixing step after the temporary fixing step. The formal fixing step further presses the protruding electrode into the anisotropic conductive film while heating, thereby electrically connecting the protruding electrode and the substrate via conductive particles. . At this time, since the adhesive component has been removed from between the bump electrode and the substrate in the temporary fixing step, the bump electrode is further pressed into the anisotropic conductive film even when heating is performed in the formal fixing step It can also prevent the conductive particles from flowing out between the protruding electrode and the substrate, so that the conductive particles can be better trapped between the protruding electrode and the substrate. Therefore, in the connection structure, a sufficient number of conductive particles can be interposed between the protruding electrode and the substrate. [Effects of the invention]

According to the present invention, a sufficient number of conductive particles can be interposed between the protruding electrode and the substrate.

Hereinafter, with reference to the drawings, an embodiment of the method of manufacturing the connection structure of the present invention will be described in detail.

Fig. 1 is a plan view showing an electronic device to which a connection structure according to an embodiment of the present invention is applied. As shown in FIG. 1, the connection structure 1 is applied to an electronic device 2 such as a touch panel, for example. The electronic device 2 includes, for example, a liquid crystal panel 3 and circuit components 4.

The liquid crystal panel 3 has, for example, a substrate 5 and a liquid crystal display unit 6. The substrate 5 has, for example, a rectangular plate shape with a size of 20 mm to 300 mm×20 mm to 400 mm and a thickness of 0.1 mm to 0.3 mm. As the substrate 5, for example, a glass substrate formed of non-alkali glass or the like can be used. On the surface 5 a of the substrate 5, circuit electrodes (not shown) are formed so as to correspond to the protrusion electrodes 42 (described later) of the liquid crystal display portion 6 and the circuit component 4. The liquid crystal display portion 6 is mounted on the surface 5a of the substrate 5 and is connected to the circuit electrodes.

The circuit component 4 has a rectangular plate shape smaller than the substrate 5, and has a size of, for example, 0.6 mm to 3.0 mm×10 mm to 50 mm, for example, a thickness of 0.1 mm to 0.3 mm. The circuit component 4 is spaced apart from the liquid crystal display portion 6 and is connected to the circuit electrode of the substrate 5 (details will be described later).

Fig. 2 is a plan view showing the connection structure. As shown in FIG. 2, the circuit component 4 has a main body 41 and protruding electrodes 42 provided on the main body 41. The main body 41 has a mounting surface 41a and a non-mounting surface 41b on the opposite side of the mounting surface 41a. In the connection structure 1, the circuit components 4 are arranged so that the substrate 5 faces the mounting surface 41a. The main body 41 is formed with a plurality of protruding electrodes (for example, bump electrodes) 42 protruding from the mounting surface 41 a. As a material for forming the main body portion 41 of the circuit component 4, silicon or the like can be used. The protruding electrode 42 is formed of a material (Au etc.) softer than conductive particles (details will be described later) contained in the anisotropic conductive film.

As shown in FIG. 2, on the mounting surface 41a, for example, along one of the long sides 41c of the mounting surface 41a, a plurality of protruding electrodes 42 are arranged at substantially equal intervals in a row, and along the other long side 41d of the mounting surface 41a, The plurality of protruding electrodes 42 are arranged across three rows at substantially equal intervals and in a zigzag manner. One row of protruding electrodes 42 arranged on the side of one long side 41c are, for example, electrodes on the input side, and three rows of protruding electrodes 42 arranged on the side of the other long side 41d are, for example, electrodes on the output side. The bump electrode 42 has a height (height from the mounting surface 41a) of, for example, 2 μm to 15 μm. In addition, on the mounting surface 41a, a plurality of protruding electrodes 42 can also be arranged along one of the long sides 41c to span, for example, two to four rows, and a plurality of protruding electrodes 42 can also be spanned along the other long side 41d. And, for example, two rows or four rows are arranged.

Fig. 3 is a schematic cross-sectional view showing a cross section in the direction of the arrow I-I in Fig. 2. As shown in FIG. 3, in the connection structure 1, the circuit components 4 and the substrate 5 are connected to each other via an anisotropic conductive film 9 in which conductive particles 7 are dispersed in an adhesive layer 8.

As the adhesive component constituting the adhesive layer 8 of the anisotropic conductive film 9, materials that exhibit curability by heat or light can be widely used. For example, epoxy-based adhesives or acrylic-based adhesives can be used. . In terms of excellent heat resistance and moisture resistance after connection, a crosslinkable material can be preferably used. Among them, epoxy-based adhesives containing an epoxy resin as a thermosetting resin as a main component can be preferably used from the viewpoints that they can be cured in a short time, have good connection workability, and are excellent in adhesiveness.

As specific examples of epoxy adhesives, adhesives mainly composed of high molecular weight epoxy resins, solid epoxy resins, or liquid epoxy resins, or the use of urethane, poly Ester, acrylic rubber, nitrile rubber (Nitrile Rubber, NBR), synthetic linear polyamide, etc. modified epoxy resin modified from these epoxy resins. The epoxy-based adhesive usually contains the epoxy resin as a main component, as well as a hardener, a catalyst, a coupling agent, a filler, and the like.

Specific examples of acrylic adhesives include adhesives containing acrylic resin (polymer or copolymer) as a main component, and the acrylic resin contains at least one of acrylic acid, acrylate, methacrylate, and acrylonitrile. As a monomer component.

Examples of the conductive particles 7 contained in the anisotropic conductive film 9 include particles formed of metals such as Au, Ag, Pt, Ni, Cu, W, Sb, Sn, solder, and conductive carbon. The conductive particles 7 may also be coated particles that take a particle made of non-conductive glass, ceramic, plastic, etc. as the core, and coat the core with the metal, conductive carbon, etc. Become. Examples of the shape of the conductive particles 7 before connection include a substantially spherical shape, a shape in which a plurality of protrusions protrude in the radial direction (star shape), and the like.

Regarding the average particle diameter of the conductive particles 7 before connection, from the viewpoint of dispersibility and conductivity, it is preferably 1 μm to 18 μm, and more preferably 2 μm to 4 μm. Within this range, it is preferable to use conductive particles having an average particle diameter larger than the height of the protruding electrode 42, but conductive particles having an average particle diameter of the height of the protruding electrode 42 may be used, for example, 80% to 100%. The average particle size of the conductive particles 7 can be obtained by the following method: For 300 arbitrary conductive particles, the particle size is measured by observation with a scanning electron microscope (Scanning Electron Microscope, SEM), and the size of these particle sizes average value. When the conductive particles 7 have protrusions and the like and are not spherical, the particle diameter of the conductive particles 7 may be the diameter of a circle circumscribed to the conductive particles in the SEM image.

Next, the manufacturing method of the connection structure of this embodiment is demonstrated. The manufacturing method of the connected structure of the present embodiment includes a connecting step including a temporary fixing step and a formal fixing step. 4(a) and 4(b) are schematic cross-sectional views showing the temporary fixing step in the method of manufacturing the connection structure. In the temporary fixing step, as shown in FIG. 4(a), an anisotropic conductive film in which conductive particles 7 are concentrated on one surface 9a of the anisotropic conductive film 9 is used as the anisotropic conductive film 9, and the anisotropic conductive film 9 is The anisotropic conductive film 9 is arranged between the circuit component 4 and the substrate 5 (on the surface 5 a of the substrate 5) such that the one surface 9 a side of the conductive film 9 faces the substrate 5 side.

The thickness of the anisotropic conductive film 9 can be, for example, 5 μm to 30 μm. The distance between the conductive particles 7 only on the side 9a of the anisotropic conductive film 9 is preferably 150% or less of the average particle diameter of the conductive particles 7, more preferably 130% or less, and still more preferably 110% The following range.

In the anisotropic conductive film 9, the method for concentrating the conductive particles 7 on the one surface 9a side of the anisotropic conductive film 9 is not particularly limited. For example, an anisotropic conductive film in which conductive particles 7 are concentrated on one side 9a of an anisotropic conductive film 9 can be conductive by laminating an insulating adhesive layer that does not contain conductive particles 7 on one side. The adhesive layer is formed. At this time, the thickness of the conductive adhesive layer is preferably, for example, 0.6 times or more and less than 1.0 times the average particle diameter of the conductive particles 7.

Regarding the content of the conductive particles 7 in the anisotropic conductive film 9, from the viewpoint of preventing short circuits caused by the excessive presence of conductive particles 7, it is 100% relative to the content of the conductive particles 7 in the anisotropic conductive film 9 The parts by volume are preferably 1 part by volume to 100 parts by volume, more preferably 10 parts by volume to 50 parts by volume. The anisotropic conductive film 9, the conductive particles may be particles of, for example, the density of 7 5000 / mm ² or more and 50000 / mm ² or less.

In the temporary fixing step, then, as shown in FIG. 4(b), the circuit component 4 and the substrate 5 (the direction of the arrow in FIG. 4(b)) are pressed while heating, and the circuit The protruding electrode 42 of the component 4 is press-fitted into the anisotropic conductive film 9. The heating temperature and pressure at this time are preferably such that the adhesive component of the anisotropic conductive film 9 flows and the conductive particles 7 can be kept from flowing out between the protruding electrode 42 and the substrate 5 , And are respectively below the heating temperature and pressure in the subsequent formal fixing step. Specifically, the heating temperature is, for example, 40° C. to 100° C., and the pressure is, for example, 2 MPa to 10 MPa with respect to the total electrode area of the protruding electrodes 42 of the circuit component 4.

Fig. 5 is an enlarged schematic cross-sectional view of the main part of Fig. 4(b). As shown in FIG. 5, in the temporary fixing step, the distance d between the surface 42a of the protruding electrode 42 and the surface 5a of the substrate 5 relative to the average particle size of the conductive particles 7 is preferably 150% or less, more preferably 120% or less, more preferably 100% or less, and particularly preferably less than 100%, the protruding electrode 42 of the circuit component 4 is pressed into the anisotropic conductive film 9. On the other hand, the distance d may be, for example, 0.4 times (40%) or more with respect to the average particle diameter of the conductive particles 7. By setting the distance d as described above, good connection reliability can be obtained in the connection structure after the formal fixing step described later. The distance d between the surface 42a of the protruding electrode 42 and the surface 5a of the substrate 5 can be calculated as follows: for example, using a metal microscope to observe the temporarily fixed circuit component 4 and the substrate 5 from the side of the substrate 5, according to the surface 42a of the protruding electrode 42 The difference between the focal length and the focal length of the surface 5a of the substrate 5 is calculated.

In the manufacturing method of the connected structure of the present embodiment, the main fixing step is performed after the temporary fixing step. Fig. 6 is a schematic cross-sectional view showing a formal fixing step. As shown in FIG. 6, in the formal fixing step, by heating the circuit component 4, the substrate 5, and the anisotropic conductive film 9, the circuit component 4 and the substrate 5 are simultaneously added to the opposing direction (the direction of the arrow in FIG. 6). Then, the protruding electrode 42 of the circuit component 4 is further pressed into the anisotropic conductive film 9. The heating temperature and pressure at this time are respectively equal to or higher than the heating temperature and pressure in the temporary fixing step. Specifically, the heating temperature is, for example, 100° C. to 200° C., and the pressure is, for example, 20 MPa to 100 MPa with respect to the total electrode area of the protruding electrodes 42 of the circuit component 4.

As a result, the adhesive component of the anisotropic conductive film 9 further flows, and the distance d between the surface 42a of the protruding electrode 42 and the surface 5a of the substrate 5 is further shortened. As a result, the oblateness of the conductive particles 7 becomes, for example, 30% or more, so that the connection between the circuit component 4 and the substrate 5 is secured. Furthermore, by hardening the adhesive layer 8 in a state where the conductive particles 7 are bitten between the protruding electrode 42 and the substrate 5, the protruding electrode 42 and the corresponding circuit electrode (not shown) of the substrate 5 pass through The conductive particles 7 are electrically connected, and the adjacent protruding electrodes 42 and the adjacent circuit electrodes are electrically insulated from each other to obtain the connection structure 1 shown in FIG. 3. In addition, when the adhesive component of the anisotropic conductive film 9 contains a photocurable resin, the adhesive layer 8 is cured by irradiating, for example, ultraviolet light while heating and pressing in the main fixing step. That's it.

In the method of manufacturing the connection structure, in the temporary fixing step, the protrusions are preliminarily preliminarily fixed so that the distance d between the surface 42a of the protruding electrode 42 and the surface 5a of the substrate 5 becomes 150% or less of the average particle diameter of the conductive particles. After the electrode 42 is pressed into the anisotropic conductive film 9, in the main fixing step, the protruding electrode 42 is further pressed into the anisotropic conductive film 9. Here, in the conventional manufacturing method of the connected structure that performs the main fixing step without performing the temporary fixing step, the adhesive component of the anisotropic conductive film flows all at once in the main fixing step. Therefore, there is a concern that with the rapid flow of the adhesive components, conductive particles flow out between the protruding electrode and the substrate, and a sufficient number of conductive particles may not be interposed between the protruding electrode and the substrate.

On the other hand, in the manufacturing method of the connection structure, the adhesive component of the anisotropic conductive film 9 can be removed from between the protruding electrode 42 and the substrate 5 by performing the temporary fixing step. As a result, the adhesive component existing between the protruding electrode 42 and the substrate 5 is reduced, so even when the adhesive component flows due to heating and pressure in the subsequent main fixing step, electrical conduction can be suppressed. The particles 7 flow out from between the protruding electrode 42 and the substrate 5. Therefore, the conductive particles 7 are better captured between the protruding electrode 42 and the substrate 5. Therefore, in the obtained connection structure 1, a sufficient number of conductive particles 7 can be interposed between the protruding electrode 42 and the substrate 5. between.

The above-mentioned effect is remarkably exhibited when the anisotropic conductive film in which the conductive particles 7 are concentrated on the one surface 9a side of the anisotropic conductive film 9 is used as the anisotropic conductive film 9. As for the reason, from the viewpoint of the fluidity of the fluid, the fluidity of the adhesive component on the interface side (one side 9a side) of the anisotropic conductive film 9 with the substrate 5 is lower than that of the anisotropic conductive film 9. The fluidity of the adhesive components in the central part. Therefore, the flow of the conductive particles 7 concentrated on the side 9a with low fluidity is suppressed more than the conductive particles 7 arranged in the entire anisotropic conductive film, and it is considered that the above-mentioned effect is exerted significantly.

In addition, in the temporary fixing step, the bump electrode 42 is pressed into the opposite direction so that the distance d between the surface 42a of the bump electrode 42 and the surface 5a of the substrate 5 becomes 100% or less of the average particle diameter of the conductive particles 7 In the case of the conductive film 9, the conductive particles 7 are temporarily fixed in a state in which the conductive particles 7 are in contact with the protruding electrodes 42 and the substrate 5. Therefore, the conductive particles 7 can be better captured between the protruding electrodes 42 and the substrate 5.

In addition, in the temporary fixing step, the bump electrode 42 is pressed into the opposite direction so that the distance d between the surface 42a of the bump electrode 42 and the surface 5a of the substrate 5 becomes less than 100% of the average particle diameter of the conductive particles 7 In the case of the conductive film 9, the conductive particles 7 are caught between the protruding electrode 42 and the substrate 5 during the temporary fixation step, and therefore, it is caused by the flow of the adhesive component of the anisotropic conductive film 9 The outflow of the conductive particles 7 is further suppressed, and the conductive particles 7 can be better captured between the protruding electrode 42 and the substrate 5. [Example]

Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

[Example 1-1 to Example 1-3, Comparative Example 1-1] (Synthesis of phenoxy resin a) Put 4 ,4'-(9-ylidene)-diphenol 45 g (manufactured by Sigma-Aldrich Japan Co., Ltd.), and 3,3',5,5'-tetramethylbiphenol 50 g of diglycidyl ether (manufactured by Mitsubishi Chemical Corporation: YX-4000H) was dissolved in 1000 mL of N-methylpyrrolidone to prepare a reaction liquid. 21 g of potassium carbonate was added thereto, and the mixture was stirred while being heated to 110°C with a mantle heater. After stirring for 3 hours, the reaction solution was dropped into a beaker containing 1000 mL of methanol, and the generated precipitate was filtered off by suction. The filtered precipitate was further washed 3 times with 300 mL of methanol to obtain 75 g of phenoxy resin a.

After that, the molecular weight of the phenoxy resin a was measured using a high performance liquid chromatograph (High Performance Liquid Chromatograph) GP8020 manufactured by Tosoh Co., Ltd. (the measurement conditions are as described above). As a result, Mn=15769, Mw=38045, Mw/Mn=2.413 in terms of styrene.

(Production of anisotropic conductive film A) When forming the adhesive paste for the conductive adhesive layer, 50 parts by mass of bisphenol A epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd.: jER828) is an epoxy compound in terms of solid content. ), 5 parts by mass of 4-hydroxyphenylmethylbenzyl hexafluoroantimonate as a hardener based on solid content, and 50 parts by mass of phenoxy resin as a film forming material based on solid content a. Furthermore, as conductive particles, a nickel layer with a thickness of 0.2 μm was provided on the surface of particles with styrene as the core, and conductive particles with an average particle diameter of 3.3 μm and a specific gravity of 2.5 were produced. It is further formulated into the formulation. Then, using a coater, the adhesive paste was applied to a polyethylene terephthalate (PET) film with a thickness of 50 μm and dried to obtain a PET film. A conductive adhesive layer with a thickness of 3 μm on the film.

Next, when forming the adhesive paste for the insulating adhesive layer, 45 parts by mass of bisphenol F epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd.: jER807) as an epoxy compound is blended in terms of solid content. , 5 parts by mass of 4-hydroxyphenylmethylbenzyl hexafluoroantimonate as a hardening agent in terms of solid content, and 55 parts by mass of bisphenol A·bis as a film forming material in terms of solid content Phenol F copolymerized phenoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.: YP-70). Then, the adhesive paste was coated on a PET film with a thickness of 50 μm using a coater and dried, thereby obtaining an insulating adhesive layer with a thickness of 14 μm formed on the PET film. After that, the conductive adhesive layer and the insulating adhesive layer were heated to 40° C. and bonded using a hot roll laminator to obtain an anisotropic conductive film A sandwiched between the PET films .

For the obtained anisotropic conductive film A, the ^{number of conductive particles per 25000 μm 2} was measured at 20 locations, and the average value was converted to the number of conductive particles ^{per 1 mm 2.} As a result, the density of conductive particles in the anisotropic conductive film A was 280,000 particles/mm ² .

(Fabrication of the connection structure) As a circuit part, prepare an IC chip with bump electrodes arranged (outer shape 2 mm×20 mm, thickness 0.3 mm, bump electrode area 840 μm ² (length 70 μm) × 12 μm across), the space between bump electrodes is 12 μm, and the height of bump electrodes is 15 μm). Furthermore, as a substrate, a wiring pattern (Indium Tin Oxide, ITO) formed on the surface of a glass substrate (Corning: #1737, 38 mm×28 mm, thickness 0.3 mm) is prepared. ) (Pattern width is 31 μm, the space between electrodes is 7 μm) substrate.

A thermocompression bonding device is used when connecting the IC chip and the glass substrate. The thermocompression bonding device includes a stage (150 mm×150 mm) containing a ceramic heater and a tool (3 mm×20) mm). Then, peel off the PET film on the conductive adhesive layer side of the anisotropic conductive film A (2.5 mm×25 mm), and heat and press for 2 seconds under the conditions of 80°C and 0.98 MPa to increase the conductivity The surface on the side of the adhesive layer is attached to the glass substrate.

Then, after aligning the positions of the bump electrodes of the IC chip and the circuit electrodes of the glass substrate, heating and pressing were performed for 1 second at the temporary fixed temperature and the temporary fixed pressure shown in Table 1, and the bumps of the IC chip The electrode is pressed into the anisotropic conductive film A. Table 1 shows the distance between the temporarily fixed glass substrate and the bump electrode. In addition, the distance between the temporarily fixed substrate and the bump electrode was observed from the glass substrate side using a metal microscope, and was calculated from the difference between the focal length of the surface of the glass substrate and the focal length of the bump electrode.

Then, heating and pressing were performed for 5 seconds under the conditions of 160° C. and 70 MPa, thereby formally fixing the IC wafer to the glass substrate to obtain a connected structure. The capture rate of conductive particles in the connected structure was calculated based on the following formula. Capture rate (%) = (number of conductive particles on bump electrode / (1 mm ² / bump electrode area) / ^{number of conductive particles per 1 mm 2} of the anisotropic conductive film) × 100 In addition, using a metal microscope, The number of conductive particles was actually measured at 200 locations of the bump electrode, and the average value was set as the number of conductive particles on the bump electrode. The results are shown in Table 1.

[Table 1] Comparative example 1-1 Example 1-1 Example 1-2 Example 1-3 Average diameter of conductive particles Dp[μm] 3.3 Particle density of conductive particles [pcs/mm ² ] 28000 Adhesive layer composition Insulating adhesive layer [μm] 14 Conductive adhesive layer [μm] 3 Bump electrode configuration Area [μm ² ] 840 Height [μm] 15 Temporarily fix temperature [℃] 30 50 70 90 Temporarily fixed pressure [MPa] 3.3 Distance between substrate and bump electrode d[μm] 9.4 4.8 2.4 1.8 d/Dp×100[%] 285 145 73 55 Capture rate of conductive particles [%] 58.9 60.7 62.6 63.3

[Example 2-1 to Example 2-2, Comparative Example 2-1] (Production of anisotropic conductive film B) Instead of phenoxy resin a, bisphenol A type phenoxy resin (Nippon Steel & Sumikin Chemical Co., Ltd. product: YP-50), instead of bisphenol A and bisphenol F copolymerized phenoxy resin (Nippon Steel & Sumikin Chemical Co., Ltd. product: YP-70), bisphenol F type phenoxy group is used Except for resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.: FX-316), an anisotropic conductive film B was produced in the same manner as the anisotropic conductive film A. For the obtained anisotropic conductive film B, the ^{number of conductive particles per 25000 μm 2} was measured at 20 locations, and the average value was converted to the number of conductive particles ^{per 1 mm 2.} As a result, the density of conductive particles in the anisotropic conductive film B was 33,000 particles/mm ² .

Except for using the anisotropic conductive film B, the connection structure was produced under the conditions shown in Table 2 in the same manner as in Example 1-1, and the capture rate of conductive particles was measured. The results are shown in Table 2.

[Table 2] Comparative example 2-1 Example 2-1 Example 2-2 Average diameter of conductive particles Dp[μm] 3.3 Particle density of conductive particles [pcs/mm ² ] 33000 Adhesive layer composition Insulating adhesive layer [μm] 14 Conductive adhesive layer [μm] 3 Bump electrode configuration Area [μm ² ] 840 Height [μm] 15 Temporarily fix temperature [℃] 30 50 70 Temporarily fixed pressure [MPa] 3.3 Distance between substrate and bump electrode d[μm] 8.2 3.2 1.9 d/Dp×100[%] 248 97 58 Capture rate of conductive particles [%] 54.1 56.4 60.5

[Example 3-1 to Example 3-2, Comparative Example 3-1 to Comparative Example 3-2] The thickness of the insulating adhesive layer was changed as shown in Table 3, except that the connection structure was produced in the same manner as in Example 1-1 under the conditions shown in Table 3, and the conductive particles were measured Capture rate. The results are shown in Table 3.

[table 3] Example 3-1 Comparative example 3-1 Example 3-2 Comparative example 3-2 Average diameter of conductive particles Dp[μm] 3.3 Particle density of conductive particles [pcs/mm ² ] 28000 Adhesive layer composition Insulating adhesive layer [μm] 17 17 29 29 Conductive adhesive layer [μm] 3 Bump electrode configuration Area [μm ² ] 840 Height [μm] 15 Temporarily fix temperature [℃] 70 50 70 50 Temporarily fixed pressure [MPa] 3.3 Distance between substrate and bump electrode d[μm] 3.9 7.4 2.7 7.8 d/Dp×100[%] 118 224 82 236 Capture rate of conductive particles [%] 60.7 48.2 62.6 50.5

[Example 4-1, Comparative Example 4-1] The thickness of the insulating adhesive layer and the height of the bump electrode were changed as shown in Table 4. Except for this, the structure was connected under the conditions shown in Table 4 in the same manner as in Example 1-1. Produced and measured the capture rate of conductive particles. The results are shown in Table 4.

[Table 4] Example 4-1 Comparative example 4-1 Average diameter of conductive particles Dp[μm] 3.3 Particle density of conductive particles [pcs/mm ² ] 28000 Adhesive layer composition Insulating adhesive layer [μm] 9 14 Conductive adhesive layer [μm] 3 Bump electrode configuration Area [μm ² ] 840 Height [μm] 10 Temporarily fix temperature [℃] 50 Temporarily fixed pressure [MPa] 3.3 Distance between substrate and bump electrode d[μm] 3.4 5.8 d/Dp×100[%] 103 176 Capture rate of conductive particles [%] 57.5 53.9

[Reference example 1-1~Reference example 1-3] The thickness of the insulating adhesive layer and the conductive adhesive layer, and the particle density of the conductive particles are changed as shown in Table 5, except that they are shown in Table 5 in the same manner as in Example 1-1 The connection structure was made under the conditions of, and the capture rate of conductive particles was measured. The results are shown in Table 5. In addition, in Reference Example 1-1 to Reference Example 1-3, the average particle diameter of the conductive particles was 3.3 μm. In contrast, the thickness of the conductive adhesive layer was 5 μm. Therefore, the conductive particles did not concentrate in the different particles. To one side of the conductive film.

[table 5] Reference example 1-1 Reference example 1-2 Reference example 1-3 Average diameter of conductive particles Dp[μm] 3.3 Particle density of conductive particles [pcs/mm ² ] 55,000 Adhesive layer composition Insulating adhesive layer [μm] 12 Conductive adhesive layer [μm] 5 Bump electrode configuration Area [μm ² ] 840 Height [μm] 15 Temporarily fix temperature [℃] 30 50 70 Temporarily fixed pressure [MPa] 3.3 Distance between substrate and bump electrode d[μm] 10.9 5.4 3.9 d/Dp×100[%] 330 164 118 Capture rate of conductive particles [%] 30.5 31.0 31.4

1: Connection structure 2: electronic equipment 3: LCD panel 4: Circuit parts 5: Substrate 5a: The surface of the substrate 6: LCD display 7: Conductive particles 8: Adhesive layer 9: Anisotropic conductive film 9a: One side of anisotropic conductive film 41: body part 41a: Mounting surface 41b: Non-mounting surface 41c, 41d: long side 42: Protruding electrode 42a: Surface of protruding electrode d: The distance between the surface of the bump electrode and the surface of the substrate

Fig. 1 is a plan view showing an electronic device to which a connection structure according to an embodiment of the present invention is applied. Fig. 2 is a plan view showing the connection structure of Fig. 1. Fig. 3 is a schematic cross-sectional view showing a cross section in the direction of the arrow I-I in Fig. 2. 4(a) and 4(b) are schematic cross-sectional views showing a temporary fixing step in the method of manufacturing the connection structure of FIG. 1. Fig. 5 is an enlarged schematic cross-sectional view of the main part of Fig. 4(b). Fig. 6 is a schematic cross-sectional view showing a subsequent formal fixing step of Fig. 4(a) and Fig. 4(b).

4: Circuit parts

5: Substrate

5a: The surface of the substrate

7: Conductive particles

8: Adhesive layer

9: Anisotropic conductive film

41: body part

42: Protruding electrode

42a: Surface of protruding electrode

d: The distance between the surface of the bump electrode and the surface of the substrate

Claims (4)

A method of manufacturing a connecting structure includes a connecting step of connecting a circuit component having a protruding electrode and a substrate through an anisotropic conductive film formed by dispersing conductive particles in an adhesive layer, An anisotropic conductive film in which the conductive particles are concentrated on one side of the anisotropic conductive film is used as the anisotropic conductive film, and The connecting step includes a temporary fixing step, In the temporary fixing step, the anisotropic conductive film is arranged between the circuit component and the substrate such that the one surface side faces the substrate side, and the surface of the protruding electrode is connected to the substrate. The protruding electrode is pressed into the anisotropic conductive film so that the distance between the surfaces of the conductive particles becomes 150% or less of the average particle diameter of the conductive particles. The method for manufacturing a connected structure according to claim 1, wherein in the temporary fixing step, the distance between the surface of the protruding electrode and the surface of the substrate becomes the average particle size of the conductive particles The protruding electrode is pressed into the anisotropic conductive film so as to be 100% or less. The method for manufacturing a connected structure according to claim 1 or claim 2, wherein in the temporary fixing step, the distance between the surface of the protruding electrode and the surface of the substrate is smaller than that of the conductive particle The protruding electrode is pressed into the anisotropic conductive film in a manner of 100% of the average particle size of the film. The method for manufacturing a connected structure according to any one of claims 1 to 3, wherein the connecting step further includes a formal fixing step after the temporary fixing step, and the formal fixing step is performed by heating At the same time, the protruding electrode is further pressed into the anisotropic conductive film, and the protruding electrode and the substrate are electrically connected via the conductive particles.

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