HK1150322B - Connecting film, and joined structure and method for producing the same - Google Patents

Abstract

A connecting film which electrically connects a first circuit member with a second circuit member having a nitrogen atom-containing film on a surface thereof facing the first circuit member, the connecting film including a first layer which is to be located at the first circuit member side, and a second layer which is to be located at the second circuit member side, wherein the first layer contains a cationic curing agent and an epoxy resin, and the second layer contains a radical curing agent, an acrylic resin and an epoxy compound , wherein one of the first layer and the second layer is a conductive particle-containing organic resin layer, and the other layer is an insulating organic resin layer containning no conductive particles, and wherein the minimum melt viscosity of the conductive particle-containing organic resin layer is ten times or more greater than that of the insulating orgainc resin layer.

Description

Connecting film, bonded body, and method for producing same

Technical Field

The present invention relates to a connection film, a bonded body, and a method for manufacturing the bonded body, and more particularly, to a connection film capable of electrically and mechanically connecting circuit elements such as an IC chip and a liquid crystal panel (LCD panel) in a Liquid Crystal Display (LCD), a bonded body having the connection film, and a method for manufacturing the bonded body.

Background

Conventionally, as a method for connecting circuit elements, a tape-shaped connecting material (for example, Anisotropic Conductive Film (ACF)) in which a thermosetting resin in which Conductive particles are dispersed is applied to a separation Film has been used.

Such an anisotropic conductive film (connection film) is used for electrically connecting terminals of a Flexible Printed Circuit (FPC) or an IC chip to ito (indium Tin oxide) electrodes formed on a glass substrate of an LCD panel while bonding the terminals.

As the connection film, a cation curing connection film containing a cation curing agent and an epoxy resin has been put to practical use, and low-temperature curability and reduced curling of an adherend have been achieved.

However, since a cationic curing agent such as a sulfonium salt has high curing activity, even a trace amount of impurities or the like easily inhibit the curing reaction, resulting in problems such as poor curing.

In particular, poor curing due to a passivation film made of polyimide formed on the back surface of the IC chip often occurs. This is because when an IC chip is connected to a cationic curable adhesive film, the cationic curable adhesive film is stuck to the IC chip, and a cation (H) is generated at the beginning of the curing reaction⁺) It is deactivated by the polyimide material of the passivation film. Generated cation (H)⁺) The reason why the polyimide material of the passivation film is deactivated is considered to be a cation (H)⁺) Reacts with nitrogen (N) atoms in the polyimide to be trapped (R is generated)₃N→R₃N⁺H to form an ammonium salt).

Further, even when TAB in which polyimide and copper foil are bonded with an adhesive is used for connection, there is a problem that curing is inhibited because the adhesive is made of polyamide.

In addition, as the connection film, a radical curing type connection film containing a radical curing agent (organic peroxide) and an acrylic resin has been put into practical use in many cases for connection on the wiring board (PWB) side, and low-temperature curability has been achieved. However, since the radical-curable binder film does not generate hydroxyl groups during curing, the interaction with the polar adherend is weakened, and problems such as weakening of adhesive strength and poor curing occur. In particular, the adhesion of the radical curing type connecting film to the glass surface of the LCD panel is poor, and the interface separation problem is likely to occur on the LCD panel side.

Radical curing type connection films containing epoxy resins have also been disclosed (for example, patent document 1), but the adhesion to glass is not sufficient in this case.

Therefore, the radical curing type connection film is not suitable for connection on the LCD panel side, and has not yet achieved practical results.

Further, a rubber-based material generally used as a material of the connection film tends to cause a problem of inhibition of curing.

Further, a 2-membered curing type adhesive film in which a radical curing agent (low-temperature curing) and an imidazole curing agent (high-temperature curing) are mixed has also been proposed (for example, patent document 2). However, since a connection film formed by mixing components having different curing mechanisms is subject to layer separation during curing, internal cracks are likely to occur, and connection reliability is poor. Further, curing needs to be performed in 2 stages, and is not suitable for short-time connection.

Further, there have been proposed a 2-membered curing type connection film in which a radical curing agent and a cationic curing agent are mixed (for example, patent document 3), a connection film in which a thermosetting composition and a photocurable composition are contained in a binder (for example, patent document 4), and a connection film having a 2-layer structure including a cationic photocurable layer and a radical photocurable layer (for example, patent document 5), but these have not improved curing failure due to a passivation film made of polyimide formed on the back surface of an IC chip. Therefore, it is desired to develop a connection film that does not cause poor curing due to a passivation film made of polyimide.

In recent years, in display devices such as LCDs, PDPs, and organic ELs, metal wirings such as Al, Mo, Cr, Ti, Cu, and Ni are often deposited on a substrate such as ITO from the viewpoint of electrical conductivity. These metal wirings are poor in light permeability, and therefore it is difficult to cure the connection film by photocuring to connect the circuit elements.

In addition, a method is known in which a difference in viscosity between the 1 st layer and the 2 nd layer is provided in a 2-layer connection film to improve the efficiency of conductive particle replenishment (for example, patent document 6). However, in this connection film, the bonding force near the boundary between the 1 st layer and the 2 nd layer may be weakened, and the conduction reliability may be lowered.

Further, a method of improving adhesiveness by using a hydroxyl group-containing resin such as a phenoxy resin is known (for example, patent document 7). However, the adhesive disclosed in patent document 7 does not have a 2-layer structure having different viscosities, and is completely different in structure and effect from the adhesive of the present invention.

Documents of the prior art

Patent document 1: japanese patent No. 3587859

Patent document 2: japanese patent laid-open publication No. 2007-262412

Patent document 3: japanese patent laid-open publication No. 2006-127776

Patent document 4: japanese patent laid-open publication No. 2005-235956

Patent document 5: international publication No. 00/084193

Patent document 6: japanese laid-open patent publication No. 6-45024

Patent document 7: international publication No. 00/046315

Disclosure of Invention

Technical problem to be solved by the invention

The present invention has been made to solve the above-described conventional problems and to achieve the following object. That is, an object of the present invention is to provide a connection film excellent in both replenishment efficiency of conductive particles and conduction reliability, and a joined body and a method for producing the same.

Means for solving the problems

The means for solving the above problems are as follows. Namely:

<1> a connection film for electrically connecting a 1 st circuit element and a2 nd circuit element, wherein the 2 nd circuit element has a film containing nitrogen atoms formed on a surface facing the 1 st circuit element, the connection film having a 1 st layer on the 1 st circuit element side and a2 nd layer on the 2 nd circuit element side; the layer 1 contains a cationic curing agent and an epoxy resin; the 2 nd layer contains a radical curing agent, an acrylic resin and an epoxy compound; any one of the 1 st and 2 nd layers is a conductive particle-containing organic resin layer containing conductive particles; the other of the 1 st and 2 nd layers is an insulating organic resin layer having no conductivity; the minimum melt viscosity of the conductive particle-containing organic resin layer is 10 times or more the minimum melt viscosity of the insulating organic resin layer.

In the connection film described in <1>, the 1 st layer containing a cationic curing agent and an epoxy resin is provided on the 1 st circuit element side, the 2 nd layer containing a radical curing agent and an acrylic resin is provided on the 2 nd circuit element side, and the 2 nd circuit element has a film containing a nitrogen atom on a surface facing the 1 st circuit element, so that the adhesive strength to the circuit element can be improved.

Further, since the minimum melt viscosity of the conductive particle-containing organic resin layer is 10 times or more the minimum melt viscosity of the insulating organic resin layer, the efficiency of replenishing the conductive particles can be improved. Thereby being capable of coping with Fine Pitch (Fine Pitch) connection.

Here, in the connection film having a 2-layer structure with a difference in viscosity, it is difficult to maintain the mixed state of the layers at the time of pressure bonding, and the layers tend to be separated from each other and the bonding force between the layers tends to be weak. In contrast, in the present invention, since the epoxy compound contained in the 2 nd layer reacts with the epoxy resin contained in the 1 st layer, the bonding force between the 1 st layer and the 2 nd layer can be improved.

<2> the connection film of <1> above, wherein the epoxy compound has a molecular weight of 900 to 50000; the epoxy equivalent is 450 or more and 5000 or less.

<3> the connecting film of <1> or <2> above, wherein the 2 nd layer contains a hydroxyl group-containing acrylate.

<4> a bonded body, comprising a 1 st circuit element, a2 nd circuit element, and the connection film of any one of <1> to <3>, wherein the 2 nd circuit element has a film containing a nitrogen atom formed on a surface facing the 1 st circuit element.

In the joined body described in <4>, the 1 st layer containing the cationic curing agent and the epoxy resin is provided on the 1 st circuit element side, the 2 nd layer containing the radical curing agent and the acrylic resin is provided on the 2 nd circuit element side, and the 2 nd circuit element has a film containing a nitrogen atom on a surface facing the 1 st circuit element, so that the adhesive strength to the circuit element can be improved.

In addition, since the epoxy compound contained in the 2 nd layer reacts with the epoxy resin contained in the 1 st layer at the time of bonding, the bonding force between the 1 st layer and the 2 nd layer can be improved.

Further, since the minimum melt viscosity of the conductive particle-containing organic resin layer is 10 times or more the minimum melt viscosity of the insulating organic resin layer, the replenishment efficiency of the conductive particles can be improved.

<5> a method for manufacturing a bonded body, comprising a connecting step of connecting the 1 st and 2 nd circuit elements by heating and pressure bonding with the connecting film described in any one of <1> to <3 >.

In the method of manufacturing a joined body described in <5>, the 1 st and 2 nd circuit elements can be connected by pressure bonding while heating by the connection film described in any one of <1> to <3> in the connection step, and therefore a connection film excellent in both replenishment efficiency of conductive particles and conduction reliability can be manufactured.

<6> the method of manufacturing a bonded body according to <5>, wherein the 1 st circuit element is an LCD panel; the 2 nd circuit element is any one of IC and TAB, and has a polyimide film; in the connection step, the 1 st layer is pre-attached to the LCD panel, the polyimide is pre-attached to the 2 nd layer, and the 2 nd circuit element is pressure-bonded by hot pressing.

Effects of the invention

The present invention can solve the above-described problems of the related art, achieve the above object, and provide a connection film excellent in both replenishment efficiency of conductive particles and conduction reliability, a bonded body, and a method for producing the same.

Drawings

FIG. 1 is a schematic view of a joined body of the present invention.

FIG. 2 is a schematic view of a connecting film of the present invention.

Fig. 3 is a schematic diagram of a method for evaluating adhesive strength.

Description of the labeling:

10: LCD panel (1 st circuit element), 11: IC chip (2 nd circuit element), 11 a: terminal, 12: connection film, 12 a: conductive particles, 20: separation layer (separator), 21: conductive particle-containing organic resin layer, 22: insulating organic resin layer, 100: a junction body is provided.

Detailed Description

Bonded body

The present invention provides a bonded body, which comprises a 1 st circuit element, a2 nd circuit element and a connection film; further, there are other elements appropriately selected as needed.

For example, as shown in fig. 1, the joined body 100 includes an LCD panel 10 as a 1 st circuit element, an IC chip 11 as a2 nd circuit element, and a connection film 12. The terminals 11a of the IC chip 11, the conductive particles 12a of the connection film 12, and the terminals (not shown) of the LCD panel 10 are electrically connected to each other, whereby the LCD panel 10 and the IC chip 11 are electrically connected to each other.

<1 st Circuit element >

The 1 st circuit element is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include a glass LCD substrate (LCD panel), a glass PDP substrate (PDP panel), and a glass organic EL substrate (organic EL panel).

Also, the 1 st circuit element has a metal wiring made of, for example, aluminum. As described above, if the 1 st circuit element has a wiring made of a light-impermeable material such as aluminum, it is difficult to photocure the resin contained in the connection film, and therefore the resin contained in the connection film is more preferably a thermosetting resin.

<2 nd Circuit element >

The 2 nd circuit element is not particularly limited as long as it is a film containing nitrogen atoms formed on the surface facing the 1 st circuit element, and may be appropriately selected according to the purpose, for example, an IC chip on which a passivation film containing polyimide is formed, an IC chip on which a passivation film containing Si is formed, or the like₃N₄An IC chip with a passivation film, a TAB tape with an IC chip mounted thereon, and the like.

The 2 nd circuit element may be made of a material which does not transmit light. As described above, if the 2 nd circuit element is made of a material which does not transmit light, it is difficult to photocure the resin contained in the connection film, and therefore, the resin contained in the connection film is more preferably a thermosetting resin.

< connecting film >

The connection film has a 1 st layer and a2 nd layer, and further has other layers appropriately selected as needed. Either one of the 1 st and 2 nd layers is a conductive particle-containing organic resin layer containing conductive particles, and the other one of the 1 st and 2 nd layers is an insulating organic resin layer having no conductivity.

For example, as shown in fig. 2, the connection film 12 includes a separation layer (separator)20, an insulating organic resin layer 22 as a2 nd layer formed on the separation layer (separator)20, and a conductive particle-containing organic resin layer 21 as a 1 st layer formed on the insulating organic resin layer 22.

The connection film 12 is formed by, for example, attaching the conductive particle-containing organic resin layer 21 to the LC panel 10 (fig. 1) side. Then, the separation layer (separator)20 is peeled off, and the IC chip 11 (fig. 1) is pressure-bonded from the insulating organic resin layer 22 side, thereby forming the joined body 100 (fig. 1).

< layer 1>

The 1 st layer, which is provided on the 1 st circuit element side, is not particularly limited as long as it contains a cationic curing agent and an epoxy resin, and may be appropriately selected according to the purpose.

The 1 st layer is preferably a conductive particle-containing organic resin layer containing conductive particles. In this case, the following 2 nd layer must be an insulating organic resin layer having no conductivity.

< cationic curing agent > >)

The cationic curing agent is not particularly limited and may be appropriately selected according to the purpose, and may be, for example, a sulfonium salt, an onium salt, or the like, and among them, an aromatic sulfonium salt is preferable.

< epoxy resin > >)

The epoxy resin is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include thermosetting epoxy resins such as bisphenol a type epoxy resin, bisphenol F type epoxy resin, phenol novolac epoxy resin, and modified epoxy resins thereof. It may be used alone in 1 kind, or in combination of 2 or more kinds.

< conductive particles > >)

The conductive particles are not particularly limited, and those conventionally used for anisotropic conductive adhesives (connection films) can be used, and for example, metal particles or metal-coated resin particles having a particle diameter of 1 to 50 μm can be used.

Examples of the metal particles include nickel, cobalt, and copper. In order to prevent oxidation of the surface, particles coated with gold or palladium on the surface may be used. Further, particles having metal protrusions or an insulating film made of an organic material on the surface thereof may be used.

The metal-coated resin particles are, for example, spherical particles plated with 1 or more kinds of nickel, cobalt, copper, or the like. Similarly, particles coated with gold or palladium on the outermost surface may also be used. Further, particles having metal protrusions or an insulating film made of an organic material on the surface thereof may be used.

< layer 2>

The 2 nd layer is provided on the 2 nd circuit element side, and is not particularly limited as long as it contains a radical curing agent, an acrylic resin, and an epoxy compound, and may be appropriately selected according to the purpose.

The 2 nd layer preferably contains a hydroxyl group-containing acrylate from the viewpoint of adhesiveness to a polar circuit element.

The 2 nd layer is preferably an insulating organic resin layer having no conductivity, but may be a conductive particle-containing organic resin layer containing the conductive particles. In this case, the 1 st layer must be an insulating organic resin layer.

< free radical curing agent > >)

The radical curing agent is not particularly limited and may be appropriately selected according to the purpose, and may be, for example, an organic peroxide.

< < acrylic resin > >)

The acrylic resin is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include acrylic resins such as methacrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, dimethylol tricyclodecane diacrylate, tetramethylene glycol tetraacrylate, 2-hydroxy-1, 3-diacryloyloxypropane, 2-bis [4- (acryloyloxymethyl) phenyl ] propane, 2-bis [4- (acryloyloxyethoxy) phenyl ] propane, dicyclopentenyl acrylate, tricyclodecyl acrylate, tris (acryloyloxyethyl) isocyanurate, and urethane acrylate. It may be used alone in 1 kind, or in combination of 2 or more kinds.

The acrylic ester may be methyl acrylate, and 1 kind of the acrylic ester may be used alone, or 2 or more kinds may be used in combination.

< epoxy Compound > >)

The epoxy compound is not particularly limited and may be appropriately selected according to the purpose, and is, for example, the same as the epoxy resin.

The epoxy compound contained in the 2 nd layer reacts with the epoxy resin contained in the 1 st layer at the time of pressure bonding. Therefore, a mixed layer in which both radical curing by an acrylic resin and cationic curing by an epoxy compound occur simultaneously is formed in the 1 st layer side portion of the 2 nd layer, and the bonding force between the 1 st layer and the 2 nd layer can be significantly improved by this mixed layer.

The molecular weight of the epoxy compound is preferably 900 to 50000, more preferably 5000 to 40000, and particularly preferably 10000 to 30000.

When the molecular weight of the epoxy compound is less than 900, the unreacted epoxy compound is not included in the cured mesh (network) of the layer 2, and thus the adhesive strength on the layer 2 side may be reduced. When the molecular weight of the epoxy compound exceeds 50000, the viscosity increases and the particle capturing rate decreases.

The epoxy equivalent of the epoxy compound is preferably 450 to 5000, more preferably 1000 to 4500, and particularly preferably 2000 to 4000.

When the epoxy equivalent of the epoxy compound is less than 450, the epoxy compound is a compound having a small molecular weight and is not contained in the mesh of the 2 nd layer, and the remaining unreacted epoxy group causes a reduction in the life of the film; when the amount exceeds 5000, the amount of epoxy groups is too small, the reaction with the epoxy resin of the layer 1 is also reduced, and the interlayer bonding force cannot be sufficiently increased.

< hydroxyl group-containing acrylate > >)

The hydroxyl group-containing acrylate is not particularly limited as long as it has 1 or more hydroxyl groups in the molecule, and may be appropriately selected according to the purpose.

The acid value of the hydroxyl group-containing acrylate is preferably 1mgKOH/g or more and 360mgKOH/g or less, more preferably 10mgKOH/g or more and 300mgKOH/g or less, and particularly preferably 50mgKOH/g or more and 250mgKOH/g or less.

When the acid value of the hydroxyl-containing acrylate is less than 1mgKOH/g, the adhesive strength is lowered; when the amount exceeds 360mgKOH/g, the electrode may be corroded, which is not preferable.

< minimum melt viscosity ratio >)

The minimum melt viscosity of the conductive particle-containing organic resin layer is preferably 10 times or more, and more preferably 13 times or more, the minimum melt viscosity of the insulating organic resin layer.

When the minimum melt viscosity of the conductive particle-containing organic resin layer is 10 times less than the minimum melt viscosity of the insulating organic resin layer, the replenishment efficiency of the conductive particles cannot be sufficiently improved.

In view of conductivity, the minimum melt viscosity of the conductive particle-containing organic resin layer is preferably 1000 times or less the minimum melt viscosity of the insulating organic resin layer.

< other layers >

The other layer is not particularly limited and may be appropriately selected according to the purpose, and may be, for example, a separate layer.

The shape, structure, size, thickness, material (material), and the like of the separation layer are not particularly limited and may be appropriately selected according to the purpose, but a separation layer having good separability or high heat resistance is preferable, and for example, a transparent separation PET (polyethylene terephthalate) film coated with a separating agent such as silicone resin is suitably used. In addition, PTFE (polytetrafluoroethylene) membranes can also be used.

< other ingredients >

The other component is not particularly limited and may be appropriately selected according to the purpose, and for example, a silane coupling agent, a surfactant, or the like may be used.

Method for manufacturing bonded body

The method for manufacturing a joined body of the present invention includes at least a joining step and other steps appropriately selected as necessary.

< connecting Process >

The connecting step is a step of connecting the 1 st and 2 nd circuit elements by pressure bonding while heating through the connecting film of the present invention.

The heating is determined by the total heat quantity, and is carried out at a heating temperature of 120-220 ℃ under the condition that the connection is completed within 10 seconds.

The pressure welding is different according to the type of the 2 nd circuit element, and the pressure is 2-6 MPa when the TAB tape is used; when the IC chip is used, the pressure is 20-120 MPa, and the processes are respectively carried out for 3-10 seconds.

Further, the connection may be performed by ultrasonic waves or heat.

Here, when the 1 st circuit element is any one of an LCD panel and the 2 nd circuit element is an IC chip and TAB and has a polyimide film, in the connection step, it is preferable that the 1 st layer is pre-attached to be connected to the LCD panel, the polyimide film is pre-set to be connected to the 2 nd layer, and then the 2 nd circuit element side is pressure-bonded by using a hot press.

Since the 2 nd circuit element is pressed from the 2 nd circuit element side as described above, the 2 nd circuit element is brought into contact with the hot press, and the resin of the 2 nd layer is heated to lower the melt viscosity thereof and facilitate the flow thereof, whereby the conductive particles of the 1 st layer can be efficiently captured.

The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Production example 1: cation-curable electrode-bonding film C1

Conductive particles (trade name: AUL704, manufactured by WATERCHEMICAL INDUSTRIAL Co., Ltd.) were dispersed in a dispersion composed of 50 parts of phenoxy resin (trade name: YP-50, manufactured by Tokyo Chemicals Co., Ltd.), 35 parts of Epoxy resin (trade name: jER828, manufactured by Japan Epoxy Resins (ジヤパンエポキシレジン Co., Ltd.), 1 part of silane coupling agent (trade name: KBM-403, manufactured by shin-Etsu Silicone Co., Ltd.), 4 parts of curing agent (trade name: SI-60L, manufactured by Sanxin chemical industries Co., Ltd.), and 10 parts of silica microparticles (trade name: AEROSIL RY200, Japan ae, manufactured by Japan)rosil corporation) until the particle density is 30000 particles/mm²A cation-curable electrode-bonding film C1 having a thickness of 10 μm was prepared.

Specifically, first, the above raw materials were prepared into a mixed solution containing ethyl acetate and toluene at a solid content of 50%. Then, the mixed solution was coated on a PET film having a thickness of 50 μm, and then dried in an oven at 80 ℃ for 5 minutes, to obtain a cation-curable electrode bonding film C1.

The minimum melt viscosity was measured by a rheometer (trade name: RS 150, manufactured by HAAKE). The measurement was carried out at a temperature rise rate of 10 ℃/min.

Production example 2: cation-curable electrode-bonding film C2

A cationically curable electrode bonding film C2 was prepared in the same manner as in production example 1, except that the amount of phenoxy resin (trade name: YP-50, manufactured by Tokyo chemical Co., Ltd.) was changed from 50 parts to 60 parts in production example 1, and no silica fine particles (trade name: AEROSIL RY200, manufactured by Nippon AEROSIL Co., Ltd.) were added, and the minimum melt viscosity was measured.

Production example 3: cation-curable electrode-bonding film C3

A cation-curable electrode bonding film C3 was produced in the same manner as in production example 1, except that the amount of Epoxy resin (trade name: jER828, manufactured by Japan Epoxy Resins) added in production example 1 was changed from 35 parts to 30 parts, and 5 parts of acrylic resin (trade name: EB600, manufactured by daicel-cytec) was added, and the minimum melt viscosity was measured.

Production example 4: cation-curable electrode-bonding film C4

A cationic electrode-binding film C4 was produced in the same manner as in production example 1, except that no silica fine particles (trade name: AEROSIL RY200, manufactured by JEOLOSIL CORPORATION) were added in production example 1, and the lowest melt viscosity was measured.

The compositions and the minimum melt viscosities of the cationically curable electrode bonding films C1 to C4 are shown in table 1 below.

TABLE 1

Production example 5: radical curing type electrode bonding film R1

A film R1 for radical-curable electrode adhesive having a thickness of 10 μm was prepared from 50 parts of phenoxy resin (trade name: YP-50, manufactured by Tokyo chemical Co., Ltd.), 35 parts of acrylic resin (trade name: EB-600, manufactured by daicel-cytec Co., Ltd.), 10 parts of Epoxy compound (trade name: jER1001, manufactured by Japan Epoxy Resins Co., Ltd.), 1 part of silane coupling agent (trade name: KBM-503, manufactured by shin-Etsu Silicone Co., Ltd.), and 4 parts of curing agent (NYPER BW, manufactured by Japan fat and oil Co., Ltd.).

Specifically, first, the above raw materials were prepared into a mixed solution containing ethyl acetate and toluene at a solid content of 50%. Then, the mixed solution was coated on a PET film having a thickness of 50 μm, and then dried in an oven at 80 ℃ for 5 minutes, to obtain a radical curing type electrode bonding film R1.

The minimum melt viscosity was measured by a rheometer (trade name: RS 150, manufactured by HAAKE). The measurement was carried out at a temperature rise rate of 10 ℃/min.

Production example 6: radical curing type electrode bonding film R2

A free-radically curable electrode-bonding film R2 was prepared in the same manner as in production example 5, except that 10 parts of an Epoxy compound (trade name: jER1010, manufactured by Japan Epoxy Resins) was added instead of 10 parts of the Epoxy compound (trade name: jER1001, manufactured by Japan Epoxy Resins), and the minimum melt viscosity was measured.

Production example 7: radical curing type electrode bonding film R3

A free-radically curable electrode bonding film R3 was produced in the same manner as in production example 5 except that 10 parts of an Epoxy compound (trade name: jER4110, manufactured by Japan Epoxy Resins) was added in place of 10 parts of the Epoxy compound (trade name: jER1001, manufactured by Japan Epoxy Resins), and the minimum melt viscosity was measured.

Production example 8: radical curing type electrode bonding film R4

A radical curing electrode bonding film R4 was prepared and the lowest melt viscosity was measured in the same manner as in production example 7, except that the amount of acrylic resin (trade name: EB-600, manufactured by daicel-cytec) added in production example 7 was changed from 35 parts to 30 parts, and 5 parts of a hydroxyl group-containing acrylate (trade name: Nk-ester CB-1, manufactured by Xinzhou chemical Co., Ltd.).

Production example 9: radical curing type electrode bonding film R5

A radical curing electrode bonding film R5 was prepared in the same manner as in production example 5 except that 10 parts of an Epoxy compound (trade name: jER828, manufactured by Japan Epoxy Resins) was added instead of 10 parts of the Epoxy compound (trade name: jER1001, manufactured by Japan Epoxy Resins) in production example 5, and the minimum melt viscosity was measured.

Production example 10: radical curing type electrode bonding film R6

A radical curing electrode bonding R6 was prepared in the same manner as in production example 5 except that 10 parts of an Epoxy compound (trade name: YR55, manufactured by Tokyo chemical Co., Ltd.) was added instead of 10 parts of the Epoxy compound (trade name: jER1001, manufactured by Japan Epoxy Resins Co., Ltd.) in production example 5, and the minimum melt viscosity was measured.

Production example 11: radical curing type electrode bonding film R7

A free-radically curable electrode bonding film R7 was prepared in the same manner as in production example 5, except that the amount of phenoxy resin (trade name: YP-50, manufactured by Tokyo chemical Co., Ltd.) was changed from 50 parts to 60 parts in production example 5, and 10 parts of Epoxy compound (trade name: jER1001, manufactured by Japan Epoxy Resins Co., Ltd.) was not added, and the minimum melt viscosity was measured.

Production example 12: radical curing type electrode bonding film R8

A radically curable electrode bonding film R8 was produced in the same manner as in production example 8 except that the amount of acrylic resin (trade name: EB-600, manufactured by daicel-cytec) added in production example 8 was changed from 30 parts to 35 parts, the amount of hydroxyl group-containing acrylate (trade name: Nk-ester CB-1, manufactured by Newzhongcun chemical) added was changed from 5 parts to 10 parts, and 10 parts of an Epoxy compound (trade name: JeR4110, manufactured by Japan Epoxy Resins) was not added, and the lowest melt viscosity was measured.

The hydroxyl group-containing acrylate (trade name: Nk-ester CB-1, manufactured by Newzhongcun chemical Co., Ltd.) had an acid value of 197 mgKOH/g.

Production example 13: radical curing type electrode bonding film R9

A free-radically curable electrode-bonding film R9 was prepared in the same manner as in production example 12, except that 10 parts of a hydroxyl-containing acrylate (trade name: β -CEA, manufactured by daicel-cytec Co., Ltd.) was added instead of 10 parts of a hydroxyl-containing acrylate (trade name: Nk-ester CB-1, manufactured by Newzhongcun chemical Co., Ltd.) in production example 12, and the minimum melt viscosity was measured.

The hydroxyl group-containing acrylate (trade name: β -CEA, manufactured by daicel-cytec) had an acid value of 365 mgKOH/g.

Production example 14: radical curing type electrode bonding film R10

A radically curable electrode bonding film R10 was prepared in the same manner as in production example 12 except that the amount of phenoxy resin (trade name: YP-50, manufactured by Tokyo chemical Co., Ltd.) added in production example 12 was changed from 50 parts to 55 parts, and 5 parts of phosphate acrylate (trade name: LIGHT-ESTER P-1M, manufactured by Kyowa chemical Co., Ltd.) was added in place of 10 parts of hydroxyl-containing acrylate (trade name: Nk-ESTER CB-1, manufactured by Newzhonghama chemical Co., Ltd.), and the lowest melt viscosity was measured.

Production example 15: radical curing type electrode bonding film R11

A free-radically curable electrode bonding film R11 was prepared and the lowest melt viscosity was measured in the same manner as in production example 12, except that 10 parts of urethane acrylate (trade name: U-2PPA, manufactured by Newzhongcun chemical Co., Ltd.) was added in place of 10 parts of hydroxyl group-containing acrylate (trade name: Nk-ester CB-1, manufactured by Newzhongcun chemical Co., Ltd.) in production example 12.

The compositions and the minimum melt viscosities of the radically curable electrode bonding films R1 to R11 are shown in table 2 below. The epoxy equivalent and molecular weight of the partial materials are shown in table 3 below.

TABLE 3

	Epoxy equivalent	Molecular weight
			YP55	10000～20000	50000～60000
jER828	184～194	370
			jER1001	450～500	900
jER1010	3000～5000	5500
			jER4110	3500～4000	About 5 ten thousand
EB-600	-	600

Example 1

The cation-curable electrode bonding film C1 produced in production example 1 and the radical-curable electrode bonding film R1 produced in production example 5 were laminated to form a 2-layer electrode bonding film, and an IC chip (size: 1.8 mm. times.20.0 mm; thickness: 0.5 mm; gold bump size: 30 μm. times.85 μm; bump height: 15 μm; bump pitch: 50 μm) and an aluminum-patterned glass substrate (product name: 1737F, manufactured by Corning Ltd., size: 50 mm. times.30 mm. times.0.5 mm) corresponding to the pattern of the IC chip were connected to each other through the 2-layer electrode bonding film to form a joined body.

Further, a radical curing type electrode bonding film R1 was attached to the IC chip side, and a cation curing type electrode bonding film C1 was attached to the aluminum textured glass substrate side. Further, polyimide may be used as the passivation film of the IC chip. The connection between the IC chip and the patterned aluminum glass substrate was performed by pressing the IC chip at 180 ℃ under 80MPa for 5 seconds.

Example 2

A joined body was produced in the same manner as in example 1, except that the radical-curing electrode bonding film R1 was replaced with the radical-curing electrode bonding film R2 produced in production example 6 in example 1.

Example 3

A joined body was produced in the same manner as in example 1, except that the radical-curing electrode bonding film R1 was replaced with the radical-curing electrode bonding film R3 produced in production example 7 in example 1.

Example 4

A joined body was produced in the same manner as in example 1, except that the radical-curing electrode bonding film R1 was replaced with the radical-curing electrode bonding film R4 produced in production example 8 in example 1.

Example 5

A joined body was produced in the same manner as in example 1, except that the radical-curing electrode bonding film R1 was replaced with the radical-curing electrode bonding film R5 produced in production example 9 in example 1.

Example 6

A joined body was produced in the same manner as in example 1, except that the radical-curing electrode bonding film R1 was replaced with the radical-curing electrode bonding film R6 produced in production example 10 in example 1.

Comparative example 1

A joined body was produced in the same manner as in example 1, except that the cation-curable electrode bonding film C2 produced in production example 2 was used in place of the cation-curable electrode bonding film C1 in example 1, and the radical-curable electrode bonding film R7 produced in production example 11 was used in place of the radical-curable electrode bonding film R1.

Comparative example 2

A joined body was produced in the same manner as in comparative example 1, except that the cation-curable electrode bonding film C3 produced in production example 3 was used in place of the cation-curable electrode bonding film C2 in comparative example 1.

Comparative example 3

A joined body was produced in the same manner as in comparative example 1, except that in comparative example 1, the radical-curing electrode bonding film R2 produced in production example 6 was used in place of the radical-curing electrode bonding film R7.

Evaluation of bonded body

The bonded bodies produced in examples 1 to 6 and comparative examples 1 to 3 were evaluated by the following methods.

< minimum melt viscosity ratio >

The ratio of the lowest melt viscosity of the conductive particle-containing organic resin layer (ACF) to the lowest melt viscosity of the insulating organic resin layer (NCF) was calculated.

In the examples and comparative examples, the cation-curable electrode bonding film was an organic resin layer containing conductive particles; the radical curing electrode bonding film is an insulating organic resin layer.

< evaluation of particle replenishment efficiency >

In each bonded body, the number of particles on the bump before bonding (the number of particles before bonding) was calculated according to the following formula.

Number of particles before bonding is equal to particle density (number of particles/mm) of conductive particles²) Area of x bump (mm)²)

The number of conductive particles on the bump after bonding (the number of particles after bonding) was measured by counting with a metallographic microscope

Then, the replenishment efficiency of the conductive particles (particle replenishment efficiency) was calculated from the following equation.

Particle replenishment efficiency (number of particles after conjugation/number of particles before conjugation) × 100%

< measurement of shear Strength of chip >

The resulting joined bodies were measured for their chip shear strength by a chip shear tester (trade name: Daga2400, manufactured by Dage).

< Heat cycle test >

The joined bodies were subjected to thermal cycling under conditions of-40 ℃ for 30 minutes and 100 ℃ for 30 minutes, and the joined bodies were taken out every 100 cycles to measure the connection resistance. The number of cycles in which the connection resistance exceeded 50 Ω was regarded as the number of cycles in which failure occurred.

< adhesive Strength >

ITO glass having an ITO film attached to glass of 0.7mm thickness and FPC (Flexible printed Circuit Board) having a pitch of 50 μm were bonded to each other by heating and pressure bonding at 180 ℃ under 4MPa for 5 seconds with the same cation-curable electrode bonding film and radical-curable electrode bonding film as in examples 1 to 6 and comparative examples 1 to 3.

The adhesive strength of the joined body was measured by a universal tensile tester (Tensilon) (manufactured by Orientec (オリエンテツク)) in accordance with the method shown in FIG. 3. In FIG. 3, the measurement method is 90 ° Peel; the measuring speed is 50 mm/min; the direction of the arrow in fig. 3 is the Y direction; 30 represents glass; 31 denotes FPC or TAB; and 32 denotes an ACF.

The evaluation results of each joined body are shown in table 4 below.

TABLE 4

As is clear from table 4, the bonded bodies of examples 1 to 6 having the structure of the present invention have high conductive particle replenishment efficiency, high bonding strength, and excellent conduction reliability.

On the contrary, the bonded bodies of comparative examples 1 and 2, in which the radical curing type electrode bonding film (layer 2) did not contain an epoxy compound, had low shear strength of the chip and a small number of defective cycles, and thus a sufficient bonding strength could not be obtained. Therefore, the on reliability may be deteriorated.

Further, it can be seen that the joint bodies of comparative examples 1 and 3, in which the minimum melt viscosity of the conductive particle-containing organic resin layer was 10 times smaller than that of the insulating organic resin layer, had low particle replenishment efficiency and were difficult to cope with fine pitch connection.

In comparative example 1, there was no viscosity difference between the lowest melt viscosity (500Pa · s) of the cation curable electrode bonding film C2(ACF) and the lowest melt viscosity (500Pa · s) of the radical curable electrode bonding film R7(NCF), and therefore the particle replenishment efficiency was low and it was impossible to cope with fine pitch connection. However, since there is no viscosity difference between the lowest melt viscosity (500Pa · s) of the cation curing type electrode bonding film C2(ACF) and the lowest melt viscosity (500Pa · s) of the radical curing type electrode bonding film R7(NCF), a mixed layer is easily formed, and the bonding strength is improved.

It is also understood that the joined body of comparative example 2, in which an acrylic resin was added to the cation-curable electrode-bonding film (layer 1), had low adhesive strength, and in order to solve the problems of the present invention, the radical-curable electrode-bonding film (layer 2) had to contain an epoxy resin.

As is clear from comparison of example 4 with example 1, in example 4 in which the hydroxyl group-containing acrylate was added, the adhesive strength was further improved.

It is also found that, although it is considered that the examples 5 and 6 in which the molecular weight of the epoxy compound is small and the epoxy equivalent is large are improved over the prior art, the shear strength of the chip is low and the number of cycles in which defects occur is small as compared with examples 1 to 4.

Reference example 1

< evaluation of bonded body >

A joined body was produced in the same manner as in comparative example 1, except that in comparative example 1, the radical curing electrode bonding film R8 produced in production example 12 was used in place of the radical curing electrode bonding film R7.

The on-resistance of the joined body was measured, and the adhesive strength was measured by the same method as in the above examples and comparative examples.

< evaluation of Corrosion Property >

A radical curing type electrode bonding film R8 was attached to a comb-shaped evaluation element having ITO wiring with a wiring pitch of 15 μm on glass of 1mm thickness, and used as a sample for evaluating corrosivity.

Under an environment of 40 ℃ and 90% RH, 40V DC voltage was applied to the wiring of the sample for evaluating the corrosiveness, and evaluation was performed in the following 3 stages according to the time of occurrence of corrosion.

O: corrosion did not occur even after more than 48 hours.

And (delta): the corrosion appears in 24-48 hours.

X: corrosion occurred before 24 hours had elapsed.

Reference example 2

Evaluation of on-resistance, adhesive strength and corrosion were carried out in the same manner as in reference example 1 except that the cation-curable electrode bonding film C4 prepared in production example 4 was used in place of the cation-curable electrode bonding film C2 in reference example 1 and the radical-curable electrode bonding film R9 prepared in production example 13 was used in place of the radical-curable electrode bonding film R8.

Reference example 3

Evaluation of on-resistance, adhesive strength, and corrosivity was performed in the same manner as in reference example 1, except that the radical-curing electrode bonding film R8 was replaced with the radical-curing electrode bonding film R7 prepared in production example 11 in reference example 1.

Reference example 4

Evaluation of on-resistance, adhesive strength and corrosivity was carried out in the same manner as in reference example 3, except that in reference example 3, the radical-curing electrode bonding film R7 was replaced with the radical-curing electrode bonding film R10 prepared in production example 14.

Reference example 5

Evaluation of on-resistance, adhesive strength, and corrosivity was performed in the same manner as in reference example 2, except that the radical-curing electrode bonding film R9 was replaced with the radical-curing electrode bonding film R11 prepared in production example 15 in reference example 2.

The evaluation results of reference examples 1 to 5 are shown in Table 5 below.

TABLE 5

In reference examples 1 and 2, since the hydroxyl group-containing acrylate-containing radical-curable electrode bonding film was used, it exhibited excellent bonding strength and low on-resistance. In particular, reference example 1, which has a low acid value, is low in corrosivity and is preferably used as a connection film.

In contrast, in reference example 3, since no hydroxyl group-containing acrylate was used in the radical curing type electrode plate, a good adhesive strength could not be obtained.

In reference examples 4 and 5, the adhesive strength was improved by using phosphate acrylate or urethane acrylate, but the reaction of the cationically curable electrode plate was inhibited, and the on-resistance was increased because the uncured state was caused.

Possibility of industrial application

The connection film, the bonded body, and the method for producing the bonded body according to the present invention can be suitably used as a connection film having excellent conductive particle replenishing efficiency and excellent conduction reliability, as well as a bonded body and a method for producing the bonded body.

Claims (6)

1. A connection film for electrically connecting a 1 st circuit element and a2 nd circuit element, wherein the 2 nd circuit element has a film containing nitrogen atoms formed on a surface facing the 1 st circuit element,

the connection film has a 1 st layer on the 1 st circuit element side and a2 nd layer on the 2 nd circuit element side;

the layer 1 contains a cationic curing agent and an epoxy resin; the 2 nd layer contains a radical curing agent, an acrylic resin and an epoxy compound;

any one of the 1 st and 2 nd layers is an organic resin layer containing conductive particles;

the other of the 1 st and 2 nd layers is an insulating organic resin layer having no conductivity;

the minimum melt viscosity of the conductive particle-containing organic resin layer is 10 times or more the minimum melt viscosity of the insulating organic resin layer.

2. The connection film according to claim 1, wherein the epoxy compound has a molecular weight of 900 or more and 50000 or less; the epoxy equivalent is 450 to 5000 inclusive.

3. The tie film of claim 1, wherein the 2 nd layer comprises a hydroxyl-containing acrylate.

4. A bonded body is characterized by comprising a 1 st circuit element, a2 nd circuit element and a connecting film; a film containing nitrogen atoms is formed on a surface of the 2 nd circuit element facing the 1 st circuit element; a connection film electrically connecting the 1 st circuit element and the 2 nd circuit element, the connection film including a 1 st layer on the 1 st circuit element side and a2 nd layer on the 2 nd circuit element side; the first layer 1 contains a cationic curing agent and an epoxy resin, the second layer 2 contains a radical curing agent, an acrylic resin and an epoxy compound, either the first layer 1 or the second layer 2 is an organic resin layer containing conductive particles, the other layer 1 or the second layer 2 is an insulating organic resin layer without conductivity, and the lowest melt viscosity of the organic resin layer containing conductive particles is more than 10 times of the lowest melt viscosity of the insulating organic resin layer.

5. A method for manufacturing a bonded body, comprising a connecting step of connecting a 1 st and a2 nd circuit elements by heating and pressure-bonding via a connecting film; a connection film electrically connecting the 1 st circuit element and the 2 nd circuit element, wherein the 2 nd circuit element has a film containing nitrogen atoms formed on a surface facing the 1 st circuit element, and the connection film includes a 1 st layer located on the 1 st circuit element side and a2 nd layer located on the 2 nd circuit element side; the first layer 1 contains a cationic curing agent and an epoxy resin, the second layer 2 contains a radical curing agent, an acrylic resin and an epoxy compound, either the first layer 1 or the second layer 2 is an organic resin layer containing conductive particles, the other layer 1 or the second layer 2 is an insulating organic resin layer without conductivity, and the lowest melt viscosity of the organic resin layer containing conductive particles is more than 10 times of the lowest melt viscosity of the insulating organic resin layer.

6. The method for manufacturing the joined body according to claim 5, wherein the 1 st circuit element is an LCD panel; the 2 nd circuit element is any one of IC and TAB, have polyimide film;

in the connection step, the 1 st layer is pre-attached to the LCD panel, the polyimide film is pre-set to the 2 nd layer, and the 2 nd circuit element side is pressure-bonded by hot pressing.