TWI775373B - Manufacturing method of connecting structure - Google Patents

Abstract

The present invention provides a method for manufacturing a connection structure, including a connection step of dispersing a circuit component 4 having a protruding electrode 42 and a substrate 5 with anisotropic conductivity formed by dispersing conductive particles 7 in an adhesive layer 8 The anisotropic conductive film 9 is connected to the anisotropic conductive film 9, and the anisotropic conductive film in which the conductive particles 7 are concentrated on one side of the anisotropic conductive film 9 is used as the anisotropic conductive film 9, and the connection step includes a temporary fixation step that separates the anisotropic conductive film 9. The conductive film 9 is disposed between the circuit component 4 and the substrate 5 so that one surface side faces the substrate 5 side, and the distance d between the surface 42a of the protruding electrode 42 and the surface 5a of the substrate 5 is the average of the conductive particles 7 The protruding electrodes 42 are pressed into the anisotropically conductive film 9 so as to be 150% or less of the particle size.

Description

Manufacturing method of connecting structure

The present invention relates to a manufacturing method of a connecting structure.

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

In recent years, along with the development of electronic equipment, high-density wiring and high-function circuits are being advanced. As a result, reduction in the area and pitch of the protruding electrodes is being pursued. In order to obtain stable electrical connection in the connection of the protruding electrodes, a sufficient number of conductive particles need to be interposed between the protruding electrodes and the substrate.

For such a problem, for example, Patent Document 1 discloses a method for producing a bonded structure using an anisotropically conductive film whose conductive particles are present in the vicinity of one side surface of the anisotropically 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-described conventional anisotropically conductive film is used, there are cases in which the adhesive component of the anisotropically conductive film flows when heating and pressurizing is performed to manufacture a connected structure, and accordingly, the conductive The particles flow out from between the protruding electrodes and the substrate. At this time, there is a possibility that a sufficient number of conductive particles may not be interposed between the protruding electrodes and the substrate.

The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide a method for producing a connected structure in which a sufficient number of conductive particles can be interposed between a protruding electrode and a substrate. [Means of Solving Problems]

In order to solve the above-mentioned problems, the method for producing a connected structure of the present invention includes a connecting step of connecting a circuit component having a protruding electrode and a substrate through an anisotropically conductive film formed by dispersing conductive particles in an adhesive layer For connection, an anisotropically conductive film in which conductive particles are concentrated on one side of the anisotropically conductive film is used as the anisotropically conductive film, and the connecting step includes a temporary fixing step in which the anisotropically conductive film is placed on one side of the anisotropically conductive film. It is arranged between the circuit component and the substrate so that the side faces the substrate side, and the protruding electrode is pressed into the opposite direction so that the distance between the surface of the protruding 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 method for producing the bonded structure, the protruding electrodes are pressed into the anisotropically conductive film so that the distance between the surfaces of the protruding electrodes 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 excluded from between the protruding electrode and the substrate in advance. As a result, the amount of the adhesive component existing between the protruding electrodes and the substrate is reduced, so even when the adhesive component flows due to heating and pressurization in the subsequent main fixing step, the conductive particles can be prevented from self-releasing. between the protruding electrodes and the substrate. Therefore, the conductive particles can be preferably captured between the protruding electrodes and the substrate, so that in the obtained connected structure, a sufficient number of conductive particles can be interposed between the protruding electrodes and the substrate.

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

In the temporary fixing step, the protrusion electrodes can be pressed into the anisotropic conductive film so that the distance between the surface of the protrusion electrodes 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 electrodes and the substrate, so that the outflow of the conductive particles accompanying the flow of the adhesive component of the anisotropically conductive film is further suppressed, thereby further suppressing the flow of the conductive particles. The conductive particles can be further preferably captured between the protruding electrodes and the substrate.

The connecting step further includes a formal fixing step after the temporary fixing step. The formal fixing step further presses the projection electrodes into the anisotropic conductive film while heating, so as to electrically connect the projection electrodes and the substrate through the conductive particles . At this time, since the adhesive component has been removed from between the bump electrodes and the substrate in advance in the temporary fixing step, the bump electrodes are further pressed into the anisotropically conductive film while heating is performed in the main fixing step. , the conductive particles can also be suppressed from flowing out between the protruding electrodes and the substrate, so that the conductive particles can be better captured between the protruding electrodes and the substrate. Therefore, in the connection structure, a sufficient number of conductive particles can be interposed between the protruding electrodes and the substrate. [Effect of invention]

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

Hereinafter, the embodiment of the manufacturing method of the connection structure of this invention is described in detail, referring drawings.

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, for example, an electronic device 2 such as a touch panel. 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 having 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 (non-alkali glass) or the like can be used. Circuit electrodes (not shown) are formed on the surface 5 a of the substrate 5 so as to correspond to the liquid crystal display unit 6 and the protruding electrodes 42 (described later) of the circuit component 4 . The liquid crystal display unit 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, and a thickness of, for example, 0.1 mm to 0.3 mm. The circuit components 4 are arranged apart from the liquid crystal display unit 6 and are connected to circuit electrodes of the substrate 5 (details will be described later).

FIG. 2 is a plan view showing a connection structure. As shown in FIG. 2 , the circuit component 4 has a main body portion 41 and protruding electrodes 42 provided on the main body portion 41 . The main body portion 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 component 4 is arrange|positioned so that the board|substrate 5 may oppose the mounting surface 41a. A plurality of protruding electrodes (eg bump electrodes) 42 protruding from the mounting surface 41 a are formed on the main body portion 41 . As a material for forming the body portion 41 of the circuit component 4, silicon or the like can be used. The protruding electrodes 42 are formed of a material (Au or the like) that is softer than conductive particles (details will be described later) contained in the anisotropically 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, the plurality of protruding electrodes 42 are arranged in a line at substantially equal intervals, 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 of the long sides 41c is, for example, an input side electrode, and three rows of protruding electrodes 42 arranged on the other long side 41d side are, for example, an output side electrode. The protruding electrodes 42 have, for example, a height of 2 μm to 15 μm (height from the mounting surface 41 a ). In addition, on the mounting surface 41a, the plurality of protruding electrodes 42 may be arranged across, for example, two to four rows along one of the long sides 41c, and the plurality of protruding electrodes 42 may also be arranged along the other long side 41d. and, for example, two or four lines.

FIG. 3 is a schematic cross-sectional view showing a cross section in the direction of arrow I-I in FIG. 2 . As shown in FIG. 3, in the connection structure 1, the circuit component 4 and the board|substrate 5 are mutually connected via the anisotropically conductive film 9 in which the conductive particle 7 was disperse|distributed in the adhesive bond layer 8.

As an adhesive component constituting the adhesive layer 8 of the anisotropically conductive film 9, a material showing curability by heat or light can be widely used, for example, an epoxy-based adhesive or an acrylic-based adhesive can be used . A crosslinkable material can be preferably used in terms of excellent heat resistance and moisture resistance after connection. 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.

Specific examples of epoxy-based adhesives include adhesives mainly composed of high-molecular-weight epoxy resins, solid epoxy resins, or liquid epoxy resins, or those made of urethane, polymer Ester, acrylic rubber, nitrile rubber (NBR), synthetic linear polyamide, etc. These epoxy resins are modified epoxy resins. The epoxy-based adhesive usually contains the epoxy resin as a main component, and a hardener, a catalyst, a coupling agent, a filler, and the like.

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

Examples of the conductive particles 7 contained in the anisotropically conductive film 9 include particles formed of metals such as Au, Ag, Pt, Ni, Cu, W, Sb, Sn, solder, conductive carbon, and the like. The conductive particles 7 may also be coated particles in which particles made of non-conductive glass, ceramic, plastic, or the like are used as cores, and the cores are coated with the metal, conductive carbon, or the like. made. 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.

The average particle diameter of the conductive particles 7 before connection is preferably 1 μm to 18 μm, and more preferably 2 μm to 4 μm, from the viewpoint of dispersibility and conductivity. Within this range, conductive particles having an average particle diameter larger than the height of the protruding electrodes 42 are preferably used, but conductive particles having an average particle diameter of, for example, 80% to 100% of the height of the protruding electrodes 42 may be used. The average particle size of the conductive particles 7 can be obtained by measuring the particle size of 300 arbitrary conductive particles by observation using a Scanning Electron Microscope (SEM), and taking the particle size of the particles. average value. When the conductive particles 7 have protrusions or the like and are not spherical, the particle diameter of the conductive particles 7 may be the diameter of a circle circumscribing 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 connection structure of this embodiment includes a connection step including a temporary fixing step and a main fixing step. FIGS. 4( a ) and 4 ( b ) are schematic cross-sectional views showing a 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 the conductive particles 7 are concentrated on the side of one surface 9 a of the anisotropic conductive film 9 is used as the anisotropic conductive film 9 , and the anisotropic conductive film 9 is used as the anisotropic conductive film 9 . The anisotropic conductive film 9 is disposed between the circuit component 4 and the substrate 5 (on the surface 5 a of the substrate 5 ) so that the one surface 9 a of the conductive film 9 faces the substrate 5 side.

The thickness of the anisotropic conductive film 9 may be, for example, 5 μm to 30 μm. The distance that the conductive particles 7 are located only from the side of the one surface 9a of the anisotropic conductive film 9 is preferably within a range of 150% or less of the average particle size of the conductive particles 7, more preferably within a range of 130% or less, and still more preferably within a range of 110% the following range.

In the anisotropically conductive film 9, the method of making the electroconductive particle 7 exist intensively on the surface 9a side of the anisotropically conductive film 9 is not specifically limited. For example, the anisotropically conductive film in which the conductive particles 7 are concentrated on the side of the one surface 9a of the anisotropically conductive film 9 can be obtained by laminating the conductive particles 7 on the side of the insulating adhesive layer that does not contain the conductive particles 7. 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 .

The content of the conductive particles 7 in the anisotropically conductive film 9 is relative to the components 100 other than the conductive particles 7 in the anisotropically conductive film 9 from the viewpoint of preventing a short circuit caused by excessive presence of the conductive particles 7 . The volume part is preferably 1 to 100 parts by volume, more preferably 10 to 50 parts by volume. The particle density of the conductive particles 7 in the anisotropically conductive film 9 may be, for example, 5,000 particles/mm ² or more and 50,000 particles/mm ² or less.

In the temporary fixing step, then, as shown in FIG. 4( b ), by applying pressure to the opposing direction (the arrow direction in FIG. 4( b )) of the circuit component 4 and the substrate 5 while heating, the circuit is heated. The protruding electrodes 42 of the component 4 are pressed into the anisotropically conductive film 9 . The heating temperature and pressure at this time are preferably such that the adhesive component of the anisotropically conductive film 9 can flow and the conductive particles 7 can be maintained without flowing out between the protruding electrodes 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 is preferably 150% or less relative to the average particle size of the conductive particles 7, more preferably 120% or less, more preferably 100% or less, and particularly preferably less than 100%, the protruding electrodes 42 of the circuit component 4 are pressed into the anisotropically 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 main fixing step to be 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 by, for example, observing the temporarily fixed circuit component 4 and the substrate 5 from the substrate 5 side using a metal microscope, 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 following the temporary fixing step. Fig. 6 is a schematic cross-sectional view showing a main fixing step. As shown in FIG. 6 , in the main 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 heated in the opposite direction (the direction of the arrow in FIG. 6 ) at the same time. By pressing, the protruding electrodes 42 of the circuit component 4 are further pressed into the anisotropic conductive film 9 . The heating temperature and pressure at this time are equal to or higher than the heating temperature and pressure in the temporary fixing step, respectively. 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 .

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

In the method for producing the bonded structure, in the temporary fixing step, the protrusions are preliminarily fixed so that the distance d between the surface 42a of the protrusion electrode 42 and the surface 5a of the substrate 5 is equal to or less than 150% of the average particle diameter of the conductive particles. After the electrode 42 is pressed into the anisotropically conductive film 9 , in the main fixing step, the protruding electrode 42 is further pressed into the anisotropically conductive film 9 . Here, in the conventional method for producing a connected structure in which the primary fixing step is performed without the temporary fixing step, the adhesive component of the anisotropically conductive film flows at once in the primary fixing step. Therefore, there is a concern that the conductive particles flow out from between the protruding electrodes and the substrate due to the rapid flow of the adhesive component, and a sufficient number of conductive particles are not interposed between the protruding electrodes and the substrate.

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

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

In addition, in the temporary fixing step, the protruding electrodes 42 are pressed into the anisotropic direction so that the distance d between the surface 42a of the protruding electrodes 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 , so that the conductive particles 7 can be more preferably captured between the protruding electrodes 42 and the substrate 5 .

In addition, in the temporary fixing step, the protruding electrodes 42 are pressed into the anisotropic direction so that the distance d between the surfaces 42 a of the protruding electrodes 42 and the surface 5 a 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 intertwined and captured between the protruding electrodes 42 and the substrate 5 in the temporary fixing step, and therefore, the conductive particles 7 are 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 more preferably captured between the protruding electrodes 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) In a 3000 mL three-necked flask (flask) equipped with a Dimroth cooling tube, a calcium chloride tube, and a Teflon (registered trademark) stirring rod connected to a stirring motor, 4 ,4'-(9-Plenylene)-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 solution. To this, 21 g of potassium carbonate was added, and the mixture was stirred while being heated to 110°C with a mantle heater. After stirring for 3 hours, the reaction solution was added dropwise to a beaker containing 1000 mL of methanol, and the resulting precipitate was collected by suction filtration. The precipitate collected by filtration was further washed three times with 300 mL of methanol to obtain 75 g of phenoxy resin a.

Then, 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. (measurement conditions are as described above). As a result, in terms of styrene, Mn=15769, Mw=38045, and Mw/Mn=2.413.

(Preparation of Anisotropic Conductive Film A) To form the adhesive paste for the conductive adhesive layer, 50 parts by mass of bisphenol A epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd.: jER828) as an epoxy compound was prepared in terms of solid content. ), 5 parts by mass in terms of solid content of 4-hydroxyphenylmethylbenzyl perilinium hexafluoroantimonate as a hardener, and 50 parts by mass in terms of solid content of phenoxy resin as a film-forming material a. Then, as the conductive particles, a nickel layer having a thickness of 0.2 μm was provided on the surface of the styrene-cored particles to prepare conductive particles having an average particle size of 3.3 μm and a specific gravity of 2.5, and the conductive particles were prepared in an amount of 50 parts by mass. further formulated into the formulation. Then, the adhesive paste was applied to a polyethylene terephthalate (PET) film with a thickness of 50 μm using a coater and dried, thereby obtaining a film formed on PET. A layer of conductive adhesive with a thickness of 3 μm on the film.

Next, when forming the adhesive paste for insulating adhesive layers, 45 parts by mass of bisphenol F-type epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd.: jER807) as an epoxy compound was prepared in terms of solid content. , 5 parts by mass in terms of solid content of 4-hydroxyphenylmethylbenzyl perilinium hexafluoroantimonate as a hardener, and 55 parts by mass in terms of solid content of bisphenol A·bisphenol A as a film-forming material Phenol F copolymerized phenoxy resin (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.: YP-70). Then, the adhesive paste was applied 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. Then, the conductive adhesive layer and the insulating adhesive layer were heated to 40° C., and were bonded by a hot roll laminator to obtain an anisotropic conductive film A sandwiched between PET films. .

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

(Fabrication of connection structure) As a circuit component, an IC chip (chip) on which bump electrodes are arranged (outer shape 2 mm × 20 mm, thickness 0.3 mm, bump electrode area 840 μm ² (length 70 μm) was prepared. ×12 μm in width), the space between bump electrodes is 12 μm, and the height of bump electrodes is 15 μm). In addition, as a substrate, a glass substrate (Corning (Corning): #1737, 38 mm × 28 mm, thickness 0.3 mm) was prepared on the surface of the indium tin oxide (Indium Tin Oxide, ITO) formed a wiring pattern (wiring pattern). ) (pattern width is 31 μm, space between electrodes is 7 μm).

A thermocompression bonding device is used when connecting an IC chip to a glass substrate. The thermocompression bonding device includes a stage (150 mm × 150 mm) including a ceramic heater and a tool (3 mm × 20 mm). mm). Then, the PET film on the conductive adhesive layer side of the anisotropically conductive film A (2.5 mm×25 mm) was peeled off, and the conductive adhesive layer was heated and pressurized for 2 seconds under the conditions of 80° C. and 0.98 MPa, and the conductive The surface on the side of the adhesive layer is attached to the glass substrate.

Next, after aligning 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 fixing temperature and temporary fixing pressure shown in Table 1, and the bumps of the IC chip were separated. The electrode is pressed into the anisotropically conductive film A. Table 1 shows the distance between the temporarily fixed glass substrate and the bump electrodes. 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 surface of the bump electrode.

Then, heating and pressurization were performed for 5 seconds under the conditions of 160° C. and 70 MPa, whereby the IC chip was finally fixed to the glass substrate, and a connected structure was obtained. The capture rate of the conductive particles in the connected structure was calculated based on the following formula. Capture rate (%)=(number of conductive particles on bump electrode/(1 ^mm2 /bump electrode area)/number of conductive particles per 1 ^mm2 of anisotropic conductive film)×100 In addition, using a metal microscope, The number of conductive particles was actually measured at 200 locations on the bump electrode, and the average value was taken 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 Examples 1-3 Average particle diameter Dp [μm] of conductive particles 3.3 Particle density of conductive particles [pieces/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 fixed temperature [°C] 30 50 70 90 Temporary fixed pressure [MPa] 3.3 Substrate-bump electrode distance 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

[Examples 2-1 to 2-2, Comparative Example 2-1] (Preparation of anisotropically conductive film B) Instead of the phenoxy resin a, a bisphenol A type phenoxy resin (Nippon Steel & Sumitomo Metal) was used Chemical Co., Ltd.: YP-50), using bisphenol F-type phenoxy resin instead of bisphenol A and bisphenol F copolymerized phenoxy resin (Nippon Steel & Sumitomo Metal Chemical Co., Ltd.: YP-70) The anisotropically conductive film B was produced in the same manner as the anisotropically conductive film A, except for the resin (manufactured by Nippon Steel & Sumitomokin Chemical Co., Ltd.: FX-316). For the obtained anisotropically conductive film B, the number of conductive particles per 25,000 μm ² was actually measured at 20 locations, and the average value was converted into the number of conductive particles per 1 mm ² . As a result, the density of the conductive particles in the anisotropically conductive film B was 33,000 particles/mm ² .

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

[Table 2] Comparative Example 2-1 Example 2-1 Example 2-2 Average particle diameter Dp [μm] of conductive particles 3.3 Particle density of conductive particles [pieces/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 fixed temperature [°C] 30 50 70 Temporary fixed pressure [MPa] 3.3 Substrate-bump electrode distance 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] Except having changed the thickness of the insulating adhesive layer as shown in Table 3, the connection structure was produced under the conditions shown in Table 3 in the same manner as in Example 1-1, 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 particle diameter Dp [μm] of conductive particles 3.3 Particle density of conductive particles [pieces/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 fixed temperature [°C] 70 50 70 50 Temporary fixed pressure [MPa] 3.3 Substrate-bump electrode distance 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] Except that the thickness of the insulating adhesive layer and the height of the bump electrodes were changed as shown in Table 4, the connection structure was carried out in the same manner as in Example 1-1 under the conditions shown in Table 4. produced, and the capture rate of the conductive particles was measured. The results are shown in Table 4.

[Table 4] Example 4-1 Comparative Example 4-1 Average particle diameter Dp [μm] of conductive particles 3.3 Particle density of conductive particles [pieces/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 fixed temperature [°C] 50 Temporary fixed pressure [MPa] 3.3 Substrate-bump electrode distance d[μm] 3.4 5.8 d/Dp×100[%] 103 176 Capture rate of conductive particles [%] 57.5 53.9

[Reference Example 1-1 to Reference Example 1-3] Except having changed the thicknesses of the insulating adhesive layer and the conductive adhesive layer, and the particle density of the conductive particles as shown in Table 5, the same procedure as in Example 1-1 was performed as shown in Table 5. The connection structure was fabricated under the same conditions, and the capture rate of the 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, whereas the thickness of the conductive adhesive layer was 5 μm, so the conductive particles were not concentrated in the toward one side of the conductive film.

[table 5] Reference Example 1-1 Reference Example 1-2 Reference Example 1-3 Average particle diameter Dp [μm] of conductive particles 3.3 Particle density of conductive particles [pieces/mm ² ] 55000 Adhesive layer composition Insulating adhesive layer [μm] 12 Conductive adhesive layer [μm] 5 Bump electrode configuration Area [μm ² ] 840 Height [μm] 15 Temporarily fixed temperature [°C] 30 50 70 Temporary fixed pressure [MPa] 3.3 Substrate-bump electrode distance 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: Connect the structure 2: Electronic equipment 3: LCD panel 4: Circuit Parts 5: Substrate 5a: Surface of the substrate 6: LCD display 7: Conductive particles 8: Adhesive layer 9: Anisotropic conductive film 9a: One side of anisotropically conductive film 41: body part 41a: Mounting surface 41b: Non-mounting surface 41c, 41d: Long side 42: Protruding electrode 42a: Surface of the protruding electrode d: distance between the surface of the protruding 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 arrow I-I in FIG. 2 . FIGS. 4( a ) and 4( b ) are schematic cross-sectional views showing a temporary fixing step in the method of manufacturing the connected 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 main fixing step subsequent to Fig. 4(a) and Fig. 4(b) .

4: Circuit Parts

5: Substrate

5a: Surface of the substrate

7: Conductive particles

8: Adhesive layer

9: Anisotropic conductive film

41: body part

42: Protruding electrode

42a: Surface of the protruding electrode

d: distance between the surface of the protruding electrode and the surface of the substrate

Claims (4)

A method for producing a connection structure, comprising a connection step of connecting a circuit component having a protruding electrode and a substrate via an anisotropic conductive film in which conductive particles are dispersed in an adhesive layer, using the Anisotropically conductive particles in which the conductive particles are concentrated on one side of the anisotropically conductive film and the particle density of the conductive particles in the anisotropically conductive film is 5,000 particles/mm ² or more and 50,000 particles/mm ² or less The anisotropic conductive film is used as the anisotropically conductive film, and the connecting step includes a temporary fixing step of disposing the anisotropically conductive film on the substrate with the one surface side facing the substrate side. Between the circuit component and the substrate, the protruding electrode is pressed into the area so that the distance between the surface of the protruding electrode and the surface of the substrate becomes 150% or less of the average particle diameter of the conductive particles. in the anisotropic conductive film. The method for producing 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 is equal to the average particle diameter of the conductive particles The protruding electrode is pressed into the anisotropic conductive film so as to be 100% or less. The method for producing 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 is smaller than the average particle diameter of the conductive particles The protruding electrodes are pressed into the anisotropic conductive film in a 100% manner. The manufacturing method of a connected structure according to any one of claim 1 to claim 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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